diff options
Diffstat (limited to 'shell/hush.c')
| -rw-r--r-- | shell/hush.c | 188 |
1 files changed, 125 insertions, 63 deletions
diff --git a/shell/hush.c b/shell/hush.c index 5794b1d..b515eab 100644 --- a/shell/hush.c +++ b/shell/hush.c @@ -78,6 +78,7 @@ * Licensed under the GPL v2 or later, see the file LICENSE in this tarball. */ #include "busybox.h" /* for APPLET_IS_NOFORK/NOEXEC */ +#include <malloc.h> /* for malloc_trim */ #include <glob.h> /* #include <dmalloc.h> */ #if ENABLE_HUSH_CASE @@ -786,7 +787,7 @@ static void xxfree(void *ptr) * HUSH_DEBUG >= 2 prints line number in this file where it was detected. */ #if HUSH_DEBUG < 2 -# define die_if_script(lineno, fmt...) die_if_script(fmt) +# define die_if_script(lineno, ...) die_if_script(__VA_ARGS__) # define syntax_error(lineno, msg) syntax_error(msg) # define syntax_error_at(lineno, msg) syntax_error_at(msg) # define syntax_error_unterm_ch(lineno, ch) syntax_error_unterm_ch(ch) @@ -855,7 +856,7 @@ static void syntax_error_unexpected_ch(unsigned lineno, int ch) # undef syntax_error_unterm_str # undef syntax_error_unexpected_ch #else -# define die_if_script(fmt...) die_if_script(__LINE__, fmt) +# define die_if_script(...) die_if_script(__LINE__, __VA_ARGS__) # define syntax_error(msg) syntax_error(__LINE__, msg) # define syntax_error_at(msg) syntax_error_at(__LINE__, msg) # define syntax_error_unterm_ch(ch) syntax_error_unterm_ch(__LINE__, ch) @@ -898,7 +899,7 @@ static int is_well_formed_var_name(const char *s, char terminator) /* Replace each \x with x in place, return ptr past NUL. */ static char *unbackslash(char *src) { - char *dst = src; + char *dst = src = strchrnul(src, '\\'); while (1) { if (*src == '\\') src++; @@ -1037,7 +1038,7 @@ static void restore_G_args(save_arg_t *sv, char **argv) * 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 + * ^C or ^Z from keyboard seems to execute "at once" because it usually * backgrounds (i.e. stops) or kills all members of currently running * pipe. * @@ -1104,12 +1105,17 @@ static void restore_G_args(save_arg_t *sv, char **argv) * (child shell is not interactive), * unset all traps (note: regardless of child shell's type - {}, (), etc) * after [v]fork, if we plan to exec: - * POSIX says pending signal mask is cleared in child - no need to clear it. + * POSIX says fork clears pending signal mask 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 * and to restore tty pgrp on signal-induced exit. + * + * Note 2 (compat): + * Standard says "When a subshell is entered, traps that are not being ignored + * are set to the default actions". bash interprets it so that traps which + * are set to "" (ignore) are NOT reset to defaults. We do the same. */ enum { SPECIAL_INTERACTIVE_SIGS = 0 @@ -2596,43 +2602,51 @@ static void reset_traps_to_defaults(void) { /* This function is always called in a child shell * after fork (not vfork, NOMMU doesn't use this function). - * Child shells are not interactive. - * SIGTTIN/SIGTTOU/SIGTSTP should not have special handling. - * Testcase: (while :; do :; done) + ^Z should background. - * Same goes for SIGTERM, SIGHUP, SIGINT. */ unsigned sig; unsigned mask; + /* Child shells are not interactive. + * SIGTTIN/SIGTTOU/SIGTSTP should not have special handling. + * Testcase: (while :; do :; done) + ^Z should background. + * Same goes for SIGTERM, SIGHUP, SIGINT. + */ if (!G.traps && !(G.non_DFL_mask & SPECIAL_INTERACTIVE_SIGS)) - return; + return; /* already no traps and no SPECIAL_INTERACTIVE_SIGS */ - /* Stupid. It can be done with *single* &= op, but we can't use - * the fact that G.blocked_set is implemented as a bitmask... */ + /* Switching off SPECIAL_INTERACTIVE_SIGS. + * Stupid. It can be done with *single* &= op, but we can't use + * the fact that G.blocked_set is implemented as a bitmask + * in libc... */ mask = (SPECIAL_INTERACTIVE_SIGS >> 1); sig = 1; while (1) { - if (mask & 1) - sigdelset(&G.blocked_set, sig); + if (mask & 1) { + /* Careful. Only if no trap or trap is not "" */ + if (!G.traps || !G.traps[sig] || G.traps[sig][0]) + sigdelset(&G.blocked_set, sig); + } mask >>= 1; if (!mask) break; sig++; } - + /* Our homegrown sig mask is saner to work with :) */ G.non_DFL_mask &= ~SPECIAL_INTERACTIVE_SIGS; + + /* Resetting all traps to default except empty ones */ mask = G.non_DFL_mask; if (G.traps) for (sig = 0; sig < NSIG; sig++, mask >>= 1) { - if (!G.traps[sig]) + if (!G.traps[sig] || !G.traps[sig][0]) 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. + /* There was a trap handler, we just removed it. * But if sig still has non-DFL handling, - * we should not unblock it. */ + * we should not unblock the sig. */ if (mask & 1) continue; sigdelset(&G.blocked_set, sig); @@ -3079,15 +3093,21 @@ static const struct built_in_command* find_builtin(const char *name) } #if ENABLE_HUSH_FUNCTIONS -static const struct function *find_function(const char *name) +static struct function **find_function_slot(const char *name) { - const struct function *funcp = G.top_func; - while (funcp) { - if (strcmp(name, funcp->name) == 0) { + struct function **funcpp = &G.top_func; + while (*funcpp) { + if (strcmp(name, (*funcpp)->name) == 0) { break; } - funcp = funcp->next; + funcpp = &(*funcpp)->next; } + return funcpp; +} + +static const struct function *find_function(const char *name) +{ + const struct function *funcp = *find_function_slot(name); if (funcp) debug_printf_exec("found function '%s'\n", name); return funcp; @@ -3096,18 +3116,11 @@ static const struct function *find_function(const char *name) /* Note: takes ownership on name ptr */ static struct function *new_function(char *name) { - struct function *funcp; - struct function **funcpp = &G.top_func; + struct function **funcpp = find_function_slot(name); + struct function *funcp = *funcpp; - while ((funcp = *funcpp) != NULL) { - struct command *cmd; - - if (strcmp(funcp->name, name) != 0) { - funcpp = &funcp->next; - continue; - } - - cmd = funcp->parent_cmd; + if (funcp != NULL) { + struct command *cmd = funcp->parent_cmd; debug_printf_exec("func %p parent_cmd %p\n", funcp, cmd); if (!cmd) { debug_printf_exec("freeing & replacing function '%s'\n", funcp->name); @@ -3129,39 +3142,36 @@ static struct function *new_function(char *name) cmd->group_as_string = funcp->body_as_string; # endif } - goto skip; + } else { + debug_printf_exec("remembering new function '%s'\n", name); + funcp = *funcpp = xzalloc(sizeof(*funcp)); + /*funcp->next = NULL;*/ } - debug_printf_exec("remembering new function '%s'\n", name); - funcp = *funcpp = xzalloc(sizeof(*funcp)); - /*funcp->next = NULL;*/ - skip: + funcp->name = name; return funcp; } static void unset_func(const char *name) { - struct function *funcp; - struct function **funcpp = &G.top_func; - - while ((funcp = *funcpp) != NULL) { - if (strcmp(funcp->name, name) == 0) { - *funcpp = funcp->next; - /* funcp is unlinked now, deleting it. - * Note: if !funcp->body, the function was created by - * "-F name body", do not free ->body_as_string - * and ->name as they were not malloced. */ - if (funcp->body) { - free_pipe_list(funcp->body); - free(funcp->name); + struct function **funcpp = find_function_slot(name); + struct function *funcp = *funcpp; + + if (funcp != NULL) { + debug_printf_exec("freeing function '%s'\n", funcp->name); + *funcpp = funcp->next; + /* funcp is unlinked now, deleting it. + * Note: if !funcp->body, the function was created by + * "-F name body", do not free ->body_as_string + * and ->name as they were not malloced. */ + if (funcp->body) { + free_pipe_list(funcp->body); + free(funcp->name); # if !BB_MMU - free(funcp->body_as_string); + free(funcp->body_as_string); # endif - } - free(funcp); - break; } - funcpp = &funcp->next; + free(funcp); } } @@ -3628,9 +3638,9 @@ static int checkjobs(struct pipe* fg_pipe) /* Note: is WIFSIGNALED, WEXITSTATUS = sig + 128 */ rcode = WEXITSTATUS(status); IF_HAS_KEYWORDS(if (fg_pipe->pi_inverted) rcode = !rcode;) - /* bash prints killing signal's name for *last* + /* bash prints killer signal's name for *last* * process in pipe (prints just newline for SIGINT). - * Mimic this. Example: "sleep 5" + ^\ + * Mimic this. Example: "sleep 5" + (^\ or kill -QUIT) */ if (WIFSIGNALED(status)) { int sig = WTERMSIG(status); @@ -5183,6 +5193,47 @@ static FILE *generate_stream_from_string(const char *s) xmove_fd(channel[1], 1); /* Prevent it from trying to handle ctrl-z etc */ IF_HUSH_JOB(G.run_list_level = 1;) + /* Awful hack for `trap` or $(trap). + * + * http://www.opengroup.org/onlinepubs/009695399/utilities/trap.html + * contains an example where "trap" is executed in a subshell: + * + * save_traps=$(trap) + * ... + * eval "$save_traps" + * + * Standard does not say that "trap" in subshell shall print + * parent shell's traps. It only says that its output + * must have suitable form, but then, in the above example + * (which is not supposed to be normative), it implies that. + * + * bash (and probably other shell) does implement it + * (traps are reset to defaults, but "trap" still shows them), + * but as a result, "trap" logic is hopelessly messed up: + * + * # trap + * trap -- 'echo Ho' SIGWINCH <--- we have a handler + * # (trap) <--- trap is in subshell - no output (correct, traps are reset) + * # true | trap <--- trap is in subshell - no output (ditto) + * # echo `true | trap` <--- in subshell - output (but traps are reset!) + * trap -- 'echo Ho' SIGWINCH + * # echo `(trap)` <--- in subshell in subshell - output + * trap -- 'echo Ho' SIGWINCH + * # echo `true | (trap)` <--- in subshell in subshell in subshell - output! + * trap -- 'echo Ho' SIGWINCH + * + * The rules when to forget and when to not forget traps + * get really complex and nonsensical. + * + * Our solution: ONLY bare $(trap) or `trap` is special. + */ + s = skip_whitespace(s); + if (strncmp(s, "trap", 4) == 0 && (*skip_whitespace(s + 4) == '\0')) + { + static const char *const argv[] = { NULL, NULL }; + builtin_trap((char**)argv); + exit(0); /* not _exit() - we need to fflush */ + } #if BB_MMU reset_traps_to_defaults(); parse_and_run_string(s); @@ -5676,8 +5727,10 @@ static int handle_dollar(o_string *as_string, goto make_var; } /* else: it's $_ */ - /* TODO: */ - /* $_ Shell or shell script name; or last cmd name */ + /* TODO: $_ and $-: */ + /* $_ Shell or shell script name; or last argument of last command + * (if last command wasn't a pipe; if it was, bash sets $_ to ""); + * but in command's env, set to full pathname used to invoke it */ /* $- Option flags set by set builtin or shell options (-i etc) */ default: o_addQchr(dest, '$'); @@ -5794,7 +5847,7 @@ static struct pipe *parse_stream(char **pstring, * 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'); + end_trigger ? end_trigger : 'X'); debug_enter(); G.ifs = get_local_var_value("IFS"); @@ -6860,7 +6913,8 @@ static int FAST_FUNC builtin_cd(char **argv) * bash says "bash: cd: HOME not set" and does nothing * (exitcode 1) */ - newdir = get_local_var_value("HOME") ? : "/"; + const char *home = get_local_var_value("HOME"); + newdir = home ? home : "/"; } if (chdir(newdir)) { /* Mimic bash message exactly */ @@ -7057,6 +7111,10 @@ static int FAST_FUNC builtin_trap(char **argv) if (G.traps[i]) { printf("trap -- "); print_escaped(G.traps[i]); + /* note: bash adds "SIG", but only if invoked + * as "bash". If called as "sh", or if set -o posix, + * then it prints short signal names. + * We are printing short names: */ printf(" %s\n", get_signame(i)); } } @@ -7268,6 +7326,10 @@ static int FAST_FUNC builtin_memleak(char **argv UNUSED_PARAM) void *p; unsigned long l; +#ifdef M_TRIM_THRESHOLD + /* Optional. Reduces probability of false positives */ + malloc_trim(0); +#endif /* Crude attempt to find where "free memory" starts, * sans fragmentation. */ p = malloc(240); |