diff options
Diffstat (limited to 'newlib/libc/sys/linux/system.c')
| -rw-r--r-- | newlib/libc/sys/linux/system.c | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/newlib/libc/sys/linux/system.c b/newlib/libc/sys/linux/system.c new file mode 100644 index 000000000..f8edfbf63 --- /dev/null +++ b/newlib/libc/sys/linux/system.c @@ -0,0 +1,158 @@ +/* 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) |