+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;
+ }
+
+ int len = snprintf(tmpfile, sizeof(tmpfile), "%s.tmp", filename);
+
+ if(len < 0 || len >= PATH_MAX) {
+ fprintf(stderr, "Pathname too long: %s.tmp\n", filename);
+ w = NULL;
+ } else {
+ 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) {
+ FILE *r;
+ char directory[PATH_MAX];
+ char line[PATH_MAX];
+ char abspath[PATH_MAX];
+ const char *fn;
+
+ /* Check stdin and stdout */
+ if(!isatty(0) || !isatty(1)) {
+ /* Argh, they are running us from a script or something. Write
+ the files to the current directory and let them burn in hell
+ for ever. */
+ fn = filename;
+ } else {
+ /* Ask for a file and/or directory name. */
+ fprintf(stdout, "Please enter a file to save %s to [%s]: ",
+ what, filename);
+ fflush(stdout);
+
+ fn = readline(stdin, line, sizeof(line));
+
+ if(!fn) {
+ fprintf(stderr, "Error while reading stdin: %s\n",
+ strerror(errno));
+ return NULL;
+ }
+
+ if(!strlen(fn))
+ /* User just pressed enter. */
+ {
+ fn = filename;
+ }
+ }
+
+#ifdef HAVE_MINGW
+
+ if(fn[0] != '\\' && fn[0] != '/' && !strchr(fn, ':')) {
+#else
+
+ if(fn[0] != '/') {
+#endif
+ /* The directory is a relative path or a filename. */
+ getcwd(directory, sizeof(directory));
+
+ if((size_t)snprintf(abspath, sizeof(abspath), "%s/%s", directory, fn) >= sizeof(abspath)) {
+ fprintf(stderr, "Pathname too long: %s/%s\n", directory, fn);
+ return NULL;
+ }
+
+ fn = abspath;
+ }
+
+ umask(0077); /* Disallow everything for group and other */
+
+ disable_old_keys(fn);
+
+ /* Open it first to keep the inode busy */
+
+ r = fopen(fn, "a");
+
+ if(!r) {
+ fprintf(stderr, "Error opening file `%s': %s\n",
+ fn, strerror(errno));
+ return NULL;
+ }
+
+ return r;
+}
+
+