async_process/
unix.rs

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1//! Unix-specific extensions.
2
3use std::ffi::OsStr;
4use std::io;
5use std::os::unix::process::CommandExt as _;
6
7use crate::Command;
8
9/// Unix-specific extensions to the [`Command`] builder.
10///
11/// This trait is sealed: it cannot be implemented outside `async-process`.
12/// This is so that future additional methods are not breaking changes.
13pub trait CommandExt: crate::sealed::Sealed {
14    /// Sets the child process's user ID. This translates to a
15    /// `setuid` call in the child process. Failure in the `setuid`
16    /// call will cause the spawn to fail.
17    fn uid(&mut self, id: u32) -> &mut Command;
18
19    /// Similar to `uid`, but sets the group ID of the child process. This has
20    /// the same semantics as the `uid` field.
21    fn gid(&mut self, id: u32) -> &mut Command;
22
23    /// Performs all the required setup by this `Command`, followed by calling
24    /// the `execvp` syscall.
25    ///
26    /// On success this function will not return, and otherwise it will return
27    /// an error indicating why the exec (or another part of the setup of the
28    /// `Command`) failed.
29    ///
30    /// `exec` not returning has the same implications as calling
31    /// [`std::process::exit`] – no destructors on the current stack or any other
32    /// thread’s stack will be run. Therefore, it is recommended to only call
33    /// `exec` at a point where it is fine to not run any destructors. Note,
34    /// that the `execvp` syscall independently guarantees that all memory is
35    /// freed and all file descriptors with the `CLOEXEC` option (set by default
36    /// on all file descriptors opened by the standard library) are closed.
37    ///
38    /// This function, unlike `spawn`, will **not** `fork` the process to create
39    /// a new child. Like spawn, however, the default behavior for the stdio
40    /// descriptors will be to inherited from the current process.
41    ///
42    /// # Notes
43    ///
44    /// The process may be in a "broken state" if this function returns in
45    /// error. For example the working directory, environment variables, signal
46    /// handling settings, various user/group information, or aspects of stdio
47    /// file descriptors may have changed. If a "transactional spawn" is
48    /// required to gracefully handle errors it is recommended to use the
49    /// cross-platform `spawn` instead.
50    fn exec(&mut self) -> io::Error;
51
52    /// Set executable argument
53    ///
54    /// Set the first process argument, `argv[0]`, to something other than the
55    /// default executable path.
56    fn arg0<S>(&mut self, arg: S) -> &mut Command
57    where
58        S: AsRef<OsStr>;
59}
60
61impl crate::sealed::Sealed for Command {}
62impl CommandExt for Command {
63    fn uid(&mut self, id: u32) -> &mut Command {
64        self.inner.uid(id);
65        self
66    }
67
68    fn gid(&mut self, id: u32) -> &mut Command {
69        self.inner.gid(id);
70        self
71    }
72
73    fn exec(&mut self) -> io::Error {
74        self.inner.exec()
75    }
76
77    fn arg0<S>(&mut self, arg: S) -> &mut Command
78    where
79        S: AsRef<OsStr>,
80    {
81        self.inner.arg0(arg);
82        self
83    }
84}
async_process/unix.rs

async_process/
unix.rs
