Fix errors found by cppcheck

[disk.c:206]: (error) Resource leak: f
[modules.c:62]: (error) Memory leak: buffer
[modules.c:68]: (error) Common realloc mistake: 'buffer' nulled but not freed upon failure
[stage1.c:101]: (error) va_list 'args' was opened but not closed by va_end().
[url.c:297]: (error) Resource leak: dataSocket

disk.c

@@ -202,6 +202,8 @@ static enum return_type try_with_device(char *dev_name)
 
 	if (!(f = fopen("/proc/partitions", "rb")) || !fgets(buf, sizeof(buf), f) || !fgets(buf, sizeof(buf), f)) {
 		log_perror(dev_name);
+		if (f)
+		    fclose(f);
 		stg1_error_message("Could not read partitions information.");
 		return RETURN_ERROR;
 	}

modules.c

@@ -55,17 +55,27 @@ static void *grab_file(const char *filename, unsigned long *size)
 {
 	unsigned int max = 16384;
 	int ret, fd;
-	void *buffer = malloc(max);
+	void *buffer;
 
 	fd = open(filename, O_RDONLY, 0);
 	if (fd < 0)
 		return NULL;
 
+	buffer = malloc(max);
+	if (!buffer)
+		return NULL;
+
 	*size = 0;
 	while ((ret = read(fd, buffer + *size, max - *size)) > 0) {
 		*size += ret;
-		if (*size == max)
-			buffer = realloc(buffer, max *= 2);
+		if (*size == max) {
+			void *nbuffer = realloc(buffer, max *= 2);
+			if (!nbuffer) {
+				free(buffer);
+				return NULL;
+			}
+			buffer = nbuffer;
+		}
 	}
 	if (ret < 0) {
 		free(buffer);

stage1.c

@@ -98,6 +98,7 @@ void stg1_info_message(char *msg, ...)
 	va_start(args, msg);
 	if (IS_AUTOMATIC) {
 		vlog_message(msg, args);
+		va_end(args);
 		return;
 	}
 	vinfo_message(msg, args);

url.c

@@ -294,6 +294,7 @@ int ftp_data_command(int sock, char * command, char * param)
 	i = strlen(retrCommand);
    
 	if (write(sock, retrCommand, i) != i) {
+		close(dataSocket);
 		return FTPERR_SERVER_IO_ERROR;
 	}