- /* Make sure the directory exists */
- memcpy(buffer, filename, dirlen);
- buffer[dirlen-1] = 0;
- if (mkdir(buffer, 0777) && errno != EEXIST)
+ /*
+ * Make sure the directory exists; note that the contents
+ * of the buffer are undefined after mkstemp returns an
+ * error, so we have to rewrite the whole buffer from
+ * scratch.
+ */
+ strbuf_reset(tmp);
+ strbuf_add(tmp, filename, dirlen - 1);
+ if (mkdir(tmp->buf, 0777) && errno != EEXIST)