+
+/*
+ * Expands tildes in the file name. Returns data allocated by xmalloc.
+ * Warning: this calls getpw*.
+ */
+char *
+tilde_expand_filename(const char *filename, uid_t uid)
+{
+ const char *path;
+ char user[128], ret[MAXPATHLEN];
+ struct passwd *pw;
+ int len;
+
+ if (*filename != '~')
+ return (xstrdup(filename));
+ filename++;
+
+ path = strchr(filename, '/');
+ if (path != NULL && path > filename) { /* ~user/path */
+ if (path - filename > sizeof(user) - 1)
+ fatal("tilde_expand_filename: ~username too long");
+ memcpy(user, filename, path - filename);
+ user[path - filename] = '\0';
+ if ((pw = getpwnam(user)) == NULL)
+ fatal("tilde_expand_filename: No such user %s", user);
+ } else if ((pw = getpwuid(uid)) == NULL) /* ~/path */
+ fatal("tilde_expand_filename: No such uid %d", uid);
+
+ if (strlcpy(ret, pw->pw_dir, sizeof(ret)) >= sizeof(ret))
+ fatal("tilde_expand_filename: Path too long");
+
+ /* Make sure directory has a trailing '/' */
+ len = strlen(pw->pw_dir);
+ if ((len == 0 || pw->pw_dir[len - 1] != '/') &&
+ strlcat(ret, "/", sizeof(ret)) >= sizeof(ret))
+ fatal("tilde_expand_filename: Path too long");
+
+ /* Skip leading '/' from specified path */
+ if (path != NULL)
+ filename = path + 1;
+ if (strlcat(ret, filename, sizeof(ret)) >= sizeof(ret))
+ fatal("tilde_expand_filename: Path too long");
+
+ return (xstrdup(ret));
+}
+
+/*
+ * Read an entire line from a public key file into a static buffer, discarding
+ * lines that exceed the buffer size. Returns 0 on success, -1 on failure.
+ */
+int
+read_keyfile_line(FILE *f, const char *filename, char *buf, size_t bufsz,
+ u_long *lineno)
+{
+ while (fgets(buf, bufsz, f) != NULL) {
+ (*lineno)++;
+ if (buf[strlen(buf) - 1] == '\n' || feof(f)) {
+ return 0;
+ } else {
+ debug("%s: %s line %lu exceeds size limit", __func__,
+ filename, *lineno);
+ /* discard remainder of line */
+ while (fgetc(f) != '\n' && !feof(f))
+ ; /* nothing */
+ }
+ }
+ return -1;
+}