/* vi: set sw=4 ts=4: */ /* * A prototype Bourne shell grammar parser. * Intended to follow the original Thompson and Ritchie * "small and simple is beautiful" philosophy, which * incidentally is a good match to today's BusyBox. * * Copyright (C) 2000,2001 Larry Doolittle * Copyright (C) 2008,2009 Denys Vlasenko * * Credits: * The parser routines proper are all original material, first * written Dec 2000 and Jan 2001 by Larry Doolittle. The * execution engine, the builtins, and much of the underlying * support has been adapted from busybox-0.49pre's lash, which is * Copyright (C) 1999-2004 by Erik Andersen * written by Erik Andersen . That, in turn, * is based in part on ladsh.c, by Michael K. Johnson and Erik W. * Troan, which they placed in the public domain. I don't know * how much of the Johnson/Troan code has survived the repeated * rewrites. * * Other credits: * o_addchr() derived from similar w_addchar function in glibc-2.2. * setup_redirect(), redirect_opt_num(), and big chunks of main() * and many builtins derived from contributions by Erik Andersen. * Miscellaneous bugfixes from Matt Kraai. * * There are two big (and related) architecture differences between * this parser and the lash parser. One is that this version is * actually designed from the ground up to understand nearly all * of the Bourne grammar. The second, consequential change is that * the parser and input reader have been turned inside out. Now, * the parser is in control, and asks for input as needed. The old * way had the input reader in control, and it asked for parsing to * take place as needed. The new way makes it much easier to properly * handle the recursion implicit in the various substitutions, especially * across continuation lines. * * POSIX syntax not implemented: * aliases * <(list) and >(list) Process Substitution * Here Documents ( << word ) * Functions * Tilde Expansion * Parameter Expansion for substring processing ${var#word} ${var%word} * * Bash stuff (maybe optionally enable?): * &> and >& redirection of stdout+stderr * Brace expansion * reserved words: [[ ]] function select * substrings ${var:1:5} * * TODOs: * grep for "TODO" and fix (some of them are easy) * change { and } from special chars to reserved words * builtins: return, ulimit * follow IFS rules more precisely, including update semantics * figure out what to do with backslash-newline * continuation lines, both explicit and implicit - done? * SIGHUP handling * ^Z handling (and explain it in comments for mere humans) * separate job control from interactiveness * (testcase: booting with init=/bin/hush does not show prompt (2009-04)) * functions * * Licensed under the GPL v2 or later, see the file LICENSE in this tarball. */ #include "busybox.h" /* for APPLET_IS_NOFORK/NOEXEC */ //TODO: pull in some .h and find out whether we have SINGLE_APPLET_MAIN? //#include "applet_tables.h" doesn't work #include /* #include */ #if ENABLE_HUSH_CASE #include #endif #include "math.h" #ifdef WANT_TO_TEST_NOMMU # undef BB_MMU # undef USE_FOR_NOMMU # undef USE_FOR_MMU # define BB_MMU 0 # define USE_FOR_NOMMU(...) __VA_ARGS__ # define USE_FOR_MMU(...) #endif #if defined SINGLE_APPLET_MAIN /* STANDALONE does not make sense, and won't compile */ #undef CONFIG_FEATURE_SH_STANDALONE #undef ENABLE_FEATURE_SH_STANDALONE #undef USE_FEATURE_SH_STANDALONE #define SKIP_FEATURE_SH_STANDALONE(...) __VA_ARGS__ #define ENABLE_FEATURE_SH_STANDALONE 0 #define USE_FEATURE_SH_STANDALONE(...) #define SKIP_FEATURE_SH_STANDALONE(...) __VA_ARGS__ #endif #if !ENABLE_HUSH_INTERACTIVE #undef ENABLE_FEATURE_EDITING #define ENABLE_FEATURE_EDITING 0 #undef ENABLE_FEATURE_EDITING_FANCY_PROMPT #define ENABLE_FEATURE_EDITING_FANCY_PROMPT 0 #endif /* Do we support ANY keywords? */ #if ENABLE_HUSH_IF || ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE #define HAS_KEYWORDS 1 #define IF_HAS_KEYWORDS(...) __VA_ARGS__ #define IF_HAS_NO_KEYWORDS(...) #else #define HAS_KEYWORDS 0 #define IF_HAS_KEYWORDS(...) #define IF_HAS_NO_KEYWORDS(...) __VA_ARGS__ #endif /* Keep unconditionally on for now */ #define HUSH_DEBUG 1 /* In progress... */ #define ENABLE_HUSH_FUNCTIONS 0 /* If you comment out one of these below, it will be #defined later * to perform debug printfs to stderr: */ #define debug_printf(...) do {} while (0) /* Finer-grained debug switches */ #define debug_printf_parse(...) do {} while (0) #define debug_print_tree(a, b) do {} while (0) #define debug_printf_exec(...) do {} while (0) #define debug_printf_env(...) do {} while (0) #define debug_printf_jobs(...) do {} while (0) #define debug_printf_expand(...) do {} while (0) #define debug_printf_glob(...) do {} while (0) #define debug_printf_list(...) do {} while (0) #define debug_printf_subst(...) do {} while (0) #define debug_printf_clean(...) do {} while (0) #ifndef debug_printf #define debug_printf(...) fprintf(stderr, __VA_ARGS__) #endif #ifndef debug_printf_parse #define debug_printf_parse(...) fprintf(stderr, __VA_ARGS__) #endif #ifndef debug_printf_exec #define debug_printf_exec(...) fprintf(stderr, __VA_ARGS__) #endif #ifndef debug_printf_env #define debug_printf_env(...) fprintf(stderr, __VA_ARGS__) #endif #ifndef debug_printf_jobs #define debug_printf_jobs(...) fprintf(stderr, __VA_ARGS__) #define DEBUG_JOBS 1 #else #define DEBUG_JOBS 0 #endif #ifndef debug_printf_expand #define debug_printf_expand(...) fprintf(stderr, __VA_ARGS__) #define DEBUG_EXPAND 1 #else #define DEBUG_EXPAND 0 #endif #ifndef debug_printf_glob #define debug_printf_glob(...) fprintf(stderr, __VA_ARGS__) #define DEBUG_GLOB 1 #else #define DEBUG_GLOB 0 #endif #ifndef debug_printf_list #define debug_printf_list(...) fprintf(stderr, __VA_ARGS__) #endif #ifndef debug_printf_subst #define debug_printf_subst(...) fprintf(stderr, __VA_ARGS__) #endif #ifndef debug_printf_clean /* broken, of course, but OK for testing */ static const char *indenter(int i) { static const char blanks[] ALIGN1 = " "; return &blanks[sizeof(blanks) - i - 1]; } #define debug_printf_clean(...) fprintf(stderr, __VA_ARGS__) #define DEBUG_CLEAN 1 #else #define DEBUG_CLEAN 0 #endif #if DEBUG_EXPAND static void debug_print_strings(const char *prefix, char **vv) { fprintf(stderr, "%s:\n", prefix); while (*vv) fprintf(stderr, " '%s'\n", *vv++); } #else #define debug_print_strings(prefix, vv) ((void)0) #endif /* * Leak hunting. Use hush_leaktool.sh for post-processing. */ #ifdef FOR_HUSH_LEAKTOOL static void *xxmalloc(int lineno, size_t size) { void *ptr = xmalloc((size + 0xff) & ~0xff); fdprintf(2, "line %d: malloc %p\n", lineno, ptr); return ptr; } static void *xxrealloc(int lineno, void *ptr, size_t size) { ptr = xrealloc(ptr, (size + 0xff) & ~0xff); fdprintf(2, "line %d: realloc %p\n", lineno, ptr); return ptr; } static char *xxstrdup(int lineno, const char *str) { char *ptr = xstrdup(str); fdprintf(2, "line %d: strdup %p\n", lineno, ptr); return ptr; } static void xxfree(void *ptr) { fdprintf(2, "free %p\n", ptr); free(ptr); } #define xmalloc(s) xxmalloc(__LINE__, s) #define xrealloc(p, s) xxrealloc(__LINE__, p, s) #define xstrdup(s) xxstrdup(__LINE__, s) #define free(p) xxfree(p) #endif #define ERR_PTR ((void*)(long)1) static const char hush_version_str[] ALIGN1 = "HUSH_VERSION="BB_VER; #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n" #define SPECIAL_VAR_SYMBOL 3 typedef enum redir_type { REDIRECT_INPUT = 1, REDIRECT_OVERWRITE = 2, REDIRECT_APPEND = 3, REDIRECT_HEREIS = 4, REDIRECT_IO = 5 } redir_type; /* The descrip member of this structure is only used to make * debugging output pretty */ static const struct { int mode; signed char default_fd; char descrip[3]; } redir_table[] = { { 0, 0, "()" }, { O_RDONLY, 0, "<" }, { O_CREAT|O_TRUNC|O_WRONLY, 1, ">" }, { O_CREAT|O_APPEND|O_WRONLY, 1, ">>" }, { O_RDONLY, -1, "<<" }, { O_RDWR, 1, "<>" } }; typedef enum pipe_style { PIPE_SEQ = 1, PIPE_AND = 2, PIPE_OR = 3, PIPE_BG = 4, } pipe_style; typedef enum reserved_style { RES_NONE = 0, #if ENABLE_HUSH_IF RES_IF , RES_THEN , RES_ELIF , RES_ELSE , RES_FI , #endif #if ENABLE_HUSH_LOOPS RES_FOR , RES_WHILE , RES_UNTIL , RES_DO , RES_DONE , #endif #if ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE RES_IN , #endif #if ENABLE_HUSH_CASE RES_CASE , /* two pseudo-keywords support contrived "case" syntax: */ RES_MATCH , /* "word)" */ RES_CASEI , /* "this command is inside CASE" */ RES_ESAC , #endif RES_XXXX , RES_SNTX } reserved_style; typedef struct o_string { char *data; int length; /* position where data is appended */ int maxlen; /* Protect newly added chars against globbing * (by prepending \ to *, ?, [, \) */ smallint o_escape; smallint o_glob; smallint nonnull; smallint has_empty_slot; smallint o_assignment; /* 0:maybe, 1:yes, 2:no */ } o_string; enum { MAYBE_ASSIGNMENT = 0, DEFINITELY_ASSIGNMENT = 1, NOT_ASSIGNMENT = 2, WORD_IS_KEYWORD = 3, /* not assigment, but next word may be: "if v=xyz cmd;" */ }; /* Used for initialization: o_string foo = NULL_O_STRING; */ #define NULL_O_STRING { NULL } /* I can almost use ordinary FILE*. Is open_memstream() universally * available? Where is it documented? */ typedef struct in_str { const char *p; /* eof_flag=1: last char in ->p is really an EOF */ char eof_flag; /* meaningless if ->p == NULL */ char peek_buf[2]; #if ENABLE_HUSH_INTERACTIVE smallint promptme; smallint promptmode; /* 0: PS1, 1: PS2 */ #endif FILE *file; int (*get) (struct in_str *); int (*peek) (struct in_str *); } in_str; #define i_getch(input) ((input)->get(input)) #define i_peek(input) ((input)->peek(input)) struct redir_struct { struct redir_struct *next; char *rd_filename; /* filename */ int fd; /* file descriptor being redirected */ int dup; /* -1, or file descriptor being duplicated */ smallint /*enum redir_type*/ rd_type; }; struct command { pid_t pid; /* 0 if exited */ int assignment_cnt; /* how many argv[i] are assignments? */ smallint is_stopped; /* is the command currently running? */ smallint grp_type; /* GRP_xxx */ struct pipe *group; /* if non-NULL, this "command" is { list }, * ( list ), or a compound statement */ #if !BB_MMU char *group_as_string; #endif char **argv; /* command name and arguments */ struct redir_struct *redirects; /* I/O redirections */ }; /* argv vector may contain variable references (^Cvar^C, ^C0^C etc) * and on execution these are substituted with their values. * Substitution can make _several_ words out of one argv[n]! * Example: argv[0]=='.^C*^C.' here: echo .$*. * References of the form ^C`cmd arg^C are `cmd arg` substitutions. */ #define GRP_NORMAL 0 #define GRP_SUBSHELL 1 #if ENABLE_HUSH_FUNCTIONS #define GRP_FUNCTION 2 #endif struct pipe { struct pipe *next; int num_cmds; /* total number of commands in job */ int alive_cmds; /* number of commands running (not exited) */ int stopped_cmds; /* number of commands alive, but stopped */ #if ENABLE_HUSH_JOB int jobid; /* job number */ pid_t pgrp; /* process group ID for the job */ char *cmdtext; /* name of job */ #endif struct command *cmds; /* array of commands in pipe */ smallint followup; /* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */ IF_HAS_KEYWORDS(smallint pi_inverted;) /* "! cmd | cmd" */ IF_HAS_KEYWORDS(smallint res_word;) /* needed for if, for, while, until... */ }; /* This holds pointers to the various results of parsing */ struct parse_context { /* linked list of pipes */ struct pipe *list_head; /* last pipe (being constructed right now) */ struct pipe *pipe; /* last command in pipe (being constructed right now) */ struct command *command; /* last redirect in command->redirects list */ struct redir_struct *pending_redirect; #if !BB_MMU o_string as_string; #endif #if HAS_KEYWORDS smallint ctx_res_w; smallint ctx_inverted; /* "! cmd | cmd" */ #if ENABLE_HUSH_CASE smallint ctx_dsemicolon; /* ";;" seen */ #endif /* bitmask of FLAG_xxx, for figuring out valid reserved words */ int old_flag; /* group we are enclosed in: * example: "if pipe1; pipe2; then pipe3; fi" * when we see "if" or "then", we malloc and copy current context, * and make ->stack point to it. then we parse pipeN. * when closing "then" / fi" / whatever is found, * we move list_head into ->stack->command->group, * copy ->stack into current context, and delete ->stack. * (parsing of { list } and ( list ) doesn't use this method) */ struct parse_context *stack; #endif }; /* On program start, environ points to initial environment. * putenv adds new pointers into it, unsetenv removes them. * Neither of these (de)allocates the strings. * setenv allocates new strings in malloc space and does putenv, * and thus setenv is unusable (leaky) for shell's purposes */ #define setenv(...) setenv_is_leaky_dont_use() struct variable { struct variable *next; char *varstr; /* points to "name=" portion */ int max_len; /* if > 0, name is part of initial env; else name is malloced */ smallint flg_export; /* putenv should be done on this var */ smallint flg_read_only; }; enum { BC_BREAK = 1, BC_CONTINUE = 2, }; /* "Globals" within this file */ /* Sorted roughly by size (smaller offsets == smaller code) */ struct globals { #if ENABLE_HUSH_INTERACTIVE /* 'interactive_fd' is a fd# open to ctty, if we have one * _AND_ if we decided to act interactively */ int interactive_fd; const char *PS1; const char *PS2; #define G_interactive_fd (G.interactive_fd) #else #define G_interactive_fd 0 #endif #if ENABLE_FEATURE_EDITING line_input_t *line_input_state; #endif pid_t root_pid; pid_t last_bg_pid; #if ENABLE_HUSH_JOB int run_list_level; pid_t saved_tty_pgrp; int last_jobid; struct pipe *job_list; struct pipe *toplevel_list; //// smallint ctrl_z_flag; #endif smallint flag_SIGINT; #if ENABLE_HUSH_LOOPS smallint flag_break_continue; #endif smallint fake_mode; /* These four support $?, $#, and $1 */ smalluint last_return_code; /* are global_argv and global_argv[1..n] malloced? (note: not [0]) */ smalluint global_args_malloced; /* how many non-NULL argv's we have. NB: $# + 1 */ int global_argc; char **global_argv; #if !BB_MMU char *argv0_for_re_execing; char **argv_from_re_execing; #endif #if ENABLE_HUSH_LOOPS unsigned depth_break_continue; unsigned depth_of_loop; #endif const char *ifs; const char *cwd; struct variable *top_var; /* = &G.shell_ver (set in main()) */ struct variable shell_ver; /* Signal and trap handling */ // unsigned count_SIGCHLD; // unsigned handled_SIGCHLD; /* which signals have non-DFL handler (even with no traps set)? */ unsigned non_DFL_mask; char **traps; /* char *traps[NSIG] */ sigset_t blocked_set; sigset_t inherited_set; char user_input_buf[ENABLE_FEATURE_EDITING ? BUFSIZ : 2]; #if ENABLE_FEATURE_SH_STANDALONE struct nofork_save_area nofork_save; #endif #if ENABLE_HUSH_JOB sigjmp_buf toplevel_jb; #endif }; #define G (*ptr_to_globals) /* Not #defining name to G.name - this quickly gets unwieldy * (too many defines). Also, I actually prefer to see when a variable * is global, thus "G." prefix is a useful hint */ #define INIT_G() do { \ SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \ } while (0) /* Function prototypes for builtins */ static int builtin_cd(char **argv); static int builtin_echo(char **argv); static int builtin_eval(char **argv); static int builtin_exec(char **argv); static int builtin_exit(char **argv); static int builtin_export(char **argv); #if ENABLE_HUSH_JOB static int builtin_fg_bg(char **argv); static int builtin_jobs(char **argv); #endif #if ENABLE_HUSH_HELP static int builtin_help(char **argv); #endif static int builtin_pwd(char **argv); static int builtin_read(char **argv); static int builtin_test(char **argv); static int builtin_trap(char **argv); static int builtin_true(char **argv); static int builtin_set(char **argv); static int builtin_shift(char **argv); static int builtin_source(char **argv); static int builtin_umask(char **argv); static int builtin_unset(char **argv); static int builtin_wait(char **argv); #if ENABLE_HUSH_LOOPS static int builtin_break(char **argv); static int builtin_continue(char **argv); #endif /* Table of built-in functions. They can be forked or not, depending on * context: within pipes, they fork. As simple commands, they do not. * When used in non-forking context, they can change global variables * in the parent shell process. If forked, of course they cannot. * For example, 'unset foo | whatever' will parse and run, but foo will * still be set at the end. */ struct built_in_command { const char *cmd; int (*function)(char **argv); #if ENABLE_HUSH_HELP const char *descr; #define BLTIN(cmd, func, help) { cmd, func, help } #else #define BLTIN(cmd, func, help) { cmd, func } #endif }; /* For now, echo and test are unconditionally enabled. * Maybe make it configurable? */ static const struct built_in_command bltins[] = { BLTIN("." , builtin_source , "Run commands in a file"), BLTIN(":" , builtin_true , "No-op"), BLTIN("[" , builtin_test , "Test condition"), #if ENABLE_HUSH_JOB BLTIN("bg" , builtin_fg_bg , "Resume a job in the background"), #endif #if ENABLE_HUSH_LOOPS BLTIN("break" , builtin_break , "Exit from a loop"), #endif BLTIN("cd" , builtin_cd , "Change directory"), #if ENABLE_HUSH_LOOPS BLTIN("continue", builtin_continue, "Start new loop iteration"), #endif BLTIN("echo" , builtin_echo , "Write to stdout"), BLTIN("eval" , builtin_eval , "Construct and run shell command"), BLTIN("exec" , builtin_exec , "Execute command, don't return to shell"), BLTIN("exit" , builtin_exit , "Exit"), BLTIN("export" , builtin_export , "Set environment variable"), #if ENABLE_HUSH_JOB BLTIN("fg" , builtin_fg_bg , "Bring job into the foreground"), #endif #if ENABLE_HUSH_HELP BLTIN("help" , builtin_help , "List shell built-in commands"), #endif #if ENABLE_HUSH_JOB BLTIN("jobs" , builtin_jobs , "List active jobs"), #endif BLTIN("pwd" , builtin_pwd , "Print current directory"), BLTIN("read" , builtin_read , "Input environment variable"), // BLTIN("return" , builtin_return , "Return from a function"), BLTIN("set" , builtin_set , "Set/unset shell local variables"), BLTIN("shift" , builtin_shift , "Shift positional parameters"), BLTIN("test" , builtin_test , "Test condition"), BLTIN("trap" , builtin_trap , "Trap signals"), // BLTIN("ulimit" , builtin_return , "Control resource limits"), BLTIN("umask" , builtin_umask , "Set file creation mask"), BLTIN("unset" , builtin_unset , "Unset environment variable"), BLTIN("wait" , builtin_wait , "Wait for process"), }; static void maybe_die(const char *notice, const char *msg) { /* Was using fancy stuff: * (G_interactive_fd ? bb_error_msg : bb_error_msg_and_die)(...params...) * but it SEGVs. ?! Oh well... explicit temp ptr works around that */ void FAST_FUNC (*fp)(const char *s, ...) = bb_error_msg_and_die; #if ENABLE_HUSH_INTERACTIVE if (G_interactive_fd) fp = bb_error_msg; #endif fp(msg ? "%s: %s" : notice, notice, msg); } #if 1 #define syntax(msg) maybe_die("syntax error", msg); #else /* Debug -- trick gcc to expand __LINE__ and convert to string */ #define __syntax(msg, line) maybe_die("syntax error hush.c:" # line, msg) #define _syntax(msg, line) __syntax(msg, line) #define syntax(msg) _syntax(msg, __LINE__) #endif static int glob_needed(const char *s) { while (*s) { if (*s == '\\') s++; if (*s == '*' || *s == '[' || *s == '?') return 1; s++; } return 0; } static int is_assignment(const char *s) { if (!s || !(isalpha(*s) || *s == '_')) return 0; s++; while (isalnum(*s) || *s == '_') s++; return *s == '='; } /* Replace each \x with x in place, return ptr past NUL. */ static char *unbackslash(char *src) { char *dst = src; while (1) { if (*src == '\\') src++; if ((*dst++ = *src++) == '\0') break; } return dst; } static char **add_strings_to_strings(char **strings, char **add, int need_to_dup) { int i; unsigned count1; unsigned count2; char **v; v = strings; count1 = 0; if (v) { while (*v) { count1++; v++; } } count2 = 0; v = add; while (*v) { count2++; v++; } v = xrealloc(strings, (count1 + count2 + 1) * sizeof(char*)); v[count1 + count2] = NULL; i = count2; while (--i >= 0) v[count1 + i] = (need_to_dup ? xstrdup(add[i]) : add[i]); return v; } static char **add_string_to_strings(char **strings, char *add) { char *v[2]; v[0] = add; v[1] = NULL; return add_strings_to_strings(strings, v, /*dup:*/ 0); } static void putenv_all(char **strings) { if (!strings) return; while (*strings) { debug_printf_env("putenv '%s'\n", *strings); putenv(*strings++); } } static char **putenv_all_and_save_old(char **strings) { char **old = NULL; char **s = strings; if (!strings) return old; while (*strings) { char *v, *eq; eq = strchr(*strings, '='); if (eq) { *eq = '\0'; v = getenv(*strings); *eq = '='; if (v) { /* v points to VAL in VAR=VAL, go back to VAR */ v -= (eq - *strings) + 1; old = add_string_to_strings(old, v); } } strings++; } putenv_all(s); return old; } static void free_strings_and_unsetenv(char **strings, int unset) { char **v; if (!strings) return; v = strings; while (*v) { if (unset) { debug_printf_env("unsetenv '%s'\n", *v); bb_unsetenv(*v); } free(*v++); } free(strings); } static void free_strings(char **strings) { free_strings_and_unsetenv(strings, 0); } /* Basic theory of signal handling in shell * ======================================== * This does not describe what hush does, rather, it is current understanding * what it _should_ do. If it doesn't, it's a bug. * http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#trap * * Signals are handled only after each pipe ("cmd | cmd | cmd" thing) * is finished or backgrounded. It is the same in interactive and * non-interactive shells, and is the same regardless of whether * a user trap handler is installed or a shell special one is in effect. * ^C or ^Z from keyboard seem to execute "at once" because it usually * backgrounds (i.e. stops) or kills all members of currently running * pipe. * * Wait builtin in interruptible by signals for which user trap is set * or by SIGINT in interactive shell. * * Trap handlers will execute even within trap handlers. (right?) * * User trap handlers are forgotten when subshell ("(cmd)") is entered. [TODO] * * If job control is off, backgrounded commands ("cmd &") * have SIGINT, SIGQUIT set to SIG_IGN. * * Commands run in command substitution ("`cmd`") * have SIGTTIN, SIGTTOU, SIGTSTP set to SIG_IGN. * * Ordinary commands have signals set to SIG_IGN/DFL set as inherited * by the shell from its parent. * * Siganls which differ from SIG_DFL action * (note: child (i.e., [v]forked) shell is not an interactive shell): * * SIGQUIT: ignore * SIGTERM (interactive): ignore * SIGHUP (interactive): * send SIGCONT to stopped jobs, send SIGHUP to all jobs and exit * SIGTTIN, SIGTTOU, SIGTSTP (if job control is on): ignore * (note that ^Z is handled not by trapping SIGTSTP, but by seeing * that all pipe members are stopped) (right?) * SIGINT (interactive): wait for last pipe, ignore the rest * of the command line, show prompt. NB: ^C does not send SIGINT * to interactive shell while shell is waiting for a pipe, * since shell is bg'ed (is not in foreground process group). * (check/expand this) * Example 1: this waits 5 sec, but does not execute ls: * "echo $$; sleep 5; ls -l" + "kill -INT " * Example 2: this does not wait and does not execute ls: * "echo $$; sleep 5 & wait; ls -l" + "kill -INT " * Example 3: this does not wait 5 sec, but executes ls: * "sleep 5; ls -l" + press ^C * * (What happens to signals which are IGN on shell start?) * (What happens with signal mask on shell start?) * * Implementation in hush * ====================== * We use in-kernel pending signal mask to determine which signals were sent. * We block all signals which we don't want to take action immediately, * i.e. we block all signals which need to have special handling as described * above, and all signals which have traps set. * After each pipe execution, we extract any pending signals via sigtimedwait() * and act on them. * * unsigned non_DFL_mask: a mask of such "special" signals * sigset_t blocked_set: current blocked signal set * * "trap - SIGxxx": * clear bit in blocked_set unless it is also in non_DFL_mask * "trap 'cmd' SIGxxx": * set bit in blocked_set (even if 'cmd' is '') * after [v]fork, if we plan to be a shell: * nothing for {} child shell (say, "true | { true; true; } | true") * unset all traps if () shell. [TODO] * after [v]fork, if we plan to exec: * POSIX says pending signal mask is cleared in child - no need to clear it. * Restore blocked signal set to one inherited by shell just prior to exec. * * Note: as a result, we do not use signal handlers much. The only uses * are to count SIGCHLDs [disabled - bug somewhere, + bloat] * and to restore tty pgrp on signal-induced exit. */ //static void SIGCHLD_handler(int sig UNUSED_PARAM) //{ // G.count_SIGCHLD++; //} static int check_and_run_traps(int sig) { static const struct timespec zero_timespec = { 0, 0 }; smalluint save_rcode; int last_sig = 0; if (sig) goto jump_in; while (1) { sig = sigtimedwait(&G.blocked_set, NULL, &zero_timespec); if (sig <= 0) break; jump_in: last_sig = sig; if (G.traps && G.traps[sig]) { if (G.traps[sig][0]) { /* We have user-defined handler */ char *argv[] = { NULL, xstrdup(G.traps[sig]), NULL }; save_rcode = G.last_return_code; builtin_eval(argv); free(argv[1]); G.last_return_code = save_rcode; } /* else: "" trap, ignoring signal */ continue; } /* not a trap: special action */ switch (sig) { // case SIGCHLD: // G.count_SIGCHLD++; // break; case SIGINT: bb_putchar('\n'); G.flag_SIGINT = 1; break; //TODO // case SIGHUP: ... // break; default: /* ignored: */ /* SIGTERM, SIGQUIT, SIGTTIN, SIGTTOU, SIGTSTP */ break; } } return last_sig; } #if ENABLE_HUSH_JOB /* Restores tty foreground process group, and exits. * May be called as signal handler for fatal signal * (will faithfully resend signal to itself, producing correct exit state) * or called directly with -EXITCODE. * We also call it if xfunc is exiting. */ static void sigexit(int sig) NORETURN; static void sigexit(int sig) { /* Disable all signals: job control, SIGPIPE, etc. */ sigprocmask_allsigs(SIG_BLOCK); /* Careful: we can end up here after [v]fork. Do not restore * tty pgrp then, only top-level shell process does that */ if (G_interactive_fd && getpid() == G.root_pid) tcsetpgrp(G_interactive_fd, G.saved_tty_pgrp); /* Not a signal, just exit */ if (sig <= 0) _exit(- sig); kill_myself_with_sig(sig); /* does not return */ } #endif /* Restores tty foreground process group, and exits. */ static void hush_exit(int exitcode) NORETURN; static void hush_exit(int exitcode) { if (G.traps && G.traps[0] && G.traps[0][0]) { char *argv[] = { NULL, xstrdup(G.traps[0]), NULL }; //TODO: do we need to prevent recursion? builtin_eval(argv); free(argv[1]); } #if ENABLE_HUSH_JOB fflush(NULL); /* flush all streams */ sigexit(- (exitcode & 0xff)); #else exit(exitcode); #endif } static const char *set_cwd(void) { /* xrealloc_getcwd_or_warn(arg) calls free(arg), * we must not try to free(bb_msg_unknown) */ if (G.cwd == bb_msg_unknown) G.cwd = NULL; G.cwd = xrealloc_getcwd_or_warn((char *)G.cwd); if (!G.cwd) G.cwd = bb_msg_unknown; return G.cwd; } /* Get/check local shell variables */ static struct variable *get_local_var(const char *name) { struct variable *cur; int len; if (!name) return NULL; len = strlen(name); for (cur = G.top_var; cur; cur = cur->next) { if (strncmp(cur->varstr, name, len) == 0 && cur->varstr[len] == '=') return cur; } return NULL; } static const char *get_local_var_value(const char *src) { struct variable *var = get_local_var(src); if (var) return strchr(var->varstr, '=') + 1; return NULL; } /* str holds "NAME=VAL" and is expected to be malloced. * We take ownership of it. * flg_export: * 0: do not export * 1: export * -1: if NAME is set, leave export status alone * if NAME is not set, do not export * flg_read_only is set only when we handle -R var=val */ #if BB_MMU #define set_local_var(str, flg_export, flg_read_only) \ set_local_var(str, flg_export) #endif static int set_local_var(char *str, int flg_export, int flg_read_only) { struct variable *cur; char *value; int name_len; value = strchr(str, '='); if (!value) { /* not expected to ever happen? */ free(str); return -1; } name_len = value - str + 1; /* including '=' */ cur = G.top_var; /* cannot be NULL (we have HUSH_VERSION and it's RO) */ while (1) { if (strncmp(cur->varstr, str, name_len) != 0) { if (!cur->next) { /* Bail out. Note that now cur points * to last var in linked list */ break; } cur = cur->next; continue; } /* We found an existing var with this name */ *value = '\0'; if (cur->flg_read_only) { #if !BB_MMU if (!flg_read_only) #endif bb_error_msg("%s: readonly variable", str); free(str); return -1; } debug_printf_env("%s: unsetenv '%s'\n", __func__, str); unsetenv(str); /* just in case */ *value = '='; if (strcmp(cur->varstr, str) == 0) { free_and_exp: free(str); goto exp; } if (cur->max_len >= strlen(str)) { /* This one is from startup env, reuse space */ strcpy(cur->varstr, str); goto free_and_exp; } /* max_len == 0 signifies "malloced" var, which we can * (and has to) free */ if (!cur->max_len) free(cur->varstr); cur->max_len = 0; goto set_str_and_exp; } /* Not found - create next variable struct */ cur->next = xzalloc(sizeof(*cur)); cur = cur->next; set_str_and_exp: cur->varstr = str; #if !BB_MMU cur->flg_read_only = flg_read_only; #endif exp: if (flg_export == 1) cur->flg_export = 1; if (cur->flg_export) { debug_printf_env("%s: putenv '%s'\n", __func__, cur->varstr); return putenv(cur->varstr); } return 0; } static int unset_local_var(const char *name) { struct variable *cur; struct variable *prev = prev; /* for gcc */ int name_len; if (!name) return EXIT_SUCCESS; name_len = strlen(name); cur = G.top_var; while (cur) { if (strncmp(cur->varstr, name, name_len) == 0 && cur->varstr[name_len] == '=') { if (cur->flg_read_only) { bb_error_msg("%s: readonly variable", name); return EXIT_FAILURE; } /* prev is ok to use here because 1st variable, HUSH_VERSION, * is ro, and we cannot reach this code on the 1st pass */ prev->next = cur->next; debug_printf_env("%s: unsetenv '%s'\n", __func__, cur->varstr); bb_unsetenv(cur->varstr); if (!cur->max_len) free(cur->varstr); free(cur); return EXIT_SUCCESS; } prev = cur; cur = cur->next; } return EXIT_SUCCESS; } #if ENABLE_SH_MATH_SUPPORT #define is_name(c) ((c) == '_' || isalpha((unsigned char)(c))) #define is_in_name(c) ((c) == '_' || isalnum((unsigned char)(c))) static char *endofname(const char *name) { char *p; p = (char *) name; if (!is_name(*p)) return p; while (*++p) { if (!is_in_name(*p)) break; } return p; } static void arith_set_local_var(const char *name, const char *val, int flags) { /* arith code doesnt malloc space, so do it for it */ char *var = xasprintf("%s=%s", name, val); set_local_var(var, flags, 0); } #endif /* * in_str support */ static int static_get(struct in_str *i) { int ch = *i->p++; if (ch != '\0') return ch; i->p--; return EOF; } static int static_peek(struct in_str *i) { return *i->p; } #if ENABLE_HUSH_INTERACTIVE static void cmdedit_set_initial_prompt(void) { if (ENABLE_FEATURE_EDITING_FANCY_PROMPT) { G.PS1 = getenv("PS1"); if (G.PS1 == NULL) G.PS1 = "\\w \\$ "; } else G.PS1 = NULL; } static const char* setup_prompt_string(int promptmode) { const char *prompt_str; debug_printf("setup_prompt_string %d ", promptmode); if (!ENABLE_FEATURE_EDITING_FANCY_PROMPT) { /* Set up the prompt */ if (promptmode == 0) { /* PS1 */ free((char*)G.PS1); G.PS1 = xasprintf("%s %c ", G.cwd, (geteuid() != 0) ? '$' : '#'); prompt_str = G.PS1; } else prompt_str = G.PS2; } else prompt_str = (promptmode == 0) ? G.PS1 : G.PS2; debug_printf("result '%s'\n", prompt_str); return prompt_str; } static void get_user_input(struct in_str *i) { int r; const char *prompt_str; prompt_str = setup_prompt_string(i->promptmode); #if ENABLE_FEATURE_EDITING /* Enable command line editing only while a command line * is actually being read */ do { G.flag_SIGINT = 0; /* buglet: SIGINT will not make new prompt to appear _at once_, * only after . (^C will work) */ r = read_line_input(prompt_str, G.user_input_buf, BUFSIZ-1, G.line_input_state); /* catch *SIGINT* etc (^C is handled by read_line_input) */ check_and_run_traps(0); } while (r == 0 || G.flag_SIGINT); /* repeat if ^C or SIGINT */ i->eof_flag = (r < 0); if (i->eof_flag) { /* EOF/error detected */ G.user_input_buf[0] = EOF; /* yes, it will be truncated, it's ok */ G.user_input_buf[1] = '\0'; } #else do { G.flag_SIGINT = 0; fputs(prompt_str, stdout); fflush(stdout); G.user_input_buf[0] = r = fgetc(i->file); /*G.user_input_buf[1] = '\0'; - already is and never changed */ //do we need check_and_run_traps(0)? (maybe only if stdin) } while (G.flag_SIGINT); i->eof_flag = (r == EOF); #endif i->p = G.user_input_buf; } #endif /* INTERACTIVE */ /* This is the magic location that prints prompts * and gets data back from the user */ static int file_get(struct in_str *i) { int ch; /* If there is data waiting, eat it up */ if (i->p && *i->p) { #if ENABLE_HUSH_INTERACTIVE take_cached: #endif ch = *i->p++; if (i->eof_flag && !*i->p) ch = EOF; /* note: ch is never NUL */ } else { /* need to double check i->file because we might be doing something * more complicated by now, like sourcing or substituting. */ #if ENABLE_HUSH_INTERACTIVE if (G_interactive_fd && i->promptme && i->file == stdin) { do { get_user_input(i); } while (!*i->p); /* need non-empty line */ i->promptmode = 1; /* PS2 */ i->promptme = 0; goto take_cached; } #endif do ch = fgetc(i->file); while (ch == '\0'); } debug_printf("file_get: got '%c' %d\n", ch, ch); #if ENABLE_HUSH_INTERACTIVE if (ch == '\n') i->promptme = 1; #endif return ch; } /* All callers guarantee this routine will never * be used right after a newline, so prompting is not needed. */ static int file_peek(struct in_str *i) { int ch; if (i->p && *i->p) { if (i->eof_flag && !i->p[1]) return EOF; return *i->p; /* note: ch is never NUL */ } do ch = fgetc(i->file); while (ch == '\0'); i->eof_flag = (ch == EOF); i->peek_buf[0] = ch; i->peek_buf[1] = '\0'; i->p = i->peek_buf; debug_printf("file_peek: got '%c' %d\n", ch, ch); return ch; } static void setup_file_in_str(struct in_str *i, FILE *f) { i->peek = file_peek; i->get = file_get; #if ENABLE_HUSH_INTERACTIVE i->promptme = 1; i->promptmode = 0; /* PS1 */ #endif i->file = f; i->p = NULL; } static void setup_string_in_str(struct in_str *i, const char *s) { i->peek = static_peek; i->get = static_get; #if ENABLE_HUSH_INTERACTIVE i->promptme = 1; i->promptmode = 0; /* PS1 */ #endif i->p = s; i->eof_flag = 0; } /* * o_string support */ #define B_CHUNK (32 * sizeof(char*)) static void o_reset(o_string *o) { o->length = 0; o->nonnull = 0; if (o->data) o->data[0] = '\0'; } static void o_free(o_string *o) { free(o->data); memset(o, 0, sizeof(*o)); } static ALWAYS_INLINE void o_free_unsafe(o_string *o) { free(o->data); } static void o_grow_by(o_string *o, int len) { if (o->length + len > o->maxlen) { o->maxlen += (2*len > B_CHUNK ? 2*len : B_CHUNK); o->data = xrealloc(o->data, 1 + o->maxlen); } } static void o_addchr(o_string *o, int ch) { debug_printf("o_addchr: '%c' o->length=%d o=%p\n", ch, o->length, o); o_grow_by(o, 1); o->data[o->length] = ch; o->length++; o->data[o->length] = '\0'; } static void o_addblock(o_string *o, const char *str, int len) { o_grow_by(o, len); memcpy(&o->data[o->length], str, len); o->length += len; o->data[o->length] = '\0'; } #if !BB_MMU static void o_addstr(o_string *o, const char *str) { o_addblock(o, str, strlen(str)); } #endif static void o_addstr_with_NUL(o_string *o, const char *str) { o_addblock(o, str, strlen(str) + 1); } static void o_addblock_duplicate_backslash(o_string *o, const char *str, int len) { while (len) { o_addchr(o, *str); if (*str++ == '\\' && (*str != '*' && *str != '?' && *str != '[') ) { o_addchr(o, '\\'); } len--; } } /* My analysis of quoting semantics tells me that state information * is associated with a destination, not a source. */ static void o_addqchr(o_string *o, int ch) { int sz = 1; char *found = strchr("*?[\\", ch); if (found) sz++; o_grow_by(o, sz); if (found) { o->data[o->length] = '\\'; o->length++; } o->data[o->length] = ch; o->length++; o->data[o->length] = '\0'; } static void o_addQchr(o_string *o, int ch) { int sz = 1; if (o->o_escape && strchr("*?[\\", ch)) { sz++; o->data[o->length] = '\\'; o->length++; } o_grow_by(o, sz); o->data[o->length] = ch; o->length++; o->data[o->length] = '\0'; } static void o_addQstr(o_string *o, const char *str, int len) { if (!o->o_escape) { o_addblock(o, str, len); return; } while (len) { char ch; int sz; int ordinary_cnt = strcspn(str, "*?[\\"); if (ordinary_cnt > len) /* paranoia */ ordinary_cnt = len; o_addblock(o, str, ordinary_cnt); if (ordinary_cnt == len) return; str += ordinary_cnt; len -= ordinary_cnt + 1; /* we are processing + 1 char below */ ch = *str++; sz = 1; if (ch) { /* it is necessarily one of "*?[\\" */ sz++; o->data[o->length] = '\\'; o->length++; } o_grow_by(o, sz); o->data[o->length] = ch; o->length++; o->data[o->length] = '\0'; } } /* A special kind of o_string for $VAR and `cmd` expansion. * It contains char* list[] at the beginning, which is grown in 16 element * increments. Actual string data starts at the next multiple of 16 * (char*). * list[i] contains an INDEX (int!) into this string data. * It means that if list[] needs to grow, data needs to be moved higher up * but list[i]'s need not be modified. * NB: remembering how many list[i]'s you have there is crucial. * o_finalize_list() operation post-processes this structure - calculates * and stores actual char* ptrs in list[]. Oh, it NULL terminates it as well. */ #if DEBUG_EXPAND || DEBUG_GLOB static void debug_print_list(const char *prefix, o_string *o, int n) { char **list = (char**)o->data; int string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]); int i = 0; fprintf(stderr, "%s: list:%p n:%d string_start:%d length:%d maxlen:%d\n", prefix, list, n, string_start, o->length, o->maxlen); while (i < n) { fprintf(stderr, " list[%d]=%d '%s' %p\n", i, (int)list[i], o->data + (int)list[i] + string_start, o->data + (int)list[i] + string_start); i++; } if (n) { const char *p = o->data + (int)list[n - 1] + string_start; fprintf(stderr, " total_sz:%ld\n", (long)((p + strlen(p) + 1) - o->data)); } } #else #define debug_print_list(prefix, o, n) ((void)0) #endif /* n = o_save_ptr_helper(str, n) "starts new string" by storing an index value * in list[n] so that it points past last stored byte so far. * It returns n+1. */ static int o_save_ptr_helper(o_string *o, int n) { char **list = (char**)o->data; int string_start; int string_len; if (!o->has_empty_slot) { string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]); string_len = o->length - string_start; if (!(n & 0xf)) { /* 0, 0x10, 0x20...? */ debug_printf_list("list[%d]=%d string_start=%d (growing)\n", n, string_len, string_start); /* list[n] points to string_start, make space for 16 more pointers */ o->maxlen += 0x10 * sizeof(list[0]); o->data = xrealloc(o->data, o->maxlen + 1); list = (char**)o->data; memmove(list + n + 0x10, list + n, string_len); o->length += 0x10 * sizeof(list[0]); } else { debug_printf_list("list[%d]=%d string_start=%d\n", n, string_len, string_start); } } else { /* We have empty slot at list[n], reuse without growth */ string_start = ((n+1 + 0xf) & ~0xf) * sizeof(list[0]); /* NB: n+1! */ string_len = o->length - string_start; debug_printf_list("list[%d]=%d string_start=%d (empty slot)\n", n, string_len, string_start); o->has_empty_slot = 0; } list[n] = (char*)(ptrdiff_t)string_len; return n + 1; } /* "What was our last o_save_ptr'ed position (byte offset relative o->data)?" */ static int o_get_last_ptr(o_string *o, int n) { char **list = (char**)o->data; int string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]); return ((int)(ptrdiff_t)list[n-1]) + string_start; } /* o_glob performs globbing on last list[], saving each result * as a new list[]. */ static int o_glob(o_string *o, int n) { glob_t globdata; int gr; char *pattern; debug_printf_glob("start o_glob: n:%d o->data:%p\n", n, o->data); if (!o->data) return o_save_ptr_helper(o, n); pattern = o->data + o_get_last_ptr(o, n); debug_printf_glob("glob pattern '%s'\n", pattern); if (!glob_needed(pattern)) { literal: o->length = unbackslash(pattern) - o->data; debug_printf_glob("glob pattern '%s' is literal\n", pattern); return o_save_ptr_helper(o, n); } memset(&globdata, 0, sizeof(globdata)); gr = glob(pattern, 0, NULL, &globdata); debug_printf_glob("glob('%s'):%d\n", pattern, gr); if (gr == GLOB_NOSPACE) bb_error_msg_and_die("out of memory during glob"); if (gr == GLOB_NOMATCH) { globfree(&globdata); goto literal; } if (gr != 0) { /* GLOB_ABORTED ? */ //TODO: testcase for bad glob pattern behavior bb_error_msg("glob(3) error %d on '%s'", gr, pattern); } if (globdata.gl_pathv && globdata.gl_pathv[0]) { char **argv = globdata.gl_pathv; o->length = pattern - o->data; /* "forget" pattern */ while (1) { o_addstr_with_NUL(o, *argv); n = o_save_ptr_helper(o, n); argv++; if (!*argv) break; } } globfree(&globdata); if (DEBUG_GLOB) debug_print_list("o_glob returning", o, n); return n; } /* If o->o_glob == 1, glob the string so far remembered. * Otherwise, just finish current list[] and start new */ static int o_save_ptr(o_string *o, int n) { if (o->o_glob) { /* if globbing is requested */ /* If o->has_empty_slot, list[n] was already globbed * (if it was requested back then when it was filled) * so don't do that again! */ if (!o->has_empty_slot) return o_glob(o, n); /* o_save_ptr_helper is inside */ } return o_save_ptr_helper(o, n); } /* "Please convert list[n] to real char* ptrs, and NULL terminate it." */ static char **o_finalize_list(o_string *o, int n) { char **list; int string_start; n = o_save_ptr(o, n); /* force growth for list[n] if necessary */ if (DEBUG_EXPAND) debug_print_list("finalized", o, n); debug_printf_expand("finalized n:%d\n", n); list = (char**)o->data; string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]); list[--n] = NULL; while (n) { n--; list[n] = o->data + (int)(ptrdiff_t)list[n] + string_start; } return list; } /* Expansion can recurse */ #if ENABLE_HUSH_TICK static int process_command_subs(o_string *dest, const char *s); #endif static char *expand_string_to_string(const char *str); #if BB_MMU #define parse_stream_dquoted(as_string, dest, input, dquote_end) \ parse_stream_dquoted(dest, input, dquote_end) #endif static int parse_stream_dquoted(o_string *as_string, o_string *dest, struct in_str *input, int dquote_end); /* expand_strvec_to_strvec() takes a list of strings, expands * all variable references within and returns a pointer to * a list of expanded strings, possibly with larger number * of strings. (Think VAR="a b"; echo $VAR). * This new list is allocated as a single malloc block. * NULL-terminated list of char* pointers is at the beginning of it, * followed by strings themself. * Caller can deallocate entire list by single free(list). */ /* Store given string, finalizing the word and starting new one whenever * we encounter IFS char(s). This is used for expanding variable values. * End-of-string does NOT finalize word: think about 'echo -$VAR-' */ static int expand_on_ifs(o_string *output, int n, const char *str) { while (1) { int word_len = strcspn(str, G.ifs); if (word_len) { if (output->o_escape || !output->o_glob) o_addQstr(output, str, word_len); else /* protect backslashes against globbing up :) */ o_addblock_duplicate_backslash(output, str, word_len); str += word_len; } if (!*str) /* EOL - do not finalize word */ break; o_addchr(output, '\0'); debug_print_list("expand_on_ifs", output, n); n = o_save_ptr(output, n); str += strspn(str, G.ifs); /* skip ifs chars */ } debug_print_list("expand_on_ifs[1]", output, n); return n; } /* Expand all variable references in given string, adding words to list[] * at n, n+1,... positions. Return updated n (so that list[n] is next one * to be filled). This routine is extremely tricky: has to deal with * variables/parameters with whitespace, $* and $@, and constructs like * 'echo -$*-'. If you play here, you must run testsuite afterwards! */ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask) { /* or_mask is either 0 (normal case) or 0x80 * (expansion of right-hand side of assignment == 1-element expand. * It will also do no globbing, and thus we must not backslash-quote!) */ char first_ch, ored_ch; int i; const char *val; char *p; ored_ch = 0; debug_printf_expand("expand_vars_to_list: arg '%s'\n", arg); debug_print_list("expand_vars_to_list", output, n); n = o_save_ptr(output, n); debug_print_list("expand_vars_to_list[0]", output, n); while ((p = strchr(arg, SPECIAL_VAR_SYMBOL)) != NULL) { #if ENABLE_HUSH_TICK o_string subst_result = NULL_O_STRING; #endif #if ENABLE_SH_MATH_SUPPORT char arith_buf[sizeof(arith_t)*3 + 2]; #endif o_addblock(output, arg, p - arg); debug_print_list("expand_vars_to_list[1]", output, n); arg = ++p; p = strchr(p, SPECIAL_VAR_SYMBOL); first_ch = arg[0] | or_mask; /* forced to "quoted" if or_mask = 0x80 */ /* "$@" is special. Even if quoted, it can still * expand to nothing (not even an empty string) */ if ((first_ch & 0x7f) != '@') ored_ch |= first_ch; val = NULL; switch (first_ch & 0x7f) { /* Highest bit in first_ch indicates that var is double-quoted */ case '$': /* pid */ val = utoa(G.root_pid); break; case '!': /* bg pid */ val = G.last_bg_pid ? utoa(G.last_bg_pid) : (char*)""; break; case '?': /* exitcode */ val = utoa(G.last_return_code); break; case '#': /* argc */ if (arg[1] != SPECIAL_VAR_SYMBOL) /* actually, it's a ${#var} */ goto case_default; val = utoa(G.global_argc ? G.global_argc-1 : 0); break; case '*': case '@': i = 1; if (!G.global_argv[i]) break; ored_ch |= first_ch; /* do it for "$@" _now_, when we know it's not empty */ if (!(first_ch & 0x80)) { /* unquoted $* or $@ */ smallint sv = output->o_escape; /* unquoted var's contents should be globbed, so don't escape */ output->o_escape = 0; while (G.global_argv[i]) { n = expand_on_ifs(output, n, G.global_argv[i]); debug_printf_expand("expand_vars_to_list: argv %d (last %d)\n", i, G.global_argc - 1); if (G.global_argv[i++][0] && G.global_argv[i]) { /* this argv[] is not empty and not last: * put terminating NUL, start new word */ o_addchr(output, '\0'); debug_print_list("expand_vars_to_list[2]", output, n); n = o_save_ptr(output, n); debug_print_list("expand_vars_to_list[3]", output, n); } } output->o_escape = sv; } else /* If or_mask is nonzero, we handle assignment 'a=....$@.....' * and in this case should treat it like '$*' - see 'else...' below */ if (first_ch == ('@'|0x80) && !or_mask) { /* quoted $@ */ while (1) { o_addQstr(output, G.global_argv[i], strlen(G.global_argv[i])); if (++i >= G.global_argc) break; o_addchr(output, '\0'); debug_print_list("expand_vars_to_list[4]", output, n); n = o_save_ptr(output, n); } } else { /* quoted $*: add as one word */ while (1) { o_addQstr(output, G.global_argv[i], strlen(G.global_argv[i])); if (!G.global_argv[++i]) break; if (G.ifs[0]) o_addchr(output, G.ifs[0]); } } break; case SPECIAL_VAR_SYMBOL: /* */ /* "Empty variable", used to make "" etc to not disappear */ arg++; ored_ch = 0x80; break; #if ENABLE_HUSH_TICK case '`': /* `cmd */ *p = '\0'; arg++; //TODO: can we just stuff it into "output" directly? debug_printf_subst("SUBST '%s' first_ch %x\n", arg, first_ch); process_command_subs(&subst_result, arg); debug_printf_subst("SUBST RES '%s'\n", subst_result.data); val = subst_result.data; goto store_val; #endif #if ENABLE_SH_MATH_SUPPORT case '+': { /* +cmd */ arith_eval_hooks_t hooks; arith_t res; int errcode; char *exp_str; arg++; /* skip '+' */ *p = '\0'; /* replace trailing */ debug_printf_subst("ARITH '%s' first_ch %x\n", arg, first_ch); /* Optional: skip expansion if expr is simple ("a + 3", "i++" etc) */ exp_str = NULL; if (strchr(arg, '$') != NULL #if ENABLE_HUSH_TICK || strchr(arg, '`') != NULL #endif ) { /* We need to expand. Example: * echo $(($a + `echo 1`)) $((1 + $((2)) )) */ struct in_str input; o_string dest = NULL_O_STRING; setup_string_in_str(&input, arg); parse_stream_dquoted(NULL, &dest, &input, EOF); //bb_error_msg("'%s' -> '%s'", arg, dest.data); exp_str = expand_string_to_string(dest.data); //bb_error_msg("'%s' -> '%s'", dest.data, exp_str); o_free(&dest); } hooks.lookupvar = get_local_var_value; hooks.setvar = arith_set_local_var; hooks.endofname = endofname; res = arith(exp_str ? exp_str : arg, &errcode, &hooks); free(exp_str); if (errcode < 0) { switch (errcode) { case -3: maybe_die("arith", "exponent less than 0"); break; case -2: maybe_die("arith", "divide by zero"); break; case -5: maybe_die("arith", "expression recursion loop detected"); break; default: maybe_die("arith", "syntax error"); break; } } debug_printf_subst("ARITH RES '"arith_t_fmt"'\n", res); sprintf(arith_buf, arith_t_fmt, res); val = arith_buf; break; } #endif default: /* varname */ case_default: { bool exp_len = false; bool exp_null = false; char *var = arg; char exp_save = exp_save; /* for compiler */ char exp_op = exp_op; /* for compiler */ char *exp_word = exp_word; /* for compiler */ size_t exp_off = 0; *p = '\0'; arg[0] = first_ch & 0x7f; /* prepare for expansions */ if (var[0] == '#') { /* handle length expansion ${#var} */ exp_len = true; ++var; } else { /* maybe handle parameter expansion */ exp_off = strcspn(var, ":-=+?"); if (!var[exp_off]) exp_off = 0; if (exp_off) { exp_save = var[exp_off]; exp_null = exp_save == ':'; exp_word = var + exp_off; if (exp_null) ++exp_word; exp_op = *exp_word++; var[exp_off] = '\0'; } } /* lookup the variable in question */ if (isdigit(var[0])) { /* handle_dollar() should have vetted var for us */ i = xatoi_u(var); if (i < G.global_argc) val = G.global_argv[i]; /* else val remains NULL: $N with too big N */ } else val = get_local_var_value(var); /* handle any expansions */ if (exp_len) { debug_printf_expand("expand: length of '%s' = ", val); val = utoa(val ? strlen(val) : 0); debug_printf_expand("%s\n", val); } else if (exp_off) { /* we need to do an expansion */ int exp_test = (!val || (exp_null && !val[0])); if (exp_op == '+') exp_test = !exp_test; debug_printf_expand("expand: op:%c (null:%s) test:%i\n", exp_op, exp_null ? "true" : "false", exp_test); if (exp_test) { if (exp_op == '?') maybe_die(var, *exp_word ? exp_word : "parameter null or not set"); else val = exp_word; if (exp_op == '=') { if (isdigit(var[0]) || var[0] == '#') { maybe_die(var, "special vars cannot assign in this way"); val = NULL; } else { char *new_var = xmalloc(strlen(var) + strlen(val) + 2); sprintf(new_var, "%s=%s", var, val); set_local_var(new_var, -1, 0); } } } var[exp_off] = exp_save; } arg[0] = first_ch; #if ENABLE_HUSH_TICK store_val: #endif if (!(first_ch & 0x80)) { /* unquoted $VAR */ debug_printf_expand("unquoted '%s', output->o_escape:%d\n", val, output->o_escape); if (val) { /* unquoted var's contents should be globbed, so don't escape */ smallint sv = output->o_escape; output->o_escape = 0; n = expand_on_ifs(output, n, val); val = NULL; output->o_escape = sv; } } else { /* quoted $VAR, val will be appended below */ debug_printf_expand("quoted '%s', output->o_escape:%d\n", val, output->o_escape); } } /* default: */ } /* switch (char after ) */ if (val) { o_addQstr(output, val, strlen(val)); } /* Do the check to avoid writing to a const string */ if (*p != SPECIAL_VAR_SYMBOL) *p = SPECIAL_VAR_SYMBOL; #if ENABLE_HUSH_TICK o_free(&subst_result); #endif arg = ++p; } /* end of "while (SPECIAL_VAR_SYMBOL is found) ..." */ if (arg[0]) { debug_print_list("expand_vars_to_list[a]", output, n); /* this part is literal, and it was already pre-quoted * if needed (much earlier), do not use o_addQstr here! */ o_addstr_with_NUL(output, arg); debug_print_list("expand_vars_to_list[b]", output, n); } else if (output->length == o_get_last_ptr(output, n) /* expansion is empty */ && !(ored_ch & 0x80) /* and all vars were not quoted. */ ) { n--; /* allow to reuse list[n] later without re-growth */ output->has_empty_slot = 1; } else { o_addchr(output, '\0'); } return n; } static char **expand_variables(char **argv, int or_mask) { int n; char **list; char **v; o_string output = NULL_O_STRING; if (or_mask & 0x100) { output.o_escape = 1; /* protect against globbing for "$var" */ /* (unquoted $var will temporarily switch it off) */ output.o_glob = 1; } n = 0; v = argv; while (*v) { n = expand_vars_to_list(&output, n, *v, (char)or_mask); v++; } debug_print_list("expand_variables", &output, n); /* output.data (malloced in one block) gets returned in "list" */ list = o_finalize_list(&output, n); debug_print_strings("expand_variables[1]", list); return list; } static char **expand_strvec_to_strvec(char **argv) { return expand_variables(argv, 0x100); } /* Used for expansion of right hand of assignments */ /* NB: should NOT do globbing! "export v=/bin/c*; env | grep ^v=" outputs * "v=/bin/c*" */ static char *expand_string_to_string(const char *str) { char *argv[2], **list; argv[0] = (char*)str; argv[1] = NULL; list = expand_variables(argv, 0x80); /* 0x80: make one-element expansion */ if (HUSH_DEBUG) if (!list[0] || list[1]) bb_error_msg_and_die("BUG in varexp2"); /* actually, just move string 2*sizeof(char*) bytes back */ overlapping_strcpy((char*)list, list[0]); debug_printf_expand("string_to_string='%s'\n", (char*)list); return (char*)list; } /* Used for "eval" builtin */ static char* expand_strvec_to_string(char **argv) { char **list; list = expand_variables(argv, 0x80); /* Convert all NULs to spaces */ if (list[0]) { int n = 1; while (list[n]) { if (HUSH_DEBUG) if (list[n-1] + strlen(list[n-1]) + 1 != list[n]) bb_error_msg_and_die("BUG in varexp3"); list[n][-1] = ' '; /* TODO: or to G.ifs[0]? */ n++; } } overlapping_strcpy((char*)list, list[0]); debug_printf_expand("strvec_to_string='%s'\n", (char*)list); return (char*)list; } static char **expand_assignments(char **argv, int count) { int i; char **p = NULL; /* Expand assignments into one string each */ for (i = 0; i < count; i++) { p = add_string_to_strings(p, expand_string_to_string(argv[i])); } return p; } /* squirrel != NULL means we squirrel away copies of stdin, stdout, * and stderr if they are redirected. */ static int setup_redirects(struct command *prog, int squirrel[]) { int openfd, mode; struct redir_struct *redir; for (redir = prog->redirects; redir; redir = redir->next) { if (redir->dup == -1 && redir->rd_filename == NULL) { /* something went wrong in the parse. Pretend it didn't happen */ continue; } if (redir->dup == -1) { char *p; mode = redir_table[redir->rd_type].mode; //TODO: check redir for names like '\\' p = expand_string_to_string(redir->rd_filename); openfd = open_or_warn(p, mode); free(p); if (openfd < 0) { /* this could get lost if stderr has been redirected, but bash and ash both lose it as well (though zsh doesn't!) */ return 1; } } else { openfd = redir->dup; } if (openfd != redir->fd) { if (squirrel && redir->fd < 3) { squirrel[redir->fd] = dup(redir->fd); } if (openfd == -3) { //close(openfd); // close(-3) ??! } else { dup2(openfd, redir->fd); if (redir->dup == -1) close(openfd); } } } return 0; } static void restore_redirects(int squirrel[]) { int i, fd; for (i = 0; i < 3; i++) { fd = squirrel[i]; if (fd != -1) { /* We simply die on error */ xmove_fd(fd, i); } } } #if !DEBUG_CLEAN #define free_pipe_list(head, indent) free_pipe_list(head) #define free_pipe(pi, indent) free_pipe(pi) #endif static void free_pipe_list(struct pipe *head, int indent); /* Return code is the exit status of the pipe */ static void free_pipe(struct pipe *pi, int indent) { char **p; struct command *command; struct redir_struct *r, *rnext; int a, i; if (pi->stopped_cmds > 0) /* why? */ return; debug_printf_clean("%s run pipe: (pid %d)\n", indenter(indent), getpid()); for (i = 0; i < pi->num_cmds; i++) { command = &pi->cmds[i]; debug_printf_clean("%s command %d:\n", indenter(indent), i); if (command->argv) { for (a = 0, p = command->argv; *p; a++, p++) { debug_printf_clean("%s argv[%d] = %s\n", indenter(indent), a, *p); } free_strings(command->argv); command->argv = NULL; } /* not "else if": on syntax error, we may have both! */ if (command->group) { debug_printf_clean("%s begin group (grp_type:%d)\n", indenter(indent), command->grp_type); free_pipe_list(command->group, indent+3); debug_printf_clean("%s end group\n", indenter(indent)); command->group = NULL; } #if !BB_MMU free(command->group_as_string); command->group_as_string = NULL; #endif for (r = command->redirects; r; r = rnext) { debug_printf_clean("%s redirect %d%s", indenter(indent), r->fd, redir_table[r->rd_type].descrip); if (r->dup == -1) { /* guard against the case >$FOO, where foo is unset or blank */ if (r->rd_filename) { debug_printf_clean(" %s\n", r->rd_filename); free(r->rd_filename); r->rd_filename = NULL; } } else { debug_printf_clean("&%d\n", r->dup); } rnext = r->next; free(r); } command->redirects = NULL; } free(pi->cmds); /* children are an array, they get freed all at once */ pi->cmds = NULL; #if ENABLE_HUSH_JOB free(pi->cmdtext); pi->cmdtext = NULL; #endif } static void free_pipe_list(struct pipe *head, int indent) { struct pipe *pi, *next; for (pi = head; pi; pi = next) { #if HAS_KEYWORDS debug_printf_clean("%s pipe reserved mode %d\n", indenter(indent), pi->res_word); #endif free_pipe(pi, indent); debug_printf_clean("%s pipe followup code %d\n", indenter(indent), pi->followup); next = pi->next; /*pi->next = NULL;*/ free(pi); } } #if !BB_MMU typedef struct nommu_save_t { char **new_env; char **old_env; char **argv; } nommu_save_t; #else #define pseudo_exec_argv(nommu_save, argv, assignment_cnt, argv_expanded) \ pseudo_exec_argv(argv, assignment_cnt, argv_expanded) #define pseudo_exec(nommu_save, command, argv_expanded) \ pseudo_exec(command, argv_expanded) #endif /* Called after [v]fork() in run_pipe(), or from builtin_exec(). * Never returns. * XXX no exit() here. If you don't exec, use _exit instead. * The at_exit handlers apparently confuse the calling process, * in particular stdin handling. Not sure why? -- because of vfork! (vda) */ static void pseudo_exec_argv(nommu_save_t *nommu_save, char **argv, int assignment_cnt, char **argv_expanded) NORETURN; static void pseudo_exec_argv(nommu_save_t *nommu_save, char **argv, int assignment_cnt, char **argv_expanded) { char **new_env; /* Case when we are here: ... | var=val | ... */ if (!argv[assignment_cnt]) _exit(EXIT_SUCCESS); new_env = expand_assignments(argv, assignment_cnt); #if BB_MMU putenv_all(new_env); free(new_env); /* optional */ #else nommu_save->new_env = new_env; nommu_save->old_env = putenv_all_and_save_old(new_env); #endif if (argv_expanded) { argv = argv_expanded; } else { argv = expand_strvec_to_strvec(argv + assignment_cnt); #if !BB_MMU nommu_save->argv = argv; #endif } /* On NOMMU, we must never block! * Example: { sleep 99999 | read line } & echo Ok * read builtin will block on read syscall, leaving parent blocked * in vfork. Therefore we can't do this: */ #if BB_MMU /* Check if the command matches any of the builtins. * Depending on context, this might be redundant. But it's * easier to waste a few CPU cycles than it is to figure out * if this is one of those cases. */ { int rcode; const struct built_in_command *x; for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) { if (strcmp(argv[0], x->cmd) == 0) { debug_printf_exec("running builtin '%s'\n", argv[0]); rcode = x->function(argv); fflush(NULL); _exit(rcode); } } } #endif #if ENABLE_FEATURE_SH_STANDALONE /* Check if the command matches any busybox applets */ if (strchr(argv[0], '/') == NULL) { int a = find_applet_by_name(argv[0]); if (a >= 0) { #if BB_MMU /* see above why on NOMMU it is not allowed */ if (APPLET_IS_NOEXEC(a)) { debug_printf_exec("running applet '%s'\n", argv[0]); run_applet_no_and_exit(a, argv); } #endif /* Re-exec ourselves */ debug_printf_exec("re-execing applet '%s'\n", argv[0]); sigprocmask(SIG_SETMASK, &G.inherited_set, NULL); execv(bb_busybox_exec_path, argv); /* If they called chroot or otherwise made the binary no longer * executable, fall through */ } } #endif debug_printf_exec("execing '%s'\n", argv[0]); sigprocmask(SIG_SETMASK, &G.inherited_set, NULL); execvp(argv[0], argv); bb_perror_msg("can't exec '%s'", argv[0]); _exit(EXIT_FAILURE); } #if BB_MMU static void reset_traps_to_defaults(void) { unsigned sig; int dirty; if (!G.traps) return; dirty = 0; for (sig = 0; sig < NSIG; sig++) { if (!G.traps[sig]) continue; free(G.traps[sig]); G.traps[sig] = NULL; /* There is no signal for 0 (EXIT) */ if (sig == 0) continue; /* there was a trap handler, we are removing it * (if sig has non-DFL handling, * we don't need to do anything) */ if (sig < 32 && (G.non_DFL_mask & (1 << sig))) continue; sigdelset(&G.blocked_set, sig); dirty = 1; } if (dirty) sigprocmask(SIG_SETMASK, &G.blocked_set, NULL); } #define clean_up_after_re_execute() ((void)0) #else /* !BB_MMU */ static void re_execute_shell(const char *s) NORETURN; static void re_execute_shell(const char *s) { struct variable *cur; char **argv, **pp, **pp2; unsigned cnt; /* 1:hush 2:-$ 3:-! 4:-? 5:-D * 6:-c 7: 8:NULL */ cnt = 8 + G.global_argc; for (cur = G.top_var; cur; cur = cur->next) { if (!cur->flg_export || cur->flg_read_only) cnt += 2; } G.argv_from_re_execing = pp = xzalloc(sizeof(argv[0]) * cnt); *pp++ = (char *) G.argv0_for_re_execing; *pp++ = xasprintf("-$%u", (unsigned) G.root_pid); *pp++ = xasprintf("-!%u", (unsigned) G.last_bg_pid); *pp++ = xasprintf("-?%u", (unsigned) G.last_return_code); #if ENABLE_HUSH_LOOPS *pp++ = xasprintf("-D%u", G.depth_of_loop); #endif for (cur = G.top_var; cur; cur = cur->next) { if (cur->varstr == hush_version_str) continue; if (cur->flg_read_only) { *pp++ = (char *) "-R"; *pp++ = cur->varstr; } else if (!cur->flg_export) { *pp++ = (char *) "-V"; *pp++ = cur->varstr; } } //TODO: pass functions /* We can pass activated traps here. Say, -Tnn:trap_string * * However, POSIX says that subshells reset signals with traps * to SIG_DFL. * I tested bash-3.2 and it not only does that with true subshells * of the form ( list ), but with any forked children shells. * I set trap "echo W" WINCH; and then tried: * * { echo 1; sleep 20; echo 2; } & * while true; do echo 1; sleep 20; echo 2; break; done & * true | { echo 1; sleep 20; echo 2; } | cat * * In all these cases sending SIGWINCH to the child shell * did not run the trap. If I add trap "echo V" WINCH; * _inside_ group (just before echo 1), it works. * * I conclude it means we don't need to pass active traps here. * exec syscall below resets them to SIG_DFL for us. */ *pp++ = (char *) "-c"; *pp++ = (char *) s; pp2 = G.global_argv; while (*pp2) *pp++ = *pp2++; /* *pp = NULL; - is already there */ debug_printf_exec("re_execute_shell pid:%d cmd:'%s'\n", getpid(), s); sigprocmask(SIG_SETMASK, &G.inherited_set, NULL); execv(bb_busybox_exec_path, G.argv_from_re_execing); /* Fallback. Useful for init=/bin/hush usage etc */ if (G.argv0_for_re_execing[0] == '/') execv(G.argv0_for_re_execing, G.argv_from_re_execing); xfunc_error_retval = 127; bb_error_msg_and_die("can't re-execute the shell"); } static void clean_up_after_re_execute(void) { char **pp = G.argv_from_re_execing; if (pp) { /* Must match re_execute_shell's allocations */ free(pp[1]); free(pp[2]); free(pp[3]); #if ENABLE_HUSH_LOOPS free(pp[4]); #endif free(pp); G.argv_from_re_execing = NULL; } } #endif static int run_list(struct pipe *pi); /* Called after [v]fork() in run_pipe() */ static void pseudo_exec(nommu_save_t *nommu_save, struct command *command, char **argv_expanded) NORETURN; static void pseudo_exec(nommu_save_t *nommu_save, struct command *command, char **argv_expanded) { if (command->argv) { pseudo_exec_argv(nommu_save, command->argv, command->assignment_cnt, argv_expanded); } if (command->group) { /* Cases when we are here: * ( list ) * { list } & * ... | ( list ) | ... * ... | { list } | ... */ #if BB_MMU int rcode; debug_printf_exec("pseudo_exec: run_list\n"); reset_traps_to_defaults(); rcode = run_list(command->group); /* OK to leak memory by not calling free_pipe_list, * since this process is about to exit */ _exit(rcode); #else re_execute_shell(command->group_as_string); #endif } /* Case when we are here: ... | >file */ debug_printf_exec("pseudo_exec'ed null command\n"); _exit(EXIT_SUCCESS); } #if ENABLE_HUSH_JOB static const char *get_cmdtext(struct pipe *pi) { char **argv; char *p; int len; /* This is subtle. ->cmdtext is created only on first backgrounding. * (Think "cat, , fg, , fg, ...." here...) * On subsequent bg argv is trashed, but we won't use it */ if (pi->cmdtext) return pi->cmdtext; argv = pi->cmds[0].argv; if (!argv || !argv[0]) { pi->cmdtext = xzalloc(1); return pi->cmdtext; } len = 0; do len += strlen(*argv) + 1; while (*++argv); pi->cmdtext = p = xmalloc(len); argv = pi->cmds[0].argv; do { len = strlen(*argv); memcpy(p, *argv, len); p += len; *p++ = ' '; } while (*++argv); p[-1] = '\0'; return pi->cmdtext; } static void insert_bg_job(struct pipe *pi) { struct pipe *thejob; int i; /* Linear search for the ID of the job to use */ pi->jobid = 1; for (thejob = G.job_list; thejob; thejob = thejob->next) if (thejob->jobid >= pi->jobid) pi->jobid = thejob->jobid + 1; /* Add thejob to the list of running jobs */ if (!G.job_list) { thejob = G.job_list = xmalloc(sizeof(*thejob)); } else { for (thejob = G.job_list; thejob->next; thejob = thejob->next) continue; thejob->next = xmalloc(sizeof(*thejob)); thejob = thejob->next; } /* Physically copy the struct job */ memcpy(thejob, pi, sizeof(struct pipe)); thejob->cmds = xzalloc(sizeof(pi->cmds[0]) * pi->num_cmds); /* We cannot copy entire pi->cmds[] vector! Double free()s will happen */ for (i = 0; i < pi->num_cmds; i++) { // TODO: do we really need to have so many fields which are just dead weight // at execution stage? thejob->cmds[i].pid = pi->cmds[i].pid; /* all other fields are not used and stay zero */ } thejob->next = NULL; thejob->cmdtext = xstrdup(get_cmdtext(pi)); /* We don't wait for background thejobs to return -- append it to the list of backgrounded thejobs and leave it alone */ if (G_interactive_fd) printf("[%d] %d %s\n", thejob->jobid, thejob->cmds[0].pid, thejob->cmdtext); G.last_bg_pid = thejob->cmds[0].pid; G.last_jobid = thejob->jobid; } static void remove_bg_job(struct pipe *pi) { struct pipe *prev_pipe; if (pi == G.job_list) { G.job_list = pi->next; } else { prev_pipe = G.job_list; while (prev_pipe->next != pi) prev_pipe = prev_pipe->next; prev_pipe->next = pi->next; } if (G.job_list) G.last_jobid = G.job_list->jobid; else G.last_jobid = 0; } /* Remove a backgrounded job */ static void delete_finished_bg_job(struct pipe *pi) { remove_bg_job(pi); pi->stopped_cmds = 0; free_pipe(pi, 0); free(pi); } #endif /* JOB */ /* Check to see if any processes have exited -- if they * have, figure out why and see if a job has completed */ static int checkjobs(struct pipe* fg_pipe) { int attributes; int status; #if ENABLE_HUSH_JOB struct pipe *pi; #endif pid_t childpid; int rcode = 0; debug_printf_jobs("checkjobs %p\n", fg_pipe); errno = 0; // if (G.handled_SIGCHLD == G.count_SIGCHLD) // /* avoid doing syscall, nothing there anyway */ // return rcode; attributes = WUNTRACED; if (fg_pipe == NULL) attributes |= WNOHANG; /* Do we do this right? * bash-3.00# sleep 20 | false * * [3]+ Stopped sleep 20 | false * bash-3.00# echo $? * 1 <========== bg pipe is not fully done, but exitcode is already known! */ //FIXME: non-interactive bash does not continue even if all processes in fg pipe //are stopped. Testcase: "cat | cat" in a script (not on command line) // + killall -STOP cat wait_more: while (1) { int i; int dead; // i = G.count_SIGCHLD; childpid = waitpid(-1, &status, attributes); if (childpid <= 0) { if (childpid && errno != ECHILD) bb_perror_msg("waitpid"); // else /* Until next SIGCHLD, waitpid's are useless */ // G.handled_SIGCHLD = i; break; } dead = WIFEXITED(status) || WIFSIGNALED(status); #if DEBUG_JOBS if (WIFSTOPPED(status)) debug_printf_jobs("pid %d stopped by sig %d (exitcode %d)\n", childpid, WSTOPSIG(status), WEXITSTATUS(status)); if (WIFSIGNALED(status)) debug_printf_jobs("pid %d killed by sig %d (exitcode %d)\n", childpid, WTERMSIG(status), WEXITSTATUS(status)); if (WIFEXITED(status)) debug_printf_jobs("pid %d exited, exitcode %d\n", childpid, WEXITSTATUS(status)); #endif /* Were we asked to wait for fg pipe? */ if (fg_pipe) { for (i = 0; i < fg_pipe->num_cmds; i++) { debug_printf_jobs("check pid %d\n", fg_pipe->cmds[i].pid); if (fg_pipe->cmds[i].pid != childpid) continue; /* printf("process %d exit %d\n", i, WEXITSTATUS(status)); */ if (dead) { fg_pipe->cmds[i].pid = 0; fg_pipe->alive_cmds--; if (i == fg_pipe->num_cmds - 1) { /* last process gives overall exitstatus */ rcode = WEXITSTATUS(status); IF_HAS_KEYWORDS(if (fg_pipe->pi_inverted) rcode = !rcode;) } } else { fg_pipe->cmds[i].is_stopped = 1; fg_pipe->stopped_cmds++; } debug_printf_jobs("fg_pipe: alive_cmds %d stopped_cmds %d\n", fg_pipe->alive_cmds, fg_pipe->stopped_cmds); if (fg_pipe->alive_cmds - fg_pipe->stopped_cmds <= 0) { /* All processes in fg pipe have exited/stopped */ #if ENABLE_HUSH_JOB if (fg_pipe->alive_cmds) insert_bg_job(fg_pipe); #endif return rcode; } /* There are still running processes in the fg pipe */ goto wait_more; /* do waitpid again */ } /* it wasnt fg_pipe, look for process in bg pipes */ } #if ENABLE_HUSH_JOB /* We asked to wait for bg or orphaned children */ /* No need to remember exitcode in this case */ for (pi = G.job_list; pi; pi = pi->next) { for (i = 0; i < pi->num_cmds; i++) { if (pi->cmds[i].pid == childpid) goto found_pi_and_prognum; } } /* Happens when shell is used as init process (init=/bin/sh) */ debug_printf("checkjobs: pid %d was not in our list!\n", childpid); continue; /* do waitpid again */ found_pi_and_prognum: if (dead) { /* child exited */ pi->cmds[i].pid = 0; pi->alive_cmds--; if (!pi->alive_cmds) { if (G_interactive_fd) printf(JOB_STATUS_FORMAT, pi->jobid, "Done", pi->cmdtext); delete_finished_bg_job(pi); } } else { /* child stopped */ pi->cmds[i].is_stopped = 1; pi->stopped_cmds++; } #endif } /* while (waitpid succeeds)... */ return rcode; } #if ENABLE_HUSH_JOB static int checkjobs_and_fg_shell(struct pipe* fg_pipe) { pid_t p; int rcode = checkjobs(fg_pipe); /* Job finished, move the shell to the foreground */ p = getpgid(0); /* pgid of our process */ debug_printf_jobs("fg'ing ourself: getpgid(0)=%d\n", (int)p); tcsetpgrp(G_interactive_fd, p); return rcode; } #endif /* Start all the jobs, but don't wait for anything to finish. * See checkjobs(). * * Return code is normally -1, when the caller has to wait for children * to finish to determine the exit status of the pipe. If the pipe * is a simple builtin command, however, the action is done by the * time run_pipe returns, and the exit code is provided as the * return value. * * Returns -1 only if started some children. IOW: we have to * mask out retvals of builtins etc with 0xff! * * The only case when we do not need to [v]fork is when the pipe * is single, non-backgrounded, non-subshell command. Examples: * cmd ; ... { list } ; ... * cmd && ... { list } && ... * cmd || ... { list } || ... * If it is, then we can run cmd as a builtin, NOFORK [do we do this?], * or (if SH_STANDALONE) an applet, and we can run the { list } * with run_list(). If it isn't one of these, we fork and exec cmd. * * Cases when we must fork: * non-single: cmd | cmd * backgrounded: cmd & { list } & * subshell: ( list ) [&] */ static int run_pipe(struct pipe *pi) { static const char *const null_ptr = NULL; int i; int nextin; int pipefds[2]; /* pipefds[0] is for reading */ struct command *command; char **argv_expanded; char **argv; char *p; /* it is not always needed, but we aim to smaller code */ int squirrel[] = { -1, -1, -1 }; int rcode; debug_printf_exec("run_pipe start: members:%d\n", pi->num_cmds); USE_HUSH_JOB(pi->pgrp = -1;) pi->stopped_cmds = 0; command = &(pi->cmds[0]); argv_expanded = NULL; if (pi->num_cmds != 1 || pi->followup == PIPE_BG || command->grp_type == GRP_SUBSHELL ) { goto must_fork; } pi->alive_cmds = 1; debug_printf_exec(": group:%p argv:'%s'\n", command->group, command->argv ? command->argv[0] : "NONE"); if (command->group) { #if ENABLE_HUSH_FUNCTIONS if (command->grp_type == GRP_FUNCTION) { /* func () { list } */ bb_error_msg("here we ought to remember function definition, and go on"); return EXIT_SUCCESS; } #endif /* { list } */ debug_printf("non-subshell group\n"); setup_redirects(command, squirrel); debug_printf_exec(": run_list\n"); rcode = run_list(command->group) & 0xff; restore_redirects(squirrel); debug_printf_exec("run_pipe return %d\n", rcode); IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;) return rcode; } argv = command->argv ? command->argv : (char **) &null_ptr; { const struct built_in_command *x; char **new_env = NULL; char **old_env = NULL; if (argv[command->assignment_cnt] == NULL) { /* Assignments, but no command */ /* Ensure redirects take effect. Try "a=t >file" */ setup_redirects(command, squirrel); restore_redirects(squirrel); /* Set shell variables */ while (*argv) { p = expand_string_to_string(*argv); debug_printf_exec("set shell var:'%s'->'%s'\n", *argv, p); set_local_var(p, 0, 0); argv++; } /* Do we need to flag set_local_var() errors? * "assignment to readonly var" and "putenv error" */ return EXIT_SUCCESS; } /* Expand the rest into (possibly) many strings each */ argv_expanded = expand_strvec_to_strvec(argv + command->assignment_cnt); for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) { if (strcmp(argv_expanded[0], x->cmd) != 0) continue; if (x->function == builtin_exec && argv_expanded[1] == NULL) { debug_printf("exec with redirects only\n"); setup_redirects(command, NULL); rcode = EXIT_SUCCESS; goto clean_up_and_ret1; } debug_printf("builtin inline %s\n", argv_expanded[0]); /* XXX setup_redirects acts on file descriptors, not FILEs. * This is perfect for work that comes after exec(). * Is it really safe for inline use? Experimentally, * things seem to work with glibc. */ setup_redirects(command, squirrel); new_env = expand_assignments(argv, command->assignment_cnt); old_env = putenv_all_and_save_old(new_env); debug_printf_exec(": builtin '%s' '%s'...\n", x->cmd, argv_expanded[1]); rcode = x->function(argv_expanded) & 0xff; #if ENABLE_FEATURE_SH_STANDALONE clean_up_and_ret: #endif restore_redirects(squirrel); free_strings_and_unsetenv(new_env, 1); putenv_all(old_env); free(old_env); /* not free_strings()! */ clean_up_and_ret1: free(argv_expanded); IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;) debug_printf_exec("run_pipe return %d\n", rcode); return rcode; } #if ENABLE_FEATURE_SH_STANDALONE i = find_applet_by_name(argv_expanded[0]); if (i >= 0 && APPLET_IS_NOFORK(i)) { setup_redirects(command, squirrel); save_nofork_data(&G.nofork_save); new_env = expand_assignments(argv, command->assignment_cnt); old_env = putenv_all_and_save_old(new_env); debug_printf_exec(": run_nofork_applet '%s' '%s'...\n", argv_expanded[0], argv_expanded[1]); rcode = run_nofork_applet_prime(&G.nofork_save, i, argv_expanded); goto clean_up_and_ret; } #endif /* It is neither builtin nor applet. We must fork. */ } must_fork: /* NB: argv_expanded may already be created, and that * might include `cmd` runs! Do not rerun it! We *must* * use argv_expanded if it's non-NULL */ /* Going to fork a child per each pipe member */ pi->alive_cmds = 0; nextin = 0; for (i = 0; i < pi->num_cmds; i++) { #if !BB_MMU volatile nommu_save_t nommu_save; nommu_save.new_env = NULL; nommu_save.old_env = NULL; nommu_save.argv = NULL; #endif command = &(pi->cmds[i]); if (command->argv) { debug_printf_exec(": pipe member '%s' '%s'...\n", command->argv[0], command->argv[1]); } else { debug_printf_exec(": pipe member with no argv\n"); } /* pipes are inserted between pairs of commands */ pipefds[0] = 0; pipefds[1] = 1; if ((i + 1) < pi->num_cmds) xpipe(pipefds); command->pid = BB_MMU ? fork() : vfork(); if (!command->pid) { /* child */ #if ENABLE_HUSH_JOB die_sleep = 0; /* do not restore tty pgrp on xfunc death */ /* Every child adds itself to new process group * with pgid == pid_of_first_child_in_pipe */ if (G.run_list_level == 1 && G_interactive_fd) { pid_t pgrp; pgrp = pi->pgrp; if (pgrp < 0) /* true for 1st process only */ pgrp = getpid(); if (setpgid(0, pgrp) == 0 && pi->followup != PIPE_BG) { /* We do it in *every* child, not just first, * to avoid races */ tcsetpgrp(G_interactive_fd, pgrp); } } #endif xmove_fd(nextin, 0); xmove_fd(pipefds[1], 1); /* write end */ if (pipefds[0] > 1) close(pipefds[0]); /* read end */ /* Like bash, explicit redirects override pipes, * and the pipe fd is available for dup'ing. */ setup_redirects(command, NULL); /* Restore default handlers just prior to exec */ /*signal(SIGCHLD, SIG_DFL); - so far we don't have any handlers */ /* Stores to nommu_save list of env vars putenv'ed * (NOMMU, on MMU we don't need that) */ /* cast away volatility... */ pseudo_exec((nommu_save_t*) &nommu_save, command, argv_expanded); /* pseudo_exec() does not return */ } /* parent or error */ #if ENABLE_HUSH_JOB die_sleep = -1; /* restore tty pgrp on xfunc death */ #endif #if !BB_MMU /* Clean up after vforked child */ clean_up_after_re_execute(); free(nommu_save.argv); free_strings_and_unsetenv(nommu_save.new_env, 1); putenv_all(nommu_save.old_env); #endif free(argv_expanded); argv_expanded = NULL; if (command->pid < 0) { /* [v]fork failed */ /* Clearly indicate, was it fork or vfork */ bb_perror_msg(BB_MMU ? "fork" : "vfork"); } else { pi->alive_cmds++; #if ENABLE_HUSH_JOB /* Second and next children need to know pid of first one */ if (pi->pgrp < 0) pi->pgrp = command->pid; #endif } if (i) close(nextin); if ((i + 1) < pi->num_cmds) close(pipefds[1]); /* write end */ /* Pass read (output) pipe end to next iteration */ nextin = pipefds[0]; } if (!pi->alive_cmds) { debug_printf_exec("run_pipe return 1 (all forks failed, no children)\n"); return 1; } debug_printf_exec("run_pipe return -1 (%u children started)\n", pi->alive_cmds); return -1; } #ifndef debug_print_tree static void debug_print_tree(struct pipe *pi, int lvl) { static const char *const PIPE[] = { [PIPE_SEQ] = "SEQ", [PIPE_AND] = "AND", [PIPE_OR ] = "OR" , [PIPE_BG ] = "BG" , }; static const char *RES[] = { [RES_NONE ] = "NONE" , #if ENABLE_HUSH_IF [RES_IF ] = "IF" , [RES_THEN ] = "THEN" , [RES_ELIF ] = "ELIF" , [RES_ELSE ] = "ELSE" , [RES_FI ] = "FI" , #endif #if ENABLE_HUSH_LOOPS [RES_FOR ] = "FOR" , [RES_WHILE] = "WHILE", [RES_UNTIL] = "UNTIL", [RES_DO ] = "DO" , [RES_DONE ] = "DONE" , #endif #if ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE [RES_IN ] = "IN" , #endif #if ENABLE_HUSH_CASE [RES_CASE ] = "CASE" , [RES_MATCH] = "MATCH", [RES_CASEI] = "CASEI", [RES_ESAC ] = "ESAC" , #endif [RES_XXXX ] = "XXXX" , [RES_SNTX ] = "SNTX" , }; static const char *const GRPTYPE[] = { "{}", "()", #if ENABLE_HUSH_FUNCTIONS "func()", #endif }; int pin, prn; pin = 0; while (pi) { fprintf(stderr, "%*spipe %d res_word=%s followup=%d %s\n", lvl*2, "", pin, RES[pi->res_word], pi->followup, PIPE[pi->followup]); prn = 0; while (prn < pi->num_cmds) { struct command *command = &pi->cmds[prn]; char **argv = command->argv; fprintf(stderr, "%*s prog %d assignment_cnt:%d", lvl*2, "", prn, command->assignment_cnt); if (command->group) { fprintf(stderr, " group %s: (argv=%p)\n", GRPTYPE[command->grp_type], argv); debug_print_tree(command->group, lvl+1); prn++; continue; } if (argv) while (*argv) { fprintf(stderr, " '%s'", *argv); argv++; } fprintf(stderr, "\n"); prn++; } pi = pi->next; pin++; } } #endif /* NB: called by pseudo_exec, and therefore must not modify any * global data until exec/_exit (we can be a child after vfork!) */ static int run_list(struct pipe *pi) { #if ENABLE_HUSH_CASE char *case_word = NULL; #endif #if ENABLE_HUSH_LOOPS struct pipe *loop_top = NULL; char *for_varname = NULL; char **for_lcur = NULL; char **for_list = NULL; #endif smallint flag_skip = 1; smalluint rcode = 0; /* probably just for compiler */ #if ENABLE_HUSH_IF || ENABLE_HUSH_CASE smalluint cond_code = 0; #else enum { cond_code = 0, }; #endif /*enum reserved_style*/ smallint rword = RES_NONE; /*enum reserved_style*/ smallint skip_more_for_this_rword = RES_XXXX; debug_printf_exec("run_list start lvl %d\n", G.run_list_level + 1); #if ENABLE_HUSH_LOOPS /* Check syntax for "for" */ for (struct pipe *cpipe = pi; cpipe; cpipe = cpipe->next) { if (cpipe->res_word != RES_FOR && cpipe->res_word != RES_IN) continue; /* current word is FOR or IN (BOLD in comments below) */ if (cpipe->next == NULL) { syntax("malformed for"); debug_printf_exec("run_list lvl %d return 1\n", G.run_list_level); return 1; } /* "FOR v; do ..." and "for v IN a b; do..." are ok */ if (cpipe->next->res_word == RES_DO) continue; /* next word is not "do". It must be "in" then ("FOR v in ...") */ if (cpipe->res_word == RES_IN /* "for v IN a b; not_do..."? */ || cpipe->next->res_word != RES_IN /* FOR v not_do_and_not_in..."? */ ) { syntax("malformed for"); debug_printf_exec("run_list lvl %d return 1\n", G.run_list_level); return 1; } } #endif /* Past this point, all code paths should jump to ret: label * in order to return, no direct "return" statements please. * This helps to ensure that no memory is leaked. */ ////TODO: ctrl-Z handling needs re-thinking and re-testing #if ENABLE_HUSH_JOB /* Example of nested list: "while true; do { sleep 1 | exit 2; } done". * We are saving state before entering outermost list ("while...done") * so that ctrl-Z will correctly background _entire_ outermost list, * not just a part of it (like "sleep 1 | exit 2") */ if (++G.run_list_level == 1 && G_interactive_fd) { if (sigsetjmp(G.toplevel_jb, 1)) { /* ctrl-Z forked and we are parent; or ctrl-C. * Sighandler has longjmped us here */ signal(SIGINT, SIG_IGN); signal(SIGTSTP, SIG_IGN); /* Restore level (we can be coming from deep inside * nested levels) */ G.run_list_level = 1; #if ENABLE_FEATURE_SH_STANDALONE if (G.nofork_save.saved) { /* if save area is valid */ debug_printf_jobs("exiting nofork early\n"); restore_nofork_data(&G.nofork_save); } #endif //// if (G.ctrl_z_flag) { //// /* ctrl-Z has forked and stored pid of the child in pi->pid. //// * Remember this child as background job */ //// insert_bg_job(pi); //// } else { /* ctrl-C. We just stop doing whatever we were doing */ bb_putchar('\n'); //// } USE_HUSH_LOOPS(loop_top = NULL;) USE_HUSH_LOOPS(G.depth_of_loop = 0;) rcode = 0; goto ret; } //// /* ctrl-Z handler will store pid etc in pi */ //// G.toplevel_list = pi; //// G.ctrl_z_flag = 0; ////#if ENABLE_FEATURE_SH_STANDALONE //// G.nofork_save.saved = 0; /* in case we will run a nofork later */ ////#endif //// signal_SA_RESTART_empty_mask(SIGTSTP, handler_ctrl_z); //// signal(SIGINT, handler_ctrl_c); } #endif /* JOB */ /* Go through list of pipes, (maybe) executing them. */ for (; pi; pi = USE_HUSH_LOOPS(rword == RES_DONE ? loop_top : ) pi->next) { if (G.flag_SIGINT) break; IF_HAS_KEYWORDS(rword = pi->res_word;) IF_HAS_NO_KEYWORDS(rword = RES_NONE;) debug_printf_exec(": rword=%d cond_code=%d skip_more=%d\n", rword, cond_code, skip_more_for_this_rword); #if ENABLE_HUSH_LOOPS if ((rword == RES_WHILE || rword == RES_UNTIL || rword == RES_FOR) && loop_top == NULL /* avoid bumping G.depth_of_loop twice */ ) { /* start of a loop: remember where loop starts */ loop_top = pi; G.depth_of_loop++; } #endif if (rword == skip_more_for_this_rword && flag_skip) { if (pi->followup == PIPE_SEQ) flag_skip = 0; /* it is " && CMD" or " || CMD" * and we should not execute CMD */ continue; } flag_skip = 1; skip_more_for_this_rword = RES_XXXX; #if ENABLE_HUSH_IF if (cond_code) { if (rword == RES_THEN) { /* "if THEN cmd": skip cmd */ continue; } } else { if (rword == RES_ELSE || rword == RES_ELIF) { /* "if then ... ELSE/ELIF cmd": * skip cmd and all following ones */ break; } } #endif #if ENABLE_HUSH_LOOPS if (rword == RES_FOR) { /* && pi->num_cmds - always == 1 */ if (!for_lcur) { /* first loop through for */ static const char encoded_dollar_at[] ALIGN1 = { SPECIAL_VAR_SYMBOL, '@' | 0x80, SPECIAL_VAR_SYMBOL, '\0' }; /* encoded representation of "$@" */ static const char *const encoded_dollar_at_argv[] = { encoded_dollar_at, NULL }; /* argv list with one element: "$@" */ char **vals; vals = (char**)encoded_dollar_at_argv; if (pi->next->res_word == RES_IN) { /* if no variable values after "in" we skip "for" */ if (!pi->next->cmds[0].argv) break; vals = pi->next->cmds[0].argv; } /* else: "for var; do..." -> assume "$@" list */ /* create list of variable values */ debug_print_strings("for_list made from", vals); for_list = expand_strvec_to_strvec(vals); for_lcur = for_list; debug_print_strings("for_list", for_list); for_varname = pi->cmds[0].argv[0]; pi->cmds[0].argv[0] = NULL; } free(pi->cmds[0].argv[0]); if (!*for_lcur) { /* "for" loop is over, clean up */ free(for_list); for_list = NULL; for_lcur = NULL; pi->cmds[0].argv[0] = for_varname; break; } /* insert next value from for_lcur */ //TODO: does it need escaping? pi->cmds[0].argv[0] = xasprintf("%s=%s", for_varname, *for_lcur++); pi->cmds[0].assignment_cnt = 1; } if (rword == RES_IN) { continue; /* "for v IN list;..." - "in" has no cmds anyway */ } if (rword == RES_DONE) { continue; /* "done" has no cmds too */ } #endif #if ENABLE_HUSH_CASE if (rword == RES_CASE) { case_word = expand_strvec_to_string(pi->cmds->argv); continue; } if (rword == RES_MATCH) { char **argv; if (!case_word) /* "case ... matched_word) ... WORD)": we executed selected branch, stop */ break; /* all prev words didn't match, does this one match? */ argv = pi->cmds->argv; while (*argv) { char *pattern = expand_string_to_string(*argv); /* TODO: which FNM_xxx flags to use? */ cond_code = (fnmatch(pattern, case_word, /*flags:*/ 0) != 0); free(pattern); if (cond_code == 0) { /* match! we will execute this branch */ free(case_word); /* make future "word)" stop */ case_word = NULL; break; } argv++; } continue; } if (rword == RES_CASEI) { /* inside of a case branch */ if (cond_code != 0) continue; /* not matched yet, skip this pipe */ } #endif /* Just pressing in shell should check for jobs. * OTOH, in non-interactive shell this is useless * and only leads to extra job checks */ if (pi->num_cmds == 0) { if (G_interactive_fd) goto check_jobs_and_continue; continue; } /* After analyzing all keywords and conditions, we decided * to execute this pipe. NB: have to do checkjobs(NULL) * after run_pipe() to collect any background children, * even if list execution is to be stopped. */ debug_printf_exec(": run_pipe with %d members\n", pi->num_cmds); { int r; #if ENABLE_HUSH_LOOPS G.flag_break_continue = 0; #endif rcode = r = run_pipe(pi); /* NB: rcode is a smallint */ if (r != -1) { /* we only ran a builtin: rcode is already known * and we don't need to wait for anything. */ check_and_run_traps(0); #if ENABLE_HUSH_LOOPS /* was it "break" or "continue"? */ if (G.flag_break_continue) { smallint fbc = G.flag_break_continue; /* we might fall into outer *loop*, * don't want to break it too */ if (loop_top) { G.depth_break_continue--; if (G.depth_break_continue == 0) G.flag_break_continue = 0; /* else: e.g. "continue 2" should *break* once, *then* continue */ } /* else: "while... do... { we are here (innermost list is not a loop!) };...done" */ if (G.depth_break_continue != 0 || fbc == BC_BREAK) goto check_jobs_and_break; /* "continue": simulate end of loop */ rword = RES_DONE; continue; } #endif } else if (pi->followup == PIPE_BG) { /* what does bash do with attempts to background builtins? */ /* even bash 3.2 doesn't do that well with nested bg: * try "{ { sleep 10; echo DEEP; } & echo HERE; } &". * I'm NOT treating inner &'s as jobs */ check_and_run_traps(0); #if ENABLE_HUSH_JOB if (G.run_list_level == 1) insert_bg_job(pi); #endif rcode = 0; /* EXIT_SUCCESS */ } else { #if ENABLE_HUSH_JOB if (G.run_list_level == 1 && G_interactive_fd) { /* waits for completion, then fg's main shell */ rcode = checkjobs_and_fg_shell(pi); check_and_run_traps(0); debug_printf_exec(": checkjobs_and_fg_shell returned %d\n", rcode); } else #endif { /* this one just waits for completion */ rcode = checkjobs(pi); check_and_run_traps(0); debug_printf_exec(": checkjobs returned %d\n", rcode); } } } debug_printf_exec(": setting last_return_code=%d\n", rcode); G.last_return_code = rcode; /* Analyze how result affects subsequent commands */ #if ENABLE_HUSH_IF if (rword == RES_IF || rword == RES_ELIF) cond_code = rcode; #endif #if ENABLE_HUSH_LOOPS if (rword == RES_WHILE) { if (rcode) { rcode = 0; /* "while false; do...done" - exitcode 0 */ goto check_jobs_and_break; } } if (rword == RES_UNTIL) { if (!rcode) { check_jobs_and_break: checkjobs(NULL); break; } } #endif if ((rcode == 0 && pi->followup == PIPE_OR) || (rcode != 0 && pi->followup == PIPE_AND) ) { skip_more_for_this_rword = rword; } check_jobs_and_continue: checkjobs(NULL); } /* for (pi) */ #if ENABLE_HUSH_JOB //// if (G.ctrl_z_flag) { //// /* ctrl-Z forked somewhere in the past, we are the child, //// * and now we completed running the list. Exit. */ //////TODO: _exit? //// exit(rcode); //// } ret: G.run_list_level--; //// if (!G.run_list_level && G_interactive_fd) { //// signal(SIGTSTP, SIG_IGN); //// signal(SIGINT, SIG_IGN); //// } #endif debug_printf_exec("run_list lvl %d return %d\n", G.run_list_level + 1, rcode); #if ENABLE_HUSH_LOOPS if (loop_top) G.depth_of_loop--; free(for_list); #endif #if ENABLE_HUSH_CASE free(case_word); #endif return rcode; } /* Select which version we will use */ static int run_and_free_list(struct pipe *pi) { int rcode = 0; debug_printf_exec("run_and_free_list entered\n"); if (!G.fake_mode) { debug_printf_exec(": run_list with %d members\n", pi->num_cmds); rcode = run_list(pi); } /* free_pipe_list has the side effect of clearing memory. * In the long run that function can be merged with run_list, * but doing that now would hobble the debugging effort. */ free_pipe_list(pi, /* indent: */ 0); debug_printf_exec("run_and_free_list return %d\n", rcode); return rcode; } /* Peek ahead in the in_str to find out if we have a "&n" construct, * as in "2>&1", that represents duplicating a file descriptor. * Return either -2 (syntax error), -1 (no &), or the number found. */ static int redirect_dup_num(struct in_str *input) { int ch, d = 0, ok = 0; ch = i_peek(input); if (ch != '&') return -1; i_getch(input); /* get the & */ ch = i_peek(input); if (ch == '-') { i_getch(input); return -3; /* "-" represents "close me" */ } while (isdigit(ch)) { d = d*10 + (ch-'0'); ok = 1; i_getch(input); ch = i_peek(input); } if (ok) return d; bb_error_msg("ambiguous redirect"); return -2; } /* The src parameter allows us to peek forward to a possible &n syntax * for file descriptor duplication, e.g., "2>&1". * Return code is 0 normally, 1 if a syntax error is detected in src. * Resource errors (in xmalloc) cause the process to exit */ static int setup_redirect(struct parse_context *ctx, int fd, redir_type style, struct in_str *input) { struct command *command = ctx->command; struct redir_struct *redir; struct redir_struct **redirp; int dup_num; /* Check for a '2>&1' type redirect */ dup_num = redirect_dup_num(input); if (dup_num == -2) return 1; /* syntax error */ /* Create a new redir_struct and drop it onto the end of the linked list */ redirp = &command->redirects; while ((redir = *redirp) != NULL) { redirp = &(redir->next); } *redirp = redir = xzalloc(sizeof(*redir)); /* redir->next = NULL; */ /* redir->rd_filename = NULL; */ redir->rd_type = style; redir->fd = (fd == -1) ? redir_table[style].default_fd : fd; debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip); redir->dup = dup_num; if (dup_num != -1) { /* Erik had a check here that the file descriptor in question * is legit; I postpone that to "run time" * A "-" representation of "close me" shows up as a -3 here */ debug_printf("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup); } else { /* We do _not_ try to open the file that src points to, * since we need to return and let src be expanded first. * Set ctx->pending_redirect, so we know what to do at the * end of the next parsed word. */ ctx->pending_redirect = redir; } return 0; } static struct pipe *new_pipe(void) { struct pipe *pi; pi = xzalloc(sizeof(struct pipe)); /*pi->followup = 0; - deliberately invalid value */ /*pi->res_word = RES_NONE; - RES_NONE is 0 anyway */ return pi; } /* Command (member of a pipe) is complete. The only possible error here * is out of memory, in which case xmalloc exits. */ static int done_command(struct parse_context *ctx) { /* The command is really already in the pipe structure, so * advance the pipe counter and make a new, null command. */ struct pipe *pi = ctx->pipe; struct command *command = ctx->command; if (command) { if (command->group == NULL && command->argv == NULL && command->redirects == NULL ) { debug_printf_parse("done_command: skipping null cmd, num_cmds=%d\n", pi->num_cmds); return pi->num_cmds; } pi->num_cmds++; debug_printf_parse("done_command: ++num_cmds=%d\n", pi->num_cmds); } else { debug_printf_parse("done_command: initializing, num_cmds=%d\n", pi->num_cmds); } /* Only real trickiness here is that the uncommitted * command structure is not counted in pi->num_cmds. */ pi->cmds = xrealloc(pi->cmds, sizeof(*pi->cmds) * (pi->num_cmds+1)); command = &pi->cmds[pi->num_cmds]; memset(command, 0, sizeof(*command)); ctx->command = command; /* but ctx->pipe and ctx->list_head remain unchanged */ return pi->num_cmds; /* used only for 0/nonzero check */ } static void done_pipe(struct parse_context *ctx, pipe_style type) { int not_null; debug_printf_parse("done_pipe entered, followup %d\n", type); /* Close previous command */ not_null = done_command(ctx); ctx->pipe->followup = type; IF_HAS_KEYWORDS(ctx->pipe->pi_inverted = ctx->ctx_inverted;) IF_HAS_KEYWORDS(ctx->ctx_inverted = 0;) IF_HAS_KEYWORDS(ctx->pipe->res_word = ctx->ctx_res_w;) /* Without this check, even just on command line generates * tree of three NOPs (!). Which is harmless but annoying. * IOW: it is safe to do it unconditionally. * RES_NONE case is for "for a in; do ..." (empty IN set) * to work, possibly other cases too. */ if (not_null IF_HAS_KEYWORDS(|| ctx->ctx_res_w != RES_NONE)) { struct pipe *new_p; debug_printf_parse("done_pipe: adding new pipe: " "not_null:%d ctx->ctx_res_w:%d\n", not_null, ctx->ctx_res_w); new_p = new_pipe(); ctx->pipe->next = new_p; ctx->pipe = new_p; /* RES_THEN, RES_DO etc are "sticky" - * they remain set for commands inside if/while. * This is used to control execution. * RES_FOR and RES_IN are NOT sticky (needed to support * cases where variable or value happens to match a keyword): */ #if ENABLE_HUSH_LOOPS if (ctx->ctx_res_w == RES_FOR || ctx->ctx_res_w == RES_IN) ctx->ctx_res_w = RES_NONE; #endif #if ENABLE_HUSH_CASE if (ctx->ctx_res_w == RES_MATCH) ctx->ctx_res_w = RES_CASEI; #endif ctx->command = NULL; /* trick done_command below */ /* Create the memory for command, roughly: * ctx->pipe->cmds = new struct command; * ctx->command = &ctx->pipe->cmds[0]; */ done_command(ctx); } debug_printf_parse("done_pipe return\n"); } static void initialize_context(struct parse_context *ctx) { memset(ctx, 0, sizeof(*ctx)); ctx->pipe = ctx->list_head = new_pipe(); /* Create the memory for command, roughly: * ctx->pipe->cmds = new struct command; * ctx->command = &ctx->pipe->cmds[0]; */ done_command(ctx); } /* If a reserved word is found and processed, parse context is modified * and 1 is returned. */ #if HAS_KEYWORDS struct reserved_combo { char literal[6]; unsigned char res; unsigned char assignment_flag; int flag; }; enum { FLAG_END = (1 << RES_NONE ), #if ENABLE_HUSH_IF FLAG_IF = (1 << RES_IF ), FLAG_THEN = (1 << RES_THEN ), FLAG_ELIF = (1 << RES_ELIF ), FLAG_ELSE = (1 << RES_ELSE ), FLAG_FI = (1 << RES_FI ), #endif #if ENABLE_HUSH_LOOPS FLAG_FOR = (1 << RES_FOR ), FLAG_WHILE = (1 << RES_WHILE), FLAG_UNTIL = (1 << RES_UNTIL), FLAG_DO = (1 << RES_DO ), FLAG_DONE = (1 << RES_DONE ), FLAG_IN = (1 << RES_IN ), #endif #if ENABLE_HUSH_CASE FLAG_MATCH = (1 << RES_MATCH), FLAG_ESAC = (1 << RES_ESAC ), #endif FLAG_START = (1 << RES_XXXX ), }; static const struct reserved_combo* match_reserved_word(o_string *word) { /* Mostly a list of accepted follow-up reserved words. * FLAG_END means we are done with the sequence, and are ready * to turn the compound list into a command. * FLAG_START means the word must start a new compound list. */ static const struct reserved_combo reserved_list[] = { #if ENABLE_HUSH_IF { "!", RES_NONE, NOT_ASSIGNMENT , 0 }, { "if", RES_IF, WORD_IS_KEYWORD, FLAG_THEN | FLAG_START }, { "then", RES_THEN, WORD_IS_KEYWORD, FLAG_ELIF | FLAG_ELSE | FLAG_FI }, { "elif", RES_ELIF, WORD_IS_KEYWORD, FLAG_THEN }, { "else", RES_ELSE, WORD_IS_KEYWORD, FLAG_FI }, { "fi", RES_FI, NOT_ASSIGNMENT , FLAG_END }, #endif #if ENABLE_HUSH_LOOPS { "for", RES_FOR, NOT_ASSIGNMENT , FLAG_IN | FLAG_DO | FLAG_START }, { "while", RES_WHILE, WORD_IS_KEYWORD, FLAG_DO | FLAG_START }, { "until", RES_UNTIL, WORD_IS_KEYWORD, FLAG_DO | FLAG_START }, { "in", RES_IN, NOT_ASSIGNMENT , FLAG_DO }, { "do", RES_DO, WORD_IS_KEYWORD, FLAG_DONE }, { "done", RES_DONE, NOT_ASSIGNMENT , FLAG_END }, #endif #if ENABLE_HUSH_CASE { "case", RES_CASE, NOT_ASSIGNMENT , FLAG_MATCH | FLAG_START }, { "esac", RES_ESAC, NOT_ASSIGNMENT , FLAG_END }, #endif }; const struct reserved_combo *r; for (r = reserved_list; r < reserved_list + ARRAY_SIZE(reserved_list); r++) { if (strcmp(word->data, r->literal) == 0) return r; } return NULL; } static int reserved_word(o_string *word, struct parse_context *ctx) { #if ENABLE_HUSH_CASE static const struct reserved_combo reserved_match = { "", RES_MATCH, NOT_ASSIGNMENT , FLAG_MATCH | FLAG_ESAC }; #endif const struct reserved_combo *r; r = match_reserved_word(word); if (!r) return 0; debug_printf("found reserved word %s, res %d\n", r->literal, r->res); #if ENABLE_HUSH_CASE if (r->res == RES_IN && ctx->ctx_res_w == RES_CASE) /* "case word IN ..." - IN part starts first match part */ r = &reserved_match; else #endif if (r->flag == 0) { /* '!' */ if (ctx->ctx_inverted) { /* bash doesn't accept '! ! true' */ syntax("! ! command"); IF_HAS_KEYWORDS(ctx->ctx_res_w = RES_SNTX;) } ctx->ctx_inverted = 1; return 1; } if (r->flag & FLAG_START) { struct parse_context *old; old = xmalloc(sizeof(*old)); debug_printf_parse("push stack %p\n", old); *old = *ctx; /* physical copy */ initialize_context(ctx); ctx->stack = old; } else if (/*ctx->ctx_res_w == RES_NONE ||*/ !(ctx->old_flag & (1 << r->res))) { syntax(word->data); ctx->ctx_res_w = RES_SNTX; return 1; } ctx->ctx_res_w = r->res; ctx->old_flag = r->flag; if (ctx->old_flag & FLAG_END) { struct parse_context *old; done_pipe(ctx, PIPE_SEQ); debug_printf_parse("pop stack %p\n", ctx->stack); old = ctx->stack; old->command->group = ctx->list_head; old->command->grp_type = GRP_NORMAL; #if !BB_MMU o_addstr(&old->as_string, ctx->as_string.data); o_free_unsafe(&ctx->as_string); old->command->group_as_string = xstrdup(old->as_string.data); debug_printf_parse("pop, remembering as:'%s'\n", old->command->group_as_string); #endif *ctx = *old; /* physical copy */ free(old); } word->o_assignment = r->assignment_flag; return 1; } #endif /* Word is complete, look at it and update parsing context. * Normal return is 0. Syntax errors return 1. * Note: on return, word is reset, but not o_free'd! */ static int done_word(o_string *word, struct parse_context *ctx) { struct command *command = ctx->command; debug_printf_parse("done_word entered: '%s' %p\n", word->data, command); if (word->length == 0 && word->nonnull == 0) { debug_printf_parse("done_word return 0: true null, ignored\n"); return 0; } /* If this word wasn't an assignment, next ones definitely * can't be assignments. Even if they look like ones. */ if (word->o_assignment != DEFINITELY_ASSIGNMENT && word->o_assignment != WORD_IS_KEYWORD ) { word->o_assignment = NOT_ASSIGNMENT; } else { if (word->o_assignment == DEFINITELY_ASSIGNMENT) command->assignment_cnt++; word->o_assignment = MAYBE_ASSIGNMENT; } if (ctx->pending_redirect) { /* We do not glob in e.g. >*.tmp case. bash seems to glob here * only if run as "bash", not "sh" */ ctx->pending_redirect->rd_filename = xstrdup(word->data); word->o_assignment = NOT_ASSIGNMENT; debug_printf("word stored in rd_filename: '%s'\n", word->data); } else { /* "{ echo foo; } echo bar" - bad */ /* NB: bash allows e.g.: * if true; then { echo foo; } fi * while if false; then false; fi do break; done * TODO? */ if (command->group) { syntax(word->data); debug_printf_parse("done_word return 1: syntax error, " "groups and arglists don't mix\n"); return 1; } #if HAS_KEYWORDS #if ENABLE_HUSH_CASE if (ctx->ctx_dsemicolon && strcmp(word->data, "esac") != 0 /* not "... pattern) cmd;; esac" */ ) { /* already done when ctx_dsemicolon was set to 1: */ /* ctx->ctx_res_w = RES_MATCH; */ ctx->ctx_dsemicolon = 0; } else #endif if (!command->argv /* if it's the first word... */ #if ENABLE_HUSH_LOOPS && ctx->ctx_res_w != RES_FOR /* ...not after FOR or IN */ && ctx->ctx_res_w != RES_IN #endif ) { debug_printf_parse(": checking '%s' for reserved-ness\n", word->data); if (reserved_word(word, ctx)) { o_reset(word); debug_printf_parse("done_word return %d\n", (ctx->ctx_res_w == RES_SNTX)); return (ctx->ctx_res_w == RES_SNTX); } } #endif if (word->nonnull /* word had "xx" or 'xx' at least as part of it. */ /* optimization: and if it's ("" or '') or ($v... or `cmd`...): */ && (word->data[0] == '\0' || word->data[0] == SPECIAL_VAR_SYMBOL) /* (otherwise it's known to be not empty and is already safe) */ ) { /* exclude "$@" - it can expand to no word despite "" */ char *p = word->data; while (p[0] == SPECIAL_VAR_SYMBOL && (p[1] & 0x7f) == '@' && p[2] == SPECIAL_VAR_SYMBOL ) { p += 3; } if (p == word->data || p[0] != '\0') { /* saw no "$@", or not only "$@" but some * real text is there too */ /* insert "empty variable" reference, this makes * e.g. "", $empty"" etc to not disappear */ o_addchr(word, SPECIAL_VAR_SYMBOL); o_addchr(word, SPECIAL_VAR_SYMBOL); } } command->argv = add_string_to_strings(command->argv, xstrdup(word->data)); debug_print_strings("word appended to argv", command->argv); } o_reset(word); ctx->pending_redirect = NULL; #if ENABLE_HUSH_LOOPS /* Force FOR to have just one word (variable name) */ /* NB: basically, this makes hush see "for v in ..." syntax as if * as it is "for v; in ...". FOR and IN become two pipe structs * in parse tree. */ if (ctx->ctx_res_w == RES_FOR) { //TODO: check that command->argv[0] is a valid variable name! done_pipe(ctx, PIPE_SEQ); } #endif #if ENABLE_HUSH_CASE /* Force CASE to have just one word */ if (ctx->ctx_res_w == RES_CASE) { done_pipe(ctx, PIPE_SEQ); } #endif debug_printf_parse("done_word return 0\n"); return 0; } /* If a redirect is immediately preceded by a number, that number is * supposed to tell which file descriptor to redirect. This routine * looks for such preceding numbers. In an ideal world this routine * needs to handle all the following classes of redirects... * echo 2>foo # redirects fd 2 to file "foo", nothing passed to echo * echo 49>foo # redirects fd 49 to file "foo", nothing passed to echo * echo -2>foo # redirects fd 1 to file "foo", "-2" passed to echo * echo 49x>foo # redirects fd 1 to file "foo", "49x" passed to echo * A -1 output from this program means no valid number was found, so the * caller should use the appropriate default for this redirection. */ static int redirect_opt_num(o_string *o) { int num; if (o->length == 0) return -1; for (num = 0; num < o->length; num++) { if (!isdigit(o->data[num])) { return -1; } } num = atoi(o->data); o_reset(o); return num; } #if BB_MMU #define parse_stream(pstring, input, end_trigger) \ parse_stream(input, end_trigger) #endif static struct pipe *parse_stream(char **pstring, struct in_str *input, int end_trigger); static void parse_and_run_string(const char *s); #if ENABLE_HUSH_TICK static FILE *generate_stream_from_string(const char *s) { FILE *pf; int pid, channel[2]; xpipe(channel); pid = BB_MMU ? fork() : vfork(); if (pid < 0) bb_perror_msg_and_die(BB_MMU ? "fork" : "vfork"); if (pid == 0) { /* child */ #if ENABLE_HUSH_JOB die_sleep = 0; /* do not restore tty pgrp on xfunc death */ #endif /* Process substitution is not considered to be usual * 'command execution'. * SUSv3 says ctrl-Z should be ignored, ctrl-C should not. */ bb_signals(0 + (1 << SIGTSTP) + (1 << SIGTTIN) + (1 << SIGTTOU) , SIG_IGN); close(channel[0]); /* NB: close _first_, then move fd! */ xmove_fd(channel[1], 1); /* Prevent it from trying to handle ctrl-z etc */ USE_HUSH_JOB(G.run_list_level = 1;) #if BB_MMU reset_traps_to_defaults(); parse_and_run_string(s); _exit(G.last_return_code); #else /* We re-execute after vfork on NOMMU. This makes this script safe: * yes "0123456789012345678901234567890" | dd bs=32 count=64k >BIG * huge=`cat BIG` # was blocking here forever * echo OK */ re_execute_shell(s); #endif } /* parent */ #if ENABLE_HUSH_JOB die_sleep = -1; /* restore tty pgrp on xfunc death */ #endif clean_up_after_re_execute(); close(channel[1]); pf = fdopen(channel[0], "r"); return pf; } /* Return code is exit status of the process that is run. */ static int process_command_subs(o_string *dest, const char *s) { FILE *pf; struct in_str pipe_str; int ch, eol_cnt; pf = generate_stream_from_string(s); if (pf == NULL) return 1; close_on_exec_on(fileno(pf)); /* Now send results of command back into original context */ setup_file_in_str(&pipe_str, pf); eol_cnt = 0; while ((ch = i_getch(&pipe_str)) != EOF) { if (ch == '\n') { eol_cnt++; continue; } while (eol_cnt) { o_addchr(dest, '\n'); eol_cnt--; } o_addQchr(dest, ch); } debug_printf("done reading from pipe, pclose()ing\n"); /* Note: we got EOF, and we just close the read end of the pipe. * We do not wait for the `cmd` child to terminate. bash and ash do. * Try these: * echo `echo Hi; exec 1>&-; sleep 2` - bash waits 2 sec * `false`; echo $? - bash outputs "1" */ fclose(pf); debug_printf("closed FILE from child. return 0\n"); return 0; } #endif static int parse_group(o_string *dest, struct parse_context *ctx, struct in_str *input, int ch) { /* dest contains characters seen prior to ( or {. * Typically it's empty, but for function defs, * it contains function name (without '()'). */ struct pipe *pipe_list; int endch; struct command *command = ctx->command; debug_printf_parse("parse_group entered\n"); #if ENABLE_HUSH_FUNCTIONS if (ch == 'F') { /* function definition? */ bb_error_msg("aha '%s' is a function, parsing it...", dest->data); //command->fname = dest->data; command->grp_type = GRP_FUNCTION; //TODO: review every o_reset() location... do they handle all o_string fields correctly? memset(dest, 0, sizeof(*dest)); } #endif if (command->argv /* word [word](... */ || dest->length /* word(... */ || dest->nonnull /* ""(... */ ) { syntax(NULL); debug_printf_parse("parse_group return 1: " "syntax error, groups and arglists don't mix\n"); return 1; } endch = '}'; if (ch == '(') { endch = ')'; command->grp_type = GRP_SUBSHELL; } { #if !BB_MMU char *as_string = NULL; #endif pipe_list = parse_stream(&as_string, input, endch); #if !BB_MMU if (as_string) o_addstr(&ctx->as_string, as_string); #endif /* empty ()/{} or parse error? */ if (!pipe_list || pipe_list == ERR_PTR) { #if !BB_MMU free(as_string); #endif syntax(NULL); debug_printf_parse("parse_group return 1: " "parse_stream returned %p\n", pipe_list); return 1; } command->group = pipe_list; #if !BB_MMU as_string[strlen(as_string) - 1] = '\0'; /* plink ')' or '}' */ command->group_as_string = as_string; debug_printf_parse("end of group, remembering as:'%s'\n", command->group_as_string); #endif } debug_printf_parse("parse_group return 0\n"); return 0; /* command remains "open", available for possible redirects */ } #if ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT /* Subroutines for copying $(...) and `...` things */ static void add_till_backquote(o_string *dest, struct in_str *input); /* '...' */ static void add_till_single_quote(o_string *dest, struct in_str *input) { while (1) { int ch = i_getch(input); if (ch == EOF) break; if (ch == '\'') break; o_addchr(dest, ch); } } /* "...\"...`..`...." - do we need to handle "...$(..)..." too? */ static void add_till_double_quote(o_string *dest, struct in_str *input) { while (1) { int ch = i_getch(input); if (ch == '"') break; if (ch == '\\') { /* \x. Copy both chars. */ o_addchr(dest, ch); ch = i_getch(input); } if (ch == EOF) break; o_addchr(dest, ch); if (ch == '`') { add_till_backquote(dest, input); o_addchr(dest, ch); continue; } //if (ch == '$') ... } } /* Process `cmd` - copy contents until "`" is seen. Complicated by * \` quoting. * "Within the backquoted style of command substitution, backslash * shall retain its literal meaning, except when followed by: '$', '`', or '\'. * The search for the matching backquote shall be satisfied by the first * backquote found without a preceding backslash; during this search, * if a non-escaped backquote is encountered within a shell comment, * a here-document, an embedded command substitution of the $(command) * form, or a quoted string, undefined results occur. A single-quoted * or double-quoted string that begins, but does not end, within the * "`...`" sequence produces undefined results." * Example Output * echo `echo '\'TEST\`echo ZZ\`BEST` \TESTZZBEST */ static void add_till_backquote(o_string *dest, struct in_str *input) { while (1) { int ch = i_getch(input); if (ch == '`') break; if (ch == '\\') { /* \x. Copy both chars unless it is \` */ int ch2 = i_getch(input); if (ch2 != '`' && ch2 != '$' && ch2 != '\\') o_addchr(dest, ch); ch = ch2; } if (ch == EOF) break; o_addchr(dest, ch); } } /* Process $(cmd) - copy contents until ")" is seen. Complicated by * quoting and nested ()s. * "With the $(command) style of command substitution, all characters * following the open parenthesis to the matching closing parenthesis * constitute the command. Any valid shell script can be used for command, * except a script consisting solely of redirections which produces * unspecified results." * Example Output * echo $(echo '(TEST)' BEST) (TEST) BEST * echo $(echo 'TEST)' BEST) TEST) BEST * echo $(echo \(\(TEST\) BEST) ((TEST) BEST */ static void add_till_closing_paren(o_string *dest, struct in_str *input, bool dbl) { int count = 0; while (1) { int ch = i_getch(input); if (ch == EOF) break; if (ch == '(') count++; if (ch == ')') { if (--count < 0) { if (!dbl) break; if (i_peek(input) == ')') { i_getch(input); break; } } } o_addchr(dest, ch); if (ch == '\'') { add_till_single_quote(dest, input); o_addchr(dest, ch); continue; } if (ch == '"') { add_till_double_quote(dest, input); o_addchr(dest, ch); continue; } if (ch == '\\') { /* \x. Copy verbatim. Important for \(, \) */ ch = i_getch(input); if (ch == EOF) break; o_addchr(dest, ch); continue; } } } #endif /* ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT */ /* Return code: 0 for OK, 1 for syntax error */ #if BB_MMU #define handle_dollar(as_string, dest, input) \ handle_dollar(dest, input) #endif static int handle_dollar(o_string *as_string, o_string *dest, struct in_str *input) { int expansion; int ch = i_peek(input); /* first character after the $ */ unsigned char quote_mask = dest->o_escape ? 0x80 : 0; debug_printf_parse("handle_dollar entered: ch='%c'\n", ch); if (isalpha(ch)) { ch = i_getch(input); #if !BB_MMU if (as_string) o_addchr(as_string, ch); #endif make_var: o_addchr(dest, SPECIAL_VAR_SYMBOL); while (1) { debug_printf_parse(": '%c'\n", ch); o_addchr(dest, ch | quote_mask); quote_mask = 0; ch = i_peek(input); if (!isalnum(ch) && ch != '_') break; ch = i_getch(input); #if !BB_MMU if (as_string) o_addchr(as_string, ch); #endif } o_addchr(dest, SPECIAL_VAR_SYMBOL); } else if (isdigit(ch)) { make_one_char_var: ch = i_getch(input); #if !BB_MMU if (as_string) o_addchr(as_string, ch); #endif o_addchr(dest, SPECIAL_VAR_SYMBOL); debug_printf_parse(": '%c'\n", ch); o_addchr(dest, ch | quote_mask); o_addchr(dest, SPECIAL_VAR_SYMBOL); } else switch (ch) { case '$': /* pid */ case '!': /* last bg pid */ case '?': /* last exit code */ case '#': /* number of args */ case '*': /* args */ case '@': /* args */ goto make_one_char_var; case '{': { bool first_char, all_digits; o_addchr(dest, SPECIAL_VAR_SYMBOL); ch = i_getch(input); #if !BB_MMU if (as_string) o_addchr(as_string, ch); #endif /* XXX maybe someone will try to escape the '}' */ expansion = 0; first_char = true; all_digits = false; while (1) { ch = i_getch(input); #if !BB_MMU if (as_string) o_addchr(as_string, ch); #endif if (ch == '}') break; if (first_char) { if (ch == '#') /* ${#var}: length of var contents */ goto char_ok; else if (isdigit(ch)) { all_digits = true; goto char_ok; } } if (expansion < 2 && ( (all_digits && !isdigit(ch)) || (!all_digits && !isalnum(ch) && ch != '_') ) ) { /* handle parameter expansions * http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_06_02 */ if (first_char) goto case_default; switch (ch) { case ':': /* null modifier */ if (expansion == 0) { debug_printf_parse(": null modifier\n"); ++expansion; break; } goto case_default; #if 0 /* not implemented yet :( */ case '#': /* remove prefix */ case '%': /* remove suffix */ if (expansion == 0) { debug_printf_parse(": remove suffix/prefix\n"); expansion = 2; break; } goto case_default; #endif case '-': /* default value */ case '=': /* assign default */ case '+': /* alternative */ case '?': /* error indicate */ debug_printf_parse(": parameter expansion\n"); expansion = 2; break; default: case_default: syntax("unterminated ${name}"); debug_printf_parse("handle_dollar return 1: unterminated ${name}\n"); return 1; } } char_ok: debug_printf_parse(": '%c'\n", ch); o_addchr(dest, ch | quote_mask); quote_mask = 0; first_char = false; } o_addchr(dest, SPECIAL_VAR_SYMBOL); break; } #if (ENABLE_SH_MATH_SUPPORT || ENABLE_HUSH_TICK) case '(': { # if !BB_MMU int pos; # endif ch = i_getch(input); # if !BB_MMU if (as_string) o_addchr(as_string, ch); # endif # if ENABLE_SH_MATH_SUPPORT if (i_peek(input) == '(') { ch = i_getch(input); # if !BB_MMU if (as_string) o_addchr(as_string, ch); # endif o_addchr(dest, SPECIAL_VAR_SYMBOL); o_addchr(dest, /*quote_mask |*/ '+'); # if !BB_MMU pos = dest->length; # endif add_till_closing_paren(dest, input, true); # if !BB_MMU if (as_string) { o_addstr(as_string, dest->data + pos); o_addchr(as_string, ')'); o_addchr(as_string, ')'); } # endif o_addchr(dest, SPECIAL_VAR_SYMBOL); break; } # endif # if ENABLE_HUSH_TICK //int pos = dest->length; o_addchr(dest, SPECIAL_VAR_SYMBOL); o_addchr(dest, quote_mask | '`'); # if !BB_MMU pos = dest->length; # endif add_till_closing_paren(dest, input, false); # if !BB_MMU if (as_string) { o_addstr(as_string, dest->data + pos); o_addchr(as_string, '`'); } # endif //debug_printf_subst("SUBST RES2 '%s'\n", dest->data + pos); o_addchr(dest, SPECIAL_VAR_SYMBOL); # endif break; } #endif case '_': ch = i_getch(input); #if !BB_MMU if (as_string) o_addchr(as_string, ch); #endif ch = i_peek(input); if (isalnum(ch)) { /* it's $_name or $_123 */ ch = '_'; goto make_var; } /* else: it's $_ */ /* TODO: */ /* $_ Shell or shell script name; or last cmd name */ /* $- Option flags set by set builtin or shell options (-i etc) */ default: o_addQchr(dest, '$'); } debug_printf_parse("handle_dollar return 0\n"); return 0; } #if BB_MMU #define parse_stream_dquoted(as_string, dest, input, dquote_end) \ parse_stream_dquoted(dest, input, dquote_end) #endif static int parse_stream_dquoted(o_string *as_string, o_string *dest, struct in_str *input, int dquote_end) { int ch; int next; again: ch = i_getch(input); #if !BB_MMU if (as_string && ch != EOF) o_addchr(as_string, ch); #endif if (ch == dquote_end) { /* may be only '"' or EOF */ dest->nonnull = 1; if (dest->o_assignment == NOT_ASSIGNMENT) dest->o_escape ^= 1; debug_printf_parse("parse_stream_dquoted return 0\n"); return 0; } if (ch == EOF) { syntax("unterminated \""); debug_printf_parse("parse_stream_dquoted return 1: unterminated \"\n"); return 1; } next = '\0'; if (ch != '\n') { next = i_peek(input); } debug_printf_parse(": ch=%c (%d) escape=%d\n", ch, ch, dest->o_escape); if (ch == '\\') { if (next == EOF) { syntax("\\"); debug_printf_parse("parse_stream_dquoted return 1: \\\n"); return 1; } /* bash: * "The backslash retains its special meaning [in "..."] * only when followed by one of the following characters: * $, `, ", \, or . A double quote may be quoted * within double quotes by preceding it with a backslash. * If enabled, history expansion will be performed unless * an ! appearing in double quotes is escaped using * a backslash. The backslash preceding the ! is not removed." */ if (strchr("$`\"\\", next) != NULL) { o_addqchr(dest, i_getch(input)); } else { o_addqchr(dest, '\\'); } goto again; } if (ch == '$') { if (handle_dollar(as_string, dest, input) != 0) { debug_printf_parse("parse_stream_dquoted return 1: " "handle_dollar returned non-0\n"); return 1; } goto again; } #if ENABLE_HUSH_TICK if (ch == '`') { //int pos = dest->length; o_addchr(dest, SPECIAL_VAR_SYMBOL); o_addchr(dest, 0x80 | '`'); add_till_backquote(dest, input); o_addchr(dest, SPECIAL_VAR_SYMBOL); //debug_printf_subst("SUBST RES3 '%s'\n", dest->data + pos); goto again; } #endif o_addQchr(dest, ch); if (ch == '=' && (dest->o_assignment == MAYBE_ASSIGNMENT || dest->o_assignment == WORD_IS_KEYWORD) && is_assignment(dest->data) ) { dest->o_assignment = DEFINITELY_ASSIGNMENT; } goto again; } /* * Scan input until EOF or end_trigger char. * Return a list of pipes to execute, or NULL on EOF * or if end_trigger character is met. * On syntax error, exit is shell is not interactive, * reset parsing machinery and start parsing anew, * or return ERR_PTR. */ static struct pipe *parse_stream(char **pstring, struct in_str *input, int end_trigger) { struct parse_context ctx; o_string dest = NULL_O_STRING; int is_in_dquote; /* Double-quote state is handled in the state variable is_in_dquote. * A single-quote triggers a bypass of the main loop until its mate is * found. When recursing, quote state is passed in via dest->o_escape. */ debug_printf_parse("parse_stream entered, end_trigger='%c'\n", end_trigger ? : 'X'); G.ifs = get_local_var_value("IFS"); if (G.ifs == NULL) G.ifs = " \t\n"; reset: #if ENABLE_HUSH_INTERACTIVE input->promptmode = 0; /* PS1 */ #endif /* dest.o_assignment = MAYBE_ASSIGNMENT; - already is */ initialize_context(&ctx); is_in_dquote = 0; while (1) { const char *is_ifs; const char *is_special; int ch; int next; int redir_fd; redir_type redir_style; if (is_in_dquote) { if (parse_stream_dquoted(&ctx.as_string, &dest, input, '"')) { goto parse_error; } /* We reached closing '"' */ is_in_dquote = 0; } ch = i_getch(input); debug_printf_parse(": ch=%c (%d) escape=%d\n", ch, ch, dest.o_escape); if (ch == EOF) { struct pipe *pi; if (done_word(&dest, &ctx)) { goto parse_error; } o_free(&dest); done_pipe(&ctx, PIPE_SEQ); pi = ctx.list_head; /* If we got nothing... */ // TODO: test script consisting of just "&" if (pi->num_cmds == 0 IF_HAS_KEYWORDS( && pi->res_word == RES_NONE) ) { free_pipe_list(pi, 0); pi = NULL; } debug_printf_parse("parse_stream return %p\n", pi); #if !BB_MMU debug_printf_parse("as_string '%s'\n", ctx.as_string.data); if (pstring) *pstring = ctx.as_string.data; else o_free_unsafe(&ctx.as_string); #endif return pi; } #if !BB_MMU o_addchr(&ctx.as_string, ch); #endif is_ifs = strchr(G.ifs, ch); is_special = strchr("<>;&|(){}#'" /* special outside of "str" */ "\\$\"" USE_HUSH_TICK("`") /* always special */ , ch); if (!is_special && !is_ifs) { /* ordinary char */ o_addQchr(&dest, ch); if ((dest.o_assignment == MAYBE_ASSIGNMENT || dest.o_assignment == WORD_IS_KEYWORD) && ch == '=' && is_assignment(dest.data) ) { dest.o_assignment = DEFINITELY_ASSIGNMENT; } continue; } if (is_ifs) { if (done_word(&dest, &ctx)) { goto parse_error; } if (ch == '\n') { #if ENABLE_HUSH_CASE /* "case ... in word) ..." - * newlines are ignored (but ';' wouldn't be) */ if (ctx.command->argv == NULL && ctx.ctx_res_w == RES_MATCH ) { continue; } #endif /* Treat newline as a command separator. */ done_pipe(&ctx, PIPE_SEQ); dest.o_assignment = MAYBE_ASSIGNMENT; ch = ';'; /* note: if (is_ifs) continue; * will still trigger for us */ } } if (end_trigger && end_trigger == ch) { //TODO: disallow "{ cmd }" without semicolon if (done_word(&dest, &ctx)) { goto parse_error; } done_pipe(&ctx, PIPE_SEQ); dest.o_assignment = MAYBE_ASSIGNMENT; /* Do we sit outside of any if's, loops or case's? */ if (!HAS_KEYWORDS IF_HAS_KEYWORDS(|| (ctx.ctx_res_w == RES_NONE && ctx.old_flag == 0)) ) { debug_printf_parse("parse_stream return %p: " "end_trigger char found\n", ctx.list_head); o_free(&dest); #if !BB_MMU debug_printf_parse("as_string '%s'\n", ctx.as_string.data); if (pstring) *pstring = ctx.as_string.data; else o_free_unsafe(&ctx.as_string); #endif return ctx.list_head; } } if (is_ifs) continue; if (dest.o_assignment == MAYBE_ASSIGNMENT) { /* ch is a special char and thus this word * cannot be an assignment */ dest.o_assignment = NOT_ASSIGNMENT; } next = '\0'; if (ch != '\n') { next = i_peek(input); } switch (ch) { case '#': if (dest.length == 0) { while (1) { ch = i_peek(input); if (ch == EOF || ch == '\n') break; i_getch(input); /* note: we do not add it to &ctx.as_string */ } #if !BB_MMU //TODO: go back one char? o_addchr(&ctx.as_string, '\n'); #endif } else { o_addQchr(&dest, ch); } break; case '\\': if (next == EOF) { syntax("\\"); goto parse_error; } o_addchr(&dest, '\\'); ch = i_getch(input); o_addchr(&dest, ch); #if !BB_MMU o_addchr(&ctx.as_string, ch); #endif break; case '$': if (handle_dollar(&ctx.as_string, &dest, input) != 0) { debug_printf_parse("parse_stream parse error: " "handle_dollar returned non-0\n"); goto parse_error; } break; case '\'': dest.nonnull = 1; while (1) { ch = i_getch(input); if (ch == EOF) { syntax("unterminated '"); goto parse_error; } #if !BB_MMU o_addchr(&ctx.as_string, ch); #endif if (ch == '\'') break; if (dest.o_assignment == NOT_ASSIGNMENT) o_addqchr(&dest, ch); else o_addchr(&dest, ch); } break; case '"': dest.nonnull = 1; is_in_dquote ^= 1; /* invert */ if (dest.o_assignment == NOT_ASSIGNMENT) dest.o_escape ^= 1; break; #if ENABLE_HUSH_TICK case '`': { //int pos = dest.length; o_addchr(&dest, SPECIAL_VAR_SYMBOL); o_addchr(&dest, '`'); add_till_backquote(&dest, input); o_addchr(&dest, SPECIAL_VAR_SYMBOL); //debug_printf_subst("SUBST RES3 '%s'\n", dest.data + pos); break; } #endif case '>': redir_fd = redirect_opt_num(&dest); if (done_word(&dest, &ctx)) { goto parse_error; } redir_style = REDIRECT_OVERWRITE; if (next == '>') { redir_style = REDIRECT_APPEND; ch = i_getch(input); #if !BB_MMU o_addchr(&ctx.as_string, ch); #endif } #if 0 else if (next == '(') { syntax(">(process) not supported"); goto parse_error; } #endif setup_redirect(&ctx, redir_fd, redir_style, input); break; case '<': redir_fd = redirect_opt_num(&dest); if (done_word(&dest, &ctx)) { goto parse_error; } redir_style = REDIRECT_INPUT; if (next == '<') { redir_style = REDIRECT_HEREIS; ch = i_getch(input); #if !BB_MMU o_addchr(&ctx.as_string, ch); #endif } else if (next == '>') { redir_style = REDIRECT_IO; ch = i_getch(input); #if !BB_MMU o_addchr(&ctx.as_string, ch); #endif } #if 0 else if (next == '(') { syntax("<(process) not supported"); goto parse_error; } #endif setup_redirect(&ctx, redir_fd, redir_style, input); break; case ';': #if ENABLE_HUSH_CASE case_semi: #endif if (done_word(&dest, &ctx)) { goto parse_error; } done_pipe(&ctx, PIPE_SEQ); #if ENABLE_HUSH_CASE /* Eat multiple semicolons, detect * whether it means something special */ while (1) { ch = i_peek(input); if (ch != ';') break; ch = i_getch(input); #if !BB_MMU o_addchr(&ctx.as_string, ch); #endif if (ctx.ctx_res_w == RES_CASEI) { ctx.ctx_dsemicolon = 1; ctx.ctx_res_w = RES_MATCH; break; } } #endif new_cmd: /* We just finished a cmd. New one may start * with an assignment */ dest.o_assignment = MAYBE_ASSIGNMENT; break; case '&': if (done_word(&dest, &ctx)) { goto parse_error; } if (next == '&') { ch = i_getch(input); #if !BB_MMU o_addchr(&ctx.as_string, ch); #endif done_pipe(&ctx, PIPE_AND); } else { done_pipe(&ctx, PIPE_BG); } goto new_cmd; case '|': if (done_word(&dest, &ctx)) { goto parse_error; } #if ENABLE_HUSH_CASE if (ctx.ctx_res_w == RES_MATCH) break; /* we are in case's "word | word)" */ #endif if (next == '|') { /* || */ ch = i_getch(input); #if !BB_MMU o_addchr(&ctx.as_string, ch); #endif done_pipe(&ctx, PIPE_OR); } else { /* we could pick up a file descriptor choice here * with redirect_opt_num(), but bash doesn't do it. * "echo foo 2| cat" yields "foo 2". */ done_command(&ctx); } goto new_cmd; case '(': #if ENABLE_HUSH_CASE /* "case... in [(]word)..." - skip '(' */ if (ctx.ctx_res_w == RES_MATCH && ctx.command->argv == NULL /* not (word|(... */ && dest.length == 0 /* not word(... */ && dest.nonnull == 0 /* not ""(... */ ) { continue; } #endif #if ENABLE_HUSH_FUNCTIONS if (dest.length != 0 /* not just () but word() */ && dest.nonnull == 0 /* not a"b"c() */ && ctx.command->argv == NULL /* it's the first word */ //TODO: "func ( ) {...}" - note spaces - is valid format too in bash && i_peek(input) == ')' && !match_reserved_word(&dest) ) { bb_error_msg("seems like a function definition"); i_getch(input); //if !BB_MMU o_addchr(&ctx.as_string... do { //TODO: do it properly. ch = i_getch(input); } while (ch == ' ' || ch == '\n'); if (ch != '{') { syntax("was expecting {"); goto parse_error; } ch = 'F'; /* magic value */ } #endif case '{': if (parse_group(&dest, &ctx, input, ch) != 0) { goto parse_error; } goto new_cmd; case ')': #if ENABLE_HUSH_CASE if (ctx.ctx_res_w == RES_MATCH) goto case_semi; #endif case '}': /* proper use of this character is caught by end_trigger: * if we see {, we call parse_group(..., end_trigger='}') * and it will match } earlier (not here). */ syntax("unexpected } or )"); goto parse_error; default: if (HUSH_DEBUG) bb_error_msg_and_die("BUG: unexpected %c\n", ch); } } /* while (1) */ parse_error: { struct parse_context *pctx; IF_HAS_KEYWORDS(struct parse_context *p2;) /* Clean up allocated tree. * Samples for finding leaks on syntax error recovery path. * Run them from interactive shell, watch pmap `pidof hush`. * while if false; then false; fi do break; done * (bash accepts it) * while if false; then false; fi; do break; fi * Samples to catch leaks at execution: * while if (true | {true;}); then echo ok; fi; do break; done * while if (true | {true;}); then echo ok; fi; do (if echo ok; break; then :; fi) | cat; break; done */ pctx = &ctx; do { /* Update pipe/command counts, * otherwise freeing may miss some */ done_pipe(pctx, PIPE_SEQ); debug_printf_clean("freeing list %p from ctx %p\n", pctx->list_head, pctx); debug_print_tree(pctx->list_head, 0); free_pipe_list(pctx->list_head, 0); debug_printf_clean("freed list %p\n", pctx->list_head); #if !BB_MMU o_free_unsafe(&pctx->as_string); #endif IF_HAS_KEYWORDS(p2 = pctx->stack;) if (pctx != &ctx) { free(pctx); } IF_HAS_KEYWORDS(pctx = p2;) } while (HAS_KEYWORDS && pctx); /* Free text, clear all dest fields */ o_free(&dest); /* If we are not in top-level parse, we return, * our caller will propagate error. */ if (end_trigger != ';') { #if !BB_MMU if (pstring) *pstring = NULL; #endif return ERR_PTR; } /* Discard cached input, force prompt */ input->p = NULL; USE_HUSH_INTERACTIVE(input->promptme = 1;) goto reset; } } /* Executing from string: eval, sh -c '...' * or from file: /etc/profile, . file, sh