X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fruntime%2Fpthread-lutex.c;h=636521403598b1ab534ce9064383c38afb140bd0;hb=1439811447104b32d986bab40d6e2ed431247004;hp=285891b6595f0283a4218ac917f5965c12a2a5e6;hpb=402958f92506b9d3de852601b8c1ccb99b5ee558;p=sbcl.git

diff --git a/src/runtime/pthread-lutex.c b/src/runtime/pthread-lutex.c
index 285891b..6365214 100644
--- a/src/runtime/pthread-lutex.c
+++ b/src/runtime/pthread-lutex.c
@@ -15,17 +15,18 @@
 
 #if defined(LISP_FEATURE_SB_THREAD) && defined(LISP_FEATURE_SB_LUTEX)
 
+#include <errno.h>
 #include <stdlib.h>
 
 #include "runtime.h"
 #include "arch.h"
 #include "target-arch-os.h"
 #include "os.h"
+#include "pthread-lutex.h"
+#include "gencgc.h"
 
 #include "genesis/lutex.h"
 
-typedef unsigned long tagged_lutex_t;
-
 #if 1
 # define lutex_assert(ex)                                              \
 do {                                                                   \
@@ -55,10 +56,25 @@ lutex_init (tagged_lutex_t tagged_lutex)
     int ret;
     struct lutex *lutex = (struct lutex*) native_pointer(tagged_lutex);
 
+    lutex->mutexattr = malloc(sizeof(pthread_mutexattr_t));
+    lutex_assert(lutex->mutexattr != 0);
+
+    ret = pthread_mutexattr_init(lutex->mutexattr);
+    lutex_assert(ret == 0);
+
+    /* The default type of mutex is implementation dependent.
+     * We use PTHREAD_MUTEX_ERRORCHECK so that locking on mutexes
+     * locked by the same thread does not cause deadlocks. */
+    /* FIXME: pthread_mutexattr_settype is available on SUSv2 level
+     * implementations.  Can be used without checking? */
+    ret = pthread_mutexattr_settype(lutex->mutexattr,
+                                    PTHREAD_MUTEX_ERRORCHECK);
+    lutex_assert(ret == 0);
+
     lutex->mutex = malloc(sizeof(pthread_mutex_t));
     lutex_assert(lutex->mutex != 0);
 
-    ret = pthread_mutex_init(lutex->mutex, NULL);
+    ret = pthread_mutex_init(lutex->mutex, lutex->mutexattr);
     lutex_assert(ret == 0);
 
     lutex->condition_variable = malloc(sizeof(pthread_cond_t));
@@ -122,6 +138,28 @@ lutex_lock (tagged_lutex_t tagged_lutex)
     struct lutex *lutex = (struct lutex*) native_pointer(tagged_lutex);
 
     ret = thread_mutex_lock(lutex->mutex);
+    /* The mutex is locked by the same thread.
+     *
+     * FIXME: Usually when POSIX says that "an error value is returned"
+     * it actually refers to errno...
+     */
+    if (ret == EDEADLK)
+        return ret;
+    lutex_assert(ret == 0);
+
+    return ret;
+}
+
+int
+lutex_trylock (tagged_lutex_t tagged_lutex)
+{
+    int ret = 0;
+    struct lutex *lutex = (struct lutex*) native_pointer(tagged_lutex);
+
+    ret = pthread_mutex_trylock(lutex->mutex);
+    /* The mutex is locked */
+    if (ret == EDEADLK || ret == EBUSY)
+        return ret;
     lutex_assert(ret == 0);
 
     return ret;
@@ -134,6 +172,10 @@ lutex_unlock (tagged_lutex_t tagged_lutex)
     struct lutex *lutex = (struct lutex*) native_pointer(tagged_lutex);
 
     ret = thread_mutex_unlock(lutex->mutex);
+    /* Unlocking unlocked mutex would occur as:
+     * (with-mutex (mutex) (cond-wait cond mutex)) */
+    if (ret == EPERM)
+        return ret;
     lutex_assert(ret == 0);
 
     return ret;
@@ -156,6 +198,12 @@ lutex_destroy (tagged_lutex_t tagged_lutex)
         lutex->mutex = NULL;
     }
 
+    if (lutex->mutexattr) {
+        pthread_mutexattr_destroy(lutex->mutexattr);
+        free(lutex->mutexattr);
+        lutex->mutexattr = NULL;
+    }
+
     return 0;
 }
 #endif