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diff --git a/src/spawn.cc b/src/spawn.cc
new file mode 100644
index 0000000..1eed715
--- /dev/null
+++ b/src/spawn.cc
@@ -0,0 +1,381 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * 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 COPYRIGHT HOLDERS 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
+ * COPYRIGHT OWNER 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 <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <android/fdsan.h>
+
+#include "spawn.h"
+
+// Bionic "private/ScopedSignalBlocker.h" + one macro needed
+#define BIONIC_DISALLOW_COPY_AND_ASSIGN(TypeName) \
+ TypeName(const TypeName&) = delete; \
+ void operator=(const TypeName&) = delete
+
+class ScopedSignalBlocker {
+ public:
+ // Block all signals.
+ explicit ScopedSignalBlocker() {
+ sigset_t set;
+ sigfillset(&set);
+ sigprocmask(SIG_BLOCK, &set, &old_set_);
+ }
+
+ // Block just the specified signal.
+ explicit ScopedSignalBlocker(int signal) {
+ sigset_t set = {};
+ sigaddset(&set, signal);
+ sigprocmask(SIG_BLOCK, &set, &old_set_);
+ }
+
+ ~ScopedSignalBlocker() {
+ reset();
+ }
+
+ void reset() {
+ sigprocmask(SIG_SETMASK, &old_set_, nullptr);
+ }
+
+ sigset_t old_set_;
+
+ BIONIC_DISALLOW_COPY_AND_ASSIGN(ScopedSignalBlocker);
+};
+
+// Bionic "private/SigSetConverter.h"
+union SigSetConverter {
+ int bsd;
+ sigset_t sigset;
+ sigset64_t sigset64;
+};
+
+enum Action {
+ kOpen,
+ kClose,
+ kDup2
+};
+
+struct __posix_spawn_file_action {
+ __posix_spawn_file_action* next;
+
+ Action what;
+ int fd;
+ int new_fd;
+ char* path;
+ int flags;
+ mode_t mode;
+
+ void Do() {
+ if (what == kOpen) {
+ fd = open(path, flags, mode);
+ if (fd == -1) _exit(127);
+ // If it didn't land where we wanted it, move it.
+ if (fd != new_fd) {
+ if (dup2(fd, new_fd) == -1) _exit(127);
+ close(fd);
+ }
+ } else if (what == kClose) {
+ // Failure to close is ignored.
+ close(fd);
+ } else {
+ if (dup2(fd, new_fd) == -1) _exit(127);
+ }
+ }
+};
+
+struct __posix_spawn_file_actions {
+ __posix_spawn_file_action* head;
+ __posix_spawn_file_action* last;
+
+ void Do() {
+ for (__posix_spawn_file_action* action = head; action != nullptr; action = action->next) {
+ action->Do();
+ }
+ }
+};
+
+struct __posix_spawnattr {
+ short flags;
+ pid_t pgroup;
+ sched_param schedparam;
+ int schedpolicy;
+ SigSetConverter sigmask;
+ SigSetConverter sigdefault;
+};
+
+static void ApplyAttrs(short flags, const posix_spawnattr_t* attr) {
+ // POSIX: "If POSIX_SPAWN_SETSIGDEF is set ... signals in sigdefault ...
+ // shall be set to their default actions in the child process."
+ // POSIX: "Signals set to be caught by the calling process shall be
+ // set to the default action in the child process."
+ bool use_sigdefault = ((flags & POSIX_SPAWN_SETSIGDEF) != 0);
+ const struct sigaction default_sa = { .sa_handler = SIG_DFL };
+ for (int s = 1; s < _NSIG; ++s) {
+ bool reset = false;
+ if (use_sigdefault && sigismember(&(*attr)->sigdefault.sigset, s)) {
+ reset = true;
+ } else {
+ struct sigaction current;
+ if (sigaction(s, nullptr, &current) == -1) _exit(127);
+ reset = (current.sa_handler != SIG_IGN && current.sa_handler != SIG_DFL);
+ }
+ if (reset && sigaction(s, &default_sa, nullptr) == -1) _exit(127);
+ }
+
+ if ((flags & POSIX_SPAWN_SETPGROUP) != 0 && setpgid(0, (*attr)->pgroup) == -1) _exit(127);
+ if ((flags & POSIX_SPAWN_SETSID) != 0 && setsid() == -1) _exit(127);
+
+ // POSIX_SPAWN_SETSCHEDULER overrides POSIX_SPAWN_SETSCHEDPARAM, but it is not an error
+ // to set both.
+ if ((flags & POSIX_SPAWN_SETSCHEDULER) != 0) {
+ if (sched_setscheduler(0, (*attr)->schedpolicy, &(*attr)->schedparam) == -1) _exit(127);
+ } else if ((flags & POSIX_SPAWN_SETSCHEDPARAM) != 0) {
+ if (sched_setparam(0, &(*attr)->schedparam) == -1) _exit(127);
+ }
+
+ if ((flags & POSIX_SPAWN_RESETIDS) != 0) {
+ if (seteuid(getuid()) == -1 || setegid(getgid()) == -1) _exit(127);
+ }
+
+ if ((flags & POSIX_SPAWN_SETSIGMASK) != 0) {
+ if (sigprocmask(SIG_SETMASK, &(*attr)->sigmask.sigset, nullptr)) _exit(127);
+ }
+}
+
+static int posix_spawn(pid_t* pid_ptr,
+ const char* path,
+ const posix_spawn_file_actions_t* actions,
+ const posix_spawnattr_t* attr,
+ char* const argv[],
+ char* const env[],
+ int exec_fn(const char* path, char* const argv[], char* const env[])) {
+ // See http://man7.org/linux/man-pages/man3/posix_spawn.3.html
+ // and http://pubs.opengroup.org/onlinepubs/9699919799/functions/posix_spawn.html
+
+ ScopedSignalBlocker ssb;
+
+ short flags = attr ? (*attr)->flags : 0;
+ bool use_vfork = ((flags & POSIX_SPAWN_USEVFORK) != 0) || (actions == nullptr && flags == 0);
+
+ pid_t pid = use_vfork ? vfork() : fork();
+ if (pid == -1) return errno;
+
+ if (pid == 0) {
+ // Child.
+ ApplyAttrs(flags, attr);
+ if (actions) (*actions)->Do();
+ if ((flags & POSIX_SPAWN_SETSIGMASK) == 0) ssb.reset();
+ exec_fn(path, argv, env ? env : environ);
+ _exit(127);
+ }
+
+ // Parent.
+ if (pid_ptr) *pid_ptr = pid;
+ return 0;
+}
+
+int posix_spawn(pid_t* pid, const char* path, const posix_spawn_file_actions_t* actions,
+ const posix_spawnattr_t* attr, char* const argv[], char* const env[]) {
+ return posix_spawn(pid, path, actions, attr, argv, env, execve);
+}
+
+int posix_spawnp(pid_t* pid, const char* file, const posix_spawn_file_actions_t* actions,
+ const posix_spawnattr_t* attr, char* const argv[], char* const env[]) {
+ return posix_spawn(pid, file, actions, attr, argv, env, execvpe);
+}
+
+int posix_spawnattr_init(posix_spawnattr_t* attr) {
+ *attr = reinterpret_cast<__posix_spawnattr*>(calloc(1, sizeof(__posix_spawnattr)));
+ return (*attr == nullptr) ? errno : 0;
+}
+
+int posix_spawnattr_destroy(posix_spawnattr_t* attr) {
+ free(*attr);
+ *attr = nullptr;
+ return 0;
+}
+
+int posix_spawnattr_setflags(posix_spawnattr_t* attr, short flags) {
+ if ((flags & ~(POSIX_SPAWN_RESETIDS | POSIX_SPAWN_SETPGROUP | POSIX_SPAWN_SETSIGDEF |
+ POSIX_SPAWN_SETSIGMASK | POSIX_SPAWN_SETSCHEDPARAM | POSIX_SPAWN_SETSCHEDULER |
+ POSIX_SPAWN_USEVFORK | POSIX_SPAWN_SETSID)) != 0) {
+ return EINVAL;
+ }
+ (*attr)->flags = flags;
+ return 0;
+}
+
+int posix_spawnattr_getflags(const posix_spawnattr_t* attr, short* flags) {
+ *flags = (*attr)->flags;
+ return 0;
+}
+
+int posix_spawnattr_setpgroup(posix_spawnattr_t* attr, pid_t pgroup) {
+ (*attr)->pgroup = pgroup;
+ return 0;
+}
+
+int posix_spawnattr_getpgroup(const posix_spawnattr_t* attr, pid_t* pgroup) {
+ *pgroup = (*attr)->pgroup;
+ return 0;
+}
+
+int posix_spawnattr_setsigmask(posix_spawnattr_t* attr, const sigset_t* mask) {
+ (*attr)->sigmask.sigset = *mask;
+ return 0;
+}
+
+int posix_spawnattr_setsigmask64(posix_spawnattr_t* attr, const sigset64_t* mask) {
+ (*attr)->sigmask.sigset64 = *mask;
+ return 0;
+}
+
+int posix_spawnattr_getsigmask(const posix_spawnattr_t* attr, sigset_t* mask) {
+ *mask = (*attr)->sigmask.sigset;
+ return 0;
+}
+
+int posix_spawnattr_getsigmask64(const posix_spawnattr_t* attr, sigset64_t* mask) {
+ *mask = (*attr)->sigmask.sigset64;
+ return 0;
+}
+
+int posix_spawnattr_setsigdefault(posix_spawnattr_t* attr, const sigset_t* mask) {
+ (*attr)->sigdefault.sigset = *mask;
+ return 0;
+}
+
+int posix_spawnattr_setsigdefault64(posix_spawnattr_t* attr, const sigset64_t* mask) {
+ (*attr)->sigdefault.sigset64 = *mask;
+ return 0;
+}
+
+int posix_spawnattr_getsigdefault(const posix_spawnattr_t* attr, sigset_t* mask) {
+ *mask = (*attr)->sigdefault.sigset;
+ return 0;
+}
+
+int posix_spawnattr_getsigdefault64(const posix_spawnattr_t* attr, sigset64_t* mask) {
+ *mask = (*attr)->sigdefault.sigset64;
+ return 0;
+}
+
+int posix_spawnattr_setschedparam(posix_spawnattr_t* attr, const struct sched_param* param) {
+ (*attr)->schedparam = *param;
+ return 0;
+}
+
+int posix_spawnattr_getschedparam(const posix_spawnattr_t* attr, struct sched_param* param) {
+ *param = (*attr)->schedparam;
+ return 0;
+}
+
+int posix_spawnattr_setschedpolicy(posix_spawnattr_t* attr, int policy) {
+ (*attr)->schedpolicy = policy;
+ return 0;
+}
+
+int posix_spawnattr_getschedpolicy(const posix_spawnattr_t* attr, int* policy) {
+ *policy = (*attr)->schedpolicy;
+ return 0;
+}
+
+int posix_spawn_file_actions_init(posix_spawn_file_actions_t* actions) {
+ *actions = reinterpret_cast<__posix_spawn_file_actions*>(calloc(1, sizeof(**actions)));
+ return (*actions == nullptr) ? errno : 0;
+}
+
+int posix_spawn_file_actions_destroy(posix_spawn_file_actions_t* actions) {
+ __posix_spawn_file_action* a = (*actions)->head;
+ while (a) {
+ __posix_spawn_file_action* last = a;
+ a = a->next;
+ free(last->path);
+ free(last);
+ }
+ free(*actions);
+ *actions = nullptr;
+ return 0;
+}
+
+static int posix_spawn_add_file_action(posix_spawn_file_actions_t* actions,
+ Action what,
+ int fd,
+ int new_fd,
+ const char* path,
+ int flags,
+ mode_t mode) {
+ __posix_spawn_file_action* action =
+ reinterpret_cast<__posix_spawn_file_action*>(malloc(sizeof(*action)));
+ if (action == nullptr) return errno;
+
+ action->next = nullptr;
+ if (path != nullptr) {
+ action->path = strdup(path);
+ if (action->path == nullptr) {
+ free(action);
+ return errno;
+ }
+ } else {
+ action->path = nullptr;
+ }
+ action->what = what;
+ action->fd = fd;
+ action->new_fd = new_fd;
+ action->flags = flags;
+ action->mode = mode;
+
+ if ((*actions)->head == nullptr) {
+ (*actions)->head = (*actions)->last = action;
+ } else {
+ (*actions)->last->next = action;
+ (*actions)->last = action;
+ }
+
+ return 0;
+}
+
+int posix_spawn_file_actions_addopen(posix_spawn_file_actions_t* actions,
+ int fd, const char* path, int flags, mode_t mode) {
+ if (fd < 0) return EBADF;
+ return posix_spawn_add_file_action(actions, kOpen, -1, fd, path, flags, mode);
+}
+
+int posix_spawn_file_actions_addclose(posix_spawn_file_actions_t* actions, int fd) {
+ if (fd < 0) return EBADF;
+ return posix_spawn_add_file_action(actions, kClose, fd, -1, nullptr, 0, 0);
+}
+
+int posix_spawn_file_actions_adddup2(posix_spawn_file_actions_t* actions, int fd, int new_fd) {
+ if (fd < 0 || new_fd < 0) return EBADF;
+ return posix_spawn_add_file_action(actions, kDup2, fd, new_fd, nullptr, 0, 0);
+}