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

22 files changed, 104 insertions, 121 deletions

diff --git a/lib/libc/amd64/gen/setjmp.S b/lib/libc/amd64/gen/setjmp.S
index c26f52f..826220e 100644
--- a/lib/libc/amd64/gen/setjmp.S
+++ b/lib/libc/amd64/gen/setjmp.S
@@ -55,7 +55,7 @@ ENTRY(setjmp)
 	movq	$0,%rsi			/* (sigset_t*)set  */
 	leaq	72(%rcx),%rdx		/* 9,10; (sigset_t*)oset */
 	/* stack is 16-byte aligned */
-	call	PIC_PLT(CNAME(_sigprocmask))
+	call	__libc_sigprocmask
 	popq	%rdi
 	movq	%rdi,%rcx
 	movq	0(%rsp),%rdx		/* retval */
@@ -82,7 +82,7 @@ ENTRY(__longjmp)
 	leaq	72(%rdx),%rsi		/* (sigset_t*)set  */
 	movq	$0,%rdx			/* (sigset_t*)oset */
 	subq	$0x8,%rsp		/* make the stack 16-byte aligned */
-	call	PIC_PLT(CNAME(_sigprocmask))
+	call	__libc_sigprocmask
 	addq	$0x8,%rsp
 	popq	%rsi
 	popq	%rdi			/* jmpbuf */
diff --git a/lib/libc/amd64/gen/sigsetjmp.S b/lib/libc/amd64/gen/sigsetjmp.S
index 9a20556..1e8e77c 100644
--- a/lib/libc/amd64/gen/sigsetjmp.S
+++ b/lib/libc/amd64/gen/sigsetjmp.S
@@ -63,7 +63,7 @@ ENTRY(sigsetjmp)
 	movq	$0,%rsi			/* (sigset_t*)set  */
 	leaq	72(%rcx),%rdx		/* 9,10 (sigset_t*)oset */
 	/* stack is 16-byte aligned */
-	call	PIC_PLT(CNAME(_sigprocmask))
+	call	__libc_sigprocmask
 	popq	%rdi
 2:	movq	%rdi,%rcx
 	movq	0(%rsp),%rdx		/* retval */
@@ -91,7 +91,7 @@ ENTRY(__siglongjmp)
 	leaq	72(%rdx),%rsi		/* (sigset_t*)set  */
 	movq	$0,%rdx			/* (sigset_t*)oset */
 	subq	$0x8,%rsp		/* make the stack 16-byte aligned */
-	call	PIC_PLT(CNAME(_sigprocmask))
+	call	__libc_sigprocmask
 	addq	$0x8,%rsp
 	popq	%rsi
 	popq	%rdi			/* jmpbuf */
diff --git a/lib/libc/compat-43/sigcompat.c b/lib/libc/compat-43/sigcompat.c
index 199846f..a8cef1c 100644
--- a/lib/libc/compat-43/sigcompat.c
+++ b/lib/libc/compat-43/sigcompat.c
@@ -59,7 +59,7 @@ sigvec(signo, sv, osv)
 	} else
 		sap = NULL;
 	osap = osv != NULL ? &osa : NULL;
-	ret = _sigaction(signo, sap, osap);
+	ret = __libc_sigaction(signo, sap, osap);
 	if (ret == 0 && osv != NULL) {
 		osv->sv_handler = osa.sa_handler;
 		osv->sv_flags = osa.sa_flags ^ SV_INTERRUPT;
@@ -77,7 +77,7 @@ sigsetmask(mask)
 
 	sigemptyset(&set);
 	set.__bits[0] = mask;
-	n = _sigprocmask(SIG_SETMASK, &set, &oset);
+	n = __libc_sigprocmask(SIG_SETMASK, &set, &oset);
 	if (n)
 		return (n);
 	return (oset.__bits[0]);
@@ -92,7 +92,7 @@ sigblock(mask)
 
 	sigemptyset(&set);
 	set.__bits[0] = mask;
-	n = _sigprocmask(SIG_BLOCK, &set, &oset);
+	n = __libc_sigprocmask(SIG_BLOCK, &set, &oset);
 	if (n)
 		return (n);
 	return (oset.__bits[0]);
@@ -105,7 +105,7 @@ sigpause(int mask)
 
 	sigemptyset(&set);
 	set.__bits[0] = mask;
-	return (_sigsuspend(&set));
+	return (__libc_sigsuspend(&set));
 }
 
 int
@@ -113,11 +113,11 @@ xsi_sigpause(int sig)
 {
 	sigset_t set;
 
-	if (_sigprocmask(SIG_BLOCK, NULL, &set) == -1)
+	if (__libc_sigprocmask(SIG_BLOCK, NULL, &set) == -1)
 		return (-1);
 	if (sigdelset(&set, sig) == -1)
 		return (-1);
-	return (_sigsuspend(&set));
+	return (__libc_sigsuspend(&set));
 }
 
 int
@@ -128,7 +128,7 @@ sighold(int sig)
 	sigemptyset(&set);
 	if (sigaddset(&set, sig) == -1)
 		return (-1);
-	return (_sigprocmask(SIG_BLOCK, &set, NULL));
+	return (__libc_sigprocmask(SIG_BLOCK, &set, NULL));
 }
 
 int
@@ -138,7 +138,7 @@ sigignore(int sig)
 
 	bzero(&sa, sizeof(sa));
 	sa.sa_handler = SIG_IGN;
-	return (_sigaction(sig, &sa, NULL));
+	return (__libc_sigaction(sig, &sa, NULL));
 }
 
 int
@@ -149,7 +149,7 @@ sigrelse(int sig)
 	sigemptyset(&set);
 	if (sigaddset(&set, sig) == -1)
 		return (-1);
-	return (_sigprocmask(SIG_UNBLOCK, &set, NULL));
+	return (__libc_sigprocmask(SIG_UNBLOCK, &set, NULL));
 }
 
 void
@@ -161,26 +161,26 @@ void
 	sigemptyset(&set);
 	if (sigaddset(&set, sig) == -1)
 		return (SIG_ERR);
-	if (_sigprocmask(SIG_BLOCK, NULL, &pset) == -1)
+	if (__libc_sigprocmask(SIG_BLOCK, NULL, &pset) == -1)
 		return (SIG_ERR);
 	if ((__sighandler_t *)disp == SIG_HOLD) {
-		if (_sigprocmask(SIG_BLOCK, &set, &pset) == -1)
+		if (__libc_sigprocmask(SIG_BLOCK, &set, &pset) == -1)
 			return (SIG_ERR);
 		if (sigismember(&pset, sig))
 			return (SIG_HOLD);
 		else {
-			if (_sigaction(sig, NULL, &psa) == -1)
+			if (__libc_sigaction(sig, NULL, &psa) == -1)
 				return (SIG_ERR);
 			return (psa.sa_handler);
 		}
 	} else {
-		if (_sigprocmask(SIG_UNBLOCK, &set, &pset) == -1)
+		if (__libc_sigprocmask(SIG_UNBLOCK, &set, &pset) == -1)
 			return (SIG_ERR);
 	}
 
 	bzero(&sa, sizeof(sa));
 	sa.sa_handler = disp;
-	if (_sigaction(sig, &sa, &psa) == -1)
+	if (__libc_sigaction(sig, &sa, &psa) == -1)
 		return (SIG_ERR);
 	if (sigismember(&pset, sig))
 		return (SIG_HOLD);
diff --git a/lib/libc/db/btree/bt_open.c b/lib/libc/db/btree/bt_open.c
index 94ba014..051fc28 100644
--- a/lib/libc/db/btree/bt_open.c
+++ b/lib/libc/db/btree/bt_open.c
@@ -57,6 +57,7 @@ __FBSDID("$FreeBSD$");
 #include <string.h>
 #include <unistd.h>
 #include "un-namespace.h"
+#include "libc_private.h"
 
 #include <db.h>
 #include "btree.h"
@@ -401,10 +402,10 @@ tmp(void)
 	}
 
 	(void)sigfillset(&set);
-	(void)_sigprocmask(SIG_BLOCK, &set, &oset);
+	(void)__libc_sigprocmask(SIG_BLOCK, &set, &oset);
 	if ((fd = mkostemp(path, O_CLOEXEC)) != -1)
 		(void)unlink(path);
-	(void)_sigprocmask(SIG_SETMASK, &oset, NULL);
+	(void)__libc_sigprocmask(SIG_SETMASK, &oset, NULL);
 	return(fd);
 }
 
diff --git a/lib/libc/db/hash/hash_page.c b/lib/libc/db/hash/hash_page.c
index d319d98..8040419 100644
--- a/lib/libc/db/hash/hash_page.c
+++ b/lib/libc/db/hash/hash_page.c
@@ -66,6 +66,7 @@ __FBSDID("$FreeBSD$");
 #include <assert.h>
 #endif
 #include "un-namespace.h"
+#include "libc_private.h"
 
 #include <db.h>
 #include "hash.h"
@@ -861,10 +862,10 @@ open_temp(HTAB *hashp)
 
 	/* Block signals; make sure file goes away at process exit. */
 	(void)sigfillset(&set);
-	(void)_sigprocmask(SIG_BLOCK, &set, &oset);
+	(void)__libc_sigprocmask(SIG_BLOCK, &set, &oset);
 	if ((hashp->fp = mkostemp(path, O_CLOEXEC)) != -1)
 		(void)unlink(path);
-	(void)_sigprocmask(SIG_SETMASK, &oset, (sigset_t *)NULL);
+	(void)__libc_sigprocmask(SIG_SETMASK, &oset, (sigset_t *)NULL);
 	return (hashp->fp != -1 ? 0 : -1);
 }
 
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;
diff --git a/lib/libc/gen/posix_spawn.c b/lib/libc/gen/posix_spawn.c
index e3124b2..673c760 100644
--- a/lib/libc/gen/posix_spawn.c
+++ b/lib/libc/gen/posix_spawn.c
@@ -118,15 +118,18 @@ process_spawnattr(const posix_spawnattr_t sa)
 			return (errno);
 	}
 
-	/* Set signal masks/defaults */
+	/*
+	 * Set signal masks/defaults.
+	 * Use unwrapped syscall, libthr is in undefined state after vfork().
+	 */
 	if (sa->sa_flags & POSIX_SPAWN_SETSIGMASK) {
-		_sigprocmask(SIG_SETMASK, &sa->sa_sigmask, NULL);
+		__libc_sigprocmask(SIG_SETMASK, &sa->sa_sigmask, NULL);
 	}
 
 	if (sa->sa_flags & POSIX_SPAWN_SETSIGDEF) {
 		for (i = 1; i <= _SIG_MAXSIG; i++) {
 			if (sigismember(&sa->sa_sigdefault, i))
-				if (_sigaction(i, &sigact, NULL) != 0)
+				if (__libc_sigaction(i, &sigact, NULL) != 0)
 					return (errno);
 		}
 	}
diff --git a/lib/libc/gen/readpassphrase.c b/lib/libc/gen/readpassphrase.c
index 95ae725..60051a1 100644
--- a/lib/libc/gen/readpassphrase.c
+++ b/lib/libc/gen/readpassphrase.c
@@ -36,6 +36,7 @@ __FBSDID("$FreeBSD$");
 #include <unistd.h>
 #include <readpassphrase.h>
 #include "un-namespace.h"
+#include "libc_private.h"
 
 static volatile sig_atomic_t signo[NSIG];
 
@@ -104,15 +105,15 @@ restart:
 	sigemptyset(&sa.sa_mask);
 	sa.sa_flags = 0;		/* don't restart system calls */
 	sa.sa_handler = handler;
-	(void)_sigaction(SIGALRM, &sa, &savealrm);
-	(void)_sigaction(SIGHUP, &sa, &savehup);
-	(void)_sigaction(SIGINT, &sa, &saveint);
-	(void)_sigaction(SIGPIPE, &sa, &savepipe);
-	(void)_sigaction(SIGQUIT, &sa, &savequit);
-	(void)_sigaction(SIGTERM, &sa, &saveterm);
-	(void)_sigaction(SIGTSTP, &sa, &savetstp);
-	(void)_sigaction(SIGTTIN, &sa, &savettin);
-	(void)_sigaction(SIGTTOU, &sa, &savettou);
+	(void)__libc_sigaction(SIGALRM, &sa, &savealrm);
+	(void)__libc_sigaction(SIGHUP, &sa, &savehup);
+	(void)__libc_sigaction(SIGINT, &sa, &saveint);
+	(void)__libc_sigaction(SIGPIPE, &sa, &savepipe);
+	(void)__libc_sigaction(SIGQUIT, &sa, &savequit);
+	(void)__libc_sigaction(SIGTERM, &sa, &saveterm);
+	(void)__libc_sigaction(SIGTSTP, &sa, &savetstp);
+	(void)__libc_sigaction(SIGTTIN, &sa, &savettin);
+	(void)__libc_sigaction(SIGTTOU, &sa, &savettou);
 
 	if (!(flags & RPP_STDIN))
 		(void)_write(output, prompt, strlen(prompt));
@@ -142,15 +143,15 @@ restart:
 		    errno == EINTR && !signo[SIGTTOU])
 			continue;
 	}
-	(void)_sigaction(SIGALRM, &savealrm, NULL);
-	(void)_sigaction(SIGHUP, &savehup, NULL);
-	(void)_sigaction(SIGINT, &saveint, NULL);
-	(void)_sigaction(SIGQUIT, &savequit, NULL);
-	(void)_sigaction(SIGPIPE, &savepipe, NULL);
-	(void)_sigaction(SIGTERM, &saveterm, NULL);
-	(void)_sigaction(SIGTSTP, &savetstp, NULL);
-	(void)_sigaction(SIGTTIN, &savettin, NULL);
-	(void)_sigaction(SIGTTOU, &savettou, NULL);
+	(void)__libc_sigaction(SIGALRM, &savealrm, NULL);
+	(void)__libc_sigaction(SIGHUP, &savehup, NULL);
+	(void)__libc_sigaction(SIGINT, &saveint, NULL);
+	(void)__libc_sigaction(SIGQUIT, &savequit, NULL);
+	(void)__libc_sigaction(SIGPIPE, &savepipe, NULL);
+	(void)__libc_sigaction(SIGTERM, &saveterm, NULL);
+	(void)__libc_sigaction(SIGTSTP, &savetstp, NULL);
+	(void)__libc_sigaction(SIGTTIN, &savettin, NULL);
+	(void)__libc_sigaction(SIGTTOU, &savettou, NULL);
 	if (input != STDIN_FILENO)
 		(void)_close(input);
 
diff --git a/lib/libc/gen/setmode.c b/lib/libc/gen/setmode.c
index 815cf14..7525567 100644
--- a/lib/libc/gen/setmode.c
+++ b/lib/libc/gen/setmode.c
@@ -53,6 +53,7 @@ __FBSDID("$FreeBSD$");
 #include <stdio.h>
 #endif
 #include "un-namespace.h"
+#include "libc_private.h"
 
 #define	SET_LEN	6		/* initial # of bitcmd struct to malloc */
 #define	SET_LEN_INCR 4		/* # of bitcmd structs to add as needed */
@@ -364,9 +365,9 @@ getumask(void)
 	 * handler, protect them as best we can.
 	 */
 	sigfillset(&sigset);
-	(void)_sigprocmask(SIG_BLOCK, &sigset, &sigoset);
+	(void)__libc_sigprocmask(SIG_BLOCK, &sigset, &sigoset);
 	(void)umask(mask = umask(0));
-	(void)_sigprocmask(SIG_SETMASK, &sigoset, NULL);
+	(void)__libc_sigprocmask(SIG_SETMASK, &sigoset, NULL);
 	return (mask);
 }
 
diff --git a/lib/libc/gen/siginterrupt.c b/lib/libc/gen/siginterrupt.c
index fde33ca..d99b772 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));
 }
diff --git a/lib/libc/gen/signal.c b/lib/libc/gen/signal.c
index ee96dcc..70e7f17 100644
--- a/lib/libc/gen/signal.c
+++ b/lib/libc/gen/signal.c
@@ -44,9 +44,7 @@ __FBSDID("$FreeBSD$");
 sigset_t _sigintr __hidden;	/* shared with siginterrupt */
 
 sig_t
-signal(s, a)
-	int s;
-	sig_t a;
+signal(int s, sig_t a)
 {
 	struct sigaction sa, osa;
 
@@ -55,7 +53,7 @@ signal(s, a)
 	sa.sa_flags = 0;
 	if (!sigismember(&_sigintr, s))
 		sa.sa_flags |= SA_RESTART;
-	if (_sigaction(s, &sa, &osa) < 0)
+	if (__libc_sigaction(s, &sa, &osa) < 0)
 		return (SIG_ERR);
 	return (osa.sa_handler);
 }
diff --git a/lib/libc/gen/wordexp.c b/lib/libc/gen/wordexp.c
index 958ddc6..859ca50 100644
--- a/lib/libc/gen/wordexp.c
+++ b/lib/libc/gen/wordexp.c
@@ -38,6 +38,7 @@
 #include <unistd.h>
 #include <wordexp.h>
 #include "un-namespace.h"
+#include "libc_private.h"
 
 __FBSDID("$FreeBSD$");
 
@@ -127,12 +128,12 @@ we_askshell(const char *words, wordexp_t *we, int flags)
 		return (WRDE_NOSPACE);	/* XXX */
 	(void)sigemptyset(&newsigblock);
 	(void)sigaddset(&newsigblock, SIGCHLD);
-	(void)_sigprocmask(SIG_BLOCK, &newsigblock, &oldsigblock);
+	(void)__libc_sigprocmask(SIG_BLOCK, &newsigblock, &oldsigblock);
 	if ((pid = fork()) < 0) {
 		serrno = errno;
 		_close(pdes[0]);
 		_close(pdes[1]);
-		(void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
+		(void)__libc_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
 		errno = serrno;
 		return (WRDE_NOSPACE);	/* XXX */
 	}
@@ -140,7 +141,7 @@ we_askshell(const char *words, wordexp_t *we, int flags)
 		/*
 		 * We are the child; make /bin/sh expand `words'.
 		 */
-		(void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
+		(void)__libc_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
 		if ((pdes[1] != STDOUT_FILENO ?
 		    _dup2(pdes[1], STDOUT_FILENO) :
 		    _fcntl(pdes[1], F_SETFD, 0)) < 0)
@@ -222,7 +223,7 @@ cleanup:
 	do
 		wpid = _waitpid(pid, &status, 0);
 	while (wpid < 0 && errno == EINTR);
-	(void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
+	(void)__libc_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
 	if (error != 0) {
 		errno = serrno;
 		return (error);
diff --git a/lib/libc/i386/gen/setjmp.S b/lib/libc/i386/gen/setjmp.S
index 6e15868..eb33e10 100644
--- a/lib/libc/i386/gen/setjmp.S
+++ b/lib/libc/i386/gen/setjmp.S
@@ -50,21 +50,12 @@ __FBSDID("$FreeBSD$");
 
 ENTRY(setjmp)
 	movl	4(%esp),%ecx
-	PIC_PROLOGUE
-#ifdef PIC
-	subl	$12,%esp		/* make the stack 16-byte aligned */
-#endif
 	leal	28(%ecx), %eax
 	pushl	%eax			/* (sigset_t*)oset */
 	pushl	$0			/* (sigset_t*)set  */
 	pushl	$1			/* SIG_BLOCK       */
-	call	PIC_PLT(CNAME(_sigprocmask))
-#ifdef PIC
-	addl	$24,%esp
-#else
+	call	__libc_sigprocmask
 	addl	$12,%esp
-#endif
-	PIC_EPILOGUE
 	movl	4(%esp),%ecx
 	movl	0(%esp),%edx
 	movl	%edx, 0(%ecx)
@@ -81,21 +72,12 @@ END(setjmp)
 	WEAK_REFERENCE(__longjmp, longjmp)
 ENTRY(__longjmp)
 	movl	4(%esp),%edx
-	PIC_PROLOGUE
-#ifdef PIC
-	subl	$12,%esp		/* make the stack 16-byte aligned */
-#endif
 	pushl	$0			/* (sigset_t*)oset */
 	leal	28(%edx), %eax
 	pushl	%eax			/* (sigset_t*)set  */
 	pushl	$3			/* SIG_SETMASK     */
-	call	PIC_PLT(CNAME(_sigprocmask))
-#ifdef PIC
-	addl	$24,%esp
-#else
+	call	__libc_sigprocmask
 	addl	$12,%esp
-#endif
-	PIC_EPILOGUE
 	movl	4(%esp),%edx
 	movl	8(%esp),%eax
 	movl	0(%edx),%ecx
diff --git a/lib/libc/i386/gen/sigsetjmp.S b/lib/libc/i386/gen/sigsetjmp.S
index 1c63649..7566d72 100644
--- a/lib/libc/i386/gen/sigsetjmp.S
+++ b/lib/libc/i386/gen/sigsetjmp.S
@@ -59,21 +59,12 @@ ENTRY(sigsetjmp)
 	movl	%eax,44(%ecx)
 	testl	%eax,%eax
 	jz	2f
-	PIC_PROLOGUE
-#ifdef PIC
-	subl	$12,%esp		/* make the stack 16-byte aligned */
-#endif
 	leal	28(%ecx), %eax
 	pushl	%eax			/* (sigset_t*)oset */
 	pushl	$0			/* (sigset_t*)set  */
 	pushl	$1			/* SIG_BLOCK       */
-	call	PIC_PLT(CNAME(_sigprocmask))
-#ifdef PIC
-	addl	$24,%esp
-#else
+	call	__libc_sigprocmask
 	addl	$12,%esp
-#endif
-	PIC_EPILOGUE
 	movl	4(%esp),%ecx
 2:	movl	0(%esp),%edx
 	movl	%edx, 0(%ecx)
@@ -92,21 +83,12 @@ ENTRY(__siglongjmp)
 	movl	4(%esp),%edx
 	cmpl	$0,44(%edx)
 	jz	2f
-	PIC_PROLOGUE
-#ifdef PIC
-	subl	$12,%esp		/* make the stack 16-byte aligned */
-#endif
 	pushl	$0			/* (sigset_t*)oset */
 	leal	28(%edx), %eax
 	pushl	%eax			/* (sigset_t*)set  */
 	pushl	$3			/* SIG_SETMASK     */
-	call	PIC_PLT(CNAME(_sigprocmask))
-#ifdef PIC
-	addl	$24,%esp
-#else
+	call	__libc_sigprocmask
 	addl	$12,%esp
-#endif
-	PIC_EPILOGUE
 	movl	4(%esp),%edx
 2:	movl	8(%esp),%eax
 	movl	0(%edx),%ecx
diff --git a/lib/libc/include/libc_private.h b/lib/libc/include/libc_private.h
index a670d63..5caf9a3 100644
--- a/lib/libc/include/libc_private.h
+++ b/lib/libc/include/libc_private.h
@@ -359,6 +359,11 @@ __pid_t		__sys_wait6(enum idtype, __id_t, int *, int,
 __ssize_t	__sys_write(int, const void *, __size_t);
 __ssize_t	__sys_writev(int, const struct iovec *, int);
 
+int		__libc_sigaction(int, const struct sigaction *,
+		    struct sigaction *) __hidden;
+int		__libc_sigprocmask(int, const __sigset_t *, __sigset_t *)
+		    __hidden;
+int		__libc_sigsuspend(const __sigset_t *) __hidden;
 int		__libc_sigwait(const __sigset_t * __restrict,
 		    int * restrict sig);
 int		__libc_system(const char *);
diff --git a/lib/libc/net/rcmd.c b/lib/libc/net/rcmd.c
index 2885dc3..1ba9888 100644
--- a/lib/libc/net/rcmd.c
+++ b/lib/libc/net/rcmd.c
@@ -58,6 +58,7 @@ __FBSDID("$FreeBSD$");
 #endif
 #include <arpa/nameser.h>
 #include "un-namespace.h"
+#include "libc_private.h"
 
 extern int innetgr( const char *, const char *, const char *, const char * );
 
@@ -148,7 +149,7 @@ rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, af)
 	refused = 0;
 	sigemptyset(&newmask);
 	sigaddset(&newmask, SIGURG);
-	_sigprocmask(SIG_BLOCK, (const sigset_t *)&newmask, &oldmask);
+	__libc_sigprocmask(SIG_BLOCK, (const sigset_t *)&newmask, &oldmask);
 	for (timo = 1, lport = IPPORT_RESERVED - 1;;) {
 		s = rresvport_af(&lport, ai->ai_family);
 		if (s < 0) {
@@ -163,7 +164,7 @@ rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, af)
 				(void)fprintf(stderr, "rcmd: socket: %s\n",
 				    strerror(errno));
 			freeaddrinfo(res);
-			_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask,
+			__libc_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask,
 			    NULL);
 			return (-1);
 		}
@@ -181,7 +182,7 @@ rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, af)
 			(void)fprintf(stderr, "%s: %s\n",
 				      *ahost, strerror(errno));
 			freeaddrinfo(res);
-			_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask,
+			__libc_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask,
 			    NULL);
 			return (-1);
 		}
@@ -306,7 +307,7 @@ again:
 		}
 		goto bad2;
 	}
-	_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask, NULL);
+	__libc_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask, NULL);
 	freeaddrinfo(res);
 	return (s);
 bad2:
@@ -314,7 +315,7 @@ bad2:
 		(void)_close(*fd2p);
 bad:
 	(void)_close(s);
-	_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask, NULL);
+	__libc_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask, NULL);
 	freeaddrinfo(res);
 	return (-1);
 }
diff --git a/lib/libc/stdio/tmpfile.c b/lib/libc/stdio/tmpfile.c
index c67d1e4..e5a2be1 100644
--- a/lib/libc/stdio/tmpfile.c
+++ b/lib/libc/stdio/tmpfile.c
@@ -46,9 +46,10 @@ __FBSDID("$FreeBSD$");
 #include <string.h>
 #include <paths.h>
 #include "un-namespace.h"
+#include "libc_private.h"
 
 FILE *
-tmpfile()
+tmpfile(void)
 {
 	sigset_t set, oset;
 	FILE *fp;
@@ -69,7 +70,7 @@ tmpfile()
 		return (NULL);
 
 	sigfillset(&set);
-	(void)_sigprocmask(SIG_BLOCK, &set, &oset);
+	(void)__libc_sigprocmask(SIG_BLOCK, &set, &oset);
 
 	fd = mkstemp(buf);
 	if (fd != -1)
@@ -77,7 +78,7 @@ tmpfile()
 
 	free(buf);
 
-	(void)_sigprocmask(SIG_SETMASK, &oset, NULL);
+	(void)__libc_sigprocmask(SIG_SETMASK, &oset, NULL);
 
 	if (fd == -1)
 		return (NULL);
diff --git a/lib/libc/stdlib/abort.c b/lib/libc/stdlib/abort.c
index b137e49..022c6aa 100644
--- a/lib/libc/stdlib/abort.c
+++ b/lib/libc/stdlib/abort.c
@@ -61,7 +61,7 @@ abort()
 	 * any errors -- ISO C doesn't allow abort to return anyway.
 	 */
 	sigdelset(&act.sa_mask, SIGABRT);
-	(void)_sigprocmask(SIG_SETMASK, &act.sa_mask, NULL);
+	(void)__libc_sigprocmask(SIG_SETMASK, &act.sa_mask, NULL);
 	(void)raise(SIGABRT);
 
 	/*
@@ -71,9 +71,9 @@ abort()
 	act.sa_handler = SIG_DFL;
 	act.sa_flags = 0;
 	sigfillset(&act.sa_mask);
-	(void)_sigaction(SIGABRT, &act, NULL);
+	(void)__libc_sigaction(SIGABRT, &act, NULL);
 	sigdelset(&act.sa_mask, SIGABRT);
-	(void)_sigprocmask(SIG_SETMASK, &act.sa_mask, NULL);
+	(void)__libc_sigprocmask(SIG_SETMASK, &act.sa_mask, NULL);
 	(void)raise(SIGABRT);
 	exit(1);
 }
diff --git a/lib/libc/stdlib/system.c b/lib/libc/stdlib/system.c
index bd9ea5a..2b298e4 100644
--- a/lib/libc/stdlib/system.c
+++ b/lib/libc/stdlib/system.c
@@ -70,16 +70,20 @@ __libc_system(const char *command)
 	(void)sigaddset(&newsigblock, SIGCHLD);
 	(void)sigaddset(&newsigblock, SIGINT);
 	(void)sigaddset(&newsigblock, SIGQUIT);
-	(void)_sigprocmask(SIG_BLOCK, &newsigblock, &oldsigblock);
+	(void)__libc_sigprocmask(SIG_BLOCK, &newsigblock, &oldsigblock);
 	switch(pid = vfork()) {
+	/*
+	 * In the child, use unwrapped syscalls.  libthr is in
+	 * undefined state after vfork().
+	 */
 	case -1:			/* error */
-		(void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
+		(void)__libc_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
 		return (-1);
 	case 0:				/* child */
 		/*
 		 * Restore original signal dispositions and exec the command.
 		 */
-		(void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
+		(void)__sys_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
 		execl(_PATH_BSHELL, "sh", "-c", command, (char *)NULL);
 		_exit(127);
 	}
@@ -92,16 +96,16 @@ __libc_system(const char *command)
 	memset(&ign, 0, sizeof(ign));
 	ign.sa_handler = SIG_IGN;
 	(void)sigemptyset(&ign.sa_mask);
-	(void)_sigaction(SIGINT, &ign, &intact);
-	(void)_sigaction(SIGQUIT, &ign, &quitact);
+	(void)__libc_sigaction(SIGINT, &ign, &intact);
+	(void)__libc_sigaction(SIGQUIT, &ign, &quitact);
 	savedpid = pid;
 	do {
 		pid = _wait4(savedpid, &pstat, 0, (struct rusage *)0);
 	} while (pid == -1 && errno == EINTR);
-	(void)_sigaction(SIGINT, &intact, NULL);
-	(void)_sigaction(SIGQUIT,  &quitact, NULL);
-	(void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
-	return(pid == -1 ? -1 : pstat);
+	(void)__libc_sigaction(SIGINT, &intact, NULL);
+	(void)__libc_sigaction(SIGQUIT,  &quitact, NULL);
+	(void)__libc_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
+	return (pid == -1 ? -1 : pstat);
 }
 
 __weak_reference(__libc_system, __system);
diff --git a/lib/libc/sys/sigaction.c b/lib/libc/sys/sigaction.c
index 7645538..b4d6563 100644
--- a/lib/libc/sys/sigaction.c
+++ b/lib/libc/sys/sigaction.c
@@ -38,6 +38,7 @@ __FBSDID("$FreeBSD$");
 #include "libc_private.h"
 
 __weak_reference(__sys_sigaction, __sigaction);
+__weak_reference(sigaction, __libc_sigaction);
 
 #pragma weak sigaction
 int
diff --git a/lib/libc/sys/sigprocmask.c b/lib/libc/sys/sigprocmask.c
index 40dba95..d24bb89 100644
--- a/lib/libc/sys/sigprocmask.c
+++ b/lib/libc/sys/sigprocmask.c
@@ -38,6 +38,7 @@ __FBSDID("$FreeBSD$");
 #include "libc_private.h"
 
 __weak_reference(__sys_sigprocmask, __sigprocmask);
+__weak_reference(sigprocmask, __libc_sigprocmask);
 
 #pragma weak sigprocmask
 int
diff --git a/lib/libc/sys/sigsuspend.c b/lib/libc/sys/sigsuspend.c
index 6e47368..1f980a1 100644
--- a/lib/libc/sys/sigsuspend.c
+++ b/lib/libc/sys/sigsuspend.c
@@ -38,6 +38,7 @@ __FBSDID("$FreeBSD$");
 #include "libc_private.h"
 
 __weak_reference(__sys_sigsuspend, __sigsuspend);
+__weak_reference(sigsuspend, __libc_sigsuspend);
 
 #pragma weak sigsuspend
 int