- strbuf_realpath(&realpath, src->buf, 1);
- if (!link(realpath.buf, dest->buf))
+ if (!link(src->buf, dest->buf)) {
+ struct stat st;
+
+ /*
+ * Sanity-check whether the created hardlink
+ * actually links to the expected file now. This
+ * catches time-of-check-time-of-use bugs in
+ * case the source file was meanwhile swapped.
+ */
+ if (lstat(dest->buf, &st))
+ die(_("hardlink cannot be checked at '%s'"), dest->buf);
+ if (st.st_mode != iter->st.st_mode ||
+ st.st_ino != iter->st.st_ino ||
+ st.st_dev != iter->st.st_dev ||
+ st.st_size != iter->st.st_size ||
+ st.st_uid != iter->st.st_uid ||
+ st.st_gid != iter->st.st_gid)
+ die(_("hardlink different from source at '%s'"), dest->buf);
+