HostResolverImpl: don't interpret NULL callback argument as a request to do synchronous resolution.

BUG=90547,60149
TEST=net_unittests

Review URL: http://codereview.chromium.org/7520026

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@94552 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 25 insertions, 24 deletions

diff --git a/net/base/host_resolver_impl.cc b/net/base/host_resolver_impl.cc
index af7d0d3..b317ca0 100644
--- a/net/base/host_resolver_impl.cc
+++ b/net/base/host_resolver_impl.cc
@@ -44,6 +44,10 @@ namespace net {
 
 namespace {
 
+// Limit the size of hostnames that will be resolved to combat issues in
+// some platform's resolvers.
+const size_t kMaxHostLength = 4096;
+
 // Helper to mutate the linked list contained by AddressList to the given
 // port. Note that in general this is dangerous since the AddressList's
 // data might be shared (and you should use AddressList::SetPort).
@@ -1143,6 +1147,19 @@ int HostResolverImpl::Resolve(const RequestInfo& info,
   // Update the net log and notify registered observers.
   OnStartRequest(source_net_log, request_net_log, request_id, info);
 
+  // The result of |getaddrinfo| for empty hosts is inconsistent across systems.
+  // On Windows it gives the default interface's address, whereas on Linux it
+  // gives an error. We will make it fail on all platforms for consistency.
+  if (info.hostname().empty() || info.hostname().size() > kMaxHostLength) {
+    OnFinishRequest(source_net_log,
+                    request_net_log,
+                    request_id,
+                    info,
+                    ERR_NAME_NOT_RESOLVED,
+                    0);
+    return ERR_NAME_NOT_RESOLVED;
+  }
+
   // Build a key that identifies the request in the cache and in the
   // outstanding jobs map.
   Key key = GetEffectiveKeyForRequest(info);
@@ -1170,6 +1187,13 @@ int HostResolverImpl::Resolve(const RequestInfo& info,
     return net_error;
   }
 
+  // Sanity check -- it shouldn't be the case that allow_cached_response is
+  // false while only_use_cached_response is true.
+  DCHECK(info.allow_cached_response() || !info.only_use_cached_response());
+
+  // If callback is NULL, we must be doing cache-only lookup.
+  DCHECK(callback || info.only_use_cached_response());
+
   // If we have an unexpired cache entry, use it.
   if (info.allow_cached_response() && cache_.get()) {
     const HostCache::Entry* cache_entry = cache_->Lookup(
@@ -1201,30 +1225,7 @@ int HostResolverImpl::Resolve(const RequestInfo& info,
     return ERR_NAME_NOT_RESOLVED;
   }
 
-  // If no callback was specified, do a synchronous resolution.
-  if (!callback) {
-    AddressList addrlist;
-    int os_error = 0;
-    int error = ResolveAddrInfo(
-        effective_resolver_proc(), key.hostname, key.address_family,
-        key.host_resolver_flags, &addrlist, &os_error);
-    if (error == OK) {
-      MutableSetPort(info.port(), &addrlist);
-      *addresses = addrlist;
-    }
-
-    // Write to cache.
-    if (cache_.get())
-      cache_->Set(key, error, addrlist, base::TimeTicks::Now());
-
-    // Update the net log and notify registered observers.
-    OnFinishRequest(source_net_log, request_net_log, request_id, info, error,
-                    os_error);
-
-    return error;
-  }
-
-  // Create a handle for this request, and pass it back to the user if they
+   // Create a handle for this request, and pass it back to the user if they
   // asked for it (out_req != NULL).
   Request* req = new Request(source_net_log, request_net_log, request_id, info,
                              callback, addresses);