Add killpg #1034
Add killpg #1034
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| let res = unsafe { libc::killpg(pid.into(), | ||
| match signal.into() { | ||
| Some(s) => s as libc::c_int, | ||
| None => 0, |
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Why would you ever want to send 0? Is that even valid?
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It's valid. It just perform error checking and won't send any signal.
According to the POSIX spec of killpg:
If pgrp is greater than 1, killpg(pgrp, sig) shall be equivalent to kill(-pgrp, sig).
And in the POSIX spec of kill:
The signal to be sent is specified by sig and is either one from the list given in <signal.h> or 0. If sig is 0 (the null signal), error checking is performed but no signal is actually sent. The null signal can be used to check the validity of pid.
Also in the manpage of killpg:
On Linux, killpg() is implemented as a library function that makes the call kill(-pgrp, sig).
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Thanks for reviewing. Actually I just copy the implement of |
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@asomers I have added test & document. Can you review again please? |
| @@ -680,6 +680,8 @@ pub fn kill<T: Into<Option<Signal>>>(pid: ::unistd::Pid, signal: T) -> Result<() | |||
| Errno::result(res).map(drop) | |||
| } | |||
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| /// Send a signal to a process group [(see | |||
| /// killpg(3))](http://pubs.opengroup.org/onlinepubs/9699919799/functions/killpg.html). | |||
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The docs should say what the arguments mean. It's not obvious why signal should be an Option. Also, I see from the man page that killpg does something special when pgrp is 0. Perhaps that should be an option too?
test/sys/test_signal.rs
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| @@ -9,6 +9,11 @@ fn test_kill_none() { | |||
| kill(getpid(), None).expect("Should be able to send signal to myself."); | |||
| } | |||
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| #[test] | |||
| fn test_killpg_none() { | |||
| killpg(getpgrp(), None).expect("Should be able to send signal to my process group."); | |||
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@asomers I have update the document. Can you check again? |
src/sys/signal.rs
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| /// Send a signal to a process group [(see | ||
| /// killpg(3))](http://pubs.opengroup.org/onlinepubs/9699919799/functions/killpg.html). | ||
| /// | ||
| /// If `pgrp` less then or equal 1, the behavior is undefined. |
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In compiler-speak, "Undefined behavior" means something specific and very bad. It would be better to say "platform-specific".
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@asomers OK. I have updated it.
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Ok, looks good. It just needs a squash now. |
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Thanks again. I just squashed all commits. |
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Ahh, it looks like the PR I merged yesterday now conflicts with your CHANGELOG entry. I'm afraid you'll have to rebase. |
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OK. I think I fixed it. |
1034: Add killpg r=asomers a=DanSnow It's seem that #644 is inactively about 1 year. But I really want this API that can land in nix. Actually I not really understand how to check the availability of an API for other platform except Linux. But I saw that this API in `libc` is wrapping inside a `#[cfg(unix)]`. So I don't need to add any `#[cfg]` on this API, am I right? Resolved #644 Co-authored-by: DanSnow <dododavid006@gmail.com>
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It's seem that #644 is inactively about 1 year. But I really want this API that can land in nix.
Actually I not really understand how to check the availability of an API for other platform except Linux. But I saw that this API in
libcis wrapping inside a#[cfg(unix)]. So I don't need to add any#[cfg]on this API, am I right?Resolved #644