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authorRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
committerRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
commit28f540f45bbacd939bfd07f213bcad2bf730b1bf (patch)
tree15f07c4c43d635959c6afee96bde71fb1b3614ee /sysdeps/posix/system.c
downloadglibc-28f540f45bbacd939bfd07f213bcad2bf730b1bf.tar.gz
initial import
Diffstat (limited to 'sysdeps/posix/system.c')
-rw-r--r--sysdeps/posix/system.c145
1 files changed, 145 insertions, 0 deletions
diff --git a/sysdeps/posix/system.c b/sysdeps/posix/system.c
new file mode 100644
index 0000000000..69b004bb41
--- /dev/null
+++ b/sysdeps/posix/system.c
@@ -0,0 +1,145 @@
+/* Copyright (C) 1991, 1992, 1994 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C Library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB. If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA. */
+
+#include <ansidecl.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/wait.h>
+#include <signal.h>
+#include <sys/types.h>
+
+
+#ifndef HAVE_GNU_LD
+#define __environ environ
+#endif
+
+#define SHELL_PATH "/bin/sh" /* Path of the shell. */
+#define SHELL_NAME "sh" /* Name to give it. */
+
+/* Execute LINE as a shell command, returning its status. */
+int
+DEFUN(system, (line), register CONST char *line)
+{
+ int status, save;
+ pid_t pid;
+ struct sigaction sa, intr, quit;
+#ifndef WAITPID_CANNOT_BLOCK_SIGCHLD
+ sigset_t block, omask;
+#endif
+
+ if (line == NULL)
+ return 1;
+
+ sa.sa_handler = SIG_IGN;
+ sa.sa_flags = 0;
+ __sigemptyset (&sa.sa_mask);
+
+ if (__sigaction (SIGINT, &sa, &intr) < 0)
+ return -1;
+ if (__sigaction (SIGQUIT, &sa, &quit) < 0)
+ {
+ save = errno;
+ (void) __sigaction (SIGINT, &intr, (struct sigaction *) NULL);
+ errno = save;
+ return -1;
+ }
+
+#ifndef WAITPID_CANNOT_BLOCK_SIGCHLD
+
+/* SCO 3.2v4 has a bug where `waitpid' will never return if SIGCHLD is
+ blocked. This makes it impossible for `system' to be implemented in
+ compliance with POSIX.2-1992. They have acknowledged that this is a bug
+ but I have not seen nor heard of any forthcoming fix. */
+
+ __sigemptyset (&block);
+ __sigaddset (&block, SIGCHLD);
+ save = errno;
+ if (__sigprocmask (SIG_BLOCK, &block, &omask) < 0)
+ {
+ if (errno == ENOSYS)
+ errno = save;
+ else
+ {
+ save = errno;
+ (void) __sigaction (SIGINT, &intr, (struct sigaction *) NULL);
+ (void) __sigaction (SIGQUIT, &quit, (struct sigaction *) NULL);
+ errno = save;
+ return -1;
+ }
+ }
+#define UNBLOCK __sigprocmask (SIG_SETMASK, &omask, (sigset_t *) NULL)
+#else
+#define UNBLOCK 0
+#endif
+
+ pid = __vfork ();
+ if (pid == (pid_t) 0)
+ {
+ /* Child side. */
+ CONST char *new_argv[4];
+ new_argv[0] = SHELL_NAME;
+ new_argv[1] = "-c";
+ new_argv[2] = line;
+ new_argv[3] = NULL;
+
+ /* Restore the signals. */
+ (void) __sigaction (SIGINT, &intr, (struct sigaction *) NULL);
+ (void) __sigaction (SIGQUIT, &quit, (struct sigaction *) NULL);
+ (void) UNBLOCK;
+
+ /* Exec the shell. */
+ (void) __execve (SHELL_PATH, (char *CONST *) new_argv, __environ);
+ _exit (127);
+ }
+ else if (pid < (pid_t) 0)
+ /* The fork failed. */
+ status = -1;
+ else
+ /* Parent side. */
+#ifdef NO_WAITPID
+ {
+ pid_t child;
+ do
+ {
+ child = __wait (&status);
+ if (child <= -1)
+ {
+ status = -1;
+ break;
+ }
+ } while (child != pid);
+ }
+#else
+ if (__waitpid (pid, &status, 0) != pid)
+ status = -1;
+#endif
+
+ save = errno;
+ if ((__sigaction (SIGINT, &intr, (struct sigaction *) NULL) |
+ __sigaction (SIGQUIT, &quit, (struct sigaction *) NULL) |
+ UNBLOCK) != 0)
+ {
+ if (errno == ENOSYS)
+ errno = save;
+ else
+ return -1;
+ }
+
+ return status;
+}