Add sigaltstack() prototype - Round 2

[Joel Sherrill]

Hi

The RTEMS Project has been porting more and more FreeBSD code
for capabilities like IPV6, USB, and user level commands. We are
trying very hard not to have to modify the source code as we
move it over. Some of the kernel code we have brought over
resulted in this needing to be added.

I first proposed v1 of this patch 2 years ago and dropped it.
I attempted address those comments though. See the other
recent thread.

This method is defined here:

http://pubs.opengroup.org/onlinepubs/009695399/functions/sigaltstack.html

One odd thing is that newlib uses <sys/signal.h> for <signal.h> prototypes
so I followed the pattern.   Not much really to the patch. It adds:

+ typedef struct  sigaltstack {...} stack_t
+ sigaltstack() prototype protected

The big question (as always) is whether or not the guards on the methods
are correct.

2014-08-15 Joel Sherrill <joel.sherrill@oarcorp.com>

    * libc/include/sys/signal.h: Add sigaltstack() support.


-- 
Joel Sherrill, Ph.D.             Director of Research & Development
joel.sherrill@OARcorp.com        On-Line Applications Research
Ask me about RTEMS: a free RTOS  Huntsville AL 35805
Support Available                (256) 722-9985

-------------- next part --------------
Index: newlib/libc/include/sys/signal.h
===================================================================
RCS file: /cvs/src/src/newlib/libc/include/sys/signal.h,v
retrieving revision 1.22
diff -u -r1.22 signal.h
--- newlib/libc/include/sys/signal.h	26 Oct 2012 09:23:46 -0000	1.22
+++ newlib/libc/include/sys/signal.h	14 Aug 2014 22:58:01 -0000
@@ -104,6 +104,17 @@
 #define sa_sigaction  _signal_handlers._sigaction
 #endif
 
+#if __BSD_VISIBLE || __XSI_VISIBLE || __POSIX_VISIBLE >= 200112
+/*
+ * Structure used in sigaltstack call.
+ */
+typedef struct sigaltstack {
+  void     *ss_sp;    /* Stack base or pointer.  */
+  int       ss_flags; /* Flags.  */
+  size_t    ss_size;  /* Stack size.  */
+} stack_t;
+#endif
+
 #elif defined(__CYGWIN__)
 #include <cygwin/signal.h>
 #else
@@ -161,6 +172,11 @@
 int _EXFUN(sigsuspend, (const sigset_t *));
 int _EXFUN(sigpause, (int));
 
+
+#if __BSD_VISIBLE || __XSI_VISIBLE || __POSIX_VISIBLE >= 200112
+int _EXFUN(sigaltstack, (const stack_t *__restrict, stack_t *__restrict));
+#endif
+
 #if defined(_POSIX_THREADS)
 #ifdef __CYGWIN__
 #  ifndef _CYGWIN_TYPES_H