| /* |
| * 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 <spawn.h> |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <signal.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <unistd.h> |
| |
| #include <android/fdsan.h> |
| |
| #include "private/ScopedSignalBlocker.h" |
| #include "private/SigSetConverter.h" |
| |
| 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 sigaction64 default_sa = { .sa_handler = SIG_DFL }; |
| for (int s = 1; s < _NSIG; ++s) { |
| bool reset = false; |
| if (use_sigdefault && sigismember64(&(*attr)->sigdefault.sigset64, s)) { |
| reset = true; |
| } else { |
| struct sigaction64 current; |
| if (sigaction64(s, nullptr, ¤t) == -1) _exit(127); |
| reset = (current.sa_handler != SIG_IGN && current.sa_handler != SIG_DFL); |
| } |
| if (reset && sigaction64(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 (sigprocmask64(SIG_SETMASK, &(*attr)->sigmask.sigset64, 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); |
| } |