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

3 files changed, 7 insertions, 3 deletions

diff --git a/sys/compat/ia32/ia32_signal.h b/sys/compat/ia32/ia32_signal.h
index e79100a..267d472 100644
--- a/sys/compat/ia32/ia32_signal.h
+++ b/sys/compat/ia32/ia32_signal.h
@@ -199,10 +199,12 @@ struct ia32_sigframe3 {
 };
 #endif
 
+struct ksiginfo;
 extern char ia32_sigcode[];
 extern char freebsd4_ia32_sigcode[];
 extern int sz_ia32_sigcode;
 extern int sz_freebsd4_ia32_sigcode;
-extern void ia32_sendsig(sig_t, int, sigset_t *, u_long);
+extern void ia32_sendsig(sig_t, struct ksiginfo *, sigset_t *);
 extern void ia32_setregs(struct thread *td, u_long entry, u_long stack,
     u_long ps_strings);
+extern void siginfo_to_ia32siginfo(siginfo_t *src, struct ia32_siginfo *dst);
diff --git a/sys/compat/linux/linux_misc.c b/sys/compat/linux/linux_misc.c
index eb9115d..4b85a43 100644
--- a/sys/compat/linux/linux_misc.c
+++ b/sys/compat/linux/linux_misc.c
@@ -862,7 +862,7 @@ linux_wait4(struct thread *td, struct linux_wait4_args *args)
 
 	p = td->td_proc;
 	PROC_LOCK(p);
-	SIGDELSET(p->p_siglist, SIGCHLD);
+	sigqueue_delete(&p->p_sigqueue, SIGCHLD);
 	PROC_UNLOCK(p);
 
 	if (args->status) {
diff --git a/sys/compat/svr4/svr4_signal.h b/sys/compat/svr4/svr4_signal.h
index c3230fb..218236d 100644
--- a/sys/compat/svr4/svr4_signal.h
+++ b/sys/compat/svr4/svr4_signal.h
@@ -133,10 +133,12 @@ struct svr4_sigaltstack {
 
 #define	SVR4_MINSIGSTKSZ	8192
 
+struct ksiginfo;
+
 void bsd_to_svr4_sigaltstack(const struct sigaltstack *, struct svr4_sigaltstack *);
 void bsd_to_svr4_sigset(const sigset_t *, svr4_sigset_t *);
 void svr4_to_bsd_sigaltstack(const struct svr4_sigaltstack *, struct sigaltstack *);
 void svr4_to_bsd_sigset(const svr4_sigset_t *, sigset_t *);
-void svr4_sendsig(sig_t, int, sigset_t  *, u_long);
+void svr4_sendsig(sig_t, struct ksiginfo *, sigset_t  *);
 
 #endif /* !_SVR4_SIGNAL_H_ */