+/* We allow "recursive" symbolic refs. Only within reason, though */
+#define MAXDEPTH 5
+
+#ifndef USE_SYMLINK_HEAD
+#define USE_SYMLINK_HEAD 1
+#endif
+
+int validate_symref(const char *path)
+{
+ struct stat st;
+ char *buf, buffer[256];
+ int len, fd;
+
+ if (lstat(path, &st) < 0)
+ return -1;
+
+ /* Make sure it is a "refs/.." symlink */
+ if (S_ISLNK(st.st_mode)) {
+ len = readlink(path, buffer, sizeof(buffer)-1);
+ if (len >= 5 && !memcmp("refs/", buffer, 5))
+ return 0;
+ return -1;
+ }
+
+ /*
+ * Anything else, just open it and try to see if it is a symbolic ref.
+ */
+ fd = open(path, O_RDONLY);
+ if (fd < 0)
+ return -1;
+ len = read(fd, buffer, sizeof(buffer)-1);
+ close(fd);
+
+ /*
+ * Is it a symbolic ref?
+ */
+ if (len < 4 || memcmp("ref:", buffer, 4))
+ return -1;
+ buf = buffer + 4;
+ len -= 4;
+ while (len && isspace(*buf))
+ buf++, len--;
+ if (len >= 5 && !memcmp("refs/", buf, 5))
+ return 0;
+ return -1;
+}
+
+const char *resolve_ref(const char *path, unsigned char *sha1, int reading)