Make sure SIGPIPE is reset in child processes

* process.c (create_process): Reset SIGPIPE handler in the child.
* callproc.c (Fcall_process): Likewise.  (Bug#5238)

3 files changed, 43 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 04b0a34d513..8ba7b61290e 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2011-02-12  Andreas Schwab  <schwab@linux-m68k.org>
+
+        * process.c (create_process): Reset SIGPIPE handler in the child.
+        * callproc.c (Fcall_process): Likewise.  (Bug#5238)
+
 2011-02-12  Eli Zaretskii  <eliz@gnu.org>
 
         * xdisp.c <this_line_min_pos>: New variable.
diff --git a/src/callproc.c b/src/callproc.c
index 925eefb4b02..27e8493bcf1 100644
--- a/src/callproc.c
+++ b/src/callproc.c
@@ -445,6 +445,11 @@ usage: (call-process PROGRAM &optional INFILE BUFFER DISPLAY &rest ARGS)  */)
     register char **save_environ = environ;
     register int fd1 = fd[1];
     int fd_error = fd1;
+#ifdef HAVE_WORKING_VFORK
+    sigset_t procmask;
+    sigset_t blocked;
+    struct sigaction sigpipe_action;
+#endif
 
 #if 0  /* Some systems don't have sigblock.  */
     mask = sigblock (sigmask (SIGCHLD));
@@ -525,6 +530,18 @@ usage: (call-process PROGRAM &optional INFILE BUFFER DISPLAY &rest ARGS)  */)
     pid = child_setup (filefd, fd1, fd_error, (char **) new_argv,
                        0, current_dir);
 #else  /* not WINDOWSNT */
+
+#ifdef HAVE_WORKING_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.  */
+    sigemptyset (&blocked);
+    sigaddset (&blocked, SIGPIPE);
+    sigaction (SIGPIPE, 0, &sigpipe_action);
+    sigprocmask (SIG_BLOCK, &blocked, &procmask);
+#endif
+
     BLOCK_INPUT;
 
     pid = vfork ();
@@ -541,11 +558,26 @@ usage: (call-process PROGRAM &optional INFILE BUFFER DISPLAY &rest ARGS)  */)
 #else
         setpgrp (pid, pid);
 #endif /* USG */
+
+        /* GTK causes us to ignore SIGPIPE, make sure it is restored
+           in the child.  */
+        signal (SIGPIPE, SIG_DFL);
+#ifdef HAVE_WORKING_VFORK
+        sigprocmask (SIG_SETMASK, &procmask, 0);
+#endif
+
         child_setup (filefd, fd1, fd_error, (char **) new_argv,
                      0, current_dir);
       }
 
     UNBLOCK_INPUT;
+
+#ifdef HAVE_WORKING_VFORK
+    /* Restore the signal state.  */
+    sigaction (SIGPIPE, &sigpipe_action, 0);
+    sigprocmask (SIG_SETMASK, &procmask, 0);
+#endif
+
 #endif /* not WINDOWSNT */
 
     /* The MSDOS case did this already.  */
diff --git a/src/process.c b/src/process.c
index 80e70e49f8e..d026b9d030b 100644
--- a/src/process.c
+++ b/src/process.c
@@ -1786,6 +1786,7 @@ create_process (Lisp_Object process, char **new_argv, Lisp_Object current_dir)
   sigset_t blocked;
   struct sigaction sigint_action;
   struct sigaction sigquit_action;
+  struct sigaction sigpipe_action;
 #ifdef AIX
   struct sigaction sighup_action;
 #endif
@@ -1898,6 +1899,7 @@ create_process (Lisp_Object process, char **new_argv, Lisp_Object current_dir)
      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);
+  sigaddset (&blocked, SIGPIPE);  sigaction (SIGPIPE, 0, &sigpipe_action);
 #ifdef AIX
   sigaddset (&blocked, SIGHUP );  sigaction (SIGHUP , 0, &sighup_action );
 #endif
@@ -2054,6 +2056,9 @@ create_process (Lisp_Object process, char **new_argv, Lisp_Object current_dir)
 
         signal (SIGINT, SIG_DFL);
         signal (SIGQUIT, SIG_DFL);
+        /* GTK causes us to ignore SIGPIPE, make sure it is restored
+           in the child.  */
+        signal (SIGPIPE, SIG_DFL);
 
         /* Stop blocking signals in the child.  */
         sigprocmask (SIG_SETMASK, &procmask, 0);
@@ -2142,6 +2147,7 @@ create_process (Lisp_Object process, char **new_argv, Lisp_Object current_dir)
   /* Restore the parent's signal handlers.  */
   sigaction (SIGINT, &sigint_action, 0);
   sigaction (SIGQUIT, &sigquit_action, 0);
+  sigaction (SIGPIPE, &sigpipe_action, 0);
 #ifdef AIX
   sigaction (SIGHUP, &sighup_action, 0);
 #endif