Missing killpg

[mmstick]

Needed by Ion to send signals to all members of a process group.

[Susurrus]

@mmstick Would you be willing to file a PR adding this to nix? I'd be happy to mentor you through the process if you would. Always looking for new contributors!

[mmstick]

Sure. Where can I start?

[Susurrus]

The first step is actually to get killpg and all related constants into the https://github.com/rust-lang/libc repo for all appropriate targets (see the supported list of targets for nix in the README).

Once that's done, you can file a PR here adding killpg after kill in src/sys/signal.rs. Be sure to add doc comments and ideally a test if you could (spawn a new process group of something and try to kill it, which should work without sudo privileges I would think so it can be safely run in CI).

[SanchayanMaity]

@Susurrus killpg has two signatures.

int killpg(int pgrp, int sig);
int killpg(pid_t pgrp, int sig);

How to handle this? Or should the pid_t signature alone be sufficient? Do I understand correctly that the below change in rust libc alone is sufficient to carry this forward?.

diff --git a/src/unix/mod.rs b/src/unix/mod.rs
index 35a7f448..2e65b43c 100644
--- a/src/unix/mod.rs
+++ b/src/unix/mod.rs
@@ -562,6 +562,7 @@ extern {
     #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
                    link_name = "kill$UNIX2003")]
     pub fn kill(pid: pid_t, sig: ::c_int) -> ::c_int;
+    pub fn killpg(pgrp: pid_t, sig: ::c_int) -> ::c_int;
 
     pub fn mlock(addr: *const ::c_void, len: ::size_t) -> ::c_int;
     pub fn munlock(addr: *const ::c_void, len: ::size_t) -> ::c_int;

[asomers]

AFAIK pid_t is equal to int everywhere. But POSIX says that the first argument should be pid_t.. Your suggested patch looks correct to me.

[SanchayanMaity]

killpg in rust-lang/libc#879 is now merged.

[Susurrus]

@mmstick @SanchayanMaity With killpg in libc, please feel free to fille a PR adding this to all relevant platforms.

I too need killpkg for my project to kill all processes associated by group id since std::process::Child::kill() is not good enough for what I'm doing. It would be useful to have instead of relying on the libc crate.