1use crate::process::Pid;
2use crate::{backend, io};
3use bitflags::bitflags;
4
5bitflags! {
6    /// Options for modifying the behavior of wait/waitpid
7    pub struct WaitOptions: u32 {
8        /// Return immediately if no child has exited.
9        const NOHANG = backend::process::wait::WNOHANG as _;
10        /// Return if a child has stopped (but not traced via `ptrace(2)`)
11        const UNTRACED = backend::process::wait::WUNTRACED as _;
12        /// Return if a stopped child has been resumed by delivery of `SIGCONT`
13        const CONTINUED = backend::process::wait::WCONTINUED as _;
14    }
15}
16
17/// the status of the child processes the caller waited on
18#[derive(Debug, Clone, Copy)]
19pub struct WaitStatus(u32);
20
21impl WaitStatus {
22    /// create a `WaitStatus` out of an integer.
23    #[inline]
24    pub(crate) fn new(status: u32) -> Self {
25        Self(status)
26    }
27
28    /// Converts a `WaitStatus` into its raw representation as an integer.
29    #[inline]
30    pub const fn as_raw(self) -> u32 {
31        self.0
32    }
33
34    /// Returns whether the process is currently stopped.
35    #[inline]
36    pub fn stopped(self) -> bool {
37        backend::process::wait::WIFSTOPPED(self.0 as _)
38    }
39
40    /// Returns whether the process has continued from a job control stop.
41    #[inline]
42    pub fn continued(self) -> bool {
43        backend::process::wait::WIFCONTINUED(self.0 as _)
44    }
45
46    /// Returns the number of the signal that stopped the process,
47    /// if the process was stopped by a signal.
48    #[inline]
49    pub fn stopping_signal(self) -> Option<u32> {
50        if self.stopped() {
51            Some(backend::process::wait::WSTOPSIG(self.0 as _) as _)
52        } else {
53            None
54        }
55    }
56
57    /// Returns the exit status number returned by the process,
58    /// if it exited normally.
59    #[inline]
60    pub fn exit_status(self) -> Option<u32> {
61        if backend::process::wait::WIFEXITED(self.0 as _) {
62            Some(backend::process::wait::WEXITSTATUS(self.0 as _) as _)
63        } else {
64            None
65        }
66    }
67
68    /// Returns the number of the signal that terminated the process,
69    /// if the process was terminated by a signal.
70    #[inline]
71    pub fn terminating_signal(self) -> Option<u32> {
72        if backend::process::wait::WIFSIGNALED(self.0 as _) {
73            Some(backend::process::wait::WTERMSIG(self.0 as _) as _)
74        } else {
75            None
76        }
77    }
78}
79
80/// `waitpid(pid, waitopts)`—Wait for a specific process to change state.
81///
82/// If the pid is `None`, the call will wait for any child process whose
83/// process group id matches that of the calling process.
84///
85/// If the pid is equal to `RawPid::MAX`, the call will wait for any child
86/// process.
87///
88/// Otherwise if the `wrapping_neg` of pid is less than pid, the call will wait
89/// for any child process with a group ID equal to the `wrapping_neg` of `pid`.
90///
91/// Otherwise, the call will wait for the child process with the given pid.
92///
93/// On Success, returns the status of the selected process.
94///
95/// If `NOHANG` was specified in the options, and the selected child process
96/// didn't change state, returns `None`.
97///
98/// # References
99///  - [POSIX]
100///  - [Linux]
101///
102/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/wait.html
103/// [Linux]: https://man7.org/linux/man-pages/man2/waitpid.2.html
104#[cfg(not(target_os = "wasi"))]
105#[inline]
106pub fn waitpid(pid: Option<Pid>, waitopts: WaitOptions) -> io::Result<Option<WaitStatus>> {
107    Ok(backend::process::syscalls::waitpid(pid, waitopts)?.map(|(_, status)| status))
108}
109
110/// `wait(waitopts)`—Wait for any of the children of calling process to
111/// change state.
112///
113/// On success, returns the pid of the child process whose state changed, and
114/// the status of said process.
115///
116/// If `NOHANG` was specified in the options, and the selected child process
117/// didn't change state, returns `None`.
118///
119/// # References
120///  - [POSIX]
121///  - [Linux]
122///
123/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/wait.html
124/// [Linux]: https://man7.org/linux/man-pages/man2/waitpid.2.html
125#[cfg(not(target_os = "wasi"))]
126#[inline]
127pub fn wait(waitopts: WaitOptions) -> io::Result<Option<(Pid, WaitStatus)>> {
128    backend::process::syscalls::wait(waitopts)
129}
130