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Re: [patch/rfa]: Make sigsetjmp/siglongjmp thread-aware (was Re: [patch/rfa]: Add _setjmp/_longjmp macros)

Corinna Vinschen wrote:
On Jan 13 17:32, Corinna Vinschen wrote:

SUSv3 defines a _setjmp/_longjmp pair of functions, which are equivalent
to setjmp/longjmp, except that they shall never manipulate the signal

The below patch adds _setjmp and _longjmp as macros calling

I just found another potential problem with sigsetjmp/siglongjmp. Both macros are using the sigprocmask function to set and restore the signal mask. However, the usage of sigprocmask is unspecified in multi-threaded processes. See

So it looks like the implementation of sigsetjmp/siglongjmp is incorrect
for multi-threaded applications.  Below you'll find a new patch for the
machine/setjmp.h file.  It uses pthread_sigmask instead of sigprocmask
if _POSIX_THREADS is defined, sigprocmask otherwise.  This patch also
contains the patch I sent yesterday.

Tested on Cygwin. Ok to apply?

Yes, go ahead. Thanks.

-- Jeff J.

Thanks, Corinna

* libc/include/machine/setjmp.h (__SIGMASK_FUNC): Define as pthread_sigmask or sigprocmask depending on _POSIX_THREADS. (sigsetjmp): Use __SIGMASK_FUNC. (siglongjmp): Ditto. (_setjmp): Define as macro. (_longjmp): Ditto.

Index: libc/include/machine/setjmp.h
RCS file: /cvs/src/src/newlib/libc/include/machine/setjmp.h,v
retrieving revision 1.34
diff -u -p -r1.34 setjmp.h
--- libc/include/machine/setjmp.h 7 Nov 2007 21:42:24 -0000 1.34
+++ libc/include/machine/setjmp.h 14 Jan 2008 18:18:23 -0000
@@ -268,6 +268,12 @@ typedef int sigjmp_buf[_JBLEN+2];
+#define __SIGMASK_FUNC pthread_sigmask
+#define __SIGMASK_FUNC sigprocmask
#if defined(__GNUC__)
#define sigsetjmp(env, savemask) \
@@ -275,7 +281,7 @@ typedef int sigjmp_buf[_JBLEN+2];
({ \
sigjmp_buf *_sjbuf = &(env); \
((*_sjbuf)[_SAVEMASK] = savemask,\
- sigprocmask (SIG_SETMASK, 0, (sigset_t *)((*_sjbuf) + _SIGMASK)),\
+ __SIGMASK_FUNC (SIG_SETMASK, 0, (sigset_t *)((*_sjbuf) + _SIGMASK)),\
setjmp (*_sjbuf)); \
@@ -284,7 +290,7 @@ typedef int sigjmp_buf[_JBLEN+2];
({ \
sigjmp_buf *_sjbuf = &(env); \
((((*_sjbuf)[_SAVEMASK]) ? \
- sigprocmask (SIG_SETMASK, (sigset_t *)((*_sjbuf) + _SIGMASK), 0)\
+ __SIGMASK_FUNC (SIG_SETMASK, (sigset_t *)((*_sjbuf) + _SIGMASK), 0)\
: 0), \
longjmp (*_sjbuf, val)); \
@@ -292,15 +298,21 @@ typedef int sigjmp_buf[_JBLEN+2];
#else /* !__GNUC__ */
#define sigsetjmp(env, savemask) ((env)[_SAVEMASK] = savemask,\
- sigprocmask (SIG_SETMASK, 0, (sigset_t *) ((env) + _SIGMASK)),\
+ __SIGMASK_FUNC (SIG_SETMASK, 0, (sigset_t *) ((env) + _SIGMASK)),\
setjmp (env))
#define siglongjmp(env, val) ((((env)[_SAVEMASK])?\
- sigprocmask (SIG_SETMASK, (sigset_t *) ((env) + _SIGMASK), 0):0),\
+ __SIGMASK_FUNC (SIG_SETMASK, (sigset_t *) ((env) + _SIGMASK), 0):0),\
longjmp (env, val))
+/* POSIX _setjmp/_longjmp macros, maintained for XSI compatibility. These
+ are equivalent to sigsetjmp/siglongjmp when not saving the signal mask.
+ New applications should use sigsetjmp/siglongjmp instead. */
+#define _setjmp(env) sigsetjmp ((env), 0)
+#define _longjmp(env, val) siglongjmp ((env), (val))
#ifdef __cplusplus

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