Implement execvpe(3) and posix_spawn(3) and family. Based on

FreeBSD's implementation via Frank Denis, with various cleanups and
tweaks by me.

ok deraadt@, guenther@; discussions and tweaks from many others
jmc@ promises to help me further with the man pages in tree

1 files changed, 468 insertions, 0 deletions

diff --git a/lib/libc/gen/posix_spawn.c b/lib/libc/gen/posix_spawn.c
new file mode 100644
index 00000000000..cf1fadb1ef0
--- /dev/null
+++ b/lib/libc/gen/posix_spawn.c
@@ -0,0 +1,468 @@
+/*	$OpenBSD: posix_spawn.c,v 1.1 2012/03/21 23:20:35 matthew Exp $	*/
+/*-
+ * 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.
+ */
+
+#include <sys/cdefs.h>
+
+#include "namespace.h"
+#include <sys/queue.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <sched.h>
+#include <spawn.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+extern char **environ;
+
+struct __posix_spawnattr {
+	short			sa_flags;
+	pid_t			sa_pgroup;
+	struct sched_param	sa_schedparam;
+	int			sa_schedpolicy;
+	sigset_t		sa_sigdefault;
+	sigset_t		sa_sigmask;
+};
+
+struct __posix_spawn_file_actions {
+	SIMPLEQ_HEAD(, __posix_spawn_file_actions_entry) fa_list;
+};
+
+typedef struct __posix_spawn_file_actions_entry {
+	SIMPLEQ_ENTRY(__posix_spawn_file_actions_entry) fae_list;
+	enum { FAE_OPEN, FAE_DUP2, FAE_CLOSE } fae_action;
+
+	int fae_fildes;
+	union {
+		struct {
+			char *path;
+#define fae_path	fae_data.open.path
+			int oflag;
+#define fae_oflag	fae_data.open.oflag
+			mode_t mode;
+#define fae_mode	fae_data.open.mode
+		} open;
+		struct {
+			int newfildes;
+#define fae_newfildes	fae_data.dup2.newfildes
+		} dup2;
+	} fae_data;
+} posix_spawn_file_actions_entry_t;
+
+/*
+ * 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);
+	}
+
+#if 0 /* NOT IMPLEMENTED */
+	/* 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);
+	}
+#endif
+
+	/* 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);
+			}
+		}
+		break;
+	case FAE_DUP2:
+		/* Perform a dup2() */
+		if (dup2(fae->fae_fildes, fae->fae_newfildes) == -1)
+			return (errno);
+		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 */
+	SIMPLEQ_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;
+	
+	p = fork();
+	switch (p) {
+	case -1:
+		return (errno);
+	case 0: {
+		int error;
+		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 : environ);
+		else
+			execve(path, argv, envp != NULL ? envp : environ);
+		_exit(127);
+	}
+	default:
+		if (pid != NULL)
+			*pid = p;
+		return (0);
+	}
+}
+
+int
+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[])
+{
+	return do_posix_spawn(pid, path, fa, sa, argv, envp, 0);
+}
+
+int
+posix_spawnp(pid_t *pid, const char *path,
+    const posix_spawn_file_actions_t *fa,
+    const posix_spawnattr_t *sa,
+    char *const argv[], char *const envp[])
+{
+	return do_posix_spawn(pid, path, fa, sa, argv, envp, 1);
+}
+
+/*
+ * File descriptor actions
+ */
+
+int
+posix_spawn_file_actions_init(posix_spawn_file_actions_t *ret)
+{
+	posix_spawn_file_actions_t fa;
+
+	fa = malloc(sizeof(struct __posix_spawn_file_actions));
+	if (fa == NULL)
+		return (errno);
+
+	SIMPLEQ_INIT(&fa->fa_list);
+	*ret = fa;
+	return (0);
+}
+
+int
+posix_spawn_file_actions_destroy(posix_spawn_file_actions_t *fa)
+{
+	posix_spawn_file_actions_entry_t *fae;
+
+	while ((fae = SIMPLEQ_FIRST(&(*fa)->fa_list)) != NULL) {
+		/* Remove file action entry from the queue */
+		SIMPLEQ_REMOVE_HEAD(&(*fa)->fa_list, fae_list);
+
+		/* Deallocate file action entry */
+		if (fae->fae_action == FAE_OPEN)
+			free(fae->fae_path);
+		free(fae);
+	}
+
+	free(*fa);
+	return (0);
+}
+
+int
+posix_spawn_file_actions_addopen(posix_spawn_file_actions_t *__restrict fa,
+    int fildes, const char *__restrict path, int oflag, mode_t mode)
+{
+	posix_spawn_file_actions_entry_t *fae;
+	int error;
+
+	if (fildes < 0)
+		return (EBADF);
+
+	/* Allocate object */
+	fae = malloc(sizeof(posix_spawn_file_actions_entry_t));
+	if (fae == NULL)
+		return (errno);
+
+	/* Set values and store in queue */
+	fae->fae_action = FAE_OPEN;
+	fae->fae_path = strdup(path);
+	if (fae->fae_path == NULL) {
+		error = errno;
+		free(fae);
+		return (error);
+	}
+	fae->fae_fildes = fildes;
+	fae->fae_oflag = oflag;
+	fae->fae_mode = mode;
+
+	SIMPLEQ_INSERT_TAIL(&(*fa)->fa_list, fae, fae_list);
+	return (0);
+}
+
+int
+posix_spawn_file_actions_adddup2(posix_spawn_file_actions_t *fa,
+    int fildes, int newfildes)
+{
+	posix_spawn_file_actions_entry_t *fae;
+
+	if (fildes < 0 || newfildes < 0)
+		return (EBADF);
+
+	/* Allocate object */
+	fae = malloc(sizeof(posix_spawn_file_actions_entry_t));
+	if (fae == NULL)
+		return (errno);
+
+	/* Set values and store in queue */
+	fae->fae_action = FAE_DUP2;
+	fae->fae_fildes = fildes;
+	fae->fae_newfildes = newfildes;
+
+	SIMPLEQ_INSERT_TAIL(&(*fa)->fa_list, fae, fae_list);
+	return (0);
+}
+
+int
+posix_spawn_file_actions_addclose(posix_spawn_file_actions_t *fa,
+    int fildes)
+{
+	posix_spawn_file_actions_entry_t *fae;
+
+	if (fildes < 0)
+		return (EBADF);
+
+	/* Allocate object */
+	fae = malloc(sizeof(posix_spawn_file_actions_entry_t));
+	if (fae == NULL)
+		return (errno);
+
+	/* Set values and store in queue */
+	fae->fae_action = FAE_CLOSE;
+	fae->fae_fildes = fildes;
+
+	SIMPLEQ_INSERT_TAIL(&(*fa)->fa_list, fae, fae_list);
+	return (0);
+}
+
+/*
+ * Spawn attributes
+ */
+
+int
+posix_spawnattr_init(posix_spawnattr_t *ret)
+{
+	posix_spawnattr_t sa;
+
+	sa = calloc(1, sizeof(struct __posix_spawnattr));
+	if (sa == NULL)
+		return (errno);
+
+	/* Set defaults as specified by POSIX, cleared above */
+	*ret = sa;
+	return (0);
+}
+
+int
+posix_spawnattr_destroy(posix_spawnattr_t *sa)
+{
+	free(*sa);
+	return (0);
+}
+
+int
+posix_spawnattr_getflags(const posix_spawnattr_t *__restrict sa,
+    short *__restrict flags)
+{
+	*flags = (*sa)->sa_flags;
+	return (0);
+}
+
+int
+posix_spawnattr_getpgroup(const posix_spawnattr_t *__restrict sa,
+    pid_t *__restrict pgroup)
+{
+	*pgroup = (*sa)->sa_pgroup;
+	return (0);
+}
+
+int
+posix_spawnattr_getschedparam(const posix_spawnattr_t *__restrict sa,
+    struct sched_param *__restrict schedparam)
+{
+	*schedparam = (*sa)->sa_schedparam;
+	return (0);
+}
+
+int
+posix_spawnattr_getschedpolicy(const posix_spawnattr_t *__restrict sa,
+    int *__restrict schedpolicy)
+{
+	*schedpolicy = (*sa)->sa_schedpolicy;
+	return (0);
+}
+
+int
+posix_spawnattr_getsigdefault(const posix_spawnattr_t *__restrict sa,
+    sigset_t *__restrict sigdefault)
+{
+	*sigdefault = (*sa)->sa_sigdefault;
+	return (0);
+}
+
+int
+posix_spawnattr_getsigmask(const posix_spawnattr_t *__restrict sa,
+    sigset_t *__restrict sigmask)
+{
+	*sigmask = (*sa)->sa_sigmask;
+	return (0);
+}
+
+int
+posix_spawnattr_setflags(posix_spawnattr_t *sa, short flags)
+{
+	(*sa)->sa_flags = flags;
+	return (0);
+}
+
+int
+posix_spawnattr_setpgroup(posix_spawnattr_t *sa, pid_t pgroup)
+{
+	(*sa)->sa_pgroup = pgroup;
+	return (0);
+}
+
+int
+posix_spawnattr_setschedparam(posix_spawnattr_t *__restrict sa,
+    const struct sched_param *__restrict schedparam)
+{
+	(*sa)->sa_schedparam = *schedparam;
+	return (0);
+}
+
+int
+posix_spawnattr_setschedpolicy(posix_spawnattr_t *sa, int schedpolicy)
+{
+	(*sa)->sa_schedpolicy = schedpolicy;
+	return (0);
+}
+
+int
+posix_spawnattr_setsigdefault(posix_spawnattr_t *__restrict sa,
+    const sigset_t *__restrict sigdefault)
+{
+	(*sa)->sa_sigdefault = *sigdefault;
+	return (0);
+}
+
+int
+posix_spawnattr_setsigmask(posix_spawnattr_t *__restrict sa,
+    const sigset_t *__restrict sigmask)
+{
+	(*sa)->sa_sigmask = *sigmask;
+	return (0);
+}