+/*
+ * Try to read the location of the git directory from the .git file,
+ * return path to git directory if found.
+ */
+const char *read_gitfile_gently(const char *path)
+{
+ char *buf;
+ struct stat st;
+ int fd;
+ size_t len;
+
+ if (stat(path, &st))
+ return NULL;
+ if (!S_ISREG(st.st_mode))
+ return NULL;
+ fd = open(path, O_RDONLY);
+ if (fd < 0)
+ die("Error opening %s: %s", path, strerror(errno));
+ buf = xmalloc(st.st_size + 1);
+ len = read_in_full(fd, buf, st.st_size);
+ close(fd);
+ if (len != st.st_size)
+ die("Error reading %s", path);
+ buf[len] = '\0';
+ if (prefixcmp(buf, "gitdir: "))
+ die("Invalid gitfile format: %s", path);
+ while (buf[len - 1] == '\n' || buf[len - 1] == '\r')
+ len--;
+ if (len < 9)
+ die("No path in gitfile: %s", path);
+ buf[len] = '\0';
+ if (!is_git_directory(buf + 8))
+ die("Not a git repository: %s", buf + 8);
+ path = make_absolute_path(buf + 8);
+ free(buf);
+ return path;
+}
+