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std/os/unix/
process.rs

1//! Unix-specific extensions to primitives in the [`std::process`] module.
2//!
3//! [`std::process`]: crate::process
4
5#![stable(feature = "rust1", since = "1.0.0")]
6
7use crate::ffi::OsStr;
8use crate::os::unix::io::{AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, OwnedFd, RawFd};
9use crate::path::Path;
10#[cfg(doc)]
11use crate::process::{ExitStatus, ExitStatusError};
12use crate::sys::process::ChildPipe;
13use crate::sys::{AsInner, AsInnerMut, FromInner, IntoInner};
14use crate::{io, process, sys};
15
16cfg_select! {
17    any(target_os = "vxworks", target_os = "espidf", target_os = "horizon", target_os = "vita") => {
18        type UserId = u16;
19        type GroupId = u16;
20    }
21    any(target_os = "nto", target_os = "qnx") => {
22        // Both IDs are signed, see `sys/target_nto.h` of the QNX Neutrino SDP.
23        // Only positive values should be used, see e.g.
24        // https://www.qnx.com/developers/docs/7.1/#com.qnx.doc.neutrino.lib_ref/topic/s/setuid.html
25        type UserId = i32;
26        type GroupId = i32;
27    }
28    _ => {
29        type UserId = u32;
30        type GroupId = u32;
31    }
32}
33
34/// Unix-specific extensions to the [`process::Command`] builder.
35#[stable(feature = "rust1", since = "1.0.0")]
36pub impl(self) trait CommandExt {
37    /// Sets the child process's user ID. This translates to a
38    /// `setuid` call in the child process. Failure in the `setuid`
39    /// call will cause the spawn to fail.
40    ///
41    /// # Notes
42    ///
43    /// This will also trigger a call to `setgroups(0, NULL)` in the child
44    /// process if no groups have been specified.
45    /// This removes supplementary groups that might have given the child
46    /// unwanted permissions.
47    #[stable(feature = "rust1", since = "1.0.0")]
48    fn uid(&mut self, id: UserId) -> &mut process::Command;
49
50    /// Similar to `uid`, but sets the group ID of the child process. This has
51    /// the same semantics as the `uid` field.
52    #[stable(feature = "rust1", since = "1.0.0")]
53    fn gid(&mut self, id: GroupId) -> &mut process::Command;
54
55    /// Sets the supplementary group IDs for the calling process. Translates to
56    /// a `setgroups` call in the child process.
57    #[unstable(feature = "setgroups", issue = "90747")]
58    fn groups(&mut self, groups: &[GroupId]) -> &mut process::Command;
59
60    /// Schedules a closure to be run just before the `exec` function is
61    /// invoked.
62    ///
63    /// The closure is allowed to return an I/O error whose OS error code will
64    /// be communicated back to the parent and returned as an error from when
65    /// the spawn was requested.
66    ///
67    /// Multiple closures can be registered and they will be called in order of
68    /// their registration. If a closure returns `Err` then no further closures
69    /// will be called and the spawn operation will immediately return with a
70    /// failure.
71    ///
72    /// # Notes and Safety
73    ///
74    /// This closure will be run in the context of the child process after a
75    /// `fork`. This primarily means that any modifications made to memory on
76    /// behalf of this closure will **not** be visible to the parent process.
77    /// This is often a very constrained environment where normal operations
78    /// like `malloc`, accessing environment variables through [`std::env`]
79    /// or acquiring a mutex are not guaranteed to work (due to
80    /// other threads perhaps still running when the `fork` was run).
81    ///
82    /// Note that the list of allocating functions includes [`Error::new`] and
83    /// [`Error::other`]. To signal a non-trivial error, prefer [`panic!`].
84    ///
85    /// For further details refer to the [POSIX fork() specification]
86    /// and the equivalent documentation for any targeted
87    /// platform, especially the requirements around *async-signal-safety*.
88    ///
89    /// This also means that all resources such as file descriptors and
90    /// memory-mapped regions got duplicated. It is your responsibility to make
91    /// sure that the closure does not violate library invariants by making
92    /// invalid use of these duplicates.
93    ///
94    /// Panicking in the closure is safe only if all the format arguments for the
95    /// panic message can be safely formatted; this is because although
96    /// `Command` calls [`std::panic::always_abort`](crate::panic::always_abort)
97    /// before calling the pre_exec hook, panic will still try to format the
98    /// panic message.
99    ///
100    /// When this closure is run, aspects such as the stdio file descriptors and
101    /// working directory have successfully been changed, so output to these
102    /// locations might not appear where intended.
103    ///
104    /// [POSIX fork() specification]:
105    ///     https://pubs.opengroup.org/onlinepubs/9699919799/functions/fork.html
106    /// [`std::env`]: mod@crate::env
107    /// [`Error::new`]: ../../../io/struct.Error.html#method.new
108    /// [`Error::other`]: ../../../io/struct.Error.html#method.other
109    #[stable(feature = "process_pre_exec", since = "1.34.0")]
110    unsafe fn pre_exec<F>(&mut self, f: F) -> &mut process::Command
111    where
112        F: FnMut() -> io::Result<()> + Send + Sync + 'static;
113
114    /// Schedules a closure to be run just before the `exec` function is
115    /// invoked.
116    ///
117    /// `before_exec` used to be a safe method, but it needs to be unsafe since the closure may only
118    /// perform operations that are *async-signal-safe*. Hence it got deprecated in favor of the
119    /// unsafe [`pre_exec`]. Meanwhile, Rust gained the ability to make an existing safe method
120    /// fully unsafe in a new edition, which is how `before_exec` became `unsafe`. It still also
121    /// remains deprecated; `pre_exec` should be used instead.
122    ///
123    /// [`pre_exec`]: CommandExt::pre_exec
124    #[stable(feature = "process_exec", since = "1.15.0")]
125    #[deprecated(since = "1.37.0", note = "should be unsafe, use `pre_exec` instead")]
126    #[rustc_deprecated_safe_2024(audit_that = "the closure is async-signal-safe")]
127    unsafe fn before_exec<F>(&mut self, f: F) -> &mut process::Command
128    where
129        F: FnMut() -> io::Result<()> + Send + Sync + 'static,
130    {
131        unsafe { self.pre_exec(f) }
132    }
133
134    /// Performs all the required setup by this `Command`, followed by calling
135    /// the `execvp` syscall.
136    ///
137    /// On success this function will not return, and otherwise it will return
138    /// an error indicating why the exec (or another part of the setup of the
139    /// `Command`) failed.
140    ///
141    /// `exec` not returning has the same implications as calling
142    /// [`process::exit`] – no destructors on the current stack or any other
143    /// thread’s stack will be run. Therefore, it is recommended to only call
144    /// `exec` at a point where it is fine to not run any destructors. Note,
145    /// that the `execvp` syscall independently guarantees that all memory is
146    /// freed and all file descriptors with the `CLOEXEC` option (set by default
147    /// on all file descriptors opened by the standard library) are closed.
148    ///
149    /// This function, unlike `spawn`, will **not** `fork` the process to create
150    /// a new child. Like spawn, however, the default behavior for the stdio
151    /// descriptors will be to inherit them from the current process.
152    ///
153    /// # Notes
154    ///
155    /// The process may be in a "broken state" if this function returns in
156    /// error. For example the working directory, environment variables, signal
157    /// handling settings, various user/group information, or aspects of stdio
158    /// file descriptors may have changed. If a "transactional spawn" is
159    /// required to gracefully handle errors it is recommended to use the
160    /// cross-platform `spawn` instead.
161    #[stable(feature = "process_exec2", since = "1.9.0")]
162    #[must_use]
163    fn exec(&mut self) -> io::Error;
164
165    /// Set executable argument
166    ///
167    /// Set the first process argument, `argv[0]`, to something other than the
168    /// default executable path.
169    #[stable(feature = "process_set_argv0", since = "1.45.0")]
170    fn arg0<S>(&mut self, arg: S) -> &mut process::Command
171    where
172        S: AsRef<OsStr>;
173
174    /// Sets the process group ID (PGID) of the child process. Equivalent to a
175    /// `setpgid` call in the child process, but may be more efficient.
176    ///
177    /// Process groups determine which processes receive signals.
178    ///
179    /// # Examples
180    ///
181    /// Pressing Ctrl-C in a terminal will send SIGINT to all processes in
182    /// the current foreground process group. By spawning the `sleep`
183    /// subprocess in a new process group, it will not receive SIGINT from the
184    /// terminal.
185    ///
186    /// The parent process could install a signal handler and manage the
187    /// subprocess on its own terms.
188    ///
189    /// A process group ID of 0 will use the process ID as the PGID.
190    ///
191    /// ```no_run
192    /// use std::process::Command;
193    /// use std::os::unix::process::CommandExt;
194    ///
195    /// Command::new("sleep")
196    ///     .arg("10")
197    ///     .process_group(0)
198    ///     .spawn()?
199    ///     .wait()?;
200    /// #
201    /// # Ok::<_, Box<dyn std::error::Error>>(())
202    /// ```
203    #[stable(feature = "process_set_process_group", since = "1.64.0")]
204    fn process_group(&mut self, pgroup: i32) -> &mut process::Command;
205
206    /// Set the root of the child process. This calls `chroot` in the child process before executing
207    /// the command.
208    ///
209    /// This happens before changing to the directory specified with
210    /// [`process::Command::current_dir`], and that directory will be relative to the new root.
211    ///
212    /// If no directory has been specified with [`process::Command::current_dir`], this will set the
213    /// directory to `/`, to avoid leaving the current directory outside the chroot. (This is an
214    /// intentional difference from the underlying `chroot` system call.)
215    #[unstable(feature = "process_chroot", issue = "141298")]
216    fn chroot<P: AsRef<Path>>(&mut self, dir: P) -> &mut process::Command;
217
218    #[unstable(feature = "process_setsid", issue = "105376")]
219    fn setsid(&mut self, setsid: bool) -> &mut process::Command;
220}
221
222#[stable(feature = "rust1", since = "1.0.0")]
223impl CommandExt for process::Command {
224    fn uid(&mut self, id: UserId) -> &mut process::Command {
225        self.as_inner_mut().uid(id);
226        self
227    }
228
229    fn gid(&mut self, id: GroupId) -> &mut process::Command {
230        self.as_inner_mut().gid(id);
231        self
232    }
233
234    fn groups(&mut self, groups: &[GroupId]) -> &mut process::Command {
235        self.as_inner_mut().groups(groups);
236        self
237    }
238
239    unsafe fn pre_exec<F>(&mut self, f: F) -> &mut process::Command
240    where
241        F: FnMut() -> io::Result<()> + Send + Sync + 'static,
242    {
243        self.as_inner_mut().pre_exec(Box::new(f));
244        self
245    }
246
247    fn exec(&mut self) -> io::Error {
248        // NOTE: This may *not* be safe to call after `libc::fork`, because it
249        // may allocate. That may be worth fixing at some point in the future.
250        self.as_inner_mut().exec(sys::process::Stdio::Inherit)
251    }
252
253    fn arg0<S>(&mut self, arg: S) -> &mut process::Command
254    where
255        S: AsRef<OsStr>,
256    {
257        self.as_inner_mut().set_arg_0(arg.as_ref());
258        self
259    }
260
261    fn process_group(&mut self, pgroup: i32) -> &mut process::Command {
262        self.as_inner_mut().pgroup(pgroup);
263        self
264    }
265
266    fn chroot<P: AsRef<Path>>(&mut self, dir: P) -> &mut process::Command {
267        self.as_inner_mut().chroot(dir.as_ref());
268        self
269    }
270
271    fn setsid(&mut self, setsid: bool) -> &mut process::Command {
272        self.as_inner_mut().setsid(setsid);
273        self
274    }
275}
276
277/// Unix-specific extensions to [`ExitStatus`] and [`ExitStatusError`].
278///
279/// On Unix, [`ExitStatus`] **does not necessarily represent an exit status**, as
280/// passed to the `_exit` system call or returned by
281/// [`ExitStatus::code()`](ExitStatus::code).  It represents **any wait status**
282/// as returned by one of the [`wait`] family of system
283/// calls.
284///
285/// A Unix wait status (a Rust [`ExitStatus`]) can represent a Unix exit status, but can also
286/// represent other kinds of process event.
287///
288/// [`wait`]: https://pubs.opengroup.org/onlinepubs/9799919799/functions/wait.html
289#[stable(feature = "rust1", since = "1.0.0")]
290pub impl(self) trait ExitStatusExt {
291    /// Creates a new [`ExitStatus`] or [`ExitStatusError`] from the raw underlying integer status
292    /// value from [`wait`].
293    ///
294    /// The value should be a **wait status, not an exit status**.
295    ///
296    /// # Example
297    ///
298    /// A signal-terminated [`wait`] status carries the signal number, which [`ExitStatus::signal`]
299    /// recovers using the platform's [`WTERMSIG`][`wait`] macro. Note that the bit layout of a
300    /// wait status is **not** specified by POSIX and is platform-specific. By convention on most
301    /// Unix platforms, the signal number occupies the low 7 bits with the exit-code byte left
302    /// zero, so a bare signal number between 1 and 126 is treated as a signal-terminated wait
303    /// status. The following example relies on that convention and is therefore not guaranteed to
304    /// hold on every target:
305    ///
306    /// ```
307    /// # if cfg!(target_os = "fuchsia") { return; }
308    /// use std::os::unix::process::ExitStatusExt;
309    /// use std::process::ExitStatus;
310    ///
311    /// let signal = 15; // SIGTERM
312    /// assert!(signal > 0 && signal < 0x7f, "not a valid Unix termination signal: {signal}");
313    ///
314    /// let status = ExitStatus::from_raw(signal);
315    /// assert!(!status.success());
316    /// assert_eq!(status.code(), None);
317    /// assert_eq!(status.signal(), Some(15));
318    /// ```
319    ///
320    /// Generating an [`ExitStatus`] with a given exit code (0-255) is system-dependent.
321    /// The value returned by [`ExitStatus::code`] is specified to come from applying the
322    /// [`WEXITSTATUS`][`wait`] macro, but there is no POSIX-specified constructor and the bit
323    /// layout is left unspecified. By near-universal convention every Unix libc stores the
324    /// 8-bit exit code in bits 8..16, so a status built with `(code & 0xff) << 8` will usually
325    /// round-trip back to the original exit code:
326    ///
327    /// ```
328    /// # if cfg!(target_os = "fuchsia") { return; }
329    /// use std::os::unix::process::ExitStatusExt;
330    /// use std::process::ExitStatus;
331    ///
332    /// let code = 41;
333    /// let status = ExitStatus::from_raw((code & 0xff) << 8);
334    /// assert_eq!(status.code(), Some(41));
335    /// assert!(!status.success());
336    /// ```
337    ///
338    /// # Panics
339    ///
340    /// - `ExitStatusError::from_raw` panics on an attempt to make an [`ExitStatusError`] from a
341    ///    [`wait`] status of `0`.
342    /// - `ExitStatus::from_raw` always succeeds and never panics.
343    ///
344    /// [`wait`]: https://pubs.opengroup.org/onlinepubs/9799919799/functions/wait.html
345    #[stable(feature = "exit_status_from", since = "1.12.0")]
346    fn from_raw(raw: i32) -> Self;
347
348    /// If the process was terminated by a signal, returns that signal.
349    ///
350    /// In other words, if [`WIFSIGNALED`][`wait`], this returns [`WTERMSIG`][`wait`]. For such a status,
351    /// [`ExitStatus::code`] returns `None`:
352    ///
353    /// ```
354    /// # if cfg!(target_os = "fuchsia") { return; }
355    /// use std::os::unix::process::ExitStatusExt;
356    /// use std::process::ExitStatus;
357    ///
358    /// let sigterm = 15;
359    /// let status = ExitStatus::from_raw(sigterm);
360    /// assert_eq!(status.code(), None);
361    /// assert_eq!(status.signal(), Some(sigterm));
362    /// ```
363    ///
364    /// A process that receives a signal may catch and handle it, then exit normally with an
365    /// exit code. When that happens, `signal` returns `None`.
366    ///
367    /// Rust does not pass commands through a shell, such as `bash` and `sh`, but it
368    /// is possible to do so manually. When invoking a shell, the signal value indicates whether
369    /// the top-level shell itself received a terminating signal. If instead a command *within*
370    /// an invoked shell receives a terminating signal, many shells convert the signal number
371    /// into an exit code by adding 128. For example, a command run under `sh` that receives a
372    /// [`SIGTERM`] canonically causes the shell to report an exit code of `15 + 128`, i.e. `143`.
373    ///
374    /// [`SIGTERM`]: https://pubs.opengroup.org/onlinepubs/9799919799/utilities/kill.html
375    /// [`wait`]: https://pubs.opengroup.org/onlinepubs/9799919799/functions/wait.html
376    #[stable(feature = "rust1", since = "1.0.0")]
377    fn signal(&self) -> Option<i32>;
378
379    /// If the process was terminated by a signal, says whether it dumped core.
380    #[stable(feature = "unix_process_wait_more", since = "1.58.0")]
381    fn core_dumped(&self) -> bool;
382
383    /// If the process was stopped by a signal, returns that signal.
384    ///
385    /// In other words, if [`WIFSTOPPED`][`wait`], this returns [`WSTOPSIG`][`wait`].  This is only possible if the status came from
386    /// a [`wait`] system call which was passed [`WUNTRACED`][`wait`], and was then converted into an [`ExitStatus`].
387    ///
388    /// [`wait`]: https://pubs.opengroup.org/onlinepubs/9799919799/functions/wait.html
389    #[stable(feature = "unix_process_wait_more", since = "1.58.0")]
390    fn stopped_signal(&self) -> Option<i32>;
391
392    /// Whether the process was continued from a stopped status.
393    ///
394    /// I.e. [`WIFCONTINUED`][`wait`].  This is only possible if the status came from a [`wait`] system call
395    /// which was passed [`WCONTINUED`][`wait`], and was then converted into an [`ExitStatus`].
396    ///
397    /// [`wait`]: https://pubs.opengroup.org/onlinepubs/9799919799/functions/wait.html
398    #[stable(feature = "unix_process_wait_more", since = "1.58.0")]
399    fn continued(&self) -> bool;
400
401    /// Returns the underlying raw [`wait`] status.
402    ///
403    /// The returned integer is a **wait status, not an exit status**.
404    ///
405    /// [`wait`]: https://pubs.opengroup.org/onlinepubs/9799919799/functions/wait.html
406    #[stable(feature = "unix_process_wait_more", since = "1.58.0")]
407    fn into_raw(self) -> i32;
408}
409
410#[stable(feature = "rust1", since = "1.0.0")]
411impl ExitStatusExt for process::ExitStatus {
412    fn from_raw(raw: i32) -> Self {
413        process::ExitStatus::from_inner(From::from(raw))
414    }
415
416    fn signal(&self) -> Option<i32> {
417        self.as_inner().signal()
418    }
419
420    fn core_dumped(&self) -> bool {
421        self.as_inner().core_dumped()
422    }
423
424    fn stopped_signal(&self) -> Option<i32> {
425        self.as_inner().stopped_signal()
426    }
427
428    fn continued(&self) -> bool {
429        self.as_inner().continued()
430    }
431
432    fn into_raw(self) -> i32 {
433        self.as_inner().into_raw().into()
434    }
435}
436
437#[unstable(feature = "exit_status_error", issue = "84908")]
438impl ExitStatusExt for process::ExitStatusError {
439    fn from_raw(raw: i32) -> Self {
440        process::ExitStatus::from_raw(raw)
441            .exit_ok()
442            .expect_err("<ExitStatusError as ExitStatusExt>::from_raw(0) but zero is not an error")
443    }
444
445    fn signal(&self) -> Option<i32> {
446        self.into_status().signal()
447    }
448
449    fn core_dumped(&self) -> bool {
450        self.into_status().core_dumped()
451    }
452
453    fn stopped_signal(&self) -> Option<i32> {
454        self.into_status().stopped_signal()
455    }
456
457    fn continued(&self) -> bool {
458        self.into_status().continued()
459    }
460
461    fn into_raw(self) -> i32 {
462        self.into_status().into_raw()
463    }
464}
465
466#[unstable(feature = "unix_send_signal", issue = "141975")]
467pub impl(self) trait ChildExt {
468    /// Sends a signal to a child process.
469    ///
470    /// # Errors
471    ///
472    /// This function will return an error if the signal is invalid. The integer values associated
473    /// with signals are implementation-specific, so it's encouraged to use a crate that provides
474    /// posix bindings.
475    ///
476    /// # Examples
477    ///
478    /// ```rust
479    /// #![feature(unix_send_signal)]
480    ///
481    /// use std::{io, os::unix::process::ChildExt, process::{Command, Stdio}};
482    ///
483    /// use libc::SIGTERM;
484    ///
485    /// fn main() -> io::Result<()> {
486    ///     # if cfg!(not(all(target_vendor = "apple", not(target_os = "macos")))) {
487    ///     let child = Command::new("cat").stdin(Stdio::piped()).spawn()?;
488    ///     child.send_signal(SIGTERM)?;
489    ///     # }
490    ///     Ok(())
491    /// }
492    /// ```
493    fn send_signal(&self, signal: i32) -> io::Result<()>;
494
495    /// Sends a signal to a child process's process group.
496    ///
497    /// # Errors
498    ///
499    /// This function will return an error if the signal is invalid or if the
500    /// child process does not have a process group. The integer values
501    /// associated with signals are implementation-specific, so it's encouraged
502    /// to use a crate that provides posix bindings.
503    ///
504    /// # Examples
505    ///
506    /// ```rust
507    /// #![feature(unix_send_signal)]
508    ///
509    /// use std::{io, os::unix::process::{ChildExt, CommandExt}, process::{Command, Stdio}};
510    ///
511    /// use libc::SIGTERM;
512    ///
513    /// fn main() -> io::Result<()> {
514    ///     # if cfg!(not(all(target_vendor = "apple", not(target_os = "macos")))) {
515    ///     let child = Command::new("cat")
516    ///         .stdin(Stdio::piped())
517    ///         .process_group(0)
518    ///         .spawn()?;
519    ///     child.send_process_group_signal(SIGTERM)?;
520    ///     # }
521    ///     Ok(())
522    /// }
523    /// ```
524    #[unstable(feature = "unix_send_signal", issue = "141975")]
525    fn send_process_group_signal(&self, signal: i32) -> io::Result<()>;
526
527    /// Forces the child process's process group to exit.
528    ///
529    /// This is analogous to [`Child::kill`] but applies to every process in
530    /// the child process's process group.
531    ///
532    /// Use [`CommandExt::process_group`] to assign a child process to an
533    /// existing process group, or to make it the leader of a new process group.
534    /// By default spawned processes are in the parent's process group.
535    ///
536    /// # Examples
537    ///
538    /// ```rust
539    /// #![feature(unix_kill_process_group)]
540    ///
541    /// use std::{os::unix::process::{ChildExt, CommandExt}, process::{Command, Stdio}};
542    ///
543    /// fn main() -> std::io::Result<()> {
544    ///     let mut child = Command::new("cat")
545    ///         .stdin(Stdio::piped())
546    ///         .process_group(0)
547    ///         .spawn()?;
548    ///     child.kill_process_group()?;
549    ///     Ok(())
550    /// }
551    /// ```
552    ///
553    /// [`Child::kill`]: process::Child::kill
554    #[unstable(feature = "unix_kill_process_group", issue = "156537")]
555    fn kill_process_group(&mut self) -> io::Result<()>;
556}
557
558#[unstable(feature = "unix_send_signal", issue = "141975")]
559impl ChildExt for process::Child {
560    fn send_signal(&self, signal: i32) -> io::Result<()> {
561        self.handle.send_signal(signal)
562    }
563
564    fn send_process_group_signal(&self, signal: i32) -> io::Result<()> {
565        self.handle.send_process_group_signal(signal)
566    }
567
568    #[cfg(not(target_os = "espidf"))]
569    fn kill_process_group(&mut self) -> io::Result<()> {
570        self.handle.send_process_group_signal(libc::SIGKILL)
571    }
572
573    #[cfg(target_os = "espidf")]
574    fn kill_process_group(&mut self) -> io::Result<()> {
575        Err(io::Error::new(
576            io::ErrorKind::Unsupported,
577            "process groups are not supported on espidf",
578        ))
579    }
580}
581
582#[stable(feature = "process_extensions", since = "1.2.0")]
583impl FromRawFd for process::Stdio {
584    #[inline]
585    unsafe fn from_raw_fd(fd: RawFd) -> process::Stdio {
586        let fd = sys::fd::FileDesc::from_raw_fd(fd);
587        let io = sys::process::Stdio::Fd(fd);
588        process::Stdio::from_inner(io)
589    }
590}
591
592#[stable(feature = "io_safety", since = "1.63.0")]
593impl From<OwnedFd> for process::Stdio {
594    /// Takes ownership of a file descriptor and returns a [`Stdio`](process::Stdio)
595    /// that can attach a stream to it.
596    #[inline]
597    fn from(fd: OwnedFd) -> process::Stdio {
598        let fd = sys::fd::FileDesc::from_inner(fd);
599        let io = sys::process::Stdio::Fd(fd);
600        process::Stdio::from_inner(io)
601    }
602}
603
604#[stable(feature = "process_extensions", since = "1.2.0")]
605impl AsRawFd for process::ChildStdin {
606    #[inline]
607    fn as_raw_fd(&self) -> RawFd {
608        self.as_inner().as_raw_fd()
609    }
610}
611
612#[stable(feature = "process_extensions", since = "1.2.0")]
613impl AsRawFd for process::ChildStdout {
614    #[inline]
615    fn as_raw_fd(&self) -> RawFd {
616        self.as_inner().as_raw_fd()
617    }
618}
619
620#[stable(feature = "process_extensions", since = "1.2.0")]
621impl AsRawFd for process::ChildStderr {
622    #[inline]
623    fn as_raw_fd(&self) -> RawFd {
624        self.as_inner().as_raw_fd()
625    }
626}
627
628#[stable(feature = "into_raw_os", since = "1.4.0")]
629impl IntoRawFd for process::ChildStdin {
630    #[inline]
631    fn into_raw_fd(self) -> RawFd {
632        self.into_inner().into_inner().into_raw_fd()
633    }
634}
635
636#[stable(feature = "into_raw_os", since = "1.4.0")]
637impl IntoRawFd for process::ChildStdout {
638    #[inline]
639    fn into_raw_fd(self) -> RawFd {
640        self.into_inner().into_inner().into_raw_fd()
641    }
642}
643
644#[stable(feature = "into_raw_os", since = "1.4.0")]
645impl IntoRawFd for process::ChildStderr {
646    #[inline]
647    fn into_raw_fd(self) -> RawFd {
648        self.into_inner().into_inner().into_raw_fd()
649    }
650}
651
652#[stable(feature = "io_safety", since = "1.63.0")]
653impl AsFd for crate::process::ChildStdin {
654    #[inline]
655    fn as_fd(&self) -> BorrowedFd<'_> {
656        self.as_inner().as_fd()
657    }
658}
659
660#[stable(feature = "io_safety", since = "1.63.0")]
661impl From<crate::process::ChildStdin> for OwnedFd {
662    /// Takes ownership of a [`ChildStdin`](crate::process::ChildStdin)'s file descriptor.
663    #[inline]
664    fn from(child_stdin: crate::process::ChildStdin) -> OwnedFd {
665        child_stdin.into_inner().into_inner()
666    }
667}
668
669/// Creates a `ChildStdin` from the provided `OwnedFd`.
670///
671/// The provided file descriptor must point to a pipe
672/// with the `CLOEXEC` flag set.
673#[stable(feature = "child_stream_from_fd", since = "1.74.0")]
674impl From<OwnedFd> for process::ChildStdin {
675    #[inline]
676    fn from(fd: OwnedFd) -> process::ChildStdin {
677        let pipe = ChildPipe::from_inner(fd);
678        process::ChildStdin::from_inner(pipe)
679    }
680}
681
682#[stable(feature = "io_safety", since = "1.63.0")]
683impl AsFd for crate::process::ChildStdout {
684    #[inline]
685    fn as_fd(&self) -> BorrowedFd<'_> {
686        self.as_inner().as_fd()
687    }
688}
689
690#[stable(feature = "io_safety", since = "1.63.0")]
691impl From<crate::process::ChildStdout> for OwnedFd {
692    /// Takes ownership of a [`ChildStdout`](crate::process::ChildStdout)'s file descriptor.
693    #[inline]
694    fn from(child_stdout: crate::process::ChildStdout) -> OwnedFd {
695        child_stdout.into_inner().into_inner()
696    }
697}
698
699/// Creates a `ChildStdout` from the provided `OwnedFd`.
700///
701/// The provided file descriptor must point to a pipe
702/// with the `CLOEXEC` flag set.
703#[stable(feature = "child_stream_from_fd", since = "1.74.0")]
704impl From<OwnedFd> for process::ChildStdout {
705    #[inline]
706    fn from(fd: OwnedFd) -> process::ChildStdout {
707        let pipe = ChildPipe::from_inner(fd);
708        process::ChildStdout::from_inner(pipe)
709    }
710}
711
712#[stable(feature = "io_safety", since = "1.63.0")]
713impl AsFd for crate::process::ChildStderr {
714    #[inline]
715    fn as_fd(&self) -> BorrowedFd<'_> {
716        self.as_inner().as_fd()
717    }
718}
719
720#[stable(feature = "io_safety", since = "1.63.0")]
721impl From<crate::process::ChildStderr> for OwnedFd {
722    /// Takes ownership of a [`ChildStderr`](crate::process::ChildStderr)'s file descriptor.
723    #[inline]
724    fn from(child_stderr: crate::process::ChildStderr) -> OwnedFd {
725        child_stderr.into_inner().into_inner()
726    }
727}
728
729/// Creates a `ChildStderr` from the provided `OwnedFd`.
730///
731/// The provided file descriptor must point to a pipe
732/// with the `CLOEXEC` flag set.
733#[stable(feature = "child_stream_from_fd", since = "1.74.0")]
734impl From<OwnedFd> for process::ChildStderr {
735    #[inline]
736    fn from(fd: OwnedFd) -> process::ChildStderr {
737        let pipe = ChildPipe::from_inner(fd);
738        process::ChildStderr::from_inner(pipe)
739    }
740}
741
742/// Returns the OS-assigned process identifier associated with this process's parent.
743#[must_use]
744#[stable(feature = "unix_ppid", since = "1.27.0")]
745pub fn parent_id() -> u32 {
746    crate::sys::process::getppid()
747}