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/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include "uv.h"
#include "internal.h"
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <fcntl.h>
#include <poll.h>
#if defined(__APPLE__) && !TARGET_OS_IPHONE
# include <crt_externs.h>
# define environ (*_NSGetEnviron())
#else
extern char **environ;
#endif
#ifdef __linux__
# include <grp.h>
#endif
static void uv__chld(uv_signal_t* handle, int signum) {
uv_process_t* process;
uv_loop_t* loop;
int exit_status;
int term_signal;
int status;
pid_t pid;
QUEUE pending;
QUEUE* q;
QUEUE* h;
assert(signum == SIGCHLD);
QUEUE_INIT(&pending);
loop = handle->loop;
h = &loop->process_handles;
q = QUEUE_HEAD(h);
while (q != h) {
process = QUEUE_DATA(q, uv_process_t, queue);
q = QUEUE_NEXT(q);
do
pid = waitpid(process->pid, &status, WNOHANG);
while (pid == -1 && errno == EINTR);
if (pid == 0)
continue;
if (pid == -1) {
if (errno != ECHILD)
abort();
continue;
}
process->status = status;
QUEUE_REMOVE(&process->queue);
QUEUE_INSERT_TAIL(&pending, &process->queue);
}
h = &pending;
q = QUEUE_HEAD(h);
while (q != h) {
process = QUEUE_DATA(q, uv_process_t, queue);
q = QUEUE_NEXT(q);
QUEUE_REMOVE(&process->queue);
QUEUE_INIT(&process->queue);
uv__handle_stop(process);
if (process->exit_cb == NULL)
continue;
exit_status = 0;
if (WIFEXITED(process->status))
exit_status = WEXITSTATUS(process->status);
term_signal = 0;
if (WIFSIGNALED(process->status))
term_signal = WTERMSIG(process->status);
process->exit_cb(process, exit_status, term_signal);
}
assert(QUEUE_EMPTY(&pending));
}
int uv__make_socketpair(int fds[2], int flags) {
#if defined(__linux__)
static int no_cloexec;
if (no_cloexec)
goto skip;
if (socketpair(AF_UNIX, SOCK_STREAM | UV__SOCK_CLOEXEC | flags, 0, fds) == 0)
return 0;
/* Retry on EINVAL, it means SOCK_CLOEXEC is not supported.
* Anything else is a genuine error.
*/
if (errno != EINVAL)
return -errno;
no_cloexec = 1;
skip:
#endif
if (socketpair(AF_UNIX, SOCK_STREAM, 0, fds))
return -errno;
uv__cloexec(fds[0], 1);
uv__cloexec(fds[1], 1);
if (flags & UV__F_NONBLOCK) {
uv__nonblock(fds[0], 1);
uv__nonblock(fds[1], 1);
}
return 0;
}
int uv__make_pipe(int fds[2], int flags) {
#if defined(__linux__)
static int no_pipe2;
if (no_pipe2)
goto skip;
if (uv__pipe2(fds, flags | UV__O_CLOEXEC) == 0)
return 0;
if (errno != ENOSYS)
return -errno;
no_pipe2 = 1;
skip:
#endif
if (pipe(fds))
return -errno;
uv__cloexec(fds[0], 1);
uv__cloexec(fds[1], 1);
if (flags & UV__F_NONBLOCK) {
uv__nonblock(fds[0], 1);
uv__nonblock(fds[1], 1);
}
return 0;
}
/*
* Used for initializing stdio streams like options.stdin_stream. Returns
* zero on success. See also the cleanup section in uv_spawn().
*/
static int uv__process_init_stdio(uv_stdio_container_t* container, int fds[2]) {
int mask;
int fd;
mask = UV_IGNORE | UV_CREATE_PIPE | UV_INHERIT_FD | UV_INHERIT_STREAM;
switch (container->flags & mask) {
case UV_IGNORE:
return 0;
case UV_CREATE_PIPE:
assert(container->data.stream != NULL);
if (container->data.stream->type != UV_NAMED_PIPE)
return -EINVAL;
else
return uv__make_socketpair(fds, 0);
case UV_INHERIT_FD:
case UV_INHERIT_STREAM:
if (container->flags & UV_INHERIT_FD)
fd = container->data.fd;
else
fd = uv__stream_fd(container->data.stream);
if (fd == -1)
return -EINVAL;
fds[1] = fd;
return 0;
default:
assert(0 && "Unexpected flags");
return -EINVAL;
}
}
static int uv__process_open_stream(uv_stdio_container_t* container,
int pipefds[2],
int writable) {
int flags;
int err;
if (!(container->flags & UV_CREATE_PIPE) || pipefds[0] < 0)
return 0;
err = uv__close(pipefds[1]);
if (err != 0 && err != -EINPROGRESS)
abort();
pipefds[1] = -1;
uv__nonblock(pipefds[0], 1);
if (container->data.stream->type == UV_NAMED_PIPE &&
((uv_pipe_t*)container->data.stream)->ipc)
flags = UV_STREAM_READABLE | UV_STREAM_WRITABLE;
else if (writable)
flags = UV_STREAM_WRITABLE;
else
flags = UV_STREAM_READABLE;
return uv__stream_open(container->data.stream, pipefds[0], flags);
}
static void uv__process_close_stream(uv_stdio_container_t* container) {
if (!(container->flags & UV_CREATE_PIPE)) return;
uv__stream_close((uv_stream_t*)container->data.stream);
}
static void uv__write_int(int fd, int val) {
ssize_t n;
do
n = write(fd, &val, sizeof(val));
while (n == -1 && errno == EINTR);
if (n == -1 && errno == EPIPE)
return; /* parent process has quit */
assert(n == sizeof(val));
}
#if !(defined(__APPLE__) && (TARGET_OS_TV || TARGET_OS_WATCH))
/* execvp is marked __WATCHOS_PROHIBITED __TVOS_PROHIBITED, so must be
* avoided. Since this isn't called on those targets, the function
* doesn't even need to be defined for them.
*/
static void uv__process_child_init(const uv_process_options_t* options,
int stdio_count,
int (*pipes)[2],
int error_fd) {
int close_fd;
int use_fd;
int fd;
if (options->flags & UV_PROCESS_DETACHED)
setsid();
/* First duplicate low numbered fds, since it's not safe to duplicate them,
* they could get replaced. Example: swapping stdout and stderr; without
* this fd 2 (stderr) would be duplicated into fd 1, thus making both
* stdout and stderr go to the same fd, which was not the intention. */
for (fd = 0; fd < stdio_count; fd++) {
use_fd = pipes[fd][1];
if (use_fd < 0 || use_fd >= fd)
continue;
pipes[fd][1] = fcntl(use_fd, F_DUPFD, stdio_count);
if (pipes[fd][1] == -1) {
uv__write_int(error_fd, -errno);
_exit(127);
}
}
for (fd = 0; fd < stdio_count; fd++) {
close_fd = pipes[fd][0];
use_fd = pipes[fd][1];
if (use_fd < 0) {
if (fd >= 3)
continue;
else {
/* redirect stdin, stdout and stderr to /dev/null even if UV_IGNORE is
* set
*/
use_fd = open("/dev/null", fd == 0 ? O_RDONLY : O_RDWR);
close_fd = use_fd;
if (use_fd == -1) {
uv__write_int(error_fd, -errno);
_exit(127);
}
}
}
if (fd == use_fd)
uv__cloexec(use_fd, 0);
else
fd = dup2(use_fd, fd);
if (fd == -1) {
uv__write_int(error_fd, -errno);
_exit(127);
}
if (fd <= 2)
uv__nonblock(fd, 0);
if (close_fd >= stdio_count)
uv__close(close_fd);
}
for (fd = 0; fd < stdio_count; fd++) {
use_fd = pipes[fd][1];
if (use_fd >= stdio_count)
uv__close(use_fd);
}
if (options->cwd != NULL && chdir(options->cwd)) {
uv__write_int(error_fd, -errno);
_exit(127);
}
if (options->flags & (UV_PROCESS_SETUID | UV_PROCESS_SETGID)) {
/* When dropping privileges from root, the `setgroups` call will
* remove any extraneous groups. If we don't call this, then
* even though our uid has dropped, we may still have groups
* that enable us to do super-user things. This will fail if we
* aren't root, so don't bother checking the return value, this
* is just done as an optimistic privilege dropping function.
*/
SAVE_ERRNO(setgroups(0, NULL));
}
if ((options->flags & UV_PROCESS_SETGID) && setgid(options->gid)) {
uv__write_int(error_fd, -errno);
_exit(127);
}
if ((options->flags & UV_PROCESS_SETUID) && setuid(options->uid)) {
uv__write_int(error_fd, -errno);
_exit(127);
}
if (options->env != NULL) {
environ = options->env;
}
execvp(options->file, options->args);
uv__write_int(error_fd, -errno);
_exit(127);
}
#endif
int uv_spawn(uv_loop_t* loop,
uv_process_t* process,
const uv_process_options_t* options) {
#if defined(__APPLE__) && (TARGET_OS_TV || TARGET_OS_WATCH)
/* fork is marked __WATCHOS_PROHIBITED __TVOS_PROHIBITED. */
return -ENOSYS;
#else
int signal_pipe[2] = { -1, -1 };
int (*pipes)[2];
int stdio_count;
ssize_t r;
pid_t pid;
int err;
int exec_errorno;
int i;
int status;
assert(options->file != NULL);
assert(!(options->flags & ~(UV_PROCESS_DETACHED |
UV_PROCESS_SETGID |
UV_PROCESS_SETUID |
UV_PROCESS_WINDOWS_HIDE |
UV_PROCESS_WINDOWS_VERBATIM_ARGUMENTS)));
uv__handle_init(loop, (uv_handle_t*)process, UV_PROCESS);
QUEUE_INIT(&process->queue);
stdio_count = options->stdio_count;
if (stdio_count < 3)
stdio_count = 3;
err = -ENOMEM;
pipes = uv__malloc(stdio_count * sizeof(*pipes));
if (pipes == NULL)
goto error;
for (i = 0; i < stdio_count; i++) {
pipes[i][0] = -1;
pipes[i][1] = -1;
}
for (i = 0; i < options->stdio_count; i++) {
err = uv__process_init_stdio(options->stdio + i, pipes[i]);
if (err)
goto error;
}
/* This pipe is used by the parent to wait until
* the child has called `execve()`. We need this
* to avoid the following race condition:
*
* if ((pid = fork()) > 0) {
* kill(pid, SIGTERM);
* }
* else if (pid == 0) {
* execve("/bin/cat", argp, envp);
* }
*
* The parent sends a signal immediately after forking.
* Since the child may not have called `execve()` yet,
* there is no telling what process receives the signal,
* our fork or /bin/cat.
*
* To avoid ambiguity, we create a pipe with both ends
* marked close-on-exec. Then, after the call to `fork()`,
* the parent polls the read end until it EOFs or errors with EPIPE.
*/
err = uv__make_pipe(signal_pipe, 0);
if (err)
goto error;
uv_signal_start(&loop->child_watcher, uv__chld, SIGCHLD);
/* Acquire write lock to prevent opening new fds in worker threads */
uv_rwlock_wrlock(&loop->cloexec_lock);
pid = fork();
if (pid == -1) {
err = -errno;
uv_rwlock_wrunlock(&loop->cloexec_lock);
uv__close(signal_pipe[0]);
uv__close(signal_pipe[1]);
goto error;
}
if (pid == 0) {
uv__process_child_init(options, stdio_count, pipes, signal_pipe[1]);
abort();
}
/* Release lock in parent process */
uv_rwlock_wrunlock(&loop->cloexec_lock);
uv__close(signal_pipe[1]);
process->status = 0;
exec_errorno = 0;
do
r = read(signal_pipe[0], &exec_errorno, sizeof(exec_errorno));
while (r == -1 && errno == EINTR);
if (r == 0)
; /* okay, EOF */
else if (r == sizeof(exec_errorno)) {
do
err = waitpid(pid, &status, 0); /* okay, read errorno */
while (err == -1 && errno == EINTR);
assert(err == pid);
} else if (r == -1 && errno == EPIPE) {
do
err = waitpid(pid, &status, 0); /* okay, got EPIPE */
while (err == -1 && errno == EINTR);
assert(err == pid);
} else
abort();
uv__close(signal_pipe[0]);
for (i = 0; i < options->stdio_count; i++) {
err = uv__process_open_stream(options->stdio + i, pipes[i], i == 0);
if (err == 0)
continue;
while (i--)
uv__process_close_stream(options->stdio + i);
goto error;
}
/* Only activate this handle if exec() happened successfully */
if (exec_errorno == 0) {
QUEUE_INSERT_TAIL(&loop->process_handles, &process->queue);
uv__handle_start(process);
}
process->pid = pid;
process->exit_cb = options->exit_cb;
uv__free(pipes);
return exec_errorno;
error:
if (pipes != NULL) {
for (i = 0; i < stdio_count; i++) {
if (i < options->stdio_count)
if (options->stdio[i].flags & (UV_INHERIT_FD | UV_INHERIT_STREAM))
continue;
if (pipes[i][0] != -1)
close(pipes[i][0]);
if (pipes[i][1] != -1)
close(pipes[i][1]);
}
uv__free(pipes);
}
return err;
#endif
}
int uv_process_kill(uv_process_t* process, int signum) {
return uv_kill(process->pid, signum);
}
int uv_kill(int pid, int signum) {
if (kill(pid, signum))
return -errno;
else
return 0;
}
void uv__process_close(uv_process_t* handle) {
QUEUE_REMOVE(&handle->queue);
uv__handle_stop(handle);
if (QUEUE_EMPTY(&handle->loop->process_handles))
uv_signal_stop(&handle->loop->child_watcher);
}
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