      1
      2
      3
      4
      5
      6
      7
      8
      9
     10
     11
     12
     13
     14
     15
     16
     17
     18
     19
     20
     21
     22
     23
     24
     25
     26
     27
     28
     29
     30
     31
     32
     33
     34
     35
     36
     37
     38
     39
     40
     41
     42
     43
     44
     45
     46
     47
     48
     49
     50
     51
     52
     53
     54
     55
     56
     57
     58
     59
     60
     61
     62
     63
     64
     65
     66
     67
     68
     69
     70
     71
     72
     73
     74
     75
     76
     77
     78
     79
     80
     81
     82
     83
     84
     85
     86
     87
     88
     89
     90
     91
     92
     93
     94
     95
     96
     97
     98
     99
    100
    101
    102
    103
    104
    105
    106
    107
    108
    109
    110
    111
    112
    113
    114
    115
    116
    117
    118
    119
    120
    121
    122
    123
    124
    125
    126
    127
    128
    129
    130
    131
    132
    133
    134
    135
    136
    137
    138
    139
    140
    141
    142
    143
    144
    145
    146
    147
    148
    149
    150
    151
    152
    153
    154
    155
    156
    157
    158
    159
    160
    161
    162
    163
    164
    165
    166
    167
    168
    169
    170
    171
    172
    173
    174
    175
    176
    177
    178
    179
    180
    181
    182
    183
    184
    185
    186
    187
    188
    189
    190
    191
    192
    193
    194
    195
    196
    197
    198
    199
    200
    201
    202
    203
    204
    205
    206
    207
    208
    209
    210
    211
    212
    213
    214
    215
    216
    217
    218
    219
    220
    221
    222
    223
    224
    225
    226
    227
    228
    229
    230
    231
    232
    233
    234
    235
    236
    237
    238
    239

    use libc::{self, c_int};
    use Result;
    use errno::Errno;
    use unistd::Pid;

    use sys::signal::Signal;

    libc_bitflags!(
        pub struct WaitPidFlag: c_int {
            WNOHANG;
            WUNTRACED;
            #[cfg(any(target_os = "android",
                      target_os = "freebsd",
                      target_os = "haiku",
                      target_os = "ios",
                      target_os = "linux",
                      target_os = "macos",
                      target_os = "netbsd"))]
            WEXITED;
            WCONTINUED;
            #[cfg(any(target_os = "android",
                      target_os = "freebsd",
                      target_os = "haiku",
                      target_os = "ios",
                      target_os = "linux",
                      target_os = "macos",
                      target_os = "netbsd"))]
            WSTOPPED;
            /// Don't reap, just poll status.
            #[cfg(any(target_os = "android",
                      target_os = "freebsd",
                      target_os = "haiku",
                      target_os = "ios",
                      target_os = "linux",
                      target_os = "macos",
                      target_os = "netbsd"))]
            WNOWAIT;
            /// Don't wait on children of other threads in this group
            #[cfg(any(target_os = "android", target_os = "linux"))]
            __WNOTHREAD;
            /// Wait on all children, regardless of type
            #[cfg(any(target_os = "android", target_os = "linux"))]
            __WALL;
            #[cfg(any(target_os = "android", target_os = "linux"))]
            __WCLONE;
        }
    );

    /// Possible return values from `wait()` or `waitpid()`.
    ///
    /// Each status (other than `StillAlive`) describes a state transition
    /// in a child process `Pid`, such as the process exiting or stopping,
    /// plus additional data about the transition if any.
    ///
    /// Note that there are two Linux-specific enum variants, `PtraceEvent`
    /// and `PtraceSyscall`. Portable code should avoid exhaustively
    /// matching on `WaitStatus`.
    #[derive(Eq, PartialEq, Clone, Copy, Debug)]
    pub enum WaitStatus {
        /// The process exited normally (as with `exit()` or returning from
        /// `main`) with the given exit code. This case matches the C macro
        /// `WIFEXITED(status)`; the second field is `WEXITSTATUS(status)`.
        Exited(Pid, i32),
        /// The process was killed by the given signal. The third field
        /// indicates whether the signal generated a core dump. This case
        /// matches the C macro `WIFSIGNALED(status)`; the last two fields
        /// correspond to `WTERMSIG(status)` and `WCOREDUMP(status)`.
        Signaled(Pid, Signal, bool),
        /// The process is alive, but was stopped by the given signal. This
        /// is only reported if `WaitPidFlag::WUNTRACED` was passed. This
        /// case matches the C macro `WIFSTOPPED(status)`; the second field
        /// is `WSTOPSIG(status)`.
        Stopped(Pid, Signal),
        /// The traced process was stopped by a `PTRACE_EVENT_*` event. See
        /// [`nix::sys::ptrace`] and [`ptrace`(2)] for more information. All
        /// currently-defined events use `SIGTRAP` as the signal; the third
        /// field is the `PTRACE_EVENT_*` value of the event.
        ///
        /// [`nix::sys::ptrace`]: ../ptrace/index.html
        /// [`ptrace`(2)]: http://man7.org/linux/man-pages/man2/ptrace.2.html
        #[cfg(any(target_os = "linux", target_os = "android"))]
        PtraceEvent(Pid, Signal, c_int),
        /// The traced process was stopped by execution of a system call,
        /// and `PTRACE_O_TRACESYSGOOD` is in effect. See [`ptrace`(2)] for
        /// more information.
        ///
        /// [`ptrace`(2)]: http://man7.org/linux/man-pages/man2/ptrace.2.html
        #[cfg(any(target_os = "linux", target_os = "android"))]
        PtraceSyscall(Pid),
        /// The process was previously stopped but has resumed execution
        /// after receiving a `SIGCONT` signal. This is only reported if
        /// `WaitPidFlag::WCONTINUED` was passed. This case matches the C
        /// macro `WIFCONTINUED(status)`.
        Continued(Pid),
        /// There are currently no state changes to report in any awaited
        /// child process. This is only returned if `WaitPidFlag::WNOHANG`
        /// was used (otherwise `wait()` or `waitpid()` would block until
        /// there was something to report).
        StillAlive,
    }

    impl WaitStatus {
        /// Extracts the PID from the WaitStatus unless it equals StillAlive.
        pub fn pid(&self) -> Option<Pid> {
            use self::WaitStatus::*;
            match *self {
                Exited(p, _)  | Signaled(p, _, _) |
                    Stopped(p, _) | Continued(p) => Some(p),
                StillAlive => None,
                #[cfg(any(target_os = "android", target_os = "linux"))]
                PtraceEvent(p, _, _) | PtraceSyscall(p) => Some(p),
            }
        }
    }

    fn exited(status: i32) -> bool {
        unsafe { libc::WIFEXITED(status) }
    }

    fn exit_status(status: i32) -> i32 {
        unsafe { libc::WEXITSTATUS(status) }
    }

    fn signaled(status: i32) -> bool {
        unsafe { libc::WIFSIGNALED(status) }
    }

    fn term_signal(status: i32) -> Result<Signal> {
        Signal::from_c_int(unsafe { libc::WTERMSIG(status) })
    }

    fn dumped_core(status: i32) -> bool {
        unsafe { libc::WCOREDUMP(status) }
    }

    fn stopped(status: i32) -> bool {
        unsafe { libc::WIFSTOPPED(status) }
    }

    fn stop_signal(status: i32) -> Result<Signal> {
        Signal::from_c_int(unsafe { libc::WSTOPSIG(status) })
    }

    #[cfg(any(target_os = "android", target_os = "linux"))]
    fn syscall_stop(status: i32) -> bool {
        // From ptrace(2), setting PTRACE_O_TRACESYSGOOD has the effect
        // of delivering SIGTRAP | 0x80 as the signal number for syscall
        // stops. This allows easily distinguishing syscall stops from
        // genuine SIGTRAP signals.
        unsafe { libc::WSTOPSIG(status) == libc::SIGTRAP | 0x80 }
    }

    #[cfg(any(target_os = "android", target_os = "linux"))]
    fn stop_additional(status: i32) -> c_int {
        (status >> 16) as c_int
    }

    fn continued(status: i32) -> bool {
        unsafe { libc::WIFCONTINUED(status) }
    }

    impl WaitStatus {
        /// Convert a raw `wstatus` as returned by `waitpid`/`wait` into a `WaitStatus`
        ///
        /// # Errors
        ///
        /// Returns an `Error` corresponding to `EINVAL` for invalid status values.
        ///
        /// # Examples
        ///
        /// Convert a `wstatus` obtained from `libc::waitpid` into a `WaitStatus`:
        ///
        /// ```
        /// use nix::sys::wait::WaitStatus;
        /// use nix::sys::signal::Signal;
        /// let pid = nix::unistd::Pid::from_raw(1);
        /// let status = WaitStatus::from_raw(pid, 0x0002);
        /// assert_eq!(status, Ok(WaitStatus::Signaled(pid, Signal::SIGINT, false)));
        /// ```
        pub fn from_raw(pid: Pid, status: i32) -> Result<WaitStatus> {
            Ok(if exited(status) {
                WaitStatus::Exited(pid, exit_status(status))
            } else if signaled(status) {
                WaitStatus::Signaled(pid, term_signal(status)?, dumped_core(status))
            } else if stopped(status) {
                cfg_if! {
                    if #[cfg(any(target_os = "android", target_os = "linux"))] {
                        fn decode_stopped(pid: Pid, status: i32) -> Result<WaitStatus> {
                            let status_additional = stop_additional(status);
                            Ok(if syscall_stop(status) {
                                WaitStatus::PtraceSyscall(pid)
                            } else if status_additional == 0 {
                                WaitStatus::Stopped(pid, stop_signal(status)?)
                            } else {
                                WaitStatus::PtraceEvent(pid, stop_signal(status)?,
                                                        stop_additional(status))
                            })
                        }
                    } else {
                        fn decode_stopped(pid: Pid, status: i32) -> Result<WaitStatus> {
                            Ok(WaitStatus::Stopped(pid, stop_signal(status)?))
                        }
                    }
                }
                return decode_stopped(pid, status);
            } else {
                assert!(continued(status));
                WaitStatus::Continued(pid)
            })
        }
    }

    pub fn waitpid<P: Into<Option<Pid>>>(pid: P, options: Option<WaitPidFlag>) -> Result<WaitStatus> {
        use self::WaitStatus::*;

        let mut status: i32 = 0;

        let option_bits = match options {
            Some(bits) => bits.bits(),
            None => 0,
        };

        let res = unsafe {
            libc::waitpid(
                pid.into().unwrap_or(Pid::from_raw(-1)).into(),
                &mut status as *mut c_int,
                option_bits,
            )
        };

        match Errno::result(res)? {
            0 => Ok(StillAlive),
            res => WaitStatus::from_raw(Pid::from_raw(res), status),
        }
    }

    pub fn wait() -> Result<WaitStatus> {
        waitpid(None, None)
    }

# Help

## Keyboard Shortcuts

`?`
  Show this help dialog
`S`
  Focus the search field
`↑`
  Move up in search results
`↓`
  Move down in search results
`↹`
  Switch tab
`⏎`
  Go to active search result
`+`
  Expand all sections
`-`
  Collapse all sections

## Search Tricks

Prefix searches with a type followed by a colon (e.g., `fn:`) to restrict the search to a given type.

Accepted types are: `fn`, `mod`, `struct`, `enum`, `trait`, `type`, `macro`, and `const`.

Search functions by type signature (e.g., `vec -> usize` or `* -> vec`)

Search multiple things at once by splitting your query with comma (e.g., `str,u8` or `String,struct:Vec,test`)