secmem-proc 0.3.8

/// Error that the `TracerPid` was not found in `/proc/self/status`.
#[derive(Debug, Clone, thiserror::Error)]
#[error("`TracerPid` entry not found in `/proc/self/status`")]
pub struct TracerPidNotFound;

/// Check whether the current process is being traced by reading
/// `/proc/self/status`. Returns the tracer pid or `0` if not traced.
#[cfg(target_os = "linux")]
fn get_tracer_pid() -> anyhow::Result<rustix::process::RawPid> {
    let fd = rustix_linux_procfs::proc_self_status()?;
    let file = std::fs::File::from(fd);
    let status = std::io::read_to_string(file)?;
    for line in status.lines() {
        if let Some(mut tracer_pid_str) = line.strip_prefix("TracerPid:") {
            tracer_pid_str = tracer_pid_str.trim();
            let raw_pid: rustix::process::RawPid = tracer_pid_str.parse()?;
            return Ok(raw_pid);
        }
    }
    Err(anyhow::Error::new(TracerPidNotFound))
}

/// Check whether the current process is being traced by reading
/// `/proc/self/status`.
#[cfg(target_os = "linux")]
pub fn is_tracer_present() -> anyhow::Result<Option<rustix::process::Pid>> {
    let raw_tracer_pid = get_tracer_pid()?;
    if raw_tracer_pid == 0 {
        Ok(None)
    } else {
        let pid = rustix::process::Pid::from_raw(raw_tracer_pid)
            .ok_or(anyhow::Error::new(TracerPidNotFound))?;
        Ok(Some(pid))
    }
}

#[cfg(test)]
mod tests {
    #[cfg(target_os = "linux")]
    use super::is_tracer_present;

    #[cfg(target_os = "linux")]
    #[test]
    fn test_tracer_nonpresent() {
        assert!(is_tracer_present()
            .expect("error checking for tracer")
            .is_none());
    }
}