1. Change prototype of trapsignal and sendsig to use ksiginfo_t *, most

   changes in MD code are trivial, before this change, trapsignal and
   sendsig use discrete parameters, now they uses member fields of
   ksiginfo_t structure. For sendsig, this change allows us to pass
   POSIX realtime signal value to user code.

2. Remove cpu_thread_siginfo, it is no longer needed because we now always
   generate ksiginfo_t data and feed it to libpthread.

3. Add p_sigqueue to proc structure to hold shared signals which were
   blocked by all threads in the proc.

4. Add td_sigqueue to thread structure to hold all signals delivered to
   thread.

5. i386 and amd64 now return POSIX standard si_code, other arches will
   be fixed.

6. In this sigqueue implementation, pending signal set is kept as before,
   an extra siginfo list holds additional siginfo_t data for signals.
   kernel code uses psignal() still behavior as before, it won't be failed
   even under memory pressure, only exception is when deleting a signal,
   we should call sigqueue_delete to remove signal from sigqueue but
   not SIGDELSET. Current there is no kernel code will deliver a signal
   with additional data, so kernel should be as stable as before,
   a ksiginfo can carry more information, for example, allow signal to
   be delivered but throw away siginfo data if memory is not enough.
   SIGKILL and SIGSTOP have fast path in sigqueue_add, because they can
   not be caught or masked.
   The sigqueue() syscall allows user code to queue a signal to target
   process, if resource is unavailable, EAGAIN will be returned as
   specification said.
   Just before thread exits, signal queue memory will be freed by
   sigqueue_flush.
   Current, all signals are allowed to be queued, not only realtime signals.

Earlier patch reviewed by: jhb, deischen
Tested on: i386, amd64

1 files changed, 2 insertions, 1 deletions

diff --git a/sys/kern/kern_thr.c b/sys/kern/kern_thr.c
index 0e8b3e8..e6661e2 100644
--- a/sys/kern/kern_thr.c
+++ b/sys/kern/kern_thr.c
@@ -279,6 +279,7 @@ thr_exit(struct thread *td, struct thr_exit_args *uap)
 		suword((void *)uap->state, 1);
 
 	PROC_LOCK(p);
+	sigqueue_flush(&td->td_sigqueue);
 	mtx_lock_spin(&sched_lock);
 
 	/*
@@ -319,7 +320,7 @@ thr_kill(struct thread *td, struct thr_kill_args *uap)
 		error = EINVAL;
 		goto out;
 	}
-	tdsignal(ttd, uap->sig, SIGTARGET_TD);
+	tdsignal(ttd, uap->sig, NULL, SIGTARGET_TD);
 out:
 	PROC_UNLOCK(p);
 	return (error);