Remove no-longer-needed Solaris 2.4 vfork bug workaround.

The workaround was for improving performance on Solaris 2.4, but
is getting in the way now.  Emacs will still work if someone is
still running Solaris 2.4 in a museum somewhere; Sun dropped
support for Solaris 2.4 in 2003.
* configure.ac (ac_cv_func_vfork_works): Default to 'no' on
Solaris 2.4, so that AC_FUNC_VFORK doesn't think vfork works.
* src/callproc.c (Fcall_process) [HAVE_WORKING_VFORK]:
* src/process.c (create_process) [HAVE_WORKING_VFORK]:
Omit now-unnecessary workaround for the Solaris 2.4 vfork bug,
since Emacs no longer uses vfork on that platform.

5 files changed, 34 insertions, 56 deletions

diff --git a/ChangeLog b/ChangeLog
index 5edcd767b27..7b9da902551 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2012-09-17  Paul Eggert  <eggert@cs.ucla.edu>
+
+	Remove no-longer-needed Solaris 2.4 vfork bug workaround.
+	* configure.ac (ac_cv_func_vfork_works): Default to 'no' on
+	Solaris 2.4, so that AC_FUNC_VFORK doesn't think vfork works.
+
 2012-09-17  Glenn Morris  <rgm@gnu.org>
 
 	* configure.ac (copyright): New output variable.
diff --git a/configure.ac b/configure.ac
index d09d22bcbbd..d0cbabf3d3d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3155,6 +3155,14 @@ else
   AC_MSG_RESULT(no)
 fi
 
+dnl Check for a Solaris 2.4 vfork bug that Autoconf misses (through 2.69).
+dnl This can be removed once we assume Autoconf 2.70.
+case $canonical in
+  *-solaris2.4 | *-solaris2.4.*)
+    dnl Disable the Autoconf-generated vfork test.
+    : ${ac_cv_func_vfork_works=no};;
+esac
+
 AC_FUNC_FORK
 
 AC_CHECK_FUNCS(snprintf)
diff --git a/src/ChangeLog b/src/ChangeLog
index 3c0799d14b3..daabdd7613e 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,15 @@
+2012-09-17  Paul Eggert  <eggert@cs.ucla.edu>
+
+	Remove no-longer-needed Solaris 2.4 vfork bug workaround.
+	The workaround was for improving performance on Solaris 2.4, but
+	is getting in the way now.  Emacs will still work if someone is
+	still running Solaris 2.4 in a museum somewhere; Sun dropped
+	support for Solaris 2.4 in 2003.
+	* callproc.c (Fcall_process) [HAVE_WORKING_VFORK]:
+	* process.c (create_process) [HAVE_WORKING_VFORK]:
+	Omit now-unnecessary workaround for the Solaris 2.4 vfork bug,
+	since Emacs no longer uses vfork on that platform.
+
 2012-09-17  Glenn Morris  <rgm@gnu.org>
 
 	* emacs.c: Use COPYRIGHT.
diff --git a/src/callproc.c b/src/callproc.c
index 9171337ee76..2604d295f3e 100644
--- a/src/callproc.c
+++ b/src/callproc.c
@@ -496,11 +496,6 @@ 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 (fd_output >= 0)
       fd1 = fd_output;
@@ -587,17 +582,6 @@ usage: (call-process PROGRAM &optional INFILE BUFFER DISPLAY &rest ARGS)  */)
 		       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);
-    pthread_sigmask (SIG_BLOCK, &blocked, &procmask);
-#endif
-
     BLOCK_INPUT;
 
     /* vfork, and prevent local vars from being clobbered by the vfork.  */
@@ -645,9 +629,6 @@ usage: (call-process PROGRAM &optional INFILE BUFFER DISPLAY &rest ARGS)  */)
 	/* GConf causes us to ignore SIGPIPE, make sure it is restored
 	   in the child.  */
 	signal (SIGPIPE, SIG_DFL);
-#ifdef HAVE_WORKING_VFORK
-	pthread_sigmask (SIG_SETMASK, &procmask, 0);
-#endif
 
 	child_setup (filefd, fd1, fd_error, (char **) new_argv,
 		     0, current_dir);
@@ -655,12 +636,6 @@ usage: (call-process PROGRAM &optional INFILE BUFFER DISPLAY &rest ARGS)  */)
 
     UNBLOCK_INPUT;
 
-#ifdef HAVE_WORKING_VFORK
-    /* Restore the signal state.  */
-    sigaction (SIGPIPE, &sigpipe_action, 0);
-    pthread_sigmask (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 a371dece250..c654369627d 100644
--- a/src/process.c
+++ b/src/process.c
@@ -1609,14 +1609,10 @@ create_process (Lisp_Object process, char **new_argv, Lisp_Object current_dir)
 #if !defined (WINDOWSNT) && defined (FD_CLOEXEC)
   int wait_child_setup[2];
 #endif
+#ifdef SIGCHLD
   sigset_t blocked, procmask;
-  struct sigaction sigint_action;
-  struct sigaction sigquit_action;
-  struct sigaction sigpipe_action;
-#ifdef AIX
-  struct sigaction sighup_action;
 #endif
-  /* Use volatile to protect variables from being clobbered by longjmp.  */
+  /* Use volatile to protect variables from being clobbered by vfork.  */
   volatile int forkin, forkout;
   volatile int pty_flag = 0;
 
@@ -1708,25 +1704,13 @@ create_process (Lisp_Object process, char **new_argv, Lisp_Object current_dir)
   XPROCESS (process)->pty_flag = pty_flag;
   pset_status (XPROCESS (process), Qrun);
 
+#ifdef SIGCHLD
   /* Delay interrupts until we have a chance to store
      the new fork's pid in its process structure */
   sigemptyset (&blocked);
-#ifdef SIGCHLD
   sigaddset (&blocked, SIGCHLD);
-#endif
-#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.  */
-  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
-#endif /* HAVE_WORKING_VFORK */
   pthread_sigmask (SIG_BLOCK, &blocked, &procmask);
+#endif
 
   FD_SET (inchannel, &input_wait_mask);
   FD_SET (inchannel, &non_keyboard_wait_mask);
@@ -1879,8 +1863,10 @@ create_process (Lisp_Object process, char **new_argv, Lisp_Object current_dir)
 	   in the child.  */
 	signal (SIGPIPE, SIG_DFL);
 
+#ifdef SIGCHLD
 	/* Stop blocking signals in the child.  */
 	pthread_sigmask (SIG_SETMASK, &procmask, 0);
+#endif
 
 	if (pty_flag)
 	  child_setup_tty (xforkout);
@@ -1959,19 +1945,10 @@ create_process (Lisp_Object process, char **new_argv, Lisp_Object current_dir)
 #endif
     }
 
-  /* Restore the signal state whether vfork succeeded or not.
-     (We will signal an error, below, if it failed.)  */
-#ifdef HAVE_WORKING_VFORK
-  /* 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
-#endif /* HAVE_WORKING_VFORK */
+#ifdef SIGCHLD
   /* Stop blocking signals in the parent.  */
   pthread_sigmask (SIG_SETMASK, &procmask, 0);
+#endif
 
   /* Now generate the error if vfork failed.  */
   if (pid < 0)