pty_info.rs

  1use alacritty_terminal::tty::Pty;
  2#[cfg(target_os = "windows")]
  3use std::num::NonZeroU32;
  4#[cfg(unix)]
  5use std::os::fd::AsRawFd;
  6use std::path::PathBuf;
  7
  8#[cfg(target_os = "windows")]
  9use windows::Win32::{Foundation::HANDLE, System::Threading::GetProcessId};
 10
 11use sysinfo::{Pid, Process, ProcessRefreshKind, RefreshKind, System, UpdateKind};
 12
 13struct ProcessIdGetter {
 14    handle: i32,
 15    fallback_pid: u32,
 16}
 17
 18#[cfg(unix)]
 19impl ProcessIdGetter {
 20    fn new(pty: &Pty) -> ProcessIdGetter {
 21        ProcessIdGetter {
 22            handle: pty.file().as_raw_fd(),
 23            fallback_pid: pty.child().id(),
 24        }
 25    }
 26
 27    fn pid(&self) -> Option<Pid> {
 28        let pid = unsafe { libc::tcgetpgrp(self.handle) };
 29        if pid < 0 {
 30            return Some(Pid::from_u32(self.fallback_pid));
 31        }
 32        Some(Pid::from_u32(pid as u32))
 33    }
 34}
 35
 36#[cfg(windows)]
 37impl ProcessIdGetter {
 38    fn new(pty: &Pty) -> ProcessIdGetter {
 39        let child = pty.child_watcher();
 40        let handle = child.raw_handle();
 41        let fallback_pid = child.pid().unwrap_or_else(|| unsafe {
 42            NonZeroU32::new_unchecked(GetProcessId(HANDLE(handle as _)))
 43        });
 44
 45        ProcessIdGetter {
 46            handle: handle as i32,
 47            fallback_pid: u32::from(fallback_pid),
 48        }
 49    }
 50
 51    fn pid(&self) -> Option<Pid> {
 52        let pid = unsafe { GetProcessId(HANDLE(self.handle as _)) };
 53        // the GetProcessId may fail and returns zero, which will lead to a stack overflow issue
 54        if pid == 0 {
 55            // in the builder process, there is a small chance, almost negligible,
 56            // that this value could be zero, which means child_watcher returns None,
 57            // GetProcessId returns 0.
 58            if self.fallback_pid == 0 {
 59                return None;
 60            }
 61            return Some(Pid::from_u32(self.fallback_pid));
 62        }
 63        Some(Pid::from_u32(pid))
 64    }
 65}
 66
 67#[derive(Clone, Debug)]
 68pub struct ProcessInfo {
 69    pub name: String,
 70    pub cwd: PathBuf,
 71    pub argv: Vec<String>,
 72}
 73
 74/// Fetches Zed-relevant Pseudo-Terminal (PTY) process information
 75pub struct PtyProcessInfo {
 76    system: System,
 77    refresh_kind: ProcessRefreshKind,
 78    pid_getter: ProcessIdGetter,
 79    pub current: Option<ProcessInfo>,
 80}
 81
 82impl PtyProcessInfo {
 83    pub fn new(pty: &Pty) -> PtyProcessInfo {
 84        let process_refresh_kind = ProcessRefreshKind::new()
 85            .with_cmd(UpdateKind::Always)
 86            .with_cwd(UpdateKind::Always)
 87            .with_exe(UpdateKind::Always);
 88        let refresh_kind = RefreshKind::new().with_processes(process_refresh_kind);
 89        let system = System::new_with_specifics(refresh_kind);
 90
 91        PtyProcessInfo {
 92            system,
 93            refresh_kind: process_refresh_kind,
 94            pid_getter: ProcessIdGetter::new(pty),
 95            current: None,
 96        }
 97    }
 98
 99    fn refresh(&mut self) -> Option<&Process> {
100        let pid = self.pid_getter.pid()?;
101        if self.system.refresh_processes_specifics(
102            sysinfo::ProcessesToUpdate::Some(&[pid]),
103            self.refresh_kind,
104        ) == 1
105        {
106            self.system.process(pid)
107        } else {
108            None
109        }
110    }
111
112    fn load(&mut self) -> Option<ProcessInfo> {
113        let process = self.refresh()?;
114        let cwd = process
115            .cwd()
116            .take()
117            .map_or(PathBuf::new(), |p| p.to_owned());
118
119        let info = ProcessInfo {
120            name: process.name().to_str()?.to_owned(),
121            cwd,
122            argv: process
123                .cmd()
124                .iter()
125                .filter_map(|s| s.to_str().map(ToOwned::to_owned))
126                .collect(),
127        };
128        self.current = Some(info.clone());
129        Some(info)
130    }
131
132    /// Updates the cached process info, returns whether the Zed-relevant info has changed
133    pub fn has_changed(&mut self) -> bool {
134        let current = self.load();
135        let has_changed = match (self.current.as_ref(), current.as_ref()) {
136            (None, None) => false,
137            (Some(prev), Some(now)) => prev.cwd != now.cwd || prev.name != now.name,
138            _ => true,
139        };
140        if has_changed {
141            self.current = current;
142        }
143        has_changed
144    }
145}