X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fposix_spawn.m4;h=acf122de17e9818d4f9ca8bf3fb82bc099923737;hb=175caaec9cd1aa171316be789c2a744aba22855a;hp=9cd5a661967ae2e3818da8caac853fc60f20c7ac;hpb=07c1f7b3d60a2d8433bddf1a85c33bc2ba4f59ff;p=gnulib.git

diff --git a/m4/posix_spawn.m4 b/m4/posix_spawn.m4
index 9cd5a6619..acf122de1 100644
--- a/m4/posix_spawn.m4
+++ b/m4/posix_spawn.m4
@@ -1,4 +1,4 @@
-# posix_spawn.m4 serial 1
+# posix_spawn.m4 serial 4
 dnl Copyright (C) 2008 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -36,15 +36,336 @@ AC_DEFUN([gl_POSIX_SPAWN_BODY],
   dnl AC_CHECK_FUNCS_ONCE([posix_spawnattr_getsigmask])
   dnl AC_CHECK_FUNCS_ONCE([posix_spawnattr_setsigmask])
   dnl AC_CHECK_FUNCS_ONCE([posix_spawnattr_destroy])
-  if test $ac_cv_func_posix_spawn != yes; then
+  if test $ac_cv_func_posix_spawn = yes; then
+    gl_POSIX_SPAWN_WORKS
+    case "$gl_cv_func_posix_spawn_works" in
+      *yes) ;;
+      *) REPLACE_POSIX_SPAWN=1 ;;
+    esac
+  else
     HAVE_POSIX_SPAWN=0
-    dnl For now, assume that if posix_spawn exists, it also works.
-    if false; then
-      REPLACE_POSIX_SPAWN=1
-    fi
   fi
 ])
 
+dnl Test whether posix_spawn actually works.
+dnl posix_spawn on AIX 5.3..6.1 has two bugs:
+dnl 1) When it fails to execute the program, the child process exits with
+dnl    exit() rather than _exit(), which causes the stdio buffers to be
+dnl    flushed. Reported by Rainer Tammer.
+dnl 2) The posix_spawn_file_actions_addopen function does not support file
+dnl    names that contain a '*'.
+dnl posix_spawn on AIX 5.3..6.1 has also a third bug: It does not work
+dnl when POSIX threads are used. But we don't test against this bug here.
+AC_DEFUN([gl_POSIX_SPAWN_WORKS],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether posix_spawn works], [gl_cv_func_posix_spawn_works],
+    [if test $cross_compiling = no; then
+       AC_LINK_IFELSE([AC_LANG_SOURCE([[
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <spawn.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+extern char **environ;
+
+#ifndef STDIN_FILENO
+# define STDIN_FILENO 0
+#endif
+#ifndef STDOUT_FILENO
+# define STDOUT_FILENO 1
+#endif
+#ifndef STDERR_FILENO
+# define STDERR_FILENO 2
+#endif
+
+#ifndef WTERMSIG
+# define WTERMSIG(x) ((x) & 0x7f)
+#endif
+#ifndef WIFEXITED
+# define WIFEXITED(x) (WTERMSIG (x) == 0)
+#endif
+#ifndef WEXITSTATUS
+# define WEXITSTATUS(x) (((x) >> 8) & 0xff)
+#endif
+
+#define CHILD_PROGRAM_FILENAME "/non/exist/ent"
+
+static int
+fd_safer (int fd)
+{
+  if (0 <= fd && fd <= 2)
+    {
+      int f = fd_safer (dup (fd));
+      int e = errno;
+      close (fd);
+      errno = e;
+      fd = f;
+    }
+
+  return fd;
+}
+
+int
+main ()
+{
+  char *argv[2] = { CHILD_PROGRAM_FILENAME, NULL };
+  int ofd[2];
+  sigset_t blocked_signals;
+  sigset_t fatal_signal_set;
+  posix_spawn_file_actions_t actions;
+  bool actions_allocated;
+  posix_spawnattr_t attrs;
+  bool attrs_allocated;
+  int err;
+  pid_t child;
+  int status;
+  int exitstatus;
+
+  setvbuf (stdout, NULL, _IOFBF, 0);
+  puts ("This should be seen only once.");
+  if (pipe (ofd) < 0 || (ofd[1] = fd_safer (ofd[1])) < 0)
+    {
+      perror ("cannot create pipe");
+      exit (1);
+    }
+  sigprocmask (SIG_SETMASK, NULL, &blocked_signals);
+  sigemptyset (&fatal_signal_set);
+  sigaddset (&fatal_signal_set, SIGINT);
+  sigaddset (&fatal_signal_set, SIGTERM);
+  sigaddset (&fatal_signal_set, SIGHUP);
+  sigaddset (&fatal_signal_set, SIGPIPE);
+  sigprocmask (SIG_BLOCK, &fatal_signal_set, NULL);
+  actions_allocated = false;
+  attrs_allocated = false;
+  if ((err = posix_spawn_file_actions_init (&actions)) != 0
+      || (actions_allocated = true,
+          (err = posix_spawn_file_actions_adddup2 (&actions, ofd[0], STDIN_FILENO)) != 0
+          || (err = posix_spawn_file_actions_addclose (&actions, ofd[0])) != 0
+          || (err = posix_spawn_file_actions_addclose (&actions, ofd[1])) != 0
+          || (err = posix_spawnattr_init (&attrs)) != 0
+          || (attrs_allocated = true,
+              (err = posix_spawnattr_setsigmask (&attrs, &blocked_signals)) != 0
+              || (err = posix_spawnattr_setflags (&attrs, POSIX_SPAWN_SETSIGMASK)) != 0)
+          || (err = posix_spawnp (&child, CHILD_PROGRAM_FILENAME, &actions, &attrs, argv, environ)) != 0))
+    {
+      if (actions_allocated)
+	posix_spawn_file_actions_destroy (&actions);
+      if (attrs_allocated)
+	posix_spawnattr_destroy (&attrs);
+      sigprocmask (SIG_UNBLOCK, &fatal_signal_set, NULL);
+      if (err == ENOENT)
+	return 0;
+      else
+	{
+	  errno = err;
+	  perror ("subprocess failed");
+	  exit (1);
+	}
+    }
+  posix_spawn_file_actions_destroy (&actions);
+  posix_spawnattr_destroy (&attrs);
+  sigprocmask (SIG_UNBLOCK, &fatal_signal_set, NULL);
+  close (ofd[0]);
+  close (ofd[1]);
+  status = 0;
+  while (waitpid (child, &status, 0) != child)
+    ;
+  if (!WIFEXITED (status))
+    {
+      fprintf (stderr, "subprocess terminated with unexpected wait status %d\n", status);
+      exit (1);
+    }
+  exitstatus = WEXITSTATUS (status);
+  if (exitstatus != 127)
+    {
+      fprintf (stderr, "subprocess terminated with unexpected exit status %d\n", exitstatus);
+      exit (1);
+    }
+  return 0;
+}
+]])],
+         [if test -s conftest$ac_exeext \
+             && ./conftest$ac_exeext > conftest.out \
+             && echo 'This should be seen only once.' > conftest.ok \
+             && cmp conftest.out conftest.ok > /dev/null; then
+            gl_cv_func_posix_spawn_works=yes
+          else
+            gl_cv_func_posix_spawn_works=no
+          fi],
+         [gl_cv_func_posix_spawn_works=no])
+       if test $gl_cv_func_posix_spawn_works = yes; then
+         AC_RUN_IFELSE([AC_LANG_SOURCE([[
+/* Test whether posix_spawn_file_actions_addopen supports filename arguments
+   that contain special characters such as '*'.  */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <spawn.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+extern char **environ;
+
+#ifndef STDIN_FILENO
+# define STDIN_FILENO 0
+#endif
+#ifndef STDOUT_FILENO
+# define STDOUT_FILENO 1
+#endif
+#ifndef STDERR_FILENO
+# define STDERR_FILENO 2
+#endif
+
+#ifndef WTERMSIG
+# define WTERMSIG(x) ((x) & 0x7f)
+#endif
+#ifndef WIFEXITED
+# define WIFEXITED(x) (WTERMSIG (x) == 0)
+#endif
+#ifndef WEXITSTATUS
+# define WEXITSTATUS(x) (((x) >> 8) & 0xff)
+#endif
+
+#define CHILD_PROGRAM_FILENAME "conftest"
+#define DATA_FILENAME "conftest%=*#?"
+
+static int
+parent_main (void)
+{
+  FILE *fp;
+  char *argv[3] = { CHILD_PROGRAM_FILENAME, "-child", NULL };
+  posix_spawn_file_actions_t actions;
+  bool actions_allocated;
+  int err;
+  pid_t child;
+  int status;
+  int exitstatus;
+
+  /* Create a data file with specific contents.  */
+  fp = fopen (DATA_FILENAME, "wb");
+  if (fp == NULL)
+    {
+      perror ("cannot create data file");
+      return 1;
+    }
+  fwrite ("Halle Potta", 1, 11, fp);
+  if (fflush (fp) || fclose (fp))
+    {
+      perror ("cannot prepare data file");
+      return 1;
+    }
+
+  /* Avoid reading from our stdin, as it could block.  */
+  freopen ("/dev/null", "rb", stdin);
+
+  /* Test whether posix_spawn_file_actions_addopen with this file name
+     actually works, but spawning a child that reads from this file.  */
+  actions_allocated = false;
+  if ((err = posix_spawn_file_actions_init (&actions)) != 0
+      || (actions_allocated = true,
+          (err = posix_spawn_file_actions_addopen (&actions, STDIN_FILENO, DATA_FILENAME, O_RDONLY, 0600)) != 0
+          || (err = posix_spawn (&child, CHILD_PROGRAM_FILENAME, &actions, NULL, argv, environ)) != 0))
+    {
+      if (actions_allocated)
+        posix_spawn_file_actions_destroy (&actions);
+      errno = err;
+      perror ("subprocess failed");
+      return 1;
+    }
+  posix_spawn_file_actions_destroy (&actions);
+  status = 0;
+  while (waitpid (child, &status, 0) != child)
+    ;
+  if (!WIFEXITED (status))
+    {
+      fprintf (stderr, "subprocess terminated with unexpected wait status %d\n", status);
+      return 1;
+    }
+  exitstatus = WEXITSTATUS (status);
+  if (exitstatus != 0)
+    {
+      fprintf (stderr, "subprocess terminated with unexpected exit status %d\n", exitstatus);
+      return 1;
+    }
+  return 0;
+}
+
+static int
+child_main (void)
+{
+  char buf[1024];
+
+  /* See if reading from STDIN_FILENO yields the expected contents.  */
+  if (fread (buf, 1, sizeof (buf), stdin) == 11
+      && memcmp (buf, "Halle Potta", 11) == 0)
+    return 0;
+  else
+    return 2;
+}
+
+static void
+cleanup_then_die (int sig)
+{
+  /* Clean up data file.  */
+  unlink (DATA_FILENAME);
+
+  /* Re-raise the signal and die from it.  */
+  signal (sig, SIG_DFL);
+  raise (sig);
+}
+
+int
+main (int argc, char *argv[])
+{
+  int exitstatus;
+
+  if (!(argc > 1 && strcmp (argv[1], "-child") == 0))
+    {
+      /* This is the parent process.  */
+      signal (SIGINT, cleanup_then_die);
+      signal (SIGTERM, cleanup_then_die);
+      #ifdef SIGHUP
+      signal (SIGHUP, cleanup_then_die);
+      #endif
+
+      exitstatus = parent_main ();
+    }
+  else
+    {
+      /* This is the child process.  */
+
+      exitstatus = child_main ();
+    }
+  unlink (DATA_FILENAME);
+  return exitstatus;
+}
+]])],
+           [],
+           [gl_cv_func_posix_spawn_works=no])
+       fi
+     else
+       case "$host_os" in
+         aix*) gl_cv_func_posix_spawn_works="guessing no";;
+         *)    gl_cv_func_posix_spawn_works="guessing yes";;
+       esac
+     fi
+    ])
+])
+
 AC_DEFUN([gl_POSIX_SPAWN_INTERNAL],
 [
   AC_LIBOBJ([spawni])