From 226946afd0440d73f9f8dcf4d800cd02a8a31093 Mon Sep 17 00:00:00 2001
From: zrj <rimvydas.jasinskas@gmail.com>
Date: Tue, 4 Oct 2016 10:37:35 +0300
Subject: [PATCH 08/20] libc: Rip out pthread_cancel stub symbol.

After looking through use cases i couldn't find any signs of libc
needing to provide stub for pthread_cancel() function.
It doesn't make much sense for any program to use this symbol but
not use the pthread_create(). With this assumption it should be safe
to move out pthread_cancel() from libc to libpthread.so dummy to be
together with weak symbol of pthread_create().

Doing just that fixes how gcc libs check for pthread presence when
playing weak symbol chasing games. I don't judge but configure.ac?
---
 lib/libc/gen/Symbol.map       |  1 -
 lib/libc/gen/_pthread_stubs.c |  4 +++-
 lib/libpthread/dummy.c        | 11 +++++++++--
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/lib/libc/gen/Symbol.map b/lib/libc/gen/Symbol.map
index 8e94912..253222e 100644
--- a/lib/libc/gen/Symbol.map
+++ b/lib/libc/gen/Symbol.map
@@ -53,7 +53,6 @@ DF404.0 {
     pthread_barrierattr_getpshared;
     pthread_barrierattr_init;
     pthread_barrierattr_setpshared;
-    pthread_cancel;
     pthread_cleanup_pop;
     pthread_cleanup_push;
     pthread_cond_broadcast;
diff --git a/lib/libc/gen/_pthread_stubs.c b/lib/libc/gen/_pthread_stubs.c
index 31cf5b6..9cbb1ab 100644
--- a/lib/libc/gen/_pthread_stubs.c
+++ b/lib/libc/gen/_pthread_stubs.c
@@ -39,6 +39,8 @@
  * latter can't be allowed to exit/terminate).
  */
 
+#define WRlc(f, n)			\
+    __weak_reference(f, _ ## n);
 #define WR(f, n)			\
     __weak_reference(f, _ ## n);	\
     __weak_reference(f, n)
@@ -73,7 +75,7 @@ WR(stub_zero, pthread_barrierattr_destroy);
 WR(stub_zero, pthread_barrierattr_getpshared);
 WR(stub_zero, pthread_barrierattr_init);
 WR(stub_zero, pthread_barrierattr_setpshared);
-WR(stub_zero, pthread_cancel);
+WRlc(stub_zero, pthread_cancel);
 WR(stub_zero, pthread_cleanup_pop);
 WR(stub_zero, pthread_cleanup_push);
 WR(stub_zero, pthread_cond_broadcast);
diff --git a/lib/libpthread/dummy.c b/lib/libpthread/dummy.c
index 9f9d8bd..54c7076 100644
--- a/lib/libpthread/dummy.c
+++ b/lib/libpthread/dummy.c
@@ -1,5 +1,3 @@
-/* $DragonFly: src/lib/libpthread/dummy.c,v 1.1 2007/04/17 12:34:07 corecode Exp $ */
-
 #include <stdio.h>
 #include <stdlib.h>
 
@@ -11,3 +9,12 @@ dummy_pthread_create(void)
 }
 
 __weak_reference(dummy_pthread_create, pthread_create);
+
+static void __attribute__((__used__))
+dummy_pthread_cancel(void)
+{
+	fprintf(stderr, "libpthread.so: dummy weak symbol executed\n");
+	abort();
+}
+
+__weak_reference(dummy_pthread_cancel, pthread_cancel);
-- 
2.9.2