Ensure that "PRAGMA integrity_check" reports an error if the free-list count header field contains a value smaller than the actual number of pages on the database free-list.

FossilOrigin-Name: 26f64986d1ed59c554a7cb9e00e86a7f148f1fc6

manifest

@@ -1,5 +1,5 @@
-C Fix\sthe\sorderby9.test\scase\sso\sthat\sit\sworks\swith\s32-bit\sversions\sof\sTCL
+C Ensure\sthat\s"PRAGMA\sintegrity_check"\sreports\san\serror\sif\sthe\sfree-list\scount\sheader\sfield\scontains\sa\svalue\ssmaller\sthan\sthe\sactual\snumber\sof\spages\son\sthe\sdatabase\sfree-list.
-D 2015-09-18T14:42:48.399
+D 2015-09-18T14:45:01.549
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in f85066ce844a28b671aaeeff320921cd0ce36239
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -282,7 +282,7 @@ F src/auth.c b56c78ebe40a2110fd361379f7e8162d23f92240
 F src/backup.c 4d9134dc988a87838c06056c89c0e8c4700a0452
 F src/bitvec.c d1f21d7d91690747881f03940584f4cc548c9d3d
 F src/btmutex.c 45a968cc85afed9b5e6cf55bf1f42f8d18107f79
-F src/btree.c d31008cfbf83e3ae5cb96bae3a00f4b57f244a16
+F src/btree.c 0dc030ce71f62d6ec8305c660b432d8b4a7f2ae5
 F src/btree.h 40189aefdc2b830d25c8b58fd7d56538481bfdd7
 F src/btreeInt.h 8177c9ab90d772d6d2c6c517e05bed774b7c92c0
 F src/build.c 8a86f4203ac8a9ac0734f242a96f043edffb6018
@@ -531,7 +531,7 @@ F test/conflict2.test 0d3af4fb534fa1bd020c79960bb56e4d52655f09
 F test/conflict3.test dec0634c0f31dec9a4b01c63063e939f0cd21b6b
 F test/contrib01.test 2a1cbc0f2f48955d7d073f725765da6fbceda6b4
 F test/corrupt.test 141c39ea650c1365e85a49e402fa05cb9617fb97
-F test/corrupt2.test 08cec1e5ffa68a3610306d6068f112d08bc9f090
+F test/corrupt2.test cb787825d761b0f869764d6990531382840de872
 F test/corrupt3.test 4b548d0bbe2933bc81d3f54099a05fc4d28aff18
 F test/corrupt4.test b99652079d542b21f4965f6248703b983e40fe80
 F test/corrupt5.test 8ead52af76006f3286e9396cb41898018ccea107
@@ -1387,7 +1387,7 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh 48bd54594752d5be3337f12c72f28d2080cb630b
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P c88b62c28cc7ac31b93f7df0c732e0bb6ca24f65
+P 4b6af7743034546a407a3e4722645945a4efc8a1
-R d7ae7141144938bfc8bce5fb809aed89
+R 8f617f75843755643117296bdc790a84
-U drh
+U dan
-Z 2e0d2113b5f408a0d1fc7870da6f8192
+Z 7ed8e4f96741fa0762b4a1c2e770ca35

manifest.uuid

@@ -1 +1 @@
-4b6af7743034546a407a3e4722645945a4efc8a1
+26f64986d1ed59c554a7cb9e00e86a7f148f1fc6

src/btree.c

@@ -8921,6 +8921,10 @@ static void checkList(
 #endif
     iPage = get4byte(pOvflData);
     sqlite3PagerUnref(pOvflPage);
+
+    if( isFreeList && N<(iPage!=0) ){
+      checkAppendMsg(pCheck, "free-page count in header is too small");
+    }
   }
 }
 #endif /* SQLITE_OMIT_INTEGRITY_CHECK */

test/corrupt2.test

@@ -17,6 +17,7 @@
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
+set testprefix corrupt2
 
 # Do not use a codec for tests in this file, as the database file is
 # manipulated directly using tcl scripts (using the [hexio_write] command).
@@ -558,4 +559,51 @@ ifcapable autovacuum {
   }
 }
 
+#-------------------------------------------------------------------------
+# Test that PRAGMA integrity_check detects cases where the freelist-count
+# header field is smaller than the actual number of pages on the freelist.
+#
+
+reset_db
+do_execsql_test 14.0 {
+  PRAGMA auto_vacuum = 0;
+  CREATE TABLE t1(x);
+  INSERT INTO t1 VALUES(randomblob(3500));
+  DELETE FROM t1;
+}
+
+do_execsql_test 14.1 {
+  PRAGMA integrity_check;
+  PRAGMA freelist_count;
+} {ok 3}
+
+# There are now 3 free pages. Modify the header-field so that it 
+# (incorrectly) says that just 2 are free.
+do_test 14.2 {
+  db close
+  hexio_write test.db 36 [hexio_render_int32 2]
+  sqlite3 db test.db
+  execsql { PRAGMA freelist_count }
+} {2}
+
+do_execsql_test 14.3 {
+  PRAGMA integrity_check;
+} {{*** in database main ***
+Main freelist: free-page count in header is too small}}
+
+# Use 2 of the free pages on the free-list.
+#
+do_execsql_test 14.4 {
+  INSERT INTO t1 VALUES(randomblob(2500));
+  PRAGMA freelist_count;
+} {0}
+
+do_execsql_test 14.5 {
+  PRAGMA integrity_check;
+} {{*** in database main ***
+Page 3 is never used}}
+
+
+finish_test
+
 finish_test