+ int dfd;
+
+ dfd = open(file_name, O_RDWR | O_CREAT | O_TRUNC | O_BINARY,
+ S_IRUSR | S_IWUSR);
+ if (dfd < 0) {
+ fprintf(stderr, "Can't open \"%s\": %s\n",
+ file_name, strerror(errno));
+ return -1;
+ }
+
+ if (write(dfd, (void *)file_data, file_len) != (ssize_t)file_len) {
+ fprintf(stderr, "Write error on \"%s\": %s\n",
+ file_name, strerror(errno));
+ close(dfd);
+ return -1;
+ }
+
+ close(dfd);
+
+ return 0;
+}
+
+int imagetool_get_filesize(struct image_tool_params *params, const char *fname)
+{
+ struct stat sbuf;
+ int fd;
+
+ fd = open(fname, O_RDONLY | O_BINARY);
+ if (fd < 0) {
+ fprintf(stderr, "%s: Can't open %s: %s\n",
+ params->cmdname, fname, strerror(errno));
+ return -1;
+ }
+
+ if (fstat(fd, &sbuf) < 0) {
+ fprintf(stderr, "%s: Can't stat %s: %s\n",
+ params->cmdname, fname, strerror(errno));
+ close(fd);
+ return -1;
+ }
+ close(fd);
+
+ return sbuf.st_size;
+}
+
+time_t imagetool_get_source_date(
+ const char *cmdname,
+ time_t fallback)
+{
+ char *source_date_epoch = getenv("SOURCE_DATE_EPOCH");
+
+ if (source_date_epoch == NULL)
+ return fallback;
+
+ time_t time = (time_t) strtol(source_date_epoch, NULL, 10);
+
+ if (gmtime(&time) == NULL) {
+ fprintf(stderr, "%s: SOURCE_DATE_EPOCH is not valid\n",
+ cmdname);
+ time = 0;
+ }
+
+ return time;