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Diffstat (limited to 'hush.c')
| -rw-r--r-- | hush.c | 2191 |
1 files changed, 2191 insertions, 0 deletions
@@ -0,0 +1,2191 @@ +/* vi: set sw=4 ts=4: */ +/* + * sh.c -- 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 <larry@doolittle.boa.org> + * + * 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) 2000 by Lineo, Inc., and + * written by Erik Andersen <andersen@lineo.com>, <andersee@debian.org>. + * 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: + * simple_itoa() was lifted from boa-0.93.15 + * b_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. + * + * Bash grammar not implemented: (how many of these were in original sh?) + * $@ (those sure look like weird quoting rules) + * $_ + * ! negation operator for pipes + * &> and >& redirection of stdout+stderr + * Brace Expansion + * Tilde Expansion + * fancy forms of Parameter Expansion + * Arithmetic Expansion + * <(list) and >(list) Process Substitution + * reserved words: if, then, elif, else, fi, while, until, for, + * do, done, case + * Here Documents ( << word ) + * Functions + * Major bugs: + * job handling woefully incomplete and buggy + * reserved word execution woefully incomplete and buggy + * incomplete reserved word sequence doesn't request more lines of input + * to-do: + * port selected bugfixes from post-0.49 busybox lash + * finish implementing reserved words + * handle children going into background + * clean up recognition of null pipes + * have builtin_exec set flag to avoid restore_redirects + * figure out if "echo foo}" is fixable + * check setting of global_argc and global_argv + * control-C handling, probably with longjmp + * VAR=value prefix for simple commands + * follow IFS rules more precisely, including update semantics + * write builtin_eval, builtin_ulimit, builtin_umask + * figure out what to do with backslash-newline + * explain why we use signal instead of sigaction + * propagate syntax errors, die on resource errors? + * continuation lines, both explicit and implicit - done? + * memory leak finding and plugging - done? + * more testing, especially quoting rules and redirection + * maybe change map[] to use 2-bit entries + * (eventually) remove all the printf's + * more integration with BusyBox: prompts, cmdedit, applets + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ +#include <ctype.h> /* isalpha, isdigit */ +#include <unistd.h> /* getpid */ +#include <stdlib.h> /* getenv, atoi */ +#include <string.h> /* strchr */ +#include <stdio.h> /* popen etc. */ +#include <glob.h> /* glob, of course */ +#include <stdarg.h> /* va_list */ +#include <errno.h> +#include <fcntl.h> +#include <getopt.h> /* should be pretty obvious */ + +#include <sys/types.h> +#include <sys/wait.h> +#include <signal.h> + +/* #include <dmalloc.h> */ +/* #define DEBUG_SHELL */ + +#ifdef BB_VER +#include "busybox.h" +#include "cmdedit.h" +#else +/* in place of #include "busybox.h"; much of this is indeed + * pasted in from the copy of busybox.h in busybox-0.49pre */ + +#define xrealloc realloc +#define applet_name "hush" +#define shell_main main + +extern void *xmalloc(size_t size) +{ + void *ptr = malloc(size); + + if (!ptr) { + fprintf(stderr, "memory_exhausted\n"); + exit (EXIT_FAILURE); + } + return ptr; +} + +extern void usage(const char *usage) +{ + fprintf(stderr, "Usage: %s\n", usage); + exit(EXIT_FAILURE); +} + +static void verror_msg(const char *s, va_list p) +{ + fflush(stdout); + fprintf(stderr, "%s: ", applet_name); + vfprintf(stderr, s, p); + fflush(stderr); +} + +extern void error_msg(const char *s, ...) +{ + va_list p; + + va_start(p, s); + verror_msg(s, p); + va_end(p); +} + +extern void error_msg_and_die(const char *s, ...) +{ + va_list p; + + va_start(p, s); + verror_msg(s, p); + va_end(p); + exit(EXIT_FAILURE); +} + +static void vperror_msg(const char *s, va_list p) +{ + fflush(stdout); + fprintf(stderr, "%s: ", applet_name); + if (s && *s) { + vfprintf(stderr, s, p); + fputs(": ", stderr); + } + fprintf(stderr, "%s\n", strerror(errno)); + fflush(stderr); +} + +extern void perror_msg(const char *s, ...) +{ + va_list p; + + va_start(p, s); + vperror_msg(s, p); + va_end(p); +} + +extern void perror_msg_and_die(const char *s, ...) +{ + va_list p; + + va_start(p, s); + vperror_msg(s, p); + va_end(p); + exit(EXIT_FAILURE); +} + +FILE *xfopen(const char *path, const char *mode) +{ + FILE *fp; + if ((fp = fopen(path, mode)) == NULL) + perror_msg_and_die(path); + return fp; +} +#endif /* of busybox.h replacement */ + +typedef enum { + 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 */ +struct {int mode; int default_fd; char *descrip;} 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_SEQ = 1, + PIPE_AND = 2, + PIPE_OR = 3, + PIPE_BG = 4, +} pipe_style; + +/* might eventually control execution */ +typedef enum { + RES_NONE = 0, + RES_IF = 1, + RES_THEN = 2, + RES_ELIF = 3, + RES_ELSE = 4, + RES_FI = 5, + RES_FOR = 6, + RES_WHILE = 7, + RES_UNTIL = 8, + RES_DO = 9, + RES_DONE = 10, + RES_XXXX = 11 +} reserved_style; +#define FLAG_END (1<<RES_NONE) +#define FLAG_IF (1<<RES_IF) +#define FLAG_THEN (1<<RES_THEN) +#define FLAG_ELIF (1<<RES_ELIF) +#define FLAG_ELSE (1<<RES_ELSE) +#define FLAG_FI (1<<RES_FI) +#define FLAG_FOR (1<<RES_FOR) +#define FLAG_WHILE (1<<RES_WHILE) +#define FLAG_UNTIL (1<<RES_UNTIL) +#define FLAG_DO (1<<RES_DO) +#define FLAG_DONE (1<<RES_DONE) +#define FLAG_START (1<<RES_XXXX) + +/* This holds pointers to the various results of parsing */ +struct p_context { + struct child_prog *child; + struct pipe *list_head; + struct pipe *pipe; + struct redir_struct *pending_redirect; + reserved_style w; + int old_flag; /* for figuring out valid reserved words */ + struct p_context *stack; + /* How about quoting status? */ +}; + +struct redir_struct { + redir_type type; /* type of redirection */ + int fd; /* file descriptor being redirected */ + int dup; /* -1, or file descriptor being duplicated */ + struct redir_struct *next; /* pointer to the next redirect in the list */ + glob_t word; /* *word.gl_pathv is the filename */ +}; + +struct child_prog { + pid_t pid; /* 0 if exited */ + char **argv; /* program name and arguments */ + struct pipe *group; /* if non-NULL, first in group or subshell */ + int subshell; /* flag, non-zero if group must be forked */ + struct redir_struct *redirects; /* I/O redirections */ + glob_t glob_result; /* result of parameter globbing */ + int is_stopped; /* is the program currently running? */ + struct pipe *family; /* pointer back to the child's parent pipe */ +}; + +struct pipe { + int jobid; /* job number */ + int num_progs; /* total number of programs in job */ + int running_progs; /* number of programs running */ + char *text; /* name of job */ + char *cmdbuf; /* buffer various argv's point into */ + pid_t pgrp; /* process group ID for the job */ + struct child_prog *progs; /* array of commands in pipe */ + struct pipe *next; /* to track background commands */ + int stopped_progs; /* number of programs alive, but stopped */ + int job_context; /* bitmask defining current context */ + pipe_style followup; /* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */ + reserved_style r_mode; /* supports if, for, while, until */ + struct jobset *job_list; +}; + +struct jobset { + struct pipe *head; /* head of list of running jobs */ + struct pipe *fg; /* current foreground job */ +}; + +struct close_me { + int fd; + struct close_me *next; +}; + +/* globals, connect us to the outside world + * the first three support $?, $#, and $1 */ +char **global_argv; +unsigned int global_argc; +unsigned int last_return_code; +extern char **environ; /* This is in <unistd.h>, but protected with __USE_GNU */ + +/* Variables we export */ +unsigned int shell_context; /* Used in cmdedit.c to reset the + * context when someone hits ^C */ + +/* "globals" within this file */ +static char *ifs=NULL; +static char map[256]; +static int fake_mode=0; +static int interactive=0; +static struct close_me *close_me_head = NULL; +static char *cwd; +static struct jobset job_list = { NULL, NULL }; +static unsigned int last_bg_pid=0; +static char *PS1; +static char *PS2 = "> "; + +#define B_CHUNK (100) +#define B_NOSPAC 1 +#define MAX_LINE 256 /* for cwd */ +#define MAX_READ 256 /* for builtin_read */ + +typedef struct { + char *data; + int length; + int maxlen; + int quote; + int nonnull; +} o_string; +#define NULL_O_STRING {NULL,0,0,0,0} +/* used for initialization: + o_string foo = NULL_O_STRING; */ + +/* I can almost use ordinary FILE *. Is open_memstream() universally + * available? Where is it documented? */ +struct in_str { + const char *p; + int __promptme; + int promptmode; + FILE *file; + int (*get) (struct in_str *); + int (*peek) (struct in_str *); +}; +#define b_getch(input) ((input)->get(input)) +#define b_peek(input) ((input)->peek(input)) + +#define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n" + +struct built_in_command { + char *cmd; /* name */ + char *descr; /* description */ + int (*function) (struct child_prog *); /* function ptr */ +}; + +/* belongs in busybox.h */ +static inline int max(int a, int b) { + return (a>b)?a:b; +} + +/* This should be in utility.c */ +#ifdef DEBUG_SHELL +static void debug_printf(const char *format, ...) +{ + va_list args; + va_start(args, format); + vfprintf(stderr, format, args); + va_end(args); +} +#else +static void debug_printf(const char *format, ...) { } +#endif +#define final_printf debug_printf + +void __syntax(char *file, int line) { + fprintf(stderr,"syntax error %s:%d\n",file,line); +} +#define syntax() __syntax(__FILE__, __LINE__) + +/* Index of subroutines: */ +/* function prototypes for builtins */ +static int builtin_cd(struct child_prog *child); +static int builtin_env(struct child_prog *child); +static int builtin_exec(struct child_prog *child); +static int builtin_exit(struct child_prog *child); +static int builtin_export(struct child_prog *child); +static int builtin_fg_bg(struct child_prog *child); +static int builtin_help(struct child_prog *child); +static int builtin_jobs(struct child_prog *child); +static int builtin_pwd(struct child_prog *child); +static int builtin_read(struct child_prog *child); +static int builtin_shift(struct child_prog *child); +static int builtin_source(struct child_prog *child); +static int builtin_ulimit(struct child_prog *child); +static int builtin_umask(struct child_prog *child); +static int builtin_unset(struct child_prog *child); +/* o_string manipulation: */ +static int b_check_space(o_string *o, int len); +static int b_addchr(o_string *o, int ch); +static void b_reset(o_string *o); +static int b_addqchr(o_string *o, int ch, int quote); +static int b_adduint(o_string *o, unsigned int i); +/* in_str manipulations: */ +static int static_get(struct in_str *i); +static int static_peek(struct in_str *i); +static int file_get(struct in_str *i); +static int file_peek(struct in_str *i); +static void setup_file_in_str(struct in_str *i, FILE *f); +static void setup_string_in_str(struct in_str *i, const char *s); +/* close_me manipulations: */ +static void mark_open(int fd); +static void mark_closed(int fd); +static void close_all(); +/* "run" the final data structures: */ +static char *indenter(int i); +static int run_list_test(struct pipe *head, int indent); +static int run_pipe_test(struct pipe *pi, int indent); +/* really run the final data structures: */ +static int setup_redirects(struct child_prog *prog, int squirrel[]); +static int pipe_wait(struct pipe *pi); +static int run_list_real(struct pipe *pi); +static void pseudo_exec(struct child_prog *child) __attribute__ ((noreturn)); +static int run_pipe_real(struct pipe *pi); +/* extended glob support: */ +static int globhack(const char *src, int flags, glob_t *pglob); +static int glob_needed(const char *s); +static int xglob(o_string *dest, int flags, glob_t *pglob); +/* data structure manipulation: */ +static int setup_redirect(struct p_context *ctx, int fd, redir_type style, struct in_str *input); +static void initialize_context(struct p_context *ctx); +static int done_word(o_string *dest, struct p_context *ctx); +static int done_command(struct p_context *ctx); +static int done_pipe(struct p_context *ctx, pipe_style type); +/* primary string parsing: */ +static int redirect_dup_num(struct in_str *input); +static int redirect_opt_num(o_string *o); +static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end); +static int parse_group(o_string *dest, struct p_context *ctx, struct in_str *input, int ch); +static void lookup_param(o_string *dest, struct p_context *ctx, o_string *src); +static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input); +static int parse_string(o_string *dest, struct p_context *ctx, const char *src); +static int parse_stream(o_string *dest, struct p_context *ctx, struct in_str *input0, int end_trigger); +/* setup: */ +static int parse_stream_outer(struct in_str *inp); +static int parse_string_outer(const char *s); +static int parse_file_outer(FILE *f); + +/* 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 can not. + * For example, 'unset foo | whatever' will parse and run, but foo will + * still be set at the end. */ +static struct built_in_command bltins[] = { + {"bg", "Resume a job in the background", builtin_fg_bg}, + {"cd", "Change working directory", builtin_cd}, + {"env", "Print all environment variables", builtin_env}, + {"exec", "Exec command, replacing this shell with the exec'd process", builtin_exec}, + {"exit", "Exit from shell()", builtin_exit}, + {"export", "Set environment variable", builtin_export}, + {"fg", "Bring job into the foreground", builtin_fg_bg}, + {"jobs", "Lists the active jobs", builtin_jobs}, + {"pwd", "Print current directory", builtin_pwd}, + {"read", "Input environment variable", builtin_read}, + {"shift", "Shift positional parameters", builtin_shift}, + {"ulimit","Controls resource limits", builtin_ulimit}, + {"umask","Sets file creation mask", builtin_umask}, + {"unset", "Unset environment variable", builtin_unset}, + {".", "Source-in and run commands in a file", builtin_source}, + {"help", "List shell built-in commands", builtin_help}, + {NULL, NULL, NULL} +}; + +/* built-in 'cd <path>' handler */ +static int builtin_cd(struct child_prog *child) +{ + char *newdir; + if (child->argv[1] == NULL) + newdir = getenv("HOME"); + else + newdir = child->argv[1]; + if (chdir(newdir)) { + printf("cd: %s: %s\n", newdir, strerror(errno)); + return EXIT_FAILURE; + } + getcwd(cwd, sizeof(char)*MAX_LINE); + return EXIT_SUCCESS; +} + +/* built-in 'env' handler */ +static int builtin_env(struct child_prog *dummy) +{ + char **e = environ; + if (e == NULL) return EXIT_FAILURE; + for (; *e; e++) { + puts(*e); + } + return EXIT_SUCCESS; +} + +/* built-in 'exec' handler */ +static int builtin_exec(struct child_prog *child) +{ + if (child->argv[1] == NULL) + return EXIT_SUCCESS; /* Really? */ + child->argv++; + pseudo_exec(child); + /* never returns */ +} + +/* built-in 'exit' handler */ +static int builtin_exit(struct child_prog *child) +{ + if (child->argv[1] == NULL) + exit(EXIT_SUCCESS); + exit (atoi(child->argv[1])); +} + +/* built-in 'export VAR=value' handler */ +static int builtin_export(struct child_prog *child) +{ + int res; + + if (child->argv[1] == NULL) { + return (builtin_env(child)); + } + res = putenv(child->argv[1]); + if (res) + fprintf(stderr, "export: %s\n", strerror(errno)); + return (res); +} + +/* built-in 'fg' and 'bg' handler */ +static int builtin_fg_bg(struct child_prog *child) +{ + int i, jobNum; + struct pipe *job=NULL; + + if (!child->argv[1] || child->argv[2]) { + error_msg("%s: exactly one argument is expected\n", + child->argv[0]); + return EXIT_FAILURE; + } + + if (sscanf(child->argv[1], "%%%d", &jobNum) != 1) { + error_msg("%s: bad argument '%s'\n", + child->argv[0], child->argv[1]); + return EXIT_FAILURE; + } + + for (job = child->family->job_list->head; job; job = job->next) { + if (job->jobid == jobNum) { + break; + } + } + + if (!job) { + error_msg("%s: unknown job %d\n", + child->argv[0], jobNum); + return EXIT_FAILURE; + } + + if (*child->argv[0] == 'f') { + /* Make this job the foreground job */ + /* suppress messages when run from /linuxrc mag@sysgo.de */ + if (tcsetpgrp(0, job->pgrp) && errno != ENOTTY) + perror_msg("tcsetpgrp"); + child->family->job_list->fg = job; + } + + /* Restart the processes in the job */ + for (i = 0; i < job->num_progs; i++) + job->progs[i].is_stopped = 0; + + kill(-job->pgrp, SIGCONT); + + job->stopped_progs = 0; + return EXIT_SUCCESS; +} + +/* built-in 'help' handler */ +static int builtin_help(struct child_prog *dummy) +{ + struct built_in_command *x; + + printf("\nBuilt-in commands:\n"); + printf("-------------------\n"); + for (x = bltins; x->cmd; x++) { + if (x->descr==NULL) + continue; + printf("%s\t%s\n", x->cmd, x->descr); + } + printf("\n\n"); + return EXIT_SUCCESS; +} + +/* built-in 'jobs' handler */ +static int builtin_jobs(struct child_prog *child) +{ + struct pipe *job; + char *status_string; + + for (job = child->family->job_list->head; job; job = job->next) { + if (job->running_progs == job->stopped_progs) + status_string = "Stopped"; + else + status_string = "Running"; + printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->text); + } + return EXIT_SUCCESS; +} + + +/* built-in 'pwd' handler */ +static int builtin_pwd(struct child_prog *dummy) +{ + getcwd(cwd, MAX_LINE); + puts(cwd); + return EXIT_SUCCESS; +} + +/* built-in 'read VAR' handler */ +static int builtin_read(struct child_prog *child) +{ + int res = 0, len, newlen; + char *s; + char string[MAX_READ]; + + if (child->argv[1]) { + /* argument (VAR) given: put "VAR=" into buffer */ + strcpy(string, child->argv[1]); + len = strlen(string); + string[len++] = '='; + string[len] = '\0'; + /* XXX would it be better to go through in_str? */ + fgets(&string[len], sizeof(string) - len, stdin); /* read string */ + newlen = strlen(string); + if(newlen > len) + string[--newlen] = '\0'; /* chomp trailing newline */ + /* + ** string should now contain "VAR=<value>" + ** copy it (putenv() won't do that, so we must make sure + ** the string resides in a static buffer!) + */ + res = -1; + if((s = strdup(string))) + res = putenv(s); + if (res) + fprintf(stderr, "read: %s\n", strerror(errno)); + } + else + fgets(string, sizeof(string), stdin); + + return (res); +} + +/* Built-in 'shift' handler */ +static int builtin_shift(struct child_prog *child) +{ + int n=1; + if (child->argv[1]) { + n=atoi(child->argv[1]); + } + if (n>=0 && n<global_argc) { + /* XXX This probably breaks $0 */ + global_argc -= n; + global_argv += n; + return EXIT_SUCCESS; + } else { + return EXIT_FAILURE; + } +} + +/* Built-in '.' handler (read-in and execute commands from file) */ +static int builtin_source(struct child_prog *child) +{ + FILE *input; + int status; + + if (child->argv[1] == NULL) + return EXIT_FAILURE; + + /* XXX search through $PATH is missing */ + input = fopen(child->argv[1], "r"); + if (!input) { + fprintf(stderr, "Couldn't open file '%s'\n", child->argv[1]); + return EXIT_FAILURE; + } + + /* Now run the file */ + /* XXX argv and argc are broken; need to save old global_argv + * (pointer only is OK!) on this stack frame, + * set global_argv=child->argv+1, recurse, and restore. */ + mark_open(fileno(input)); + status = parse_file_outer(input); + mark_closed(fileno(input)); + fclose(input); + return (status); +} + +static int builtin_ulimit(struct child_prog *child) +{ + printf("builtin_ulimit not written\n"); + return EXIT_FAILURE; +} + +static int builtin_umask(struct child_prog *child) +{ + printf("builtin_umask not written\n"); + return EXIT_FAILURE; +} + +/* built-in 'unset VAR' handler */ +static int builtin_unset(struct child_prog *child) +{ + if (child->argv[1] == NULL) { + fprintf(stderr, "unset: parameter required.\n"); + return EXIT_FAILURE; + } + unsetenv(child->argv[1]); + return EXIT_SUCCESS; +} + +static int b_check_space(o_string *o, int len) +{ + /* It would be easy to drop a more restrictive policy + * in here, such as setting a maximum string length */ + if (o->length + len > o->maxlen) { + char *old_data = o->data; + /* assert (data == NULL || o->maxlen != 0); */ + o->maxlen += max(2*len, B_CHUNK); + o->data = realloc(o->data, 1 + o->maxlen); + if (o->data == NULL) { + free(old_data); + } + } + return o->data == NULL; +} + +static int b_addchr(o_string *o, int ch) +{ + debug_printf("b_addchr: %c %d %p\n", ch, o->length, o); + if (b_check_space(o, 1)) return B_NOSPAC; + o->data[o->length] = ch; + o->length++; + o->data[o->length] = '\0'; + return 0; +} + +static void b_reset(o_string *o) +{ + o->length = 0; + o->nonnull = 0; + if (o->data != NULL) *o->data = '\0'; +} + +static void b_free(o_string *o) +{ + b_reset(o); + if (o->data != NULL) free(o->data); + o->data = NULL; + o->maxlen = 0; +} + +/* My analysis of quoting semantics tells me that state information + * is associated with a destination, not a source. + */ +static int b_addqchr(o_string *o, int ch, int quote) +{ + if (quote && strchr("*?[\\",ch)) { + int rc; + rc = b_addchr(o, '\\'); + if (rc) return rc; + } + return b_addchr(o, ch); +} + +/* belongs in utility.c */ +char *simple_itoa(unsigned int i) +{ + /* 21 digits plus null terminator, good for 64-bit or smaller ints */ + static char local[22]; + char *p = &local[21]; + *p-- = '\0'; + do { + *p-- = '0' + i % 10; + i /= 10; + } while (i > 0); + return p + 1; +} + +static int b_adduint(o_string *o, unsigned int i) +{ + int r; + char *p = simple_itoa(i); + /* no escape checking necessary */ + do r=b_addchr(o, *p++); while (r==0 && *p); + return r; +} + +static int static_get(struct in_str *i) +{ + int ch=*i->p++; + if (ch=='\0') return EOF; + return ch; +} + +static int static_peek(struct in_str *i) +{ + return *i->p; +} + +static inline void cmdedit_set_initial_prompt(void) +{ +#ifdef BB_FEATURE_SH_SIMPLE_PROMPT + PS1 = NULL; +#else + PS1 = getenv("PS1"); + if(PS1==0) + PS1 = "\\w \\$ "; +#endif +} + +static inline void setup_prompt_string(int promptmode, char **prompt_str) +{ +#ifdef BB_FEATURE_SH_SIMPLE_PROMPT + /* Set up the prompt */ + if (promptmode == 1) { + if (PS1) + free(PS1); + PS1=xmalloc(strlen(cwd)+4); + sprintf(PS1, "%s %s", cwd, ( geteuid() != 0 ) ? "$ ":"# "); + *prompt_str = PS1; + } else { + *prompt_str = PS2; + } +#else + *prompt_str = (promptmode==0)? PS1 : PS2; +#endif +} + +static void get_user_input(struct in_str *i) +{ + char *prompt_str; + static char the_command[MAX_LINE]; + + setup_prompt_string(i->promptmode, &prompt_str); +#ifdef BB_FEATURE_COMMAND_EDITING + /* + ** enable command line editing only while a command line + ** is actually being read; otherwise, we'll end up bequeathing + ** atexit() handlers and other unwanted stuff to our + ** child processes (rob@sysgo.de) + */ + cmdedit_read_input(prompt_str, the_command); + cmdedit_terminate(); +#else + fputs(prompt_str, stdout); + fflush(stdout); + the_command[0]=fgetc(i->file); + the_command[1]='\0'; +#endif + i->p = the_command; +} + +/* 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; + + ch = 0; + /* If there is data waiting, eat it up */ + if (i->p && *i->p) { + ch=*i->p++; + } else { + /* need to double check i->file because we might be doing something + * more complicated by now, like sourcing or substituting. */ + if (i->__promptme && interactive && i->file == stdin) { + get_user_input(i); + i->promptmode=2; + } + i->__promptme = 0; + + if (i->p && *i->p) { + ch=*i->p++; + } + debug_printf("b_getch: got a %d\n", ch); + } + if (ch == '\n') i->__promptme=1; + return ch; +} + +/* All the 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) +{ + if (i->p && *i->p) { + return *i->p; + } else { + static char buffer; + buffer = fgetc(i->file); + i->p = &buffer; + debug_printf("b_peek: got a %d\n", *i->p); + return *i->p; + } +} + +static void setup_file_in_str(struct in_str *i, FILE *f) +{ + i->peek = file_peek; + i->get = file_get; + i->__promptme=1; + i->promptmode=1; + 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; + i->__promptme=1; + i->promptmode=1; + i->p = s; +} + +static void mark_open(int fd) +{ + struct close_me *new = xmalloc(sizeof(struct close_me)); + new->fd = fd; + new->next = close_me_head; + close_me_head = new; +} + +static void mark_closed(int fd) +{ + struct close_me *tmp; + if (close_me_head == NULL || close_me_head->fd != fd) + error_msg_and_die("corrupt close_me"); + tmp = close_me_head; + close_me_head = close_me_head->next; + free(tmp); +} + +static void close_all() +{ + struct close_me *c; + for (c=close_me_head; c; c=c->next) { + close(c->fd); + } + close_me_head = NULL; +} + +/* squirrel != NULL means we squirrel away copies of stdin, stdout, + * and stderr if they are redirected. */ +static int setup_redirects(struct child_prog *prog, int squirrel[]) +{ + int openfd, mode; + struct redir_struct *redir; + + for (redir=prog->redirects; redir; redir=redir->next) { + if (redir->dup == -1) { + mode=redir_table[redir->type].mode; + openfd = open(redir->word.gl_pathv[0], mode, 0666); + 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!) */ + fprintf(stderr,"error opening %s: %s\n", redir->word.gl_pathv[0], + strerror(errno)); + return 1; + } + } else { + openfd = redir->dup; + } + + if (openfd != redir->fd) { + if (squirrel && redir->fd < 3) { + squirrel[redir->fd] = dup(redir->fd); + } + dup2(openfd, redir->fd); + 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) { + /* No error checking. I sure wouldn't know what + * to do with an error if I found one! */ + dup2(fd, i); + close(fd); + } + } +} + +/* XXX this definitely needs some more thought, work, and + * cribbing from other shells */ +static int pipe_wait(struct pipe *pi) +{ + int rcode=0, i, pid, running, status; + running = pi->num_progs; + while (running) { + pid=waitpid(-1, &status, 0); + if (pid < 0) perror_msg_and_die("waitpid"); + for (i=0; i < pi->num_progs; i++) { + if (pi->progs[i].pid == pid) { + if (i==pi->num_progs-1) rcode=WEXITSTATUS(status); + pi->progs[i].pid = 0; + running--; + break; + } + } + } + return rcode; +} + +/* very simple version for testing */ +static void pseudo_exec(struct child_prog *child) +{ + int rcode; + struct built_in_command *x; + if (child->argv) { + /* + * 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. + */ + for (x = bltins; x->cmd; x++) { + if (strcmp(child->argv[0], x->cmd) == 0 ) { + debug_printf("builtin exec %s\n", child->argv[0]); + exit(x->function(child)); + } + } + debug_printf("exec of %s\n",child->argv[0]); + execvp(child->argv[0],child->argv); + perror("execvp"); + exit(1); + } else if (child->group) { + debug_printf("runtime nesting to group\n"); + interactive=0; /* crucial!!!! */ + rcode = run_list_real(child->group); + /* OK to leak memory by not calling run_list_test, + * since this process is about to exit */ + exit(rcode); + } else { + /* Can happen. See what bash does with ">foo" by itself. */ + debug_printf("trying to pseudo_exec null command\n"); + exit(EXIT_SUCCESS); + } +} + +/* run_pipe_real() starts all the jobs, but doesn't wait for anything + * to finish. See pipe_wait(). + * + * 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_real returns, and the exit code is provided as the + * return value. + * + * The input of the pipe is always stdin, the output is always + * stdout. The outpipe[] mechanism in BusyBox-0.48 lash is bogus, + * because it tries to avoid running the command substitution in + * subshell, when that is in fact necessary. The subshell process + * now has its stdout directed to the input of the appropriate pipe, + * so this routine is noticeably simpler. + */ +static int run_pipe_real(struct pipe *pi) +{ + int i; + int nextin, nextout; + int pipefds[2]; /* pipefds[0] is for reading */ + struct child_prog *child; + struct built_in_command *x; + + nextin = 0; + pi->pgrp = 0; + + /* Check if this is a simple builtin (not part of a pipe). + * Builtins within pipes have to fork anyway, and are handled in + * pseudo_exec. "echo foo | read bar" doesn't work on bash, either. + */ + if (pi->num_progs == 1 && pi->progs[0].argv != NULL) { + child = & (pi->progs[0]); + if (child->group && ! child->subshell) { + int squirrel[] = {-1, -1, -1}; + int rcode; + debug_printf("non-subshell grouping\n"); + setup_redirects(child, squirrel); + /* XXX could we merge code with following builtin case, + * by creating a pseudo builtin that calls run_list_real? */ + rcode = run_list_real(child->group); + restore_redirects(squirrel); + return rcode; + } + for (x = bltins; x->cmd; x++) { + if (strcmp(child->argv[0], x->cmd) == 0 ) { + int squirrel[] = {-1, -1, -1}; + int rcode; + debug_printf("builtin inline %s\n", child->argv[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(child, squirrel); + rcode = x->function(child); + restore_redirects(squirrel); + return rcode; + } + } + } + + for (i = 0; i < pi->num_progs; i++) { + child = & (pi->progs[i]); + + /* pipes are inserted between pairs of commands */ + if ((i + 1) < pi->num_progs) { + if (pipe(pipefds)<0) perror_msg_and_die("pipe"); + nextout = pipefds[1]; + } else { + nextout=1; + pipefds[0] = -1; + } + + /* XXX test for failed fork()? */ + if (!(child->pid = fork())) { + close_all(); + + if (nextin != 0) { + dup2(nextin, 0); + close(nextin); + } + if (nextout != 1) { + dup2(nextout, 1); + close(nextout); + } + if (pipefds[0]!=-1) { + close(pipefds[0]); /* opposite end of our output pipe */ + } + + /* Like bash, explicit redirects override pipes, + * and the pipe fd is available for dup'ing. */ + setup_redirects(child,NULL); + + pseudo_exec(child); + } + if (interactive) { + /* Put our child in the process group whose leader is the + * first process in this pipe. */ + if (pi->pgrp==0) { + pi->pgrp = child->pid; + } + /* Don't check for errors. The child may be dead already, + * in which case setpgid returns error code EACCES. */ + setpgid(child->pid, pi->pgrp); + } + /* In the non-interactive case, do nothing. Leave the children + * with the process group that they inherited from us. */ + + if (nextin != 0) + close(nextin); + if (nextout != 1) + close(nextout); + + /* If there isn't another process, nextin is garbage + but it doesn't matter */ + nextin = pipefds[0]; + } + return -1; +} + +static int run_list_real(struct pipe *pi) +{ + int rcode=0; + int if_code=0, next_if_code=0; /* need double-buffer to handle elif */ + reserved_style rmode=RES_NONE; + for (;pi;pi=pi->next) { + rmode = pi->r_mode; + debug_printf("rmode=%d if_code=%d next_if_code=%d\n", rmode, if_code, next_if_code); + if (rmode == RES_THEN || rmode == RES_ELSE) if_code = next_if_code; + if (rmode == RES_THEN && if_code) continue; + if (rmode == RES_ELSE && !if_code) continue; + if (rmode == RES_ELIF && !if_code) continue; + if (pi->num_progs == 0) break; + rcode = run_pipe_real(pi); + if (rcode!=-1) { + /* We only ran a builtin: rcode was set by the return value + * of run_pipe_real(), and we don't need to wait for anything. */ + } else if (pi->followup==PIPE_BG) { + /* XXX check bash's behavior with nontrivial pipes */ + /* XXX compute jobid */ + /* XXX what does bash do with attempts to background builtins? */ + printf("[%d] %d\n", pi->jobid, pi->pgrp); + last_bg_pid = pi->pgrp; + rcode = EXIT_SUCCESS; + } else { + if (interactive) { + /* move the new process group into the foreground */ + /* suppress messages when run from /linuxrc mag@sysgo.de */ + signal(SIGTTIN, SIG_IGN); + signal(SIGTTOU, SIG_IGN); + if (tcsetpgrp(0, pi->pgrp) && errno != ENOTTY) + perror_msg("tcsetpgrp"); + rcode = pipe_wait(pi); + if (tcsetpgrp(0, getpid()) && errno != ENOTTY) + perror_msg("tcsetpgrp"); + signal(SIGTTIN, SIG_DFL); + signal(SIGTTOU, SIG_DFL); + } else { + rcode = pipe_wait(pi); + } + } + last_return_code=rcode; + if ( rmode == RES_IF || rmode == RES_ELIF ) + next_if_code=rcode; /* can be overwritten a number of times */ + if ( (rcode==EXIT_SUCCESS && pi->followup==PIPE_OR) || + (rcode!=EXIT_SUCCESS && pi->followup==PIPE_AND) ) + return rcode; /* XXX broken if list is part of if/then/else */ + } + return rcode; +} + +/* broken, of course, but OK for testing */ +static char *indenter(int i) +{ + static char blanks[]=" "; + return &blanks[sizeof(blanks)-i-1]; +} + +/* return code is the exit status of the pipe */ +static int run_pipe_test(struct pipe *pi, int indent) +{ + char **p; + struct child_prog *child; + struct redir_struct *r, *rnext; + int a, i, ret_code=0; + char *ind = indenter(indent); + final_printf("%s run pipe: (pid %d)\n",ind,getpid()); + for (i=0; i<pi->num_progs; i++) { + child = &pi->progs[i]; + final_printf("%s command %d:\n",ind,i); + if (child->argv) { + for (a=0,p=child->argv; *p; a++,p++) { + final_printf("%s argv[%d] = %s\n",ind,a,*p); + } + globfree(&child->glob_result); + child->argv=NULL; + } else if (child->group) { + final_printf("%s begin group (subshell:%d)\n",ind, child->subshell); + ret_code = run_list_test(child->group,indent+3); + final_printf("%s end group\n",ind); + } else { + final_printf("%s (nil)\n",ind); + } + for (r=child->redirects; r; r=rnext) { + final_printf("%s redirect %d%s", ind, r->fd, redir_table[r->type].descrip); + if (r->dup == -1) { + final_printf(" %s\n", *r->word.gl_pathv); + globfree(&r->word); + } else { + final_printf("&%d\n", r->dup); + } + rnext=r->next; + free(r); + } + child->redirects=NULL; + } + free(pi->progs); /* children are an array, they get freed all at once */ + pi->progs=NULL; + return ret_code; +} + +static int run_list_test(struct pipe *head, int indent) +{ + int rcode=0; /* if list has no members */ + struct pipe *pi, *next; + char *ind = indenter(indent); + for (pi=head; pi; pi=next) { + if (pi->num_progs == 0) break; + final_printf("%s pipe reserved mode %d\n", ind, pi->r_mode); + rcode = run_pipe_test(pi, indent); + final_printf("%s pipe followup code %d\n", ind, pi->followup); + next=pi->next; + pi->next=NULL; + free(pi); + } + return rcode; +} + +/* Select which version we will use */ +static int run_list(struct pipe *pi) +{ + int rcode=0; + if (fake_mode==0) { + rcode = run_list_real(pi); + } + /* run_list_test has the side effect of clearing memory + * In the long run that function can be merged with run_list_real, + * but doing that now would hobble the debugging effort. */ + run_list_test(pi,0); + return rcode; +} + +/* The API for glob is arguably broken. This routine pushes a non-matching + * string into the output structure, removing non-backslashed backslashes. + * If someone can prove me wrong, by performing this function within the + * original glob(3) api, feel free to rewrite this routine into oblivion. + * Return code (0 vs. GLOB_NOSPACE) matches glob(3). + * XXX broken if the last character is '\\', check that before calling. + */ +static int globhack(const char *src, int flags, glob_t *pglob) +{ + int cnt, pathc; + const char *s; + char *dest; + for (cnt=1, s=src; *s; s++) { + if (*s == '\\') s++; + cnt++; + } + dest = malloc(cnt); + if (!dest) return GLOB_NOSPACE; + if (!(flags & GLOB_APPEND)) { + pglob->gl_pathv=NULL; + pglob->gl_pathc=0; + pglob->gl_offs=0; + pglob->gl_offs=0; + } + pathc = ++pglob->gl_pathc; + pglob->gl_pathv = realloc(pglob->gl_pathv, (pathc+1)*sizeof(*pglob->gl_pathv)); + if (pglob->gl_pathv == NULL) return GLOB_NOSPACE; + pglob->gl_pathv[pathc-1]=dest; + pglob->gl_pathv[pathc]=NULL; + for (s=src; *s; s++, dest++) { + if (*s == '\\') s++; + *dest = *s; + } + *dest='\0'; + return 0; +} + +/* XXX broken if the last character is '\\', check that before calling */ +static int glob_needed(const char *s) +{ + for (; *s; s++) { + if (*s == '\\') s++; + if (strchr("*[?",*s)) return 1; + } + return 0; +} + +#if 0 +static void globprint(glob_t *pglob) +{ + int i; + debug_printf("glob_t at %p:\n", pglob); + debug_printf(" gl_pathc=%d gl_pathv=%p gl_offs=%d gl_flags=%d\n", + pglob->gl_pathc, pglob->gl_pathv, pglob->gl_offs, pglob->gl_flags); + for (i=0; i<pglob->gl_pathc; i++) + debug_printf("pglob->gl_pathv[%d] = %p = %s\n", i, + pglob->gl_pathv[i], pglob->gl_pathv[i]); +} +#endif + +static int xglob(o_string *dest, int flags, glob_t *pglob) +{ + int gr; + + /* short-circuit for null word */ + /* we can code this better when the debug_printf's are gone */ + if (dest->length == 0) { + if (dest->nonnull) { + /* bash man page calls this an "explicit" null */ + gr = globhack(dest->data, flags, pglob); + debug_printf("globhack returned %d\n",gr); + } else { + return 0; + } + } else if (glob_needed(dest->data)) { + gr = glob(dest->data, flags, NULL, pglob); + debug_printf("glob returned %d\n",gr); + if (gr == GLOB_NOMATCH) { + /* quote removal, or more accurately, backslash removal */ + gr = globhack(dest->data, flags, pglob); + debug_printf("globhack returned %d\n",gr); + } + } else { + gr = globhack(dest->data, flags, pglob); + debug_printf("globhack returned %d\n",gr); + } + if (gr == GLOB_NOSPACE) { + fprintf(stderr,"out of memory during glob\n"); + exit(1); + } + if (gr != 0) { /* GLOB_ABORTED ? */ + fprintf(stderr,"glob(3) error %d\n",gr); + } + /* globprint(glob_target); */ + return gr; +} + +/* 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 p_context *ctx, int fd, redir_type style, + struct in_str *input) +{ + struct child_prog *child=ctx->child; + struct redir_struct *redir = child->redirects; + struct redir_struct *last_redir=NULL; + + /* Create a new redir_struct and drop it onto the end of the linked list */ + while(redir) { + last_redir=redir; + redir=redir->next; + } + redir = xmalloc(sizeof(struct redir_struct)); + redir->next=NULL; + if (last_redir) { + last_redir->next=redir; + } else { + child->redirects=redir; + } + + redir->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); + + /* Check for a '2>&1' type redirect */ + redir->dup = redirect_dup_num(input); + if (redir->dup == -2) return 1; /* syntax error */ + if (redir->dup != -1) { + /* Erik had a check here that the file descriptor in question + * is legit; I postpone that to "run time" */ + 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; +} + +struct pipe *new_pipe(void) { + struct pipe *pi; + pi = xmalloc(sizeof(struct pipe)); + pi->num_progs = 0; + pi->progs = NULL; + pi->next = NULL; + pi->followup = 0; /* invalid */ + return pi; +} + +static void initialize_context(struct p_context *ctx) +{ + ctx->pipe=NULL; + ctx->pending_redirect=NULL; + ctx->child=NULL; + ctx->list_head=new_pipe(); + ctx->pipe=ctx->list_head; + ctx->w=RES_NONE; + ctx->stack=NULL; + done_command(ctx); /* creates the memory for working child */ +} + +/* normal return is 0 + * if a reserved word is found, and processed, return 1 + * should handle if, then, elif, else, fi, for, while, until, do, done. + * case, function, and select are obnoxious, save those for later. + */ +int reserved_word(o_string *dest, struct p_context *ctx) +{ + struct reserved_combo { + char *literal; + int code; + long flag; + }; + /* 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 struct reserved_combo reserved_list[] = { + { "if", RES_IF, FLAG_THEN | FLAG_START }, + { "then", RES_THEN, FLAG_ELIF | FLAG_ELSE | FLAG_FI }, + { "elif", RES_ELIF, FLAG_THEN }, + { "else", RES_ELSE, FLAG_FI }, + { "fi", RES_FI, FLAG_END }, + { "for", RES_FOR, FLAG_DO | FLAG_START }, + { "while", RES_WHILE, FLAG_DO | FLAG_START }, + { "until", RES_UNTIL, FLAG_DO | FLAG_START }, + { "do", RES_DO, FLAG_DONE }, + { "done", RES_DONE, FLAG_END } + }; + struct reserved_combo *r; + for (r=reserved_list; +#define NRES sizeof(reserved_list)/sizeof(struct reserved_combo) + r<reserved_list+NRES; r++) { + if (strcmp(dest->data, r->literal) == 0) { + debug_printf("found reserved word %s, code %d\n",r->literal,r->code); + if (r->flag & FLAG_START) { + struct p_context *new = xmalloc(sizeof(struct p_context)); + debug_printf("push stack\n"); + *new = *ctx; /* physical copy */ + initialize_context(ctx); + ctx->stack=new; + } else if ( ctx->w == RES_NONE || ! (ctx->old_flag & (1<<r->code))) { + syntax(); /* XXX how do we get out? */ + } + ctx->w=r->code; + ctx->old_flag = r->flag; + if (ctx->old_flag & FLAG_END) { + struct p_context *old; + debug_printf("pop stack\n"); + old = ctx->stack; + old->child->group = ctx->list_head; + *ctx = *old; /* physical copy */ + free(old); + ctx->w=RES_NONE; + } + b_reset (dest); + return 1; + } + } + return 0; +} + +/* normal return is 0. + * Syntax or xglob errors return 1. */ +static int done_word(o_string *dest, struct p_context *ctx) +{ + struct child_prog *child=ctx->child; + glob_t *glob_target; + int gr, flags = 0; + + debug_printf("done_word: %s %p\n", dest->data, child); + if (dest->length == 0 && !dest->nonnull) { + debug_printf(" true null, ignored\n"); + return 0; + } + if (ctx->pending_redirect) { + glob_target = &ctx->pending_redirect->word; + } else { + if (child->group) { + syntax(); + return 1; /* syntax error, groups and arglists don't mix */ + } + if (!child->argv) { + debug_printf("checking %s for reserved-ness\n",dest->data); + if (reserved_word(dest,ctx)) return 0; + } + glob_target = &child->glob_result; + if (child->argv) flags |= GLOB_APPEND; + } + gr = xglob(dest, flags, glob_target); + if (gr != 0) return 1; + + b_reset(dest); + if (ctx->pending_redirect) { + ctx->pending_redirect=NULL; + if (glob_target->gl_pathc != 1) { + fprintf(stderr, "ambiguous redirect\n"); + return 1; + } + } else { + child->argv = glob_target->gl_pathv; + } + return 0; +} + +/* The only possible error here is out of memory, in which case + * xmalloc exits. */ +static int done_command(struct p_context *ctx) +{ + /* The child is really already in the pipe structure, so + * advance the pipe counter and make a new, null child. + * Only real trickiness here is that the uncommitted + * child structure, to which ctx->child points, is not + * counted in pi->num_progs. */ + struct pipe *pi=ctx->pipe; + struct child_prog *prog=ctx->child; + + if (prog && prog->group == NULL + && prog->argv == NULL + && prog->redirects == NULL) { + debug_printf("done_command: skipping null command\n"); + return 0; + } else if (prog) { + pi->num_progs++; + debug_printf("done_command: num_progs incremented to %d\n",pi->num_progs); + } else { + debug_printf("done_command: initializing\n"); + } + pi->progs = xrealloc(pi->progs, sizeof(*pi->progs) * (pi->num_progs+1)); + + prog = pi->progs + pi->num_progs; + prog->redirects = NULL; + prog->argv = NULL; + prog->is_stopped = 0; + prog->group = NULL; + prog->glob_result.gl_pathv = NULL; + prog->family = pi; + + ctx->child=prog; + /* but ctx->pipe and ctx->list_head remain unchanged */ + return 0; +} + +static int done_pipe(struct p_context *ctx, pipe_style type) +{ + struct pipe *new_p; + done_command(ctx); /* implicit closure of previous command */ + debug_printf("done_pipe, type %d\n", type); + ctx->pipe->followup = type; + ctx->pipe->r_mode = ctx->w; + new_p=new_pipe(); + ctx->pipe->next = new_p; + ctx->pipe = new_p; + ctx->child = NULL; + done_command(ctx); /* set up new pipe to accept commands */ + return 0; +} + +/* 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. + * returns 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 = b_peek(input); + if (ch != '&') return -1; + + b_getch(input); /* get the & */ + while (ch=b_peek(input),isdigit(ch)) { + d = d*10+(ch-'0'); + ok=1; + b_getch(input); + } + if (ok) return d; + + fprintf(stderr, "ambiguous redirect\n"); + return -2; +} + +/* 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; + } + } + /* reuse num (and save an int) */ + num=atoi(o->data); + b_reset(o); + return num; +} + +FILE *generate_stream_from_list(struct pipe *head) +{ + FILE *pf; +#if 1 + int pid, channel[2]; + if (pipe(channel)<0) perror_msg_and_die("pipe"); + pid=fork(); + if (pid<0) { + perror_msg_and_die("fork"); + } else if (pid==0) { + close(channel[0]); + if (channel[1] != 1) { + dup2(channel[1],1); + close(channel[1]); + } +#if 0 +#define SURROGATE "surrogate response" + write(1,SURROGATE,sizeof(SURROGATE)); + exit(run_list(head)); +#else + exit(run_list_real(head)); /* leaks memory */ +#endif + } + debug_printf("forked child %d\n",pid); + close(channel[1]); + pf = fdopen(channel[0],"r"); + debug_printf("pipe on FILE *%p\n",pf); +#else + run_list_test(head,0); + pf=popen("echo surrogate response","r"); + debug_printf("started fake pipe on FILE *%p\n",pf); +#endif + return pf; +} + +/* this version hacked for testing purposes */ +/* return code is exit status of the process that is run. */ +static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end) +{ + int retcode; + o_string result=NULL_O_STRING; + struct p_context inner; + FILE *p; + struct in_str pipe_str; + initialize_context(&inner); + + /* recursion to generate command */ + retcode = parse_stream(&result, &inner, input, subst_end); + if (retcode != 0) return retcode; /* syntax error or EOF */ + done_word(&result, &inner); + done_pipe(&inner, PIPE_SEQ); + b_free(&result); + + p=generate_stream_from_list(inner.list_head); + if (p==NULL) return 1; + mark_open(fileno(p)); + setup_file_in_str(&pipe_str, p); + + /* now send results of command back into original context */ + retcode = parse_stream(dest, ctx, &pipe_str, '\0'); + /* XXX In case of a syntax error, should we try to kill the child? + * That would be tough to do right, so just read until EOF. */ + if (retcode == 1) { + while (b_getch(&pipe_str)!=EOF) { /* discard */ }; + } + + debug_printf("done reading from pipe, pclose()ing\n"); + /* This is the step that wait()s for the child. Should be pretty + * safe, since we just read an EOF from its stdout. We could try + * to better, by using wait(), and keeping track of background jobs + * at the same time. That would be a lot of work, and contrary + * to the KISS philosophy of this program. */ + mark_closed(fileno(p)); + retcode=pclose(p); + debug_printf("pclosed, retcode=%d\n",retcode); + /* XXX this process fails to trim a single trailing newline */ + return retcode; +} + +static int parse_group(o_string *dest, struct p_context *ctx, + struct in_str *input, int ch) +{ + int rcode, endch=0; + struct p_context sub; + struct child_prog *child = ctx->child; + if (child->argv) { + syntax(); + return 1; /* syntax error, groups and arglists don't mix */ + } + initialize_context(&sub); + switch(ch) { + case '(': endch=')'; child->subshell=1; break; + case '{': endch='}'; break; + default: syntax(); /* really logic error */ + } + rcode=parse_stream(dest,&sub,input,endch); + done_word(dest,&sub); /* finish off the final word in the subcontext */ + done_pipe(&sub, PIPE_SEQ); /* and the final command there, too */ + child->group = sub.list_head; + return rcode; + /* child remains "open", available for possible redirects */ +} + +/* basically useful version until someone wants to get fancier, + * see the bash man page under "Parameter Expansion" */ +static void lookup_param(o_string *dest, struct p_context *ctx, o_string *src) +{ + const char *p=NULL; + if (src->data) p = getenv(src->data); + if (p) parse_string(dest, ctx, p); /* recursion */ + b_free(src); +} + +/* return code: 0 for OK, 1 for syntax error */ +static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input) +{ + int i, advance=0; + o_string alt=NULL_O_STRING; + char sep[]=" "; + int ch = input->peek(input); /* first character after the $ */ + debug_printf("handle_dollar: ch=%c\n",ch); + if (isalpha(ch)) { + while(ch=b_peek(input),isalnum(ch) || ch=='_') { + b_getch(input); + b_addchr(&alt,ch); + } + lookup_param(dest, ctx, &alt); + } else if (isdigit(ch)) { + i = ch-'0'; /* XXX is $0 special? */ + if (i<global_argc) { + parse_string(dest, ctx, global_argv[i]); /* recursion */ + } + advance = 1; + } else switch (ch) { + case '$': + b_adduint(dest,getpid()); + advance = 1; + break; + case '!': + if (last_bg_pid > 0) b_adduint(dest, last_bg_pid); + advance = 1; + break; + case '?': + b_adduint(dest,last_return_code); + advance = 1; + break; + case '#': + b_adduint(dest,global_argc ? global_argc-1 : 0); + advance = 1; + break; + case '{': + b_getch(input); + /* XXX maybe someone will try to escape the '}' */ + while(ch=b_getch(input),ch!=EOF && ch!='}') { + b_addchr(&alt,ch); + } + if (ch != '}') { + syntax(); + return 1; + } + lookup_param(dest, ctx, &alt); + break; + case '(': + process_command_subs(dest, ctx, input, ')'); + break; + case '*': + sep[0]=ifs[0]; + for (i=1; i<global_argc; i++) { + parse_string(dest, ctx, global_argv[i]); + if (i+1 < global_argc) parse_string(dest, ctx, sep); + } + break; + case '@': + case '-': + case '_': + /* still unhandled, but should be eventually */ + fprintf(stderr,"unhandled syntax: $%c\n",ch); + return 1; + break; + default: + b_addqchr(dest,'$',dest->quote); + } + /* Eat the character if the flag was set. If the compiler + * is smart enough, we could substitute "b_getch(input);" + * for all the "advance = 1;" above, and also end up with + * a nice size-optimized program. Hah! That'll be the day. + */ + if (advance) b_getch(input); + return 0; +} + +int parse_string(o_string *dest, struct p_context *ctx, const char *src) +{ + struct in_str foo; + setup_string_in_str(&foo, src); + return parse_stream(dest, ctx, &foo, '\0'); +} + +/* return code is 0 for normal exit, 1 for syntax error */ +int parse_stream(o_string *dest, struct p_context *ctx, + struct in_str *input, int end_trigger) +{ + unsigned int ch, m; + int redir_fd; + redir_type redir_style; + int next; + + /* Only double-quote state is handled in the state variable dest->quote. + * A single-quote triggers a bypass of the main loop until its mate is + * found. When recursing, quote state is passed in via dest->quote. */ + + debug_printf("parse_stream, end_trigger=%d\n",end_trigger); + while ((ch=b_getch(input))!=EOF) { + m = map[ch]; + next = (ch == '\n') ? 0 : b_peek(input); + debug_printf("parse_stream: ch=%c (%d) m=%d quote=%d\n", + ch,ch,m,dest->quote); + if (m==0 || ((m==1 || m==2) && dest->quote)) { + b_addqchr(dest, ch, dest->quote); + } else if (ch == end_trigger && !dest->quote) { + debug_printf("leaving parse_stream\n"); + return 0; + } else if (m==2 && !dest->quote) { /* IFS */ + done_word(dest, ctx); +#if 0 + if (ch=='\n') { + /* Yahoo! Time to run with it! */ + done_pipe(ctx,PIPE_SEQ); + run_list(ctx->list_head); + initialize_context(ctx); + } +#endif + } else switch (ch) { + case '#': + if (dest->length == 0 && !dest->quote) { + while(ch=b_peek(input),ch!=EOF && ch!='\n') { b_getch(input); } + } else { + b_addqchr(dest, ch, dest->quote); + } + break; + case '\\': + if (next == EOF) { + syntax(); + return 1; + } + b_addqchr(dest, '\\', dest->quote); + b_addqchr(dest, b_getch(input), dest->quote); + break; + case '$': + if (handle_dollar(dest, ctx, input)!=0) return 1; + break; + case '\'': + dest->nonnull = 1; + while(ch=b_getch(input),ch!=EOF && ch!='\'') { + b_addchr(dest,ch); + } + if (ch==EOF) { + syntax(); + return 1; + } + break; + case '"': + dest->nonnull = 1; + dest->quote = !dest->quote; + break; + case '`': + process_command_subs(dest, ctx, input, '`'); + break; + case '>': + redir_fd = redirect_opt_num(dest); + done_word(dest, ctx); + redir_style=REDIRECT_OVERWRITE; + if (next == '>') { + redir_style=REDIRECT_APPEND; + b_getch(input); + } else if (next == '(') { + syntax(); /* until we support >(list) Process Substitution */ + return 1; + } + setup_redirect(ctx, redir_fd, redir_style, input); + break; + case '<': + redir_fd = redirect_opt_num(dest); + done_word(dest, ctx); + redir_style=REDIRECT_INPUT; + if (next == '<') { + redir_style=REDIRECT_HEREIS; + b_getch(input); + } else if (next == '>') { + redir_style=REDIRECT_IO; + b_getch(input); + } else if (next == '(') { + syntax(); /* until we support <(list) Process Substitution */ + return 1; + } + setup_redirect(ctx, redir_fd, redir_style, input); + break; + case ';': + done_word(dest, ctx); + done_pipe(ctx,PIPE_SEQ); + break; + case '&': + done_word(dest, ctx); + if (next=='&') { + b_getch(input); + done_pipe(ctx,PIPE_AND); + } else { + done_pipe(ctx,PIPE_BG); + } + break; + case '|': + done_word(dest, ctx); + if (next=='|') { + b_getch(input); + 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); + } + break; + case '(': + case '{': + if (parse_group(dest, ctx, input, ch)!=0) return 1; + break; + case ')': + case '}': + syntax(); /* Proper use of this character caught by end_trigger */ + return 1; + break; + default: + syntax(); /* this is really an internal logic error */ + return 1; + } + } + /* complain if quote? No, maybe we just finished a command substitution + * that was quoted. Example: + * $ echo "`cat foo` plus more" + * and we just got the EOF generated by the subshell that ran "cat foo" + * The only real complaint is if we got an EOF when end_trigger != '\0', + * that is, we were really supposed to get end_trigger, and never got + * one before the EOF. Can't use the standard "syntax error" return code, + * so that parse_stream_outer can distinguish the EOF and exit smoothly. */ + if (end_trigger != '\0') return -1; + return 0; +} + +void mapset(const unsigned char *set, int code) +{ + const unsigned char *s; + for (s=set; *s; s++) map[*s] = code; +} + +void update_ifs_map(void) +{ + /* char *ifs and char map[256] are both globals. */ + ifs = getenv("IFS"); + if (ifs == NULL) ifs=" \t\n"; + /* Precompute a list of 'flow through' behavior so it can be treated + * quickly up front. Computation is necessary because of IFS. + * Special case handling of IFS == " \t\n" is not implemented. + * The map[] array only really needs two bits each, and on most machines + * that would be faster because of the reduced L1 cache footprint. + */ + memset(map,0,256); /* most characters flow through always */ + mapset("\\$'\"`", 3); /* never flow through */ + mapset("<>;&|(){}#", 1); /* flow through if quoted */ + mapset(ifs, 2); /* also flow through if quoted */ +} + +/* most recursion does not come through here, the exeception is + * from builtin_source() */ +int parse_stream_outer(struct in_str *inp) +{ + + struct p_context ctx; + o_string temp=NULL_O_STRING; + int rcode; + do { + initialize_context(&ctx); + update_ifs_map(); + inp->promptmode=1; + rcode = parse_stream(&temp, &ctx, inp, '\n'); + done_word(&temp, &ctx); + done_pipe(&ctx,PIPE_SEQ); + run_list(ctx.list_head); + } while (rcode != -1); /* loop on syntax errors, return on EOF */ + return 0; +} + +static int parse_string_outer(const char *s) +{ + struct in_str input; + setup_string_in_str(&input, s); + return parse_stream_outer(&input); +} + +static int parse_file_outer(FILE *f) +{ + int rcode; + struct in_str input; + setup_file_in_str(&input, f); + rcode = parse_stream_outer(&input); + return rcode; +} + +int shell_main(int argc, char **argv) +{ + int opt; + FILE *input; + + /* XXX what should these be while sourcing /etc/profile? */ + global_argc = argc; + global_argv = argv; + + if (argv[0] && argv[0][0] == '-') { + debug_printf("\nsourcing /etc/profile\n"); + input = xfopen("/etc/profile", "r"); + mark_open(fileno(input)); + parse_file_outer(input); + mark_closed(fileno(input)); + fclose(input); + } + input=stdin; + + /* initialize the cwd -- this is never freed...*/ + cwd = xgetcwd(0); +#ifdef BB_FEATURE_COMMAND_EDITING + cmdedit_set_initial_prompt(); +#else + PS1 = NULL; +#endif + + while ((opt = getopt(argc, argv, "c:xif")) > 0) { + switch (opt) { + case 'c': + { + global_argv = argv+optind; + global_argc = argc-optind; + opt = parse_string_outer(optarg); + exit(opt); + } + break; + case 'i': + interactive++; + break; + case 'f': + fake_mode++; + break; + default: + fprintf(stderr, "Usage: sh [FILE]...\n" + " or: sh -c command [args]...\n\n"); + exit(EXIT_FAILURE); + } + } + /* A shell is interactive if the `-i' flag was given, or if all of + * the following conditions are met: + * no -c command + * no arguments remaining or the -s flag given + * standard input is a terminal + * standard output is a terminal + * Refer to Posix.2, the description of the `sh' utility. */ + if (argv[optind]==NULL && input==stdin && + isatty(fileno(stdin)) && isatty(fileno(stdout))) { + interactive++; + } + + if (interactive) { + /* Looks like they want an interactive shell */ + fprintf(stdout, "\nhush -- the humble shell v0.01 (testing)\n\n"); + exit(parse_file_outer(stdin)); + } + debug_printf("\ninteractive=%d\n", interactive); + + debug_printf("\nrunning script '%s'\n", argv[optind]); + global_argv = argv+optind; + global_argc = argc-optind; + input = xfopen(argv[optind], "r"); + opt = parse_file_outer(input); + +#ifdef BB_FEATURE_CLEAN_UP + fclose(input.file); +#endif + + return(opt); +} |