Enable tracking of pthreads mutexes

Some POSIX threads implementations (e.g. FreeBSD's libthr) allocate
memory on the heap when pthread_mutex_init() is called.  Every call to
that function must be accompanied by a corresponding call to
pthread_mutex_destroy() or else the memory allocated for the mutex will
leak.

jemalloc can be used for detecting memory allocations which are not
released by a process when it exits.  Unfortunately, since jemalloc is
also the system allocator on FreeBSD and a special (profiling-enabled)
build of jemalloc is required for memory leak detection, this method
cannot be used for detecting leaked memory allocated by libthr on a
stock FreeBSD installation.

However, libthr's behavior can be emulated on any platform by
implementing alternative versions of libisc functions for creating and
destroying mutexes that allocate memory using malloc() and release it
using free().  This enables using jemalloc for detecting missing
pthread_mutex_destroy() calls on any platform on which it works
reliably.

Introduce a new ISC_TRACK_PTHREADS_OBJECTS preprocessor macro, which
causes isc_mutex_t structures to be allocated on the heap by
isc_mutex_init() and freed by isc_mutex_destroy().  Reuse existing mutex
macros (after renaming them appropriately) for other operations.

lib/isc/condition.c

@@ -52,7 +52,15 @@ isc_condition_waituntil(isc_condition_t *c, isc_mutex_t *m, isc_time_t *t) {
 	ts.tv_nsec = (long)isc_time_nanoseconds(t);
 
 	do {
-		presult = pthread_cond_timedwait(c, m, &ts);
+		pthread_mutex_t *mutex;
+
+#ifdef ISC_TRACK_PTHREADS_OBJECTS
+		mutex = *m;
+#else  /* ISC_TRACK_PTHREADS_OBJECTS */
+		mutex = m;
+#endif /* ISC_TRACK_PTHREADS_OBJECTS */
+
+		presult = pthread_cond_timedwait(c, mutex, &ts);
 		if (presult == 0) {
 			return (ISC_R_SUCCESS);
 		}

lib/isc/include/isc/condition.h

@@ -33,7 +33,13 @@ typedef pthread_cond_t isc_condition_t;
 		ERRNO_CHECK(pthread_cond_init, _ret);     \
 	}
 
-#define isc_condition_wait(cp, mp) \
+#ifdef ISC_TRACK_PTHREADS_OBJECTS
+#define isc_condition_wait(cp, mp) isc__condition_wait(cp, *mp)
+#else /* ISC_TRACK_PTHREADS_OBJECTS */
+#define isc_condition_wait(cp, mp) isc__condition_wait(cp, mp)
+#endif /* ISC_TRACK_PTHREADS_OBJECTS */
+
+#define isc__condition_wait(cp, mp) \
 	RUNTIME_CHECK(pthread_cond_wait((cp), (mp)) == 0)
 
 #define isc_condition_signal(cp) RUNTIME_CHECK(pthread_cond_signal((cp)) == 0)

lib/isc/include/isc/mutex.h

@@ -17,26 +17,59 @@
 
 #include <pthread.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #include <isc/lang.h>
 #include <isc/result.h> /* for ISC_R_ codes */
+#include <isc/util.h>
 
 ISC_LANG_BEGINDECLS
 
+#ifdef ISC_TRACK_PTHREADS_OBJECTS
+
+typedef pthread_mutex_t *isc_mutex_t;
+
+#define isc_mutex_init(mp)                  \
+	{                                   \
+		*mp = malloc(sizeof(**mp)); \
+		isc__mutex_init((*mp));     \
+	}
+#define isc_mutex_lock(mp)    isc__mutex_lock(*mp)
+#define isc_mutex_unlock(mp)  isc__mutex_unlock(*mp)
+#define isc_mutex_trylock(mp) isc__mutex_trylock(*mp)
+#define isc_mutex_destroy(mp)            \
+	{                                \
+		isc__mutex_destroy(*mp); \
+		free(*mp);               \
+	}
+
+#else /* ISC_TRACK_PTHREADS_OBJECTS */
+
 typedef pthread_mutex_t isc_mutex_t;
 
-void
-isc__mutex_init(isc_mutex_t *mp);
+#define isc_mutex_init(mp)    isc__mutex_init((mp))
+#define isc_mutex_lock(mp)    isc__mutex_lock(mp)
+#define isc_mutex_unlock(mp)  isc__mutex_unlock(mp)
+#define isc_mutex_trylock(mp) isc__mutex_trylock(mp)
+#define isc_mutex_destroy(mp) isc__mutex_destroy(mp)
 
-#define isc_mutex_init(mp) isc__mutex_init((mp))
+#endif /* ISC_TRACK_PTHREADS_OBJECTS */
 
-#define isc_mutex_lock(mp) RUNTIME_CHECK(pthread_mutex_lock((mp)) == 0)
+extern pthread_mutexattr_t isc__mutex_init_attr;
 
-#define isc_mutex_unlock(mp) RUNTIME_CHECK(pthread_mutex_unlock((mp)) == 0)
+#define isc__mutex_init(mp)                                               \
+	{                                                                 \
+		int _ret = pthread_mutex_init(mp, &isc__mutex_init_attr); \
+		ERRNO_CHECK(pthread_mutex_init, _ret);                    \
+	}
 
-#define isc_mutex_trylock(mp) \
+#define isc__mutex_lock(mp) RUNTIME_CHECK(pthread_mutex_lock((mp)) == 0)
+
+#define isc__mutex_unlock(mp) RUNTIME_CHECK(pthread_mutex_unlock((mp)) == 0)
+
+#define isc__mutex_trylock(mp) \
 	((pthread_mutex_trylock((mp)) == 0) ? ISC_R_SUCCESS : ISC_R_LOCKBUSY)
 
-#define isc_mutex_destroy(mp) RUNTIME_CHECK(pthread_mutex_destroy((mp)) == 0)
+#define isc__mutex_destroy(mp) RUNTIME_CHECK(pthread_mutex_destroy((mp)) == 0)
 
 ISC_LANG_ENDDECLS

lib/isc/mutex.c

@@ -47,14 +47,6 @@ isc__mutex_initialize(void) {
 		      ISC_R_SUCCESS);
 }
 
-void
-isc__mutex_init(isc_mutex_t *mp) {
-	int err;
-
-	err = pthread_mutex_init(mp, &isc__mutex_init_attr);
-	ERRNO_CHECK(pthread_mutex_init, err);
-}
-
 void
 isc__mutex_shutdown(void) {
 	/* noop */;