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[PATCH 2/3] Make mcontext and stack information available to 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: Tue, 31 Mar 2015 18:46:53 +0100
- Subject: [PATCH 2/3] Make mcontext and stack information available to signal handlers
- Authentication-results: sourceware.org; auth=none
- References: <1427824014-19504-1-git-send-email-jon dot turney at dronecode dot org dot uk>
Add ucontext.h header, defining ucontext_t and mcontext_t types.
Provide sigaction sighandlers with a ucontext_t parameter, containing stack and
context information.
XXX: How do we indicate context information is not available (si_cyg == NULL)
* include/sys/ucontext.h : New header.
* include/ucontext.h : Ditto.
* exceptions.cc (call_signal_handler): Provide ucontext_t
parameter to signal handler function.
---
winsup/cygwin/ChangeLog | 7 +++++++
winsup/cygwin/exceptions.cc | 20 ++++++++++++++++++--
winsup/cygwin/include/sys/ucontext.h | 26 ++++++++++++++++++++++++++
winsup/cygwin/include/ucontext.h | 16 ++++++++++++++++
4 files changed, 67 insertions(+), 2 deletions(-)
create mode 100644 winsup/cygwin/include/sys/ucontext.h
create mode 100644 winsup/cygwin/include/ucontext.h
diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index 1b4f4f3..f037112 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,5 +1,12 @@
2015-03-30 Jon TURNEY <jon.turney@dronecode.org.uk>
+ * include/sys/ucontext.h : New header.
+ * include/ucontext.h : Ditto.
+ * exceptions.cc (call_signal_handler): Provide ucontext_t
+ parameter to signal handler function.
+
+2015-03-30 Jon TURNEY <jon.turney@dronecode.org.uk>
+
* include/cygwin/signal.h : Rename struct ucontext to struct
__mcontext. Remove unused member _internal. Fix differences from
the Win32 API CONTEXT type.
diff --git a/winsup/cygwin/exceptions.cc b/winsup/cygwin/exceptions.cc
index af53457..1c15bae 100644
--- a/winsup/cygwin/exceptions.cc
+++ b/winsup/cygwin/exceptions.cc
@@ -16,6 +16,7 @@ details. */
#include <stdlib.h>
#include <syslog.h>
#include <wchar.h>
+#include <ucontext.h>
#include "cygtls.h"
#include "pinfo.h"
@@ -1487,8 +1488,24 @@ _cygtls::call_signal_handler ()
/* Save information locally on stack to pass to handler. */
int thissig = sig;
siginfo_t thissi = infodata;
+ ucontext_t *thiscontext = NULL;
void (*thisfunc) (int, siginfo_t *, void *) = func;
+ ucontext_t context;
+ thiscontext = &context;
+ memset (&context, 0, sizeof(ucontext_t));
+ if (thissi.si_cyg)
+ {
+ memcpy (&context.uc_mcontext, ((cygwin_exception *)thissi.si_cyg)->context(), sizeof(CONTEXT));
+ }
+
+ 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;
+
sigset_t this_oldmask = set_process_mask_delta ();
int this_errno = saved_errno;
reset_signal_arrived ();
@@ -1496,8 +1513,7 @@ _cygtls::call_signal_handler ()
sig = 0; /* Flag that we can accept another signal */
unlock (); /* unlock signal stack */
- /* no ucontext_t information provided yet, so third arg is NULL */
- thisfunc (thissig, &thissi, NULL);
+ thisfunc (thissig, &thissi, thiscontext);
incyg = true;
set_signal_mask (_my_tls.sigmask, this_oldmask);
diff --git a/winsup/cygwin/include/sys/ucontext.h b/winsup/cygwin/include/sys/ucontext.h
new file mode 100644
index 0000000..ef0e849
--- /dev/null
+++ b/winsup/cygwin/include/sys/ucontext.h
@@ -0,0 +1,26 @@
+/* ucontext.h
+
+ Copyright 2015 Red Hat, Inc.
+
+This file is part of Cygwin.
+
+This software is a copyrighted work licensed under the terms of the
+Cygwin license. Please consult the file "CYGWIN_LICENSE" for
+details. */
+
+#ifndef _SYS_UCONTEXT_H_
+#define _SYS_UCONTEXT_H_
+
+#include <cygwin/signal.h>
+#include <sys/signal.h>
+
+typedef struct __mcontext mcontext_t;
+
+typedef struct __ucontext {
+ struct __ucontext *uc_link;
+ sigset_t uc_sigmask;
+ stack_t uc_stack;
+ mcontext_t uc_mcontext;
+} ucontext_t;
+
+#endif /* !_SYS_UCONTEXT_H_ */
diff --git a/winsup/cygwin/include/ucontext.h b/winsup/cygwin/include/ucontext.h
new file mode 100644
index 0000000..4240597
--- /dev/null
+++ b/winsup/cygwin/include/ucontext.h
@@ -0,0 +1,16 @@
+/* ucontext.h
+
+ Copyright 2015 Red Hat, Inc.
+
+This file is part of Cygwin.
+
+This software is a copyrighted work licensed under the terms of the
+Cygwin license. Please consult the file "CYGWIN_LICENSE" for
+details. */
+
+#ifndef _UCONTEXT_H
+#define _UCONTEXT_H
+
+#include <sys/ucontext.h>
+
+#endif /* _UCONTEXT_H */
--
2.1.4