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, 31 insertions, 0 deletions

diff --git a/lib/libc/sys/w_sendmsg.c b/lib/libc/sys/w_sendmsg.c
new file mode 100644
index 00000000000..d184a212e59
--- /dev/null
+++ b/lib/libc/sys/w_sendmsg.c
@@ -0,0 +1,31 @@
+/*	$OpenBSD: w_sendmsg.c,v 1.1 2016/05/07 19:05:22 guenther Exp $ */
+/*
+ * Copyright (c) 2015 Philip Guenther <guenther@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/socket.h>
+#include "cancel.h"
+
+ssize_t
+sendmsg(int s, const struct msghdr *msg, int flags)
+{
+	ssize_t ret;
+
+	ENTER_CANCEL_POINT(1);
+	ret = HIDDEN(sendmsg)(s, msg, flags);
+	LEAVE_CANCEL_POINT(ret <= 0);
+	return (ret);
+}
+DEF_CANCEL(sendmsg);