rust/library/std/src/sys/unix/ext/process.rs
2020-08-19 05:43:55 +05:30

229 lines
8.3 KiB
Rust
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

//! Unix-specific extensions to primitives in the `std::process` module.
#![stable(feature = "rust1", since = "1.0.0")]
use crate::ffi::OsStr;
use crate::io;
use crate::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd, RawFd};
use crate::process;
use crate::sys;
use crate::sys_common::{AsInner, AsInnerMut, FromInner, IntoInner};
/// Unix-specific extensions to the [`process::Command`] builder.
#[stable(feature = "rust1", since = "1.0.0")]
pub trait CommandExt {
/// Sets the child process's user ID. This translates to a
/// `setuid` call in the child process. Failure in the `setuid`
/// call will cause the spawn to fail.
#[stable(feature = "rust1", since = "1.0.0")]
fn uid(&mut self, id: u32) -> &mut process::Command;
/// Similar to `uid`, but sets the group ID of the child process. This has
/// the same semantics as the `uid` field.
#[stable(feature = "rust1", since = "1.0.0")]
fn gid(&mut self, id: u32) -> &mut process::Command;
/// Schedules a closure to be run just before the `exec` function is
/// invoked.
///
/// The closure is allowed to return an I/O error whose OS error code will
/// be communicated back to the parent and returned as an error from when
/// the spawn was requested.
///
/// Multiple closures can be registered and they will be called in order of
/// their registration. If a closure returns `Err` then no further closures
/// will be called and the spawn operation will immediately return with a
/// failure.
///
/// # Notes and Safety
///
/// This closure will be run in the context of the child process after a
/// `fork`. This primarily means that any modifications made to memory on
/// behalf of this closure will **not** be visible to the parent process.
/// This is often a very constrained environment where normal operations
/// like `malloc` or acquiring a mutex are not guaranteed to work (due to
/// other threads perhaps still running when the `fork` was run).
///
/// This also means that all resources such as file descriptors and
/// memory-mapped regions got duplicated. It is your responsibility to make
/// sure that the closure does not violate library invariants by making
/// invalid use of these duplicates.
///
/// When this closure is run, aspects such as the stdio file descriptors and
/// working directory have successfully been changed, so output to these
/// locations may not appear where intended.
#[stable(feature = "process_pre_exec", since = "1.34.0")]
unsafe fn pre_exec<F>(&mut self, f: F) -> &mut process::Command
where
F: FnMut() -> io::Result<()> + Send + Sync + 'static;
/// Schedules a closure to be run just before the `exec` function is
/// invoked.
///
/// This method is stable and usable, but it should be unsafe. To fix
/// that, it got deprecated in favor of the unsafe [`pre_exec`].
///
/// [`pre_exec`]: CommandExt::pre_exec
#[stable(feature = "process_exec", since = "1.15.0")]
#[rustc_deprecated(since = "1.37.0", reason = "should be unsafe, use `pre_exec` instead")]
fn before_exec<F>(&mut self, f: F) -> &mut process::Command
where
F: FnMut() -> io::Result<()> + Send + Sync + 'static,
{
unsafe { self.pre_exec(f) }
}
/// Performs all the required setup by this `Command`, followed by calling
/// the `execvp` syscall.
///
/// On success this function will not return, and otherwise it will return
/// an error indicating why the exec (or another part of the setup of the
/// `Command`) failed.
///
/// `exec` not returning has the same implications as calling
/// [`process::exit`] no destructors on the current stack or any other
/// threads stack will be run. Therefore, it is recommended to only call
/// `exec` at a point where it is fine to not run any destructors. Note,
/// that the `execvp` syscall independently guarantees that all memory is
/// freed and all file descriptors with the `CLOEXEC` option (set by default
/// on all file descriptors opened by the standard library) are closed.
///
/// This function, unlike `spawn`, will **not** `fork` the process to create
/// a new child. Like spawn, however, the default behavior for the stdio
/// descriptors will be to inherited from the current process.
///
/// # Notes
///
/// The process may be in a "broken state" if this function returns in
/// error. For example the working directory, environment variables, signal
/// handling settings, various user/group information, or aspects of stdio
/// file descriptors may have changed. If a "transactional spawn" is
/// required to gracefully handle errors it is recommended to use the
/// cross-platform `spawn` instead.
#[stable(feature = "process_exec2", since = "1.9.0")]
fn exec(&mut self) -> io::Error;
/// Set executable argument
///
/// Set the first process argument, `argv[0]`, to something other than the
/// default executable path.
#[stable(feature = "process_set_argv0", since = "1.45.0")]
fn arg0<S>(&mut self, arg: S) -> &mut process::Command
where
S: AsRef<OsStr>;
}
#[stable(feature = "rust1", since = "1.0.0")]
impl CommandExt for process::Command {
fn uid(&mut self, id: u32) -> &mut process::Command {
self.as_inner_mut().uid(id);
self
}
fn gid(&mut self, id: u32) -> &mut process::Command {
self.as_inner_mut().gid(id);
self
}
unsafe fn pre_exec<F>(&mut self, f: F) -> &mut process::Command
where
F: FnMut() -> io::Result<()> + Send + Sync + 'static,
{
self.as_inner_mut().pre_exec(Box::new(f));
self
}
fn exec(&mut self) -> io::Error {
self.as_inner_mut().exec(sys::process::Stdio::Inherit)
}
fn arg0<S>(&mut self, arg: S) -> &mut process::Command
where
S: AsRef<OsStr>,
{
self.as_inner_mut().set_arg_0(arg.as_ref());
self
}
}
/// Unix-specific extensions to [`process::ExitStatus`].
#[stable(feature = "rust1", since = "1.0.0")]
pub trait ExitStatusExt {
/// Creates a new `ExitStatus` from the raw underlying `i32` return value of
/// a process.
#[stable(feature = "exit_status_from", since = "1.12.0")]
fn from_raw(raw: i32) -> Self;
/// If the process was terminated by a signal, returns that signal.
#[stable(feature = "rust1", since = "1.0.0")]
fn signal(&self) -> Option<i32>;
}
#[stable(feature = "rust1", since = "1.0.0")]
impl ExitStatusExt for process::ExitStatus {
fn from_raw(raw: i32) -> Self {
process::ExitStatus::from_inner(From::from(raw))
}
fn signal(&self) -> Option<i32> {
self.as_inner().signal()
}
}
#[stable(feature = "process_extensions", since = "1.2.0")]
impl FromRawFd for process::Stdio {
unsafe fn from_raw_fd(fd: RawFd) -> process::Stdio {
let fd = sys::fd::FileDesc::new(fd);
let io = sys::process::Stdio::Fd(fd);
process::Stdio::from_inner(io)
}
}
#[stable(feature = "process_extensions", since = "1.2.0")]
impl AsRawFd for process::ChildStdin {
fn as_raw_fd(&self) -> RawFd {
self.as_inner().fd().raw()
}
}
#[stable(feature = "process_extensions", since = "1.2.0")]
impl AsRawFd for process::ChildStdout {
fn as_raw_fd(&self) -> RawFd {
self.as_inner().fd().raw()
}
}
#[stable(feature = "process_extensions", since = "1.2.0")]
impl AsRawFd for process::ChildStderr {
fn as_raw_fd(&self) -> RawFd {
self.as_inner().fd().raw()
}
}
#[stable(feature = "into_raw_os", since = "1.4.0")]
impl IntoRawFd for process::ChildStdin {
fn into_raw_fd(self) -> RawFd {
self.into_inner().into_fd().into_raw()
}
}
#[stable(feature = "into_raw_os", since = "1.4.0")]
impl IntoRawFd for process::ChildStdout {
fn into_raw_fd(self) -> RawFd {
self.into_inner().into_fd().into_raw()
}
}
#[stable(feature = "into_raw_os", since = "1.4.0")]
impl IntoRawFd for process::ChildStderr {
fn into_raw_fd(self) -> RawFd {
self.into_inner().into_fd().into_raw()
}
}
/// Returns the OS-assigned process identifier associated with this process's parent.
#[stable(feature = "unix_ppid", since = "1.27.0")]
pub fn parent_id() -> u32 {
crate::sys::os::getppid()
}