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rust/rust/3b917841b0cfefff70368f3feb7abc8f896d9bd1/./library/std/src/process.rs
blob: 0b8db439a63707214f5e0f9b60d80dd93145e7b7 [file]
//! A module for working with processes.
//!
//! This module is mostly concerned with spawning and interacting with child
//! processes, but it also provides [`abort`] and [`exit`] for terminating the
//! current process.
//!
//! # Spawning a process
//!
//! The [`Command`] struct is used to configure and spawn processes:
//!
//! ```no_run
//! use std::process::Command;
//!
//! let output = Command::new("echo")
//! .arg("Hello world")
//! .output()
//! .expect("Failed to execute command");
//!
//! assert_eq!(b"Hello world\n", output.stdout.as_slice());
//! ```
//!
//! Several methods on [`Command`], such as [`spawn`] or [`output`], can be used
//! to spawn a process. In particular, [`output`] spawns the child process and
//! waits until the process terminates, while [`spawn`] will return a [`Child`]
//! that represents the spawned child process.
//!
//! # Handling I/O
//!
//! The [`stdout`], [`stdin`], and [`stderr`] of a child process can be
//! configured by passing an [`Stdio`] to the corresponding method on
//! [`Command`]. Once spawned, they can be accessed from the [`Child`]. For
//! example, piping output from one command into another command can be done
//! like so:
//!
//! ```no_run
//! use std::process::{Command, Stdio};
//!
//! // stdout must be configured with `Stdio::piped` in order to use
//! // `echo_child.stdout`
//! let echo_child = Command::new("echo")
//! .arg("Oh no, a tpyo!")
//! .stdout(Stdio::piped())
//! .spawn()
//! .expect("Failed to start echo process");
//!
//! // Note that `echo_child` is moved here, but we won't be needing
//! // `echo_child` anymore
//! let echo_out = echo_child.stdout.expect("Failed to open echo stdout");
//!
//! let mut sed_child = Command::new("sed")
//! .arg("s/tpyo/typo/")
//! .stdin(Stdio::from(echo_out))
//! .stdout(Stdio::piped())
//! .spawn()
//! .expect("Failed to start sed process");
//!
//! let output = sed_child.wait_with_output().expect("Failed to wait on sed");
//! assert_eq!(b"Oh no, a typo!\n", output.stdout.as_slice());
//! ```
//!
//! Note that [`ChildStderr`] and [`ChildStdout`] implement [`Read`] and
//! [`ChildStdin`] implements [`Write`]:
//!
//! ```no_run
//! use std::process::{Command, Stdio};
//! use std::io::Write;
//!
//! let mut child = Command::new("/bin/cat")
//! .stdin(Stdio::piped())
//! .stdout(Stdio::piped())
//! .spawn()
//! .expect("failed to execute child");
//!
//! // If the child process fills its stdout buffer, it may end up
//! // waiting until the parent reads the stdout, and not be able to
//! // read stdin in the meantime, causing a deadlock.
//! // Writing from another thread ensures that stdout is being read
//! // at the same time, avoiding the problem.
//! let mut stdin = child.stdin.take().expect("failed to get stdin");
//! std::thread::spawn(move || {
//! stdin.write_all(b"test").expect("failed to write to stdin");
//! });
//!
//! let output = child
//! .wait_with_output()
//! .expect("failed to wait on child");
//!
//! assert_eq!(b"test", output.stdout.as_slice());
//! ```
//!
//! # Windows argument splitting
//!
//! On Unix systems arguments are passed to a new process as an array of strings,
//! but on Windows arguments are passed as a single commandline string and it is
//! up to the child process to parse it into an array. Therefore the parent and
//! child processes must agree on how the commandline string is encoded.
//!
//! Most programs use the standard C run-time `argv`, which in practice results
//! in consistent argument handling. However, some programs have their own way of
//! parsing the commandline string. In these cases using [`arg`] or [`args`] may
//! result in the child process seeing a different array of arguments than the
//! parent process intended.
//!
//! Two ways of mitigating this are:
//!
//! * Validate untrusted input so that only a safe subset is allowed.
//! * Use [`raw_arg`] to build a custom commandline. This bypasses the escaping
//! rules used by [`arg`] so should be used with due caution.
//!
//! `cmd.exe` and `.bat` files use non-standard argument parsing and are especially
//! vulnerable to malicious input as they may be used to run arbitrary shell
//! commands. Untrusted arguments should be restricted as much as possible.
//! For examples on handling this see [`raw_arg`].
//!
//! ### Batch file special handling
//!
//! On Windows, `Command` uses the Windows API function [`CreateProcessW`] to
//! spawn new processes. An undocumented feature of this function is that
//! when given a `.bat` file as the application to run, it will automatically
//! convert that into running `cmd.exe /c` with the batch file as the next argument.
//!
//! For historical reasons Rust currently preserves this behavior when using
//! [`Command::new`], and escapes the arguments according to `cmd.exe` rules.
//! Due to the complexity of `cmd.exe` argument handling, it might not be
//! possible to safely escape some special characters, and using them will result
//! in an error being returned at process spawn. The set of unescapeable
//! special characters might change between releases.
//!
//! Also note that running batch scripts in this way may be removed in the
//! future and so should not be relied upon.
//!
//! [`spawn`]: Command::spawn
//! [`output`]: Command::output
//!
//! [`stdout`]: Command::stdout
//! [`stdin`]: Command::stdin
//! [`stderr`]: Command::stderr
//!
//! [`Write`]: io::Write
//! [`Read`]: io::Read
//!
//! [`arg`]: Command::arg
//! [`args`]: Command::args
//! [`raw_arg`]: crate::os::windows::process::CommandExt::raw_arg
//!
//! [`CreateProcessW`]: https://learn.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-createprocessw
#![stable(feature = "process", since = "1.0.0")]
#![deny(unsafe_op_in_unsafe_fn)]
#[cfg(all(
test,
not(any(
target_os = "emscripten",
target_os = "wasi",
target_env = "sgx",
target_os = "xous",
target_os = "trusty",
target_os = "hermit",
))
))]
mod tests;
use crate::convert::Infallible;
use crate::ffi::OsStr;
use crate::io::prelude::*;
use crate::io::{self, BorrowedCursor, IoSlice, IoSliceMut};
use crate::num::NonZero;
use crate::path::Path;
use crate::sys::{AsInner, AsInnerMut, FromInner, IntoInner, process as imp};
use crate::{fmt, format_args_nl, fs, str};
/// Representation of a running or exited child process.
///
/// This structure is used to represent and manage child processes. A child
/// process is created via the [`Command`] struct, which configures the
/// spawning process and can itself be constructed using a builder-style
/// interface.
///
/// There is no implementation of [`Drop`] for child processes,
/// so if you do not ensure the `Child` has exited then it will continue to
/// run, even after the `Child` handle to the child process has gone out of
/// scope.
///
/// Calling [`wait`] (or other functions that wrap around it) will make
/// the parent process wait until the child has actually exited before
/// continuing.
///
/// # Warning
///
/// On some systems, calling [`wait`] or similar is necessary for the OS to
/// release resources. A process that terminated but has not been waited on is
/// still around as a "zombie". Leaving too many zombies around may exhaust
/// global resources (for example process IDs).
///
/// The standard library does *not* automatically wait on child processes (not
/// even if the `Child` is dropped), it is up to the application developer to do
/// so. As a consequence, dropping `Child` handles without waiting on them first
/// is not recommended in long-running applications.
///
/// # Examples
///
/// ```should_panic
/// use std::process::Command;
///
/// let mut child = Command::new("/bin/cat")
/// .arg("file.txt")
/// .spawn()
/// .expect("failed to execute child");
///
/// let ecode = child.wait().expect("failed to wait on child");
///
/// assert!(ecode.success());
/// ```
///
/// [`wait`]: Child::wait
#[stable(feature = "process", since = "1.0.0")]
#[cfg_attr(not(test), rustc_diagnostic_item = "Child")]
pub struct Child {
pub(crate) handle: imp::Process,
/// The handle for writing to the child's standard input (stdin), if it
/// has been captured. You might find it helpful to do
///
/// ```ignore (incomplete)
/// let stdin = child.stdin.take().expect("handle present");
/// ```
///
/// to avoid partially moving the `child` and thus blocking yourself from calling
/// functions on `child` while using `stdin`.
#[stable(feature = "process", since = "1.0.0")]
pub stdin: Option<ChildStdin>,
/// The handle for reading from the child's standard output (stdout), if it
/// has been captured. You might find it helpful to do
///
/// ```ignore (incomplete)
/// let stdout = child.stdout.take().expect("handle present");
/// ```
///
/// to avoid partially moving the `child` and thus blocking yourself from calling
/// functions on `child` while using `stdout`.
#[stable(feature = "process", since = "1.0.0")]
pub stdout: Option<ChildStdout>,
/// The handle for reading from the child's standard error (stderr), if it
/// has been captured. You might find it helpful to do
///
/// ```ignore (incomplete)
/// let stderr = child.stderr.take().expect("handle present");
/// ```
///
/// to avoid partially moving the `child` and thus blocking yourself from calling
/// functions on `child` while using `stderr`.
#[stable(feature = "process", since = "1.0.0")]
pub stderr: Option<ChildStderr>,
}
/// Allows extension traits within `std`.
#[unstable(feature = "sealed", issue = "none")]
impl crate::sealed::Sealed for Child {}
impl AsInner<imp::Process> for Child {
#[inline]
fn as_inner(&self) -> &imp::Process {
&self.handle
}
}
impl FromInner<(imp::Process, StdioPipes)> for Child {
fn from_inner((handle, io): (imp::Process, StdioPipes)) -> Child {
Child {
handle,
stdin: io.stdin.map(ChildStdin::from_inner),
stdout: io.stdout.map(ChildStdout::from_inner),
stderr: io.stderr.map(ChildStderr::from_inner),
}
}
}
impl IntoInner<imp::Process> for Child {
fn into_inner(self) -> imp::Process {
self.handle
}
}
#[stable(feature = "std_debug", since = "1.16.0")]
impl fmt::Debug for Child {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("Child")
.field("stdin", &self.stdin)
.field("stdout", &self.stdout)
.field("stderr", &self.stderr)
.finish_non_exhaustive()
}
}
/// The pipes connected to a spawned process.
///
/// Used to pass pipe handles between this module and [`imp`].
pub(crate) struct StdioPipes {
pub stdin: Option<imp::ChildPipe>,
pub stdout: Option<imp::ChildPipe>,
pub stderr: Option<imp::ChildPipe>,
}
/// A handle to a child process's standard input (stdin).
///
/// This struct is used in the [`stdin`] field on [`Child`].
///
/// When an instance of `ChildStdin` is [dropped], the `ChildStdin`'s underlying
/// file handle will be closed. If the child process was blocked on input prior
/// to being dropped, it will become unblocked after dropping.
///
/// [`stdin`]: Child::stdin
/// [dropped]: Drop
#[stable(feature = "process", since = "1.0.0")]
pub struct ChildStdin {
inner: imp::ChildPipe,
}
// In addition to the `impl`s here, `ChildStdin` also has `impl`s for
// `AsFd`/`From<OwnedFd>`/`Into<OwnedFd>` and
// `AsRawFd`/`IntoRawFd`/`FromRawFd`, on Unix and WASI, and
// `AsHandle`/`From<OwnedHandle>`/`Into<OwnedHandle>` and
// `AsRawHandle`/`IntoRawHandle`/`FromRawHandle` on Windows.
#[stable(feature = "process", since = "1.0.0")]
impl Write for ChildStdin {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
(&*self).write(buf)
}
fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
(&*self).write_vectored(bufs)
}
fn is_write_vectored(&self) -> bool {
io::Write::is_write_vectored(&&*self)
}
#[inline]
fn flush(&mut self) -> io::Result<()> {
(&*self).flush()
}
}
#[stable(feature = "write_mt", since = "1.48.0")]
impl Write for &ChildStdin {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
self.inner.write(buf)
}
fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
self.inner.write_vectored(bufs)
}
fn is_write_vectored(&self) -> bool {
self.inner.is_write_vectored()
}
#[inline]
fn flush(&mut self) -> io::Result<()> {
Ok(())
}
}
impl AsInner<imp::ChildPipe> for ChildStdin {
#[inline]
fn as_inner(&self) -> &imp::ChildPipe {
&self.inner
}
}
impl IntoInner<imp::ChildPipe> for ChildStdin {
fn into_inner(self) -> imp::ChildPipe {
self.inner
}
}
impl FromInner<imp::ChildPipe> for ChildStdin {
fn from_inner(pipe: imp::ChildPipe) -> ChildStdin {
ChildStdin { inner: pipe }
}
}
#[stable(feature = "std_debug", since = "1.16.0")]
impl fmt::Debug for ChildStdin {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("ChildStdin").finish_non_exhaustive()
}
}
/// A handle to a child process's standard output (stdout).
///
/// This struct is used in the [`stdout`] field on [`Child`].
///
/// When an instance of `ChildStdout` is [dropped], the `ChildStdout`'s
/// underlying file handle will be closed.
///
/// [`stdout`]: Child::stdout
/// [dropped]: Drop
#[stable(feature = "process", since = "1.0.0")]
pub struct ChildStdout {
inner: imp::ChildPipe,
}
// In addition to the `impl`s here, `ChildStdout` also has `impl`s for
// `AsFd`/`From<OwnedFd>`/`Into<OwnedFd>` and
// `AsRawFd`/`IntoRawFd`/`FromRawFd`, on Unix and WASI, and
// `AsHandle`/`From<OwnedHandle>`/`Into<OwnedHandle>` and
// `AsRawHandle`/`IntoRawHandle`/`FromRawHandle` on Windows.
#[stable(feature = "process", since = "1.0.0")]
impl Read for ChildStdout {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
self.inner.read(buf)
}
fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> io::Result<()> {
self.inner.read_buf(buf)
}
fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
self.inner.read_vectored(bufs)
}
#[inline]
fn is_read_vectored(&self) -> bool {
self.inner.is_read_vectored()
}
fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
self.inner.read_to_end(buf)
}
}
impl AsInner<imp::ChildPipe> for ChildStdout {
#[inline]
fn as_inner(&self) -> &imp::ChildPipe {
&self.inner
}
}
impl IntoInner<imp::ChildPipe> for ChildStdout {
fn into_inner(self) -> imp::ChildPipe {
self.inner
}
}
impl FromInner<imp::ChildPipe> for ChildStdout {
fn from_inner(pipe: imp::ChildPipe) -> ChildStdout {
ChildStdout { inner: pipe }
}
}
#[stable(feature = "std_debug", since = "1.16.0")]
impl fmt::Debug for ChildStdout {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("ChildStdout").finish_non_exhaustive()
}
}
/// A handle to a child process's stderr.
///
/// This struct is used in the [`stderr`] field on [`Child`].
///
/// When an instance of `ChildStderr` is [dropped], the `ChildStderr`'s
/// underlying file handle will be closed.
///
/// [`stderr`]: Child::stderr
/// [dropped]: Drop
#[stable(feature = "process", since = "1.0.0")]
pub struct ChildStderr {
inner: imp::ChildPipe,
}
// In addition to the `impl`s here, `ChildStderr` also has `impl`s for
// `AsFd`/`From<OwnedFd>`/`Into<OwnedFd>` and
// `AsRawFd`/`IntoRawFd`/`FromRawFd`, on Unix and WASI, and
// `AsHandle`/`From<OwnedHandle>`/`Into<OwnedHandle>` and
// `AsRawHandle`/`IntoRawHandle`/`FromRawHandle` on Windows.
#[stable(feature = "process", since = "1.0.0")]
impl Read for ChildStderr {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
self.inner.read(buf)
}
fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> io::Result<()> {
self.inner.read_buf(buf)
}
fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
self.inner.read_vectored(bufs)
}
#[inline]
fn is_read_vectored(&self) -> bool {
self.inner.is_read_vectored()
}
fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
self.inner.read_to_end(buf)
}
}
impl AsInner<imp::ChildPipe> for ChildStderr {
#[inline]
fn as_inner(&self) -> &imp::ChildPipe {
&self.inner
}
}
impl IntoInner<imp::ChildPipe> for ChildStderr {
fn into_inner(self) -> imp::ChildPipe {
self.inner
}
}
impl FromInner<imp::ChildPipe> for ChildStderr {
fn from_inner(pipe: imp::ChildPipe) -> ChildStderr {
ChildStderr { inner: pipe }
}
}
#[stable(feature = "std_debug", since = "1.16.0")]
impl fmt::Debug for ChildStderr {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("ChildStderr").finish_non_exhaustive()
}
}
/// A process builder, providing fine-grained control
/// over how a new process should be spawned.
///
/// A default configuration can be
/// generated using `Command::new(program)`, where `program` gives a path to the
/// program to be executed. Additional builder methods allow the configuration
/// to be changed (for example, by adding arguments) prior to spawning:
///
/// ```
/// # if cfg!(not(all(target_vendor = "apple", not(target_os = "macos")))) {
/// use std::process::Command;
///
/// let output = if cfg!(target_os = "windows") {
/// Command::new("cmd")
/// .args(["/C", "echo hello"])
/// .output()
/// .expect("failed to execute process")
/// } else {
/// Command::new("sh")
/// .arg("-c")
/// .arg("echo hello")
/// .output()
/// .expect("failed to execute process")
/// };
///
/// let hello = output.stdout;
/// # }
/// ```
///
/// `Command` can be reused to spawn multiple processes. The builder methods
/// change the command without needing to immediately spawn the process.
///
/// ```no_run
/// use std::process::Command;
///
/// let mut echo_hello = Command::new("sh");
/// echo_hello.arg("-c").arg("echo hello");
/// let hello_1 = echo_hello.output().expect("failed to execute process");
/// let hello_2 = echo_hello.output().expect("failed to execute process");
/// ```
///
/// Similarly, you can call builder methods after spawning a process and then
/// spawn a new process with the modified settings.
///
/// ```no_run
/// use std::process::Command;
///
/// let mut list_dir = Command::new("ls");
///
/// // Execute `ls` in the current directory of the program.
/// list_dir.status().expect("process failed to execute");
///
/// println!();
///
/// // Change `ls` to execute in the root directory.
/// list_dir.current_dir("/");
///
/// // And then execute `ls` again but in the root directory.
/// list_dir.status().expect("process failed to execute");
/// ```
#[stable(feature = "process", since = "1.0.0")]
#[cfg_attr(not(test), rustc_diagnostic_item = "Command")]
pub struct Command {
inner: imp::Command,
}
/// Allows extension traits within `std`.
#[unstable(feature = "sealed", issue = "none")]
impl crate::sealed::Sealed for Command {}
impl Command {
/// Constructs a new `Command` for launching the program at
/// path `program`, with the following default configuration:
///
/// * No arguments to the program
/// * Inherit the current process's environment
/// * Inherit the current process's working directory
/// * Inherit stdin/stdout/stderr for [`spawn`] or [`status`], but create pipes for [`output`]
///
/// [`spawn`]: Self::spawn
/// [`status`]: Self::status
/// [`output`]: Self::output
///
/// Builder methods are provided to change these defaults and
/// otherwise configure the process.
///
/// If `program` is not an absolute path, the `PATH` environment variable
/// will be searched in an OS-defined way.
///
/// # Platform-specific behavior
///
/// The details below describe the current behavior, but these details
/// may change in future versions of Rust.
///
/// On Unix, the `PATH` searched comes from the child's environment:
///
/// - If the environment is unmodified, the child inherits the parent's
/// `PATH` and that is what is searched.
/// - If `PATH` is explicitly set via [`env`], that new value is searched.
/// - If [`env_clear`] or [`env_remove`] removes `PATH` without a
/// replacement, `execvp` falls back to an OS-defined default (typically
/// `/bin:/usr/bin`), **not** the parent's `PATH`. This may fail to find
/// programs that rely on the parent's `PATH`.
///
/// To avoid surprises, use an absolute path or explicitly set `PATH` on
/// the `Command` when modifying the child's environment.
///
/// On Windows, Rust resolves the executable path before spawning, rather
/// than passing the name to `CreateProcessW` for resolution. When
/// `program` is not an absolute path, the following locations are searched
/// in order:
///
/// 1. The child's `PATH`, if explicitly set via [`env`].
/// 2. The directory of the current executable.
/// 3. The system directory (`GetSystemDirectoryW`).
/// 4. The Windows directory (`GetWindowsDirectoryW`).
/// 5. The parent process's `PATH`.
///
/// Note: when `PATH` is cleared via [`env_clear`] or [`env_remove`] on
/// Windows, step 1 is skipped but the parent process's `PATH` is still
/// searched at step 5, unlike on Unix.
///
/// For executable files, the `.exe` extension may be omitted. Files with
/// other extensions must include the extension, otherwise they will not be
/// found. Note that this behavior has some known limitations
/// (see issue #37519).
///
/// [`env`]: Self::env
/// [`env_remove`]: Self::env_remove
/// [`env_clear`]: Self::env_clear
///
/// # Examples
///
/// ```no_run
/// use std::process::Command;
///
/// Command::new("sh")
/// .spawn()
/// .expect("sh command failed to start");
/// ```
///
/// # Caveats
///
/// [`Command::new`] is only intended to accept the path of the program. If you pass a program
/// path along with arguments like `Command::new("ls -l").spawn()`, it will try to search for
/// `ls -l` literally. The arguments need to be passed separately, such as via [`arg`] or
/// [`args`].
///
/// ```no_run
/// use std::process::Command;
///
/// Command::new("ls")
/// .arg("-l") // arg passed separately
/// .spawn()
/// .expect("ls command failed to start");
/// ```
///
/// [`arg`]: Self::arg
/// [`args`]: Self::args
#[stable(feature = "process", since = "1.0.0")]
pub fn new<S: AsRef<OsStr>>(program: S) -> Command {
Command { inner: imp::Command::new(program.as_ref()) }
}
/// Adds an argument to pass to the program.
///
/// Only one argument can be passed per use. So instead of:
///
/// ```no_run
/// # std::process::Command::new("sh")
/// .arg("-C /path/to/repo")
/// # ;
/// ```
///
/// usage would be:
///
/// ```no_run
/// # std::process::Command::new("sh")
/// .arg("-C")
/// .arg("/path/to/repo")
/// # ;
/// ```
///
/// To pass multiple arguments see [`args`].
///
/// [`args`]: Command::args
///
/// Note that the argument is not passed through a shell, but given
/// literally to the program. This means that shell syntax like quotes,
/// escaped characters, word splitting, glob patterns, variable substitution,
/// etc. have no effect.
///
/// <div class="warning">
///
/// On Windows, use caution with untrusted inputs. Most applications use the
/// standard convention for decoding arguments passed to them. These are safe to
/// use with `arg`. However, some applications such as `cmd.exe` and `.bat` files
/// use a non-standard way of decoding arguments. They are therefore vulnerable
/// to malicious input.
///
/// In the case of `cmd.exe` this is especially important because a malicious
/// argument can potentially run arbitrary shell commands.
///
/// See [Windows argument splitting][windows-args] for more details
/// or [`raw_arg`] for manually implementing non-standard argument encoding.
///
/// [`raw_arg`]: crate::os::windows::process::CommandExt::raw_arg
/// [windows-args]: crate::process#windows-argument-splitting
///
/// </div>
///
/// # Examples
///
/// ```no_run
/// use std::process::Command;
///
/// Command::new("ls")
/// .arg("-l")
/// .arg("-a")
/// .spawn()
/// .expect("ls command failed to start");
/// ```
#[stable(feature = "process", since = "1.0.0")]
pub fn arg<S: AsRef<OsStr>>(&mut self, arg: S) -> &mut Command {
self.inner.arg(arg.as_ref());
self
}
/// Adds multiple arguments to pass to the program.
///
/// To pass a single argument see [`arg`].
///
/// [`arg`]: Command::arg
///
/// Note that the arguments are not passed through a shell, but given
/// literally to the program. This means that shell syntax like quotes,
/// escaped characters, word splitting, glob patterns, variable substitution, etc.
/// have no effect.
///
/// <div class="warning">
///
/// On Windows, use caution with untrusted inputs. Most applications use the
/// standard convention for decoding arguments passed to them. These are safe to
/// use with `arg`. However, some applications such as `cmd.exe` and `.bat` files
/// use a non-standard way of decoding arguments. They are therefore vulnerable
/// to malicious input.
///
/// In the case of `cmd.exe` this is especially important because a malicious
/// argument can potentially run arbitrary shell commands.
///
/// See [Windows argument splitting][windows-args] for more details
/// or [`raw_arg`] for manually implementing non-standard argument encoding.
///
/// [`raw_arg`]: crate::os::windows::process::CommandExt::raw_arg
/// [windows-args]: crate::process#windows-argument-splitting
///
/// </div>
///
/// # Examples
///
/// ```no_run
/// use std::process::Command;
///
/// Command::new("ls")
/// .args(["-l", "-a"])
/// .spawn()
/// .expect("ls command failed to start");
/// ```
#[stable(feature = "process", since = "1.0.0")]
pub fn args<I, S>(&mut self, args: I) -> &mut Command
where
I: IntoIterator<Item = S>,
S: AsRef<OsStr>,
{
for arg in args {
self.arg(arg.as_ref());
}
self
}
/// Inserts or updates an explicit environment variable mapping.
///
/// This method allows you to add an environment variable mapping to the spawned process or
/// overwrite a previously set value. You can use [`Command::envs`] to set multiple environment
/// variables simultaneously.
///
/// Child processes will inherit environment variables from their parent process by default.
/// Environment variables explicitly set using [`Command::env`] take precedence over inherited
/// variables. You can disable environment variable inheritance entirely using
/// [`Command::env_clear`] or for a single key using [`Command::env_remove`].
///
/// Note that environment variable names are case-insensitive (but
/// case-preserving) on Windows and case-sensitive on all other platforms.
///
/// # Examples
///
/// ```no_run
/// use std::process::Command;
///
/// Command::new("ls")
/// .env("PATH", "/bin")
/// .spawn()
/// .expect("ls command failed to start");
/// ```
#[stable(feature = "process", since = "1.0.0")]
pub fn env<K, V>(&mut self, key: K, val: V) -> &mut Command
where
K: AsRef<OsStr>,
V: AsRef<OsStr>,
{
self.inner.env_mut().set(key.as_ref(), val.as_ref());
self
}
/// Inserts or updates multiple explicit environment variable mappings.
///
/// This method allows you to add multiple environment variable mappings to the spawned process
/// or overwrite previously set values. You can use [`Command::env`] to set a single environment
/// variable.
///
/// Child processes will inherit environment variables from their parent process by default.
/// Environment variables explicitly set using [`Command::envs`] take precedence over inherited
/// variables. You can disable environment variable inheritance entirely using
/// [`Command::env_clear`] or for a single key using [`Command::env_remove`].
///
/// Note that environment variable names are case-insensitive (but case-preserving) on Windows
/// and case-sensitive on all other platforms.
///
/// # Examples
///
/// ```no_run
/// use std::process::{Command, Stdio};
/// use std::env;
/// use std::collections::HashMap;
///
/// let filtered_env : HashMap<String, String> =
/// env::vars().filter(|&(ref k, _)|
/// k == "TERM" || k == "TZ" || k == "LANG" || k == "PATH"
/// ).collect();
///
/// Command::new("printenv")
/// .stdin(Stdio::null())
/// .stdout(Stdio::inherit())
/// .env_clear()
/// .envs(&filtered_env)
/// .spawn()
/// .expect("printenv failed to start");
/// ```
#[stable(feature = "command_envs", since = "1.19.0")]
pub fn envs<I, K, V>(&mut self, vars: I) -> &mut Command
where
I: IntoIterator<Item = (K, V)>,
K: AsRef<OsStr>,
V: AsRef<OsStr>,
{
for (ref key, ref val) in vars {
self.inner.env_mut().set(key.as_ref(), val.as_ref());
}
self
}
/// Removes an explicitly set environment variable and prevents inheriting it from a parent
/// process.
///
/// This method will remove the explicit value of an environment variable set via
/// [`Command::env`] or [`Command::envs`]. In addition, it will prevent the spawned child
/// process from inheriting that environment variable from its parent process.
///
/// After calling [`Command::env_remove`], the value associated with its key from
/// [`Command::get_envs`] will be [`None`].
///
/// To clear all explicitly set environment variables and disable all environment variable
/// inheritance, you can use [`Command::env_clear`].
///
/// # Examples
///
/// Prevent any inherited `GIT_DIR` variable from changing the target of the `git` command,
/// while allowing all other variables, like `GIT_AUTHOR_NAME`.
///
/// ```no_run
/// use std::process::Command;
///
/// Command::new("git")
/// .arg("commit")
/// .env_remove("GIT_DIR")
/// .spawn()?;
/// # std::io::Result::Ok(())
/// ```
#[stable(feature = "process", since = "1.0.0")]
pub fn env_remove<K: AsRef<OsStr>>(&mut self, key: K) -> &mut Command {
self.inner.env_mut().remove(key.as_ref());
self
}
/// Clears all explicitly set environment variables and prevents inheriting any parent process
/// environment variables.
///
/// This method will remove all explicitly added environment variables set via [`Command::env`]
/// or [`Command::envs`]. In addition, it will prevent the spawned child process from inheriting
/// any environment variable from its parent process.
///
/// After calling [`Command::env_clear`], the iterator from [`Command::get_envs`] will be
/// empty.
///
/// You can use [`Command::env_remove`] to clear a single mapping.
///
/// # Examples
///
/// The behavior of `sort` is affected by `LANG` and `LC_*` environment variables.
/// Clearing the environment makes `sort`'s behavior independent of the parent processes' language.
///
/// ```no_run
/// use std::process::Command;
///
/// Command::new("sort")
/// .arg("file.txt")
/// .env_clear()
/// .spawn()?;
/// # std::io::Result::Ok(())
/// ```
#[stable(feature = "process", since = "1.0.0")]
pub fn env_clear(&mut self) -> &mut Command {
self.inner.env_mut().clear();
self
}
/// Sets the working directory for the child process.
///
/// # Platform-specific behavior
///
/// If the program path is relative (e.g., `"./script.sh"`), it's ambiguous
/// whether it should be interpreted relative to the parent's working
/// directory or relative to `current_dir`. The behavior in this case is
/// platform specific and unstable, and it's recommended to use
/// [`canonicalize`] to get an absolute program path instead.
///
/// # Examples
///
/// ```no_run
/// use std::process::Command;
///
/// Command::new("ls")
/// .current_dir("/bin")
/// .spawn()
/// .expect("ls command failed to start");
/// ```
///
/// [`canonicalize`]: crate::fs::canonicalize
#[stable(feature = "process", since = "1.0.0")]
pub fn current_dir<P: AsRef<Path>>(&mut self, dir: P) -> &mut Command {
self.inner.cwd(dir.as_ref().as_ref());
self
}
/// Configuration for the child process's standard input (stdin) handle.
///
/// Defaults to [`inherit`] when used with [`spawn`] or [`status`], and
/// defaults to [`piped`] when used with [`output`].
///
/// [`inherit`]: Stdio::inherit
/// [`piped`]: Stdio::piped
/// [`spawn`]: Self::spawn
/// [`status`]: Self::status
/// [`output`]: Self::output
///
/// # Examples
///
/// ```no_run
/// use std::process::{Command, Stdio};
///
/// Command::new("ls")
/// .stdin(Stdio::null())
/// .spawn()
/// .expect("ls command failed to start");
/// ```
#[stable(feature = "process", since = "1.0.0")]
pub fn stdin<T: Into<Stdio>>(&mut self, cfg: T) -> &mut Command {
self.inner.stdin(cfg.into().0);
self
}
/// Configuration for the child process's standard output (stdout) handle.
///
/// Defaults to [`inherit`] when used with [`spawn`] or [`status`], and
/// defaults to [`piped`] when used with [`output`].
///
/// [`inherit`]: Stdio::inherit
/// [`piped`]: Stdio::piped
/// [`spawn`]: Self::spawn
/// [`status`]: Self::status
/// [`output`]: Self::output
///
/// # Examples
///
/// ```no_run
/// use std::process::{Command, Stdio};
///
/// Command::new("ls")
/// .stdout(Stdio::null())
/// .spawn()
/// .expect("ls command failed to start");
/// ```
#[stable(feature = "process", since = "1.0.0")]
pub fn stdout<T: Into<Stdio>>(&mut self, cfg: T) -> &mut Command {
self.inner.stdout(cfg.into().0);
self
}
/// Configuration for the child process's standard error (stderr) handle.
///
/// Defaults to [`inherit`] when used with [`spawn`] or [`status`], and
/// defaults to [`piped`] when used with [`output`].
///
/// [`inherit`]: Stdio::inherit
/// [`piped`]: Stdio::piped
/// [`spawn`]: Self::spawn
/// [`status`]: Self::status
/// [`output`]: Self::output
///
/// # Examples
///
/// ```no_run
/// use std::process::{Command, Stdio};
///
/// Command::new("ls")
/// .stderr(Stdio::null())
/// .spawn()
/// .expect("ls command failed to start");
/// ```
#[stable(feature = "process", since = "1.0.0")]
pub fn stderr<T: Into<Stdio>>(&mut self, cfg: T) -> &mut Command {
self.inner.stderr(cfg.into().0);
self
}
/// Executes the command as a child process, returning a handle to it.
///
/// By default, stdin, stdout and stderr are inherited from the parent.
///
/// # Examples
///
/// ```no_run
/// use std::process::Command;
///
/// Command::new("ls")
/// .spawn()
/// .expect("ls command failed to start");
/// ```
#[stable(feature = "process", since = "1.0.0")]
pub fn spawn(&mut self) -> io::Result<Child> {
self.inner.spawn(imp::Stdio::Inherit, true).map(Child::from_inner)
}
/// Executes the command as a child process, waiting for it to finish and
/// collecting all of its output.
///
/// By default, stdout and stderr are captured (and used to provide the
/// resulting output). Stdin is not inherited from the parent and any
/// attempt by the child process to read from the stdin stream will result
/// in the stream immediately closing.
///
/// # Examples
///
/// ```should_panic
/// use std::process::Command;
/// use std::io::{self, Write};
/// let output = Command::new("/bin/cat")
/// .arg("file.txt")
/// .output()?;
///
/// println!("status: {}", output.status);
/// io::stdout().write_all(&output.stdout)?;
/// io::stderr().write_all(&output.stderr)?;
///
/// assert!(output.status.success());
/// # io::Result::Ok(())
/// ```
#[stable(feature = "process", since = "1.0.0")]
pub fn output(&mut self) -> io::Result<Output> {
let (status, stdout, stderr) = imp::output(&mut self.inner)?;
Ok(Output { status: ExitStatus(status), stdout, stderr })
}
/// Executes a command as a child process, waiting for it to finish and
/// collecting its status.
///
/// By default, stdin, stdout and stderr are inherited from the parent.
///
/// # Examples
///
/// ```should_panic
/// use std::process::Command;
///
/// let status = Command::new("/bin/cat")
/// .arg("file.txt")
/// .status()
/// .expect("failed to execute process");
///
/// println!("process finished with: {status}");
///
/// assert!(status.success());
/// ```
#[stable(feature = "process", since = "1.0.0")]
pub fn status(&mut self) -> io::Result<ExitStatus> {
self.inner
.spawn(imp::Stdio::Inherit, true)
.map(Child::from_inner)
.and_then(|mut p| p.wait())
}
/// Returns the path to the program that was given to [`Command::new`].
///
/// # Examples
///
/// ```
/// use std::process::Command;
///
/// let cmd = Command::new("echo");
/// assert_eq!(cmd.get_program(), "echo");
/// ```
#[must_use]
#[stable(feature = "command_access", since = "1.57.0")]
pub fn get_program(&self) -> &OsStr {
self.inner.get_program()
}
/// Returns an iterator of the arguments that will be passed to the program.
///
/// This does not include the path to the program as the first argument;
/// it only includes the arguments specified with [`Command::arg`] and
/// [`Command::args`].
///
/// # Examples
///
/// ```
/// use std::ffi::OsStr;
/// use std::process::Command;
///
/// let mut cmd = Command::new("echo");
/// cmd.arg("first").arg("second");
/// let args: Vec<&OsStr> = cmd.get_args().collect();
/// assert_eq!(args, &["first", "second"]);
/// ```
#[stable(feature = "command_access", since = "1.57.0")]
pub fn get_args(&self) -> CommandArgs<'_> {
CommandArgs { inner: self.inner.get_args() }
}
/// Returns an iterator of the environment variables explicitly set for the child process.
///
/// Environment variables explicitly set using [`Command::env`], [`Command::envs`], and
/// [`Command::env_remove`] can be retrieved with this method.
///
/// Note that this output does not include environment variables inherited from the parent
/// process. To see the full list of environment variables, including those inherited from the
/// parent process, use [`Command::get_resolved_envs`].
///
/// Each element is a tuple key/value pair `(&OsStr, Option<&OsStr>)`. A [`None`] value
/// indicates its key was explicitly removed via [`Command::env_remove`]. The associated key for
/// the [`None`] value will no longer inherit from its parent process.
///
/// An empty iterator can indicate that no explicit mappings were added or that
/// [`Command::env_clear`] was called. After calling [`Command::env_clear`], the child process
/// will not inherit any environment variables from its parent process.
///
/// # Examples
///
/// ```
/// use std::ffi::OsStr;
/// use std::process::Command;
///
/// let mut cmd = Command::new("ls");
/// cmd.env("TERM", "dumb").env_remove("TZ");
/// let envs: Vec<(&OsStr, Option<&OsStr>)> = cmd.get_envs().collect();
/// assert_eq!(envs, &[
/// (OsStr::new("TERM"), Some(OsStr::new("dumb"))),
/// (OsStr::new("TZ"), None)
/// ]);
/// ```
#[stable(feature = "command_access", since = "1.57.0")]
pub fn get_envs(&self) -> CommandEnvs<'_> {
CommandEnvs { iter: self.inner.get_envs() }
}
/// Returns an iterator of the environment variables that will be set when the process is spawned.
///
/// This returns the environment as it would be if the command were executed at the time of calling
/// this method. The returned environment includes:
/// - All inherited environment variables from the parent process (unless [`Command::env_clear`] was called)
/// - All environment variables explicitly set via [`Command::env`] or [`Command::envs`]
/// - Excluding any environment variables removed via [`Command::env_remove`]
///
/// Note that the returned environment is a snapshot at the time this method is called and will not
/// reflect any subsequent changes to the `Command` or the parent process's environment. Additionally,
/// it will not reflect changes made in a `pre_exec` hook (on Unix platforms).
///
/// Each element is a tuple `(OsString, OsString)` representing an environment variable key and value.
///
/// # Examples
///
/// ```
/// #![feature(command_resolved_envs)]
/// use std::process::Command;
/// use std::ffi::{OsString, OsStr};
/// use std::env;
/// use std::collections::HashMap;
///
/// let mut cmd = Command::new("ls");
/// cmd.env("TZ", "UTC");
/// unsafe { env::set_var("EDITOR", "vim"); }
///
/// let resolved: HashMap<OsString, OsString> = cmd.get_resolved_envs().collect();
/// assert_eq!(resolved.get(OsStr::new("TZ")), Some(&OsString::from("UTC")));
/// assert_eq!(resolved.get(OsStr::new("EDITOR")), Some(&OsString::from("vim")));
/// ```
#[unstable(feature = "command_resolved_envs", issue = "149070")]
pub fn get_resolved_envs(&self) -> CommandResolvedEnvs {
self.inner.get_resolved_envs()
}
/// Returns the working directory for the child process.
///
/// This returns [`None`] if the working directory will not be changed.
///
/// # Examples
///
/// ```
/// use std::path::Path;
/// use std::process::Command;
///
/// let mut cmd = Command::new("ls");
/// assert_eq!(cmd.get_current_dir(), None);
/// cmd.current_dir("/bin");
/// assert_eq!(cmd.get_current_dir(), Some(Path::new("/bin")));
/// ```
#[must_use]
#[stable(feature = "command_access", since = "1.57.0")]
pub fn get_current_dir(&self) -> Option<&Path> {
self.inner.get_current_dir()
}
/// Returns whether the environment will be cleared for the child process.
///
/// This returns `true` if [`Command::env_clear`] was called, and `false` otherwise.
/// When `true`, the child process will not inherit any environment variables from
/// its parent process.
///
/// # Examples
///
/// ```
/// #![feature(command_resolved_envs)]
/// use std::process::Command;
///
/// let mut cmd = Command::new("ls");
/// assert_eq!(cmd.get_env_clear(), false);
///
/// cmd.env_clear();
/// assert_eq!(cmd.get_env_clear(), true);
/// ```
#[must_use]
#[unstable(feature = "command_resolved_envs", issue = "149070")]
pub fn get_env_clear(&self) -> bool {
self.inner.get_env_clear()
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl fmt::Debug for Command {
/// Format the program and arguments of a Command for display. Any
/// non-utf8 data is lossily converted using the utf8 replacement
/// character.
///
/// The default format approximates a shell invocation of the program along with its
/// arguments. It does not include most of the other command properties. The output is not guaranteed to work
/// (e.g. due to lack of shell-escaping or differences in path resolution).
/// On some platforms you can use [the alternate syntax] to show more fields.
///
/// Note that the debug implementation is platform-specific.
///
/// [the alternate syntax]: fmt#sign0
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.inner.fmt(f)
}
}
impl AsInner<imp::Command> for Command {
#[inline]
fn as_inner(&self) -> &imp::Command {
&self.inner
}
}
impl AsInnerMut<imp::Command> for Command {
#[inline]
fn as_inner_mut(&mut self) -> &mut imp::Command {
&mut self.inner
}
}
/// An iterator over the command arguments.
///
/// This struct is created by [`Command::get_args`]. See its documentation for
/// more.
#[must_use = "iterators are lazy and do nothing unless consumed"]
#[stable(feature = "command_access", since = "1.57.0")]
#[derive(Debug)]
pub struct CommandArgs<'a> {
inner: imp::CommandArgs<'a>,
}
#[stable(feature = "command_access", since = "1.57.0")]
impl<'a> Iterator for CommandArgs<'a> {
type Item = &'a OsStr;
fn next(&mut self) -> Option<&'a OsStr> {
self.inner.next()
}
fn size_hint(&self) -> (usize, Option<usize>) {
self.inner.size_hint()
}
}
#[stable(feature = "command_access", since = "1.57.0")]
impl<'a> ExactSizeIterator for CommandArgs<'a> {
fn len(&self) -> usize {
self.inner.len()
}
fn is_empty(&self) -> bool {
self.inner.is_empty()
}
}
/// An iterator over the command environment variables.
///
/// This struct is created by
/// [`Command::get_envs`][crate::process::Command::get_envs]. See its
/// documentation for more.
#[must_use = "iterators are lazy and do nothing unless consumed"]
#[stable(feature = "command_access", since = "1.57.0")]
pub struct CommandEnvs<'a> {
iter: imp::CommandEnvs<'a>,
}
#[stable(feature = "command_access", since = "1.57.0")]
impl<'a> Iterator for CommandEnvs<'a> {
type Item = (&'a OsStr, Option<&'a OsStr>);
fn next(&mut self) -> Option<Self::Item> {
self.iter.next()
}
fn size_hint(&self) -> (usize, Option<usize>) {
self.iter.size_hint()
}
}
#[stable(feature = "command_access", since = "1.57.0")]
impl<'a> ExactSizeIterator for CommandEnvs<'a> {
fn len(&self) -> usize {
self.iter.len()
}
fn is_empty(&self) -> bool {
self.iter.is_empty()
}
}
#[stable(feature = "command_access", since = "1.57.0")]
impl<'a> fmt::Debug for CommandEnvs<'a> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.iter.fmt(f)
}
}
#[unstable(feature = "command_resolved_envs", issue = "149070")]
pub use imp::CommandResolvedEnvs;
/// The output of a finished process.
///
/// This is returned in a Result by either the [`output`] method of a
/// [`Command`], or the [`wait_with_output`] method of a [`Child`]
/// process.
///
/// [`output`]: Command::output
/// [`wait_with_output`]: Child::wait_with_output
#[derive(PartialEq, Eq, Clone)]
#[stable(feature = "process", since = "1.0.0")]
pub struct Output {
/// The status (exit code) of the process.
#[stable(feature = "process", since = "1.0.0")]
pub status: ExitStatus,
/// The data that the process wrote to stdout.
#[stable(feature = "process", since = "1.0.0")]
pub stdout: Vec<u8>,
/// The data that the process wrote to stderr.
#[stable(feature = "process", since = "1.0.0")]
pub stderr: Vec<u8>,
}
impl Output {
/// Returns an error if a nonzero exit status was received.
///
/// If the [`Command`] exited successfully,
/// `self` is returned.
///
/// This is equivalent to calling [`exit_ok`](ExitStatus::exit_ok)
/// on [`Output.status`](Output::status).
///
/// Note that this will throw away the [`Output::stderr`] field in the error case.
/// If the child process outputs useful informantion to stderr, you can:
/// * Use `cmd.stderr(Stdio::inherit())` to forward the
/// stderr child process to the parent's stderr,
/// usually printing it to console where the user can see it.
/// This is usually correct for command-line applications.
/// * Capture `stderr` using a custom error type.
/// This is usually correct for libraries.
///
/// # Examples
///
/// ```
/// # #![allow(unused_features)]
/// #![feature(exit_status_error)]
/// # #[cfg(all(unix, not(target_os = "android"), not(all(target_vendor = "apple", not(target_os = "macos")))))] {
/// use std::process::Command;
/// assert!(Command::new("false").output().unwrap().exit_ok().is_err());
/// # }
/// ```
#[unstable(feature = "exit_status_error", issue = "84908")]
pub fn exit_ok(self) -> Result<Self, ExitStatusError> {
self.status.exit_ok()?;
Ok(self)
}
}
// If either stderr or stdout are valid utf8 strings it prints the valid
// strings, otherwise it prints the byte sequence instead
#[stable(feature = "process_output_debug", since = "1.7.0")]
impl fmt::Debug for Output {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
let stdout_utf8 = str::from_utf8(&self.stdout);
let stdout_debug: &dyn fmt::Debug = match stdout_utf8 {
Ok(ref s) => s,
Err(_) => &self.stdout,
};
let stderr_utf8 = str::from_utf8(&self.stderr);
let stderr_debug: &dyn fmt::Debug = match stderr_utf8 {
Ok(ref s) => s,
Err(_) => &self.stderr,
};
fmt.debug_struct("Output")
.field("status", &self.status)
.field("stdout", stdout_debug)
.field("stderr", stderr_debug)
.finish()
}
}
/// Describes what to do with a standard I/O stream for a child process when
/// passed to the [`stdin`], [`stdout`], and [`stderr`] methods of [`Command`].
///
/// [`stdin`]: Command::stdin
/// [`stdout`]: Command::stdout
/// [`stderr`]: Command::stderr
#[stable(feature = "process", since = "1.0.0")]
pub struct Stdio(imp::Stdio);
impl Stdio {
/// A new pipe should be arranged to connect the parent and child processes.
///
/// # Examples
///
/// With stdout:
///
/// ```no_run
/// use std::process::{Command, Stdio};
///
/// let output = Command::new("echo")
/// .arg("Hello, world!")
/// .stdout(Stdio::piped())
/// .output()
/// .expect("Failed to execute command");
///
/// assert_eq!(String::from_utf8_lossy(&output.stdout), "Hello, world!\n");
/// // Nothing echoed to console
/// ```
///
/// With stdin:
///
/// ```no_run
/// use std::io::Write;
/// use std::process::{Command, Stdio};
///
/// let mut child = Command::new("rev")
/// .stdin(Stdio::piped())
/// .stdout(Stdio::piped())
/// .spawn()
/// .expect("Failed to spawn child process");
///
/// let mut stdin = child.stdin.take().expect("Failed to open stdin");
/// std::thread::spawn(move || {
/// stdin.write_all("Hello, world!".as_bytes()).expect("Failed to write to stdin");
/// });
///
/// let output = child.wait_with_output().expect("Failed to read stdout");
/// assert_eq!(String::from_utf8_lossy(&output.stdout), "!dlrow ,olleH");
/// ```
///
/// Writing more than a pipe buffer's worth of input to stdin without also reading
/// stdout and stderr at the same time may cause a deadlock.
/// This is an issue when running any program that doesn't guarantee that it reads
/// its entire stdin before writing more than a pipe buffer's worth of output.
/// The size of a pipe buffer varies on different targets.
///
#[must_use]
#[stable(feature = "process", since = "1.0.0")]
pub fn piped() -> Stdio {
Stdio(imp::Stdio::MakePipe)
}
/// The child inherits from the corresponding parent descriptor.
///
/// # Examples
///
/// With stdout:
///
/// ```no_run
/// use std::process::{Command, Stdio};
///
/// let output = Command::new("echo")
/// .arg("Hello, world!")
/// .stdout(Stdio::inherit())
/// .output()
/// .expect("Failed to execute command");
///
/// assert_eq!(String::from_utf8_lossy(&output.stdout), "");
/// // "Hello, world!" echoed to console
/// ```
///
/// With stdin:
///
/// ```no_run
/// use std::process::{Command, Stdio};
/// use std::io::{self, Write};
///
/// let output = Command::new("rev")
/// .stdin(Stdio::inherit())
/// .stdout(Stdio::piped())
/// .output()?;
///
/// print!("You piped in the reverse of: ");
/// io::stdout().write_all(&output.stdout)?;
/// # io::Result::Ok(())
/// ```
#[must_use]
#[stable(feature = "process", since = "1.0.0")]
pub fn inherit() -> Stdio {
Stdio(imp::Stdio::Inherit)
}
/// This stream will be ignored. This is the equivalent of attaching the
/// stream to `/dev/null`.
///
/// # Examples
///
/// With stdout:
///
/// ```no_run
/// use std::process::{Command, Stdio};
///
/// let output = Command::new("echo")
/// .arg("Hello, world!")
/// .stdout(Stdio::null())
/// .output()
/// .expect("Failed to execute command");
///
/// assert_eq!(String::from_utf8_lossy(&output.stdout), "");
/// // Nothing echoed to console
/// ```
///
/// With stdin:
///
/// ```no_run
/// use std::process::{Command, Stdio};
///
/// let output = Command::new("rev")
/// .stdin(Stdio::null())
/// .stdout(Stdio::piped())
/// .output()
/// .expect("Failed to execute command");
///
/// assert_eq!(String::from_utf8_lossy(&output.stdout), "");
/// // Ignores any piped-in input
/// ```
#[must_use]
#[stable(feature = "process", since = "1.0.0")]
pub fn null() -> Stdio {
Stdio(imp::Stdio::Null)
}
/// Returns `true` if this requires [`Command`] to create a new pipe.
///
/// # Example
///
/// ```
/// #![feature(stdio_makes_pipe)]
/// use std::process::Stdio;
///
/// let io = Stdio::piped();
/// assert_eq!(io.makes_pipe(), true);
/// ```
#[unstable(feature = "stdio_makes_pipe", issue = "98288")]
pub fn makes_pipe(&self) -> bool {
matches!(self.0, imp::Stdio::MakePipe)
}
}
impl FromInner<imp::Stdio> for Stdio {
fn from_inner(inner: imp::Stdio) -> Stdio {
Stdio(inner)
}
}
#[stable(feature = "std_debug", since = "1.16.0")]
impl fmt::Debug for Stdio {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("Stdio").finish_non_exhaustive()
}
}
#[stable(feature = "stdio_from", since = "1.20.0")]
impl From<ChildStdin> for Stdio {
/// Converts a [`ChildStdin`] into a [`Stdio`].
///
/// # Examples
///
/// `ChildStdin` will be converted to `Stdio` using `Stdio::from` under the hood.
///
/// ```rust,no_run
/// use std::process::{Command, Stdio};
///
/// let reverse = Command::new("rev")
/// .stdin(Stdio::piped())
/// .spawn()
/// .expect("failed reverse command");
///
/// let _echo = Command::new("echo")
/// .arg("Hello, world!")
/// .stdout(reverse.stdin.unwrap()) // Converted into a Stdio here
/// .output()
/// .expect("failed echo command");
///
/// // "!dlrow ,olleH" echoed to console
/// ```
fn from(child: ChildStdin) -> Stdio {
Stdio::from_inner(child.into_inner().into())
}
}
#[stable(feature = "stdio_from", since = "1.20.0")]
impl From<ChildStdout> for Stdio {
/// Converts a [`ChildStdout`] into a [`Stdio`].
///
/// # Examples
///
/// `ChildStdout` will be converted to `Stdio` using `Stdio::from` under the hood.
///
/// ```rust,no_run
/// use std::process::{Command, Stdio};
///
/// let hello = Command::new("echo")
/// .arg("Hello, world!")
/// .stdout(Stdio::piped())
/// .spawn()
/// .expect("failed echo command");
///
/// let reverse = Command::new("rev")
/// .stdin(hello.stdout.unwrap()) // Converted into a Stdio here
/// .output()
/// .expect("failed reverse command");
///
/// assert_eq!(reverse.stdout, b"!dlrow ,olleH\n");
/// ```
fn from(child: ChildStdout) -> Stdio {
Stdio::from_inner(child.into_inner().into())
}
}
#[stable(feature = "stdio_from", since = "1.20.0")]
impl From<ChildStderr> for Stdio {
/// Converts a [`ChildStderr`] into a [`Stdio`].
///
/// # Examples
///
/// ```rust,no_run
/// use std::process::{Command, Stdio};
///
/// let reverse = Command::new("rev")
/// .arg("non_existing_file.txt")
/// .stderr(Stdio::piped())
/// .spawn()
/// .expect("failed reverse command");
///
/// let cat = Command::new("cat")
/// .arg("-")
/// .stdin(reverse.stderr.unwrap()) // Converted into a Stdio here
/// .output()
/// .expect("failed echo command");
///
/// assert_eq!(
/// String::from_utf8_lossy(&cat.stdout),
/// "rev: cannot open non_existing_file.txt: No such file or directory\n"
/// );
/// ```
fn from(child: ChildStderr) -> Stdio {
Stdio::from_inner(child.into_inner().into())
}
}
#[stable(feature = "stdio_from", since = "1.20.0")]
impl From<fs::File> for Stdio {
/// Converts a [`File`](fs::File) into a [`Stdio`].
///
/// # Examples
///
/// `File` will be converted to `Stdio` using `Stdio::from` under the hood.
///
/// ```rust,no_run
/// use std::fs::File;
/// use std::process::Command;
///
/// // With the `foo.txt` file containing "Hello, world!"
/// let file = File::open("foo.txt")?;
///
/// let reverse = Command::new("rev")
/// .stdin(file) // Implicit File conversion into a Stdio
/// .output()?;
///
/// assert_eq!(reverse.stdout, b"!dlrow ,olleH");
/// # std::io::Result::Ok(())
/// ```
fn from(file: fs::File) -> Stdio {
Stdio::from_inner(file.into_inner().into())
}
}
#[stable(feature = "stdio_from_stdio", since = "1.74.0")]
impl From<io::Stdout> for Stdio {
/// Redirect command stdout/stderr to our stdout
///
/// # Examples
///
/// ```rust
/// #![feature(exit_status_error)]
/// use std::io;
/// use std::process::Command;
///
/// # fn test() -> Result<(), Box<dyn std::error::Error>> {
/// let output = Command::new("whoami")
// "whoami" is a command which exists on both Unix and Windows,
// and which succeeds, producing some stdout output but no stderr.
/// .stdout(io::stdout())
/// .output()?;
/// output.status.exit_ok()?;
/// assert!(output.stdout.is_empty());
/// # Ok(())
/// # }
/// #
/// # if cfg!(all(unix, not(target_os = "android"), not(all(target_vendor = "apple", not(target_os = "macos"))))) {
/// # test().unwrap();
/// # }
/// ```
fn from(inherit: io::Stdout) -> Stdio {
Stdio::from_inner(inherit.into())
}
}
#[stable(feature = "stdio_from_stdio", since = "1.74.0")]
impl From<io::Stderr> for Stdio {
/// Redirect command stdout/stderr to our stderr
///
/// # Examples
///
/// ```rust
/// #![feature(exit_status_error)]
/// use std::io;
/// use std::process::Command;
///
/// # fn test() -> Result<(), Box<dyn std::error::Error>> {
/// let output = Command::new("whoami")
/// .stdout(io::stderr())
/// .output()?;
/// output.status.exit_ok()?;
/// assert!(output.stdout.is_empty());
/// # Ok(())
/// # }
/// #
/// # if cfg!(all(unix, not(target_os = "android"), not(all(target_vendor = "apple", not(target_os = "macos"))))) {
/// # test().unwrap();
/// # }
/// ```
fn from(inherit: io::Stderr) -> Stdio {
Stdio::from_inner(inherit.into())
}
}
#[stable(feature = "anonymous_pipe", since = "1.87.0")]
impl From<io::PipeWriter> for Stdio {
fn from(pipe: io::PipeWriter) -> Self {
Stdio::from_inner(pipe.into_inner().into())
}
}
#[stable(feature = "anonymous_pipe", since = "1.87.0")]
impl From<io::PipeReader> for Stdio {
fn from(pipe: io::PipeReader) -> Self {
Stdio::from_inner(pipe.into_inner().into())
}
}
/// Describes the result of a process after it has terminated.
///
/// This `struct` is used to represent the exit status or other termination of a child process.
/// Child processes are created via the [`Command`] struct and their exit
/// status is exposed through the [`status`] method, or the [`wait`] method
/// of a [`Child`] process.
///
/// An `ExitStatus` represents every possible disposition of a process. On Unix this
/// is the **wait status**. It is *not* simply an *exit status* (a value passed to `exit`).
///
/// For proper error reporting of failed processes, print the value of `ExitStatus` or
/// `ExitStatusError` using their implementations of [`Display`](crate::fmt::Display).
///
/// # Differences from `ExitCode`
///
/// [`ExitCode`] is intended for terminating the currently running process, via
/// the `Termination` trait, in contrast to `ExitStatus`, which represents the
/// termination of a child process. These APIs are separate due to platform
/// compatibility differences and their expected usage; it is not generally
/// possible to exactly reproduce an `ExitStatus` from a child for the current
/// process after the fact.
///
/// [`status`]: Command::status
/// [`wait`]: Child::wait
//
// We speak slightly loosely (here and in various other places in the stdlib docs) about `exit`
// vs `_exit`. Naming of Unix system calls is not standardised across Unices, so terminology is a
// matter of convention and tradition. For clarity we usually speak of `exit`, even when we might
// mean an underlying system call such as `_exit`.
#[derive(PartialEq, Eq, Clone, Copy, Debug)]
#[stable(feature = "process", since = "1.0.0")]
pub struct ExitStatus(imp::ExitStatus);
/// The default value is one which indicates successful completion.
#[stable(feature = "process_exitstatus_default", since = "1.73.0")]
impl Default for ExitStatus {
fn default() -> Self {
// Ideally this would be done by ExitCode::default().into() but that is complicated.
ExitStatus::from_inner(imp::ExitStatus::default())
}
}
/// Allows extension traits within `std`.
#[unstable(feature = "sealed", issue = "none")]
impl crate::sealed::Sealed for ExitStatus {}
impl ExitStatus {
/// Was termination successful? Returns a `Result`.
///
/// # Examples
///
/// ```
/// #![feature(exit_status_error)]
/// # if cfg!(all(unix, not(all(target_vendor = "apple", not(target_os = "macos"))))) {
/// use std::process::Command;
///
/// let status = Command::new("ls")
/// .arg("/dev/nonexistent")
/// .status()
/// .expect("ls could not be executed");
///
/// println!("ls: {status}");
/// status.exit_ok().expect_err("/dev/nonexistent could be listed!");
/// # } // cfg!(unix)
/// ```
#[unstable(feature = "exit_status_error", issue = "84908")]
pub fn exit_ok(&self) -> Result<(), ExitStatusError> {
self.0.exit_ok().map_err(ExitStatusError)
}
/// Was termination successful? Signal termination is not considered a
/// success, and success is defined as a zero exit status.
///
/// # Examples
///
/// ```rust,no_run
/// use std::process::Command;
///
/// let status = Command::new("mkdir")
/// .arg("projects")
/// .status()
/// .expect("failed to execute mkdir");
///
/// if status.success() {
/// println!("'projects/' directory created");
/// } else {
/// println!("failed to create 'projects/' directory: {status}");
/// }
/// ```
#[must_use]
#[stable(feature = "process", since = "1.0.0")]
pub fn success(&self) -> bool {
self.0.exit_ok().is_ok()
}
/// Returns the exit code of the process, if any.
///
/// In Unix terms the return value is the **exit status**: the value passed to `exit`, if the
/// process finished by calling `exit`. Note that on Unix the exit status is truncated to 8
/// bits, and that values that didn't come from a program's call to `exit` may be invented by the
/// runtime system (often, for example, 255, 254, 127 or 126).
///
/// On Unix, this will return `None` if the process was terminated by a signal.
/// [`ExitStatusExt`](crate::os::unix::process::ExitStatusExt) is an
/// extension trait for extracting any such signal, and other details, from the `ExitStatus`.
///
/// # Examples
///
/// ```no_run
/// use std::process::Command;
///
/// let status = Command::new("mkdir")
/// .arg("projects")
/// .status()
/// .expect("failed to execute mkdir");
///
/// match status.code() {
/// Some(code) => println!("Exited with status code: {code}"),
/// None => println!("Process terminated by signal")
/// }
/// ```
#[must_use]
#[stable(feature = "process", since = "1.0.0")]
pub fn code(&self) -> Option<i32> {
self.0.code()
}
}
impl AsInner<imp::ExitStatus> for ExitStatus {
#[inline]
fn as_inner(&self) -> &imp::ExitStatus {
&self.0
}
}
impl FromInner<imp::ExitStatus> for ExitStatus {
fn from_inner(s: imp::ExitStatus) -> ExitStatus {
ExitStatus(s)
}
}
#[stable(feature = "process", since = "1.0.0")]
impl fmt::Display for ExitStatus {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.0.fmt(f)
}
}
/// Allows extension traits within `std`.
#[unstable(feature = "sealed", issue = "none")]
impl crate::sealed::Sealed for ExitStatusError {}
/// Describes the result of a process after it has failed
///
/// Produced by the [`.exit_ok`](ExitStatus::exit_ok) method on [`ExitStatus`].
///
/// # Examples
///
/// ```
/// #![feature(exit_status_error)]
/// # if cfg!(all(unix, not(target_os = "android"), not(all(target_vendor = "apple", not(target_os = "macos"))))) {
/// use std::process::{Command, ExitStatusError};
///
/// fn run(cmd: &str) -> Result<(), ExitStatusError> {
/// Command::new(cmd).status().unwrap().exit_ok()?;
/// Ok(())
/// }
///
/// run("true").unwrap();
/// run("false").unwrap_err();
/// # } // cfg!(unix)
/// ```
#[derive(PartialEq, Eq, Clone, Copy, Debug)]
#[unstable(feature = "exit_status_error", issue = "84908")]
// The definition of imp::ExitStatusError should ideally be such that
// Result<(), imp::ExitStatusError> has an identical representation to imp::ExitStatus.
pub struct ExitStatusError(imp::ExitStatusError);
#[unstable(feature = "exit_status_error", issue = "84908")]
#[doc(test(attr(allow(unused_features))))]
impl ExitStatusError {
/// Reports the exit code, if applicable, from an `ExitStatusError`.
///
/// In Unix terms the return value is the **exit status**: the value passed to `exit`, if the
/// process finished by calling `exit`. Note that on Unix the exit status is truncated to 8
/// bits, and that values that didn't come from a program's call to `exit` may be invented by the
/// runtime system (often, for example, 255, 254, 127 or 126).
///
/// On Unix, this will return `None` if the process was terminated by a signal. If you want to
/// handle such situations specially, consider using methods from
/// [`ExitStatusExt`](crate::os::unix::process::ExitStatusExt).
///
/// If the process finished by calling `exit` with a nonzero value, this will return
/// that exit status.
///
/// If the error was something else, it will return `None`.
///
/// If the process exited successfully (ie, by calling `exit(0)`), there is no
/// `ExitStatusError`. So the return value from `ExitStatusError::code()` is always nonzero.
///
/// # Examples
///
/// ```
/// #![feature(exit_status_error)]
/// # #[cfg(all(unix, not(target_os = "android"), not(all(target_vendor = "apple", not(target_os = "macos")))))] {
/// use std::process::Command;
///
/// let bad = Command::new("false").status().unwrap().exit_ok().unwrap_err();
/// assert_eq!(bad.code(), Some(1));
/// # } // #[cfg(unix)]
/// ```
#[must_use]
pub fn code(&self) -> Option<i32> {
self.code_nonzero().map(Into::into)
}
/// Reports the exit code, if applicable, from an `ExitStatusError`, as a [`NonZero`].
///
/// This is exactly like [`code()`](Self::code), except that it returns a <code>[NonZero]<[i32]></code>.
///
/// Plain `code`, returning a plain integer, is provided because it is often more convenient.
/// The returned value from `code()` is indeed also nonzero; use `code_nonzero()` when you want
/// a type-level guarantee of nonzeroness.
///
/// # Examples
///
/// ```
/// #![feature(exit_status_error)]
///
/// # if cfg!(all(unix, not(target_os = "android"), not(all(target_vendor = "apple", not(target_os = "macos"))))) {
/// use std::num::NonZero;
/// use std::process::Command;
///
/// let bad = Command::new("false").status().unwrap().exit_ok().unwrap_err();
/// assert_eq!(bad.code_nonzero().unwrap(), NonZero::new(1).unwrap());
/// # } // cfg!(unix)
/// ```
#[must_use]
pub fn code_nonzero(&self) -> Option<NonZero<i32>> {
self.0.code()
}
/// Converts an `ExitStatusError` (back) to an `ExitStatus`.
#[must_use]
pub fn into_status(&self) -> ExitStatus {
ExitStatus(self.0.into())
}
}
#[unstable(feature = "exit_status_error", issue = "84908")]
impl From<ExitStatusError> for ExitStatus {
fn from(error: ExitStatusError) -> Self {
Self(error.0.into())
}
}
#[unstable(feature = "exit_status_error", issue = "84908")]
impl fmt::Display for ExitStatusError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "process exited unsuccessfully: {}", self.into_status())
}
}
#[unstable(feature = "exit_status_error", issue = "84908")]
impl crate::error::Error for ExitStatusError {}
/// This type represents the status code the current process can return
/// to its parent under normal termination.
///
/// `ExitCode` is intended to be consumed only by the standard library (via
/// [`Termination::report()`]). For forwards compatibility with potentially
/// unusual targets, this type currently does not provide `Eq`, `Hash`, or
/// access to the raw value. This type does provide `PartialEq` for
/// comparison, but note that there may potentially be multiple failure
/// codes, some of which will _not_ compare equal to `ExitCode::FAILURE`.
/// The standard library provides the canonical `SUCCESS` and `FAILURE`
/// exit codes as well as `From<u8> for ExitCode` for constructing other
/// arbitrary exit codes.
///
/// # Portability
///
/// Numeric values used in this type don't have portable meanings, and
/// different platforms may mask different amounts of them.
///
/// For the platform's canonical successful and unsuccessful codes, see
/// the [`SUCCESS`] and [`FAILURE`] associated items.
///
/// [`SUCCESS`]: ExitCode::SUCCESS
/// [`FAILURE`]: ExitCode::FAILURE
///
/// # Differences from `ExitStatus`
///
/// `ExitCode` is intended for terminating the currently running process, via
/// the `Termination` trait, in contrast to [`ExitStatus`], which represents the
/// termination of a child process. These APIs are separate due to platform
/// compatibility differences and their expected usage; it is not generally
/// possible to exactly reproduce an `ExitStatus` from a child for the current
/// process after the fact.
///
/// # Examples
///
/// `ExitCode` can be returned from the `main` function of a crate, as it implements
/// [`Termination`]:
///
/// ```
/// use std::process::ExitCode;
/// # fn check_foo() -> bool { true }
///
/// fn main() -> ExitCode {
/// if !check_foo() {
/// return ExitCode::from(42);
/// }
///
/// ExitCode::SUCCESS
/// }
/// ```
#[derive(Clone, Copy, Debug, PartialEq)]
#[stable(feature = "process_exitcode", since = "1.61.0")]
pub struct ExitCode(imp::ExitCode);
/// Allows extension traits within `std`.
#[unstable(feature = "sealed", issue = "none")]
impl crate::sealed::Sealed for ExitCode {}
#[stable(feature = "process_exitcode", since = "1.61.0")]
impl ExitCode {
/// The canonical `ExitCode` for successful termination on this platform.
///
/// Note that a `()`-returning `main` implicitly results in a successful
/// termination, so there's no need to return this from `main` unless
/// you're also returning other possible codes.
#[stable(feature = "process_exitcode", since = "1.61.0")]
pub const SUCCESS: ExitCode = ExitCode(imp::ExitCode::SUCCESS);
/// The canonical `ExitCode` for unsuccessful termination on this platform.
///
/// If you're only returning this and `SUCCESS` from `main`, consider
/// instead returning `Err(_)` and `Ok(())` respectively, which will
/// return the same codes (but will also `eprintln!` the error).
#[stable(feature = "process_exitcode", since = "1.61.0")]
pub const FAILURE: ExitCode = ExitCode(imp::ExitCode::FAILURE);
/// Exit the current process with the given `ExitCode`.
///
/// Note that this has the same caveats as [`process::exit()`][exit], namely that this function
/// terminates the process immediately, so no destructors on the current stack or any other
/// thread's stack will be run. Also see those docs for some important notes on interop with C
/// code. If a clean shutdown is needed, it is recommended to simply return this ExitCode from
/// the `main` function, as demonstrated in the [type documentation](#examples).
///
/// # Differences from `process::exit()`
///
/// `process::exit()` accepts any `i32` value as the exit code for the process; however, there
/// are platforms that only use a subset of that value (see [`process::exit` platform-specific
/// behavior][exit#platform-specific-behavior]). `ExitCode` exists because of this; only
/// `ExitCode`s that are supported by a majority of our platforms can be created, so those
/// problems don't exist (as much) with this method.
///
/// # Examples
///
/// ```
/// #![feature(exitcode_exit_method)]
/// # use std::process::ExitCode;
/// # use std::fmt;
/// # enum UhOhError { GenericProblem, Specific, WithCode { exit_code: ExitCode, _x: () } }
/// # impl fmt::Display for UhOhError {
/// # fn fmt(&self, _: &mut fmt::Formatter<'_>) -> fmt::Result { unimplemented!() }
/// # }
/// // there's no way to gracefully recover from an UhOhError, so we just
/// // print a message and exit
/// fn handle_unrecoverable_error(err: UhOhError) -> ! {
/// eprintln!("UH OH! {err}");
/// let code = match err {
/// UhOhError::GenericProblem => ExitCode::FAILURE,
/// UhOhError::Specific => ExitCode::from(3),
/// UhOhError::WithCode { exit_code, .. } => exit_code,
/// };
/// code.exit_process()
/// }
/// ```
#[unstable(feature = "exitcode_exit_method", issue = "97100")]
pub fn exit_process(self) -> ! {
exit(self.to_i32())
}
}
impl ExitCode {
// This is private/perma-unstable because ExitCode is opaque; we don't know that i32 will serve
// all usecases, for example windows seems to use u32, unix uses the 8-15th bits of an i32, we
// likely want to isolate users anything that could restrict the platform specific
// representation of an ExitCode
//
// More info: https://internals.rust-lang.org/t/mini-pre-rfc-redesigning-process-exitstatus/5426
/// Converts an `ExitCode` into an i32
#[unstable(
feature = "process_exitcode_internals",
reason = "exposed only for libstd",
issue = "none"
)]
#[inline]
#[doc(hidden)]
pub fn to_i32(self) -> i32 {
self.0.as_i32()
}
}
/// The default value is [`ExitCode::SUCCESS`]
#[stable(feature = "process_exitcode_default", since = "1.75.0")]
impl Default for ExitCode {
fn default() -> Self {
ExitCode::SUCCESS
}
}
#[stable(feature = "process_exitcode", since = "1.61.0")]
impl From<u8> for ExitCode {
/// Constructs an `ExitCode` from an arbitrary u8 value.
fn from(code: u8) -> Self {
ExitCode(imp::ExitCode::from(code))
}
}
impl AsInner<imp::ExitCode> for ExitCode {
#[inline]
fn as_inner(&self) -> &imp::ExitCode {
&self.0
}
}
impl FromInner<imp::ExitCode> for ExitCode {
fn from_inner(s: imp::ExitCode) -> ExitCode {
ExitCode(s)
}
}
impl Child {
/// Forces the child process to exit. If the child has already exited, `Ok(())`
/// is returned.
///
/// The mapping to [`ErrorKind`]s is not part of the compatibility contract of the function.
///
/// This is equivalent to sending a SIGKILL on Unix platforms.
///
/// # Examples
///
/// ```no_run
/// use std::process::Command;
///
/// let mut command = Command::new("yes");
/// if let Ok(mut child) = command.spawn() {
/// child.kill().expect("command couldn't be killed");
/// } else {
/// println!("yes command didn't start");
/// }
/// ```
///
/// [`ErrorKind`]: io::ErrorKind
/// [`InvalidInput`]: io::ErrorKind::InvalidInput
#[stable(feature = "process", since = "1.0.0")]
#[cfg_attr(not(test), rustc_diagnostic_item = "child_kill")]
pub fn kill(&mut self) -> io::Result<()> {
self.handle.kill()
}
/// Returns the OS-assigned process identifier associated with this child.
///
/// # Examples
///
/// ```no_run
/// use std::process::Command;
///
/// let mut command = Command::new("ls");
/// if let Ok(child) = command.spawn() {
/// println!("Child's ID is {}", child.id());
/// } else {
/// println!("ls command didn't start");
/// }
/// ```
#[must_use]
#[stable(feature = "process_id", since = "1.3.0")]
#[cfg_attr(not(test), rustc_diagnostic_item = "child_id")]
pub fn id(&self) -> u32 {
self.handle.id()
}
/// Waits for the child to exit completely, returning the status that it
/// exited with. This function will continue to have the same return value
/// after it has been called at least once.
///
/// The stdin handle to the child process, if any, will be closed
/// before waiting. This helps avoid deadlock: it ensures that the
/// child does not block waiting for input from the parent, while
/// the parent waits for the child to exit.
///
/// # Examples
///
/// ```no_run
/// use std::process::Command;
///
/// let mut command = Command::new("ls");
/// if let Ok(mut child) = command.spawn() {
/// child.wait().expect("command wasn't running");
/// println!("Child has finished its execution!");
/// } else {
/// println!("ls command didn't start");
/// }
/// ```
#[stable(feature = "process", since = "1.0.0")]
pub fn wait(&mut self) -> io::Result<ExitStatus> {
drop(self.stdin.take());
self.handle.wait().map(ExitStatus)
}
/// Attempts to collect the exit status of the child if it has already
/// exited.
///
/// This function will not block the calling thread and will only
/// check to see if the child process has exited or not. If the child has
/// exited then on Unix the process ID is reaped. This function is
/// guaranteed to repeatedly return a successful exit status so long as the
/// child has already exited.
///
/// If the child has exited, then `Ok(Some(status))` is returned. If the
/// exit status is not available at this time then `Ok(None)` is returned.
/// If an error occurs, then that error is returned.
///
/// Note that unlike `wait`, this function will not attempt to drop stdin.
///
/// # Examples
///
/// ```no_run
/// use std::process::Command;
///
/// let mut child = Command::new("ls").spawn()?;
///
/// match child.try_wait() {
/// Ok(Some(status)) => println!("exited with: {status}"),
/// Ok(None) => {
/// println!("status not ready yet, let's really wait");
/// let res = child.wait();
/// println!("result: {res:?}");
/// }
/// Err(e) => println!("error attempting to wait: {e}"),
/// }
/// # std::io::Result::Ok(())
/// ```
#[stable(feature = "process_try_wait", since = "1.18.0")]
pub fn try_wait(&mut self) -> io::Result<Option<ExitStatus>> {
Ok(self.handle.try_wait()?.map(ExitStatus))
}
/// Simultaneously waits for the child to exit and collect all remaining
/// output on the stdout/stderr handles, returning an `Output`
/// instance.
///
/// The stdin handle to the child process, if any, will be closed
/// before waiting. This helps avoid deadlock: it ensures that the
/// child does not block waiting for input from the parent, while
/// the parent waits for the child to exit.
///
/// By default, stdin, stdout and stderr are inherited from the parent.
/// In order to capture the output into this `Result<Output>` it is
/// necessary to create new pipes between parent and child. Use
/// `stdout(Stdio::piped())` or `stderr(Stdio::piped())`, respectively.
///
/// # Examples
///
/// ```should_panic
/// use std::process::{Command, Stdio};
///
/// let child = Command::new("/bin/cat")
/// .arg("file.txt")
/// .stdout(Stdio::piped())
/// .spawn()
/// .expect("failed to execute child");
///
/// let output = child
/// .wait_with_output()
/// .expect("failed to wait on child");
///
/// assert!(output.status.success());
/// ```
///
#[stable(feature = "process", since = "1.0.0")]
pub fn wait_with_output(mut self) -> io::Result<Output> {
drop(self.stdin.take());
let (mut stdout, mut stderr) = (Vec::new(), Vec::new());
match (self.stdout.take(), self.stderr.take()) {
(None, None) => {}
(Some(mut out), None) => {
let res = out.read_to_end(&mut stdout);
res.unwrap();
}
(None, Some(mut err)) => {
let res = err.read_to_end(&mut stderr);
res.unwrap();
}
(Some(out), Some(err)) => {
let res = imp::read_output(out.inner, &mut stdout, err.inner, &mut stderr);
res.unwrap();
}
}
let status = self.wait()?;
Ok(Output { status, stdout, stderr })
}
}
/// Terminates the current process with the specified exit code.
///
/// This function will never return and will immediately terminate the current
/// process. The exit code is passed through to the underlying OS and will be
/// available for consumption by another process.
///
/// Note that because this function never returns, and that it terminates the
/// process, no destructors on the current stack or any other thread's stack
/// will be run. If a clean shutdown is needed it is recommended to only call
/// this function at a known point where there are no more destructors left
/// to run; or, preferably, simply return a type implementing [`Termination`]
/// (such as [`ExitCode`] or `Result`) from the `main` function and avoid this
/// function altogether:
///
/// ```
/// # use std::io::Error as MyError;
/// fn main() -> Result<(), MyError> {
/// // ...
/// Ok(())
/// }
/// ```
///
/// In its current implementation, this function will execute exit handlers registered with `atexit`
/// as well as other platform-specific exit handlers (e.g. `fini` sections of ELF shared objects).
/// This means that Rust requires that all exit handlers are safe to execute at any time. In
/// particular, if an exit handler cleans up some state that might be concurrently accessed by other
/// threads, it is required that the exit handler performs suitable synchronization with those
/// threads. (The alternative to this requirement would be to not run exit handlers at all, which is
/// considered undesirable. Note that returning from `main` also calls `exit`, so making `exit` an
/// unsafe operation is not an option.)
///
/// ## Platform-specific behavior
///
/// **Unix**: On Unix-like platforms, it is unlikely that all 32 bits of `exit`
/// will be visible to a parent process inspecting the exit code. On most
/// Unix-like platforms, only the eight least-significant bits are considered.
///
/// For example, the exit code for this example will be `0` on Linux, but `256`
/// on Windows:
///
/// ```no_run
/// use std::process;
///
/// process::exit(0x0100);
/// ```
///
/// ### Safe interop with C code
///
/// On Unix, this function is currently implemented using the `exit` C function [`exit`][C-exit]. As
/// of C23, the C standard does not permit multiple threads to call `exit` concurrently. Rust
/// mitigates this with a lock, but if C code calls `exit`, that can still cause undefined behavior.
/// Note that returning from `main` is equivalent to calling `exit`.
///
/// Therefore, it is undefined behavior to have two concurrent threads perform the following
/// without synchronization:
/// - One thread calls Rust's `exit` function or returns from Rust's `main` function
/// - Another thread calls the C function `exit` or `quick_exit`, or returns from C's `main` function
///
/// Note that if a binary contains multiple copies of the Rust runtime (e.g., when combining
/// multiple `cdylib` or `staticlib`), they each have their own separate lock, so from the
/// perspective of code running in one of the Rust runtimes, the "outside" Rust code is basically C
/// code, and concurrent `exit` again causes undefined behavior.
///
/// Individual C implementations might provide more guarantees than the standard and permit concurrent
/// calls to `exit`; consult the documentation of your C implementation for details.
///
/// For some of the on-going discussion to make `exit` thread-safe in C, see:
/// - [Rust issue #126600](https://github.com/rust-lang/rust/issues/126600)
/// - [Austin Group Bugzilla (for POSIX)](https://austingroupbugs.net/view.php?id=1845)
/// - [GNU C library Bugzilla](https://sourceware.org/bugzilla/show_bug.cgi?id=31997)
///
/// [C-exit]: https://en.cppreference.com/w/c/program/exit
#[stable(feature = "rust1", since = "1.0.0")]
#[cfg_attr(not(test), rustc_diagnostic_item = "process_exit")]
pub fn exit(code: i32) -> ! {
crate::rt::cleanup();
crate::sys::exit::exit(code)
}
/// Terminates the process in an abnormal fashion.
///
/// The function will never return and will immediately terminate the current
/// process in a platform specific "abnormal" manner. As a consequence,
/// no destructors on the current stack or any other thread's stack
/// will be run, Rust IO buffers (eg, from `BufWriter`) will not be flushed,
/// and C stdio buffers will (on most platforms) not be flushed.
///
/// This is in contrast to the default behavior of [`panic!`] which unwinds
/// the current thread's stack and calls all destructors.
/// When `panic="abort"` is set, either as an argument to `rustc` or in a
/// crate's Cargo.toml, [`panic!`] and `abort` are similar. However,
/// [`panic!`] will still call the [panic hook] while `abort` will not.
///
/// If a clean shutdown is needed it is recommended to only call
/// this function at a known point where there are no more destructors left
/// to run.
///
/// The process's termination will be similar to that from the C `abort()`
/// function. On Unix, the process will terminate with signal `SIGABRT`, which
/// typically means that the shell prints "Aborted".
///
/// # Examples
///
/// ```no_run
/// use std::process;
///
/// fn main() {
/// println!("aborting");
///
/// process::abort();
///
/// // execution never gets here
/// }
/// ```
///
/// The `abort` function terminates the process, so the destructor will not
/// get run on the example below:
///
/// ```no_run
/// use std::process;
///
/// struct HasDrop;
///
/// impl Drop for HasDrop {
/// fn drop(&mut self) {
/// println!("This will never be printed!");
/// }
/// }
///
/// fn main() {
/// let _x = HasDrop;
/// process::abort();
/// // the destructor implemented for HasDrop will never get run
/// }
/// ```
///
/// [panic hook]: crate::panic::set_hook
#[stable(feature = "process_abort", since = "1.17.0")]
#[cold]
#[cfg_attr(not(test), rustc_diagnostic_item = "process_abort")]
#[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
pub fn abort() -> ! {
crate::sys::abort_internal();
}
#[doc(inline)]
#[unstable(feature = "abort_immediate", issue = "154601")]
pub use core::process::abort_immediate;
/// Returns the OS-assigned process identifier associated with this process.
///
/// # Examples
///
/// ```no_run
/// use std::process;
///
/// println!("My pid is {}", process::id());
/// ```
#[must_use]
#[stable(feature = "getpid", since = "1.26.0")]
pub fn id() -> u32 {
imp::getpid()
}
/// A trait for implementing arbitrary return types in the `main` function.
///
/// The C-main function only supports returning integers.
/// So, every type implementing the `Termination` trait has to be converted
/// to an integer.
///
/// The default implementations are returning `libc::EXIT_SUCCESS` to indicate
/// a successful execution. In case of a failure, `libc::EXIT_FAILURE` is returned.
///
/// Because different runtimes have different specifications on the return value
/// of the `main` function, this trait is likely to be available only on
/// standard library's runtime for convenience. Other runtimes are not required
/// to provide similar functionality.
#[cfg_attr(not(any(test, doctest)), lang = "termination")]
#[stable(feature = "termination_trait_lib", since = "1.61.0")]
#[rustc_on_unimplemented(on(
cause = "MainFunctionType",
message = "`main` has invalid return type `{Self}`",
label = "`main` can only return types that implement `{This}`"
))]
pub trait Termination {
/// Is called to get the representation of the value as status code.
/// This status code is returned to the operating system.
#[stable(feature = "termination_trait_lib", since = "1.61.0")]
fn report(self) -> ExitCode;
}
#[stable(feature = "termination_trait_lib", since = "1.61.0")]
impl Termination for () {
#[inline]
fn report(self) -> ExitCode {
ExitCode::SUCCESS
}
}
#[stable(feature = "termination_trait_lib", since = "1.61.0")]
impl Termination for ! {
fn report(self) -> ExitCode {
self
}
}
#[stable(feature = "termination_trait_lib", since = "1.61.0")]
impl Termination for Infallible {
fn report(self) -> ExitCode {
match self {}
}
}
#[stable(feature = "termination_trait_lib", since = "1.61.0")]
impl Termination for ExitCode {
#[inline]
fn report(self) -> ExitCode {
self
}
}
#[stable(feature = "termination_trait_lib", since = "1.61.0")]
impl<T: Termination, E: fmt::Debug> Termination for Result<T, E> {
fn report(self) -> ExitCode {
match self {
Ok(val) => val.report(),
Err(err) => {
io::attempt_print_to_stderr(format_args_nl!("Error: {err:?}"));
ExitCode::FAILURE
}
}
}
}