daemon: improve threading logic on null proto.

Functions now prevent interruptions that can produce an inconsistent
state in the program.
Also, cosmetic changes.

Signed-off-by: Gediminas Jakutis <gediminas@varciai.lt>

2 files changed, 77 insertions, 41 deletions

diff --git a/src/daemon/proto_stdio.c b/src/daemon/proto_stdio.c
index 533dc76..f0a22a6 100644
--- a/src/daemon/proto_stdio.c
+++ b/src/daemon/proto_stdio.c
@@ -26,59 +26,93 @@
 
 void message_receive(char *arg)
 {
-    int done = 0;
-    while(!done)
-    {
-        pthread_mutex_lock(&state.out_m);
-        if(!state.writebuf)
-        {
-            state.writebuf = strdup(arg);
-            done = 1;
-        }
-        pthread_mutex_unlock(&state.out_m);
-    }
+	int cancelstate;
+	int done = 0;
+
+	while (!done) {
+		pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cancelstate);
+		pthread_mutex_lock(&state.out_m);
+		if (!state.writebuf) {
+			state.writebuf = strdup(arg);
+			done = 1;
+		}
+		pthread_mutex_unlock(&state.out_m);
+		pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, &cancelstate);
+		pthread_testcancel();
+	}
 }
 
-char * message_send(void)
+char *message_send(void)
 {
-    char * ret;
-    pthread_mutex_lock(&state.out_m);
-    ret = strdup(state.writebuf);
-    free(state.writebuf);
-    state.writebuf = NULL;
-    pthread_mutex_unlock(&state.out_m);
-    return ret;
+	char *ret;
+	int cancelstate;
+
+	pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cancelstate);
+	pthread_mutex_lock(&state.out_m);
+	ret = strdup(state.readbuf);
+	free(state.readbuf);
+	state.readbuf = NULL;
+	state.readbufsize = 0;
+	pthread_mutex_unlock(&state.out_m);
+	pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, &cancelstate);
+	pthread_testcancel();
+
+	return ret;
 }
 
 static void *read_stdin(void *arg)
 {
-    while(1)
-    {
-        pthread_mutex_lock(&state.in_m);
-        if(!state.readbuf)
-        {
-            state.readbufsize = getline(&state.readbuf,NULL, stdin);    
-        }
-        pthread_mutex_unlock(&state.in_m);
-    }
-    return NULL;
+	int cancelstate;
+
+	(void) arg;
+
+	while(1) {
+		pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cancelstate);
+		pthread_mutex_lock(&state.in_m);
+
+		if (!state.readbuf) {
+			state.readbufsize = getline(&state.readbuf, NULL, stdin);
+		}
+
+		pthread_mutex_unlock(&state.in_m);
+		pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, &cancelstate);
+		pthread_testcancel();
+		nanosleep(&respite, NULL);
+	}
+
+	return NULL;
 }
 
 
 static void *write_stdout(void *arg)
 {
-	while(1)
-    {
-        pthread_mutex_lock(&state.out_m);
-        if(state.writebuf)
-        {
-            printf("%s", state.writebuf);
-            free(state.writebuf);
-            state.writebuf = NULL;
-        }
-        pthread_mutex_unlock(&state.out_m);
-    }
-    return NULL;
+	int cancelstate;
+
+	(void) arg;
+
+	while(1) {
+		pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cancelstate);
+		pthread_mutex_lock(&state.out_m);
+
+		if (state.writebuf) {
+			if (state.writebuf[strlen(state.writebuf) - 1] == '\n') {
+				printf("%s", state.writebuf);
+			} else {
+				printf("%s\n", state.writebuf);
+			}
+
+			free(state.writebuf);
+			state.writebuf = NULL;
+			state.writebufsize = 0;
+		}
+
+		pthread_mutex_unlock(&state.out_m);
+		pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, &cancelstate);
+		pthread_testcancel();
+		nanosleep(&respite, NULL);
+	}
+
+	return NULL;
 }
 
 
diff --git a/src/daemon/proto_stdio_private.h b/src/daemon/proto_stdio_private.h
index 4b0ab6f..209d191 100644
--- a/src/daemon/proto_stdio_private.h
+++ b/src/daemon/proto_stdio_private.h
@@ -42,4 +42,6 @@ static struct state {
 static void *read_stdin(void *arg);
 static void *write_stdout(void *arg);
 
+static const struct timespec respite = {0, 10 * 1000 * 1000};	/* 10ms */
+
 #endif /* USURPATION_PROTO_STDIO_PRIVATE_H */