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[newlib-cygwin] Add comment to sigaltstack to explain setting ss_flags here
- From: Corinna Vinschen <corinna at sourceware dot org>
- To: cygwin-cvs at sourceware dot org
- Date: 30 Jun 2015 18:44:01 -0000
- Subject: [newlib-cygwin] Add comment to sigaltstack to explain setting ss_flags here
https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=0f3e6315712428fcbfc0b6ffeec7c850d9b7206a
commit 0f3e6315712428fcbfc0b6ffeec7c850d9b7206a
Author: Corinna Vinschen <corinna@vinschen.de>
Date: Tue Jun 30 20:43:50 2015 +0200
Add comment to sigaltstack to explain setting ss_flags here
* signal.cc (sigaltstack): Add comment.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Diff:
---
winsup/cygwin/ChangeLog | 4 ++++
winsup/cygwin/signal.cc | 4 ++++
2 files changed, 8 insertions(+)
diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index 31b429b..01bb3eb 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,7 @@
+2015-06-30 Corinna Vinschen <corinna@vinschen.de>
+
+ * signal.cc (sigaltstack): Add comment.
+
2015-06-27 Corinna Vinschen <corinna@vinschen.de>
* exceptions.cc (_cygtls::call_signal_handler): Drop manipulating
diff --git a/winsup/cygwin/signal.cc b/winsup/cygwin/signal.cc
index 467c919..2b9cfda 100644
--- a/winsup/cygwin/signal.cc
+++ b/winsup/cygwin/signal.cc
@@ -670,6 +670,10 @@ sigaltstack (const stack_t *ss, stack_t *oss)
{
char stack_marker;
memcpy (oss, &me.altstack, sizeof *oss);
+ /* Check if the current stack is the alternate signal stack. If so,
+ set ss_flags accordingly. We do this here rather than setting
+ ss_flags in _cygtls::call_signal_handler since the signal handler
+ calls longjmp, so we never return to reset the flag. */
if (!me.altstack.ss_flags && me.altstack.ss_sp)
{
if (&stack_marker >= (char *) me.altstack.ss_sp