1#[cfg(target_os = "vxworks")]
2use libc::RTP_ID as pid_t;
3#[cfg(not(target_os = "vxworks"))]
4use libc::{c_int, pid_t};
5#[cfg(not(any(
6 target_os = "vxworks",
7 target_os = "l4re",
8 target_os = "tvos",
9 target_os = "watchos",
10)))]
11use libc::{gid_t, uid_t};
12
13use super::common::*;
14use crate::io::{self, Error, ErrorKind};
15use crate::num::NonZero;
16use crate::sys::cvt;
17#[cfg(target_os = "linux")]
18use crate::sys::pal::linux::pidfd::PidFd;
19use crate::{fmt, mem, sys};
20
21cfg_if::cfg_if! {
22 if #[cfg(target_os = "nto")] {
23 use crate::thread;
24 use libc::{c_char, posix_spawn_file_actions_t, posix_spawnattr_t};
25 use crate::time::Duration;
26 use crate::sync::LazyLock;
27 // Get smallest amount of time we can sleep.
28 // Return a common value if it cannot be determined.
29 fn get_clock_resolution() -> Duration {
30 static MIN_DELAY: LazyLock<Duration, fn() -> Duration> = LazyLock::new(|| {
31 let mut mindelay = libc::timespec { tv_sec: 0, tv_nsec: 0 };
32 if unsafe { libc::clock_getres(libc::CLOCK_MONOTONIC, &mut mindelay) } == 0
33 {
34 Duration::from_nanos(mindelay.tv_nsec as u64)
35 } else {
36 Duration::from_millis(1)
37 }
38 });
39 *MIN_DELAY
40 }
41 // Arbitrary minimum sleep duration for retrying fork/spawn
42 const MIN_FORKSPAWN_SLEEP: Duration = Duration::from_nanos(1);
43 // Maximum duration of sleeping before giving up and returning an error
44 const MAX_FORKSPAWN_SLEEP: Duration = Duration::from_millis(1000);
45 }
46}
47
48////////////////////////////////////////////////////////////////////////////////
49// Command
50////////////////////////////////////////////////////////////////////////////////
51
52impl Command {
53 pub fn spawn(
54 &mut self,
55 default: Stdio,
56 needs_stdin: bool,
57 ) -> io::Result<(Process, StdioPipes)> {
58 const CLOEXEC_MSG_FOOTER: [u8; 4] = *b"NOEX";
59
60 let envp = self.capture_env();
61
62 if self.saw_nul() {
63 return Err(io::const_error!(
64 ErrorKind::InvalidInput,
65 "nul byte found in provided data",
66 ));
67 }
68
69 let (ours, theirs) = self.setup_io(default, needs_stdin)?;
70
71 if let Some(ret) = self.posix_spawn(&theirs, envp.as_ref())? {
72 return Ok((ret, ours));
73 }
74
75 #[cfg(target_os = "linux")]
76 let (input, output) = sys::net::Socket::new_pair(libc::AF_UNIX, libc::SOCK_SEQPACKET)?;
77
78 #[cfg(not(target_os = "linux"))]
79 let (input, output) = sys::pipe::anon_pipe()?;
80
81 // Whatever happens after the fork is almost for sure going to touch or
82 // look at the environment in one way or another (PATH in `execvp` or
83 // accessing the `environ` pointer ourselves). Make sure no other thread
84 // is accessing the environment when we do the fork itself.
85 //
86 // Note that as soon as we're done with the fork there's no need to hold
87 // a lock any more because the parent won't do anything and the child is
88 // in its own process. Thus the parent drops the lock guard immediately.
89 // The child calls `mem::forget` to leak the lock, which is crucial because
90 // releasing a lock is not async-signal-safe.
91 let env_lock = sys::os::env_read_lock();
92 let pid = unsafe { self.do_fork()? };
93
94 if pid == 0 {
95 crate::panic::always_abort();
96 mem::forget(env_lock); // avoid non-async-signal-safe unlocking
97 drop(input);
98 #[cfg(target_os = "linux")]
99 if self.get_create_pidfd() {
100 self.send_pidfd(&output);
101 }
102 let Err(err) = unsafe { self.do_exec(theirs, envp.as_ref()) };
103 let errno = err.raw_os_error().unwrap_or(libc::EINVAL) as u32;
104 let errno = errno.to_be_bytes();
105 let bytes = [
106 errno[0],
107 errno[1],
108 errno[2],
109 errno[3],
110 CLOEXEC_MSG_FOOTER[0],
111 CLOEXEC_MSG_FOOTER[1],
112 CLOEXEC_MSG_FOOTER[2],
113 CLOEXEC_MSG_FOOTER[3],
114 ];
115 // pipe I/O up to PIPE_BUF bytes should be atomic, and then
116 // we want to be sure we *don't* run at_exit destructors as
117 // we're being torn down regardless
118 rtassert!(output.write(&bytes).is_ok());
119 unsafe { libc::_exit(1) }
120 }
121
122 drop(env_lock);
123 drop(output);
124
125 #[cfg(target_os = "linux")]
126 let pidfd = if self.get_create_pidfd() { self.recv_pidfd(&input) } else { -1 };
127
128 #[cfg(not(target_os = "linux"))]
129 let pidfd = -1;
130
131 // Safety: We obtained the pidfd (on Linux) using SOCK_SEQPACKET, so it's valid.
132 let mut p = unsafe { Process::new(pid, pidfd) };
133 let mut bytes = [0; 8];
134
135 // loop to handle EINTR
136 loop {
137 match input.read(&mut bytes) {
138 Ok(0) => return Ok((p, ours)),
139 Ok(8) => {
140 let (errno, footer) = bytes.split_at(4);
141 assert_eq!(
142 CLOEXEC_MSG_FOOTER, footer,
143 "Validation on the CLOEXEC pipe failed: {:?}",
144 bytes
145 );
146 let errno = i32::from_be_bytes(errno.try_into().unwrap());
147 assert!(p.wait().is_ok(), "wait() should either return Ok or panic");
148 return Err(Error::from_raw_os_error(errno));
149 }
150 Err(ref e) if e.is_interrupted() => {}
151 Err(e) => {
152 assert!(p.wait().is_ok(), "wait() should either return Ok or panic");
153 panic!("the CLOEXEC pipe failed: {e:?}")
154 }
155 Ok(..) => {
156 // pipe I/O up to PIPE_BUF bytes should be atomic
157 // similarly SOCK_SEQPACKET messages should arrive whole
158 assert!(p.wait().is_ok(), "wait() should either return Ok or panic");
159 panic!("short read on the CLOEXEC pipe")
160 }
161 }
162 }
163 }
164
165 pub fn output(&mut self) -> io::Result<(ExitStatus, Vec<u8>, Vec<u8>)> {
166 let (proc, pipes) = self.spawn(Stdio::MakePipe, false)?;
167 crate::sys_common::process::wait_with_output(proc, pipes)
168 }
169
170 // WatchOS and TVOS headers mark the `fork`/`exec*` functions with
171 // `__WATCHOS_PROHIBITED __TVOS_PROHIBITED`, and indicate that the
172 // `posix_spawn*` functions should be used instead. It isn't entirely clear
173 // what `PROHIBITED` means here (e.g. if calls to these functions are
174 // allowed to exist in dead code), but it sounds bad, so we go out of our
175 // way to avoid that all-together.
176 #[cfg(any(target_os = "tvos", target_os = "watchos"))]
177 const ERR_APPLE_TV_WATCH_NO_FORK_EXEC: Error = io::const_error!(
178 ErrorKind::Unsupported,
179 "`fork`+`exec`-based process spawning is not supported on this target",
180 );
181
182 #[cfg(any(target_os = "tvos", target_os = "watchos"))]
183 unsafe fn do_fork(&mut self) -> Result<pid_t, io::Error> {
184 return Err(Self::ERR_APPLE_TV_WATCH_NO_FORK_EXEC);
185 }
186
187 // Attempts to fork the process. If successful, returns Ok((0, -1))
188 // in the child, and Ok((child_pid, -1)) in the parent.
189 #[cfg(not(any(target_os = "watchos", target_os = "tvos", target_os = "nto")))]
190 unsafe fn do_fork(&mut self) -> Result<pid_t, io::Error> {
191 cvt(libc::fork())
192 }
193
194 // On QNX Neutrino, fork can fail with EBADF in case "another thread might have opened
195 // or closed a file descriptor while the fork() was occurring".
196 // Documentation says "... or try calling fork() again". This is what we do here.
197 // See also https://www.qnx.com/developers/docs/7.1/#com.qnx.doc.neutrino.lib_ref/topic/f/fork.html
198 #[cfg(target_os = "nto")]
199 unsafe fn do_fork(&mut self) -> Result<pid_t, io::Error> {
200 use crate::sys::os::errno;
201
202 let mut delay = MIN_FORKSPAWN_SLEEP;
203
204 loop {
205 let r = libc::fork();
206 if r == -1 as libc::pid_t && errno() as libc::c_int == libc::EBADF {
207 if delay < get_clock_resolution() {
208 // We cannot sleep this short (it would be longer).
209 // Yield instead.
210 thread::yield_now();
211 } else if delay < MAX_FORKSPAWN_SLEEP {
212 thread::sleep(delay);
213 } else {
214 return Err(io::const_error!(
215 ErrorKind::WouldBlock,
216 "forking returned EBADF too often",
217 ));
218 }
219 delay *= 2;
220 continue;
221 } else {
222 return cvt(r);
223 }
224 }
225 }
226
227 pub fn exec(&mut self, default: Stdio) -> io::Error {
228 let envp = self.capture_env();
229
230 if self.saw_nul() {
231 return io::const_error!(ErrorKind::InvalidInput, "nul byte found in provided data");
232 }
233
234 match self.setup_io(default, true) {
235 Ok((_, theirs)) => {
236 unsafe {
237 // Similar to when forking, we want to ensure that access to
238 // the environment is synchronized, so make sure to grab the
239 // environment lock before we try to exec.
240 let _lock = sys::os::env_read_lock();
241
242 let Err(e) = self.do_exec(theirs, envp.as_ref());
243 e
244 }
245 }
246 Err(e) => e,
247 }
248 }
249
250 // And at this point we've reached a special time in the life of the
251 // child. The child must now be considered hamstrung and unable to
252 // do anything other than syscalls really. Consider the following
253 // scenario:
254 //
255 // 1. Thread A of process 1 grabs the malloc() mutex
256 // 2. Thread B of process 1 forks(), creating thread C
257 // 3. Thread C of process 2 then attempts to malloc()
258 // 4. The memory of process 2 is the same as the memory of
259 // process 1, so the mutex is locked.
260 //
261 // This situation looks a lot like deadlock, right? It turns out
262 // that this is what pthread_atfork() takes care of, which is
263 // presumably implemented across platforms. The first thing that
264 // threads to *before* forking is to do things like grab the malloc
265 // mutex, and then after the fork they unlock it.
266 //
267 // Despite this information, libnative's spawn has been witnessed to
268 // deadlock on both macOS and FreeBSD. I'm not entirely sure why, but
269 // all collected backtraces point at malloc/free traffic in the
270 // child spawned process.
271 //
272 // For this reason, the block of code below should contain 0
273 // invocations of either malloc of free (or their related friends).
274 //
275 // As an example of not having malloc/free traffic, we don't close
276 // this file descriptor by dropping the FileDesc (which contains an
277 // allocation). Instead we just close it manually. This will never
278 // have the drop glue anyway because this code never returns (the
279 // child will either exec() or invoke libc::exit)
280 #[cfg(not(any(target_os = "tvos", target_os = "watchos")))]
281 unsafe fn do_exec(
282 &mut self,
283 stdio: ChildPipes,
284 maybe_envp: Option<&CStringArray>,
285 ) -> Result<!, io::Error> {
286 use crate::sys::{self, cvt_r};
287
288 if let Some(fd) = stdio.stdin.fd() {
289 cvt_r(|| libc::dup2(fd, libc::STDIN_FILENO))?;
290 }
291 if let Some(fd) = stdio.stdout.fd() {
292 cvt_r(|| libc::dup2(fd, libc::STDOUT_FILENO))?;
293 }
294 if let Some(fd) = stdio.stderr.fd() {
295 cvt_r(|| libc::dup2(fd, libc::STDERR_FILENO))?;
296 }
297
298 #[cfg(not(target_os = "l4re"))]
299 {
300 if let Some(_g) = self.get_groups() {
301 //FIXME: Redox kernel does not support setgroups yet
302 #[cfg(not(target_os = "redox"))]
303 cvt(libc::setgroups(_g.len().try_into().unwrap(), _g.as_ptr()))?;
304 }
305 if let Some(u) = self.get_gid() {
306 cvt(libc::setgid(u as gid_t))?;
307 }
308 if let Some(u) = self.get_uid() {
309 // When dropping privileges from root, the `setgroups` call
310 // will remove any extraneous groups. We only drop groups
311 // if we have CAP_SETGID and we weren't given an explicit
312 // set of groups. If we don't call this, then even though our
313 // uid has dropped, we may still have groups that enable us to
314 // do super-user things.
315 //FIXME: Redox kernel does not support setgroups yet
316 #[cfg(not(target_os = "redox"))]
317 if self.get_groups().is_none() {
318 let res = cvt(libc::setgroups(0, crate::ptr::null()));
319 if let Err(e) = res {
320 // Here we ignore the case of not having CAP_SETGID.
321 // An alternative would be to require CAP_SETGID (in
322 // addition to CAP_SETUID) for setting the UID.
323 if e.raw_os_error() != Some(libc::EPERM) {
324 return Err(e.into());
325 }
326 }
327 }
328 cvt(libc::setuid(u as uid_t))?;
329 }
330 }
331 if let Some(cwd) = self.get_cwd() {
332 cvt(libc::chdir(cwd.as_ptr()))?;
333 }
334
335 if let Some(pgroup) = self.get_pgroup() {
336 cvt(libc::setpgid(0, pgroup))?;
337 }
338
339 // emscripten has no signal support.
340 #[cfg(not(target_os = "emscripten"))]
341 {
342 // Inherit the signal mask from the parent rather than resetting it (i.e. do not call
343 // pthread_sigmask).
344
345 // If -Zon-broken-pipe is used, don't reset SIGPIPE to SIG_DFL.
346 // If -Zon-broken-pipe is not used, reset SIGPIPE to SIG_DFL for backward compatibility.
347 //
348 // -Zon-broken-pipe is an opportunity to change the default here.
349 if !crate::sys::pal::on_broken_pipe_flag_used() {
350 #[cfg(target_os = "android")] // see issue #88585
351 {
352 let mut action: libc::sigaction = mem::zeroed();
353 action.sa_sigaction = libc::SIG_DFL;
354 cvt(libc::sigaction(libc::SIGPIPE, &action, crate::ptr::null_mut()))?;
355 }
356 #[cfg(not(target_os = "android"))]
357 {
358 let ret = sys::signal(libc::SIGPIPE, libc::SIG_DFL);
359 if ret == libc::SIG_ERR {
360 return Err(io::Error::last_os_error());
361 }
362 }
363 #[cfg(target_os = "hurd")]
364 {
365 let ret = sys::signal(libc::SIGLOST, libc::SIG_DFL);
366 if ret == libc::SIG_ERR {
367 return Err(io::Error::last_os_error());
368 }
369 }
370 }
371 }
372
373 for callback in self.get_closures().iter_mut() {
374 callback()?;
375 }
376
377 // Although we're performing an exec here we may also return with an
378 // error from this function (without actually exec'ing) in which case we
379 // want to be sure to restore the global environment back to what it
380 // once was, ensuring that our temporary override, when free'd, doesn't
381 // corrupt our process's environment.
382 let mut _reset = None;
383 if let Some(envp) = maybe_envp {
384 struct Reset(*const *const libc::c_char);
385
386 impl Drop for Reset {
387 fn drop(&mut self) {
388 unsafe {
389 *sys::os::environ() = self.0;
390 }
391 }
392 }
393
394 _reset = Some(Reset(*sys::os::environ()));
395 *sys::os::environ() = envp.as_ptr();
396 }
397
398 libc::execvp(self.get_program_cstr().as_ptr(), self.get_argv().as_ptr());
399 Err(io::Error::last_os_error())
400 }
401
402 #[cfg(any(target_os = "tvos", target_os = "watchos"))]
403 unsafe fn do_exec(
404 &mut self,
405 _stdio: ChildPipes,
406 _maybe_envp: Option<&CStringArray>,
407 ) -> Result<!, io::Error> {
408 return Err(Self::ERR_APPLE_TV_WATCH_NO_FORK_EXEC);
409 }
410
411 #[cfg(not(any(
412 target_os = "freebsd",
413 target_os = "illumos",
414 all(target_os = "linux", target_env = "gnu"),
415 all(target_os = "linux", target_env = "musl"),
416 target_os = "nto",
417 target_vendor = "apple",
418 )))]
419 fn posix_spawn(
420 &mut self,
421 _: &ChildPipes,
422 _: Option<&CStringArray>,
423 ) -> io::Result<Option<Process>> {
424 Ok(None)
425 }
426
427 // Only support platforms for which posix_spawn() can return ENOENT
428 // directly.
429 #[cfg(any(
430 target_os = "freebsd",
431 target_os = "illumos",
432 all(target_os = "linux", target_env = "gnu"),
433 all(target_os = "linux", target_env = "musl"),
434 target_os = "nto",
435 target_vendor = "apple",
436 ))]
437 // FIXME(#115199): Rust currently omits weak function definitions
438 // and its metadata from LLVM IR.
439 #[cfg_attr(target_os = "linux", no_sanitize(cfi))]
440 fn posix_spawn(
441 &mut self,
442 stdio: &ChildPipes,
443 envp: Option<&CStringArray>,
444 ) -> io::Result<Option<Process>> {
445 #[cfg(target_os = "linux")]
446 use core::sync::atomic::{AtomicU8, Ordering};
447
448 use crate::mem::MaybeUninit;
449 use crate::sys::{self, cvt_nz, on_broken_pipe_flag_used};
450
451 if self.get_gid().is_some()
452 || self.get_uid().is_some()
453 || (self.env_saw_path() && !self.program_is_path())
454 || !self.get_closures().is_empty()
455 || self.get_groups().is_some()
456 {
457 return Ok(None);
458 }
459
460 cfg_if::cfg_if! {
461 if #[cfg(target_os = "linux")] {
462 use crate::sys::weak::weak;
463
464 weak! {
465 fn pidfd_spawnp(
466 *mut libc::c_int,
467 *const libc::c_char,
468 *const libc::posix_spawn_file_actions_t,
469 *const libc::posix_spawnattr_t,
470 *const *mut libc::c_char,
471 *const *mut libc::c_char
472 ) -> libc::c_int
473 }
474
475 weak! { fn pidfd_getpid(libc::c_int) -> libc::c_int }
476
477 static PIDFD_SUPPORTED: AtomicU8 = AtomicU8::new(0);
478 const UNKNOWN: u8 = 0;
479 const SPAWN: u8 = 1;
480 // Obtaining a pidfd via the fork+exec path might work
481 const FORK_EXEC: u8 = 2;
482 // Neither pidfd_spawn nor fork/exec will get us a pidfd.
483 // Instead we'll just posix_spawn if the other preconditions are met.
484 const NO: u8 = 3;
485
486 if self.get_create_pidfd() {
487 let mut support = PIDFD_SUPPORTED.load(Ordering::Relaxed);
488 if support == FORK_EXEC {
489 return Ok(None);
490 }
491 if support == UNKNOWN {
492 support = NO;
493 let our_pid = crate::process::id();
494 let pidfd = cvt(unsafe { libc::syscall(libc::SYS_pidfd_open, our_pid, 0) } as c_int);
495 match pidfd {
496 Ok(pidfd) => {
497 support = FORK_EXEC;
498 if let Some(Ok(pid)) = pidfd_getpid.get().map(|f| cvt(unsafe { f(pidfd) } as i32)) {
499 if pidfd_spawnp.get().is_some() && pid as u32 == our_pid {
500 support = SPAWN
501 }
502 }
503 unsafe { libc::close(pidfd) };
504 }
505 Err(e) if e.raw_os_error() == Some(libc::EMFILE) => {
506 // We're temporarily(?) out of file descriptors. In this case obtaining a pidfd would also fail
507 // Don't update the support flag so we can probe again later.
508 return Err(e)
509 }
510 _ => {}
511 }
512 PIDFD_SUPPORTED.store(support, Ordering::Relaxed);
513 if support == FORK_EXEC {
514 return Ok(None);
515 }
516 }
517 core::assert_matches::debug_assert_matches!(support, SPAWN | NO);
518 }
519 } else {
520 if self.get_create_pidfd() {
521 unreachable!("only implemented on linux")
522 }
523 }
524 }
525
526 // Only glibc 2.24+ posix_spawn() supports returning ENOENT directly.
527 #[cfg(all(target_os = "linux", target_env = "gnu"))]
528 {
529 if let Some(version) = sys::os::glibc_version() {
530 if version < (2, 24) {
531 return Ok(None);
532 }
533 } else {
534 return Ok(None);
535 }
536 }
537
538 // On QNX Neutrino, posix_spawnp can fail with EBADF in case "another thread might have opened
539 // or closed a file descriptor while the posix_spawn() was occurring".
540 // Documentation says "... or try calling posix_spawn() again". This is what we do here.
541 // See also http://www.qnx.com/developers/docs/7.1/#com.qnx.doc.neutrino.lib_ref/topic/p/posix_spawn.html
542 #[cfg(target_os = "nto")]
543 unsafe fn retrying_libc_posix_spawnp(
544 pid: *mut pid_t,
545 file: *const c_char,
546 file_actions: *const posix_spawn_file_actions_t,
547 attrp: *const posix_spawnattr_t,
548 argv: *const *mut c_char,
549 envp: *const *mut c_char,
550 ) -> io::Result<i32> {
551 let mut delay = MIN_FORKSPAWN_SLEEP;
552 loop {
553 match libc::posix_spawnp(pid, file, file_actions, attrp, argv, envp) {
554 libc::EBADF => {
555 if delay < get_clock_resolution() {
556 // We cannot sleep this short (it would be longer).
557 // Yield instead.
558 thread::yield_now();
559 } else if delay < MAX_FORKSPAWN_SLEEP {
560 thread::sleep(delay);
561 } else {
562 return Err(io::const_error!(
563 ErrorKind::WouldBlock,
564 "posix_spawnp returned EBADF too often",
565 ));
566 }
567 delay *= 2;
568 continue;
569 }
570 r => {
571 return Ok(r);
572 }
573 }
574 }
575 }
576
577 type PosixSpawnAddChdirFn = unsafe extern "C" fn(
578 *mut libc::posix_spawn_file_actions_t,
579 *const libc::c_char,
580 ) -> libc::c_int;
581
582 /// Get the function pointer for adding a chdir action to a
583 /// `posix_spawn_file_actions_t`, if available, assuming a dynamic libc.
584 ///
585 /// Some platforms can set a new working directory for a spawned process in the
586 /// `posix_spawn` path. This function looks up the function pointer for adding
587 /// such an action to a `posix_spawn_file_actions_t` struct.
588 #[cfg(not(all(target_os = "linux", target_env = "musl")))]
589 fn get_posix_spawn_addchdir() -> Option<PosixSpawnAddChdirFn> {
590 use crate::sys::weak::weak;
591
592 // POSIX.1-2024 standardizes this function:
593 // https://pubs.opengroup.org/onlinepubs/9799919799/functions/posix_spawn_file_actions_addchdir.html.
594 // The _np version is more widely available, though, so try that first.
595
596 weak! {
597 fn posix_spawn_file_actions_addchdir_np(
598 *mut libc::posix_spawn_file_actions_t,
599 *const libc::c_char
600 ) -> libc::c_int
601 }
602
603 weak! {
604 fn posix_spawn_file_actions_addchdir(
605 *mut libc::posix_spawn_file_actions_t,
606 *const libc::c_char
607 ) -> libc::c_int
608 }
609
610 posix_spawn_file_actions_addchdir_np
611 .get()
612 .or_else(|| posix_spawn_file_actions_addchdir.get())
613 }
614
615 /// Get the function pointer for adding a chdir action to a
616 /// `posix_spawn_file_actions_t`, if available, on platforms where the function
617 /// is known to exist.
618 ///
619 /// Weak symbol lookup doesn't work with statically linked libcs, so in cases
620 /// where static linking is possible we need to either check for the presence
621 /// of the symbol at compile time or know about it upfront.
622 #[cfg(all(target_os = "linux", target_env = "musl"))]
623 fn get_posix_spawn_addchdir() -> Option<PosixSpawnAddChdirFn> {
624 // Our minimum required musl supports this function, so we can just use it.
625 Some(libc::posix_spawn_file_actions_addchdir_np)
626 }
627
628 let addchdir = match self.get_cwd() {
629 Some(cwd) => {
630 if cfg!(target_vendor = "apple") {
631 // There is a bug in macOS where a relative executable
632 // path like "../myprogram" will cause `posix_spawn` to
633 // successfully launch the program, but erroneously return
634 // ENOENT when used with posix_spawn_file_actions_addchdir_np
635 // which was introduced in macOS 10.15.
636 if self.get_program_kind() == ProgramKind::Relative {
637 return Ok(None);
638 }
639 }
640 // Check for the availability of the posix_spawn addchdir
641 // function now. If it isn't available, bail and use the
642 // fork/exec path.
643 match get_posix_spawn_addchdir() {
644 Some(f) => Some((f, cwd)),
645 None => return Ok(None),
646 }
647 }
648 None => None,
649 };
650
651 let pgroup = self.get_pgroup();
652
653 struct PosixSpawnFileActions<'a>(&'a mut MaybeUninit<libc::posix_spawn_file_actions_t>);
654
655 impl Drop for PosixSpawnFileActions<'_> {
656 fn drop(&mut self) {
657 unsafe {
658 libc::posix_spawn_file_actions_destroy(self.0.as_mut_ptr());
659 }
660 }
661 }
662
663 struct PosixSpawnattr<'a>(&'a mut MaybeUninit<libc::posix_spawnattr_t>);
664
665 impl Drop for PosixSpawnattr<'_> {
666 fn drop(&mut self) {
667 unsafe {
668 libc::posix_spawnattr_destroy(self.0.as_mut_ptr());
669 }
670 }
671 }
672
673 unsafe {
674 let mut attrs = MaybeUninit::uninit();
675 cvt_nz(libc::posix_spawnattr_init(attrs.as_mut_ptr()))?;
676 let attrs = PosixSpawnattr(&mut attrs);
677
678 let mut flags = 0;
679
680 let mut file_actions = MaybeUninit::uninit();
681 cvt_nz(libc::posix_spawn_file_actions_init(file_actions.as_mut_ptr()))?;
682 let file_actions = PosixSpawnFileActions(&mut file_actions);
683
684 if let Some(fd) = stdio.stdin.fd() {
685 cvt_nz(libc::posix_spawn_file_actions_adddup2(
686 file_actions.0.as_mut_ptr(),
687 fd,
688 libc::STDIN_FILENO,
689 ))?;
690 }
691 if let Some(fd) = stdio.stdout.fd() {
692 cvt_nz(libc::posix_spawn_file_actions_adddup2(
693 file_actions.0.as_mut_ptr(),
694 fd,
695 libc::STDOUT_FILENO,
696 ))?;
697 }
698 if let Some(fd) = stdio.stderr.fd() {
699 cvt_nz(libc::posix_spawn_file_actions_adddup2(
700 file_actions.0.as_mut_ptr(),
701 fd,
702 libc::STDERR_FILENO,
703 ))?;
704 }
705 if let Some((f, cwd)) = addchdir {
706 cvt_nz(f(file_actions.0.as_mut_ptr(), cwd.as_ptr()))?;
707 }
708
709 if let Some(pgroup) = pgroup {
710 flags |= libc::POSIX_SPAWN_SETPGROUP;
711 cvt_nz(libc::posix_spawnattr_setpgroup(attrs.0.as_mut_ptr(), pgroup))?;
712 }
713
714 // Inherit the signal mask from this process rather than resetting it (i.e. do not call
715 // posix_spawnattr_setsigmask).
716
717 // If -Zon-broken-pipe is used, don't reset SIGPIPE to SIG_DFL.
718 // If -Zon-broken-pipe is not used, reset SIGPIPE to SIG_DFL for backward compatibility.
719 //
720 // -Zon-broken-pipe is an opportunity to change the default here.
721 if !on_broken_pipe_flag_used() {
722 let mut default_set = MaybeUninit::<libc::sigset_t>::uninit();
723 cvt(sigemptyset(default_set.as_mut_ptr()))?;
724 cvt(sigaddset(default_set.as_mut_ptr(), libc::SIGPIPE))?;
725 #[cfg(target_os = "hurd")]
726 {
727 cvt(sigaddset(default_set.as_mut_ptr(), libc::SIGLOST))?;
728 }
729 cvt_nz(libc::posix_spawnattr_setsigdefault(
730 attrs.0.as_mut_ptr(),
731 default_set.as_ptr(),
732 ))?;
733 flags |= libc::POSIX_SPAWN_SETSIGDEF;
734 }
735
736 cvt_nz(libc::posix_spawnattr_setflags(attrs.0.as_mut_ptr(), flags as _))?;
737
738 // Make sure we synchronize access to the global `environ` resource
739 let _env_lock = sys::os::env_read_lock();
740 let envp = envp.map(|c| c.as_ptr()).unwrap_or_else(|| *sys::os::environ() as *const _);
741
742 #[cfg(not(target_os = "nto"))]
743 let spawn_fn = libc::posix_spawnp;
744 #[cfg(target_os = "nto")]
745 let spawn_fn = retrying_libc_posix_spawnp;
746
747 #[cfg(target_os = "linux")]
748 if self.get_create_pidfd() && PIDFD_SUPPORTED.load(Ordering::Relaxed) == SPAWN {
749 let mut pidfd: libc::c_int = -1;
750 let spawn_res = pidfd_spawnp.get().unwrap()(
751 &mut pidfd,
752 self.get_program_cstr().as_ptr(),
753 file_actions.0.as_ptr(),
754 attrs.0.as_ptr(),
755 self.get_argv().as_ptr() as *const _,
756 envp as *const _,
757 );
758
759 let spawn_res = cvt_nz(spawn_res);
760 if let Err(ref e) = spawn_res
761 && e.raw_os_error() == Some(libc::ENOSYS)
762 {
763 PIDFD_SUPPORTED.store(FORK_EXEC, Ordering::Relaxed);
764 return Ok(None);
765 }
766 spawn_res?;
767
768 let pid = match cvt(pidfd_getpid.get().unwrap()(pidfd)) {
769 Ok(pid) => pid,
770 Err(e) => {
771 // The child has been spawned and we are holding its pidfd.
772 // But we cannot obtain its pid even though pidfd_getpid support was verified earlier.
773 // This might happen if libc can't open procfs because the file descriptor limit has been reached.
774 libc::close(pidfd);
775 return Err(Error::new(
776 e.kind(),
777 "pidfd_spawnp succeeded but the child's PID could not be obtained",
778 ));
779 }
780 };
781
782 return Ok(Some(Process::new(pid, pidfd)));
783 }
784
785 // Safety: -1 indicates we don't have a pidfd.
786 let mut p = Process::new(0, -1);
787
788 let spawn_res = spawn_fn(
789 &mut p.pid,
790 self.get_program_cstr().as_ptr(),
791 file_actions.0.as_ptr(),
792 attrs.0.as_ptr(),
793 self.get_argv().as_ptr() as *const _,
794 envp as *const _,
795 );
796
797 #[cfg(target_os = "nto")]
798 let spawn_res = spawn_res?;
799
800 cvt_nz(spawn_res)?;
801 Ok(Some(p))
802 }
803 }
804
805 #[cfg(target_os = "linux")]
806 fn send_pidfd(&self, sock: &crate::sys::net::Socket) {
807 use libc::{CMSG_DATA, CMSG_FIRSTHDR, CMSG_LEN, CMSG_SPACE, SCM_RIGHTS, SOL_SOCKET};
808
809 use crate::io::IoSlice;
810 use crate::os::fd::RawFd;
811 use crate::sys::cvt_r;
812
813 unsafe {
814 let child_pid = libc::getpid();
815 // pidfd_open sets CLOEXEC by default
816 let pidfd = libc::syscall(libc::SYS_pidfd_open, child_pid, 0);
817
818 let fds: [c_int; 1] = [pidfd as RawFd];
819
820 const SCM_MSG_LEN: usize = size_of::<[c_int; 1]>();
821
822 #[repr(C)]
823 union Cmsg {
824 buf: [u8; unsafe { CMSG_SPACE(SCM_MSG_LEN as u32) as usize }],
825 _align: libc::cmsghdr,
826 }
827
828 let mut cmsg: Cmsg = mem::zeroed();
829
830 // 0-length message to send through the socket so we can pass along the fd
831 let mut iov = [IoSlice::new(b"")];
832 let mut msg: libc::msghdr = mem::zeroed();
833
834 msg.msg_iov = (&raw mut iov) as *mut _;
835 msg.msg_iovlen = 1;
836
837 // only attach cmsg if we successfully acquired the pidfd
838 if pidfd >= 0 {
839 msg.msg_controllen = size_of_val(&cmsg.buf) as _;
840 msg.msg_control = (&raw mut cmsg.buf) as *mut _;
841
842 let hdr = CMSG_FIRSTHDR((&raw mut msg) as *mut _);
843 (*hdr).cmsg_level = SOL_SOCKET;
844 (*hdr).cmsg_type = SCM_RIGHTS;
845 (*hdr).cmsg_len = CMSG_LEN(SCM_MSG_LEN as _) as _;
846 let data = CMSG_DATA(hdr);
847 crate::ptr::copy_nonoverlapping(
848 fds.as_ptr().cast::<u8>(),
849 data as *mut _,
850 SCM_MSG_LEN,
851 );
852 }
853
854 // we send the 0-length message even if we failed to acquire the pidfd
855 // so we get a consistent SEQPACKET order
856 match cvt_r(|| libc::sendmsg(sock.as_raw(), &msg, 0)) {
857 Ok(0) => {}
858 other => rtabort!("failed to communicate with parent process. {:?}", other),
859 }
860 }
861 }
862
863 #[cfg(target_os = "linux")]
864 fn recv_pidfd(&self, sock: &crate::sys::net::Socket) -> pid_t {
865 use libc::{CMSG_DATA, CMSG_FIRSTHDR, CMSG_LEN, CMSG_SPACE, SCM_RIGHTS, SOL_SOCKET};
866
867 use crate::io::IoSliceMut;
868 use crate::sys::cvt_r;
869
870 unsafe {
871 const SCM_MSG_LEN: usize = size_of::<[c_int; 1]>();
872
873 #[repr(C)]
874 union Cmsg {
875 _buf: [u8; unsafe { CMSG_SPACE(SCM_MSG_LEN as u32) as usize }],
876 _align: libc::cmsghdr,
877 }
878 let mut cmsg: Cmsg = mem::zeroed();
879 // 0-length read to get the fd
880 let mut iov = [IoSliceMut::new(&mut [])];
881
882 let mut msg: libc::msghdr = mem::zeroed();
883
884 msg.msg_iov = (&raw mut iov) as *mut _;
885 msg.msg_iovlen = 1;
886 msg.msg_controllen = size_of::<Cmsg>() as _;
887 msg.msg_control = (&raw mut cmsg) as *mut _;
888
889 match cvt_r(|| libc::recvmsg(sock.as_raw(), &mut msg, libc::MSG_CMSG_CLOEXEC)) {
890 Err(_) => return -1,
891 Ok(_) => {}
892 }
893
894 let hdr = CMSG_FIRSTHDR((&raw mut msg) as *mut _);
895 if hdr.is_null()
896 || (*hdr).cmsg_level != SOL_SOCKET
897 || (*hdr).cmsg_type != SCM_RIGHTS
898 || (*hdr).cmsg_len != CMSG_LEN(SCM_MSG_LEN as _) as _
899 {
900 return -1;
901 }
902 let data = CMSG_DATA(hdr);
903
904 let mut fds = [-1 as c_int];
905
906 crate::ptr::copy_nonoverlapping(
907 data as *const _,
908 fds.as_mut_ptr().cast::<u8>(),
909 SCM_MSG_LEN,
910 );
911
912 fds[0]
913 }
914 }
915}
916
917////////////////////////////////////////////////////////////////////////////////
918// Processes
919////////////////////////////////////////////////////////////////////////////////
920
921/// The unique ID of the process (this should never be negative).
922pub struct Process {
923 pid: pid_t,
924 status: Option<ExitStatus>,
925 // On Linux, stores the pidfd created for this child.
926 // This is None if the user did not request pidfd creation,
927 // or if the pidfd could not be created for some reason
928 // (e.g. the `pidfd_open` syscall was not available).
929 #[cfg(target_os = "linux")]
930 pidfd: Option<PidFd>,
931}
932
933impl Process {
934 #[cfg(target_os = "linux")]
935 /// # Safety
936 ///
937 /// `pidfd` must either be -1 (representing no file descriptor) or a valid, exclusively owned file
938 /// descriptor (See [I/O Safety]).
939 ///
940 /// [I/O Safety]: crate::io#io-safety
941 unsafe fn new(pid: pid_t, pidfd: pid_t) -> Self {
942 use crate::os::unix::io::FromRawFd;
943 use crate::sys_common::FromInner;
944 // Safety: If `pidfd` is nonnegative, we assume it's valid and otherwise unowned.
945 let pidfd = (pidfd >= 0).then(|| PidFd::from_inner(sys::fd::FileDesc::from_raw_fd(pidfd)));
946 Process { pid, status: None, pidfd }
947 }
948
949 #[cfg(not(target_os = "linux"))]
950 unsafe fn new(pid: pid_t, _pidfd: pid_t) -> Self {
951 Process { pid, status: None }
952 }
953
954 pub fn id(&self) -> u32 {
955 self.pid as u32
956 }
957
958 pub fn kill(&mut self) -> io::Result<()> {
959 // If we've already waited on this process then the pid can be recycled
960 // and used for another process, and we probably shouldn't be killing
961 // random processes, so return Ok because the process has exited already.
962 if self.status.is_some() {
963 return Ok(());
964 }
965 #[cfg(target_os = "linux")]
966 if let Some(pid_fd) = self.pidfd.as_ref() {
967 // pidfd_send_signal predates pidfd_open. so if we were able to get an fd then sending signals will work too
968 return pid_fd.kill();
969 }
970 cvt(unsafe { libc::kill(self.pid, libc::SIGKILL) }).map(drop)
971 }
972
973 pub fn wait(&mut self) -> io::Result<ExitStatus> {
974 use crate::sys::cvt_r;
975 if let Some(status) = self.status {
976 return Ok(status);
977 }
978 #[cfg(target_os = "linux")]
979 if let Some(pid_fd) = self.pidfd.as_ref() {
980 let status = pid_fd.wait()?;
981 self.status = Some(status);
982 return Ok(status);
983 }
984 let mut status = 0 as c_int;
985 cvt_r(|| unsafe { libc::waitpid(self.pid, &mut status, 0) })?;
986 self.status = Some(ExitStatus::new(status));
987 Ok(ExitStatus::new(status))
988 }
989
990 pub fn try_wait(&mut self) -> io::Result<Option<ExitStatus>> {
991 if let Some(status) = self.status {
992 return Ok(Some(status));
993 }
994 #[cfg(target_os = "linux")]
995 if let Some(pid_fd) = self.pidfd.as_ref() {
996 let status = pid_fd.try_wait()?;
997 if let Some(status) = status {
998 self.status = Some(status)
999 }
1000 return Ok(status);
1001 }
1002 let mut status = 0 as c_int;
1003 let pid = cvt(unsafe { libc::waitpid(self.pid, &mut status, libc::WNOHANG) })?;
1004 if pid == 0 {
1005 Ok(None)
1006 } else {
1007 self.status = Some(ExitStatus::new(status));
1008 Ok(Some(ExitStatus::new(status)))
1009 }
1010 }
1011}
1012
1013/// Unix exit statuses
1014//
1015// This is not actually an "exit status" in Unix terminology. Rather, it is a "wait status".
1016// See the discussion in comments and doc comments for `std::process::ExitStatus`.
1017#[derive(PartialEq, Eq, Clone, Copy, Default)]
1018pub struct ExitStatus(c_int);
1019
1020impl fmt::Debug for ExitStatus {
1021 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1022 f.debug_tuple(name:"unix_wait_status").field(&self.0).finish()
1023 }
1024}
1025
1026impl ExitStatus {
1027 pub fn new(status: c_int) -> ExitStatus {
1028 ExitStatus(status)
1029 }
1030
1031 #[cfg(target_os = "linux")]
1032 pub fn from_waitid_siginfo(siginfo: libc::siginfo_t) -> ExitStatus {
1033 let status = unsafe { siginfo.si_status() };
1034
1035 match siginfo.si_code {
1036 libc::CLD_EXITED => ExitStatus((status & 0xff) << 8),
1037 libc::CLD_KILLED => ExitStatus(status),
1038 libc::CLD_DUMPED => ExitStatus(status | 0x80),
1039 libc::CLD_CONTINUED => ExitStatus(0xffff),
1040 libc::CLD_STOPPED | libc::CLD_TRAPPED => ExitStatus(((status & 0xff) << 8) | 0x7f),
1041 _ => unreachable!("waitid() should only return the above codes"),
1042 }
1043 }
1044
1045 fn exited(&self) -> bool {
1046 libc::WIFEXITED(self.0)
1047 }
1048
1049 pub fn exit_ok(&self) -> Result<(), ExitStatusError> {
1050 // This assumes that WIFEXITED(status) && WEXITSTATUS==0 corresponds to status==0. This is
1051 // true on all actual versions of Unix, is widely assumed, and is specified in SuS
1052 // https://pubs.opengroup.org/onlinepubs/9699919799/functions/wait.html. If it is not
1053 // true for a platform pretending to be Unix, the tests (our doctests, and also
1054 // unix/tests.rs) will spot it. `ExitStatusError::code` assumes this too.
1055 match NonZero::try_from(self.0) {
1056 /* was nonzero */ Ok(failure) => Err(ExitStatusError(failure)),
1057 /* was zero, couldn't convert */ Err(_) => Ok(()),
1058 }
1059 }
1060
1061 pub fn code(&self) -> Option<i32> {
1062 self.exited().then(|| libc::WEXITSTATUS(self.0))
1063 }
1064
1065 pub fn signal(&self) -> Option<i32> {
1066 libc::WIFSIGNALED(self.0).then(|| libc::WTERMSIG(self.0))
1067 }
1068
1069 pub fn core_dumped(&self) -> bool {
1070 libc::WIFSIGNALED(self.0) && libc::WCOREDUMP(self.0)
1071 }
1072
1073 pub fn stopped_signal(&self) -> Option<i32> {
1074 libc::WIFSTOPPED(self.0).then(|| libc::WSTOPSIG(self.0))
1075 }
1076
1077 pub fn continued(&self) -> bool {
1078 libc::WIFCONTINUED(self.0)
1079 }
1080
1081 pub fn into_raw(&self) -> c_int {
1082 self.0
1083 }
1084}
1085
1086/// Converts a raw `c_int` to a type-safe `ExitStatus` by wrapping it without copying.
1087impl From<c_int> for ExitStatus {
1088 fn from(a: c_int) -> ExitStatus {
1089 ExitStatus(a)
1090 }
1091}
1092
1093/// Converts a signal number to a readable, searchable name.
1094///
1095/// This string should be displayed right after the signal number.
1096/// If a signal is unrecognized, it returns the empty string, so that
1097/// you just get the number like "0". If it is recognized, you'll get
1098/// something like "9 (SIGKILL)".
1099fn signal_string(signal: i32) -> &'static str {
1100 match signal {
1101 libc::SIGHUP => " (SIGHUP)",
1102 libc::SIGINT => " (SIGINT)",
1103 libc::SIGQUIT => " (SIGQUIT)",
1104 libc::SIGILL => " (SIGILL)",
1105 libc::SIGTRAP => " (SIGTRAP)",
1106 libc::SIGABRT => " (SIGABRT)",
1107 #[cfg(not(target_os = "l4re"))]
1108 libc::SIGBUS => " (SIGBUS)",
1109 libc::SIGFPE => " (SIGFPE)",
1110 libc::SIGKILL => " (SIGKILL)",
1111 #[cfg(not(target_os = "l4re"))]
1112 libc::SIGUSR1 => " (SIGUSR1)",
1113 libc::SIGSEGV => " (SIGSEGV)",
1114 #[cfg(not(target_os = "l4re"))]
1115 libc::SIGUSR2 => " (SIGUSR2)",
1116 libc::SIGPIPE => " (SIGPIPE)",
1117 libc::SIGALRM => " (SIGALRM)",
1118 libc::SIGTERM => " (SIGTERM)",
1119 #[cfg(not(target_os = "l4re"))]
1120 libc::SIGCHLD => " (SIGCHLD)",
1121 #[cfg(not(target_os = "l4re"))]
1122 libc::SIGCONT => " (SIGCONT)",
1123 #[cfg(not(target_os = "l4re"))]
1124 libc::SIGSTOP => " (SIGSTOP)",
1125 #[cfg(not(target_os = "l4re"))]
1126 libc::SIGTSTP => " (SIGTSTP)",
1127 #[cfg(not(target_os = "l4re"))]
1128 libc::SIGTTIN => " (SIGTTIN)",
1129 #[cfg(not(target_os = "l4re"))]
1130 libc::SIGTTOU => " (SIGTTOU)",
1131 #[cfg(not(target_os = "l4re"))]
1132 libc::SIGURG => " (SIGURG)",
1133 #[cfg(not(target_os = "l4re"))]
1134 libc::SIGXCPU => " (SIGXCPU)",
1135 #[cfg(not(any(target_os = "l4re", target_os = "rtems")))]
1136 libc::SIGXFSZ => " (SIGXFSZ)",
1137 #[cfg(not(any(target_os = "l4re", target_os = "rtems")))]
1138 libc::SIGVTALRM => " (SIGVTALRM)",
1139 #[cfg(not(target_os = "l4re"))]
1140 libc::SIGPROF => " (SIGPROF)",
1141 #[cfg(not(any(target_os = "l4re", target_os = "rtems")))]
1142 libc::SIGWINCH => " (SIGWINCH)",
1143 #[cfg(not(any(target_os = "haiku", target_os = "l4re")))]
1144 libc::SIGIO => " (SIGIO)",
1145 #[cfg(target_os = "haiku")]
1146 libc::SIGPOLL => " (SIGPOLL)",
1147 #[cfg(not(target_os = "l4re"))]
1148 libc::SIGSYS => " (SIGSYS)",
1149 // For information on Linux signals, run `man 7 signal`
1150 #[cfg(all(
1151 target_os = "linux",
1152 any(
1153 target_arch = "x86_64",
1154 target_arch = "x86",
1155 target_arch = "arm",
1156 target_arch = "aarch64"
1157 )
1158 ))]
1159 libc::SIGSTKFLT => " (SIGSTKFLT)",
1160 #[cfg(any(target_os = "linux", target_os = "nto", target_os = "cygwin"))]
1161 libc::SIGPWR => " (SIGPWR)",
1162 #[cfg(any(
1163 target_os = "freebsd",
1164 target_os = "netbsd",
1165 target_os = "openbsd",
1166 target_os = "dragonfly",
1167 target_os = "nto",
1168 target_vendor = "apple",
1169 target_os = "cygwin",
1170 ))]
1171 libc::SIGEMT => " (SIGEMT)",
1172 #[cfg(any(
1173 target_os = "freebsd",
1174 target_os = "netbsd",
1175 target_os = "openbsd",
1176 target_os = "dragonfly",
1177 target_vendor = "apple",
1178 ))]
1179 libc::SIGINFO => " (SIGINFO)",
1180 #[cfg(target_os = "hurd")]
1181 libc::SIGLOST => " (SIGLOST)",
1182 #[cfg(target_os = "freebsd")]
1183 libc::SIGTHR => " (SIGTHR)",
1184 #[cfg(target_os = "freebsd")]
1185 libc::SIGLIBRT => " (SIGLIBRT)",
1186 _ => "",
1187 }
1188}
1189
1190impl fmt::Display for ExitStatus {
1191 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1192 if let Some(code: i32) = self.code() {
1193 write!(f, "exit status: {code}")
1194 } else if let Some(signal: i32) = self.signal() {
1195 let signal_string: &'static str = signal_string(signal);
1196 if self.core_dumped() {
1197 write!(f, "signal: {signal}{signal_string} (core dumped)")
1198 } else {
1199 write!(f, "signal: {signal}{signal_string}")
1200 }
1201 } else if let Some(signal: i32) = self.stopped_signal() {
1202 let signal_string: &'static str = signal_string(signal);
1203 write!(f, "stopped (not terminated) by signal: {signal}{signal_string}")
1204 } else if self.continued() {
1205 write!(f, "continued (WIFCONTINUED)")
1206 } else {
1207 write!(f, "unrecognised wait status: {} {:#x}", self.0, self.0)
1208 }
1209 }
1210}
1211
1212#[derive(PartialEq, Eq, Clone, Copy)]
1213pub struct ExitStatusError(NonZero<c_int>);
1214
1215impl Into<ExitStatus> for ExitStatusError {
1216 fn into(self) -> ExitStatus {
1217 ExitStatus(self.0.into())
1218 }
1219}
1220
1221impl fmt::Debug for ExitStatusError {
1222 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1223 f.debug_tuple(name:"unix_wait_status").field(&self.0).finish()
1224 }
1225}
1226
1227impl ExitStatusError {
1228 pub fn code(self) -> Option<NonZero<i32>> {
1229 ExitStatus(self.0.into()).code().map(|st: i32| st.try_into().unwrap())
1230 }
1231}
1232
1233#[cfg(target_os = "linux")]
1234mod linux_child_ext {
1235 use crate::io::ErrorKind;
1236 use crate::os::linux::process as os;
1237 use crate::sys::pal::linux::pidfd as imp;
1238 use crate::sys_common::FromInner;
1239 use crate::{io, mem};
1240
1241 #[unstable(feature = "linux_pidfd", issue = "82971")]
1242 impl crate::os::linux::process::ChildExt for crate::process::Child {
1243 fn pidfd(&self) -> io::Result<&os::PidFd> {
1244 self.handle
1245 .pidfd
1246 .as_ref()
1247 // SAFETY: The os type is a transparent wrapper, therefore we can transmute references
1248 .map(|fd| unsafe { mem::transmute::<&imp::PidFd, &os::PidFd>(fd) })
1249 .ok_or_else(|| io::const_error!(ErrorKind::Uncategorized, "no pidfd was created."))
1250 }
1251
1252 fn into_pidfd(mut self) -> Result<os::PidFd, Self> {
1253 self.handle
1254 .pidfd
1255 .take()
1256 .map(|fd| <os::PidFd as FromInner<imp::PidFd>>::from_inner(fd))
1257 .ok_or_else(|| self)
1258 }
1259 }
1260}
1261
1262#[cfg(test)]
1263mod tests;
1264
1265// See [`unsupported_wait_status::compare_with_linux`];
1266#[cfg(all(test, target_os = "linux"))]
1267#[path = "unsupported/wait_status.rs"]
1268mod unsupported_wait_status;
1269