Switch libc from using _sig{procmask,action,suspend} symbols, which

are aliases for the syscall stubs and are plt-interposed, to the
libc-private aliases of internally interposed sigprocmask() etc.

Since e.g. _sigaction is not interposed by libthr, calling signal()
removes thr_sighandler() from the handler slot etc.  The result was
breaking signal semantic and rtld locking.

The added __libc_sigprocmask and other symbols are hidden, they are
not exported and cannot be called through PLT.  The setjmp/longjmp
functions for x86 were changed to use direct calls, and since
PIC_PROLOGUE only needed for functional PLT indirection on i386, it is
removed as well.

The PowerPC bug of calling the syscall directly in the setjmp/longjmp
implementation is kept as is.

Reported by:	Pete French <petefrench@ingresso.co.uk>
Tested by:	Michiel Boland <boland37@xs4all.nl>
Reviewed by:	jilles (previous version)
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week

1 files changed, 3 insertions, 4 deletions

diff --git a/lib/libc/gen/siginterrupt.c b/lib/libc/gen/siginterrupt.c
index fde33ca567ce..d99b77233786 100644
--- a/lib/libc/gen/siginterrupt.c
+++ b/lib/libc/gen/siginterrupt.c
@@ -43,14 +43,13 @@ __FBSDID("$FreeBSD$");
  * after an instance of the indicated signal.
  */
 int
-siginterrupt(sig, flag)
-	int sig, flag;
+siginterrupt(int sig, int flag)
 {
 	extern sigset_t _sigintr __hidden;
 	struct sigaction sa;
 	int ret;
 
-	if ((ret = _sigaction(sig, (struct sigaction *)0, &sa)) < 0)
+	if ((ret = __libc_sigaction(sig, (struct sigaction *)0, &sa)) < 0)
 		return (ret);
 	if (flag) {
 		sigaddset(&_sigintr, sig);
@@ -59,5 +58,5 @@ siginterrupt(sig, flag)
 		sigdelset(&_sigintr, sig);
 		sa.sa_flags |= SA_RESTART;
 	}
-	return (_sigaction(sig, &sa, (struct sigaction *)0));
+	return (__libc_sigaction(sig, &sa, (struct sigaction *)0));
 }