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Diffstat (limited to 'trap.c')
| -rw-r--r-- | trap.c | 1065 |
1 files changed, 1065 insertions, 0 deletions
@@ -0,0 +1,1065 @@ +/* trap.c -- Not the trap command, but useful functions for manipulating + those objects. The trap command is in builtins/trap.def. */ + +/* Copyright (C) 1987-2009 Free Software Foundation, Inc. + + This file is part of GNU Bash, the Bourne Again SHell. + + Bash 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 3 of the License, or + (at your option) any later version. + + Bash 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 Bash. If not, see <http://www.gnu.org/licenses/>. +*/ + +#include "config.h" + +#if defined (HAVE_UNISTD_H) +# include <unistd.h> +#endif + +#include "bashtypes.h" +#include "bashansi.h" + +#include <stdio.h> +#include <errno.h> + +#include "bashintl.h" + +#include "trap.h" + +#include "shell.h" +#include "flags.h" +#include "input.h" /* for save_token_state, restore_token_state */ +#include "jobs.h" +#include "signames.h" +#include "builtins.h" +#include "builtins/common.h" +#include "builtins/builtext.h" + +#ifndef errno +extern int errno; +#endif + +/* Flags which describe the current handling state of a signal. */ +#define SIG_INHERITED 0x0 /* Value inherited from parent. */ +#define SIG_TRAPPED 0x1 /* Currently trapped. */ +#define SIG_HARD_IGNORE 0x2 /* Signal was ignored on shell entry. */ +#define SIG_SPECIAL 0x4 /* Treat this signal specially. */ +#define SIG_NO_TRAP 0x8 /* Signal cannot be trapped. */ +#define SIG_INPROGRESS 0x10 /* Signal handler currently executing. */ +#define SIG_CHANGED 0x20 /* Trap value changed in trap handler. */ +#define SIG_IGNORED 0x40 /* The signal is currently being ignored. */ + +#define SPECIAL_TRAP(s) ((s) == EXIT_TRAP || (s) == DEBUG_TRAP || (s) == ERROR_TRAP || (s) == RETURN_TRAP) + +/* An array of such flags, one for each signal, describing what the + shell will do with a signal. DEBUG_TRAP == NSIG; some code below + assumes this. */ +static int sigmodes[BASH_NSIG]; + +static void free_trap_command __P((int)); +static void change_signal __P((int, char *)); + +static void get_original_signal __P((int)); + +static int _run_trap_internal __P((int, char *)); + +static void free_trap_string __P((int)); +static void reset_signal __P((int)); +static void restore_signal __P((int)); +static void reset_or_restore_signal_handlers __P((sh_resetsig_func_t *)); + +/* Variables used here but defined in other files. */ +extern int last_command_exit_value; +extern int line_number; + +extern char *this_command_name; +extern sh_builtin_func_t *this_shell_builtin; +extern procenv_t wait_intr_buf; +extern int return_catch_flag, return_catch_value; +extern int subshell_level; +extern WORD_LIST *subst_assign_varlist; + +/* The list of things to do originally, before we started trapping. */ +SigHandler *original_signals[NSIG]; + +/* For each signal, a slot for a string, which is a command to be + executed when that signal is recieved. The slot can also contain + DEFAULT_SIG, which means do whatever you were going to do before + you were so rudely interrupted, or IGNORE_SIG, which says ignore + this signal. */ +char *trap_list[BASH_NSIG]; + +/* A bitmap of signals received for which we have trap handlers. */ +int pending_traps[NSIG]; + +/* Set to the number of the signal we're running the trap for + 1. + Used in execute_cmd.c and builtins/common.c to clean up when + parse_and_execute does not return normally after executing the + trap command (e.g., when `return' is executed in the trap command). */ +int running_trap; + +/* Set to last_command_exit_value before running a trap. */ +int trap_saved_exit_value; + +/* The (trapped) signal received while executing in the `wait' builtin */ +int wait_signal_received; + +/* A value which can never be the target of a trap handler. */ +#define IMPOSSIBLE_TRAP_HANDLER (SigHandler *)initialize_traps + +#define GETORIGSIG(sig) \ + do { \ + original_signals[sig] = (SigHandler *)set_signal_handler (sig, SIG_DFL); \ + set_signal_handler (sig, original_signals[sig]); \ + if (original_signals[sig] == SIG_IGN) \ + sigmodes[sig] |= SIG_HARD_IGNORE; \ + } while (0) + +#define GET_ORIGINAL_SIGNAL(sig) \ + if (sig && sig < NSIG && original_signals[sig] == IMPOSSIBLE_TRAP_HANDLER) \ + GETORIGSIG(sig) + +void +initialize_traps () +{ + register int i; + + initialize_signames(); + + trap_list[EXIT_TRAP] = trap_list[DEBUG_TRAP] = trap_list[ERROR_TRAP] = trap_list[RETURN_TRAP] = (char *)NULL; + sigmodes[EXIT_TRAP] = sigmodes[DEBUG_TRAP] = sigmodes[ERROR_TRAP] = sigmodes[RETURN_TRAP] = SIG_INHERITED; + original_signals[EXIT_TRAP] = IMPOSSIBLE_TRAP_HANDLER; + + for (i = 1; i < NSIG; i++) + { + pending_traps[i] = 0; + trap_list[i] = (char *)DEFAULT_SIG; + sigmodes[i] = SIG_INHERITED; + original_signals[i] = IMPOSSIBLE_TRAP_HANDLER; + } + + /* Show which signals are treated specially by the shell. */ +#if defined (SIGCHLD) + GETORIGSIG (SIGCHLD); + sigmodes[SIGCHLD] |= (SIG_SPECIAL | SIG_NO_TRAP); +#endif /* SIGCHLD */ + + GETORIGSIG (SIGINT); + sigmodes[SIGINT] |= SIG_SPECIAL; + +#if defined (__BEOS__) + /* BeOS sets SIGINT to SIG_IGN! */ + original_signals[SIGINT] = SIG_DFL; + sigmodes[SIGINT] &= ~SIG_HARD_IGNORE; +#endif + + GETORIGSIG (SIGQUIT); + sigmodes[SIGQUIT] |= SIG_SPECIAL; + + if (interactive) + { + GETORIGSIG (SIGTERM); + sigmodes[SIGTERM] |= SIG_SPECIAL; + } +} + +#ifdef INCLUDE_UNUSED +/* Return a printable representation of the trap handler for SIG. */ +static char * +trap_handler_string (sig) + int sig; +{ + if (trap_list[sig] == (char *)DEFAULT_SIG) + return "DEFAULT_SIG"; + else if (trap_list[sig] == (char *)IGNORE_SIG) + return "IGNORE_SIG"; + else if (trap_list[sig] == (char *)IMPOSSIBLE_TRAP_HANDLER) + return "IMPOSSIBLE_TRAP_HANDLER"; + else if (trap_list[sig]) + return trap_list[sig]; + else + return "NULL"; +} +#endif + +/* Return the print name of this signal. */ +char * +signal_name (sig) + int sig; +{ + char *ret; + + /* on cygwin32, signal_names[sig] could be null */ + ret = (sig >= BASH_NSIG || sig < 0 || signal_names[sig] == NULL) + ? _("invalid signal number") + : signal_names[sig]; + + return ret; +} + +/* Turn a string into a signal number, or a number into + a signal number. If STRING is "2", "SIGINT", or "INT", + then (int)2 is returned. Return NO_SIG if STRING doesn't + contain a valid signal descriptor. */ +int +decode_signal (string, flags) + char *string; + int flags; +{ + intmax_t sig; + char *name; + + if (legal_number (string, &sig)) + return ((sig >= 0 && sig < NSIG) ? (int)sig : NO_SIG); + + /* A leading `SIG' may be omitted. */ + for (sig = 0; sig < BASH_NSIG; sig++) + { + name = signal_names[sig]; + if (name == 0 || name[0] == '\0') + continue; + + /* Check name without the SIG prefix first case sensitivly or + insensitively depending on whether flags includes DSIG_NOCASE */ + if (STREQN (name, "SIG", 3)) + { + name += 3; + + if ((flags & DSIG_NOCASE) && strcasecmp (string, name) == 0) + return ((int)sig); + else if ((flags & DSIG_NOCASE) == 0 && strcmp (string, name) == 0) + return ((int)sig); + /* If we can't use the `SIG' prefix to match, punt on this + name now. */ + else if ((flags & DSIG_SIGPREFIX) == 0) + continue; + } + + /* Check name with SIG prefix case sensitively or insensitively + depending on whether flags includes DSIG_NOCASE */ + name = signal_names[sig]; + if ((flags & DSIG_NOCASE) && strcasecmp (string, name) == 0) + return ((int)sig); + else if ((flags & DSIG_NOCASE) == 0 && strcmp (string, name) == 0) + return ((int)sig); + } + + return (NO_SIG); +} + +/* Non-zero when we catch a trapped signal. */ +static int catch_flag; + +void +run_pending_traps () +{ + register int sig; + int old_exit_value, *token_state; + WORD_LIST *save_subst_varlist; + + if (catch_flag == 0) /* simple optimization */ + return; + + catch_flag = 0; + + /* Preserve $? when running trap. */ + old_exit_value = last_command_exit_value; + + for (sig = 1; sig < NSIG; sig++) + { + /* XXX this could be made into a counter by using + while (pending_traps[sig]--) instead of the if statement. */ + if (pending_traps[sig]) + { +#if defined (HAVE_POSIX_SIGNALS) + sigset_t set, oset; + + sigemptyset (&set); + sigemptyset (&oset); + + sigaddset (&set, sig); + sigprocmask (SIG_BLOCK, &set, &oset); +#else +# if defined (HAVE_BSD_SIGNALS) + int oldmask = sigblock (sigmask (sig)); +# endif +#endif /* HAVE_POSIX_SIGNALS */ + + if (sig == SIGINT) + { + run_interrupt_trap (); + CLRINTERRUPT; + } +#if defined (JOB_CONTROL) && defined (SIGCHLD) + else if (sig == SIGCHLD && + trap_list[SIGCHLD] != (char *)IMPOSSIBLE_TRAP_HANDLER && + (sigmodes[SIGCHLD] & SIG_INPROGRESS) == 0) + { + run_sigchld_trap (pending_traps[sig]); /* use as counter */ + } +#endif + else if (trap_list[sig] == (char *)DEFAULT_SIG || + trap_list[sig] == (char *)IGNORE_SIG || + trap_list[sig] == (char *)IMPOSSIBLE_TRAP_HANDLER) + { + /* This is possible due to a race condition. Say a bash + process has SIGTERM trapped. A subshell is spawned + using { list; } & and the parent does something and kills + the subshell with SIGTERM. It's possible for the subshell + to set pending_traps[SIGTERM] to 1 before the code in + execute_cmd.c eventually calls restore_original_signals + to reset the SIGTERM signal handler in the subshell. The + next time run_pending_traps is called, pending_traps[SIGTERM] + will be 1, but the trap handler in trap_list[SIGTERM] will + be invalid (probably DEFAULT_SIG, but it could be IGNORE_SIG). + Unless we catch this, the subshell will dump core when + trap_list[SIGTERM] == DEFAULT_SIG, because DEFAULT_SIG is + usually 0x0. */ + internal_warning (_("run_pending_traps: bad value in trap_list[%d]: %p"), + sig, trap_list[sig]); + if (trap_list[sig] == (char *)DEFAULT_SIG) + { + internal_warning (_("run_pending_traps: signal handler is SIG_DFL, resending %d (%s) to myself"), sig, signal_name (sig)); + kill (getpid (), sig); + } + } + else + { + token_state = save_token_state (); + save_subst_varlist = subst_assign_varlist; + subst_assign_varlist = 0; + + parse_and_execute (savestring (trap_list[sig]), "trap", SEVAL_NONINT|SEVAL_NOHIST|SEVAL_RESETLINE); + restore_token_state (token_state); + free (token_state); + + subst_assign_varlist = save_subst_varlist; + } + + pending_traps[sig] = 0; + +#if defined (HAVE_POSIX_SIGNALS) + sigprocmask (SIG_SETMASK, &oset, (sigset_t *)NULL); +#else +# if defined (HAVE_BSD_SIGNALS) + sigsetmask (oldmask); +# endif +#endif /* POSIX_VERSION */ + } + } + + last_command_exit_value = old_exit_value; +} + +sighandler +trap_handler (sig) + int sig; +{ + int oerrno; + + if ((sigmodes[sig] & SIG_TRAPPED) == 0) + { +#if defined (DEBUG) + internal_warning ("trap_handler: signal %d: signal not trapped", sig); +#endif + SIGRETURN (0); + } + + if ((sig >= NSIG) || + (trap_list[sig] == (char *)DEFAULT_SIG) || + (trap_list[sig] == (char *)IGNORE_SIG)) + programming_error (_("trap_handler: bad signal %d"), sig); + else + { + oerrno = errno; +#if defined (MUST_REINSTALL_SIGHANDLERS) +# if defined (JOB_CONTROL) && defined (SIGCHLD) + if (sig != SIGCHLD) +# endif /* JOB_CONTROL && SIGCHLD */ + set_signal_handler (sig, trap_handler); +#endif /* MUST_REINSTALL_SIGHANDLERS */ + + catch_flag = 1; + pending_traps[sig]++; + + if (interrupt_immediately && this_shell_builtin && (this_shell_builtin == wait_builtin)) + { + wait_signal_received = sig; + longjmp (wait_intr_buf, 1); + } + + if (interrupt_immediately) + run_pending_traps (); + + errno = oerrno; + } + + SIGRETURN (0); +} + +#if defined (JOB_CONTROL) && defined (SIGCHLD) + +#ifdef INCLUDE_UNUSED +/* Make COMMAND_STRING be executed when SIGCHLD is caught. */ +void +set_sigchld_trap (command_string) + char *command_string; +{ + set_signal (SIGCHLD, command_string); +} +#endif + +/* Make COMMAND_STRING be executed when SIGCHLD is caught iff SIGCHLD + is not already trapped. IMPOSSIBLE_TRAP_HANDLER is used as a sentinel + to make sure that a SIGCHLD trap handler run via run_sigchld_trap can + reset the disposition to the default and not have the original signal + accidentally restored, undoing the user's command. */ +void +maybe_set_sigchld_trap (command_string) + char *command_string; +{ + if ((sigmodes[SIGCHLD] & SIG_TRAPPED) == 0 && trap_list[SIGCHLD] == (char *)IMPOSSIBLE_TRAP_HANDLER) + set_signal (SIGCHLD, command_string); +} + +/* Temporarily set the SIGCHLD trap string to IMPOSSIBLE_TRAP_HANDLER. Used + as a sentinel in run_sigchld_trap and maybe_set_sigchld_trap to see whether + or not a SIGCHLD trap handler reset SIGCHLD disposition to the default. */ +void +set_impossible_sigchld_trap () +{ + restore_default_signal (SIGCHLD); + change_signal (SIGCHLD, (char *)IMPOSSIBLE_TRAP_HANDLER); + sigmodes[SIGCHLD] &= ~SIG_TRAPPED; /* maybe_set_sigchld_trap checks this */ +} +#endif /* JOB_CONTROL && SIGCHLD */ + +void +set_debug_trap (command) + char *command; +{ + set_signal (DEBUG_TRAP, command); +} + +void +set_error_trap (command) + char *command; +{ + set_signal (ERROR_TRAP, command); +} + +void +set_return_trap (command) + char *command; +{ + set_signal (RETURN_TRAP, command); +} + +#ifdef INCLUDE_UNUSED +void +set_sigint_trap (command) + char *command; +{ + set_signal (SIGINT, command); +} +#endif + +/* Reset the SIGINT handler so that subshells that are doing `shellsy' + things, like waiting for command substitution or executing commands + in explicit subshells ( ( cmd ) ), can catch interrupts properly. */ +SigHandler * +set_sigint_handler () +{ + if (sigmodes[SIGINT] & SIG_HARD_IGNORE) + return ((SigHandler *)SIG_IGN); + + else if (sigmodes[SIGINT] & SIG_IGNORED) + return ((SigHandler *)set_signal_handler (SIGINT, SIG_IGN)); /* XXX */ + + else if (sigmodes[SIGINT] & SIG_TRAPPED) + return ((SigHandler *)set_signal_handler (SIGINT, trap_handler)); + + /* The signal is not trapped, so set the handler to the shell's special + interrupt handler. */ + else if (interactive) /* XXX - was interactive_shell */ + return (set_signal_handler (SIGINT, sigint_sighandler)); + else + return (set_signal_handler (SIGINT, termsig_sighandler)); +} + +/* Return the correct handler for signal SIG according to the values in + sigmodes[SIG]. */ +SigHandler * +trap_to_sighandler (sig) + int sig; +{ + if (sigmodes[sig] & (SIG_IGNORED|SIG_HARD_IGNORE)) + return (SIG_IGN); + else if (sigmodes[sig] & SIG_TRAPPED) + return (trap_handler); + else + return (SIG_DFL); +} + +/* Set SIG to call STRING as a command. */ +void +set_signal (sig, string) + int sig; + char *string; +{ + if (SPECIAL_TRAP (sig)) + { + change_signal (sig, savestring (string)); + if (sig == EXIT_TRAP && interactive == 0) + initialize_terminating_signals (); + return; + } + + /* A signal ignored on entry to the shell cannot be trapped or reset, but + no error is reported when attempting to do so. -- Posix.2 */ + if (sigmodes[sig] & SIG_HARD_IGNORE) + return; + + /* Make sure we have original_signals[sig] if the signal has not yet + been trapped. */ + if ((sigmodes[sig] & SIG_TRAPPED) == 0) + { + /* If we aren't sure of the original value, check it. */ + if (original_signals[sig] == IMPOSSIBLE_TRAP_HANDLER) + GETORIGSIG (sig); + if (original_signals[sig] == SIG_IGN) + return; + } + + /* Only change the system signal handler if SIG_NO_TRAP is not set. + The trap command string is changed in either case. The shell signal + handlers for SIGINT and SIGCHLD run the user specified traps in an + environment in which it is safe to do so. */ + if ((sigmodes[sig] & SIG_NO_TRAP) == 0) + { + set_signal_handler (sig, SIG_IGN); + change_signal (sig, savestring (string)); + set_signal_handler (sig, trap_handler); + } + else + change_signal (sig, savestring (string)); +} + +static void +free_trap_command (sig) + int sig; +{ + if ((sigmodes[sig] & SIG_TRAPPED) && trap_list[sig] && + (trap_list[sig] != (char *)IGNORE_SIG) && + (trap_list[sig] != (char *)DEFAULT_SIG) && + (trap_list[sig] != (char *)IMPOSSIBLE_TRAP_HANDLER)) + free (trap_list[sig]); +} + +/* If SIG has a string assigned to it, get rid of it. Then give it + VALUE. */ +static void +change_signal (sig, value) + int sig; + char *value; +{ + if ((sigmodes[sig] & SIG_INPROGRESS) == 0) + free_trap_command (sig); + trap_list[sig] = value; + + sigmodes[sig] |= SIG_TRAPPED; + if (value == (char *)IGNORE_SIG) + sigmodes[sig] |= SIG_IGNORED; + else + sigmodes[sig] &= ~SIG_IGNORED; + if (sigmodes[sig] & SIG_INPROGRESS) + sigmodes[sig] |= SIG_CHANGED; +} + +static void +get_original_signal (sig) + int sig; +{ + /* If we aren't sure the of the original value, then get it. */ + if (sig > 0 && sig < NSIG && original_signals[sig] == (SigHandler *)IMPOSSIBLE_TRAP_HANDLER) + GETORIGSIG (sig); +} + +/* Restore the default action for SIG; i.e., the action the shell + would have taken before you used the trap command. This is called + from trap_builtin (), which takes care to restore the handlers for + the signals the shell treats specially. */ +void +restore_default_signal (sig) + int sig; +{ + if (SPECIAL_TRAP (sig)) + { + if ((sig != DEBUG_TRAP && sig != ERROR_TRAP && sig != RETURN_TRAP) || + (sigmodes[sig] & SIG_INPROGRESS) == 0) + free_trap_command (sig); + trap_list[sig] = (char *)NULL; + sigmodes[sig] &= ~SIG_TRAPPED; + if (sigmodes[sig] & SIG_INPROGRESS) + sigmodes[sig] |= SIG_CHANGED; + return; + } + + GET_ORIGINAL_SIGNAL (sig); + + /* A signal ignored on entry to the shell cannot be trapped or reset, but + no error is reported when attempting to do so. Thanks Posix.2. */ + if (sigmodes[sig] & SIG_HARD_IGNORE) + return; + + /* If we aren't trapping this signal, don't bother doing anything else. */ + if ((sigmodes[sig] & SIG_TRAPPED) == 0) + return; + + /* Only change the signal handler for SIG if it allows it. */ + if ((sigmodes[sig] & SIG_NO_TRAP) == 0) + set_signal_handler (sig, original_signals[sig]); + + /* Change the trap command in either case. */ + change_signal (sig, (char *)DEFAULT_SIG); + + /* Mark the signal as no longer trapped. */ + sigmodes[sig] &= ~SIG_TRAPPED; +} + +/* Make this signal be ignored. */ +void +ignore_signal (sig) + int sig; +{ + if (SPECIAL_TRAP (sig) && ((sigmodes[sig] & SIG_IGNORED) == 0)) + { + change_signal (sig, (char *)IGNORE_SIG); + return; + } + + GET_ORIGINAL_SIGNAL (sig); + + /* A signal ignored on entry to the shell cannot be trapped or reset. + No error is reported when the user attempts to do so. */ + if (sigmodes[sig] & SIG_HARD_IGNORE) + return; + + /* If already trapped and ignored, no change necessary. */ + if (sigmodes[sig] & SIG_IGNORED) + return; + + /* Only change the signal handler for SIG if it allows it. */ + if ((sigmodes[sig] & SIG_NO_TRAP) == 0) + set_signal_handler (sig, SIG_IGN); + + /* Change the trap command in either case. */ + change_signal (sig, (char *)IGNORE_SIG); +} + +/* Handle the calling of "trap 0". The only sticky situation is when + the command to be executed includes an "exit". This is why we have + to provide our own place for top_level to jump to. */ +int +run_exit_trap () +{ + char *trap_command; + int code, function_code, retval; + + trap_saved_exit_value = last_command_exit_value; + function_code = 0; + + /* Run the trap only if signal 0 is trapped and not ignored, and we are not + currently running in the trap handler (call to exit in the list of + commands given to trap 0). */ + if ((sigmodes[EXIT_TRAP] & SIG_TRAPPED) && + (sigmodes[EXIT_TRAP] & (SIG_IGNORED|SIG_INPROGRESS)) == 0) + { + trap_command = savestring (trap_list[EXIT_TRAP]); + sigmodes[EXIT_TRAP] &= ~SIG_TRAPPED; + sigmodes[EXIT_TRAP] |= SIG_INPROGRESS; + + retval = trap_saved_exit_value; + running_trap = 1; + + code = setjmp (top_level); + + /* If we're in a function, make sure return longjmps come here, too. */ + if (return_catch_flag) + function_code = setjmp (return_catch); + + if (code == 0 && function_code == 0) + { + reset_parser (); + parse_and_execute (trap_command, "exit trap", SEVAL_NONINT|SEVAL_NOHIST|SEVAL_RESETLINE); + } + else if (code == ERREXIT) + retval = last_command_exit_value; + else if (code == EXITPROG) + retval = last_command_exit_value; + else if (function_code != 0) + retval = return_catch_value; + else + retval = trap_saved_exit_value; + + running_trap = 0; + return retval; + } + + return (trap_saved_exit_value); +} + +void +run_trap_cleanup (sig) + int sig; +{ + sigmodes[sig] &= ~(SIG_INPROGRESS|SIG_CHANGED); +} + +/* Run a trap command for SIG. SIG is one of the signals the shell treats + specially. Returns the exit status of the executed trap command list. */ +static int +_run_trap_internal (sig, tag) + int sig; + char *tag; +{ + char *trap_command, *old_trap; + int trap_exit_value, *token_state; + int save_return_catch_flag, function_code, flags; + procenv_t save_return_catch; + WORD_LIST *save_subst_varlist; + + trap_exit_value = function_code = 0; + /* Run the trap only if SIG is trapped and not ignored, and we are not + currently executing in the trap handler. */ + if ((sigmodes[sig] & SIG_TRAPPED) && ((sigmodes[sig] & SIG_IGNORED) == 0) && + (trap_list[sig] != (char *)IMPOSSIBLE_TRAP_HANDLER) && + ((sigmodes[sig] & SIG_INPROGRESS) == 0)) + { + old_trap = trap_list[sig]; + sigmodes[sig] |= SIG_INPROGRESS; + sigmodes[sig] &= ~SIG_CHANGED; /* just to be sure */ + trap_command = savestring (old_trap); + + running_trap = sig + 1; + trap_saved_exit_value = last_command_exit_value; + + token_state = save_token_state (); + save_subst_varlist = subst_assign_varlist; + subst_assign_varlist = 0; + + /* If we're in a function, make sure return longjmps come here, too. */ + save_return_catch_flag = return_catch_flag; + if (return_catch_flag) + { + COPY_PROCENV (return_catch, save_return_catch); + function_code = setjmp (return_catch); + } + + flags = SEVAL_NONINT|SEVAL_NOHIST; + if (sig != DEBUG_TRAP && sig != RETURN_TRAP && sig != ERROR_TRAP) + flags |= SEVAL_RESETLINE; + if (function_code == 0) + parse_and_execute (trap_command, tag, flags); + + restore_token_state (token_state); + free (token_state); + + subst_assign_varlist = save_subst_varlist; + + trap_exit_value = last_command_exit_value; + last_command_exit_value = trap_saved_exit_value; + running_trap = 0; + + sigmodes[sig] &= ~SIG_INPROGRESS; + + if (sigmodes[sig] & SIG_CHANGED) + { +#if 0 + /* Special traps like EXIT, DEBUG, RETURN are handled explicitly in + the places where they can be changed using unwind-protects. For + example, look at execute_cmd.c:execute_function(). */ + if (SPECIAL_TRAP (sig) == 0) +#endif + free (old_trap); + sigmodes[sig] &= ~SIG_CHANGED; + } + + if (save_return_catch_flag) + { + return_catch_flag = save_return_catch_flag; + return_catch_value = trap_exit_value; + COPY_PROCENV (save_return_catch, return_catch); + if (function_code) + longjmp (return_catch, 1); + } + } + + return trap_exit_value; +} + +int +run_debug_trap () +{ + int trap_exit_value; + pid_t save_pgrp; + int save_pipe[2]; + + /* XXX - question: should the DEBUG trap inherit the RETURN trap? */ + trap_exit_value = 0; + if ((sigmodes[DEBUG_TRAP] & SIG_TRAPPED) && ((sigmodes[DEBUG_TRAP] & SIG_IGNORED) == 0) && ((sigmodes[DEBUG_TRAP] & SIG_INPROGRESS) == 0)) + { +#if defined (JOB_CONTROL) + save_pgrp = pipeline_pgrp; + pipeline_pgrp = 0; + save_pipeline (1); +# if defined (PGRP_PIPE) + save_pgrp_pipe (save_pipe, 1); +# endif + stop_making_children (); +#endif + + trap_exit_value = _run_trap_internal (DEBUG_TRAP, "debug trap"); + +#if defined (JOB_CONTROL) + pipeline_pgrp = save_pgrp; + restore_pipeline (1); +# if defined (PGRP_PIPE) + close_pgrp_pipe (); + restore_pgrp_pipe (save_pipe); +# endif + if (pipeline_pgrp > 0) + give_terminal_to (pipeline_pgrp, 1); + notify_and_cleanup (); +#endif + +#if defined (DEBUGGER) + /* If we're in the debugger and the DEBUG trap returns 2 while we're in + a function or sourced script, we force a `return'. */ + if (debugging_mode && trap_exit_value == 2 && return_catch_flag) + { + return_catch_value = trap_exit_value; + longjmp (return_catch, 1); + } +#endif + } + return trap_exit_value; +} + +void +run_error_trap () +{ + if ((sigmodes[ERROR_TRAP] & SIG_TRAPPED) && ((sigmodes[ERROR_TRAP] & SIG_IGNORED) == 0) && (sigmodes[ERROR_TRAP] & SIG_INPROGRESS) == 0) + _run_trap_internal (ERROR_TRAP, "error trap"); +} + +void +run_return_trap () +{ + int old_exit_value; + +#if 0 + if ((sigmodes[DEBUG_TRAP] & SIG_TRAPPED) && (sigmodes[DEBUG_TRAP] & SIG_INPROGRESS)) + return; +#endif + + if ((sigmodes[RETURN_TRAP] & SIG_TRAPPED) && ((sigmodes[RETURN_TRAP] & SIG_IGNORED) == 0) && (sigmodes[RETURN_TRAP] & SIG_INPROGRESS) == 0) + { + old_exit_value = last_command_exit_value; + _run_trap_internal (RETURN_TRAP, "return trap"); + last_command_exit_value = old_exit_value; + } +} + +/* Run a trap set on SIGINT. This is called from throw_to_top_level (), and + declared here to localize the trap functions. */ +void +run_interrupt_trap () +{ + _run_trap_internal (SIGINT, "interrupt trap"); +} + +#ifdef INCLUDE_UNUSED +/* Free all the allocated strings in the list of traps and reset the trap + values to the default. Intended to be called from subshells that want + to complete work done by reset_signal_handlers upon execution of a + subsequent `trap' command that changes a signal's disposition. */ +void +free_trap_strings () +{ + register int i; + + for (i = 0; i < BASH_NSIG; i++) + free_trap_string (i); + trap_list[DEBUG_TRAP] = trap_list[EXIT_TRAP] = trap_list[ERROR_TRAP] = trap_list[RETURN_TRAP] = (char *)NULL; +} + +/* Free a trap command string associated with SIG without changing signal + disposition. Intended to be called from free_trap_strings() */ +static void +free_trap_string (sig) + int sig; +{ + change_signal (sig, (char *)DEFAULT_SIG); + sigmodes[sig] &= ~SIG_TRAPPED; +} +#endif + +/* Reset the handler for SIG to the original value. */ +static void +reset_signal (sig) + int sig; +{ + set_signal_handler (sig, original_signals[sig]); + sigmodes[sig] &= ~SIG_TRAPPED; +} + +/* Set the handler signal SIG to the original and free any trap + command associated with it. */ +static void +restore_signal (sig) + int sig; +{ + set_signal_handler (sig, original_signals[sig]); + change_signal (sig, (char *)DEFAULT_SIG); + sigmodes[sig] &= ~SIG_TRAPPED; +} + +static void +reset_or_restore_signal_handlers (reset) + sh_resetsig_func_t *reset; +{ + register int i; + + /* Take care of the exit trap first */ + if (sigmodes[EXIT_TRAP] & SIG_TRAPPED) + { + sigmodes[EXIT_TRAP] &= ~SIG_TRAPPED; + if (reset != reset_signal) + { + free_trap_command (EXIT_TRAP); + trap_list[EXIT_TRAP] = (char *)NULL; + } + } + + for (i = 1; i < NSIG; i++) + { + if (sigmodes[i] & SIG_TRAPPED) + { + if (trap_list[i] == (char *)IGNORE_SIG) + set_signal_handler (i, SIG_IGN); + else + (*reset) (i); + } + else if (sigmodes[i] & SIG_SPECIAL) + (*reset) (i); + } + + /* Command substitution and other child processes don't inherit the + debug, error, or return traps. If we're in the debugger, and the + `functrace' or `errtrace' options have been set, then let command + substitutions inherit them. Let command substitution inherit the + RETURN trap if we're in the debugger and tracing functions. */ + if (function_trace_mode == 0) + { + sigmodes[DEBUG_TRAP] &= ~SIG_TRAPPED; + sigmodes[RETURN_TRAP] &= ~SIG_TRAPPED; + } + if (error_trace_mode == 0) + sigmodes[ERROR_TRAP] &= ~SIG_TRAPPED; +} + +/* Reset trapped signals to their original values, but don't free the + trap strings. Called by the command substitution code. */ +void +reset_signal_handlers () +{ + reset_or_restore_signal_handlers (reset_signal); +} + +/* Reset all trapped signals to their original values. Signals set to be + ignored with trap '' SIGNAL should be ignored, so we make sure that they + are. Called by child processes after they are forked. */ +void +restore_original_signals () +{ + reset_or_restore_signal_handlers (restore_signal); +} + +/* If a trap handler exists for signal SIG, then call it; otherwise just + return failure. */ +int +maybe_call_trap_handler (sig) + int sig; +{ + /* Call the trap handler for SIG if the signal is trapped and not ignored. */ + if ((sigmodes[sig] & SIG_TRAPPED) && ((sigmodes[sig] & SIG_IGNORED) == 0)) + { + switch (sig) + { + case SIGINT: + run_interrupt_trap (); + break; + case EXIT_TRAP: + run_exit_trap (); + break; + case DEBUG_TRAP: + run_debug_trap (); + break; + case ERROR_TRAP: + run_error_trap (); + break; + default: + trap_handler (sig); + break; + } + return (1); + } + else + return (0); +} + +int +signal_is_trapped (sig) + int sig; +{ + return (sigmodes[sig] & SIG_TRAPPED); +} + +int +signal_is_special (sig) + int sig; +{ + return (sigmodes[sig] & SIG_SPECIAL); +} + +int +signal_is_ignored (sig) + int sig; +{ + return (sigmodes[sig] & SIG_IGNORED); +} + +void +set_signal_ignored (sig) + int sig; +{ + sigmodes[sig] |= SIG_HARD_IGNORE; + original_signals[sig] = SIG_IGN; +} + +int +signal_in_progress (sig) + int sig; +{ + return (sigmodes[sig] & SIG_INPROGRESS); +} |