mirrors/sqlite
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
80b1f6fcde
sqlite/ext/recover/sqlite3recover.c
dan 80b1f6fcde Fix various compiler warnings in new code on this branch. 
FossilOrigin-Name: ae49e9efde3012158061def6e0a8d993abbc5933514a21f84bc10f700f61b5e2
2022-09-23 11:40:43 +00:00

1850 lines
56 KiB
C
Raw Blame History

/*
** 2022-08-27
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
*************************************************************************
**
*/
#include "sqlite3recover.h"
#include <assert.h>
#include <string.h>
/*
** Declaration for public API function in file dbdata.c. This may be called
** with NULL as the final two arguments to register the sqlite_dbptr and
** sqlite_dbdata virtual tables with a database handle.
*/
#ifdef _WIN32
__declspec(dllexport)
#endif
int sqlite3_dbdata_init(sqlite3*, char**, const sqlite3_api_routines*);
typedef unsigned int u32;
typedef sqlite3_int64 i64;
typedef struct RecoverTable RecoverTable;
typedef struct RecoverColumn RecoverColumn;
/*
** When recovering rows of data that can be associated with table
** definitions recovered from the sqlite_schema table, each table is
** represented by an instance of the following object.
**
** iRoot:
** The root page in the original database. Not necessarily (and usually
** not) the same in the recovered database.
**
** zTab:
** Name of the table.
**
** nCol/aCol[]:
** aCol[] is an array of nCol columns. In the order in which they appear
** in the table.
**
** bIntkey:
** Set to true for intkey tables, false for WITHOUT ROWID.
**
** iRowidBind:
** Each column in the aCol[] array has associated with it the index of
** the bind parameter its values will be bound to in the INSERT statement
** used to construct the output database. If the table does has a rowid
** but not an INTEGER PRIMARY KEY column, then iRowidBind contains the
** index of the bind paramater to which the rowid value should be bound.
** Otherwise, it contains -1. If the table does contain an INTEGER PRIMARY
** KEY column, then the rowid value should be bound to the index associated
** with the column.
**
** pNext:
** All RecoverTable objects used by the recovery operation are allocated
** and populated as part of creating the recovered database schema in
** the output database, before any non-schema data are recovered. They
** are then stored in a singly-linked list linked by this variable beginning
** at sqlite3_recover.pTblList.
*/
struct RecoverTable {
u32 iRoot; /* Root page in original database */
char *zTab; /* Name of table */
int nCol; /* Number of columns in table */
RecoverColumn *aCol; /* Array of columns */
int bIntkey; /* True for intkey, false for without rowid */
int iRowidBind; /* If >0, bind rowid to INSERT here */
RecoverTable *pNext;
};
/*
** Each database column is represented by an instance of the following object
** stored in the RecoverTable.aCol[] array of the associated table.
**
** iField:
** The index of the associated field within database records. Or -1 if
** there is no associated field (e.g. for virtual generated columns).
**
** iBind:
** The bind index of the INSERT statement to bind this columns values
** to. Or 0 if there is no such index (iff (iField<0)).
**
** bIPK:
** True if this is the INTEGER PRIMARY KEY column.
**
** zCol:
** Name of column.
**
** eHidden:
** A RECOVER_EHIDDEN_* constant value (see below for interpretation of each).
*/
struct RecoverColumn {
int iField; /* Field in record on disk */
int iBind; /* Binding to use in INSERT */
int bIPK; /* True for IPK column */
char *zCol;
int eHidden;
};
#define RECOVER_EHIDDEN_NONE 0 /* Normal database column */
#define RECOVER_EHIDDEN_HIDDEN 1 /* Column is __HIDDEN__ */
#define RECOVER_EHIDDEN_VIRTUAL 2 /* Virtual generated column */
#define RECOVER_EHIDDEN_STORED 3 /* Stored generated column */
/*
** Bitmap object used to track pages in the input database. Allocated
** and manipulated only by the following functions:
**
** recoverBitmapAlloc()
** recoverBitmapFree()
** recoverBitmapSet()
** recoverBitmapQuery()
**
** nPg:
** Largest page number that may be stored in the bitmap. The range
** of valid keys is 1 to nPg, inclusive.
**
** aElem[]:
** Array large enough to contain a bit for each key. For key value
** iKey, the associated bit is the bit (iKey%32) of aElem[iKey/32].
** In other words, the following is true if bit iKey is set, or
** false if it is clear:
**
** (aElem[iKey/32] & (1 << (iKey%32))) ? 1 : 0
*/
typedef struct RecoverBitmap RecoverBitmap;
struct RecoverBitmap {
i64 nPg; /* Size of bitmap */
u32 aElem[1]; /* Array of 32-bit bitmasks */
};
/*
** Main recover handle structure.
*/
struct sqlite3_recover {
/* Copies of sqlite3_recover_init[_sql]() parameters */
sqlite3 *dbIn; /* Input database */
char *zDb; /* Name of input db ("main" etc.) */
char *zUri; /* URI for output database */
void *pSqlCtx; /* SQL callback context */
int (*xSql)(void*,const char*); /* Pointer to SQL callback function */
/* Values configured by sqlite3_recover_config() */
char *zStateDb; /* State database to use (or NULL) */
char *zLostAndFound; /* Name of lost-and-found table (or NULL) */
int bFreelistCorrupt; /* SQLITE_RECOVER_FREELIST_CORRUPT setting */
int bRecoverRowid; /* SQLITE_RECOVER_ROWIDS setting */
/* Error code and error message */
int errCode; /* For sqlite3_recover_errcode() */
char *zErrMsg; /* For sqlite3_recover_errmsg() */
/* Fields used within sqlite3_recover_run() */
int bRun; /* True once _recover_run() has been called */
sqlite3 *dbOut; /* Output database */
sqlite3_stmt *pGetPage; /* SELECT against input db sqlite_dbdata */
RecoverTable *pTblList; /* List of tables recovered from schem */
RecoverBitmap *pUsed; /* Used by recoverLostAndFound() */
};
/*
** Default value for SQLITE_RECOVER_ROWIDS (sqlite3_recover.bRecoverRowid).
*/
#define RECOVER_ROWID_DEFAULT 1
/*
** Like strlen(). But handles NULL pointer arguments.
*/
static int recoverStrlen(const char *zStr){
int nRet = 0;
if( zStr ){
while( zStr[nRet] ) nRet++;
}
return nRet;
}
/*
** This function is a no-op if the recover handle passed as the first
** argument already contains an error (if p->errCode!=SQLITE_OK).
**
** Otherwise, an attempt is made to allocate, zero and return a buffer nByte
** bytes in size. If successful, a pointer to the new buffer is returned. Or,
** if an OOM error occurs, NULL is returned and the handle error code
** (p->errCode) set to SQLITE_NOMEM.
*/
static void *recoverMalloc(sqlite3_recover *p, i64 nByte){
void *pRet = 0;
assert( nByte>0 );
if( p->errCode==SQLITE_OK ){
pRet = sqlite3_malloc64(nByte);
if( pRet ){
memset(pRet, 0, nByte);
}else{
p->errCode = SQLITE_NOMEM;
}
}
return pRet;
}
/*
** Set the error code and error message for the recover handle passed as
** the first argument. The error code is set to the value of parameter
** errCode.
**
** Parameter zFmt must be a printf() style formatting string. The handle
** error message is set to the result of using any trailing arguments for
** parameter substitutions in the formatting string.
**
** For example:
**
** recoverError(p, SQLITE_ERROR, "no such table: %s", zTablename);
*/
static int recoverError(
sqlite3_recover *p,
int errCode,
const char *zFmt, ...
){
char *z = 0;
va_list ap;
va_start(ap, zFmt);
if( zFmt ){
z = sqlite3_vmprintf(zFmt, ap);
va_end(ap);
}
sqlite3_free(p->zErrMsg);
p->zErrMsg = z;
p->errCode = errCode;
return errCode;
}
/*
** This function is a no-op if p->errCode is initially other than SQLITE_OK.
** In this case it returns NULL.
**
** Otherwise, an attempt is made to allocate and return a bitmap object
** large enough to store a bit for all page numbers between 1 and nPg,
** inclusive. The bitmap is initially zeroed.
*/
static RecoverBitmap *recoverBitmapAlloc(sqlite3_recover *p, i64 nPg){
int nElem = (nPg+1+31) / 32;
int nByte = sizeof(RecoverBitmap) + nElem*sizeof(u32);
RecoverBitmap *pRet = (RecoverBitmap*)recoverMalloc(p, nByte);
if( pRet ){
pRet->nPg = nPg;
}
return pRet;
}
/*
** Free a bitmap object allocated by recoverBitmapAlloc().
*/
static void recoverBitmapFree(RecoverBitmap *pMap){
sqlite3_free(pMap);
}
/*
** Set the bit associated with page iPg in bitvec pMap.
*/
static void recoverBitmapSet(RecoverBitmap *pMap, i64 iPg){
if( iPg<=pMap->nPg ){
int iElem = (iPg / 32);
int iBit = (iPg % 32);
pMap->aElem[iElem] |= (((u32)1) << iBit);
}
}
/*
** Query bitmap object pMap for the state of the bit associated with page
** iPg. Return 1 if it is set, or 0 otherwise.
*/
static int recoverBitmapQuery(RecoverBitmap *pMap, i64 iPg){
int ret = 1;
if( iPg<=pMap->nPg ){
int iElem = (iPg / 32);
int iBit = (iPg % 32);
ret = (pMap->aElem[iElem] & (((u32)1) << iBit)) ? 1 : 0;
}
return ret;
}
/*
** Set the recover handle error to the error code and message returned by
** calling sqlite3_errcode() and sqlite3_errmsg(), respectively, on database
** handle db.
*/
static int recoverDbError(sqlite3_recover *p, sqlite3 *db){
return recoverError(p, sqlite3_errcode(db), "%s", sqlite3_errmsg(db));
}
/*
** This function is a no-op if recover handle p already contains an error
** (if p->errCode!=SQLITE_OK).
**
** Otherwise, it attempts to prepare the SQL statement in zSql against
** database handle db. If successful, the statement handle is returned.
** Or, if an error occurs, NULL is returned and an error left in the
** recover handle.
*/
static sqlite3_stmt *recoverPrepare(
sqlite3_recover *p,
sqlite3 *db,
const char *zSql
){
sqlite3_stmt *pStmt = 0;
if( p->errCode==SQLITE_OK ){
if( sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0) ){
recoverDbError(p, db);
}
}
return pStmt;
}
/*
** This function is a no-op if recover handle p already contains an error
** (if p->errCode!=SQLITE_OK).
**
** Otherwise, argument zFmt is used as a printf() style format string,
** along with any trailing arguments, to create an SQL statement. This
** SQL statement is prepared against database handle db and, if successful,
** the statment handle returned. Or, if an error occurs - either during
** the printf() formatting or when preparing the resulting SQL - an
** error code and message are left in the recover handle.
*/
static sqlite3_stmt *recoverPreparePrintf(
sqlite3_recover *p,
sqlite3 *db,
const char *zFmt, ...
){
sqlite3_stmt *pStmt = 0;
if( p->errCode==SQLITE_OK ){
va_list ap;
char *z;
va_start(ap, zFmt);
z = sqlite3_vmprintf(zFmt, ap);
va_end(ap);
if( z==0 ){
p->errCode = SQLITE_NOMEM;
}else{
pStmt = recoverPrepare(p, db, z);
sqlite3_free(z);
}
}
return pStmt;
}
/*
** Reset SQLite statement handle pStmt. If the call to sqlite3_reset()
** indicates that an error occurred, and there is not already an error
** in the recover handle passed as the first argument, set the error
** code and error message appropriately.
**
** This function returns a copy of the statement handle pointer passed
** as the second argument.
*/
static sqlite3_stmt *recoverReset(sqlite3_recover *p, sqlite3_stmt *pStmt){
int rc = sqlite3_reset(pStmt);
if( rc!=SQLITE_OK && p->errCode==SQLITE_OK ){
recoverDbError(p, sqlite3_db_handle(pStmt));
}
return pStmt;
}
/*
** Finalize SQLite statement handle pStmt. If the call to sqlite3_reset()
** indicates that an error occurred, and there is not already an error
** in the recover handle passed as the first argument, set the error
** code and error message appropriately.
*/
static void recoverFinalize(sqlite3_recover *p, sqlite3_stmt *pStmt){
sqlite3 *db = sqlite3_db_handle(pStmt);
int rc = sqlite3_finalize(pStmt);
if( rc!=SQLITE_OK && p->errCode==SQLITE_OK ){
recoverDbError(p, db);
}
}
/*
** This function is a no-op if recover handle p already contains an error
** (if p->errCode!=SQLITE_OK). A copy of p->errCode is returned in this
** case.
**
** Otherwise, execute SQL script zSql. If successful, return SQLITE_OK.
** Or, if an error occurs, leave an error code and message in the recover
** handle and return a copy of the error code.
*/
static int recoverExec(sqlite3_recover *p, sqlite3 *db, const char *zSql){
if( p->errCode==SQLITE_OK ){
int rc = sqlite3_exec(db, zSql, 0, 0, 0);
if( rc ){
recoverDbError(p, db);
}
}
return p->errCode;
}
/*
** Bind the value pVal to parameter iBind of statement pStmt. Leave an
** error in the recover handle passed as the first argument if an error
** (e.g. an OOM) occurs.
*/
static void recoverBindValue(
sqlite3_recover *p,
sqlite3_stmt *pStmt,
int iBind,
sqlite3_value *pVal
){
if( p->errCode==SQLITE_OK ){
int rc = sqlite3_bind_value(pStmt, iBind, pVal);
if( rc ) recoverError(p, rc, 0);
}
}
/*
** This function is a no-op if recover handle p already contains an error
** (if p->errCode!=SQLITE_OK). NULL is returned in this case.
**
** Otherwise, an attempt is made to interpret zFmt as a printf() style
** formatting string and the result of using the trailing arguments for
** parameter substitution with it written into a buffer obtained from
** sqlite3_malloc(). If successful, a pointer to the buffer is returned.
** It is the responsibility of the caller to eventually free the buffer
** using sqlite3_free().
**
** Or, if an error occurs, an error code and message is left in the recover
** handle and NULL returned.
*/
static char *recoverMPrintf(sqlite3_recover *p, const char *zFmt, ...){
va_list ap;
char *z;
va_start(ap, zFmt);
z = sqlite3_vmprintf(zFmt, ap);
va_end(ap);
if( p->errCode==SQLITE_OK ){
if( z==0 ) p->errCode = SQLITE_NOMEM;
}else{
sqlite3_free(z);
z = 0;
}
return z;
}
/*
** This function is a no-op if recover handle p already contains an error
** (if p->errCode!=SQLITE_OK). Zero is returned in this case.
**
** Otherwise, execute "PRAGMA page_count" against the input database. If
** successful, return the integer result. Or, if an error occurs, leave an
** error code and error message in the sqlite3_recover handle and return
** zero.
*/
static i64 recoverPageCount(sqlite3_recover *p){
i64 nPg = 0;
if( p->errCode==SQLITE_OK ){
sqlite3_stmt *pStmt = 0;
pStmt = recoverPreparePrintf(p, p->dbIn, "PRAGMA %Q.page_count", p->zDb);
if( pStmt ){
sqlite3_step(pStmt);
nPg = sqlite3_column_int64(pStmt, 0);
}
recoverFinalize(p, pStmt);
}
return nPg;
}
/*
** Implementation of SQL scalar function "read_i32". 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.
**
** SELECT read_i32(<blob>, <idx>)
*/
static void recoverReadI32(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
const unsigned char *pBlob;
int nBlob;
int iInt;
assert( argc==2 );
nBlob = sqlite3_value_bytes(argv[0]);
pBlob = (const unsigned char*)sqlite3_value_blob(argv[0]);
iInt = sqlite3_value_int(argv[1]) & 0xFFFF;
if( (iInt+1)*4<=nBlob ){
const unsigned char *a = &pBlob[iInt*4];
i64 iVal = ((i64)a[0]<<24)
+ ((i64)a[1]<<16)
+ ((i64)a[2]<< 8)
+ ((i64)a[3]<< 0);
sqlite3_result_int64(context, iVal);
}
}
/*
** Implementation of SQL scalar function "page_is_used". This function
** is used as part of the procedure for locating orphan rows for the
** lost-and-found table, and it depends on those routines having populated
** the sqlite3_recover.pUsed variable.
**
** The only argument to this function is a page-number. It returns true
** if the page has already been used somehow during data recovery, or false
** otherwise.
**
** SELECT page_is_used(<pgno>);
*/
static void recoverPageIsUsed(
sqlite3_context *pCtx,
int nArg,
sqlite3_value **apArg
){
sqlite3_recover *p = (sqlite3_recover*)sqlite3_user_data(pCtx);
i64 pgno = sqlite3_value_int64(apArg[0]);
assert( nArg==1 );
sqlite3_result_int(pCtx, recoverBitmapQuery(p->pUsed, pgno));
}
/*
** The implementation of a user-defined SQL function invoked by the
** sqlite_dbdata and sqlite_dbptr virtual table modules to access pages
** of the database being recovered.
**
** This function always takes a single integer argument. If the argument
** is zero, then the value returned is the number of pages in the db being
** recovered. If the argument is greater than zero, it is a page number.
** The value returned in this case is an SQL blob containing the data for
** the identified page of the db being recovered. e.g.
**
** SELECT getpage(0); -- return number of pages in db
** SELECT getpage(4); -- return page 4 of db as a blob of data
*/
static void recoverGetPage(
sqlite3_context *pCtx,
int nArg,
sqlite3_value **apArg
){
sqlite3_recover *p = (sqlite3_recover*)sqlite3_user_data(pCtx);
i64 pgno = sqlite3_value_int64(apArg[0]);
sqlite3_stmt *pStmt = 0;
assert( nArg==1 );
if( pgno==0 ){
i64 nPg = recoverPageCount(p);
sqlite3_result_int64(pCtx, nPg);
return;
}else{
if( p->pGetPage==0 ){
pStmt = p->pGetPage = recoverPreparePrintf(
p, p->dbIn, "SELECT data FROM sqlite_dbpage(%Q) WHERE pgno=?", p->zDb
);
}else{
pStmt = p->pGetPage;
}
if( pStmt ){
sqlite3_bind_int64(pStmt, 1, pgno);
if( SQLITE_ROW==sqlite3_step(pStmt) ){
sqlite3_result_value(pCtx, sqlite3_column_value(pStmt, 0));
}
recoverReset(p, pStmt);
}
}
if( p->errCode ){
if( p->zErrMsg ) sqlite3_result_error(pCtx, p->zErrMsg, -1);
sqlite3_result_error_code(pCtx, p->errCode);
}
}
/*
** Find a string that is not found anywhere in z[]. Return a pointer
** to that string.
**
** Try to use zA and zB first. If both of those are already found in z[]
** then make up some string and store it in the buffer zBuf.
*/
static const char *recoverUnusedString(
const char *z, /* Result must not appear anywhere in z */
const char *zA, const char *zB, /* Try these first */
char *zBuf /* Space to store a generated string */
){
unsigned i = 0;
if( strstr(z, zA)==0 ) return zA;
if( strstr(z, zB)==0 ) return zB;
do{
sqlite3_snprintf(20,zBuf,"(%s%u)", zA, i++);
}while( strstr(z,zBuf)!=0 );
return zBuf;
}
/*
** Implementation of scalar SQL function "escape_crnl". The argument passed to
** this function is the output of built-in function quote(). If the first
** character of the input is "'", indicating that the value passed to quote()
** was a text value, then this function searches the input for "\n" and "\r"
** characters and adds a wrapper similar to the following:
**
** replace(replace(<input>, '\n', char(10), '\r', char(13));
**
** Or, if the first character of the input is not "'", then a copy of the input
** is returned.
*/
static void recoverEscapeCrnl(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
const char *zText = (const char*)sqlite3_value_text(argv[0]);
if( zText && zText[0]=='\'' ){
int nText = sqlite3_value_bytes(argv[0]);
int i;
char zBuf1[20];
char zBuf2[20];
const char *zNL = 0;
const char *zCR = 0;
int nCR = 0;
int nNL = 0;
for(i=0; zText[i]; i++){
if( zNL==0 && zText[i]=='\n' ){
zNL = recoverUnusedString(zText, "\\n", "\\012", zBuf1);
nNL = (int)strlen(zNL);
}
if( zCR==0 && zText[i]=='\r' ){
zCR = recoverUnusedString(zText, "\\r", "\\015", zBuf2);
nCR = (int)strlen(zCR);
}
}
if( zNL || zCR ){
int iOut = 0;
i64 nMax = (nNL > nCR) ? nNL : nCR;
i64 nAlloc = nMax * nText + (nMax+64)*2;
char *zOut = (char*)sqlite3_malloc64(nAlloc);
if( zOut==0 ){
sqlite3_result_error_nomem(context);
return;
}
if( zNL && zCR ){
memcpy(&zOut[iOut], "replace(replace(", 16);
iOut += 16;
}else{
memcpy(&zOut[iOut], "replace(", 8);
iOut += 8;
}
for(i=0; zText[i]; i++){
if( zText[i]=='\n' ){
memcpy(&zOut[iOut], zNL, nNL);
iOut += nNL;
}else if( zText[i]=='\r' ){
memcpy(&zOut[iOut], zCR, nCR);
iOut += nCR;
}else{
zOut[iOut] = zText[i];
iOut++;
}
}
if( zNL ){
memcpy(&zOut[iOut], ",'", 2); iOut += 2;
memcpy(&zOut[iOut], zNL, nNL); iOut += nNL;
memcpy(&zOut[iOut], "', char(10))", 12); iOut += 12;
}
if( zCR ){
memcpy(&zOut[iOut], ",'", 2); iOut += 2;
memcpy(&zOut[iOut], zCR, nCR); iOut += nCR;
memcpy(&zOut[iOut], "', char(13))", 12); iOut += 12;
}
sqlite3_result_text(context, zOut, iOut, SQLITE_TRANSIENT);
sqlite3_free(zOut);
return;
}
}
sqlite3_result_value(context, argv[0]);
}
/*
** This function is a no-op if recover handle p already contains an error
** (if p->errCode!=SQLITE_OK). A copy of the error code is returned in
** this case.
**
** Otherwise, an attempt is made to open the output database, attach
** and create the schema of the temporary database used to store
** intermediate data, and to register all required user functions and
** virtual table modules with the output handle.
**
** If no error occurs, SQLITE_OK is returned. Otherwise, an error code
** and error message are left in the recover handle and a copy of the
** error code returned.
*/
static int recoverOpenOutput(sqlite3_recover *p){
struct Func {
const char *zName;
int nArg;
void (*xFunc)(sqlite3_context*,int,sqlite3_value **);
} aFunc[] = {
{ "getpage", 1, recoverGetPage },
{ "page_is_used", 1, recoverPageIsUsed },
{ "read_i32", 2, recoverReadI32 },
{ "escape_crnl", 1, recoverEscapeCrnl },
};
const int flags = SQLITE_OPEN_URI|SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE;
sqlite3 *db = 0; /* New database handle */
int ii; /* For iterating through aFunc[] */
assert( p->dbOut==0 );
if( p->errCode==SQLITE_OK ){
if( sqlite3_open_v2(p->zUri, &db, flags, 0) ){
recoverDbError(p, db);
}else{
char *zSql = recoverMPrintf(p, "ATTACH %Q AS recovery;", p->zStateDb);
recoverExec(p, db, zSql);
recoverExec(p, db,
"PRAGMA writable_schema = 1;"
"CREATE TABLE recovery.map(pgno INTEGER PRIMARY KEY, parent INT);"
"CREATE TABLE recovery.schema(type, name, tbl_name, rootpage, sql);"
);
sqlite3_free(zSql);
}
}
/* Register the sqlite_dbdata and sqlite_dbptr virtual table modules.
** These two are registered with the output database handle - this
** module depends on the input handle supporting the sqlite_dbpage
** virtual table only. */
if( p->errCode==SQLITE_OK ){
p->errCode = sqlite3_dbdata_init(db, 0, 0);
}
/* Register the custom user-functions with the output handle. */
for(ii=0; p->errCode==SQLITE_OK && ii<sizeof(aFunc)/sizeof(aFunc[0]); ii++){
p->errCode = sqlite3_create_function(db, aFunc[ii].zName,
aFunc[ii].nArg, SQLITE_UTF8, (void*)p, aFunc[ii].xFunc, 0, 0
);
}
/* Truncate the output database to 0 pages in size. This is done by
** opening a new, empty, temp db, then using the backup API to clobber
** any existing output db with a copy of it. */
if( p->errCode==SQLITE_OK ){
sqlite3 *db2 = 0;
int rc = sqlite3_open("", &db2);
if( rc==SQLITE_OK ){
sqlite3_backup *pBackup = sqlite3_backup_init(db, "main", db2, "main");
if( pBackup ){
sqlite3_backup_step(pBackup, -1);
p->errCode = sqlite3_backup_finish(pBackup);
}else{
recoverDbError(p, db);
}
}else{
recoverDbError(p, db2);
}
sqlite3_close(db2);
}
p->dbOut = db;
return p->errCode;
}
/*
** This function is a no-op if recover handle p already contains an error
** (if p->errCode!=SQLITE_OK). A copy of the error code is returned in
** this case.
**
** Otherwise, attempt to populate temporary table "recovery.schema" with the
** parts of the database schema that can be extracted from the input database.
**
** If no error occurs, SQLITE_OK is returned. Otherwise, an error code
** and error message are left in the recover handle and a copy of the
** error code returned. It is not considered an error if part of all of
** the database schema cannot be recovered due to corruption.
*/
static int recoverCacheSchema(sqlite3_recover *p){
return recoverExec(p, p->dbOut,
"WITH RECURSIVE pages(p) AS ("
" SELECT 1"
" UNION"
" SELECT child FROM sqlite_dbptr('getpage()'), pages WHERE pgno=p"
")"
"INSERT INTO recovery.schema SELECT"
" max(CASE WHEN field=0 THEN value ELSE NULL END),"
" max(CASE WHEN field=1 THEN value ELSE NULL END),"
" max(CASE WHEN field=2 THEN value ELSE NULL END),"
" max(CASE WHEN field=3 THEN value ELSE NULL END),"
" max(CASE WHEN field=4 THEN value ELSE NULL END)"
"FROM sqlite_dbdata('getpage()') WHERE pgno IN ("
" SELECT p FROM pages"
") GROUP BY pgno, cell"
);
}
/*
** This function is a no-op if recover handle p already contains an error
** (if p->errCode!=SQLITE_OK).
**
** Otherwise, argument zName must be the name of a table that has just been
** created in the output database. This function queries the output db
** for the schema of said table, and creates a RecoverTable object to
** store the schema in memory. The new RecoverTable object is linked into
** the list at sqlite3_recover.pTblList.
**
** Parameter iRoot must be the root page of table zName in the INPUT
** database.
*/
static void recoverAddTable(
sqlite3_recover *p,
const char *zName, /* Name of table created in output db */
i64 iRoot /* Root page of same table in INPUT db */
){
sqlite3_stmt *pStmt = recoverPreparePrintf(p, p->dbOut,
"PRAGMA table_xinfo(%Q)", zName
);
if( pStmt ){
int iPk = -1;
int iBind = 1;
RecoverTable *pNew = 0;
int nCol = 0;
int nName = recoverStrlen(zName);
int nByte = 0;
while( sqlite3_step(pStmt)==SQLITE_ROW ){
nCol++;
nByte += (sqlite3_column_bytes(pStmt, 1)+1);
}
nByte += sizeof(RecoverTable) + nCol*sizeof(RecoverColumn) + nName+1;
recoverReset(p, pStmt);
pNew = recoverMalloc(p, nByte);
if( pNew ){
int i = 0;
int iField = 0;
char *csr = 0;
pNew->aCol = (RecoverColumn*)&pNew[1];
pNew->zTab = csr = (char*)&pNew->aCol[nCol];
pNew->nCol = nCol;
pNew->iRoot = iRoot;
memcpy(csr, zName, nName);
csr += nName+1;
for(i=0; sqlite3_step(pStmt)==SQLITE_ROW; i++){
int iPKF = sqlite3_column_int(pStmt, 5);
int n = sqlite3_column_bytes(pStmt, 1);
const char *z = (const char*)sqlite3_column_text(pStmt, 1);
const char *zType = (const char*)sqlite3_column_text(pStmt, 2);
int eHidden = sqlite3_column_int(pStmt, 6);
if( iPk==-1 && iPKF==1 && !sqlite3_stricmp("integer", zType) ) iPk = i;
if( iPKF>1 ) iPk = -2;
pNew->aCol[i].zCol = csr;
pNew->aCol[i].eHidden = eHidden;
if( eHidden==RECOVER_EHIDDEN_VIRTUAL ){
pNew->aCol[i].iField = -1;
}else{
pNew->aCol[i].iField = iField++;
}
if( eHidden!=RECOVER_EHIDDEN_VIRTUAL
&& eHidden!=RECOVER_EHIDDEN_STORED
){
pNew->aCol[i].iBind = iBind++;
}
memcpy(csr, z, n);
csr += (n+1);
}
pNew->pNext = p->pTblList;
p->pTblList = pNew;
pNew->bIntkey = 1;
}
recoverFinalize(p, pStmt);
pStmt = recoverPreparePrintf(p, p->dbOut, "PRAGMA index_xinfo(%Q)", zName);
while( pStmt && sqlite3_step(pStmt)==SQLITE_ROW ){
int iField = sqlite3_column_int(pStmt, 0);
int iCol = sqlite3_column_int(pStmt, 1);
assert( iField<pNew->nCol && iCol<pNew->nCol );
pNew->aCol[iCol].iField = iField;
pNew->bIntkey = 0;
iPk = -2;
}
recoverFinalize(p, pStmt);
if( p->errCode==SQLITE_OK ){
if( iPk>=0 ){
pNew->aCol[iPk].bIPK = 1;
}else if( pNew->bIntkey ){
pNew->iRowidBind = iBind++;
}
}
}
}
/*
** If this recover handle is not in SQL callback mode (i.e. was not created
** using sqlite3_recover_init_sql()) of if an error has already occurred,
** this function is a no-op. Otherwise, issue a callback with SQL statement
** zSql as the parameter.
**
** If the callback returns non-zero, set the recover handle error code to
** the value returned (so that the caller will abandon processing).
*/
static void recoverSqlCallback(sqlite3_recover *p, const char *zSql){
if( p->errCode==SQLITE_OK && p->xSql ){
int res = p->xSql(p->pSqlCtx, zSql);
if( res ){
recoverError(p, SQLITE_ERROR, "callback returned an error - %d", res);
}
}
}
/*
** This function is called after recoverCacheSchema() has cached those parts
** of the input database schema that could be recovered in temporary table
** "recovery.schema". This function creates in the output database copies
** of all parts of that schema that must be created before the tables can
** be populated. Specifically, this means:
**
** * all tables that are not VIRTUAL, and
** * UNIQUE indexes.
**
** If the recovery handle uses SQL callbacks, then callbacks containing
** the associated "CREATE TABLE" and "CREATE INDEX" statements are made.
**
** Additionally, records are added to the sqlite_schema table of the
** output database for any VIRTUAL tables. The CREATE VIRTUAL TABLE
** records are written directly to sqlite_schema, not actually executed.
** If the handle is in SQL callback mode, then callbacks are invoked
** with equivalent SQL statements.
*/
static int recoverWriteSchema1(sqlite3_recover *p){
sqlite3_stmt *pSelect = 0;
sqlite3_stmt *pTblname = 0;
pSelect = recoverPrepare(p, p->dbOut,
"WITH dbschema(rootpage, name, sql, tbl, isVirtual, isUnique) AS ("
" SELECT rootpage, name, sql, "
" type='table', "
" sql LIKE 'create virtual%',"
" (type='index' AND sql LIKE '%unique%')"
" FROM recovery.schema"
")"
"SELECT rootpage, tbl, isVirtual, name, sql"
" FROM dbschema "
" WHERE tbl OR isUnique"
" ORDER BY tbl DESC, name=='sqlite_sequence' DESC"
);
pTblname = recoverPrepare(p, p->dbOut,
"SELECT name FROM sqlite_schema "
"WHERE type='table' ORDER BY rowid DESC LIMIT 1"
);
if( pSelect ){
while( sqlite3_step(pSelect)==SQLITE_ROW ){
i64 iRoot = sqlite3_column_int64(pSelect, 0);
int bTable = sqlite3_column_int(pSelect, 1);
int bVirtual = sqlite3_column_int(pSelect, 2);
const char *zName = (const char*)sqlite3_column_text(pSelect, 3);
const char *zSql = (const char*)sqlite3_column_text(pSelect, 4);
char *zFree = 0;
int rc = SQLITE_OK;
if( bVirtual ){
zSql = (const char*)(zFree = recoverMPrintf(p,
"INSERT INTO sqlite_schema VALUES('table', %Q, %Q, 0, %Q)",
zName, zName, zSql
));
}
rc = sqlite3_exec(p->dbOut, zSql, 0, 0, 0);
if( rc==SQLITE_OK ){
recoverSqlCallback(p, zSql);
if( bTable && !bVirtual ){
if( SQLITE_ROW==sqlite3_step(pTblname) ){
const char *zTbl = (const char*)sqlite3_column_text(pTblname, 0);
recoverAddTable(p, zTbl, iRoot);
}
recoverReset(p, pTblname);
}
}else if( rc!=SQLITE_ERROR ){
recoverDbError(p, p->dbOut);
}
sqlite3_free(zFree);
}
}
recoverFinalize(p, pSelect);
recoverFinalize(p, pTblname);
return p->errCode;
}
/*
** This function is called after the output database has been populated. It
** adds all recovered schema elements that were not created in the output
** database by recoverWriteSchema1() - everything except for tables and
** UNIQUE indexes. Specifically:
**
** * views,
** * triggers,
** * non-UNIQUE indexes.
**
** If the recover handle is in SQL callback mode, then equivalent callbacks
** are issued to create the schema elements.
*/
static int recoverWriteSchema2(sqlite3_recover *p){
sqlite3_stmt *pSelect = 0;
pSelect = recoverPrepare(p, p->dbOut,
"SELECT rootpage, sql FROM recovery.schema "
" WHERE type!='table' AND (type!='index' OR sql NOT LIKE '%unique%')"
);
if( pSelect ){
while( sqlite3_step(pSelect)==SQLITE_ROW ){
const char *zSql = (const char*)sqlite3_column_text(pSelect, 1);
int rc = sqlite3_exec(p->dbOut, zSql, 0, 0, 0);
if( rc==SQLITE_OK ){
recoverSqlCallback(p, zSql);
}else if( rc!=SQLITE_ERROR ){
recoverDbError(p, p->dbOut);
}
}
}
recoverFinalize(p, pSelect);
return p->errCode;
}
/*
** This function is a no-op if recover handle p already contains an error
** (if p->errCode!=SQLITE_OK). In this case it returns NULL.
**
** Otherwise, if the recover handle is configured to create an output
** database (was created by sqlite3_recover_init()), then this function
** prepares and returns an SQL statement to INSERT a new record into table
** pTab, assuming the first nField fields of a record extracted from disk
** are valid.
**
** For example, if table pTab is:
**
** CREATE TABLE name(a, b GENERATED ALWAYS AS (a+1) STORED, c, d, e);
**
** And nField is 4, then the SQL statement prepared and returned is:
**
** INSERT INTO (a, c, d) VALUES (?1, ?2, ?3);
**
** In this case even though 4 values were extracted from the input db,
** only 3 are written to the output, as the generated STORED column
** cannot be written.
**
** If the recover handle is in SQL callback mode, then the SQL statement
** prepared is such that evaluating it returns a single row containing
** a single text value - itself an SQL statement similar to the above,
** except with SQL literals in place of the variables. For example:
**
** SELECT 'INSERT INTO (a, c, d) VALUES ('
** || quote(?1) || ', '
** || quote(?2) || ', '
** || quote(?3) || ')';
**
** In either case, it is the responsibility of the caller to eventually
** free the statement handle using sqlite3_finalize().
*/
static sqlite3_stmt *recoverInsertStmt(
sqlite3_recover *p,
RecoverTable *pTab,
int nField
){
sqlite3_stmt *pRet = 0;
const char *zSep = "";
const char *zSqlSep = "";
char *zSql = 0;
char *zFinal = 0;
char *zBind = 0;
int ii;
int bSql = p->xSql ? 1 : 0;
if( nField<=0 ) return 0;
assert( nField<=pTab->nCol );
zSql = recoverMPrintf(p, "INSERT OR IGNORE INTO %Q(", pTab->zTab);
if( pTab->iRowidBind ){
assert( pTab->bIntkey );
zSql = recoverMPrintf(p, "%z_rowid_", zSql);
if( bSql ){
zBind = recoverMPrintf(p, "%zquote(?%d)", zBind, pTab->iRowidBind);
}else{
zBind = recoverMPrintf(p, "%z?%d", zBind, pTab->iRowidBind);
}
zSqlSep = "||', '||";
zSep = ", ";
}
for(ii=0; ii<nField; ii++){
int eHidden = pTab->aCol[ii].eHidden;
if( eHidden!=RECOVER_EHIDDEN_VIRTUAL
&& eHidden!=RECOVER_EHIDDEN_STORED
){
assert( pTab->aCol[ii].iField>=0 && pTab->aCol[ii].iBind>=1 );
zSql = recoverMPrintf(p, "%z%s%Q", zSql, zSep, pTab->aCol[ii].zCol);
if( bSql ){
zBind = recoverMPrintf(p,
"%z%sescape_crnl(quote(?%d))", zBind, zSqlSep, pTab->aCol[ii].iBind
);
zSqlSep = "||', '||";
}else{
zBind = recoverMPrintf(p, "%z%s?%d", zBind, zSep, pTab->aCol[ii].iBind);
}
zSep = ", ";
}
}
if( bSql ){
zFinal = recoverMPrintf(p, "SELECT %Q || ') VALUES (' || %s || ')'",
zSql, zBind
);
}else{
zFinal = recoverMPrintf(p, "%s) VALUES (%s)", zSql, zBind);
}
pRet = recoverPrepare(p, p->dbOut, zFinal);
sqlite3_free(zSql);
sqlite3_free(zBind);
sqlite3_free(zFinal);
return pRet;
}
/*
** Search the list of RecoverTable objects at p->pTblList for one that
** has root page iRoot in the input database. If such an object is found,
** return a pointer to it. Otherwise, return NULL.
*/
static RecoverTable *recoverFindTable(sqlite3_recover *p, u32 iRoot){
RecoverTable *pRet = 0;
for(pRet=p->pTblList; pRet && pRet->iRoot!=iRoot; pRet=pRet->pNext);
return pRet;
}
/*
** This function attempts to create a lost and found table within the
** output db. If successful, it returns a pointer to a buffer containing
** the name of the new table. It is the responsibility of the caller to
** eventually free this buffer using sqlite3_free().
**
** If an error occurs, NULL is returned and an error code and error
** message left in the recover handle.
*/
static char *recoverLostAndFoundCreate(
sqlite3_recover *p, /* Recover object */
int nField /* Number of column fields in new table */
){
char *zTbl = 0;
sqlite3_stmt *pProbe = 0;
int ii = 0;
pProbe = recoverPrepare(p, p->dbOut,
"SELECT 1 FROM sqlite_schema WHERE name=?"
);
for(ii=-1; zTbl==0 && p->errCode==SQLITE_OK && ii<1000; ii++){
int bFail = 0;
if( ii<0 ){
zTbl = recoverMPrintf(p, "%s", p->zLostAndFound);
}else{
zTbl = recoverMPrintf(p, "%s_%d", p->zLostAndFound, ii);
}
if( p->errCode==SQLITE_OK ){
sqlite3_bind_text(pProbe, 1, zTbl, -1, SQLITE_STATIC);
if( SQLITE_ROW==sqlite3_step(pProbe) ){
bFail = 1;
}
recoverReset(p, pProbe);
}
if( bFail ){
sqlite3_clear_bindings(pProbe);
sqlite3_free(zTbl);
zTbl = 0;
}
}
recoverFinalize(p, pProbe);
if( zTbl ){
const char *zSep = 0;
char *zField = 0;
char *zSql = 0;
zSep = "rootpgno INTEGER, pgno INTEGER, nfield INTEGER, id INTEGER, ";
for(ii=0; p->errCode==SQLITE_OK && ii<nField; ii++){
zField = recoverMPrintf(p, "%z%sc%d", zField, zSep, ii);
zSep = ", ";
}
zSql = recoverMPrintf(p, "CREATE TABLE %s(%s)", zTbl, zField);
sqlite3_free(zField);
recoverExec(p, p->dbOut, zSql);
recoverSqlCallback(p, zSql);
sqlite3_free(zSql);
}else if( p->errCode==SQLITE_OK ){
recoverError(
p, SQLITE_ERROR, "failed to create %s output table", p->zLostAndFound
);
}
return zTbl;
}
/*
** Synthesize and prepare an INSERT statement to write to the lost_and_found
** table in the output database. The name of the table is zTab, and it has
** nField c* fields.
*/
static sqlite3_stmt *recoverLostAndFoundInsert(
sqlite3_recover *p,
const char *zTab,
int nField
){
int nTotal = nField + 4;
int ii;
char *zBind = 0;
sqlite3_stmt *pRet = 0;
if( p->xSql==0 ){
for(ii=0; ii<nTotal; ii++){
zBind = recoverMPrintf(p, "%z%s?", zBind, zBind?", ":"", ii);
}
pRet = recoverPreparePrintf(
p, p->dbOut, "INSERT INTO %s VALUES(%s)", zTab, zBind
);
}else{
const char *zSep = "";
for(ii=0; ii<nTotal; ii++){
zBind = recoverMPrintf(p, "%z%squote(?)", zBind, zSep);
zSep = "|| ', ' ||";
}
pRet = recoverPreparePrintf(
p, p->dbOut, "SELECT 'INSERT INTO %s VALUES(' || %s || ')'", zTab, zBind
);
}
sqlite3_free(zBind);
return pRet;
}
/*
** Helper function for recoverLostAndFound().
*/
static void recoverLostAndFoundPopulate(
sqlite3_recover *p,
sqlite3_stmt *pInsert,
int nField
){
sqlite3_stmt *pStmt = recoverPrepare(p, p->dbOut,
"WITH RECURSIVE pages(root, page) AS ("
" SELECT pgno, pgno FROM recovery.map WHERE parent IS NULL"
" UNION"
" SELECT root, child FROM sqlite_dbptr('getpage()'), pages "
" WHERE pgno=page"
") "
"SELECT root, page, cell, field, value "
"FROM sqlite_dbdata('getpage()') d, pages p WHERE p.page=d.pgno "
" AND NOT page_is_used(page) "
"UNION ALL "
"SELECT 0, 0, 0, 0, 0"
);
sqlite3_value **apVal = 0;
int nVal = -1;
i64 iRowid = 0;
int bHaveRowid = 0;
int ii;
i64 iPrevRoot = -1;
i64 iPrevPage = -1;
int iPrevCell = -1;
apVal = (sqlite3_value**)recoverMalloc(p, nField*sizeof(sqlite3_value*));
while( p->errCode==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
i64 iRoot = sqlite3_column_int64(pStmt, 0);
i64 iPage = sqlite3_column_int64(pStmt, 1);
int iCell = sqlite3_column_int64(pStmt, 2);
int iField = sqlite3_column_int64(pStmt, 3);
if( iPrevRoot>0 && (iPrevPage!=iPage || iPrevCell!=iCell) ){
/* Insert the new row */
sqlite3_bind_int64(pInsert, 1, iPrevRoot); /* rootpgno */
sqlite3_bind_int64(pInsert, 2, iPrevPage); /* pgno */
sqlite3_bind_int(pInsert, 3, nVal); /* nfield */
if( bHaveRowid ){
sqlite3_bind_int64(pInsert, 4, iRowid); /* id */
}
for(ii=0; ii<nVal; ii++){
recoverBindValue(p, pInsert, 5+ii, apVal[ii]);
}
if( sqlite3_step(pInsert)==SQLITE_ROW ){
recoverSqlCallback(p, (const char*)sqlite3_column_text(pInsert, 0));
}
recoverReset(p, pInsert);
/* Discard the accumulated row data */
for(ii=0; ii<nVal; ii++){
sqlite3_value_free(apVal[ii]);
apVal[ii] = 0;
}
sqlite3_clear_bindings(pInsert);
bHaveRowid = 0;
nVal = -1;
}
if( iField<0 ){
assert( nVal==-1 );
iRowid = sqlite3_column_int64(pStmt, 4);
bHaveRowid = 1;
nVal = 0;
}else if( iField<nField && iRoot!=0 ){
sqlite3_value *pVal = sqlite3_column_value(pStmt, 4);
apVal[iField] = sqlite3_value_dup(pVal);
assert( iField==nVal || (nVal==-1 && iField==0) );
nVal = iField+1;
if( apVal[iField]==0 ){
recoverError(p, SQLITE_NOMEM, 0);
}
}
iPrevRoot = iRoot;
iPrevPage = iPage;
iPrevCell = iCell;
}
recoverFinalize(p, pStmt);
for(ii=0; ii<nVal; ii++){
sqlite3_value_free(apVal[ii]);
apVal[ii] = 0;
}
sqlite3_free(apVal);
}
/*
** This function searches for orphaned rows in the input database. If
** any are found, it creates the lost-and-found table in the output
** db and writes all orphaned rows to it. Or, if the recover handle is
** in SQL callback mode, issues equivalent callbacks.
*/
static void recoverLostAndFound(sqlite3_recover *p){
i64 nPg = 0;
RecoverBitmap *pMap = 0;
nPg = recoverPageCount(p);
pMap = p->pUsed = recoverBitmapAlloc(p, nPg);
if( pMap ){
char *zTab = 0; /* Name of lost_and_found table */
sqlite3_stmt *pInsert = 0; /* INSERT INTO lost_and_found ... */
int nField = 0;
/* Add all pages that are part of any tree in the recoverable part of
** the input database schema to the bitmap. */
sqlite3_stmt *pStmt = recoverPrepare(
p, p->dbOut,
"WITH roots(r) AS ("
" SELECT 1 UNION ALL"
" SELECT rootpage FROM recovery.schema WHERE rootpage>0"
"),"
"used(page) AS ("
" SELECT r FROM roots"
" UNION"
" SELECT child FROM sqlite_dbptr('getpage()'), used "
" WHERE pgno=page"
") "
"SELECT page FROM used"
);
while( pStmt && SQLITE_ROW==sqlite3_step(pStmt) ){
i64 iPg = sqlite3_column_int64(pStmt, 0);
recoverBitmapSet(pMap, iPg);
}
recoverFinalize(p, pStmt);
/* Add all pages that appear to be part of the freelist to the bitmap. */
if( p->bFreelistCorrupt==0 ){
pStmt = recoverPrepare(p, p->dbOut,
"WITH trunk(pgno) AS ("
" SELECT read_i32(getpage(1), 8) AS x WHERE x>0"
" UNION"
" SELECT read_i32(getpage(trunk.pgno), 0) AS x FROM trunk WHERE x>0"
"),"
"trunkdata(pgno, data) AS ("
" SELECT pgno, getpage(pgno) FROM trunk"
"),"
"freelist(data, n, freepgno) AS ("
" SELECT data, min(16384, read_i32(data, 1)-1), pgno FROM trunkdata"
" UNION ALL"
" SELECT data, n-1, read_i32(data, 2+n) FROM freelist WHERE n>=0"
")"
"SELECT freepgno FROM freelist"
);
while( pStmt && SQLITE_ROW==sqlite3_step(pStmt) ){
i64 iPg = sqlite3_column_int64(pStmt, 0);
recoverBitmapSet(pMap, iPg);
}
recoverFinalize(p, pStmt);
}
/* Add an entry for each page not already added to the bitmap to
** the recovery.map table. This loop leaves the "parent" column
** of each recovery.map row set to NULL - to be filled in below. */
pStmt = recoverPreparePrintf(
p, p->dbOut,
"WITH RECURSIVE seq(ii) AS ("
" SELECT 1 UNION ALL SELECT ii+1 FROM seq WHERE ii<%lld"
")"
"INSERT INTO recovery.map(pgno) "
" SELECT ii FROM seq WHERE NOT page_is_used(ii)", nPg
);
sqlite3_step(pStmt);
recoverFinalize(p, pStmt);
/* Set the "parent" column for each row of the recovery.map table */
pStmt = recoverPrepare(
p, p->dbOut,
"UPDATE recovery.map SET parent = ptr.pgno "
" FROM sqlite_dbptr('getpage()') AS ptr "
" WHERE recovery.map.pgno=ptr.child"
);
sqlite3_step(pStmt);
recoverFinalize(p, pStmt);
/* Figure out the number of fields in the longest record that will be
** recovered into the lost_and_found table. Set nField to this value. */
pStmt = recoverPrepare(
p, p->dbOut,
"SELECT max(field)+1 FROM sqlite_dbdata('getpage') WHERE pgno IN ("
" SELECT pgno FROM recovery.map"
")"
);
if( pStmt && SQLITE_ROW==sqlite3_step(pStmt) ){
nField = sqlite3_column_int64(pStmt, 0);
}
recoverFinalize(p, pStmt);
if( nField>0 ){
zTab = recoverLostAndFoundCreate(p, nField);
pInsert = recoverLostAndFoundInsert(p, zTab, nField);
recoverLostAndFoundPopulate(p, pInsert, nField);
recoverFinalize(p, pInsert);
sqlite3_free(zTab);
}
}
}
/*
** For each table in the recovered schema, this function extracts as much
** data as possible from the output database and writes it to the input
** database. Or, if the recover handle is in SQL callback mode, issues
** equivalent callbacks.
**
** It does not recover "orphaned" data into the lost-and-found table.
** See recoverLostAndFound() for that.
*/
static int recoverWriteData(sqlite3_recover *p){
RecoverTable *pTbl;
int nMax = 0;
sqlite3_value **apVal = 0;
sqlite3_stmt *pTbls = 0;
sqlite3_stmt *pSel = 0;
/* Figure out the maximum number of columns for any table in the schema */
for(pTbl=p->pTblList; pTbl; pTbl=pTbl->pNext){
if( pTbl->nCol>nMax ) nMax = pTbl->nCol;
}
apVal = (sqlite3_value**)recoverMalloc(p, sizeof(sqlite3_value*) * (nMax+1));
if( apVal==0 ) return p->errCode;
pTbls = recoverPrepare(p, p->dbOut,
"SELECT rootpage FROM recovery.schema "
" WHERE type='table' AND (sql NOT LIKE 'create virtual%')"
" ORDER BY (tbl_name='sqlite_sequence') ASC"
);
pSel = recoverPrepare(p, p->dbOut,
"WITH RECURSIVE pages(page) AS ("
" SELECT ?1"
" UNION"
" SELECT child FROM sqlite_dbptr('getpage()'), pages "
" WHERE pgno=page"
") "
"SELECT page, cell, field, value "
"FROM sqlite_dbdata('getpage()') d, pages p WHERE p.page=d.pgno "
"UNION ALL "
"SELECT 0, 0, 0, 0"
);
if( pSel ){
/* The outer loop runs once for each table to recover. */
while( sqlite3_step(pTbls)==SQLITE_ROW ){
i64 iRoot = sqlite3_column_int64(pTbls, 0);
RecoverTable *pTab = recoverFindTable(p, iRoot);
if( pTab ){
int ii;
sqlite3_stmt *pInsert = 0;
int nInsert = -1;
i64 iPrevPage = -1;
int iPrevCell = -1;
int bHaveRowid = 0; /* True if iRowid is valid */
i64 iRowid = 0;
int nVal = -1;
if( sqlite3_stricmp("sqlite_sequence", pTab->zTab)==0 ){
recoverExec(p, p->dbOut, "DELETE FROM sqlite_sequence");
recoverSqlCallback(p, "DELETE FROM sqlite_sequence");
}
sqlite3_bind_int64(pSel, 1, iRoot);
while( p->errCode==SQLITE_OK && sqlite3_step(pSel)==SQLITE_ROW ){
i64 iPage = sqlite3_column_int64(pSel, 0);
int iCell = sqlite3_column_int(pSel, 1);
int iField = sqlite3_column_int(pSel, 2);
sqlite3_value *pVal = sqlite3_column_value(pSel, 3);
int bNewCell = (iPrevPage!=iPage || iPrevCell!=iCell);
assert( bNewCell==0 || (iField==-1 || iField==0) );
assert( bNewCell || iField==nVal || nVal==pTab->nCol );
if( bNewCell ){
if( nVal>=0 ){
if( pInsert==0 || nVal!=nInsert ){
recoverFinalize(p, pInsert);
pInsert = recoverInsertStmt(p, pTab, nVal);
nInsert = nVal;
}
if( nVal>0 ){
for(ii=0; ii<pTab->nCol; ii++){
RecoverColumn *pCol = &pTab->aCol[ii];
int iBind = pCol->iBind;
if( iBind>0 ){
if( pCol->bIPK ){
sqlite3_bind_int64(pInsert, iBind, iRowid);
}else if( pCol->iField<nVal ){
recoverBindValue(p, pInsert, iBind, apVal[pCol->iField]);
}
}
}
if( p->bRecoverRowid && pTab->iRowidBind>0 && bHaveRowid ){
sqlite3_bind_int64(pInsert, pTab->iRowidBind, iRowid);
}
if( SQLITE_ROW==sqlite3_step(pInsert) ){
const char *z = (const char*)sqlite3_column_text(pInsert, 0);
recoverSqlCallback(p, z);
}
recoverReset(p, pInsert);
assert( p->errCode || pInsert );
if( pInsert ) sqlite3_clear_bindings(pInsert);
}
}
for(ii=0; ii<nVal; ii++){
sqlite3_value_free(apVal[ii]);
apVal[ii] = 0;
}
nVal = -1;
bHaveRowid = 0;
}
if( iPage!=0 ){
if( iField<0 ){
iRowid = sqlite3_column_int64(pSel, 3);
assert( nVal==-1 );
nVal = 0;
bHaveRowid = 1;
}else if( iField<pTab->nCol ){
assert( apVal[iField]==0 );
apVal[iField] = sqlite3_value_dup( pVal );
if( apVal[iField]==0 ){
recoverError(p, SQLITE_NOMEM, 0);
}
nVal = iField+1;
}
iPrevCell = iCell;
iPrevPage = iPage;
}
}
recoverReset(p, pSel);
recoverFinalize(p, pInsert);
pInsert = 0;
for(ii=0; ii<nVal; ii++){
sqlite3_value_free(apVal[ii]);
apVal[ii] = 0;
}
}
}
}
recoverFinalize(p, pTbls);
recoverFinalize(p, pSel);
sqlite3_free(apVal);
return p->errCode;
}
/*
** This function does the work of sqlite3_recover_run(). It is assumed that
** no error has occurred when this is called. If an error occurs during
** the recovery operation, an error code and error message are left in
** the recovery handle.
*/
static void recoverRun(sqlite3_recover *p){
RecoverTable *pTab = 0;
RecoverTable *pNext = 0;
int rc = SQLITE_OK;
assert( p->errCode==SQLITE_OK );
assert( p->bRun==0 );
p->bRun = 1;
recoverSqlCallback(p, "BEGIN");
recoverSqlCallback(p, "PRAGMA writable_schema = on");
/* Open the output database. And register required virtual tables and
** user functions with the new handle. */
recoverOpenOutput(p);
/* Open transactions on both the input and output databases. */
recoverExec(p, p->dbIn, "BEGIN");
recoverExec(p, p->dbOut, "BEGIN");
recoverCacheSchema(p);
recoverWriteSchema1(p);
recoverWriteData(p);
if( p->zLostAndFound ) recoverLostAndFound(p);
recoverWriteSchema2(p);
/* If no error has occurred, commit the write transaction on the output
** database. Then end the read transaction on the input database, regardless
** of whether or not prior errors have occurred. */
recoverExec(p, p->dbOut, "COMMIT");
rc = sqlite3_exec(p->dbIn, "END", 0, 0, 0);
if( p->errCode==SQLITE_OK ) p->errCode = rc;
recoverSqlCallback(p, "PRAGMA writable_schema = off");
recoverSqlCallback(p, "COMMIT");
/* Clean up various resources allocated by this function. */
for(pTab=p->pTblList; pTab; pTab=pNext){
pNext = pTab->pNext;
sqlite3_free(pTab);
}
p->pTblList = 0;
sqlite3_finalize(p->pGetPage);
p->pGetPage = 0;
recoverBitmapFree(p->pUsed);
p->pUsed = 0;
sqlite3_close(p->dbOut);
}
/*
** This is a worker function that does the heavy lifting for both init
** functions:
**
** sqlite3_recover_init()
** sqlite3_recover_init_sql()
**
** All this function does is allocate space for the recover handle and
** take copies of the input parameters. All the real work is done within
** sqlite3_recover_run().
*/
sqlite3_recover *recoverInit(
sqlite3* db,
const char *zDb,
const char *zUri, /* Output URI for _recover_init() */
int (*xSql)(void*, const char*),/* SQL callback for _recover_init_sql() */
void *pSqlCtx /* Context arg for _recover_init_sql() */
){
sqlite3_recover *pRet = 0;
int nDb = 0;
int nUri = 0;
int nByte = 0;
if( zDb==0 ){ zDb = "main"; }
nDb = recoverStrlen(zDb);
nUri = recoverStrlen(zUri);
nByte = sizeof(sqlite3_recover) + nDb+1 + nUri+1;
pRet = (sqlite3_recover*)sqlite3_malloc(nByte);
if( pRet ){
memset(pRet, 0, nByte);
pRet->dbIn = db;
pRet->zDb = (char*)&pRet[1];
pRet->zUri = &pRet->zDb[nDb+1];
memcpy(pRet->zDb, zDb, nDb);
if( nUri>0 ) memcpy(pRet->zUri, zUri, nUri);
pRet->xSql = xSql;
pRet->pSqlCtx = pSqlCtx;
pRet->bRecoverRowid = RECOVER_ROWID_DEFAULT;
}
return pRet;
}
/*
** Initialize a recovery handle that creates a new database containing
** the recovered data.
*/
sqlite3_recover *sqlite3_recover_init(
sqlite3* db,
const char *zDb,
const char *zUri
){
return recoverInit(db, zDb, zUri, 0, 0);
}
/*
** Initialize a recovery handle that returns recovered data in the
** form of SQL statements via a callback.
*/
sqlite3_recover *sqlite3_recover_init_sql(
sqlite3* db,
const char *zDb,
int (*xSql)(void*, const char*),
void *pSqlCtx
){
return recoverInit(db, zDb, 0, xSql, pSqlCtx);
}
/*
** Return the handle error message, if any.
*/
const char *sqlite3_recover_errmsg(sqlite3_recover *p){
return (p && p->errCode!=SQLITE_NOMEM) ? p->zErrMsg : "out of memory";
}
/*
** Return the handle error code.
*/
int sqlite3_recover_errcode(sqlite3_recover *p){
return p ? p->errCode : SQLITE_NOMEM;
}
/*
** Configure the handle.
*/
int sqlite3_recover_config(sqlite3_recover *p, int op, void *pArg){
int rc = SQLITE_OK;
if( p==0 ) return SQLITE_NOMEM;
switch( op ){
case 789:
sqlite3_free(p->zStateDb);
p->zStateDb = recoverMPrintf(p, "%s", (char*)pArg);
break;
case SQLITE_RECOVER_LOST_AND_FOUND: {
const char *zArg = (const char*)pArg;
sqlite3_free(p->zLostAndFound);
if( zArg ){
p->zLostAndFound = recoverMPrintf(p, "%s", zArg);
}else{
p->zLostAndFound = 0;
}
break;
}
case SQLITE_RECOVER_FREELIST_CORRUPT:
p->bFreelistCorrupt = *(int*)pArg;
break;
case SQLITE_RECOVER_ROWIDS:
p->bRecoverRowid = *(int*)pArg;
break;
default:
rc = SQLITE_NOTFOUND;
break;
}
return rc;
}
/*
** Do the configured recovery operation. Return SQLITE_OK if successful, or
** else an SQLite error code.
*/
int sqlite3_recover_run(sqlite3_recover *p){
if( p ){
recoverExec(p, p->dbIn, "PRAGMA writable_schema=1");
if( p->bRun ) return SQLITE_MISUSE; /* Has already run */
if( p->errCode==SQLITE_OK ) recoverRun(p);
if( sqlite3_exec(p->dbIn, "PRAGMA writable_schema=0", 0, 0, 0) ){
recoverDbError(p, p->dbIn);
}
}
return p ? p->errCode : SQLITE_NOMEM;
}
/*
** Free all resources associated with the recover handle passed as the only
** argument. The results of using a handle with any sqlite3_recover_**
** API function after it has been passed to this function are undefined.
**
** A copy of the value returned by the first call made to sqlite3_recover_run()
** on this handle is returned, or SQLITE_OK if sqlite3_recover_run() has
** not been called on this handle.
*/
int sqlite3_recover_finish(sqlite3_recover *p){
int rc;
if( p==0 ){
rc = SQLITE_NOMEM;
}else{
rc = p->errCode;
sqlite3_free(p->zErrMsg);
sqlite3_free(p->zStateDb);
sqlite3_free(p->zLostAndFound);
sqlite3_free(p);
}
return rc;
}
Reference in New Issue View Git Blame Copy Permalink