-# posix_spawn.m4 serial 1
+# posix_spawn.m4 serial 2
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,
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 a bug: When it fails to execute the
+dnl program, the child process exits with exit() rather than _exit(),
+dnl which causes the stdio buffers to be flushed. Reported by Rainer Tammer.
+dnl posix_spawn on AIX 5.3..6.1 has also a second 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_PROGRAM([[
+#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 WCOREDUMP
+# define WCOREDUMP(x) ((x) & 0x80)
+#endif
+#ifndef WEXITSTATUS
+# define WEXITSTATUS(x) (((x) >> 8) & 0xff)
+#endif
+#ifndef WIFSIGNALED
+# define WIFSIGNALED(x) (WTERMSIG (x) != 0 && WTERMSIG(x) != 0x7f)
+#endif
+#ifndef WIFEXITED
+# define WIFEXITED(x) (WTERMSIG (x) == 0)
+#endif
+#ifndef WIFSTOPPED
+# define WIFSTOPPED(x) (WTERMSIG (x) == 0x7f)
+#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;
+}
+]],
+dnl Now comes the main() function.
+[[
+ 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);
+ 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);
+ }
+]])],
+ [if test -s conftest$ac_exeext \
+ && ./conftest$ac_exeext > conftest.out \
+ && echo 'This should be seen only once.' > conftest.ok \
+ && cmp conftest.out conftest.ok > /dev/null; then
+ gl_cv_func_posix_spawn_works=yes
+ else
+ gl_cv_func_posix_spawn_works=no
+ fi],
+ [gl_cv_func_posix_spawn_works=no])
+ else
+ case "$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])
projects / gnulib.git / commitdiff