From e196fa9f981da1eee2313f6817318397ea74f5d5 Mon Sep 17 00:00:00 2001
From: David Phillips <david@sighup.nz>
Date: Tue, 28 Aug 2018 15:28:49 +1200
Subject: Handle clients in separate threads, add mutexes

---
 alarmd/Makefile      |  6 ++++--
 alarmd/alarmd.c      | 35 ++++++++++++++++++++---------------
 alarmd/alarmd_lock.c | 21 +++++++++++++++++++++
 alarmd/alarmd_lock.h |  3 +++
 4 files changed, 48 insertions(+), 17 deletions(-)
 create mode 100644 alarmd/alarmd_lock.c
 create mode 100644 alarmd/alarmd_lock.h

diff --git a/alarmd/Makefile b/alarmd/Makefile
index 9c69056..4e016ea 100644
--- a/alarmd/Makefile
+++ b/alarmd/Makefile
@@ -1,7 +1,9 @@
-LDFLAGS += -L../lib -lalarm -luuid
+LDFLAGS += -L../lib -lalarm -luuid -lpthread
 CFLAGS += -I../inc
 
 all: alarmd
 
+alarmd: alarmd.o alarmd_lock.o
+
 clean:
-	rm alarmd
+	rm alarmd alarmd.o alarmd_lock.o
diff --git a/alarmd/alarmd.c b/alarmd/alarmd.c
index 9f2c254..900aa52 100644
--- a/alarmd/alarmd.c
+++ b/alarmd/alarmd.c
@@ -13,7 +13,9 @@
 #include <uuid/uuid.h>
 #include <sys/un.h>
 #include <uthash.h>
+#include <pthread.h>
 
+#include "alarmd_lock.h"
 #include "alarmd_proto.h"
 
 struct alarm {
@@ -72,9 +74,9 @@ int handle_register(int c_sock, pid_t owner)
 	new_alarm->is_raised = 0;
 	new_alarm->owner = owner;
 
-	/* LOCK */
+	alarmd_lock();
 	HASH_ADD(hh, alarms, uuid, sizeof(uuid), new_alarm);
-	/* UNLOCK */
+	alarmd_unlock();
 	return 0;
 }
 
@@ -82,22 +84,22 @@ int handle_deregister(int c_sock)
 {
 	uuid_t uuid;
 	struct alarm *target = NULL;
-	char uuid_str[37];
+//	char uuid_str[37];
 
 	if (recv(c_sock, &uuid, sizeof(uuid_t), 0) < sizeof(uuid_t)) {
 		return 1;
 	}
 
-	uuid_unparse(uuid, uuid_str);
-	fprintf(stderr, "Deregistering alarm %s\n", uuid_str);
+//	uuid_unparse(uuid, uuid_str);
+//	fprintf(stderr, "Deregistering alarm %s\n", uuid_str);
 
-	/* LOCK */
+	alarmd_lock();
 	HASH_FIND(hh, alarms, uuid, sizeof(uuid_t), target);
 	if (target != NULL) {
 		HASH_DEL(alarms, target);
 		free(target);
 	}
-	/* UNLOCK */
+	alarmd_unlock();
 
 	return 0;
 }
@@ -113,12 +115,12 @@ int handle_set_raised_generic(int c_sock, int shall_raise)
 		return 1;
 	}
 
-	/* LOCK */
+	alarmd_lock();
 	HASH_FIND(hh, alarms, uuid, sizeof(uuid_t), target);
 	if (target != NULL) {
 		target->is_raised = shall_raise;
 	}
-	/* UNLOCK */
+	alarmd_unlock();
 	return 0;
 }
 
@@ -139,7 +141,7 @@ int handle_query(int c_sock)
 	struct alarm *a = NULL;
 	struct alarm *tmp = NULL;
 
-	/* LOCK */
+	alarmd_lock();
 	count = HASH_COUNT(alarms);
 
 	if (send(c_sock, &count, sizeof(count), 0) < sizeof(count)) {
@@ -162,12 +164,13 @@ int handle_query(int c_sock)
 			perror("send");
 		}
 	}
-	/* UNLOCK */
+	alarmd_unlock();
 	return 0;
 }
 
-void handle_client(int c_sock)
+void *handle_client(void *c_sock_)
 {
+	int c_sock = *((int*)c_sock_);
 	uint32_t packet_type = 0;
 	ssize_t nread = 0;
 	unsigned int cred_len = 0;
@@ -185,12 +188,12 @@ void handle_client(int c_sock)
 		nread = recv(c_sock, &packet_type, sizeof(packet_type), 0);
 		if (nread < 0) {
 			perror("recv");
-			return;
+			return NULL;
 		} else if (nread == 0) {
 			break;
 		} else if (nread < sizeof(packet_type)) {
 			fprintf(stderr, "Packet type too short\n");
-			return;
+			return NULL;
 		}
 
 		switch(packet_type) {
@@ -225,6 +228,7 @@ void handle_client(int c_sock)
 		}
 	}
 	close(c_sock);
+	return NULL;
 }
 
 int main(int argc, char **argv)
@@ -263,7 +267,8 @@ int main(int argc, char **argv)
 			perror("accept");
 			return 1;
 		}
-		handle_client(c_sock);
+		pthread_t thread;
+		pthread_create(&thread, NULL, handle_client, &c_sock);
 	}
 	fprintf(stderr, "Shutting down\n");
 	close(sock);
diff --git a/alarmd/alarmd_lock.c b/alarmd/alarmd_lock.c
new file mode 100644
index 0000000..9770183
--- /dev/null
+++ b/alarmd/alarmd_lock.c
@@ -0,0 +1,21 @@
+#include <pthread.h>
+
+static pthread_mutex_t alarmd_global_lock = PTHREAD_MUTEX_INITIALIZER;
+
+
+int alarmd_lock_destroy()
+{
+	return pthread_mutex_destroy(&alarmd_global_lock);
+}
+
+
+int alarmd_lock()
+{
+	return pthread_mutex_lock(&alarmd_global_lock);
+}
+
+
+int alarmd_unlock()
+{
+	return pthread_mutex_unlock(&alarmd_global_lock);
+}
diff --git a/alarmd/alarmd_lock.h b/alarmd/alarmd_lock.h
new file mode 100644
index 0000000..ea60726
--- /dev/null
+++ b/alarmd/alarmd_lock.h
@@ -0,0 +1,3 @@
+int alarmd_lock_destroy();
+int alarmd_lock();
+int alarmd_unlock();
-- 
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