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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 /sig.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 'sig.c')
-rw-r--r--sig.c782
1 files changed, 782 insertions, 0 deletions
diff --git a/sig.c b/sig.c
new file mode 100644
index 0000000..f8a0e0f
--- /dev/null
+++ b/sig.c
@@ -0,0 +1,782 @@
+/* sig.c - interface for shell signal handlers and signal initialization. */
+
+/* Copyright (C) 1994-2018 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"
+
+#include "bashtypes.h"
+
+#if defined (HAVE_UNISTD_H)
+# ifdef _MINIX
+# include <sys/types.h>
+# endif
+# include <unistd.h>
+#endif
+
+#include <stdio.h>
+#include <signal.h>
+
+#include "bashintl.h"
+
+#include "shell.h"
+#include "execute_cmd.h"
+#if defined (JOB_CONTROL)
+#include "jobs.h"
+#endif /* JOB_CONTROL */
+#include "siglist.h"
+#include "sig.h"
+#include "trap.h"
+
+#include "builtins/common.h"
+#include "builtins/builtext.h"
+
+#if defined (READLINE)
+# include "bashline.h"
+# include <readline/readline.h>
+#endif
+
+#if defined (HISTORY)
+# include "bashhist.h"
+#endif
+
+extern void initialize_siglist ();
+
+#if !defined (JOB_CONTROL)
+extern void initialize_job_signals __P((void));
+#endif
+
+/* Non-zero after SIGINT. */
+volatile sig_atomic_t interrupt_state = 0;
+
+/* Non-zero after SIGWINCH */
+volatile sig_atomic_t sigwinch_received = 0;
+
+/* Non-zero after SIGTERM */
+volatile sig_atomic_t sigterm_received = 0;
+
+/* Set to the value of any terminating signal received. */
+volatile sig_atomic_t terminating_signal = 0;
+
+/* The environment at the top-level R-E loop. We use this in
+ the case of error return. */
+procenv_t top_level;
+
+#if defined (JOB_CONTROL) || defined (HAVE_POSIX_SIGNALS)
+/* The signal masks that this shell runs with. */
+sigset_t top_level_mask;
+#endif /* JOB_CONTROL */
+
+/* When non-zero, we throw_to_top_level (). */
+int interrupt_immediately = 0;
+
+/* When non-zero, we call the terminating signal handler immediately. */
+int terminate_immediately = 0;
+
+#if defined (SIGWINCH)
+static SigHandler *old_winch = (SigHandler *)SIG_DFL;
+#endif
+
+static void initialize_shell_signals __P((void));
+
+void
+initialize_signals (reinit)
+ int reinit;
+{
+ initialize_shell_signals ();
+ initialize_job_signals ();
+#if !defined (HAVE_SYS_SIGLIST) && !defined (HAVE_UNDER_SYS_SIGLIST) && !defined (HAVE_STRSIGNAL)
+ if (reinit == 0)
+ initialize_siglist ();
+#endif /* !HAVE_SYS_SIGLIST && !HAVE_UNDER_SYS_SIGLIST && !HAVE_STRSIGNAL */
+}
+
+/* A structure describing a signal that terminates the shell if not
+ caught. The orig_handler member is present so children can reset
+ these signals back to their original handlers. */
+struct termsig {
+ int signum;
+ SigHandler *orig_handler;
+ int orig_flags;
+ int core_dump;
+};
+
+#define NULL_HANDLER (SigHandler *)SIG_DFL
+
+/* The list of signals that would terminate the shell if not caught.
+ We catch them, but just so that we can write the history file,
+ and so forth. */
+static struct termsig terminating_signals[] = {
+#ifdef SIGHUP
+{ SIGHUP, NULL_HANDLER, 0 },
+#endif
+
+#ifdef SIGINT
+{ SIGINT, NULL_HANDLER, 0 },
+#endif
+
+#ifdef SIGILL
+{ SIGILL, NULL_HANDLER, 0, 1},
+#endif
+
+#ifdef SIGTRAP
+{ SIGTRAP, NULL_HANDLER, 0, 1 },
+#endif
+
+#ifdef SIGIOT
+{ SIGIOT, NULL_HANDLER, 0, 1 },
+#endif
+
+#ifdef SIGDANGER
+{ SIGDANGER, NULL_HANDLER, 0 },
+#endif
+
+#ifdef SIGEMT
+{ SIGEMT, NULL_HANDLER, 0 },
+#endif
+
+#ifdef SIGFPE
+{ SIGFPE, NULL_HANDLER, 0, 1 },
+#endif
+
+#ifdef SIGBUS
+{ SIGBUS, NULL_HANDLER, 0, 1 },
+#endif
+
+#ifdef SIGSEGV
+{ SIGSEGV, NULL_HANDLER, 0, 1 },
+#endif
+
+#ifdef SIGSYS
+{ SIGSYS, NULL_HANDLER, 0, 1 },
+#endif
+
+#ifdef SIGPIPE
+{ SIGPIPE, NULL_HANDLER, 0 },
+#endif
+
+#ifdef SIGALRM
+{ SIGALRM, NULL_HANDLER, 0 },
+#endif
+
+#ifdef SIGTERM
+{ SIGTERM, NULL_HANDLER, 0 },
+#endif
+
+/* These don't generate core dumps on anything but Linux, but we're doing
+ this just for Linux anyway. */
+#ifdef SIGXCPU
+{ SIGXCPU, NULL_HANDLER, 0, 1 },
+#endif
+
+#ifdef SIGXFSZ
+{ SIGXFSZ, NULL_HANDLER, 0, 1 },
+#endif
+
+#ifdef SIGVTALRM
+{ SIGVTALRM, NULL_HANDLER, 0 },
+#endif
+
+#if 0
+#ifdef SIGPROF
+{ SIGPROF, NULL_HANDLER, 0 },
+#endif
+#endif
+
+#ifdef SIGLOST
+{ SIGLOST, NULL_HANDLER, 0 },
+#endif
+
+#ifdef SIGUSR1
+{ SIGUSR1, NULL_HANDLER, 0 },
+#endif
+
+#ifdef SIGUSR2
+{ SIGUSR2, NULL_HANDLER, 0 },
+#endif
+};
+
+#define TERMSIGS_LENGTH (sizeof (terminating_signals) / sizeof (struct termsig))
+
+#define XSIG(x) (terminating_signals[x].signum)
+#define XHANDLER(x) (terminating_signals[x].orig_handler)
+#define XSAFLAGS(x) (terminating_signals[x].orig_flags)
+#define XCOREDUMP(x) (terminating_signals[x].core_dump)
+
+static int termsigs_initialized = 0;
+
+/* Initialize signals that will terminate the shell to do some
+ unwind protection. For non-interactive shells, we only call
+ this when a trap is defined for EXIT (0) or when trap is run
+ to display signal dispositions. */
+void
+initialize_terminating_signals ()
+{
+ register int i;
+#if defined (HAVE_POSIX_SIGNALS)
+ struct sigaction act, oact;
+#endif
+
+ if (termsigs_initialized)
+ return;
+
+ /* The following code is to avoid an expensive call to
+ set_signal_handler () for each terminating_signals. Fortunately,
+ this is possible in Posix. Unfortunately, we have to call signal ()
+ on non-Posix systems for each signal in terminating_signals. */
+#if defined (HAVE_POSIX_SIGNALS)
+ act.sa_handler = termsig_sighandler;
+ act.sa_flags = 0;
+ sigemptyset (&act.sa_mask);
+ sigemptyset (&oact.sa_mask);
+ for (i = 0; i < TERMSIGS_LENGTH; i++)
+ sigaddset (&act.sa_mask, XSIG (i));
+ for (i = 0; i < TERMSIGS_LENGTH; i++)
+ {
+ /* If we've already trapped it, don't do anything. */
+ if (signal_is_trapped (XSIG (i)))
+ continue;
+
+ sigaction (XSIG (i), &act, &oact);
+ XHANDLER(i) = oact.sa_handler;
+ XSAFLAGS(i) = oact.sa_flags;
+ /* Don't do anything with signals that are ignored at shell entry
+ if the shell is not interactive. */
+ /* XXX - should we do this for interactive shells, too? */
+ if (interactive_shell == 0 && XHANDLER (i) == SIG_IGN)
+ {
+ sigaction (XSIG (i), &oact, &act);
+ set_signal_hard_ignored (XSIG (i));
+ }
+#if defined (SIGPROF) && !defined (_MINIX)
+ if (XSIG (i) == SIGPROF && XHANDLER (i) != SIG_DFL && XHANDLER (i) != SIG_IGN)
+ sigaction (XSIG (i), &oact, (struct sigaction *)NULL);
+#endif /* SIGPROF && !_MINIX */
+ }
+#else /* !HAVE_POSIX_SIGNALS */
+
+ for (i = 0; i < TERMSIGS_LENGTH; i++)
+ {
+ /* If we've already trapped it, don't do anything. */
+ if (signal_is_trapped (XSIG (i)))
+ continue;
+
+ XHANDLER(i) = signal (XSIG (i), termsig_sighandler);
+ XSAFLAGS(i) = 0;
+ /* Don't do anything with signals that are ignored at shell entry
+ if the shell is not interactive. */
+ /* XXX - should we do this for interactive shells, too? */
+ if (interactive_shell == 0 && XHANDLER (i) == SIG_IGN)
+ {
+ signal (XSIG (i), SIG_IGN);
+ set_signal_hard_ignored (XSIG (i));
+ }
+#ifdef SIGPROF
+ if (XSIG (i) == SIGPROF && XHANDLER (i) != SIG_DFL && XHANDLER (i) != SIG_IGN)
+ signal (XSIG (i), XHANDLER (i));
+#endif
+ }
+
+#endif /* !HAVE_POSIX_SIGNALS */
+
+ termsigs_initialized = 1;
+}
+
+static void
+initialize_shell_signals ()
+{
+ if (interactive)
+ initialize_terminating_signals ();
+
+#if defined (JOB_CONTROL) || defined (HAVE_POSIX_SIGNALS)
+ /* All shells use the signal mask they inherit, and pass it along
+ to child processes. Children will never block SIGCHLD, though. */
+ sigemptyset (&top_level_mask);
+ sigprocmask (SIG_BLOCK, (sigset_t *)NULL, &top_level_mask);
+# if defined (SIGCHLD)
+ sigdelset (&top_level_mask, SIGCHLD);
+# endif
+#endif /* JOB_CONTROL || HAVE_POSIX_SIGNALS */
+
+ /* And, some signals that are specifically ignored by the shell. */
+ set_signal_handler (SIGQUIT, SIG_IGN);
+
+ if (interactive)
+ {
+ set_signal_handler (SIGINT, sigint_sighandler);
+ get_original_signal (SIGTERM);
+ if (signal_is_hard_ignored (SIGTERM) == 0)
+ set_signal_handler (SIGTERM, sigterm_sighandler);
+ set_sigwinch_handler ();
+ }
+}
+
+void
+reset_terminating_signals ()
+{
+ register int i;
+#if defined (HAVE_POSIX_SIGNALS)
+ struct sigaction act;
+#endif
+
+ if (termsigs_initialized == 0)
+ return;
+
+#if defined (HAVE_POSIX_SIGNALS)
+ act.sa_flags = 0;
+ sigemptyset (&act.sa_mask);
+ for (i = 0; i < TERMSIGS_LENGTH; i++)
+ {
+ /* Skip a signal if it's trapped or handled specially, because the
+ trap code will restore the correct value. */
+ if (signal_is_trapped (XSIG (i)) || signal_is_special (XSIG (i)))
+ continue;
+
+ act.sa_handler = XHANDLER (i);
+ act.sa_flags = XSAFLAGS (i);
+ sigaction (XSIG (i), &act, (struct sigaction *) NULL);
+ }
+#else /* !HAVE_POSIX_SIGNALS */
+ for (i = 0; i < TERMSIGS_LENGTH; i++)
+ {
+ if (signal_is_trapped (XSIG (i)) || signal_is_special (XSIG (i)))
+ continue;
+
+ signal (XSIG (i), XHANDLER (i));
+ }
+#endif /* !HAVE_POSIX_SIGNALS */
+
+ termsigs_initialized = 0;
+}
+#undef XHANDLER
+
+/* Run some of the cleanups that should be performed when we run
+ jump_to_top_level from a builtin command context. XXX - might want to
+ also call reset_parser here. */
+void
+top_level_cleanup ()
+{
+ /* Clean up string parser environment. */
+ while (parse_and_execute_level)
+ parse_and_execute_cleanup (-1);
+
+#if defined (PROCESS_SUBSTITUTION)
+ unlink_fifo_list ();
+#endif /* PROCESS_SUBSTITUTION */
+
+ run_unwind_protects ();
+ loop_level = continuing = breaking = funcnest = 0;
+ executing_list = comsub_ignore_return = return_catch_flag = wait_intr_flag = 0;
+}
+
+/* What to do when we've been interrupted, and it is safe to handle it. */
+void
+throw_to_top_level ()
+{
+ int print_newline = 0;
+
+ if (interrupt_state)
+ {
+ if (last_command_exit_value < 128)
+ last_command_exit_value = 128 + SIGINT;
+ print_newline = 1;
+ DELINTERRUPT;
+ }
+
+ if (interrupt_state)
+ return;
+
+ last_command_exit_signal = (last_command_exit_value > 128) ?
+ (last_command_exit_value - 128) : 0;
+ last_command_exit_value |= 128;
+
+ /* Run any traps set on SIGINT, mostly for interactive shells */
+ if (signal_is_trapped (SIGINT))
+ run_interrupt_trap (1);
+
+ /* Clean up string parser environment. */
+ while (parse_and_execute_level)
+ parse_and_execute_cleanup (-1);
+
+ if (running_trap > 0)
+ run_trap_cleanup (running_trap - 1);
+
+#if defined (JOB_CONTROL)
+ give_terminal_to (shell_pgrp, 0);
+#endif /* JOB_CONTROL */
+
+#if defined (JOB_CONTROL) || defined (HAVE_POSIX_SIGNALS)
+ /* This needs to stay because jobs.c:make_child() uses it without resetting
+ the signal mask. */
+ sigprocmask (SIG_SETMASK, &top_level_mask, (sigset_t *)NULL);
+#endif
+
+ reset_parser ();
+
+#if defined (READLINE)
+ if (interactive)
+ bashline_reset ();
+#endif /* READLINE */
+
+#if defined (PROCESS_SUBSTITUTION)
+ unlink_fifo_list ();
+#endif /* PROCESS_SUBSTITUTION */
+
+ run_unwind_protects ();
+ loop_level = continuing = breaking = funcnest = 0;
+ executing_list = comsub_ignore_return = return_catch_flag = wait_intr_flag = 0;
+
+ if (interactive && print_newline)
+ {
+ fflush (stdout);
+ fprintf (stderr, "\n");
+ fflush (stderr);
+ }
+
+ /* An interrupted `wait' command in a script does not exit the script. */
+ if (interactive || (interactive_shell && !shell_initialized) ||
+ (print_newline && signal_is_trapped (SIGINT)))
+ jump_to_top_level (DISCARD);
+ else
+ jump_to_top_level (EXITPROG);
+}
+
+/* This is just here to isolate the longjmp calls. */
+void
+jump_to_top_level (value)
+ int value;
+{
+ sh_longjmp (top_level, value);
+}
+
+sighandler
+termsig_sighandler (sig)
+ int sig;
+{
+ /* If we get called twice with the same signal before handling it,
+ terminate right away. */
+ if (
+#ifdef SIGHUP
+ sig != SIGHUP &&
+#endif
+#ifdef SIGINT
+ sig != SIGINT &&
+#endif
+#ifdef SIGDANGER
+ sig != SIGDANGER &&
+#endif
+#ifdef SIGPIPE
+ sig != SIGPIPE &&
+#endif
+#ifdef SIGALRM
+ sig != SIGALRM &&
+#endif
+#ifdef SIGTERM
+ sig != SIGTERM &&
+#endif
+#ifdef SIGXCPU
+ sig != SIGXCPU &&
+#endif
+#ifdef SIGXFSZ
+ sig != SIGXFSZ &&
+#endif
+#ifdef SIGVTALRM
+ sig != SIGVTALRM &&
+#endif
+#ifdef SIGLOST
+ sig != SIGLOST &&
+#endif
+#ifdef SIGUSR1
+ sig != SIGUSR1 &&
+#endif
+#ifdef SIGUSR2
+ sig != SIGUSR2 &&
+#endif
+ sig == terminating_signal)
+ terminate_immediately = 1;
+
+ terminating_signal = sig;
+
+ /* XXX - should this also trigger when interrupt_immediately is set? */
+ if (terminate_immediately)
+ {
+#if defined (HISTORY)
+ /* XXX - will inhibit history file being written */
+# if defined (READLINE)
+ if (interactive_shell == 0 || interactive == 0 || (sig != SIGHUP && sig != SIGTERM) || no_line_editing || (RL_ISSTATE (RL_STATE_READCMD) == 0))
+# endif
+ history_lines_this_session = 0;
+#endif
+ terminate_immediately = 0;
+ termsig_handler (sig);
+ }
+
+#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 readline is active or has modified the terminal we
+ need to set this no matter what the signal is, though the check for
+ RL_STATE_TERMPREPPED is possibly redundant. */
+ if (RL_ISSTATE (RL_STATE_SIGHANDLER) || RL_ISSTATE (RL_STATE_TERMPREPPED))
+ bashline_set_event_hook ();
+#endif
+
+ SIGRETURN (0);
+}
+
+void
+termsig_handler (sig)
+ int sig;
+{
+ static int handling_termsig = 0;
+ int i, core;
+ sigset_t mask;
+
+ /* Simple semaphore to keep this function from being executed multiple
+ times. Since we no longer are running as a signal handler, we don't
+ block multiple occurrences of the terminating signals while running. */
+ if (handling_termsig)
+ return;
+ handling_termsig = 1;
+ terminating_signal = 0; /* keep macro from re-testing true. */
+
+ /* I don't believe this condition ever tests true. */
+ if (sig == SIGINT && signal_is_trapped (SIGINT))
+ run_interrupt_trap (0);
+
+#if defined (HISTORY)
+ /* If we don't do something like this, the history will not be saved when
+ an interactive shell is running in a terminal window that gets closed
+ with the `close' button. We can't test for RL_STATE_READCMD because
+ readline no longer handles SIGTERM synchronously. */
+ if (interactive_shell && interactive && (sig == SIGHUP || sig == SIGTERM) && remember_on_history)
+ maybe_save_shell_history ();
+#endif /* HISTORY */
+
+ if (this_shell_builtin == read_builtin)
+ read_tty_cleanup ();
+
+#if defined (JOB_CONTROL)
+ if (sig == SIGHUP && (interactive || (subshell_environment & (SUBSHELL_COMSUB|SUBSHELL_PROCSUB))))
+ hangup_all_jobs ();
+
+ if ((subshell_environment & (SUBSHELL_COMSUB|SUBSHELL_PROCSUB)) == 0)
+ end_job_control ();
+#endif /* JOB_CONTROL */
+
+#if defined (PROCESS_SUBSTITUTION)
+ unlink_fifo_list ();
+#endif /* PROCESS_SUBSTITUTION */
+
+ /* Reset execution context */
+ loop_level = continuing = breaking = funcnest = 0;
+ executing_list = comsub_ignore_return = return_catch_flag = wait_intr_flag = 0;
+
+ run_exit_trap (); /* XXX - run exit trap possibly in signal context? */
+
+ /* We don't change the set of blocked signals. If a user starts the shell
+ with a terminating signal blocked, we won't get here (and if by some
+ magic chance we do, we'll exit below). */
+ set_signal_handler (sig, SIG_DFL);
+
+ kill (getpid (), sig);
+
+ if (dollar_dollar_pid != 1)
+ exit (128+sig); /* just in case the kill fails? */
+
+ /* We get here only under extraordinary circumstances. */
+
+ /* We are PID 1, and the kill above failed to kill the process. We assume
+ this means that we are running as an init process in a pid namespace
+ on Linux. In this case, we can't send ourselves a fatal signal, so we
+ determine whether or not we should have generated a core dump with the
+ kill call and attempt to trick the kernel into generating one if
+ necessary. */
+ sigprocmask (SIG_SETMASK, (sigset_t *)NULL, &mask);
+ for (i = core = 0; i < TERMSIGS_LENGTH; i++)
+ {
+ set_signal_handler (XSIG (i), SIG_DFL);
+ sigdelset (&mask, XSIG (i));
+ if (sig == XSIG (i))
+ core = XCOREDUMP (i);
+ }
+ sigprocmask (SIG_SETMASK, &mask, (sigset_t *)NULL);
+
+ if (core)
+ *((volatile unsigned long *) NULL) = 0xdead0000 + sig; /* SIGSEGV */
+
+ exit (128+sig);
+}
+#undef XSIG
+
+/* What we really do when SIGINT occurs. */
+sighandler
+sigint_sighandler (sig)
+ int sig;
+{
+#if defined (MUST_REINSTALL_SIGHANDLERS)
+ signal (sig, sigint_sighandler);
+#endif
+
+ /* interrupt_state needs to be set for the stack of interrupts to work
+ right. Should it be set unconditionally? */
+ if (interrupt_state == 0)
+ ADDINTERRUPT;
+
+ /* We will get here in interactive shells with job control active; allow
+ an interactive wait to be interrupted. wait_intr_flag is only set during
+ the execution of the wait builtin and when wait_intr_buf is valid. */
+ if (wait_intr_flag)
+ {
+ last_command_exit_value = 128 + sig;
+ wait_signal_received = sig;
+ SIGRETURN (0);
+ }
+
+ if (interrupt_immediately)
+ {
+ interrupt_immediately = 0;
+ last_command_exit_value = 128 + sig;
+ throw_to_top_level ();
+ }
+#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. */
+ else if (RL_ISSTATE (RL_STATE_SIGHANDLER))
+ bashline_set_event_hook ();
+#endif
+
+ SIGRETURN (0);
+}
+
+#if defined (SIGWINCH)
+sighandler
+sigwinch_sighandler (sig)
+ int sig;
+{
+#if defined (MUST_REINSTALL_SIGHANDLERS)
+ set_signal_handler (SIGWINCH, sigwinch_sighandler);
+#endif /* MUST_REINSTALL_SIGHANDLERS */
+ sigwinch_received = 1;
+ SIGRETURN (0);
+}
+#endif /* SIGWINCH */
+
+void
+set_sigwinch_handler ()
+{
+#if defined (SIGWINCH)
+ old_winch = set_signal_handler (SIGWINCH, sigwinch_sighandler);
+#endif
+}
+
+void
+unset_sigwinch_handler ()
+{
+#if defined (SIGWINCH)
+ set_signal_handler (SIGWINCH, old_winch);
+#endif
+}
+
+sighandler
+sigterm_sighandler (sig)
+ int sig;
+{
+ sigterm_received = 1; /* XXX - counter? */
+ SIGRETURN (0);
+}
+
+/* Signal functions used by the rest of the code. */
+#if !defined (HAVE_POSIX_SIGNALS)
+
+/* Perform OPERATION on NEWSET, perhaps leaving information in OLDSET. */
+sigprocmask (operation, newset, oldset)
+ int operation, *newset, *oldset;
+{
+ int old, new;
+
+ if (newset)
+ new = *newset;
+ else
+ new = 0;
+
+ switch (operation)
+ {
+ case SIG_BLOCK:
+ old = sigblock (new);
+ break;
+
+ case SIG_SETMASK:
+ old = sigsetmask (new);
+ break;
+
+ default:
+ internal_error (_("sigprocmask: %d: invalid operation"), operation);
+ }
+
+ if (oldset)
+ *oldset = old;
+}
+
+#else
+
+#if !defined (SA_INTERRUPT)
+# define SA_INTERRUPT 0
+#endif
+
+#if !defined (SA_RESTART)
+# define SA_RESTART 0
+#endif
+
+SigHandler *
+set_signal_handler (sig, handler)
+ int sig;
+ SigHandler *handler;
+{
+ struct sigaction act, oact;
+
+ act.sa_handler = handler;
+ act.sa_flags = 0;
+
+ /* XXX - bash-4.2 */
+ /* We don't want a child death to interrupt interruptible system calls, even
+ if we take the time to reap children */
+#if defined (SIGCHLD)
+ if (sig == SIGCHLD)
+ act.sa_flags |= SA_RESTART; /* XXX */
+#endif
+ /* Let's see if we can keep SIGWINCH from interrupting interruptible system
+ calls, like open(2)/read(2)/write(2) */
+#if defined (SIGWINCH)
+ if (sig == SIGWINCH)
+ act.sa_flags |= SA_RESTART; /* XXX */
+#endif
+ /* If we're installing a SIGTERM handler for interactive shells, we want
+ it to be as close to SIG_IGN as possible. */
+ if (sig == SIGTERM && handler == sigterm_sighandler)
+ act.sa_flags |= SA_RESTART; /* XXX */
+
+ sigemptyset (&act.sa_mask);
+ sigemptyset (&oact.sa_mask);
+ if (sigaction (sig, &act, &oact) == 0)
+ return (oact.sa_handler);
+ else
+ return (SIG_DFL);
+}
+#endif /* HAVE_POSIX_SIGNALS */