svn commit: r230430 - head/lib/libthr/thread

[Konstantin Belousov]

Author: kib
Date: Sat Jan 21 18:06:18 2012
New Revision: 230430
URL: http://svn.freebsd.org/changeset/base/230430

Log:
  Use getcontextx(3) internal API instead of getcontext(2) to provide
  the signal handlers with the context information in the deferrred
  case.
  
  Only enable the use of getcontextx(3) in the deferred signal delivery
  code on amd64 and i386. Sparc64 seems to have some undetermined issues
  with interaction of alloca(3) and signal delivery.
  
  Tested by:	flo (who also provided sparc64 harware access for me), pho
  Discussed with:	marius
  MFC after:	1 month

Modified:
  head/lib/libthr/thread/thr_sig.c

Modified: head/lib/libthr/thread/thr_sig.c
==============================================================================
--- head/lib/libthr/thread/thr_sig.c	Sat Jan 21 18:00:28 2012	(r230429)
+++ head/lib/libthr/thread/thr_sig.c	Sat Jan 21 18:06:18 2012	(r230430)
@@ -32,6 +32,7 @@
 #include <sys/signalvar.h>
 #include <signal.h>
 #include <errno.h>
+#include <stdlib.h>
 #include <string.h>
 #include <pthread.h>
 #include "un-namespace.h"
@@ -314,16 +315,24 @@ check_cancel(struct pthread *curthread, 
 static void
 check_deferred_signal(struct pthread *curthread)
 {
-	ucontext_t uc;
+	ucontext_t *uc;
 	struct sigaction act;
 	siginfo_t info;
 
 	if (__predict_true(curthread->deferred_siginfo.si_signo == 0))
 		return;
-	getcontext(&uc);
+
+#if defined(__amd64__) || defined(__i386__)
+	uc = alloca(__getcontextx_size());
+	__fillcontextx((char *)uc);
+#else
+	ucontext_t ucv;
+	uc = &ucv;
+	getcontext(uc);
+#endif
 	if (curthread->deferred_siginfo.si_signo != 0) {
 		act = curthread->deferred_sigact;
-		uc.uc_sigmask = curthread->deferred_sigmask;
+		uc->uc_sigmask = curthread->deferred_sigmask;
 		memcpy(&info, &curthread->deferred_siginfo, sizeof(siginfo_t));
 		/* remove signal */
 		curthread->deferred_siginfo.si_signo = 0;
@@ -334,7 +343,7 @@ check_deferred_signal(struct pthread *cu
 			tact.sa_handler = SIG_DFL;
 			_sigaction(info.si_signo, &tact, NULL);
 		}
-		handle_signal(&act, info.si_signo, &info, &uc);
+		handle_signal(&act, info.si_signo, &info, uc);
 	}
 }