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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.18.0/] [newlib/] [libc/] [sys/] [linux/] [system.c] - Rev 207
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/* Copyright (C) 1991-1999, 2000 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 Lesser General Public License as published by the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ #include <stddef.h> #include <stdlib.h> #include <unistd.h> #include <sys/wait.h> #include <signal.h> #include <sys/types.h> #include <errno.h> #include <machine/weakalias.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 __libc_system (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) /* Check that we have a command processor available. It might not be available after a chroot(), for example. */ return __libc_system ("exit 0") == 0; 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 = fork (); 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 && errno != EINTR) { status = -1; break; } /* Note that pid cannot be <= -1 and therefore the loop continues when wait returned with EINTR. */ } while (child != pid); #else int n; do n = waitpid (pid, &status, 0); while (n == -1 && errno == EINTR); if (n != 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; } weak_alias (__libc_system, system)