+static void disable_old_keys(const char *filename) {
+ char tmpfile[PATH_MAX] = "";
+ char buf[1024];
+ bool disabled = false;
+ FILE *r, *w;
+
+ r = fopen(filename, "r");
+ if(!r)
+ return;
+
+ snprintf(tmpfile, sizeof tmpfile, "%s.tmp", filename);
+
+ w = fopen(tmpfile, "w");
+
+ while(fgets(buf, sizeof buf, r)) {
+ if(!strncmp(buf, "-----BEGIN RSA", 14)) {
+ buf[11] = 'O';
+ buf[12] = 'L';
+ buf[13] = 'D';
+ disabled = true;
+ }
+ else if(!strncmp(buf, "-----END RSA", 12)) {
+ buf[ 9] = 'O';
+ buf[10] = 'L';
+ buf[11] = 'D';
+ disabled = true;
+ }
+ if(w && fputs(buf, w) < 0) {
+ disabled = false;
+ break;
+ }
+ }
+
+ if(w)
+ fclose(w);
+ fclose(r);
+
+ if(!w && disabled) {
+ fprintf(stderr, "Warning: old key(s) found, remove them by hand!\n");
+ return;
+ }
+
+ if(disabled) {
+#ifdef HAVE_MINGW
+ // We cannot atomically replace files on Windows.
+ char bakfile[PATH_MAX] = "";
+ snprintf(bakfile, sizeof bakfile, "%s.bak", filename);
+ if(rename(filename, bakfile) || rename(tmpfile, filename)) {
+ rename(bakfile, filename);
+#else
+ if(rename(tmpfile, filename)) {
+#endif
+ fprintf(stderr, "Warning: old key(s) found, remove them by hand!\n");
+ } else {
+#ifdef HAVE_MINGW
+ unlink(bakfile);
+#endif
+ fprintf(stderr, "Warning: old key(s) found and disabled.\n");
+ }
+ }
+
+ unlink(tmpfile);
+}
+
+FILE *ask_and_open(const char *filename, const char *what) {