Add Semaphores to r_util and use them for joining Tasks (#10622)

* Add Semaphores to r_util

* Use Semaphore for joining Tasks

libr/core/task.c

@@ -63,11 +63,12 @@ R_API void r_core_task_list(RCore *core, int mode) {
 }
 
 static void task_join(RCoreTask *task) {
-	RThreadLock *lock = task->running_lock;
-	if (!lock) {
+	RThreadSemaphore *sem = task->running_sem;
+	if (!sem) {
 		return;
 	}
-	r_th_lock_wait (lock);
+	r_th_sem_wait (sem);
+	r_th_sem_post (sem);
 }
 
 R_API void r_core_task_join(RCore *core, RCoreTask *current, RCoreTask *task) {
@@ -109,7 +110,7 @@ R_API RCoreTask *r_core_task_new(RCore *core, bool create_cons, const char *cmd,
 	task->cmd = cmd ? strdup (cmd) : NULL;
 	task->cmd_log = false;
 	task->res = NULL;
-	task->running_lock = NULL;
+	task->running_sem = NULL;
 	task->dispatch_cond = r_th_cond_new ();
 	task->dispatch_lock = r_th_lock_new (false);
 	if (!task->dispatch_cond || !task->dispatch_lock) {
@@ -143,7 +144,7 @@ R_API void r_core_task_free (RCoreTask *task) {
 	free (task->cmd);
 	free (task->res);
 	r_th_free (task->thread);
-	r_th_lock_free (task->running_lock);
+	r_th_sem_free (task->running_sem);
 	r_th_cond_free (task->dispatch_cond);
 	r_th_lock_free (task->dispatch_lock);
 	r_cons_context_free (task->cons_context);
@@ -271,8 +272,8 @@ static int task_run(RCoreTask *task) {
 		task->cb (task->user, task->res);
 	}
 
-	if (task->running_lock) {
-		r_th_lock_leave (task->running_lock);
+	if (task->running_sem) {
+		r_th_sem_post (task->running_sem);
 	}
 
 	return res;
@@ -284,11 +285,11 @@ static int task_run_thread(RThread *th) {
 
 R_API void r_core_task_enqueue(RCore *core, RCoreTask *task) {
 	r_th_lock_enter (core->tasks_lock);
-	if (!task->running_lock) {
-		task->running_lock = r_th_lock_new (false);
+	if (!task->running_sem) {
+		task->running_sem = r_th_sem_new (1);
 	}
-	if (task->running_lock) {
-		r_th_lock_enter (task->running_lock);
+	if (task->running_sem) {
+		r_th_sem_wait (task->running_sem);
 	}
 	r_list_append (core->tasks, task);
 	task->thread = r_th_new (task_run_thread, task, 0);

libr/include/r_core.h

@@ -721,7 +721,7 @@ typedef enum {
 typedef struct r_core_task_t {
 	int id;
 	RTaskState state;
-	RThreadLock *running_lock;
+	RThreadSemaphore *running_sem;
 	void *user;
 	RCore *core;
 	RThreadCond *dispatch_cond;

libr/include/r_th.h

@@ -11,14 +11,17 @@
 #define R_TH_TID HANDLE
 #define R_TH_LOCK_T CRITICAL_SECTION
 #define R_TH_COND_T CONDITION_VARIABLE
+#define R_TH_SEM_T HANDLE
 //HANDLE
 
 #elif HAVE_PTHREAD
 #define __GNU
+#include <semaphore.h>
 #include <pthread.h>
 #define R_TH_TID pthread_t
 #define R_TH_LOCK_T pthread_mutex_t
 #define R_TH_COND_T pthread_cond_t
+#define R_TH_SEM_T sem_t
 
 #else
 #error Threading library only supported for pthread and w32
@@ -30,6 +33,10 @@
 extern "C" {
 #endif
 
+typedef struct r_th_sem_t {
+	R_TH_SEM_T sem;
+} RThreadSemaphore;
+
 typedef struct r_th_lock_t {
 	int refs;
 	R_TH_LOCK_T lock;
@@ -71,6 +78,11 @@ R_API bool r_th_pause(RThread *th, bool enable);
 R_API bool r_th_try_pause(RThread *th);
 R_API R_TH_TID r_th_self(void);
 
+R_API RThreadSemaphore *r_th_sem_new(unsigned int initial);
+R_API void r_th_sem_free(RThreadSemaphore *sem);
+R_API void r_th_sem_post(RThreadSemaphore *sem);
+R_API void r_th_sem_wait(RThreadSemaphore *sem);
+
 R_API RThreadLock *r_th_lock_new(bool recursive);
 R_API int r_th_lock_wait(RThreadLock *th);
 R_API int r_th_lock_check(RThreadLock *thl);

libr/util/Makefile

@@ -15,7 +15,7 @@ OBJS=binheap.o mem.o pool.o unum.o str.o hex.o file.o range.o tinyrange.o
 OBJS+=prof.o cache.o sys.o buf.o w32-sys.o ubase64.o base85.o base91.o
 OBJS+=list.o flist.o mixed.o btree.o chmod.o graph.o
 OBJS+=regex/regcomp.o regex/regerror.o regex/regexec.o uleb128.o
-OBJS+=sandbox.o calc.o thread.o thread_lock.o thread_cond.o
+OBJS+=sandbox.o calc.o thread.o thread_sem.o thread_lock.o thread_cond.o
 OBJS+=strpool.o bitmap.o date.o format.o pie.o print.o ctype.o
 OBJS+=seven.o slist.o randomart.o log.o zip.o debruijn.o
 OBJS+=utf8.o utf16.o utf32.o strbuf.o lib.o name.o spaces.o signal.o syscmd.o

libr/util/meson.build

@@ -62,6 +62,7 @@ files = [
   'sys.c',
   'syscmd.c',
   'thread.c',
+  'thread_sem.c',
   'thread_lock.c',
   'thread_cond.c',
   'thread_pipe.c',

libr/util/thread_sem.c

@@ -0,0 +1,51 @@
+/* radare2 - LGPL - Copyright 2018 - thestr4ng3r */
+
+#include <r_th.h>
+
+R_API RThreadSemaphore *r_th_sem_new(unsigned int initial) {
+	RThreadSemaphore *sem = R_NEW (RThreadSemaphore);
+	if (!sem) {
+		return NULL;
+	}
+#if HAVE_PTHREAD
+	if (sem_init (&sem->sem, 0, initial) != 0) {
+		free (sem);
+		return NULL;
+	}
+#elif __WINDOWS__ && !defined(__CYGWIN__)
+	sem->sem = CreateSemaphore (NULL, (LONG)initial, ST32_MAX, NULL);
+	if (!sem->sem) {
+		free (sem);
+		return NULL;
+	}
+#endif
+	return sem;
+}
+
+R_API void r_th_sem_free(RThreadSemaphore *sem) {
+	if (!sem) {
+		return;
+	}
+#if HAVE_PTHREAD
+	sem_destroy (&sem->sem);
+#elif __WINDOWS__ && !defined(__CYGWIN__)
+	CloseHandle (sem->sem);
+#endif
+	free (sem);
+}
+
+R_API void r_th_sem_post(RThreadSemaphore *sem) {
+#if HAVE_PTHREAD
+	sem_post (&sem->sem);
+#elif __WINDOWS__ && !defined(__CYGWIN__)
+	ReleaseSemaphore (sem->sem, 1, NULL);
+#endif
+}
+
+R_API void r_th_sem_wait(RThreadSemaphore *sem) {
+#if HAVE_PTHREAD
+	sem_wait (&sem->sem);
+#elif __WINDOWS__ && !defined(__CYGWIN__)
+	WaitForSingleObject (sem->sem, INFINITE);
+#endif
+}