MINOR: threads: implement ha_tkill() and ha_tkillall()

These functions are used respectively to signal one thread or all threads.
When multithreading is disabled, it's always the current thread which is
signaled.

include/common/hathreads.h

@@ -22,6 +22,7 @@
 #ifndef _COMMON_HATHREADS_H
 #define _COMMON_HATHREADS_H
 
+#include <signal.h>
 #include <unistd.h>
 #ifdef _POSIX_PRIORITY_SCHEDULING
 #include <sched.h>
@@ -157,6 +158,18 @@ static inline void ha_thread_relax(void)
 #endif
 }
 
+/* send signal <sig> to thread <thr> */
+static inline void ha_tkill(unsigned int thr, int sig)
+{
+	raise(sig);
+}
+
+/* send signal <sig> to all threads */
+static inline void ha_tkillall(int sig)
+{
+	raise(sig);
+}
+
 static inline void __ha_barrier_atomic_load(void)
 {
 }
@@ -383,6 +396,8 @@ static inline unsigned long thread_isolated()
 void thread_harmless_till_end();
 void thread_isolate();
 void thread_release();
+void ha_tkill(unsigned int thr, int sig);
+void ha_tkillall(int sig);
 
 extern struct thread_info {
 	pthread_t pthread;

src/hathreads.c

@@ -97,6 +97,29 @@ void thread_release()
 	thread_harmless_end();
 }
 
+/* send signal <sig> to thread <thr> */
+void ha_tkill(unsigned int thr, int sig)
+{
+	pthread_kill(thread_info[thr].pthread, sig);
+}
+
+/* send signal <sig> to all threads. The calling thread is signaled last in
+ * order to allow all threads to synchronize in the handler.
+ */
+void ha_tkillall(int sig)
+{
+	unsigned int thr;
+
+	for (thr = 0; thr < global.nbthread; thr++) {
+		if (!(all_threads_mask & (1UL << thr)))
+			continue;
+		if (thr == tid)
+			continue;
+		pthread_kill(thread_info[thr].pthread, sig);
+	}
+	raise(sig);
+}
+
 /* these calls are used as callbacks at init time */
 void ha_spin_init(HA_SPINLOCK_T *l)
 {