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, 4 insertions, 4 deletions

diff --git a/lib/libc/gen/daemon.c b/lib/libc/gen/daemon.c
index b359a87..15c6f4a 100644
--- a/lib/libc/gen/daemon.c
+++ b/lib/libc/gen/daemon.c
@@ -41,10 +41,10 @@ __FBSDID("$FreeBSD$");
 #include <signal.h>
 #include <unistd.h>
 #include "un-namespace.h"
+#include "libc_private.h"
 
 int
-daemon(nochdir, noclose)
-	int nochdir, noclose;
+daemon(int nochdir, int noclose)
 {
 	struct sigaction osa, sa;
 	int fd;
@@ -56,7 +56,7 @@ daemon(nochdir, noclose)
 	sigemptyset(&sa.sa_mask);
 	sa.sa_handler = SIG_IGN;
 	sa.sa_flags = 0;
-	osa_ok = _sigaction(SIGHUP, &sa, &osa);
+	osa_ok = __libc_sigaction(SIGHUP, &sa, &osa);
 
 	switch (fork()) {
 	case -1:
@@ -74,7 +74,7 @@ daemon(nochdir, noclose)
 	newgrp = setsid();
 	oerrno = errno;
 	if (osa_ok != -1)
-		_sigaction(SIGHUP, &osa, NULL);
+		__libc_sigaction(SIGHUP, &osa, NULL);
 
 	if (newgrp == -1) {
 		errno = oerrno;