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, 8 insertions, 5 deletions

diff --git a/lib/libc/gen/wait3.c b/lib/libc/gen/wait3.c
index 6098773..965effe 100644
--- a/lib/libc/gen/wait3.c
+++ b/lib/libc/gen/wait3.c
@@ -40,11 +40,14 @@ __FBSDID("$FreeBSD$");
 #include <sys/resource.h>
 #include "un-namespace.h"
 
+#include "libc_private.h"
+
 pid_t
-wait3(istat, options, rup)
-	int *istat;
-	int options;
-	struct rusage *rup;
+__wait3(int *istat, int options, struct rusage *rup)
 {
-	return (_wait4(WAIT_ANY, istat, options, rup));
+
+	return (((pid_t (*)(pid_t, int *, int, struct rusage *))
+	    __libc_interposing[INTERPOS_wait4])(WAIT_ANY, istat, options, rup));
 }
+
+__weak_reference(__wait3, wait3);