Hi,
I am trying to get sqlite working on a freertos/fatfs based STM32 embedded
system.
I started from the 3.24.0 amalgamation an did the steps in
https://www.sqlite.org/custombuild.html.
The VFS is based on the https://www.sqlite.org/src/doc/trunk/src/test_demovfs.c
code (though I did implement the truncate method).
Compilation flags are:
SQLITE_MUTEX_APPDEF=1
SQLITE_OS_OTHER=1
SQLITE_OMIT_WAL=1
SQLITE_TEMP_STORE=3
SQLITE_ENABLE_8_3_NAMES=2
I am running into the problem that when I try to create a table using
sql ="CREATE TABLE Cars(Id INT, Name TEXT, Price INT);" ;/* Create
SQL statement */
rc = sqlite3_exec(db, sql, NULL, NULL, &zErrMsg);/* Execute SQL
statement */
(full sample code below) I get a SQLITE_NOTADB.
Searching the mailing list archive there was a similar post a few years ago
(https://www.mail-archive.com/sqlite-users@mailinglists.sqlite.org/msg96723.html),
but in that case it was a problem with the journal file it seems
(https://stackoverflow.com/questions/35738578/sqlite-porting-on-freertos-with-stm32).
In my case demoOpen is called only once for the main database and that one is
in read/write mode so I am encountering a different problem it seems.
Looking with a debugger the stack trace when it goes wrong is:
sqlite3_exec
sqlite3_step
sqlite3Step
sqlite3VdbeExec
sqlite3BtreeBeginTrans
lockBtree
He reads a page from the file in sqlite3PagerSharedLock, but the file is still
0 so the page is all zeros.
pPage1->aData points to a buffer with all 0's
sqlite3PagerPagecount(pBt->pPager, &nPageFile); //sets nPageFile to 1
if( nPage==0 || memcmp(24+(u8*)pPage1->aData, 92+(u8*)pPage1->aData,4)!=0 ){
nPage = nPageFile;
} // changes nPage from 0 to 1
if( (pBt->db->flags & SQLITE_ResetDatabase)!=0 ){
nPage = 0;
} // Since pBt->db->flags = 0x00048060 and SQLITE_ResetDatabase =
0x02000000 , this keeps nPage as 1
So it triggers the SQLITE_NOTADB case
if( nPage>0 )
{
u32 pageSize;
u32 usableSize;
u8 *page1 = pPage1->aData;
rc = SQLITE_NOTADB;
/* EVIDENCE-OF: R-43737-39999 Every valid SQLite database file begins
** with the following 16 bytes (in hex): 53 51 4c 69 74 65 20 66 6f 72 6d
** 61 74 20 33 00.
*/
if( memcmp(page1, zMagicHeader, 16)!=0 )
{
goto page1_init_failed;
}
So I have been trying to figure out how the magic header should end up in the
database file.
I does not seem to happen when the database opened in the sqlite3_open_v2 call.
That just opens/creates the file in RW mode, but does not yet write any data to
it (behaviour on a windows PC seems to same so I guess this is OK)
Writing the magic header seems to be done in a function
static int newDatabase(BtShared *pBt)
And I am assuming this function should be called from sqlite3BtreeBeginTrans in
a part of the code that looks like:
pBt->btsFlags &= ~BTS_INITIALLY_EMPTY;
if( pBt->nPage==0 ) pBt->btsFlags |= BTS_INITIALLY_EMPTY;
do {
/* Call lockBtree() until either pBt->pPage1 is populated or
** lockBtree() returns something other than SQLITE_OK. lockBtree()
** may return SQLITE_OK but leave pBt->pPage1 set to 0 if after
** reading page 1 it discovers that the page-size of the database
** file is not pBt->pageSize. In this case lockBtree() will update
** pBt->pageSize to the page-size of the file on disk.
*/
while( pBt->pPage1==0 && SQLITE_OK==(rc = lockBtree(pBt)) );
if( rc==SQLITE_OK && wrflag ){
if( (pBt->btsFlags & BTS_READ_ONLY)!=0 ){
rc = SQLITE_READONLY;
}else{
rc = sqlite3PagerBegin(pBt->pPager,wrflag>1,sqlite3TempInMemory(p->db));
if( rc==SQLITE_OK ){
rc = newDatabase(pBt); //
<---------------------------------------------------------------------------------------------------HERE
}
}
}
if( rc!=SQLITE_OK ){
unlockBtreeIfUnused(pBt);
}
}while( (rc&0xFF)==SQLITE_BUSY && pBt->inTransaction==TRANS_NONE &&
btreeInvokeBusyHandler(pBt) );
but if I analyse code execution this statement is never executed in the cases I
end up in sqlite3BtreeBeginTrans
[1] First time I am there is with stack trace:
sqlite3_exec
sqlite3_prepare_v2
sqlite3LockAndPrepare
sqlite3Prepare
sqlite3RunParser
sqlite3Parser
yy_reduce
sqlite3StartTable
sqlite3ReadSchema
sqlite3Init
sqlite3InitOne
sqlite3BtreeBeginTrans
But in sqlite3InitOne, it is called with sqlite3BtreeBeginTrans(pDb->pBt, 0);
so wrflag is 0, so the newDatabase part is not executed.
[2] I get there a second time with stack trace:
sqlite3_exec
sqlite3_prepare_v2
sqlite3LockAndPrepare
sqlite3Prepare
sqlite3RunParser
sqlite3Parser
yy_reduce
sqlite3StartTable
sqlite3ReadSchema
sqlite3Init
sqlite3InitOne
sqlite3_exec
sqlite3_step
sqlite3Step
sqlite3VdbeExec
sqlite3BtreeBeginTrans(pBt, pOp->p2); //pOp->p2 = 0 again (pOp->opcode = 0x02)
So since pOp->p2 is 0, again wrflag is 0, so the newDatabase part is not
executed.
And since
if( p->inTrans==TRANS_WRITE || (p->inTrans==TRANS_READ && !wrflag) ){
goto trans_begun;
}
is true (p->inTrans = 0x1 (= TRANS_READ)) we make the jump over it already in
the beginning.
[3] Then the 3th time is the one where I get the error.
sqlite3_exec
sqlite3_step
sqlite3Step
sqlite3VdbeExec
sqlite3BtreeBeginTrans
The call is sqlite3BtreeBeginTrans(pBt, pOp->p2); with pOp->p2 = 1, pOp->opcode
= 0x02
But now we get the error already in the lockBtree part of
while( pBt->pPage1==0 && SQLITE_OK==(rc = lockBtree(pBt)) );
So again newDatabase will not be called because that happens only afterwards.
The code I am using to test is the same as in the original thread I already
refered to:
{
sqlite3 *db = NULL;
char *zErrMsg = 0;
int rc;
char *sql;
l_nIntermediateResult = e_RETURNVALUE_Success;
if ( e_RETURNVALUE_Success == l_nIntermediateResult)
{
//mmm this is also done by sqlite3_os_init but it does not harm to
do it twice i think
rc = sqlite3_vfs_register(sqlite3_demovfs(), 1); /* Register a VFS
*/
if(rc != SQLITE_OK)
{
LOGGER_LOG_FATAL(LOG_CLASS, "Could not register sqlite vfs:
%d", rc);
l_nIntermediateResult = e_RETURNVALUE_Failure;
}
}
if ( e_RETURNVALUE_Success == l_nIntermediateResult)
{
rc = sqlite3_open_v2("testsql.db", &db, SQLITE_OPEN_READWRITE |
SQLITE_OPEN_CREATE , "demo" );/* Create a SQL table */
if( rc )
{
LOGGER_LOG_FATAL(LOG_CLASS, "Could not create table: %d", rc);
l_nIntermediateResult = e_RETURNVALUE_Failure;
}
}
#if 0 // I disabled disabling the journal but it makes no difference
if ( e_RETURNVALUE_Success == l_nIntermediateResult)
{
sql = "PRAGMA journal_mode=OFF";/* Create SQL statement */
rc = sqlite3_exec(db, sql, NULL, NULL, &zErrMsg);/* Execute SQL
statement */
if( rc != SQLITE_OK )
{
sqlite3_free(zErrMsg);
LOGGER_LOG_FATAL(LOG_CLASS, "Could not execute journal mode:
%d", rc);
l_nIntermediateResult = e_RETURNVALUE_Failure;
}
}
#endif
if ( e_RETURNVALUE_Success == l_nIntermediateResult)
{
sql ="CREATE TABLE Cars(Id INT, Name TEXT, Price INT);" ;/* Create
SQL statement */
rc = sqlite3_exec(db, sql, NULL, NULL, &zErrMsg);/* Execute SQL
statement */
if( rc != SQLITE_OK )
{
sqlite3_free(zErrMsg);
LOGGER_LOG_FATAL(LOG_CLASS, "Could not execute create table:
%d", rc);
l_nIntermediateResult = e_RETURNVALUE_Failure;
}
}
if ( e_RETURNVALUE_Success == l_nIntermediateResult)
{
sql = "INSERT INTO Cars VALUES(1, 'Audi', 52642);"/* Create SQL
statement */
"INSERT INTO Cars VALUES(2, 'Skoda', 9000);";
rc = sqlite3_exec(db, sql, NULL, NULL, &zErrMsg);/* Execute SQL
statement */
if( rc != SQLITE_OK )
{
sqlite3_free(zErrMsg);
LOGGER_LOG_FATAL(LOG_CLASS, "Could not execute insert: %d", rc);
l_nIntermediateResult = e_RETURNVALUE_Failure;
}
}
if ( e_RETURNVALUE_Success == l_nIntermediateResult )
{
sql = "SELECT * from Cars";/* Create SQL statement */
const char* data = "Callback function called";
rc = sqlite3_exec(db, sql, lclSqlCallback, (void *)data,
&zErrMsg);/* Execute SQL statement */
if( rc != SQLITE_OK )
{
sqlite3_free(zErrMsg);
LOGGER_LOG_FATAL(LOG_CLASS, "Could not execute select: %d", rc);
l_nIntermediateResult = e_RETURNVALUE_Failure;
}
}
if ( e_RETURNVALUE_Success == l_nIntermediateResult )
{
sqlite3_close(db);
}
}
Any suggestions about what could be going wrong (or when this magic header
should be written )
Thank you
Bram Peeters
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