Use a Thread Information Block in both single and multi-threaded programs.

This stores errno, the cancelation flags, and related bits for each thread
and is allocated by ld.so or libc.a.  This is an ABI break from 5.9-stable!

Make libpthread dlopen'able by moving the cancelation wrappers into libc
and doing locking and fork/errno handling via callbacks that libpthread
registers when it first initializes.  'errno' *must* be declared via
<errno.h> now!

Clean up libpthread's symbol exports like libc.

On powerpc, offset the TIB/TCB/TLS data from the register per the ELF spec.

Testing by various, particularly sthen@ and patrick@
ok kettenis@

1 files changed, 19 insertions, 7 deletions

diff --git a/lib/libc/sys/w_fork.c b/lib/libc/sys/w_fork.c
index 89415491f82..668731fdf67 100644
--- a/lib/libc/sys/w_fork.c
+++ b/lib/libc/sys/w_fork.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: w_fork.c,v 1.2 2015/10/25 18:03:17 guenther Exp $ */
+/*	$OpenBSD: w_fork.c,v 1.3 2016/05/07 19:05:22 guenther Exp $ */
 
 /*
  * Copyright (c) 2008 Kurt Miller <kurt@openbsd.org>
@@ -30,14 +30,13 @@
  * $FreeBSD: /repoman/r/ncvs/src/lib/libc_r/uthread/uthread_atfork.c,v 1.1 2004/12/10 03:36:45 grog Exp $
  */
 
+#include <tib.h>
 #include <unistd.h>
 #include "thread_private.h"
 #include "atfork.h"
 
-pid_t	_thread_fork(void);
-
 pid_t
-fork(void)
+WRAP(fork)(void)
 {
 	struct atfork_fn *p;
 	pid_t newid;
@@ -46,15 +45,27 @@ fork(void)
 	 * In the common case the list is empty; remain async-signal-safe
 	 * then by skipping the locking and just forking
 	 */
-	if (TAILQ_FIRST(&_atfork_list) == NULL)
-		return (_thread_fork());
+	if (TAILQ_FIRST(&_atfork_list) == NULL) {
+		if (_thread_cb.tc_fork != NULL)
+			return _thread_cb.tc_fork();
+		newid = fork();
+		if (newid == 0)
+			TIB_GET()->tib_tid = getthrid();
+		return newid;
+	}
 
 	_ATFORK_LOCK();
 	TAILQ_FOREACH_REVERSE(p, &_atfork_list, atfork_listhead, fn_next)
 		if (p->fn_prepare)
 			p->fn_prepare();
 
-	newid = _thread_fork();
+	if (_thread_cb.tc_fork != NULL)
+		newid = _thread_cb.tc_fork();
+	else {
+		newid = fork();
+		if (newid == 0)
+			TIB_GET()->tib_tid = getthrid();
+	}
 
 	if (newid == 0) {
 		TAILQ_FOREACH(p, &_atfork_list, fn_next)
@@ -69,3 +80,4 @@ fork(void)
 
 	return (newid);
 }
+DEF_WRAP(fork);