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@

diff --git a/lib/libpthread/uthread/pthread_private.h b/lib/libpthread/uthread/pthread_private.h
index 513ded4..4a7a124 100644 (file)
--- 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 6abbcc4..ba91064 100644 (file)
--- 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 6d54c04..16754dc 100644 (file)
--- 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.