+
+int read_pack_header(int fd, struct pack_header *header)
+{
+ char *c = (char*)header;
+ ssize_t remaining = sizeof(struct pack_header);
+ do {
+ ssize_t r = xread(fd, c, remaining);
+ if (r <= 0)
+ /* "eof before pack header was fully read" */
+ return PH_ERROR_EOF;
+ remaining -= r;
+ c += r;
+ } while (remaining > 0);
+ if (header->hdr_signature != htonl(PACK_SIGNATURE))
+ /* "protocol error (pack signature mismatch detected)" */
+ return PH_ERROR_PACK_SIGNATURE;
+ if (!pack_version_ok(header->hdr_version))
+ /* "protocol error (pack version unsupported)" */
+ return PH_ERROR_PROTOCOL;
+ return 0;
+}