maint: remove all uses of vfork: use fork instead

Our use of vfork now provokes warnings from gcc-4.6.0.
Also, vfork is no longer even specified by POSIX.1-2008.
* src/diff3.c (read_diff): Change each use of vfork to "fork".
Remove #ifdef'd code.
* src/util.c (begin_output, finish_output): Likewise.
* src/sdiff.c (cleanup, main, edit): Likewise.
(handler_index_of_SIGPIPE): Remove now-unused definition.
* src/system.h: Don't include <vfork.h>.
(vfork): Remove definition.
* ms/config.site: Remove reference to vfork cache variable.

ms/config.site

@@ -76,4 +76,3 @@ ac_cv_prog_LN_S='cp -pf'
 # We have `fork', but it always fails.  Don't trust Autoconf to be
 # smart enough to detect that...
 ac_cv_func_fork=no
-ac_cv_func_vfork=no

src/diff3.c

@@ -1144,7 +1144,7 @@ read_diff (char const *filea,
   int werrno = 0;
   struct stat pipestat;
 
-#if HAVE_WORKING_FORK || HAVE_WORKING_VFORK
+#if HAVE_WORKING_FORK
 
   char const *argv[9];
   char const **ap;
@@ -1166,7 +1166,7 @@ read_diff (char const *filea,
   if (pipe (fds) != 0)
     perror_with_exit ("pipe");
 
-  pid = vfork ();
+  pid = fork ();
   if (pid == 0)
     {
       /* Child */
@@ -1255,7 +1255,7 @@ read_diff (char const *filea,
 
   *output_placement = diff_result;
 
-#if ! (HAVE_WORKING_FORK || HAVE_WORKING_VFORK)
+#if ! HAVE_WORKING_FORK
 
   wstatus = pclose (fpipe);
   if (wstatus == -1)

src/sdiff.c

@@ -50,7 +50,7 @@ static char const **diffargv;
 static char * volatile tmpname;
 static FILE *tmp;
 
-#if HAVE_WORKING_FORK || HAVE_WORKING_VFORK
+#if HAVE_WORKING_FORK
 static pid_t volatile diffpid;
 #endif
 
@@ -85,7 +85,6 @@ static int const sigs[] = {
 #endif
 #ifdef SIGPIPE
        SIGPIPE,
-# define handler_index_of_SIGPIPE (NUM_SIGS - 2)
 #endif
        SIGINT
 #define handler_index_of_SIGINT (NUM_SIGS - 1)
@@ -217,7 +216,7 @@ usage (void)
 static void
 cleanup (int signo __attribute__((unused)))
 {
-#if HAVE_WORKING_FORK || HAVE_WORKING_VFORK
+#if HAVE_WORKING_FORK
   if (0 < diffpid)
     kill (diffpid, SIGPIPE);
 #endif
@@ -595,7 +594,7 @@ main (int argc, char *argv[])
 
       trapsigs ();
 
-#if ! (HAVE_WORKING_FORK || HAVE_WORKING_VFORK)
+#if ! HAVE_WORKING_FORK
       {
 	size_t cmdsize = 1;
 	char *p, *command;
@@ -619,22 +618,11 @@ main (int argc, char *argv[])
 #else
       {
 	int diff_fds[2];
-# if HAVE_WORKING_VFORK
-	sigset_t procmask;
-	sigset_t blocked;
-# endif
 
 	if (pipe (diff_fds) != 0)
 	  perror_fatal ("pipe");
 
-# if HAVE_WORKING_VFORK
-	/* Block SIGINT and SIGPIPE.  */
-	sigemptyset (&blocked);
-	sigaddset (&blocked, SIGINT);
-	sigaddset (&blocked, SIGPIPE);
-	sigprocmask (SIG_BLOCK, &blocked, &procmask);
-# endif
-	diffpid = vfork ();
+	diffpid = fork ();
 	if (diffpid < 0)
 	  perror_fatal ("fork");
 	if (! diffpid)
@@ -646,10 +634,6 @@ main (int argc, char *argv[])
 	    if (initial_handler (handler_index_of_SIGINT) != SIG_IGN)
 	      signal_handler (SIGINT, SIG_IGN);
 	    signal_handler (SIGPIPE, SIG_DFL);
-# if HAVE_WORKING_VFORK
-	    /* Stop blocking SIGINT and SIGPIPE in the child.  */
-	    sigprocmask (SIG_SETMASK, &procmask, 0);
-# endif
 	    close (diff_fds[0]);
 	    if (diff_fds[1] != STDOUT_FILENO)
 	      {
@@ -661,19 +645,6 @@ main (int argc, char *argv[])
 	    _exit (errno == ENOENT ? 127 : 126);
 	  }
 
-# if HAVE_WORKING_VFORK
-	/* Restore the parent's SIGINT and SIGPIPE behavior.  */
-	if (initial_handler (handler_index_of_SIGINT) != SIG_IGN)
-	  signal_handler (SIGINT, catchsig);
-	if (initial_handler (handler_index_of_SIGPIPE) != SIG_IGN)
-	  signal_handler (SIGPIPE, catchsig);
-	else
-	  signal_handler (SIGPIPE, SIG_IGN);
-
-	/* Stop blocking SIGINT and SIGPIPE in the parent.  */
-	sigprocmask (SIG_SETMASK, &procmask, 0);
-# endif
-
 	close (diff_fds[1]);
 	diffout = fdopen (diff_fds[0], "r");
 	if (! diffout)
@@ -695,7 +666,7 @@ main (int argc, char *argv[])
 	int wstatus;
 	int werrno = 0;
 
-#if ! (HAVE_WORKING_FORK || HAVE_WORKING_VFORK)
+#if ! HAVE_WORKING_FORK
 	wstatus = pclose (diffout);
 	if (wstatus == -1)
 	  werrno = errno;
@@ -1042,7 +1013,7 @@ edit (struct line_filter *left, char const *lname, lin lline, lin llen,
 	      checksigs ();
 
 	      {
-#if ! (HAVE_WORKING_FORK || HAVE_WORKING_VFORK)
+#if ! HAVE_WORKING_FORK
 		char *command =
 		  xmalloc (shell_quote_length (editor_program)
 			   + 1 + strlen (tmpname) + 1);
@@ -1055,7 +1026,7 @@ edit (struct line_filter *left, char const *lname, lin lline, lin llen,
 #else
 		pid_t pid;
 
-		pid = vfork ();
+		pid = fork ();
 		if (pid == 0)
 		  {
 		    char const *argv[3];

src/system.h

@@ -115,15 +115,6 @@ int strcasecmp (char const *, char const *);
 #define MAX(a, b) ((a) >= (b) ? (a) : (b))
 
 #include <stdbool.h>
-
-#if HAVE_VFORK_H
-# include <vfork.h>
-#endif
-
-#if ! HAVE_WORKING_VFORK
-# define vfork fork
-#endif
-
 #include <intprops.h>
 #include "propername.h"
 

src/util.c

@@ -162,7 +162,7 @@ setup_output (char const *name0, char const *name1, bool recursive)
   outfile = 0;
 }
 
-#if HAVE_WORKING_FORK || HAVE_WORKING_VFORK
+#if HAVE_WORKING_FORK
 static pid_t pr_pid;
 #endif
 
@@ -192,13 +192,13 @@ begin_output (void)
 
       /* Make OUTFILE a pipe to a subsidiary `pr'.  */
       {
-#if HAVE_WORKING_FORK || HAVE_WORKING_VFORK
+#if HAVE_WORKING_FORK
 	int pipes[2];
 
 	if (pipe (pipes) != 0)
 	  pfatal_with_name ("pipe");
 
-	pr_pid = vfork ();
+	pr_pid = fork ();
 	if (pr_pid < 0)
 	  pfatal_with_name ("fork");
 
@@ -282,7 +282,7 @@ finish_output (void)
       int werrno = 0;
       if (ferror (outfile))
 	fatal ("write failed");
-#if ! (HAVE_WORKING_FORK || HAVE_WORKING_VFORK)
+#if ! HAVE_WORKING_FORK
       wstatus = pclose (outfile);
       if (wstatus == -1)
 	werrno = errno;