Fix known issues which blow up the process after dlopen("libthr.so")

(or loading a dso linked to libthr.so into process which was not
linked against threading library).

MFC r276630:
Remove interposing, fix malloc, reinstall signal handlers wrappers on
libthr load.

MFC r276681:
Avoid calling internal libc function through PLT or accessing data
though GOT.

MFC r277032:
Reduce the size of the interposing table and amount of
cancellation-handling code in the libthr.

MFC note:
r276646 ("do not erronously export 'openat' symbol from rtld") is not
applicable to stable/10 yet, since PATHFDS support was not merged.

1 files changed, 84 insertions, 0 deletions

diff --git a/lib/libc/sys/interposing_table.c b/lib/libc/sys/interposing_table.c
new file mode 100644
index 0000000..d303779
--- /dev/null
+++ b/lib/libc/sys/interposing_table.c
@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2014 The FreeBSD Foundation.
+ * All rights reserved.
+ *
+ * Portions of this software were developed by Konstantin Belousov
+ * under sponsorship from the FreeBSD Foundation.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice(s), this list of conditions and the following disclaimer as
+ *    the first lines of this file unmodified other than the possible
+ *    addition of one or more copyright notices.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice(s), this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/types.h>
+#include "libc_private.h"
+
+#define	SLOT(a, b) \
+	[INTERPOS_##a] = (interpos_func_t)b
+interpos_func_t __libc_interposing[INTERPOS_MAX] = {
+	SLOT(accept, __sys_accept),
+	SLOT(accept4, __sys_accept4),
+	SLOT(aio_suspend, __sys_aio_suspend),
+	SLOT(close, __sys_close),
+	SLOT(connect, __sys_connect),
+	SLOT(fcntl, __fcntl_compat),
+	SLOT(fsync, __sys_fsync),
+	SLOT(fork, __sys_fork),
+	SLOT(msync, __sys_msync),
+	SLOT(nanosleep, __sys_nanosleep),
+	SLOT(openat, __sys_openat),
+	SLOT(poll, __sys_poll),
+	SLOT(pselect, __sys_pselect),
+	SLOT(read, __sys_read),
+	SLOT(readv, __sys_readv),
+	SLOT(recvfrom, __sys_recvfrom),
+	SLOT(recvmsg, __sys_recvmsg),
+	SLOT(select, __sys_select),
+	SLOT(sendmsg, __sys_sendmsg),
+	SLOT(sendto, __sys_sendto),
+	SLOT(setcontext, __sys_setcontext),
+	SLOT(sigaction, __sys_sigaction),
+	SLOT(sigprocmask, __sys_sigprocmask),
+	SLOT(sigsuspend, __sys_sigsuspend),
+	SLOT(sigwait, __libc_sigwait),
+	SLOT(sigtimedwait, __sys_sigtimedwait),
+	SLOT(sigwaitinfo, __sys_sigwaitinfo),
+	SLOT(swapcontext, __sys_swapcontext),
+	SLOT(system, __libc_system),
+	SLOT(tcdrain, __libc_tcdrain),
+	SLOT(wait4, __sys_wait4),
+	SLOT(write, __sys_write),
+	SLOT(writev, __sys_writev),
+	SLOT(_pthread_mutex_init_calloc_cb, _pthread_mutex_init_calloc_cb_stub),
+};
+#undef SLOT
+
+interpos_func_t *
+__libc_interposing_slot(int interposno)
+{
+
+	return (&__libc_interposing[interposno]);
+}