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Unless the "--freelist-corrupt" option is specified, do not have the .recover command attempt to recover data from pages that are on the database free-list.

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FossilOrigin-Name: 8d2f52bb640d6d0f84b18d746043e56f45a73ace93239be1d036701f7f4018fd
This commit is contained in:
dan
2019-04-25 19:23:15 +00:00
parent b9b71dbfd4
commit 9c014f8b0c
3 changed files with 84 additions and 8 deletions
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78
src/shell.c.in
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@@ -3934,6 +3934,35 @@ readHexDb_error:
}
#endif /* SQLITE_ENABLE_DESERIALIZE */
/*
** Scalar function "shell_int32". The first argument to this function
** must be a blob. The second a non-negative integer. This function
** reads and returns a 32-bit big-endian integer from byte
** offset (4*<arg2>) of the blob.
*/
static void shellInt32(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
const unsigned char *pBlob;
int nBlob;
int iInt;
nBlob = sqlite3_value_bytes(argv[0]);
pBlob = (const unsigned char*)sqlite3_value_blob(argv[0]);
iInt = sqlite3_value_int(argv[1]);
if( iInt>=0 && (iInt+1)*4<=nBlob ){
const unsigned char *a = &pBlob[iInt*4];
sqlite3_int64 iVal = ((sqlite3_int64)a[0]<<24)
+ ((sqlite3_int64)a[1]<<16)
+ ((sqlite3_int64)a[2]<< 8)
+ ((sqlite3_int64)a[3]<< 0);
sqlite3_result_int64(context, iVal);
}
}
/*
** Scalar function "shell_escape_crnl" used by the .recover command.
** The argument passed to this function is the output of built-in
@@ -4105,6 +4134,8 @@ static void open_db(ShellState *p, int openFlags){
shellPutsFunc, 0, 0);
sqlite3_create_function(p->db, "shell_escape_crnl", 1, SQLITE_UTF8, 0,
shellEscapeCrnl, 0, 0);
sqlite3_create_function(p->db, "shell_int32", 2, SQLITE_UTF8, 0,
shellInt32, 0, 0);
#ifndef SQLITE_NOHAVE_SYSTEM
sqlite3_create_function(p->db, "edit", 1, SQLITE_UTF8, 0,
editFunc, 0, 0);
@@ -6374,6 +6405,25 @@ static int recoverDatabaseCmd(ShellState *pState, int nArg, char **azArg){
sqlite3_stmt *pLoop = 0; /* Loop through all root pages */
sqlite3_stmt *pPages = 0; /* Loop through all pages in a group */
sqlite3_stmt *pCells = 0; /* Loop through all cells in a page */
int i;
int bFreelist = 1; /* 0 if --freelist-corrupt is specified */
for(i=1; i<nArg; i++){
char *z = azArg[i];
int n;
if( z[0]=='-' && z[1]=='-' ) z++;
n = strlen(z);
if( n<=17 && memcmp("-freelist-corrupt", z, n)==0 ){
bFreelist = 0;
}
else{
raw_printf(stderr,
"unexpected option: %s - expected \"--freelist-corrupt\"\n",
azArg[i]
);
return 1;
}
}
shellExec(pState->db, &rc,
/* Attach an in-memory database named 'recovery'. Create an indexed
@@ -6395,6 +6445,32 @@ static int recoverDatabaseCmd(ShellState *pState, int nArg, char **azArg){
" SELECT child FROM recovery.dbptr GROUP BY child HAVING count(*)>1"
");"
"CREATE TABLE recovery.freelist(pgno INTEGER PRIMARY KEY);"
);
if( bFreelist ){
shellExec(pState->db, &rc,
"WITH trunk(pgno) AS ("
" SELECT shell_int32("
" (SELECT data FROM sqlite_dbpage WHERE pgno=1), 8) AS x "
" WHERE x>0"
" UNION"
" SELECT shell_int32("
" (SELECT data FROM sqlite_dbpage WHERE pgno=trunk.pgno), 0) AS x "
" FROM trunk WHERE x>0"
"),"
"freelist(data, n, freepgno) AS ("
" SELECT data, shell_int32(data, 1)-1, t.pgno "
" FROM trunk t, sqlite_dbpage s WHERE s.pgno=t.pgno"
" UNION ALL"
" SELECT data, n-1, shell_int32(data, 2+n) "
" FROM freelist WHERE n>=0"
")"
"REPLACE INTO recovery.freelist SELECT freepgno FROM freelist;"
);
}
shellExec(pState->db, &rc,
/* Create the "map" table that will (eventually) contain instructions
** for dealing with each page in the db that contains one or more
** records. */
@@ -6424,7 +6500,7 @@ static int recoverDatabaseCmd(ShellState *pState, int nArg, char **azArg){
" )"
" SELECT pgno FROM p WHERE (parent IS NULL OR pgno = orig)"
") "
"FROM pages WHERE maxlen > 0;"
"FROM pages WHERE maxlen > 0 AND i NOT IN freelist;"
"UPDATE recovery.map AS o SET intkey = ("
" SELECT substr(data, 1, 1)==X'0D' FROM sqlite_dbpage WHERE pgno=o.pgno"
");"