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, 42 insertions, 0 deletions

diff --git a/lib/libc/thread/callbacks.c b/lib/libc/thread/callbacks.c
new file mode 100644
index 00000000000..c57a931b08c
--- /dev/null
+++ b/lib/libc/thread/callbacks.c
@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2014 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 <stdio.h>
+#include <signal.h>
+#include <string.h>
+#include <unistd.h>
+#include "thread_private.h"
+
+void
+_thread_set_callbacks(const struct thread_callbacks *cb, size_t len)
+{
+	sigset_t allmask, omask;
+
+	if (sizeof(*cb) != len) {
+		fprintf(stderr, "library mismatch: libc expected %z but"
+		    " libpthread gave %z\n", sizeof(*cb), len);
+		fflush(stderr);
+		_exit(44);
+	}
+
+	sigfillset(&allmask);
+	if (sigprocmask(SIG_BLOCK, &allmask, &omask) == 0) {
+		/* mprotect RW */
+		memcpy(&_thread_cb, cb, sizeof(_thread_cb));
+		/* mprotect RO | LOCKPERM | NOUNMAP */
+		sigprocmask(SIG_SETMASK, &omask, NULL);
+	}
+}