From 22d10a029283b93c31890366a1f8dcfc59e6298c Mon Sep 17 00:00:00 2001 From: Denis Vlasenko Date: Mon, 13 Oct 2008 08:53:43 +0000 Subject: hush: fix trashing of environment by local env vars: a=a; a=b cmd; - a was unset! +57 bytes function old new delta add_string_to_strings - 110 +110 putenv_all - 27 +27 run_list 2086 2111 +25 free_strings - 7 +7 free_pipe 210 208 -2 add_malloced_string_to_strings 110 - -110 ------------------------------------------------------------------------------ (add/remove: 3/1 grow/shrink: 1/1 up/down: 169/-112) Total: 57 bytes --- shell/hush.c | 164 +++++++++++++++++++++++++++++++++++++---------------------- 1 file changed, 104 insertions(+), 60 deletions(-) (limited to 'shell/hush.c') diff --git a/shell/hush.c b/shell/hush.c index 7cf2f3322..b62350404 100644 --- a/shell/hush.c +++ b/shell/hush.c @@ -614,7 +614,7 @@ static char *unbackslash(char *src) return dst; } -static char **add_malloced_strings_to_strings(char **strings, char **add) +static char **add_strings_to_strings(char **strings, char **add) { int i; unsigned count1; @@ -643,14 +643,37 @@ static char **add_malloced_strings_to_strings(char **strings, char **add) return v; } -static char **add_malloced_string_to_strings(char **strings, char *add) +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); +} + +static void putenv_all(char **strings) +{ + if (!strings) + return; + while (*strings) + putenv(*strings++); +} + +static char **putenv_all_and_save_old(char **strings) +{ + char **old = NULL; + char **s = strings; - return add_malloced_strings_to_strings(strings, v); + if (!strings) + return old; + while (*strings) { + char *v = getenv(*strings++); + if (!v) + continue; + old = add_string_to_strings(old, v); + } + putenv_all(s); + return old; } static void free_strings_and_unsetenv(char **strings, int unset) @@ -1432,7 +1455,7 @@ static void pseudo_exec_argv(char ***ptr_ptrs2free, char **argv, int assignment_ p = expand_string_to_string(*argv); putenv(p); #if !BB_MMU - *ptr_ptrs2free = add_malloced_string_to_strings(*ptr_ptrs2free, p); + *ptr_ptrs2free = add_string_to_strings(*ptr_ptrs2free, p); #endif argv++; } @@ -1442,8 +1465,8 @@ static void pseudo_exec_argv(char ***ptr_ptrs2free, char **argv, int assignment_ argv = expand_strvec_to_strvec(argv); #if !BB_MMU /* Inserting magic guard pointer to not unsetenv junk later */ - *ptr_ptrs2free = add_malloced_string_to_strings(*ptr_ptrs2free, (char*)hush_version_str); - *ptr_ptrs2free = add_malloced_string_to_strings(*ptr_ptrs2free, (char*)argv); + *ptr_ptrs2free = add_string_to_strings(*ptr_ptrs2free, (char*)hush_version_str); + *ptr_ptrs2free = add_string_to_strings(*ptr_ptrs2free, (char*)argv); #endif } @@ -1762,14 +1785,24 @@ static int checkjobs_and_fg_shell(struct pipe* fg_pipe) * Returns -1 only if started some children. IOW: we have to * mask out retvals of builtins etc with 0xff! */ +/* A little helper first */ +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; +} static int run_pipe(struct pipe *pi) { int i; int nextin; int pipefds[2]; /* pipefds[0] is for reading */ struct command *command; - char **ptrs2free = NULL; - char **argv_expanded = NULL; + char **argv_expanded; char **argv; const struct built_in_command *x; char *p; @@ -1791,6 +1824,7 @@ static int run_pipe(struct pipe *pi) * pseudo_exec. "echo foo | read bar" doesn't work on bash, either. */ command = &(pi->cmds[0]); + if (single_and_fg && command->group && command->subshell == 0) { debug_printf("non-subshell grouping\n"); setup_redirects(command, squirrel); @@ -1803,8 +1837,12 @@ static int run_pipe(struct pipe *pi) } argv = command->argv; + argv_expanded = NULL; if (single_and_fg && argv != NULL) { + char **new_env = NULL; + char **old_env = NULL; + i = command->assignment_cnt; if (i != 0 && argv[i] == NULL) { /* assignments, but no command: set local environment */ @@ -1816,52 +1854,49 @@ static int run_pipe(struct pipe *pi) return EXIT_SUCCESS; /* don't worry about errors in set_local_var() yet */ } - /* Expand assignments into one string each */ - for (i = 0; i < command->assignment_cnt; i++) { - p = expand_string_to_string(argv[i]); - putenv(p); - ptrs2free = add_malloced_string_to_strings(ptrs2free, p); - } - /* Expand the rest into (possibly) many strings each */ argv_expanded = expand_strvec_to_strvec(argv + i); for (x = bltins; x != &bltins[ARRAY_SIZE(bltins)]; x++) { - if (strcmp(argv_expanded[0], x->cmd) == 0) { - 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); - debug_printf_exec(": builtin '%s' '%s'...\n", x->cmd, argv_expanded[1]); - rcode = x->function(argv_expanded) & 0xff; + 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; USE_FEATURE_SH_STANDALONE(clean_up_and_ret:) - restore_redirects(squirrel); + restore_redirects(squirrel); + free_strings_and_unsetenv(new_env, 1); + putenv_all(old_env); + free_strings(old_env); clean_up_and_ret1: - free_strings_and_unsetenv(ptrs2free, 1); - free(argv_expanded); - IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;) - debug_printf_exec("run_pipe return %d\n", rcode); - return rcode; - } + 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 - { - int a = find_applet_by_name(argv_expanded[0]); - if (a >= 0 && APPLET_IS_NOFORK(a)) { - setup_redirects(command, squirrel); - save_nofork_data(&G.nofork_save); - debug_printf_exec(": run_nofork_applet '%s' '%s'...\n", argv_expanded[0], argv_expanded[1]); - rcode = run_nofork_applet_prime(&G.nofork_save, a, argv_expanded); - goto clean_up_and_ret; - } + 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 } @@ -1883,7 +1918,7 @@ static int run_pipe(struct pipe *pi) /* Avoid confusion WHAT is volatile. Pointer is volatile, * not the stuff it points to. */ typedef char **ppchar_t; - volatile ppchar_t shared_across_vfork; + volatile ppchar_t shared_across_vfork = NULL; #endif command = &(pi->cmds[i]); @@ -1898,9 +1933,6 @@ static int run_pipe(struct pipe *pi) if ((i + 1) < pi->num_cmds) xpipe(pipefds); -#if !BB_MMU - shared_across_vfork = ptrs2free; -#endif command->pid = BB_MMU ? fork() : vfork(); if (!command->pid) { /* child */ if (ENABLE_HUSH_JOB) @@ -1941,12 +1973,11 @@ for single_and_fg, it's already set yes? */ } /* parent */ #if !BB_MMU - ptrs2free = shared_across_vfork; +//BUG: does not restore OLD env var contents + free_strings_and_unsetenv((char **)shared_across_vfork, 1); #endif free(argv_expanded); argv_expanded = NULL; - free_strings_and_unsetenv(ptrs2free, 1); - ptrs2free = NULL; if (command->pid < 0) { /* [v]fork failed */ /* Clearly indicate, was it fork or vfork */ bb_perror_msg(BB_MMU ? "fork" : "vfork"); @@ -3145,7 +3176,7 @@ static int done_word(o_string *word, struct parse_context *ctx) o_addchr(word, SPECIAL_VAR_SYMBOL); } } - command->argv = add_malloced_string_to_strings(command->argv, xstrdup(word->data)); + command->argv = add_string_to_strings(command->argv, xstrdup(word->data)); debug_print_strings("word appended to argv", command->argv); } @@ -3436,6 +3467,11 @@ static int parse_group(o_string *dest, struct parse_context *ctx, endch = ")"; command->subshell = 1; } +#if 0 /* TODO function support */ + if (ch == 'F') { /* function definition */ + command->subshell = 2; + } +#endif rcode = parse_stream(dest, &sub, input, endch); if (rcode == 0) { done_word(dest, &sub); /* finish off the final word in the subcontext */ @@ -3929,10 +3965,10 @@ static int parse_stream(o_string *dest, struct parse_context *ctx, case '(': #if ENABLE_HUSH_CASE /* "case... in [(]word)..." - skip '(' */ - if (dest->length == 0 /* not word(... */ - && dest->nonnull == 0 /* not ""(... */ - && ctx->ctx_res_w == RES_MATCH + if (ctx->ctx_res_w == RES_MATCH && ctx->command->argv == NULL /* not (word|(... */ + && dest->length == 0 /* not word(... */ + && dest->nonnull == 0 /* not ""(... */ ) { continue; } @@ -3942,10 +3978,18 @@ static int parse_stream(o_string *dest, struct parse_context *ctx, && dest->nonnull == 0 /* not a"b"c() */ && ctx->command->argv == NULL /* it's the first word */ && i_peek(input) == ')' + && !match_reserved_word(dest) ) { bb_error_msg("seems like a function definition"); - if (match_reserved_word(dest)) - bb_error_msg("but '%s' is a reserved word!", dest->data); + i_getch(input); + do { + ch = i_getch(input); + } while (ch == ' ' || ch == '\n'); + if (ch != '{') { + syntax("was expecting {"); + debug_printf_parse("parse_stream return 1\n"); + return 1; + } } #endif case '{': -- cgit v1.2.3