Fix PR 6376: restore more thread library state if execve fails,

including the scheduling timer, sigmask, fd nonblocking status, and
handling of the signals used by the thread library.

ok marc@, additional testing by ajacoutot@

3 files changed, 55 insertions, 46 deletions

diff --git a/lib/libpthread/uthread/pthread_private.h b/lib/libpthread/uthread/pthread_private.h
index 513ded4432d..4a7a1243b74 100644
--- a/lib/libpthread/uthread/pthread_private.h
+++ b/lib/libpthread/uthread/pthread_private.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pthread_private.h,v 1.74 2010/01/03 23:05:35 fgsch Exp $	*/
+/*	$OpenBSD: pthread_private.h,v 1.75 2010/07/13 03:10:29 guenther Exp $	*/
 /*
  * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>.
  * All rights reserved.
@@ -1132,6 +1132,7 @@ int     _thread_create(pthread_t *, const pthread_attr_t *,
 void    _dispatch_signal(int, struct sigcontext *);
 void    _dispatch_signals(struct sigcontext *);
 void    _thread_signal(pthread_t, int);
+void	_thread_nonblock_fds(void);
 int	_mutex_cv_lock(pthread_mutex_t *);
 int	_mutex_cv_unlock(pthread_mutex_t *);
 int	_mutex_reinit(pthread_mutex_t *);
diff --git a/lib/libpthread/uthread/uthread_execve.c b/lib/libpthread/uthread/uthread_execve.c
index 6abbcc4bb02..ba910646021 100644
--- a/lib/libpthread/uthread/uthread_execve.c
+++ b/lib/libpthread/uthread/uthread_execve.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uthread_execve.c,v 1.11 2010/06/27 03:14:28 guenther Exp $	*/
+/*	$OpenBSD: uthread_execve.c,v 1.12 2010/07/13 03:10:29 guenther Exp $	*/
 /*
  * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
  * All rights reserved.
@@ -46,16 +46,18 @@ execve(const char *name, char *const * argv, char *const * envp)
 	int		flags;
 	int             i;
 	int             ret;
+	int		err;
 	struct sigaction act;
-	struct sigaction oact;
 	struct itimerval itimer;
+	struct itimerval oitimer;
+	sigset_t	oset;
 
 	/* Disable the interval timer: */
 	itimer.it_interval.tv_sec  = 0;
 	itimer.it_interval.tv_usec = 0;
 	itimer.it_value.tv_sec     = 0;
 	itimer.it_value.tv_usec    = 0;
-	setitimer(_ITIMER_SCHED_TIMER, &itimer, NULL);
+	setitimer(_ITIMER_SCHED_TIMER, &itimer, &oitimer);
 
 	/*
 	 * Enter a loop to set all file descriptors to blocking
@@ -77,40 +79,42 @@ execve(const char *name, char *const * argv, char *const * envp)
 		}
 	}
 
-	/* Enter a loop to adopt the signal actions for the running thread: */
-	for (i = 1; i < NSIG; i++) {
-		/* Check for signals which cannot be caught: */
-		if (i == SIGKILL || i == SIGSTOP) {
-			/* Don't do anything with these signals. */
-		} else {
-			/* Check if ignoring this signal: */
-			if (_thread_sigact[i - 1].sa_handler == SIG_IGN) {
-				/* Continue to ignore this signal: */
-				act.sa_handler = SIG_IGN;
-			} else {
-				/* Use the default handler for this signal: */
-				act.sa_handler = SIG_DFL;
-			}
-
-			/* Copy the mask and flags for this signal: */
-			act.sa_mask = _thread_sigact[i - 1].sa_mask;
-			act.sa_flags = _thread_sigact[i - 1].sa_flags;
-
-			/* Ensure the scheduling signal is masked: */
-			sigaddset(&act.sa_mask, _SCHED_SIGNAL);
-
-			/* Change the signal action for the process: */
-			_thread_sys_sigaction(i, &act, &oact);
-		}
-	}
+#define RESET_SIGNAL(sig) \
+	(_thread_sigact[(sig) - 1].sa_handler == SIG_IGN && \
+	_thread_sys_sigaction((sig), &_thread_sigact[(sig) - 1], NULL) != 0)
+	
+	/* Reset the behavior for the signals that the library uses */
+	if (RESET_SIGNAL(_SCHED_SIGNAL) ||
+	    RESET_SIGNAL(SIGINFO) ||
+	    RESET_SIGNAL(SIGCHLD))
+		PANIC("Cannot reset signal handlers");
 
 	/* Set the signal mask: */
-	_thread_sys_sigprocmask(SIG_SETMASK, &curthread->sigmask, NULL);
+	_thread_sys_sigprocmask(SIG_SETMASK, &curthread->sigmask, &oset);
 
 	/* Execute the process: */
 	ret = _thread_sys_execve(name, argv, envp);
+	err = errno;
+
+	/* execve failed; try to restore the state the thread library needs */
+
+#define REINIT_SIGNAL(sig) \
+	(_thread_sigact[(sig) - 1].sa_handler == SIG_IGN && \
+	_thread_sys_sigaction((sig), &act, NULL) != 0)
+
+	_thread_sys_sigprocmask(SIG_SETMASK, &oset, NULL);
+	sigfillset(&act.sa_mask);
+	act.sa_handler = (void (*) (int)) _thread_sig_handler;
+	act.sa_flags = SA_SIGINFO;
+	if (REINIT_SIGNAL(_SCHED_SIGNAL) ||
+	    REINIT_SIGNAL(SIGINFO) ||
+	    REINIT_SIGNAL(SIGCHLD))
+		PANIC("Cannot reinitialize signal handlers");
+	_thread_nonblock_fds();
+	setitimer(_ITIMER_SCHED_TIMER, &oitimer, NULL);
 
 	/* Return the completion status: */
+	errno = err;
 	return (ret);
 }
 #endif
diff --git a/lib/libpthread/uthread/uthread_sig.c b/lib/libpthread/uthread/uthread_sig.c
index 6d54c04744b..16754dcfa16 100644
--- a/lib/libpthread/uthread/uthread_sig.c
+++ b/lib/libpthread/uthread/uthread_sig.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uthread_sig.c,v 1.25 2010/01/03 23:05:35 fgsch Exp $	*/
+/*	$OpenBSD: uthread_sig.c,v 1.26 2010/07/13 03:10:29 guenther Exp $	*/
 /*
  * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
  * All rights reserved.
@@ -161,6 +161,22 @@ _thread_clear_pending(int sig, pthread_t thread)
 		sigdelset(&thread->sigpend, sig);
 }
 
+void
+_thread_nonblock_fds(void)
+{
+	int	i;
+
+	/*
+	 * Go through the file list and set all files to non-blocking
+	 * again in case the child set some of them to block. Sigh.
+	 */
+	for (i = 0; i < _thread_max_fdtsize; i++)
+		if (_thread_fd_table[i] != NULL &&
+		    _thread_fd_table[i]->status_flags != NULL)
+			_thread_sys_fcntl(i, F_SETFL,
+			    (_thread_fd_table[i]->status_flags->flags & ~_FD_NOTSOCK) |
+			    O_NONBLOCK);
+}
 
 /*
  * Process the given signal.   Returns 1 if the signal may be dispatched,
@@ -171,7 +187,6 @@ int
 _thread_sig_handle(int sig, struct sigcontext * scp)
 {
 	struct pthread	*curthread = _get_curthread();
-	int		i;
 	pthread_t	pthread, pthread_next;
 
 	if (sig == SIGINFO)
@@ -179,19 +194,8 @@ _thread_sig_handle(int sig, struct sigcontext * scp)
 	else if (sig == _SCHED_SIGNAL)
 		; /* This shouldn't ever occur (should this panic?). */
 	else {
-		if (sig == SIGCHLD) {
-			/*
-			 * Go through the file list and set all files
-			 * to non-blocking again in case the child
-			 * set some of them to block. Sigh.
-			 */
-			for (i = 0; i < _thread_max_fdtsize; i++)
-				if (_thread_fd_table[i] != NULL &&
-				    _thread_fd_table[i]->status_flags != NULL)
-					_thread_sys_fcntl(i, F_SETFL,
-					    (_thread_fd_table[i]->status_flags->flags & ~_FD_NOTSOCK) |
-					    O_NONBLOCK);
-		}
+		if (sig == SIGCHLD)
+			_thread_nonblock_fds();
 
 		/*
 		 * If the handler is SIG_IGN the signal never happened.