1 files changed, 29 insertions, 10 deletions
diff --git a/lock.c b/lock.c
index aaac35a..68245ac 100644
--- a/lock.c
+++ b/lock.c
@@ -1,5 +1,4 @@
 /* See LICENSE for licence details. */
-#include <errno.h>
 #include <string.h>
 #include <stdio.h>
 #include <unistd.h>
@@ -15,19 +14,39 @@ int main(int argc, char **argv){
 		return EXIT_FAILURE;
 	}
 
-	/* create lock */
-	if(mkdir(argv[1], S_IRUSR | S_IXUSR)){
-		if(errno && errno != EEXIST) {
+	if(access(argv[1], F_OK)){
+		/* create lock */
+		if(mkdir(argv[1], S_IRUSR | S_IXUSR)){
 			fprintf(stderr, "Failed to create lock %s.\n", argv[1]);
 			return EXIT_FAILURE;
 		}
-		/* lock exists */
-		for(; mkdir(argv[1], S_IRUSR | S_IXUSR);){
-			sleep(1);
-		}
-		return EXIT_SUCCESS;
-	} else
 		return EXIT_SUCCESS;
 	}
 	
+	/* prepare path */
+	argvlen = strlen(argv[1]);
+	pathlen = argvlen + sizeof("/..") + 1;
+	path = malloc(pathlen);
+	if(path == NULL) {
+		fprintf(stderr, "malloc() failed\n");
+		return EXIT_FAILURE;
+	}
+	
+	memcpy(path, argv[1], argvlen);
+	memcpy(path + argvlen, "/..\0", sizeof("/..") + 1);
+
+	if(access(path, F_OK)){
+		/* invalid lock */
+		fprintf(stderr, "%s is not a lock directory.\n", argv[1]);
+		free(path);
+		return EXIT_FAILURE;
+	}
+	
+	/* lock exists */
+	for(; !access(path, F_OK) ;){
+		sleep(1);
+	}
+
+	free(path);
+	return EXIT_SUCCESS;
 }