+static int open_wim_writable(WIMStruct *w, const char *path,
+ bool trunc, bool readable)
+{
+ const char *mode;
+ int ret = 0;
+ if (trunc)
+ if (readable)
+ mode = "w+b";
+ else
+ mode = "wb";
+ else
+ mode = "r+b";
+
+ DEBUG("Opening `%s' read-write", path);
+ wimlib_assert(w->out_fp == NULL);
+ wimlib_assert(path != NULL);
+ w->out_fp = fopen(path, mode);
+ if (!w->out_fp) {
+ ERROR_WITH_ERRNO("Failed to open `%s' for writing", path);
+ return WIMLIB_ERR_OPEN;
+ }
+#if defined(HAVE_SYS_FILE_H) && defined(HAVE_FLOCK)
+ if (!trunc) {
+ ret = flock(fileno(w->out_fp), LOCK_EX | LOCK_NB);
+ if (ret != 0) {
+ if (errno == EWOULDBLOCK) {
+ ERROR("`%s' is already being modified "
+ "by another process", path);
+ ret = WIMLIB_ERR_ALREADY_LOCKED;
+ fclose(w->out_fp);
+ w->out_fp = NULL;
+ } else {
+ WARNING("Failed to lock `%s': %s",
+ path, strerror(errno));
+ ret = 0;
+ }
+ }
+ }
+#endif
+ return ret;
+}
+
+