From 474e4e8be21c493f230f90e913d54ab9191f8ffd Mon Sep 17 00:00:00 2001
From: drh <>
Date: Fri, 9 Aug 2024 13:56:12 +0000
Subject: [PATCH] Add SQLITE_TESTCTRL_EDITSTMT for making rogue changes to the
 statement bytecode, to test the death-cursor error detection mechanism.

FossilOrigin-Name: 58ffd5d97e86693ba669268154e6a28ccedf029abcdd2964635bcd8e5aa37172
---
 manifest        | 18 +++++++++---------
 manifest.uuid   |  2 +-
 src/main.c      | 24 ++++++++++++++++++++++++
 src/sqlite.h.in |  1 +
 src/vdbe.h      |  1 +
 src/vdbeaux.c   | 14 ++++++++++++++
 6 files changed, 50 insertions(+), 10 deletions(-)

diff --git a/manifest b/manifest
index 11e5ff9003..990a34ee7e 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Change\sthe\snull-cursor\sin\sthe\sprevious\scheck-in\sinto\sa\sdeath-cursor.\s\sAny\naccess\sof\sthe\scursor\scauses\sthe\sprepared\sstatement\sto\sreturn\san\nSQLITE_INTERNAL\serror.\s\sWe'll\sneed\sto\sadd\sa\sway\sto\sedit\sthe\sbytecode\nusing\ssqlite3_test_control()\sin\sorder\sto\stest\sthe\sdeath-cursor\scode\spath.
-D 2024-08-09T02:10:28.266
+C Add\sSQLITE_TESTCTRL_EDITSTMT\sfor\smaking\srogue\schanges\sto\sthe\sstatement\nbytecode,\sto\stest\sthe\sdeath-cursor\serror\sdetection\smechanism.
+D 2024-08-09T13:56:12.251
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -723,7 +723,7 @@ F src/insert.c 8ff11e9e54c5fc1fe89707b3d41cf44ad2822f712bd3b5da68338ea42518847e
 F src/json.c 5b6a1d6015997b9ee848a32948720bdb26a0ef2de5a2127ebf7355ce66dbdc0d
 F src/legacy.c d7874bc885906868cd51e6c2156698f2754f02d9eee1bae2d687323c3ca8e5aa
 F src/loadext.c 7432c944ff197046d67a1207790a1b13eec4548c85a9457eb0896bb3641dfb36
-F src/main.c 8a59d297ec77e6b78550433bfccb95a1b26f2fb69aaaf233206e21579a1cfcc1
+F src/main.c 05a2f97a06082640c5000a1d4db0b45e98f602d225a56b17679c8d2c34b05080
 F src/malloc.c 410e570b30c26cc36e3372577df50f7a96ee3eed5b2b161c6b6b48773c650c5e
 F src/mem0.c 6a55ebe57c46ca1a7d98da93aaa07f99f1059645
 F src/mem1.c 3bb59158c38e05f6270e761a9f435bf19827a264c13d1631c58b84bdc96d73b2
@@ -762,7 +762,7 @@ F src/resolve.c 7e8d23ce7cdbfedf351a47e759f2722e8182ca10fd7580be43f4ce1f1a228145
 F src/rowset.c 8432130e6c344b3401a8874c3cb49fefe6873fec593294de077afea2dce5ec97
 F src/select.c 6a95a2bffa6c09584dea99db5a7ae10c813305c09c92920ffc54f6eae2ba399e
 F src/shell.c.in 94571558b0fb28c37a5cf6dbd6ea27285341023a28a8cb5795cd2768fab67704
-F src/sqlite.h.in 1ad9110150773c38ebababbad11b5cb361bcd3997676dec1c91ac5e0416a7b86
+F src/sqlite.h.in d0e60f5c383964321984ef64f282db65a294803f6d9cc8959f5016e076e08e1c
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h 3f046c04ea3595d6bfda99b781926b17e672fd6d27da2ba6d8d8fc39981dcb54
 F src/sqliteInt.h e3f3b3d80a666a7c5c85b4db102d41ca831c5624f0b3001814479d376f00c19d
@@ -832,10 +832,10 @@ F src/utf.c f23165685a67b4caf8ec08fb274cb3f319103decfb2a980b7cfd55d18dfa855e
 F src/util.c 5d1a0134cf4240648d1c6bb5cc8efaca0ea2b5d5c840985aec7e947271f04375
 F src/vacuum.c 604fcdaebe76f3497c855afcbf91b8fa5046b32de3045bab89cc008d68e40104
 F src/vdbe.c 60429733c423a695045ab2dfe3c9dbd97dfd8ea512cb83271fe64be30bc10ba6
-F src/vdbe.h c2549a215898a390de6669cfa32adba56f0d7e17ba5a7f7b14506d6fd5f0c36a
+F src/vdbe.h 2087847de3cf8d50120ac29b1d7ed0f8b0dc4fb3801c6a448df8120f37194d8d
 F src/vdbeInt.h 949669dfd8a41550d27dcb905b494f2ccde9a2e6c1b0b04daa1227e2e74c2b2c
 F src/vdbeapi.c 80235ac380e9467fec1cb0883354d841f2a771976e766995f7e0c77f845406df
-F src/vdbeaux.c 25d685cafe119ff890c94345e884ea558a6b5d823bfa52ba708eb8ff3c70aa71
+F src/vdbeaux.c 84b5e691ed6ea4af4ed8bb4206651288ad38e0e2378b9216aa45681dd96adae0
 F src/vdbeblob.c 13f9287b55b6356b4b1845410382d6bede203ceb29ef69388a4a3d007ffacbe5
 F src/vdbemem.c 831a244831eaa45335f9ae276b50a7a82ee10d8c46c2c72492d4eb8c98d94d89
 F src/vdbesort.c d0a3c7056c081703c8b6d91ad60f17da5e062a5c64bf568ed0fa1b5f4cae311f
@@ -2204,8 +2204,8 @@ F vsixtest/vsixtest.tcl 6195aba1f12a5e10efc2b8c0009532167be5e301abe5b31385638080
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 7f1617f7bf53cf96954541f73fb99622051f86be9c8ea4b8038b2aa7c8f49e47
-R 9d7521711c8f264e36139e5c04db6efb
+P 8894b243ef533cd3d85afa3f3884e52df8c21ddd6cbb20716389a2ce28f130ab
+R 4cfcb7c3940a4d87692af3d2d3ac5b01
 U drh
-Z 62ed1b9b7427fb778a08fcfe7becb4f3
+Z c7a3fc75d5a79189317ebfd3f320fe9e
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index dabc6dcee2..5393f2b7b7 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-8894b243ef533cd3d85afa3f3884e52df8c21ddd6cbb20716389a2ce28f130ab
+58ffd5d97e86693ba669268154e6a28ccedf029abcdd2964635bcd8e5aa37172
diff --git a/src/main.c b/src/main.c
index bff801a87d..ba7a253245 100644
--- a/src/main.c
+++ b/src/main.c
@@ -4693,6 +4693,30 @@ int sqlite3_test_control(int op, ...){
 #endif
       break;
     }
+
+    /* sqlite3_test_control(SQLITE_TESTCTRL_EDITSTMT, pStmt,iAddr,iField,iVal)
+    **
+    ** Make changes to the bytecode in prepared statement pStmt.  Modify
+    ** instruction iAddr.  iField is 1, 2, or 3 for p1, p2, or p3.  iVal
+    ** is the new value.
+    **
+    ** This operation is used to deliberately corrupt bytecode in order to
+    ** exercise the internal self-checks that prevent crashes due to bugs in
+    ** the query planner and/or code generator.
+    */
+    case SQLITE_TESTCTRL_EDITSTMT: {
+      sqlite3_stmt *p;   /* The prepared statement */
+      int iAddr;         /* Instruction to change */
+      int iField;        /* 1, 2, or 3 for P1, P2, or P3 */
+      int iVal;          /* New value */
+
+      p = va_arg(ap, sqlite3_stmt*);
+      iAddr = va_arg(ap, int);
+      iField = va_arg(ap, int);
+      iVal = va_arg(ap, int);
+      sqlite3VdbeEditStmt(p,iAddr,iField,iVal);
+      break;
+    }
   }
   va_end(ap);
 #endif /* SQLITE_UNTESTABLE */
diff --git a/src/sqlite.h.in b/src/sqlite.h.in
index 027c0e62d4..48583f7f5f 100644
--- a/src/sqlite.h.in
+++ b/src/sqlite.h.in
@@ -8330,6 +8330,7 @@ int sqlite3_test_control(int op, ...);
 #define SQLITE_TESTCTRL_JSON_SELFCHECK          14
 #define SQLITE_TESTCTRL_OPTIMIZATIONS           15
 #define SQLITE_TESTCTRL_ISKEYWORD               16  /* NOT USED */
+#define SQLITE_TESTCTRL_EDITSTMT                16
 #define SQLITE_TESTCTRL_SCRATCHMALLOC           17  /* NOT USED */
 #define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS      17
 #define SQLITE_TESTCTRL_LOCALTIME_FAULT         18
diff --git a/src/vdbe.h b/src/vdbe.h
index f40f68d24b..b4216cc836 100644
--- a/src/vdbe.h
+++ b/src/vdbe.h
@@ -266,6 +266,7 @@ void sqlite3VdbeSetP4KeyInfo(Parse*, Index*);
 void sqlite3VdbeUsesBtree(Vdbe*, int);
 VdbeOp *sqlite3VdbeGetOp(Vdbe*, int);
 VdbeOp *sqlite3VdbeGetLastOp(Vdbe*);
+void sqlite3VdbeEditStmt(sqlite3_stmt*,int,int,int);
 int sqlite3VdbeMakeLabel(Parse*);
 void sqlite3VdbeRunOnlyOnce(Vdbe*);
 void sqlite3VdbeReusable(Vdbe*);
diff --git a/src/vdbeaux.c b/src/vdbeaux.c
index f1e0cccdc1..18d01f347e 100644
--- a/src/vdbeaux.c
+++ b/src/vdbeaux.c
@@ -1706,6 +1706,20 @@ VdbeOp *sqlite3VdbeGetLastOp(Vdbe *p){
   return sqlite3VdbeGetOp(p, p->nOp - 1);
 }
 
+/* Edit the bytecode of a runable prepared statement.  Used to implement
+** SQLITE_TESTCTRL_EDITSTMT.
+*/
+void sqlite3VdbeEditStmt(sqlite3_stmt *p, int iAddr, int iField, int iVal){
+  VdbeOp *pOp = &((Vdbe*)p)->aOp[iAddr];
+  if( iField==1 ){
+    pOp->p1 = iVal;
+  }else if( iField==2 ){
+    pOp->p2 = iVal;
+  }else{
+    pOp->p3 = iVal;
+  }
+}
+
 #if defined(SQLITE_ENABLE_EXPLAIN_COMMENTS)
 /*
 ** Return an integer value for one of the parameters to the opcode pOp
-- 
2.39.5