TaskVine: Fix buffer null terminate (#3547)

* Must null-terminate buffer received from worker before treating as a string.

* Worker source needs to be an explicit dependency.

* fix

* format

---------

Co-authored-by: Douglas Thain <[email protected]>

Author: tphung3

taskvine/src/worker/Makefile

@@ -11,7 +11,8 @@ SOURCES = \
 	vine_transfer_server.c \
 	vine_process.c \
 	vine_watcher.c \
-	vine_gpus.c
+	vine_gpus.c \
+	vine_worker.c
 
 OBJECTS = $(SOURCES:%.c=%.o)
 PROGRAMS = vine_worker

taskvine/src/worker/vine_worker.c

@@ -693,11 +693,16 @@ static int reap_completed_function_call(struct vine_process *p, struct link *man
 	int len_buffer = atoi(buffer);
 
 	/* now read the buffer, which is the task id of the done function invocation. */
-	char buffer_data[len_buffer];
+	char buffer_data[len_buffer + 1];
 	ok = link_read(p->library_read_link, buffer_data, len_buffer, time(0) + active_timeout);
 	if (ok <= 0) {
 		return 0;
 	}
+
+	/* null terminate the buffer before treating it as a string. */
+	buffer_data[ok] = 0;
+
+	/* parse out the taskid of the completed task */
 	uint64_t done_task_id = (uint64_t)strtoul(buffer_data, NULL, 10);
 	debug(D_VINE, "Received result for function %" PRIu64, done_task_id);