Function read_gitfile_gently

setup.c:956–1035

* Try to read the location of the git directory from the .git file, * return path to git directory if found. The return value comes from * a shared buffer. * * On failure, if return_error_code is not NULL, return_error_code * will be set to an error code and NULL will be returned. If * return_error_code is NULL the function will die instead (for most * cases). */

 * cases).
 */
const char *read_gitfile_gently(const char *path, int *return_error_code)
{
	const int max_file_size = 1 << 20;  /* 1MB */
	int error_code = 0;
	char *buf = NULL;
	char *dir = NULL;
	const char *slash;
	struct stat st;
	int fd;
	ssize_t len;
	static struct strbuf realpath = STRBUF_INIT;

	if (stat(path, &st)) {
		if (errno == ENOENT || errno == ENOTDIR)
			error_code = READ_GITFILE_ERR_MISSING;
		else
			error_code = READ_GITFILE_ERR_STAT_FAILED;
		goto cleanup_return;
	}
	if (S_ISDIR(st.st_mode)) {
		error_code = READ_GITFILE_ERR_IS_A_DIR;
		goto cleanup_return;
	}
	if (!S_ISREG(st.st_mode)) {
		error_code = READ_GITFILE_ERR_NOT_A_FILE;
		goto cleanup_return;
	}
	if (st.st_size > max_file_size) {
		error_code = READ_GITFILE_ERR_TOO_LARGE;
		goto cleanup_return;
	}
	fd = open(path, O_RDONLY);
	if (fd < 0) {
		error_code = READ_GITFILE_ERR_OPEN_FAILED;
		goto cleanup_return;
	}
	buf = xmallocz(st.st_size);
	len = read_in_full(fd, buf, st.st_size);
	close(fd);
	if (len != st.st_size) {
		error_code = READ_GITFILE_ERR_READ_FAILED;
		goto cleanup_return;
	}
	if (!starts_with(buf, "gitdir: ")) {
		error_code = READ_GITFILE_ERR_INVALID_FORMAT;
		goto cleanup_return;
	}
	while (buf[len - 1] == '\n' || buf[len - 1] == '\r')
		len--;
	if (len < 9) {
		error_code = READ_GITFILE_ERR_NO_PATH;
		goto cleanup_return;
	}
	buf[len] = '\0';
	dir = buf + 8;

	if (!is_absolute_path(dir) && (slash = strrchr(path, '/'))) {
		size_t pathlen = slash+1 - path;