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, 11 insertions, 3 deletions

diff --git a/lib/libc/sys/sigwait.c b/lib/libc/sys/sigwait.c
index 2fdffdd..b21cabd 100644
--- a/lib/libc/sys/sigwait.c
+++ b/lib/libc/sys/sigwait.c
@@ -28,13 +28,21 @@ __FBSDID("$FreeBSD$");
 
 #include <errno.h>
 #include <signal.h>
+#include "libc_private.h"
 
-int __sys_sigwait(const sigset_t * restrict, int * restrict);
+__weak_reference(__libc_sigwait, __sigwait);
 
-__weak_reference(__sigwait, sigwait);
+#pragma weak sigwait
+int
+sigwait(const sigset_t *set, int *sig)
+{
+
+	return (((int (*)(const sigset_t *, int *))
+	    __libc_interposing[INTERPOS_sigwait])(set, sig));
+}
 
 int
-__sigwait(const sigset_t * restrict set, int * restrict sig)
+__libc_sigwait(const sigset_t *set, int *sig)
 {
 	int ret;