From: drh <drh@noemail.net>
Date: Thu, 7 Apr 2016 18:42:23 +0000 (+0000)
Subject: Prevent the in-memory journal read cursor from entering an inconsistent state
X-Git-Tag: version-3.13.0~118
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=38b3dde00e766eb3e121b947c5c2c527d329503c;p=thirdparty%2Fsqlite.git

Prevent the in-memory journal read cursor from entering an inconsistent state
when it reads the last few bytes out of the journal file.  Fix for
ticket [7f7f8026eda38].

FossilOrigin-Name: c4b9c611bdcd85f31d68aaf114ee34a9f27eba6d
---

diff --git a/manifest b/manifest
index 54bbc7ace8..56e23c1277 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Avoid\sdecrementing\sa\spointer\soff\sthe\sfront\send\sof\sthe\sbuffer\sin\sOP_MakeRecord.
-D 2016-04-07T14:16:16.723
+C Prevent\sthe\sin-memory\sjournal\sread\scursor\sfrom\sentering\san\sinconsistent\sstate\nwhen\sit\sreads\sthe\slast\sfew\sbytes\sout\sof\sthe\sjournal\sfile.\s\sFix\sfor\nticket\s[7f7f8026eda38].
+D 2016-04-07T18:42:23.186
 F Makefile.in eba680121821b8a60940a81454316f47a341487a
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc 1f123a0757f6f04f0341accb46457e116817159a
@@ -347,7 +347,7 @@ F src/mem1.c 6919bcf12f221868ea066eec27e579fed95ce98b
 F src/mem2.c f1940d9e91948dd6a908fbb9ce3835c36b5d83c3
 F src/mem3.c 8768ac94694f31ffaf8b4d0ea5dc08af7010a35a
 F src/mem5.c 9bf955937b07f8c32541c8a9991f33ce3173d944
-F src/memjournal.c 5253fd4335a8d9c64e5df25cb9da6329af5242c7
+F src/memjournal.c 2815ef7684671d93a1ec6a31e1e63c45de4b4d31
 F src/msvc.h d9ba56c6851227ab44b3f228a35f3f5772296495
 F src/mutex.c 8e45800ee78e0cd1f1f3fe8e398853307f4a085c
 F src/mutex.h 779d588e3b7756ec3ecf7d78cde1d84aba414f85
@@ -1482,7 +1482,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 8415d4848ab36ca33b23d1fad6b063544de04a3b
-R 03453ebf1870335c86f4514ee1d5c7ac
+P 153135bfb3b8f7c407ccf36571e2d4d5afe28ea3
+R 79f1b101d10963168c95e54e3a571e58
 U drh
-Z 0a2d3c19f1c3d2a6467caf636e91907c
+Z fee1386714e022b25f3a73738d6ccce7
diff --git a/manifest.uuid b/manifest.uuid
index b3cd228a8b..c077c241b6 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-153135bfb3b8f7c407ccf36571e2d4d5afe28ea3
\ No newline at end of file
+c4b9c611bdcd85f31d68aaf114ee34a9f27eba6d
\ No newline at end of file
diff --git a/src/memjournal.c b/src/memjournal.c
index 4f0efc174e..fbfa7cb802 100644
--- a/src/memjournal.c
+++ b/src/memjournal.c
@@ -94,6 +94,7 @@ static int memjrnlRead(
 #endif
 
   assert( (iAmt+iOfst)<=p->endpoint.iOffset );
+  assert( p->readpoint.iOffset==0 || p->readpoint.pChunk!=0 );
   if( p->readpoint.iOffset!=iOfst || iOfst==0 ){
     sqlite3_int64 iOff = 0;
     for(pChunk=p->pFirst; 
@@ -104,6 +105,7 @@ static int memjrnlRead(
     }
   }else{
     pChunk = p->readpoint.pChunk;
+    assert( pChunk!=0 );
   }
 
   iChunkOffset = (int)(iOfst%p->nChunkSize);
@@ -115,7 +117,7 @@ static int memjrnlRead(
     nRead -= iSpace;
     iChunkOffset = 0;
   } while( nRead>=0 && (pChunk=pChunk->pNext)!=0 && nRead>0 );
-  p->readpoint.iOffset = iOfst+iAmt;
+  p->readpoint.iOffset = pChunk ? iOfst+iAmt : 0;
   p->readpoint.pChunk = pChunk;
 
   return SQLITE_OK;