+static int log_ref_write_fd(int fd, const unsigned char *old_sha1,
+ const unsigned char *new_sha1,
+ const char *committer, const char *msg)
+{
+ int msglen, written;
+ unsigned maxlen, len;
+ char *logrec;
+
+ msglen = msg ? strlen(msg) : 0;
+ maxlen = strlen(committer) + msglen + 100;
+ logrec = xmalloc(maxlen);
+ len = sprintf(logrec, "%s %s %s\n",
+ sha1_to_hex(old_sha1),
+ sha1_to_hex(new_sha1),
+ committer);
+ if (msglen)
+ len += copy_msg(logrec + len - 1, msg) - 1;
+
+ written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
+ free(logrec);
+ if (written != len)
+ return -1;
+
+ return 0;
+}
+