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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-05 18:33:23 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-05 18:33:23 +0000
commit1d5cace9db9aef76f26b2d7ba54bbb76443b00b2 (patch)
tree314a15dd1aa103da13bdc83ba1d2105a290bc5ba /trap.c
parentInitial commit. (diff)
downloadbash-1d5cace9db9aef76f26b2d7ba54bbb76443b00b2.tar.xz
bash-1d5cace9db9aef76f26b2d7ba54bbb76443b00b2.zip
Adding upstream version 5.0.upstream/5.0upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'trap.c')
-rw-r--r--trap.c1393
1 files changed, 1393 insertions, 0 deletions
diff --git a/trap.c b/trap.c
new file mode 100644
index 0000000..3cb67cd
--- /dev/null
+++ b/trap.c
@@ -0,0 +1,1393 @@
+/* trap.c -- Not the trap command, but useful functions for manipulating
+ those objects. The trap command is in builtins/trap.def. */
+
+/* Copyright (C) 1987-2018 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 <signal.h>
+
+#include "trap.h"
+
+#include "shell.h"
+#include "execute_cmd.h"
+#include "flags.h"
+#include "parser.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"
+
+#if defined (READLINE)
+# include <readline/readline.h>
+# include "bashline.h"
+#endif
+
+#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 (int);
+static void change_signal (int, char *);
+
+static int _run_trap_internal (int, char *);
+
+static void free_trap_string (int);
+static void reset_signal (int);
+static void restore_signal (int);
+static void reset_or_restore_signal_handlers (sh_resetsig_func_t *);
+
+static void trap_if_untrapped (int, char *);
+
+/* Variables used here but defined in other files. */
+extern procenv_t alrmbuf;
+
+extern volatile int from_return_trap;
+
+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 received. 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;
+
+int trapped_signal_received;
+
+#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 SETORIGSIG(sig,handler) \
+ do { \
+ original_signals[sig] = handler; \
+ 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; /* XXX - only set, not used */
+ 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;
+ }
+
+ get_original_tty_job_signals ();
+}
+
+#ifdef DEBUG
+/* 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);
+
+#if defined (SIGRTMIN) && defined (SIGRTMAX)
+ if (STREQN (string, "SIGRTMIN+", 9) || ((flags & DSIG_NOCASE) && strncasecmp (string, "SIGRTMIN+", 9) == 0))
+ {
+ if (legal_number (string+9, &sig) && sig >= 0 && sig <= SIGRTMAX - SIGRTMIN)
+ return (SIGRTMIN + sig);
+ else
+ return NO_SIG;
+ }
+ else if (STREQN (string, "RTMIN+", 6) || ((flags & DSIG_NOCASE) && strncasecmp (string, "RTMIN+", 6) == 0))
+ {
+ if (legal_number (string+6, &sig) && sig >= 0 && sig <= SIGRTMAX - SIGRTMIN)
+ return (SIGRTMIN + sig);
+ else
+ return NO_SIG;
+ }
+#endif /* SIGRTMIN && SIGRTMAX */
+
+ /* 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 sensitively 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, x;
+ WORD_LIST *save_subst_varlist;
+ HASH_TABLE *save_tempenv;
+ sh_parser_state_t pstate;
+#if defined (ARRAY_VARS)
+ ARRAY *ps;
+#endif
+
+ if (catch_flag == 0) /* simple optimization */
+ return;
+
+ if (running_trap > 0)
+ {
+#if defined (DEBUG)
+ internal_warning ("run_pending_traps: recursive invocation while running trap for signal %d", running_trap-1);
+#endif
+#if defined (SIGWINCH)
+ if (running_trap == SIGWINCH+1 && pending_traps[SIGWINCH])
+ return; /* no recursive SIGWINCH trap invocations */
+#endif
+ /* could check for running the trap handler for the same signal here
+ (running_trap == sig+1) */
+ if (evalnest_max > 0 && evalnest > evalnest_max)
+ {
+ internal_error (_("trap handler: maximum trap handler level exceeded (%d)"), evalnest_max);
+ evalnest = 0;
+ jump_to_top_level (DISCARD);
+ }
+ }
+
+ catch_flag = trapped_signal_received = 0;
+
+ /* Preserve $? when running trap. */
+ trap_saved_exit_value = old_exit_value = last_command_exit_value;
+#if defined (ARRAY_VARS)
+ ps = save_pipestatus_array ();
+#endif
+
+ 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 (running_trap == sig+1)
+ /*continue*/;
+
+ running_trap = sig + 1;
+
+ if (sig == SIGINT)
+ {
+ pending_traps[sig] = 0; /* XXX */
+ /* We don't modify evalnest here, since run_interrupt_trap() calls
+ _run_trap_internal, which does. */
+ run_interrupt_trap (0);
+ CLRINTERRUPT; /* interrupts don't stack */
+ }
+#if defined (JOB_CONTROL) && defined (SIGCHLD)
+ else if (sig == SIGCHLD &&
+ trap_list[SIGCHLD] != (char *)IMPOSSIBLE_TRAP_HANDLER &&
+ (sigmodes[SIGCHLD] & SIG_INPROGRESS) == 0)
+ {
+ sigmodes[SIGCHLD] |= SIG_INPROGRESS;
+ /* We modify evalnest here even though run_sigchld_trap can run
+ the trap action more than once */
+ evalnest++;
+ x = pending_traps[sig];
+ pending_traps[sig] = 0;
+ run_sigchld_trap (x); /* use as counter */
+ running_trap = 0;
+ evalnest--;
+ sigmodes[SIGCHLD] &= ~SIG_INPROGRESS;
+ /* continue here rather than reset pending_traps[SIGCHLD] below in
+ case there are recursive calls to run_pending_traps and children
+ have been reaped while run_sigchld_trap was running. */
+ continue;
+ }
+ else if (sig == SIGCHLD &&
+ trap_list[SIGCHLD] == (char *)IMPOSSIBLE_TRAP_HANDLER &&
+ (sigmodes[SIGCHLD] & SIG_INPROGRESS) != 0)
+ {
+ /* This can happen when run_pending_traps is called while
+ running a SIGCHLD trap handler. */
+ running_trap = 0;
+ /* want to leave pending_traps[SIGCHLD] alone here */
+ continue; /* XXX */
+ }
+ else if (sig == SIGCHLD && (sigmodes[SIGCHLD] & SIG_INPROGRESS))
+ {
+ /* whoops -- print warning? */
+ running_trap = 0; /* XXX */
+ /* want to leave pending_traps[SIGCHLD] alone here */
+ continue;
+ }
+#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
+ {
+ /* XXX - should we use save_parser_state/restore_parser_state? */
+ save_parser_state (&pstate);
+ save_subst_varlist = subst_assign_varlist;
+ subst_assign_varlist = 0;
+ save_tempenv = temporary_env;
+ temporary_env = 0; /* traps should not run with temporary env */
+
+#if defined (JOB_CONTROL)
+ save_pipeline (1); /* XXX only provides one save level */
+#endif
+ /* XXX - set pending_traps[sig] = 0 here? */
+ pending_traps[sig] = 0;
+ evalnest++;
+ evalstring (savestring (trap_list[sig]), "trap", SEVAL_NONINT|SEVAL_NOHIST|SEVAL_RESETLINE);
+ evalnest--;
+#if defined (JOB_CONTROL)
+ restore_pipeline (1);
+#endif
+
+ subst_assign_varlist = save_subst_varlist;
+ restore_parser_state (&pstate);
+ temporary_env = save_tempenv;
+ }
+
+ pending_traps[sig] = 0; /* XXX - move before evalstring? */
+ running_trap = 0;
+ }
+ }
+
+#if defined (ARRAY_VARS)
+ restore_pipestatus_array (ps);
+#endif
+ 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]++;
+ trapped_signal_received = sig;
+
+ if (this_shell_builtin && (this_shell_builtin == wait_builtin))
+ {
+ wait_signal_received = sig;
+ if (interrupt_immediately && wait_intr_flag)
+ sh_longjmp (wait_intr_buf, 1);
+ }
+
+#if defined (READLINE)
+ /* Set the event hook so readline will call it after the signal handlers
+ finish executing, so if this interrupted character input we can get
+ quick response. */
+ if (RL_ISSTATE (RL_STATE_SIGHANDLER) && interrupt_immediately == 0)
+ bashline_set_event_hook ();
+#endif
+
+ if (interrupt_immediately)
+ run_pending_traps ();
+
+ errno = oerrno;
+ }
+
+ SIGRETURN (0);
+}
+
+int
+first_pending_trap ()
+{
+ register int i;
+
+ for (i = 1; i < NSIG; i++)
+ if (pending_traps[i])
+ return i;
+ return -1;
+}
+
+/* Return > 0 if any of the "real" signals (not fake signals like EXIT) are
+ trapped. */
+int
+any_signals_trapped ()
+{
+ register int i;
+
+ for (i = 1; i < NSIG; i++)
+ if (sigmodes[i] & SIG_TRAPPED)
+ return i;
+ return -1;
+}
+
+void
+check_signals ()
+{
+ CHECK_ALRM; /* set by the read builtin */
+ QUIT;
+}
+
+/* Convenience functions the rest of the shell can use */
+void
+check_signals_and_traps ()
+{
+ check_signals ();
+
+ run_pending_traps ();
+}
+
+#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 */
+}
+
+/* Act as if we received SIGCHLD NCHILD times and increment
+ pending_traps[SIGCHLD] by that amount. This allows us to still run the
+ SIGCHLD trap once for each exited child. */
+void
+queue_sigchld_trap (nchild)
+ int nchild;
+{
+ if (nchild > 0)
+ {
+ catch_flag = 1;
+ pending_traps[SIGCHLD] += nchild;
+ trapped_signal_received = SIGCHLD;
+ }
+}
+#endif /* JOB_CONTROL && SIGCHLD */
+
+/* Set a trap for SIG only if SIG is not already trapped. */
+static inline void
+trap_if_untrapped (sig, command)
+ int sig;
+ char *command;
+{
+ if ((sigmodes[sig] & SIG_TRAPPED) == 0)
+ set_signal (sig, command);
+}
+
+void
+set_debug_trap (command)
+ char *command;
+{
+ set_signal (DEBUG_TRAP, command);
+}
+
+/* Separate function to call when functions and sourced files want to restore
+ the original version of the DEBUG trap before returning. Unless the -T
+ option is set, source and shell function execution save the old debug trap
+ and unset the trap. If the function or sourced file changes the DEBUG trap,
+ SIG_TRAPPED will be set and we don't bother restoring the original trap string.
+ This is used by both functions and the source builtin. */
+void
+maybe_set_debug_trap (command)
+ char *command;
+{
+ trap_if_untrapped (DEBUG_TRAP, command);
+}
+
+void
+set_error_trap (command)
+ char *command;
+{
+ set_signal (ERROR_TRAP, command);
+}
+
+void
+maybe_set_error_trap (command)
+ char *command;
+{
+ trap_if_untrapped (ERROR_TRAP, command);
+}
+
+void
+set_return_trap (command)
+ char *command;
+{
+ set_signal (RETURN_TRAP, command);
+}
+
+void
+maybe_set_return_trap (command)
+ char *command;
+{
+ trap_if_untrapped (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;
+{
+ sigset_t set, oset;
+
+ 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)
+ {
+ BLOCK_SIGNAL (sig, set, oset);
+ change_signal (sig, savestring (string));
+ set_signal_handler (sig, trap_handler);
+ UNBLOCK_SIGNAL (oset);
+ }
+ 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;
+}
+
+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);
+}
+
+void
+get_all_original_signals ()
+{
+ register int i;
+
+ for (i = 1; i < NSIG; i++)
+ GET_ORIGINAL_SIGNAL (i);
+}
+
+void
+set_original_signal (sig, handler)
+ int sig;
+ SigHandler *handler;
+{
+ if (sig > 0 && sig < NSIG && original_signals[sig] == (SigHandler *)IMPOSSIBLE_TRAP_HANDLER)
+ SETORIGSIG (sig, handler);
+}
+
+/* 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. */
+ /* We special-case SIGCHLD and IMPOSSIBLE_TRAP_HANDLER (see above) as a
+ sentinel to determine whether or not disposition is reset to the default
+ while the trap handler is executing. */
+ if (((sigmodes[sig] & SIG_TRAPPED) == 0) &&
+ (sig != SIGCHLD || (sigmodes[sig] & SIG_INPROGRESS) == 0 || trap_list[sig] != (char *)IMPOSSIBLE_TRAP_HANDLER))
+ 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;
+#if defined (ARRAY_VARS)
+ ARRAY *ps;
+#endif
+
+ trap_saved_exit_value = last_command_exit_value;
+#if defined (ARRAY_VARS)
+ ps = save_pipestatus_array ();
+#endif
+ 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_nosigs (top_level);
+
+ /* If we're in a function, make sure return longjmps come here, too. */
+ if (return_catch_flag)
+ function_code = setjmp_nosigs (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;
+#if defined (ARRAY_VARS)
+ array_dispose (ps);
+#endif
+
+ return retval;
+ }
+
+#if defined (ARRAY_VARS)
+ restore_pipestatus_array (ps);
+#endif
+ return (trap_saved_exit_value);
+}
+
+void
+run_trap_cleanup (sig)
+ int sig;
+{
+ sigmodes[sig] &= ~(SIG_INPROGRESS|SIG_CHANGED);
+}
+
+#define RECURSIVE_SIG(s) (SPECIAL_TRAP(s) == 0)
+
+/* 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;
+ volatile int save_return_catch_flag, function_code, old_int;
+ int flags;
+ procenv_t save_return_catch;
+ WORD_LIST *save_subst_varlist;
+ HASH_TABLE *save_tempenv;
+ sh_parser_state_t pstate;
+#if defined (ARRAY_VARS)
+ ARRAY *ps;
+#endif
+
+ trap_exit_value = function_code = 0;
+ trap_saved_exit_value = last_command_exit_value;
+ /* 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) &&
+#if 0
+ /* Uncomment this to allow some special signals to recursively execute
+ trap handlers. */
+ (RECURSIVE_SIG (sig) || (sigmodes[sig] & SIG_INPROGRESS) == 0))
+#else
+ ((sigmodes[sig] & SIG_INPROGRESS) == 0))
+#endif
+ {
+ 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;
+
+ old_int = interrupt_state; /* temporarily suppress pending interrupts */
+ CLRINTERRUPT;
+
+#if defined (ARRAY_VARS)
+ ps = save_pipestatus_array ();
+#endif
+
+ save_parser_state (&pstate);
+ save_subst_varlist = subst_assign_varlist;
+ subst_assign_varlist = 0;
+ save_tempenv = temporary_env;
+ temporary_env = 0; /* traps should not run with temporary env */
+
+#if defined (JOB_CONTROL)
+ if (sig != DEBUG_TRAP) /* run_debug_trap does this */
+ save_pipeline (1); /* XXX only provides one save level */
+#endif
+
+ /* 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_nosigs (return_catch);
+ }
+
+ flags = SEVAL_NONINT|SEVAL_NOHIST;
+ if (sig != DEBUG_TRAP && sig != RETURN_TRAP && sig != ERROR_TRAP)
+ flags |= SEVAL_RESETLINE;
+ evalnest++;
+ if (function_code == 0)
+ {
+ parse_and_execute (trap_command, tag, flags);
+ trap_exit_value = last_command_exit_value;
+ }
+ else
+ trap_exit_value = return_catch_value;
+ evalnest--;
+
+#if defined (JOB_CONTROL)
+ if (sig != DEBUG_TRAP) /* run_debug_trap does this */
+ restore_pipeline (1);
+#endif
+
+ subst_assign_varlist = save_subst_varlist;
+ restore_parser_state (&pstate);
+
+#if defined (ARRAY_VARS)
+ restore_pipestatus_array (ps);
+#endif
+
+ temporary_env = save_tempenv;
+
+ sigmodes[sig] &= ~SIG_INPROGRESS;
+ running_trap = 0;
+ interrupt_state = old_int;
+
+ 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;
+
+ CHECK_TERMSIG; /* some pathological conditions lead here */
+ }
+
+ 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)
+ {
+#if 0
+ from_return_trap = sig == RETURN_TRAP;
+#endif
+ sh_longjmp (return_catch, 1);
+ }
+ }
+ }
+
+ return trap_exit_value;
+}
+
+int
+run_debug_trap ()
+{
+ int trap_exit_value, old_verbose;
+ pid_t save_pgrp;
+#if defined (PGRP_PIPE)
+ int save_pipe[2];
+#endif
+
+ /* 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
+
+ old_verbose = echo_input_at_read;
+#if 0 /* not yet */
+ echo_input_at_read = 0;
+#endif
+
+ trap_exit_value = _run_trap_internal (DEBUG_TRAP, "debug trap");
+
+ echo_input_at_read = old_verbose;
+
+#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 && ((subshell_environment & (SUBSHELL_ASYNC|SUBSHELL_PIPE)) == 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;
+ sh_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 (will_throw)
+ int will_throw; /* from throw_to_top_level? */
+{
+ if (will_throw && running_trap > 0)
+ run_trap_cleanup (running_trap - 1);
+ _run_trap_internal (SIGINT, "interrupt trap");
+}
+
+/* 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. We need
+ to make sure that we duplicate the behavior of
+ reset_or_restore_signal_handlers and not change the disposition of signals
+ that are set to be ignored. */
+void
+free_trap_strings ()
+{
+ register int i;
+
+ for (i = 0; i < NSIG; i++)
+ {
+ if (trap_list[i] != (char *)IGNORE_SIG)
+ free_trap_string (i);
+ }
+ for (i = NSIG; i < BASH_NSIG; i++)
+ {
+ /* Don't free the trap string if the subshell inherited the trap */
+ if ((sigmodes[i] & SIG_TRAPPED) == 0)
+ {
+ free_trap_string (i);
+ trap_list[i] = (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; /* XXX - SIG_INPROGRESS? */
+}
+
+/* Reset the handler for SIG to the original value but leave the trap string
+ in place. */
+static void
+reset_signal (sig)
+ int sig;
+{
+ set_signal_handler (sig, original_signals[sig]);
+ sigmodes[sig] &= ~SIG_TRAPPED; /* XXX - SIG_INPROGRESS? */
+}
+
+/* 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; /* XXX - SIG_INPROGRESS? */
+ 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);
+ pending_traps[i] = 0; /* XXX */
+ }
+
+ /* 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 and other places
+ that create a "subshell environment". */
+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. Returns 1 if it called the trap handler. */
+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 (0);
+ 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_pending (sig)
+ int sig;
+{
+ return (pending_traps[sig]);
+}
+
+int
+signal_is_special (sig)
+ int sig;
+{
+ return (sigmodes[sig] & SIG_SPECIAL);
+}
+
+int
+signal_is_ignored (sig)
+ int sig;
+{
+ return (sigmodes[sig] & SIG_IGNORED);
+}
+
+int
+signal_is_hard_ignored (sig)
+ int sig;
+{
+ return (sigmodes[sig] & SIG_HARD_IGNORE);
+}
+
+void
+set_signal_hard_ignored (sig)
+ int sig;
+{
+ sigmodes[sig] |= SIG_HARD_IGNORE;
+ original_signals[sig] = SIG_IGN;
+}
+
+void
+set_signal_ignored (sig)
+ int sig;
+{
+ original_signals[sig] = SIG_IGN;
+}
+
+int
+signal_in_progress (sig)
+ int sig;
+{
+ return (sigmodes[sig] & SIG_INPROGRESS);
+}