diff options
Diffstat (limited to 'shell')
-rw-r--r-- | shell/hush.c | 104 | ||||
-rw-r--r-- | shell/hush_test/hush-trap/subshell.right | 15 | ||||
-rwxr-xr-x | shell/hush_test/hush-trap/subshell.tests | 10 |
3 files changed, 88 insertions, 41 deletions
diff --git a/shell/hush.c b/shell/hush.c index 7d851ed..8de8d3c 100644 --- a/shell/hush.c +++ b/shell/hush.c @@ -520,6 +520,7 @@ struct globals { smalluint last_exitcode; /* are global_argv and global_argv[1..n] malloced? (note: not [0]) */ smalluint global_args_malloced; + smalluint inherited_set_is_saved; /* how many non-NULL argv's we have. NB: $# + 1 */ int global_argc; char **global_argv; @@ -1050,7 +1051,8 @@ static void restore_G_args(save_arg_t *sv, char **argv) * * Trap handlers will execute even within trap handlers. (right?) * - * User trap handlers are forgotten when subshell ("(cmd)") is entered. + * User trap handlers are forgotten when subshell ("(cmd)") is entered, + * except for handlers set to '' (empty string). * * If job control is off, backgrounded commands ("cmd &") * have SIGINT, SIGQUIT set to SIG_IGN. @@ -1106,7 +1108,7 @@ static void restore_G_args(save_arg_t *sv, char **argv) * after [v]fork, if we plan to be a shell: * unblock signals with special interactive handling * (child shell is not interactive), - * unset all traps (note: regardless of child shell's type - {}, (), etc) + * unset all traps except '' (note: regardless of child shell's type - {}, (), etc) * after [v]fork, if we plan to exec: * POSIX says fork clears pending signal mask in child - no need to clear it. * Restore blocked signal set to one inherited by shell just prior to exec. @@ -1118,7 +1120,7 @@ static void restore_G_args(save_arg_t *sv, char **argv) * Note 2 (compat): * Standard says "When a subshell is entered, traps that are not being ignored * are set to the default actions". bash interprets it so that traps which - * are set to "" (ignore) are NOT reset to defaults. We do the same. + * are set to '' (ignore) are NOT reset to defaults. We do the same. */ enum { SPECIAL_INTERACTIVE_SIGS = 0 @@ -2925,6 +2927,7 @@ static void re_execute_shell(char ***to_free, const char *s, # endif char **argv, **pp; unsigned cnt; + unsigned long long empty_trap_mask; if (!g_argv0) { /* heredoc */ argv = heredoc_argv; @@ -2941,12 +2944,22 @@ static void re_execute_shell(char ***to_free, const char *s, if (pp) while (*pp++) cnt++; - sprintf(param_buf, "-$%x:%x:%x:%x:%x" IF_HUSH_LOOPS(":%x") + empty_trap_mask = 0; + if (G.traps) { + int sig; + for (sig = 1; sig < NSIG; sig++) { + if (G.traps[sig] && !G.traps[sig][0]) + empty_trap_mask |= 1LL << sig; + } + } + + sprintf(param_buf, "-$%x:%x:%x:%x:%x:%llx" IF_HUSH_LOOPS(":%x") , (unsigned) G.root_pid , (unsigned) G.root_ppid , (unsigned) G.last_bg_pid , (unsigned) G.last_exitcode , cnt + , empty_trap_mask IF_HUSH_LOOPS(, G.depth_of_loop) ); /* 1:hush 2:-$<pid>:<pid>:<exitcode>:<depth> <vars...> <funcs...> @@ -3002,7 +3015,9 @@ static void re_execute_shell(char ***to_free, const char *s, * _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. + * Even if we would use signal handlers instead of signal masking + * in order to implement trap handling, + * exec syscall below resets signals to SIG_DFL for us. */ *pp++ = (char *) "-c"; *pp++ = (char *) s; @@ -5447,7 +5462,7 @@ static FILE *generate_stream_from_string(const char *s, pid_t *pid_p) pid_t pid; int channel[2]; # if !BB_MMU - char **to_free; + char **to_free = NULL; # endif xpipe(channel); @@ -6677,10 +6692,17 @@ static void parse_and_run_file(FILE *f) } /* Called a few times only (or even once if "sh -c") */ -static void block_signals(int second_time) +static void init_sigmasks(void) { unsigned sig; unsigned mask; + sigset_t old_blocked_set; + + if (!G.inherited_set_is_saved) { + sigprocmask(SIG_SETMASK, NULL, &G.blocked_set); + G.inherited_set = G.blocked_set; + } + old_blocked_set = G.blocked_set; mask = (1 << SIGQUIT); if (G_interactive_fd) { @@ -6690,8 +6712,6 @@ static void block_signals(int second_time) } G.non_DFL_mask = mask; - if (!second_time) - sigprocmask(SIG_SETMASK, NULL, &G.blocked_set); sig = 0; while (mask) { if (mask & 1) @@ -6701,18 +6721,21 @@ static void block_signals(int second_time) } sigdelset(&G.blocked_set, SIGCHLD); - sigprocmask(SIG_SETMASK, &G.blocked_set, - second_time ? NULL : &G.inherited_set); + if (memcmp(&old_blocked_set, &G.blocked_set, sizeof(old_blocked_set)) != 0) + sigprocmask(SIG_SETMASK, &G.blocked_set, NULL); + /* POSIX allows shell to re-enable SIGCHLD * even if it was SIG_IGN on entry */ #if ENABLE_HUSH_FAST G.count_SIGCHLD++; /* ensure it is != G.handled_SIGCHLD */ - if (!second_time) + if (!G.inherited_set_is_saved) signal(SIGCHLD, SIGCHLD_handler); #else - if (!second_time) + if (!G.inherited_set_is_saved) signal(SIGCHLD, SIG_DFL); #endif + + G.inherited_set_is_saved = 1; } #if ENABLE_HUSH_JOB @@ -6774,7 +6797,6 @@ int hush_main(int argc, char **argv) .flg_export = 1, .flg_read_only = 1, }; - int signal_mask_is_inited = 0; int opt; unsigned builtin_argc; char **e; @@ -6865,10 +6887,9 @@ int hush_main(int argc, char **argv) } /* Shell is non-interactive at first. We need to call - * block_signals(0) if we are going to execute "sh <script>", + * init_sigmasks() if we are going to execute "sh <script>", * "sh -c <cmds>" or login shell's /etc/profile and friends. - * If we later decide that we are interactive, we run block_signals(0) - * (or re-run block_signals(1) if we ran block_signals(0) before) + * If we later decide that we are interactive, we run init_sigmasks() * in order to intercept (more) signals. */ @@ -6908,7 +6929,7 @@ int hush_main(int argc, char **argv) /* -c 'builtin' [BARGV...] "" ARG0 [ARG1...] */ const struct built_in_command *x; - block_signals(0); /* 0: called 1st time */ + init_sigmasks(); x = find_builtin(optarg); if (x) { /* paranoia */ G.global_argc -= builtin_argc; /* skip [BARGV...] "" */ @@ -6924,7 +6945,7 @@ int hush_main(int argc, char **argv) G.global_argv[0] = argv[0]; G.global_argc--; } /* else -c 'script' ARG0 [ARG1...]: $0 is ARG0 */ - block_signals(0); /* 0: called 1st time */ + init_sigmasks(); parse_and_run_string(optarg); goto final_return; case 'i': @@ -6940,7 +6961,9 @@ int hush_main(int argc, char **argv) case '<': /* "big heredoc" support */ full_write(STDOUT_FILENO, optarg, strlen(optarg)); _exit(0); - case '$': + case '$': { + unsigned long long empty_trap_mask; + G.root_pid = bb_strtou(optarg, &optarg, 16); optarg++; G.root_ppid = bb_strtou(optarg, &optarg, 16); @@ -6950,11 +6973,26 @@ int hush_main(int argc, char **argv) G.last_exitcode = bb_strtou(optarg, &optarg, 16); optarg++; builtin_argc = bb_strtou(optarg, &optarg, 16); + optarg++; + empty_trap_mask = bb_strtoull(optarg, &optarg, 16); + if (empty_trap_mask != 0) { + int sig; + init_sigmasks(); + G.traps = xzalloc(sizeof(G.traps[0]) * NSIG); + for (sig = 1; sig < NSIG; sig++) { + if (empty_trap_mask & (1LL << sig)) { + G.traps[sig] = xzalloc(1); /* == xstrdup(""); */ + sigaddset(&G.blocked_set, sig); + } + } + sigprocmask(SIG_SETMASK, &G.blocked_set, NULL); + } # if ENABLE_HUSH_LOOPS optarg++; G.depth_of_loop = bb_strtou(optarg, &optarg, 16); # endif break; + } case 'R': case 'V': set_local_var(xstrdup(optarg), /*exp:*/ 0, /*lvl:*/ 0, /*ro:*/ opt == 'R'); @@ -6997,8 +7035,7 @@ int hush_main(int argc, char **argv) input = fopen_for_read("/etc/profile"); if (input != NULL) { close_on_exec_on(fileno(input)); - block_signals(0); /* 0: called 1st time */ - signal_mask_is_inited = 1; + init_sigmasks(); parse_and_run_file(input); fclose(input); } @@ -7023,8 +7060,7 @@ int hush_main(int argc, char **argv) G.global_argc = argc - optind; input = xfopen_for_read(argv[optind]); close_on_exec_on(fileno(input)); - if (!signal_mask_is_inited) - block_signals(0); /* 0: called 1st time */ + init_sigmasks(); parse_and_run_file(input); #if ENABLE_FEATURE_CLEAN_UP fclose(input); @@ -7033,7 +7069,7 @@ int hush_main(int argc, char **argv) } /* Up to here, shell was non-interactive. Now it may become one. - * NB: don't forget to (re)run block_signals(0/1) as needed. + * NB: don't forget to (re)run init_sigmasks() as needed. */ /* A shell is interactive if the '-i' flag was given, @@ -7086,7 +7122,7 @@ int hush_main(int argc, char **argv) } /* Block some signals */ - block_signals(signal_mask_is_inited); + init_sigmasks(); if (G_saved_tty_pgrp) { /* Set other signals to restore saved_tty_pgrp */ @@ -7100,9 +7136,9 @@ int hush_main(int argc, char **argv) /* -1 is special - makes xfuncs longjmp, not exit * (we reset die_sleep = 0 whereever we [v]fork) */ enable_restore_tty_pgrp_on_exit(); /* sets die_sleep = -1 */ - } else if (!signal_mask_is_inited) { - block_signals(0); /* 0: called 1st time */ - } /* else: block_signals(0) was done before */ + } else { + init_sigmasks(); + } #elif ENABLE_HUSH_INTERACTIVE /* No job control compiled in, only prompt/line editing */ if (isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) { @@ -7117,15 +7153,11 @@ int hush_main(int argc, char **argv) } if (G_interactive_fd) { close_on_exec_on(G_interactive_fd); - block_signals(signal_mask_is_inited); - } else if (!signal_mask_is_inited) { - block_signals(0); } + init_sigmasks(); #else /* We have interactiveness code disabled */ - if (!signal_mask_is_inited) { - block_signals(0); - } + init_sigmasks(); #endif /* bash: * if interactive but not a login shell, sources ~/.bashrc @@ -7471,7 +7503,7 @@ static int FAST_FUNC builtin_trap(char **argv) free(G.traps[sig]); G.traps[sig] = xstrdup(new_cmd); - debug_printf("trap: setting SIG%s (%i) to '%s'", + debug_printf("trap: setting SIG%s (%i) to '%s'\n", get_signame(sig), sig, G.traps[sig]); /* There is no signal for 0 (EXIT) */ diff --git a/shell/hush_test/hush-trap/subshell.right b/shell/hush_test/hush-trap/subshell.right index 0d20ed4..f865b93 100644 --- a/shell/hush_test/hush-trap/subshell.right +++ b/shell/hush_test/hush-trap/subshell.right @@ -1,6 +1,21 @@ +trap -- '' HUP +trap -- '' QUIT +trap -- '' SYS Ok +trap -- '' HUP +trap -- '' QUIT +trap -- '' SYS Ok +trap -- '' HUP +trap -- '' QUIT +trap -- '' SYS Ok +trap -- '' HUP +trap -- '' QUIT +trap -- '' SYS Ok +trap -- '' HUP +trap -- '' QUIT +trap -- '' SYS TERM Done diff --git a/shell/hush_test/hush-trap/subshell.tests b/shell/hush_test/hush-trap/subshell.tests index 4564c2e..045294b 100755 --- a/shell/hush_test/hush-trap/subshell.tests +++ b/shell/hush_test/hush-trap/subshell.tests @@ -12,9 +12,9 @@ trap 'bad: caught WINCH' WINCH trap 'bad: caught TERM' TERM # using bash, because we don't have $PPID (yet) -(bash -c 'kill -HUP $PPID'; echo Ok) -(bash -c 'kill -QUIT $PPID'; echo Ok) -(bash -c 'kill -SYS $PPID'; echo Ok) -(bash -c 'kill -WINCH $PPID'; echo Ok) -(bash -c 'kill -TERM $PPID'; echo Bad: TERM is not reset) +(trap; bash -c 'kill -HUP $PPID'; echo Ok) +(trap; bash -c 'kill -QUIT $PPID'; echo Ok) +(trap; bash -c 'kill -SYS $PPID'; echo Ok) +(trap; bash -c 'kill -WINCH $PPID'; echo Ok) +(trap; bash -c 'kill -TERM $PPID'; echo Bad: TERM is not reset) echo Done |