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[PATCH] Only construct ucontext for SA_SIGINFO signal handlers
- From: Jon TURNEY <jon dot turney at dronecode dot org dot uk>
- To: cygwin-patches at cygwin dot com
- Cc: Jon TURNEY <jon dot turney at dronecode dot org dot uk>
- Date: Thu, 2 Apr 2015 20:30:41 +0100
- Subject: [PATCH] Only construct ucontext for SA_SIGINFO signal handlers
- Authentication-results: sourceware.org; auth=none
* exceptions.cc (call_signal_handler): Only bother to construct
the ucontext for signal handlers with SA_SIGINFO set.
Signed-off-by: Jon TURNEY <jon.turney@dronecode.org.uk>
---
winsup/cygwin/ChangeLog | 5 +++++
winsup/cygwin/exceptions.cc | 46 ++++++++++++++++++++++++++-------------------
2 files changed, 32 insertions(+), 19 deletions(-)
diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index 3b0e111..0ddc795 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,5 +1,10 @@
2015-04-02 Jon TURNEY <jon.turney@dronecode.org.uk>
+ * exceptions.cc (call_signal_handler): Only bother to construct
+ the ucontext for signal handlers with SA_SIGINFO set.
+
+2015-04-02 Jon TURNEY <jon.turney@dronecode.org.uk>
+
* include/cygwin/signal.h (struct __mcontext): 16-byte align.
* include/sys/ucontext.h (ucontext_t): Ditto.
diff --git a/winsup/cygwin/exceptions.cc b/winsup/cygwin/exceptions.cc
index 0d1f36d..bac550c 100644
--- a/winsup/cygwin/exceptions.cc
+++ b/winsup/cygwin/exceptions.cc
@@ -1490,33 +1490,41 @@ _cygtls::call_signal_handler ()
siginfo_t thissi = infodata;
void (*thisfunc) (int, siginfo_t *, void *) = func;
- ucontext_t thiscontext;
- thiscontext.uc_link = 0;
- thiscontext.uc_flags = 0;
- if (thissi.si_cyg)
- memcpy (&thiscontext.uc_mcontext, ((cygwin_exception *)thissi.si_cyg)->context(), sizeof(CONTEXT));
- else
- RtlCaptureContext ((CONTEXT *)&thiscontext.uc_mcontext);
- /* FIXME: Really this should be the context which the signal interrupted? */
-
- /* FIXME: If/when sigaltstack is implemented, this will need to do
- something more complicated */
- thiscontext.uc_stack.ss_sp = NtCurrentTeb ()->Tib.StackBase;
- thiscontext.uc_stack.ss_flags = 0;
- if (!NtCurrentTeb ()->DeallocationStack)
- thiscontext.uc_stack.ss_size = (uintptr_t)NtCurrentTeb ()->Tib.StackLimit - (uintptr_t)NtCurrentTeb ()->Tib.StackBase;
- else
- thiscontext.uc_stack.ss_size = (uintptr_t)NtCurrentTeb ()->DeallocationStack - (uintptr_t)NtCurrentTeb ()->Tib.StackBase;
+ ucontext_t context;
+ ucontext_t *thiscontext = NULL;
+
+ /* Only make a context for SA_SIGINFO handlers */
+ if (this_sa_flags & SA_SIGINFO)
+ {
+ context.uc_link = 0;
+ context.uc_flags = 0;
+ if (thissi.si_cyg)
+ memcpy (&context.uc_mcontext, ((cygwin_exception *)thissi.si_cyg)->context(), sizeof(CONTEXT));
+ else
+ RtlCaptureContext ((CONTEXT *)&context.uc_mcontext);
+ /* FIXME: Really this should be the context which the signal interrupted? */
+
+ /* FIXME: If/when sigaltstack is implemented, this will need to do
+ something more complicated */
+ context.uc_stack.ss_sp = NtCurrentTeb ()->Tib.StackBase;
+ context.uc_stack.ss_flags = 0;
+ if (!NtCurrentTeb ()->DeallocationStack)
+ context.uc_stack.ss_size = (uintptr_t)NtCurrentTeb ()->Tib.StackLimit - (uintptr_t)NtCurrentTeb ()->Tib.StackBase;
+ else
+ context.uc_stack.ss_size = (uintptr_t)NtCurrentTeb ()->DeallocationStack - (uintptr_t)NtCurrentTeb ()->Tib.StackBase;
+
+ thiscontext = &context;
+ }
sigset_t this_oldmask = set_process_mask_delta ();
- thiscontext.uc_sigmask = this_oldmask;
+ context.uc_sigmask = this_oldmask;
int this_errno = saved_errno;
reset_signal_arrived ();
incyg = false;
sig = 0; /* Flag that we can accept another signal */
unlock (); /* unlock signal stack */
- thisfunc (thissig, &thissi, &thiscontext);
+ thisfunc (thissig, &thissi, thiscontext);
incyg = true;
set_signal_mask (_my_tls.sigmask, this_oldmask);
--
2.1.4