contrib: Add upstream patch to make libbluray pthread recursive mutexes portable.

1 files changed, 114 insertions, 0 deletions

diff --git a/contrib/libbluray/A00-pthread-mutex.patch b/contrib/libbluray/A00-pthread-mutex.patch
new file mode 100644
index 000000000..5718f25c7
--- /dev/null
+++ b/contrib/libbluray/A00-pthread-mutex.patch
@@ -0,0 +1,114 @@
+From bc2d0d8c41541bfea6fc2974bb4722c096211d9e Mon Sep 17 00:00:00 2001
+From: Kamil Rytarowski <[email protected]>
+Date: Thu, 13 Feb 2020 16:23:21 +0100
+Subject: [PATCH] mutex: Switch the POSIX backend to PTHREAD_MUTEX_RECURSIVE
+
+The code for recursive mutexes triggered Undefined Behavior
+and crash as pthread_equal(3) was not used in a portable way.
+On the first call of mutex_lock() pthread_equal() was called with
+a pthread_t of value -1 which is invalid.
+
+Passing a non valid thread ID to pthread_equal is undefined.
+
+Switch the backend to native interface for POSIX recursive
+mutexes with PTHREAD_MUTEX_RECURSIVE and simplify the code.
+
+Detected on NetBSD/amd64 9.99.46.
+
+Signed-off-by: Marvin Scholz <[email protected]>
+---
+ src/util/mutex.c | 47 +++++++++--------------------------------------
+ 1 file changed, 9 insertions(+), 38 deletions(-)
+
+diff --git a/src/util/mutex.c b/src/util/mutex.c
+index c32bb5fd..b3fee526 100644
+--- a/src/util/mutex.c
++++ b/src/util/mutex.c
+@@ -68,18 +68,16 @@ static int _mutex_destroy(MUTEX_IMPL *p)
+ 
+ #elif defined(HAVE_PTHREAD_H)
+ 
+-typedef struct {
+-    int             lock_count;
+-    pthread_t       owner;
+-    pthread_mutex_t mutex;
+-} MUTEX_IMPL;
++typedef pthread_mutex_t MUTEX_IMPL;
+ 
+ static int _mutex_init(MUTEX_IMPL *p)
+ {
+-    p->owner      = (pthread_t)-1;
+-    p->lock_count = 0;
++    pthread_mutexattr_t attr;
+ 
+-    if (pthread_mutex_init(&p->mutex, NULL)) {
++    pthread_mutexattr_init(&attr);
++    pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
++
++    if (pthread_mutex_init(p, &attr)) {
+         BD_DEBUG(DBG_BLURAY|DBG_CRIT, "pthread_mutex_init() failed !\n");
+         return -1;
+     }
+@@ -89,40 +87,17 @@ static int _mutex_init(MUTEX_IMPL *p)
+ 
+ static int _mutex_lock(MUTEX_IMPL *p)
+ {
+-    if (pthread_equal(p->owner, pthread_self())) {
+-        /* recursive lock */
+-        p->lock_count++;
+-        return 0;
+-    }
+-
+-    if (pthread_mutex_lock(&p->mutex)) {
++    if (pthread_mutex_lock(p)) {
+         BD_DEBUG(DBG_BLURAY|DBG_CRIT, "pthread_mutex_lock() failed !\n");
+         return -1;
+     }
+ 
+-    p->owner      = pthread_self();
+-    p->lock_count = 1;
+-
+     return 0;
+ }
+ 
+ static int _mutex_unlock(MUTEX_IMPL *p)
+ {
+-    if (!pthread_equal(p->owner, pthread_self())) {
+-        BD_DEBUG(DBG_BLURAY|DBG_CRIT, "bd_mutex_unlock(): not owner !\n");
+-        return -1;
+-    }
+-
+-    p->lock_count--;
+-    if (p->lock_count > 0) {
+-        return 0;
+-    }
+-
+-    /* unlock */
+-
+-    p->owner = (pthread_t)-1;
+-
+-    if (pthread_mutex_unlock(&p->mutex)) {
++    if (pthread_mutex_unlock(p)) {
+         BD_DEBUG(DBG_BLURAY|DBG_CRIT, "pthread_mutex_unlock() failed !\n");
+         return -1;
+     }
+@@ -132,10 +107,7 @@ static int _mutex_unlock(MUTEX_IMPL *p)
+ 
+ static int _mutex_destroy(MUTEX_IMPL *p)
+ {
+-    _mutex_lock(p);
+-    _mutex_unlock(p);
+-
+-    if (pthread_mutex_destroy(&p->mutex)) {
++    if (pthread_mutex_destroy(p)) {
+         BD_DEBUG(DBG_BLURAY|DBG_CRIT, "pthread_mutex_destroy() failed !\n");
+         return -1;
+     }
+@@ -193,4 +165,3 @@ int bd_mutex_destroy(BD_MUTEX *p)
+     X_FREE(p->impl);
+     return 0;
+ }
+-
+-- 
+2.24.1
+