initial implementation of posix_spawn

file actions are not yet implemented, but everything else should be
mostly complete and roughly correct.

include/spawn.h

+#ifndef _SPAWN_H
+#define _SPAWN_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define __NEED_mode_t
+#define __NEED_pid_t
+#define __NEED_sigset_t
+
+#include <bits/alltypes.h>
+
+struct sched_param;
+
+#define POSIX_SPAWN_RESETIDS 1
+#define POSIX_SPAWN_SETPGROUP 2
+#define POSIX_SPAWN_SETSIGDEF 4
+#define POSIX_SPAWN_SETSIGMASK 8
+#define POSIX_SPAWN_SETSCHEDPARAM 16
+#define POSIX_SPAWN_SETSCHEDULER 32
+
+typedef struct {
+	int __flags;
+	pid_t __pgrp;
+	sigset_t __def, __mask;
+	int __prio, __pol, __pad[16];
+} posix_spawnattr_t;
+
+typedef struct {
+	int __pad0[2];
+	void *__actions;
+	int __pad[16];
+} posix_spawn_file_actions_t;
+
+int posix_spawn(pid_t *, const char *, const posix_spawn_file_actions_t *,
+	const posix_spawnattr_t *, char **, char **);
+int posix_spawnp(pid_t *, const char *, const posix_spawn_file_actions_t *,
+	const posix_spawnattr_t *, char **, char **);
+
+int posix_spawnattr_init(posix_spawnattr_t *);
+int posix_spawnattr_destroy(posix_spawnattr_t *);
+
+int posix_spawnattr_setflags(posix_spawnattr_t *, short);
+int posix_spawnattr_getflags(const posix_spawnattr_t *, short *);
+
+int posix_spawnattr_setpgroup(posix_spawnattr_t *, pid_t);
+int posix_spawnattr_getpgroup(const posix_spawnattr_t *, pid_t *);
+
+int posix_spawnattr_setsigmask(posix_spawnattr_t *, const sigset_t *);
+int posix_spawnattr_getsigmask(const posix_spawnattr_t *, sigset_t *);
+
+int posix_spawnattr_setsigdefault(posix_spawnattr_t *, const sigset_t *);
+int posix_spawnattr_getsigdefault(const posix_spawnattr_t *, sigset_t *);
+
+int posix_spawn_file_actions_init(posix_spawn_file_actions_t *);
+int posix_spawn_file_actions_destroy(posix_spawn_file_actions_t *);
+
+int posix_spawn_file_actions_addopen(posix_spawn_file_actions_t *, int, const char *, int, mode_t);
+int posix_spawn_file_actions_addclose(posix_spawn_file_actions_t *, int);
+int posix_spawn_file_actions_adddup2(posix_spawn_file_actions_t *, int, int);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

src/process/posix_spawn.c

+#include <spawn.h>
+#include <unistd.h>
+#include <signal.h>
+#include <stdint.h>
+#include "syscall.h"
+
+extern char **environ;
+
+int __posix_spawnx(pid_t *res, const char *path,
+	int (*exec)(const char *, char *const *),
+	const posix_spawn_file_actions_t *fa,
+	const posix_spawnattr_t *attr, char **argv, char **envp)
+{
+	pid_t pid;
+	sigset_t oldmask;
+	int i;
+	posix_spawnattr_t dummy_attr = { 0 };
+
+	if (!attr) attr = &dummy_attr;
+
+	sigprocmask(SIG_BLOCK, (void *)(uint64_t []){-1}, &oldmask);
+	pid = __syscall(SYS_fork);
+
+	if (pid) {
+		sigprocmask(SIG_SETMASK, &oldmask, 0);
+		if (pid < 0) return -pid;
+		*res = pid;
+		return 0;
+	}
+
+	for (i=1; i<=64; i++) {
+		struct sigaction sa;
+		sigaction(i, 0, &sa);
+		if (sa.sa_handler!=SIG_IGN || sigismember(&attr->__def, i)) {
+			sa.sa_handler = SIG_DFL;
+			sigaction(i, &sa, 0);
+		}
+	}
+
+	if ((attr->__flags&POSIX_SPAWN_SETPGROUP) && setpgid(0, attr->__pgrp))
+		_exit(127);
+
+	/* Use syscalls directly because pthread state is not consistent
+	 * for making calls to the library wrappers... */
+	if ((attr->__flags&POSIX_SPAWN_RESETIDS) && (
+		__syscall(SYS_setgid, __syscall(SYS_getgid)) ||
+		__syscall(SYS_setuid, __syscall(SYS_getuid)) ))
+		_exit(127);
+
+	sigprocmask(SIG_SETMASK, (attr->__flags & POSIX_SPAWN_SETSIGMASK)
+		? &attr->__mask : &oldmask, 0);
+
+	if (envp) environ = envp;
+	exec(path, argv);
+	_exit(127);
+
+	return 0;
+}
+
+int posix_spawn(pid_t *res, const char *path,
+	const posix_spawn_file_actions_t *fa,
+	const posix_spawnattr_t *attr, char **argv, char **envp)
+{
+	return __posix_spawnx(res, path, execv, fa, attr, argv, envp);
+}

src/process/posix_spawn_file_actions_destroy.c

+#include <spawn.h>
+#include <stdlib.h>
+
+int posix_spawn_file_actions_destroy(posix_spawn_file_actions_t *fa)
+{
+	// FIXME
+	free(fa->__actions);
+	return 0;
+}

src/process/posix_spawn_file_actions_init.c

+#include <spawn.h>
+
+int posix_spawn_file_actions_init(posix_spawn_file_actions_t *fa)
+{
+	fa->__actions = 0;
+	return 0;
+}

src/process/posix_spawnattr_getflags.c

+#include <spawn.h>
+
+int posix_spawnattr_getflags(const posix_spawnattr_t *attr, short *flags)
+{
+	*flags = attr->__flags;
+	return 0;
+}

src/process/posix_spawnattr_getpgroup.c

+#include <spawn.h>
+
+int posix_spawnattr_getpgroup(const posix_spawnattr_t *attr, pid_t *pgrp)
+{
+	*pgrp = attr->__pgrp;
+	return 0;
+}

src/process/posix_spawnattr_getsigdefault.c

+#include <spawn.h>
+
+int posix_spawnattr_getsigdefault(const posix_spawnattr_t *attr, sigset_t *def)
+{
+	*def = attr->__def;
+	return 0;
+}

src/process/posix_spawnattr_getsigmask.c

+#include <spawn.h>
+
+int posix_spawnattr_getsigmask(const posix_spawnattr_t *attr, sigset_t *mask)
+{
+	*mask = attr->__mask;
+	return 0;
+}

src/process/posix_spawnattr_setflags.c

+#include <spawn.h>
+
+int posix_spawnattr_setflags(posix_spawnattr_t *attr, short flags)
+{
+	attr->__flags = flags;
+	return 0;
+}

src/process/posix_spawnattr_setpgroup.c

+#include <spawn.h>
+
+int posix_spawnattr_setpgroup(posix_spawnattr_t *attr, pid_t pgrp)
+{
+	attr->__pgrp = pgrp;
+	return 0;
+}

src/process/posix_spawnattr_setsigdefault.c

+#include <spawn.h>
+
+int posix_spawnattr_setsigdefault(posix_spawnattr_t *attr, const sigset_t *def)
+{
+	attr->__def = *def;
+	return 0;
+}

src/process/posix_spawnattr_setsigmask.c

+#include <spawn.h>
+
+int posix_spawnattr_setsigmask(posix_spawnattr_t *attr, const sigset_t *mask)
+{
+	attr->__mask = *mask;
+	return 0;
+}

src/process/posix_spawnp.c

+#include <spawn.h>
+#include <unistd.h>
+
+int __posix_spawnx(pid_t *, const char *,
+	int (*)(const char *, char *const *),
+	const posix_spawn_file_actions_t *,
+	const posix_spawnattr_t *, char **, char **);
+
+int posix_spawnp(pid_t *res, const char *file,
+	const posix_spawn_file_actions_t *fa,
+	const posix_spawnattr_t *attr, char **argv, char **envp)
+{
+	return __posix_spawnx(res, file, execvp, fa, attr, argv, envp);
+}