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(create_process): Use Posix signal handling to

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block signals, if available.  If HAVE_VFORK, save and restore
signal handlers that the child might change, since in many
systems (e.g. Solaris 2.4) if the child changes the signal
handlers this munges the parent's handler.
This commit is contained in:
Karl Heuer 1995-12-13 01:52:07 +00:00
parent 3ec89604c4
commit 0dc70c33a0
1 changed files with 50 additions and 3 deletions
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53
src/process.c
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@ -1197,9 +1197,19 @@ create_process (process, new_argv, current_dir)
{
int pid, inchannel, outchannel;
int sv[2];
#ifdef POSIX_SIGNALS
sigset_t procmask;
sigset_t blocked;
struct sigaction sigint_action;
struct sigaction sigquit_action;
#ifdef AIX
struct sigaction sighup_action;
#endif
#else /* !POSIX_SIGNALS */
#ifdef SIGCHLD
SIGTYPE (*sigchld)();
#endif
#endif /* !POSIX_SIGNALS */
/* Use volatile to protect variables from being clobbered by longjmp. */
volatile int forkin, forkout;
volatile int pty_flag = 0;
@ -1298,6 +1308,24 @@ create_process (process, new_argv, current_dir)
/* Delay interrupts until we have a chance to store
the new fork's pid in its process structure */
#ifdef POSIX_SIGNALS
sigemptyset (&blocked);
#ifdef SIGCHLD
sigaddset (&blocked, SIGCHLD);
#endif
#ifdef HAVE_VFORK
/* On many hosts (e.g. Solaris 2.4), if a vforked child calls `signal',
this sets the parent's signal handlers as well as the child's.
So delay all interrupts whose handlers the child might munge,
and record the current handlers so they can be restored later. */
sigaddset (&blocked, SIGINT ); sigaction (SIGINT , 0, &sigint_action );
sigaddset (&blocked, SIGQUIT); sigaction (SIGQUIT, 0, &sigquit_action);
#ifdef AIX
sigaddset (&blocked, SIGHUP ); sigaction (SIGHUP , 0, &sighup_action );
#endif
#endif /* HAVE_VFORK */
sigprocmask (SIG_BLOCK, &blocked, &procmask);
#else /* !POSIX_SIGNALS */
#ifdef SIGCHLD
#ifdef BSD4_1
sighold (SIGCHLD);
@ -1312,6 +1340,7 @@ create_process (process, new_argv, current_dir)
#endif /* ordinary USG */
#endif /* not BSD4_1 */
#endif /* SIGCHLD */
#endif /* !POSIX_SIGNALS */
FD_SET (inchannel, &input_wait_mask);
FD_SET (inchannel, &non_keyboard_wait_mask);
@ -1455,6 +1484,13 @@ create_process (process, new_argv, current_dir)
#endif
#endif /* HAVE_PTYS */
signal (SIGINT, SIG_DFL);
signal (SIGQUIT, SIG_DFL);
/* Stop blocking signals in the child. */
#ifdef POSIX_SIGNALS
sigprocmask (SIG_SETMASK, &procmask, 0);
#else /* !POSIX_SIGNALS */
#ifdef SIGCHLD
#ifdef BSD4_1
sigrelse (SIGCHLD);
@ -1468,9 +1504,7 @@ create_process (process, new_argv, current_dir)
#endif /* ordinary USG */
#endif /* not BSD4_1 */
#endif /* SIGCHLD */
signal (SIGINT, SIG_DFL);
signal (SIGQUIT, SIG_DFL);
#endif /* !POSIX_SIGNALS */
if (pty_flag)
child_setup_tty (xforkout);
@ -1521,6 +1555,18 @@ create_process (process, new_argv, current_dir)
#endif
XPROCESS (process)->tty_name = Qnil;
#ifdef POSIX_SIGNALS
#ifdef HAVE_VFORK
/* Restore the parent's signal handlers. */
sigaction (SIGINT, &sigint_action, 0);
sigaction (SIGQUIT, &sigquit_action, 0);
#ifdef AIX
sigaction (SIGHUP, &sighup_action, 0);
#endif
#endif /* HAVE_VFORK */
/* Stop blocking signals in the parent. */
sigprocmask (SIG_SETMASK, &procmask, 0);
#else /* !POSIX_SIGNALS */
#ifdef SIGCHLD
#ifdef BSD4_1
sigrelse (SIGCHLD);
@ -1538,6 +1584,7 @@ create_process (process, new_argv, current_dir)
#endif /* ordinary USG */
#endif /* not BSD4_1 */
#endif /* SIGCHLD */
#endif /* !POSIX_SIGNALS */
}
#endif /* not VMS */