newlib/libc/posix/posix_spawn.c - native_client/nacl-newlib - Git at Google

 /*-
  * Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */

 /*
 FUNCTION
 <<posix_spawn>>, <<posix_spawnp>>---spawn a process

 INDEX
 	posix_spawn
 INDEX
 	posix_spawnp

 ANSI_SYNOPSIS
 	#include <spawn.h>

 	int posix_spawn(pid_t *<[pid]>, const char *<[path]>,
 			const posix_spawn_file_actions_t *<[file_actions]>,
 			const posix_spawnattr_t *<[attrp]>,
 			char *const <[argv]>, char *const <[envp]>);
 	int posix_spawnp(pid_t *<[pid]>, const char *<[file]>,
 			const posix_spawn_file_actions_t *<[file_actions]>,
 			const posix_spawnattr_t *<[attrp]>,
 			char *const <[argv]>, char *const <[envp]>);

 DESCRIPTION
 Use <<posix_spawn>> and <<posix_spawnp>> to create a new child process
 from the specified process image file. <<argc>> is the argument count
 and <<argv>> is an array of argument strings passed to the new program.
 <<envp>> is an array of stings, which are passed as environment to the
 new program.

 The <<path>> argument to <<posix_spawn>> identifies the new process
 image file to execute. The <<file>> argument to <<posix_spawnp>> is
 used to construct a pathname that identifies the new process image
 file by duplicating the actions of the shell in searching for an
 executable file if the specified filename does not contain a `<</>>'
 character. The <<file>> is sought in the colon-separated list of
 directory pathnames specified in the <<PATH>> environment variable.

 The file descriptors remain open across <<posix_spawn>> and
 <<posix_spawnp>> except for those marked as close-on-exec. The open
 file descriptors in the child process can be modified by the spawn file
 actions object pointed to by <<file_actions>>.

 The spawn attributes object type pointed to by <<attrp>> argument
 may contain any of the attributes defined in <<spawn.h>>.

 RETURNS
 <<posix_spawn>> and <<posix_spawnp>> return the process ID of the newly
 spawned child process in the variable pointed by a non-NULL <<*<[pid]>>>
 argument and zero as the function return value upon successful
 completion. Otherwise, <<posix_spawn>> and <<posix_spawnp>> return an
 error number as the function return value to indicate the error; the
 value stored into the variable pointed to by a non-NULL <<*<[pid]>>>
 argument is unspecified.

 PORTABILITY
 POSIX.1-2008 requires <<posix_spawn>> and <<posix_spawnp>>.

 Supporting OS subroutines required: <<_close>>, <<dup2>>, <<_fcntl>>,
 <<_execve>>, <<execvpe>>, <<_exit>>, <<_open>>, <<sigaction>>,
 <<sigprocmask>>, <<waitpid>>, <<sched_setscheduler>>,
 <<sched_setparam>>, <<setegid>>, <<seteuid>>, <<setpgid>>, <<vfork>>.
 */

 #ifndef _NO_POSIX_SPAWN

 #include <sys/cdefs.h>

 #include <sys/signal.h>
 #include <sys/wait.h>
 #include <_syslist.h>

 #include <errno.h>
 #include <fcntl.h>
 #include <spawn.h>
 #include <signal.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>

 /* Only deal with a pointer to environ, to work around subtle bugs with shared
    libraries and/or small data systems where the user declares his own
    'environ'.  */
 static char ***p_environ = &environ;

 /*
  * Spawn routines
  */

 static int
 process_spawnattr(_CONST posix_spawnattr_t* sa)
 {
 	struct sigaction sigact = { .sa_flags = 0, .sa_handler = SIG_DFL };
 	int i;

 	/*
 	 * POSIX doesn't really describe in which order everything
 	 * should be set. We'll just set them in the order in which they
 	 * are mentioned.
 	 */

 	/* Set process group */
 	if (sa->sa_flags & POSIX_SPAWN_SETPGROUP) {
 		if (setpgid(0, sa->sa_pgroup) != 0)
 			return (errno);
 	}

 	/* Set scheduler policy */
 	if (sa->sa_flags & POSIX_SPAWN_SETSCHEDULER) {
 		if (sched_setscheduler(0, sa->sa_schedpolicy,
 		    &sa->sa_schedparam) != 0)
 			return (errno);
 	} else if (sa->sa_flags & POSIX_SPAWN_SETSCHEDPARAM) {
 		if (sched_setparam(0, &sa->sa_schedparam) != 0)
 			return (errno);
 	}

 	/* Reset user ID's */
 	if (sa->sa_flags & POSIX_SPAWN_RESETIDS) {
 		if (setegid(getgid()) != 0)
 			return (errno);
 		if (seteuid(getuid()) != 0)
 			return (errno);
 	}

 	/* Set signal masks/defaults */
 	if (sa->sa_flags & POSIX_SPAWN_SETSIGMASK) {
 		sigprocmask(SIG_SETMASK, &sa->sa_sigmask, NULL);
 	}

 	if (sa->sa_flags & POSIX_SPAWN_SETSIGDEF) {
 		for (i = 1; i < NSIG; i++) {
 			if (sigismember(&sa->sa_sigdefault, i))
 				if (sigaction(i, &sigact, NULL) != 0)
 					return (errno);
 		}
 	}

 	return (0);
 }

 static int
 process_file_actions_entry(posix_spawn_file_actions_entry_t *fae)
 {
 	int fd;

 	switch (fae->fae_action) {
 	case FAE_OPEN:
 		/* Perform an open(), make it use the right fd */
 		fd = _open(fae->fae_path, fae->fae_oflag, fae->fae_mode);
 		if (fd < 0)
 			return (errno);
 		if (fd != fae->fae_fildes) {
 			if (dup2(fd, fae->fae_fildes) == -1)
 				return (errno);
 			if (_close(fd) != 0) {
 				if (errno == EBADF)
 					return (EBADF);
 			}
 		}
 #ifdef HAVE_FCNTL
 		if (_fcntl(fae->fae_fildes, F_SETFD, 0) == -1)
 			return (errno);
 #endif /* HAVE_FCNTL */
 		break;
 	case FAE_DUP2:
 		/* Perform a dup2() */
 		if (dup2(fae->fae_fildes, fae->fae_newfildes) == -1)
 			return (errno);
 #ifdef HAVE_FCNTL
 		if (_fcntl(fae->fae_newfildes, F_SETFD, 0) == -1)
 			return (errno);
 #endif /* HAVE_FCNTL */
 		break;
 	case FAE_CLOSE:
 		/* Perform a close(), do not fail if already closed */
 		(void)_close(fae->fae_fildes);
 		break;
 	}
 	return (0);
 }

 static int
 process_file_actions(_CONST posix_spawn_file_actions_t* fa)
 {
 	posix_spawn_file_actions_entry_t *fae;
 	int error;

 	/* Replay all file descriptor modifications */
 	STAILQ_FOREACH(fae, &fa->fa_list, fae_list) {
 		error = process_file_actions_entry(fae);
 		if (error)
 			return (error);
 	}
 	return (0);
 }

 static int
 do_posix_spawn(pid_t *pid, _CONST char *path,
 	_CONST posix_spawn_file_actions_t *fa,
 	_CONST posix_spawnattr_t *sa,
 	char * _CONST argv[], char * _CONST envp[], int use_env_path)
 {
 	pid_t p;
 	volatile int error = 0;

 	p = vfork();
 	switch (p) {
 	case -1:
 		return (errno);
 	case 0:
 		if (sa != NULL) {
 			error = process_spawnattr(sa);
 			if (error)
 				_exit(127);
 		}
 		if (fa != NULL) {
 			error = process_file_actions(fa);
 			if (error)
 				_exit(127);
 		}
 		if (use_env_path)
 			execvpe(path, argv, envp != NULL ? envp : *p_environ);
 		else
 			_execve(path, argv, envp != NULL ? envp : *p_environ);
 		error = errno;
 		_exit(127);
 	default:
 		if (error != 0)
 			waitpid(p, NULL, WNOHANG);
 		else if (pid != NULL)
 			*pid = p;
 		return (error);
 	}
 }

 int
 _DEFUN(posix_spawn, (pid, path, fa, sa, argv, envp),
 	pid_t *pid _AND
 	_CONST char *path _AND
 	_CONST posix_spawn_file_actions_t *fa _AND
 	_CONST posix_spawnattr_t *sa _AND
 	char * _CONST argv[] _AND
 	char * _CONST envp[])
 {
 	return do_posix_spawn(pid, path, fa, sa, argv, envp, 0);
 }

 int
 _DEFUN(posix_spawnp, (pid, path, fa, sa, argv, envp),
 	pid_t *pid _AND
 	_CONST char *path _AND
 	_CONST posix_spawn_file_actions_t *fa _AND
 	_CONST posix_spawnattr_t *sa _AND
 	char * _CONST argv[] _AND
 	char * _CONST envp[])
 {
 	return do_posix_spawn(pid, path, fa, sa, argv, envp, 1);
 }

 #endif  /* !_NO_POSIX_SPAWN */
	/*-
	* Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org>
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	* SUCH DAMAGE.
	*/

	/*
	FUNCTION
	<<posix_spawn>>, <<posix_spawnp>>---spawn a process

	INDEX
	posix_spawn
	INDEX
	posix_spawnp

	ANSI_SYNOPSIS
	#include <spawn.h>

	int posix_spawn(pid_t <[pid]>, const char <[path]>,
	const posix_spawn_file_actions_t *<[file_actions]>,
	const posix_spawnattr_t *<[attrp]>,
	char const <[argv]>, char const <[envp]>);
	int posix_spawnp(pid_t <[pid]>, const char <[file]>,
	const posix_spawn_file_actions_t *<[file_actions]>,
	const posix_spawnattr_t *<[attrp]>,
	char const <[argv]>, char const <[envp]>);

	DESCRIPTION
	Use <<posix_spawn>> and <<posix_spawnp>> to create a new child process
	from the specified process image file. <<argc>> is the argument count
	and <<argv>> is an array of argument strings passed to the new program.
	<<envp>> is an array of stings, which are passed as environment to the
	new program.

	The <<path>> argument to <<posix_spawn>> identifies the new process
	image file to execute. The <<file>> argument to <<posix_spawnp>> is
	used to construct a pathname that identifies the new process image
	file by duplicating the actions of the shell in searching for an
	executable file if the specified filename does not contain a `<</>>'
	character. The <<file>> is sought in the colon-separated list of
	directory pathnames specified in the <<PATH>> environment variable.

	The file descriptors remain open across <<posix_spawn>> and
	<<posix_spawnp>> except for those marked as close-on-exec. The open
	file descriptors in the child process can be modified by the spawn file
	actions object pointed to by <<file_actions>>.

	The spawn attributes object type pointed to by <<attrp>> argument
	may contain any of the attributes defined in <<spawn.h>>.

	RETURNS
	<<posix_spawn>> and <<posix_spawnp>> return the process ID of the newly
	spawned child process in the variable pointed by a non-NULL <<*<[pid]>>>
	argument and zero as the function return value upon successful
	completion. Otherwise, <<posix_spawn>> and <<posix_spawnp>> return an
	error number as the function return value to indicate the error; the
	value stored into the variable pointed to by a non-NULL <<*<[pid]>>>
	argument is unspecified.

	PORTABILITY
	POSIX.1-2008 requires <<posix_spawn>> and <<posix_spawnp>>.

	Supporting OS subroutines required: <<_close>>, <<dup2>>, <<_fcntl>>,
	<<_execve>>, <<execvpe>>, <<_exit>>, <<_open>>, <<sigaction>>,
	<<sigprocmask>>, <<waitpid>>, <<sched_setscheduler>>,
	<<sched_setparam>>, <<setegid>>, <<seteuid>>, <<setpgid>>, <<vfork>>.
	*/

	#ifndef _NO_POSIX_SPAWN

	#include <sys/cdefs.h>

	#include <sys/signal.h>
	#include <sys/wait.h>
	#include <_syslist.h>

	#include <errno.h>
	#include <fcntl.h>
	#include <spawn.h>
	#include <signal.h>
	#include <stdlib.h>
	#include <string.h>
	#include <unistd.h>

	/* Only deal with a pointer to environ, to work around subtle bugs with shared
	libraries and/or small data systems where the user declares his own
	'environ'. */
	static char ***p_environ = &environ;

	/*
	* Spawn routines
	*/

	static int
	process_spawnattr(_CONST posix_spawnattr_t* sa)
	{
	struct sigaction sigact = { .sa_flags = 0, .sa_handler = SIG_DFL };
	int i;

	/*
	* POSIX doesn't really describe in which order everything
	* should be set. We'll just set them in the order in which they
	* are mentioned.
	*/

	/* Set process group */
	if (sa->sa_flags & POSIX_SPAWN_SETPGROUP) {
	if (setpgid(0, sa->sa_pgroup) != 0)
	return (errno);
	}

	/* Set scheduler policy */
	if (sa->sa_flags & POSIX_SPAWN_SETSCHEDULER) {
	if (sched_setscheduler(0, sa->sa_schedpolicy,
	&sa->sa_schedparam) != 0)
	return (errno);
	} else if (sa->sa_flags & POSIX_SPAWN_SETSCHEDPARAM) {
	if (sched_setparam(0, &sa->sa_schedparam) != 0)
	return (errno);
	}

	/* Reset user ID's */
	if (sa->sa_flags & POSIX_SPAWN_RESETIDS) {
	if (setegid(getgid()) != 0)
	return (errno);
	if (seteuid(getuid()) != 0)
	return (errno);
	}

	/* Set signal masks/defaults */
	if (sa->sa_flags & POSIX_SPAWN_SETSIGMASK) {
	sigprocmask(SIG_SETMASK, &sa->sa_sigmask, NULL);
	}

	if (sa->sa_flags & POSIX_SPAWN_SETSIGDEF) {
	for (i = 1; i < NSIG; i++) {
	if (sigismember(&sa->sa_sigdefault, i))
	if (sigaction(i, &sigact, NULL) != 0)
	return (errno);
	}
	}

	return (0);
	}

	static int
	process_file_actions_entry(posix_spawn_file_actions_entry_t *fae)
	{
	int fd;

	switch (fae->fae_action) {
	case FAE_OPEN:
	/* Perform an open(), make it use the right fd */
	fd = _open(fae->fae_path, fae->fae_oflag, fae->fae_mode);
	if (fd < 0)
	return (errno);
	if (fd != fae->fae_fildes) {
	if (dup2(fd, fae->fae_fildes) == -1)
	return (errno);
	if (_close(fd) != 0) {
	if (errno == EBADF)
	return (EBADF);
	}
	}
	#ifdef HAVE_FCNTL
	if (_fcntl(fae->fae_fildes, F_SETFD, 0) == -1)
	return (errno);
	#endif /* HAVE_FCNTL */
	break;
	case FAE_DUP2:
	/* Perform a dup2() */
	if (dup2(fae->fae_fildes, fae->fae_newfildes) == -1)
	return (errno);
	#ifdef HAVE_FCNTL
	if (_fcntl(fae->fae_newfildes, F_SETFD, 0) == -1)
	return (errno);
	#endif /* HAVE_FCNTL */
	break;
	case FAE_CLOSE:
	/* Perform a close(), do not fail if already closed */
	(void)_close(fae->fae_fildes);
	break;
	}
	return (0);
	}

	static int
	process_file_actions(_CONST posix_spawn_file_actions_t* fa)
	{
	posix_spawn_file_actions_entry_t *fae;
	int error;

	/* Replay all file descriptor modifications */
	STAILQ_FOREACH(fae, &fa->fa_list, fae_list) {
	error = process_file_actions_entry(fae);
	if (error)
	return (error);
	}
	return (0);
	}

	static int
	do_posix_spawn(pid_t pid, _CONST char path,
	_CONST posix_spawn_file_actions_t *fa,
	_CONST posix_spawnattr_t *sa,
	char * _CONST argv[], char * _CONST envp[], int use_env_path)
	{
	pid_t p;
	volatile int error = 0;

	p = vfork();
	switch (p) {
	case -1:
	return (errno);
	case 0:
	if (sa != NULL) {
	error = process_spawnattr(sa);
	if (error)
	_exit(127);
	}
	if (fa != NULL) {
	error = process_file_actions(fa);
	if (error)
	_exit(127);
	}
	if (use_env_path)
	execvpe(path, argv, envp != NULL ? envp : *p_environ);
	else
	_execve(path, argv, envp != NULL ? envp : *p_environ);
	error = errno;
	_exit(127);
	default:
	if (error != 0)
	waitpid(p, NULL, WNOHANG);
	else if (pid != NULL)
	*pid = p;
	return (error);
	}
	}

	int
	_DEFUN(posix_spawn, (pid, path, fa, sa, argv, envp),
	pid_t *pid _AND
	_CONST char *path _AND
	_CONST posix_spawn_file_actions_t *fa _AND
	_CONST posix_spawnattr_t *sa _AND
	char * _CONST argv[] _AND
	char * _CONST envp[])
	{
	return do_posix_spawn(pid, path, fa, sa, argv, envp, 0);
	}

	int
	_DEFUN(posix_spawnp, (pid, path, fa, sa, argv, envp),
	pid_t *pid _AND
	_CONST char *path _AND
	_CONST posix_spawn_file_actions_t *fa _AND
	_CONST posix_spawnattr_t *sa _AND
	char * _CONST argv[] _AND
	char * _CONST envp[])
	{
	return do_posix_spawn(pid, path, fa, sa, argv, envp, 1);
	}

	#endif /* !_NO_POSIX_SPAWN */