Skip to content
Snippets Groups Projects
Commit 89742f1f authored by Yuya Nishihara's avatar Yuya Nishihara
Browse files

rust-chg: install signal handlers to forward signals to server

I use sync::Once as a synchronization primitive because it's quite easy
to use, and is good enough to prevent data race in these C functions.
parent e70b616a
No related branches found
No related tags found
No related merge requests found
......@@ -10,6 +10,7 @@
use chg::{ChgClientExt, ChgUiHandler};
use chg::locator;
use chg::procutil;
use futures::sync::oneshot;
use std::env;
use std::io;
......@@ -38,6 +39,12 @@
client.attach_io(io::stdin(), io::stdout(), io::stderr())
})
.and_then(|client| {
let pid = client.server_spec().process_id.unwrap();
let pgid = client.server_spec().process_group_id;
procutil::setup_signal_handler_once(pid, pgid)?;
Ok(client)
})
.and_then(|client| {
client.run_command_chg(handler, env::args_os().skip(1))
})
.map(|(_client, _handler, code)| {
......@@ -41,6 +48,7 @@
client.run_command_chg(handler, env::args_os().skip(1))
})
.map(|(_client, _handler, code)| {
procutil::restore_signal_handler_once()?;
Ok(code)
})
.or_else(|err| Ok(Err(err))) // pass back error to caller
......
......@@ -5,6 +5,6 @@
//! Low-level utility for signal and process handling.
use libc::{self, c_int, size_t, ssize_t};
use libc::{self, c_int, pid_t, size_t, ssize_t};
use std::io;
use std::os::unix::io::RawFd;
......@@ -9,7 +9,8 @@
use std::io;
use std::os::unix::io::RawFd;
use std::sync;
#[link(name = "procutil", kind = "static")]
extern "C" {
// sendfds.c
fn sendfds(sockfd: c_int, fds: *const c_int, fdlen: size_t) -> ssize_t;
......@@ -11,8 +12,12 @@
#[link(name = "procutil", kind = "static")]
extern "C" {
// sendfds.c
fn sendfds(sockfd: c_int, fds: *const c_int, fdlen: size_t) -> ssize_t;
// sighandlers.c
fn setupsignalhandler(pid: pid_t, pgid: pid_t) -> c_int;
fn restoresignalhandler() -> c_int;
}
/// Returns the effective uid of the current process.
......@@ -41,3 +46,42 @@
}
Ok(())
}
static SETUP_SIGNAL_HANDLER: sync::Once = sync::Once::new();
static RESTORE_SIGNAL_HANDLER: sync::Once = sync::Once::new();
/// Installs signal handlers to forward signals to the server.
///
/// # Safety
///
/// This touches global states, and thus synchronized as a one-time
/// initialization function.
pub fn setup_signal_handler_once(pid: u32, pgid: Option<u32>) -> io::Result<()> {
let pid_signed = pid as i32;
let pgid_signed = pgid.map(|n| n as i32).unwrap_or(0);
let mut r = 0;
SETUP_SIGNAL_HANDLER.call_once(|| {
r = unsafe { setupsignalhandler(pid_signed, pgid_signed) };
});
if r < 0 {
return Err(io::Error::last_os_error());
}
Ok(())
}
/// Restores the original signal handlers.
///
/// # Safety
///
/// This touches global states, and thus synchronized as a one-time
/// initialization function.
pub fn restore_signal_handler_once() -> io::Result<()> {
let mut r = 0;
RESTORE_SIGNAL_HANDLER.call_once(|| {
r = unsafe { restoresignalhandler() };
});
if r < 0 {
return Err(io::Error::last_os_error());
}
Ok(())
}
0% Loading or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment