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, 6 insertions, 2 deletions

diff --git a/lib/libc/gen/sleep.c b/lib/libc/gen/sleep.c
index b807c2d..6bb4ecd 100644
--- a/lib/libc/gen/sleep.c
+++ b/lib/libc/gen/sleep.c
@@ -40,6 +40,8 @@ __FBSDID("$FreeBSD$");
 #include <unistd.h>
 #include "un-namespace.h"
 
+#include "libc_private.h"
+
 unsigned int
 __sleep(unsigned int seconds)
 {
@@ -55,12 +57,14 @@ __sleep(unsigned int seconds)
 
 	time_to_sleep.tv_sec = seconds;
 	time_to_sleep.tv_nsec = 0;
-	if (_nanosleep(&time_to_sleep, &time_remaining) != -1)
+	if (((int (*)(const struct timespec *, struct timespec *))
+	    __libc_interposing[INTERPOS_nanosleep])(
+	    &time_to_sleep, &time_remaining) != -1)
 		return (0);
 	if (errno != EINTR)
 		return (seconds);		/* best guess */
 	return (time_remaining.tv_sec +
-		(time_remaining.tv_nsec != 0)); /* round up */
+	    (time_remaining.tv_nsec != 0)); /* round up */
 }
 
 __weak_reference(__sleep, sleep);