Fixed handling of race condition.

diff --git a/src/client_side.cc b/src/client_side.cc
index a32cbaf294921fb390eb48709d288c4a5b72705d..5e8f4bd0d79631aa1d18ab2ce0a570fd211d81eb 100644 (file)
--- a/src/client_side.cc
+++ b/src/client_side.cc
@@ -1,6 +1,6 @@
 
 /*
- * $Id: client_side.cc,v 1.35 1996/09/20 06:28:30 wessels Exp $
+ * $Id: client_side.cc,v 1.36 1996/09/23 22:13:05 wessels Exp $
  *
  * DEBUG: section 33    Client-side Routines
  * AUTHOR: Duane Wessels
@@ -395,6 +395,7 @@ icpHandleIMSReply(int fd, StoreEntry * entry, void *data)
     char *hbuf;
     int len;
     int unlink_request = 0;
+    StoreEntry *oldentry;
     debug(33, 3, "icpHandleIMSReply: FD %d '%s'\n", fd, entry->url);
     /* unregister this handler */
     storeUnregister(entry, fd);
@@ -418,25 +419,34 @@ icpHandleIMSReply(int fd, StoreEntry * entry, void *data)
        return 0;
     }
     if (mem->reply->code == 304 && !BIT_TEST(icpState->request->flags, REQ_IMS)) {
-       icpState->log_type = LOG_TCP_EXPIRED_HIT;
        /* We initiated the IMS request, the client is not expecting
-        * 304, so put the good one back */
-       if (icpState->old_entry->mem_obj->request == NULL) {
-           icpState->old_entry->mem_obj->request = requestLink(mem->request);
+        * 304, so put the good one back.  First, make sure the old entry
+        * headers have been loaded from disk. */
+       oldentry = icpState->old_entry;
+       if (oldentry->mem_obj->e_current_len == 0) {
+           storeRegister(entry,
+               fd,
+               (PIF) icpHandleIMSReply,
+               (void *) icpState);
+           return 0;
+       }
+       icpState->log_type = LOG_TCP_EXPIRED_HIT;
+       hbuf = get_free_8k_page();
+       storeClientCopy(oldentry, 0, 8191, hbuf, &len, fd);
+       if (oldentry->mem_obj->request == NULL) {
+           oldentry->mem_obj->request = requestLink(mem->request);
            unlink_request = 1;
        }
        storeUnlockObject(entry);
-       entry = icpState->entry = icpState->old_entry;
-       /* Extend the TTL
-        * XXX race condition here.  Assumes old_entry has been swapped 
-        * in by the time this 304 reply arrives.  */
-       hbuf = get_free_8k_page();
-       storeClientCopy(entry, 0, 8191, hbuf, &len, fd);
-       if (!mime_headers_end(hbuf))
-           fatal_dump("icpHandleIMSReply: failed to load headers, lost race");
-       httpParseHeaders(hbuf, entry->mem_obj->reply);
+       entry = icpState->entry = oldentry;
+       if (mime_headers_end(hbuf)) {
+           httpParseHeaders(hbuf, entry->mem_obj->reply);
+           ttlSet(entry);
+       } else {
+           debug(33,1,"icpHandleIMSReply: No end-of-headers, len=%d\n", len);
+           debug(33,1,"  --> '%s'\n", entry->url);
+       }
        put_free_8k_page(hbuf);
-       ttlSet(entry);
        if (unlink_request) {
            requestUnlink(entry->mem_obj->request);
            entry->mem_obj->request = NULL;