From: Matt Benjamin <mbenjamin@redhat.com>
Date: Sat, 27 Jan 2018 21:27:45 +0000 (-0500)
Subject: rgw_file: avoid evaluating nullptr for readdir offset
X-Git-Tag: v13.0.2~348^2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=bae94c6869018f54b01cb109f96e4062394be69d;p=ceph.git

rgw_file: avoid evaluating nullptr for readdir offset

I've found by experimentation that passing a null pointer
as a value to a CachedPrebufferedStreambuf ostream caused
subsequent log prints to be squelched.

(That's likely a bug, doesn't happen when the thread_local
optimization change is reverted.)

Fixes: https://tracker.ceph.com/issues/22820

Signed-off-by: Matt Benjamin <mbenjamin@redhat.com>
---

diff --git a/src/rgw/rgw_file.cc b/src/rgw/rgw_file.cc
index e6f16ec3706f..68dd18ec3816 100644
--- a/src/rgw/rgw_file.cc
+++ b/src/rgw/rgw_file.cc
@@ -1939,7 +1939,7 @@ int rgw_readdir2(struct rgw_fs *rgw_fs,
 
   lsubdout(parent->get_fs()->get_context(), rgw, 15)
     << __func__
-    << " offset=" << name
+    << " offset=" << ((name) ? name : "(nil)")
     << dendl;
 
   if ((! name) &&
diff --git a/src/rgw/rgw_file.h b/src/rgw/rgw_file.h
index d4e5333e0100..ec19898ae25a 100644
--- a/src/rgw/rgw_file.h
+++ b/src/rgw/rgw_file.h
@@ -1337,9 +1337,15 @@ public:
   }
 
   bool eof() {
-    lsubdout(cct, rgw, 15) << "READDIR offset: " << offset
-			   << " is_truncated: " << is_truncated
-			   << dendl;
+    if (unlikely(cct->_conf->subsys.should_gather(ceph_subsys_rgw, 15))) {
+      bool is_offset =
+	unlikely(! get<const char*>(&offset)) ||
+	!! get<const char*>(offset);
+      lsubdout(cct, rgw, 15) << "READDIR offset: " <<
+	((is_offset) ? offset : "(nil)")
+			     << " is_truncated: " << is_truncated
+			     << dendl;
+    }
     return !is_truncated;
   }
 
@@ -1526,10 +1532,16 @@ public:
   }
 
   bool eof() {
-    lsubdout(cct, rgw, 15) << "READDIR offset: " << offset
-			   << " next marker: " << next_marker
-			   << " is_truncated: " << is_truncated
-			   << dendl;
+    if (unlikely(cct->_conf->subsys.should_gather(ceph_subsys_rgw, 15))) {
+      bool is_offset =
+	unlikely(! get<const char*>(&offset)) ||
+	!! get<const char*>(offset);
+      lsubdout(cct, rgw, 15) << "READDIR offset: " <<
+	((is_offset) ? offset : "(nil)")
+			     << " next marker: " << next_marker
+			     << " is_truncated: " << is_truncated
+			     << dendl;
+    }
     return !is_truncated;
   }