#endif /* SQLITE_CHECK_PAGES */
/*
-** When this is called the journal file for pager pPager must be open.
-** This function attempts to read a super-journal file name from the
-** end of the file and, if successful, copies it into memory supplied
-** by the caller. See comments above writeSuperJournal() for the format
-** used to store a super-journal file name at the end of a journal file.
-**
-** zSuper must point to a buffer of at least nSuper bytes allocated by
-** the caller. This should be sqlite3_vfs.mxPathname+1 (to ensure there is
-** enough space to write the super-journal name). If the super-journal
-** name in the journal is longer than nSuper bytes (including a
-** nul-terminator), then this is handled as if no super-journal name
-** were present in the journal.
-**
-** If a super-journal file name is present at the end of the journal
-** file, then it is copied into the buffer pointed to by zSuper. A
-** nul-terminator byte is appended to the buffer following the
-** super-journal file name.
-**
-** If it is determined that no super-journal file name is present
-** zSuper[0] is set to 0 and SQLITE_OK returned.
-**
-** If an error occurs while reading from the journal file, an SQLite
-** error code is returned.
-*/
-static int readSuperJournal(sqlite3_file *pJrnl, char *zSuper, u64 nSuper){
+** Free a buffer allocated by the readSuperJournal() function.
+*/
+static void freeSuperJournal(char *zSuper){
+ if( zSuper ){
+ sqlite3_free(&zSuper[-4]);
+ }
+}
+
+/*
+** Parameter pJrnl is a file-handle open on a journal file. This function
+** attempts to read a super-journal file name from the end of the journal
+** file. If successful, it sets output parameter (*pzSuper) to point to a
+** buffer containing the super-journal name as a nul-terminated string.
+** The caller is responsible for freeing the buffer using freeSuperJournal().
+**
+** Refer to comments above writeSuperJournal() for the format used to store
+** a super-journal file name at the end of a journal file.
+**
+** Parameter nSuper is passed the maximum allowable size of the super journal
+** name in bytes. If the super-journal name in the journal is longer than
+** nSuper bytes (including a nul-terminator), then this is handled as if no
+** super-journal name were present in the journal.
+**
+** If there is no super-journal name at the end of pJrnl, (*pzSuper) is
+** set to 0 and SQLITE_OK is returned. Or, if an error occurs while reading
+** the super-journal name, an SQLite error code is returned and (*pzSuper)
+** is set to 0.
+*/
+static int readSuperJournal(sqlite3_file *pJrnl, u64 nSuper, char **pzSuper){
int rc; /* Return code */
u32 len; /* Length in bytes of super-journal name */
i64 szJ; /* Total size in bytes of journal file pJrnl */
u32 cksum; /* MJ checksum value read from journal */
- u32 u; /* Unsigned loop counter */
unsigned char aMagic[8]; /* A buffer to hold the magic header */
- zSuper[0] = '\0';
+ char *zOut = 0;
+ *pzSuper = 0;
if( SQLITE_OK!=(rc = sqlite3OsFileSize(pJrnl, &szJ))
|| szJ<16
|| SQLITE_OK!=(rc = read32bits(pJrnl, szJ-16, &len))
|| SQLITE_OK!=(rc = read32bits(pJrnl, szJ-12, &cksum))
|| SQLITE_OK!=(rc = sqlite3OsRead(pJrnl, aMagic, 8, szJ-8))
|| memcmp(aMagic, aJournalMagic, 8)
- || SQLITE_OK!=(rc = sqlite3OsRead(pJrnl, zSuper, len, szJ-16-len))
){
return rc;
}
- /* See if the checksum matches the super-journal name */
- for(u=0; u<len; u++){
- cksum -= zSuper[u];
- }
- if( cksum ){
- /* If the checksum doesn't add up, then one or more of the disk sectors
- ** containing the super-journal filename is corrupted. This means
- ** definitely roll back, so just return SQLITE_OK and report a (nul)
- ** super-journal filename.
- */
- len = 0;
+ zOut = (char*)sqlite3MallocZero(4 + len + 2);
+ if( !zOut ){
+ rc = SQLITE_NOMEM_BKPT;
+ }else{
+ zOut = &zOut[4];
+ if( SQLITE_OK==(rc = sqlite3OsRead(pJrnl, zOut, len, szJ-16-len)) ){
+ u32 u; /* Unsigned loop counter */
+ /* See if the checksum matches the super-journal name */
+ for(u=0; u<len; u++){
+ cksum -= zOut[u];
+ }
+ }
+ if( rc!=SQLITE_OK || cksum ){
+ /* If the checksum doesn't add up, then one or more of the disk sectors
+ ** containing the super-journal filename is corrupted. This means
+ ** definitely roll back, so just return SQLITE_OK and report a (nul)
+ ** super-journal filename. */
+ freeSuperJournal(zOut);
+ zOut = 0;
+ }
}
- zSuper[len] = '\0';
- zSuper[len+1] = '\0';
-
- return SQLITE_OK;
+
+ *pzSuper = zOut;
+ return rc;
}
/*
char *zSuperJournal = 0; /* Contents of super-journal file */
i64 nSuperJournal; /* Size of super-journal file */
char *zJournal; /* Pointer to one journal within MJ file */
- char *zSuperPtr; /* Space to hold super-journal filename */
char *zFree = 0; /* Free this buffer */
- i64 nSuperPtr; /* Amount of space allocated to zSuperPtr[] */
/* Allocate space for both the pJournal and pSuper file descriptors.
** If successful, open the super-journal file for reading.
*/
rc = sqlite3OsFileSize(pSuper, &nSuperJournal);
if( rc!=SQLITE_OK ) goto delsuper_out;
- nSuperPtr = 1 + (i64)pVfs->mxPathname;
- assert( nSuperJournal>=0 && nSuperPtr>0 );
- zFree = sqlite3Malloc(4 + nSuperJournal + 2 + nSuperPtr + 2);
+ assert( nSuperJournal>=0 );
+ zFree = sqlite3Malloc(4 + nSuperJournal + 2);
if( !zFree ){
rc = SQLITE_NOMEM_BKPT;
goto delsuper_out;
}
zFree[0] = zFree[1] = zFree[2] = zFree[3] = 0;
zSuperJournal = &zFree[4];
- zSuperPtr = &zSuperJournal[nSuperJournal+2];
rc = sqlite3OsRead(pSuper, zSuperJournal, (int)nSuperJournal, 0);
if( rc!=SQLITE_OK ) goto delsuper_out;
zSuperJournal[nSuperJournal] = 0;
goto delsuper_out;
}
if( exists ){
+ char *zSuperPtr = 0;
+
/* One of the journals pointed to by the super-journal exists.
** Open it and check if it points at the super-journal. If
** so, return without deleting the super-journal file.
goto delsuper_out;
}
- rc = readSuperJournal(pJournal, zSuperPtr, nSuperPtr);
+ rc = readSuperJournal(pJournal, 1+(u64)pVfs->mxPathname, &zSuperPtr);
sqlite3OsClose(pJournal);
if( rc!=SQLITE_OK ){
+ assert( zSuperPtr==0 );
goto delsuper_out;
}
- c = zSuperPtr[0]!=0 && strcmp(zSuperPtr, zSuper)==0;
+ c = zSuperPtr!=0 && strcmp(zSuperPtr, zSuper)==0;
+ freeSuperJournal(zSuperPtr);
if( c ){
/* We have a match. Do not delete the super-journal file. */
goto delsuper_out;
** If a super-journal file name is specified, but the file is not
** present on disk, then the journal is not hot and does not need to be
** played back.
- **
- ** TODO: Technically the following is an error because it assumes that
- ** buffer Pager.pTmpSpace is (mxPathname+1) bytes or larger. i.e. that
- ** ((pPager->pageSize+8) >= pPager->pVfs->mxPathname+1). Using os_unix.c,
- ** mxPathname is 512, which is the same as the minimum allowable value
- ** for pageSize, and so this assumption holds. But it might not for some
- ** custom VFS. */
- zSuper = pPager->pTmpSpace;
- rc = readSuperJournal(pPager->jfd, zSuper, 1+(i64)pPager->pVfs->mxPathname);
- if( rc==SQLITE_OK && zSuper[0] ){
+ */
+ rc = readSuperJournal(pPager->jfd, 1+(i64)pPager->pVfs->mxPathname, &zSuper);
+ if( rc==SQLITE_OK && zSuper ){
rc = sqlite3OsAccess(pVfs, zSuper, SQLITE_ACCESS_EXISTS, &res);
}
- zSuper = 0;
if( rc!=SQLITE_OK || !res ){
goto end_playback;
}
*/
pPager->changeCountDone = pPager->tempFile;
- if( rc==SQLITE_OK ){
- /* Leave 4 bytes of space before the super-journal filename in memory.
- ** This is because it may end up being passed to sqlite3OsOpen(), in
- ** which case it requires 4 0x00 bytes in memory immediately before
- ** the filename. */
- zSuper = &pPager->pTmpSpace[4];
- rc = readSuperJournal(pPager->jfd, zSuper, 1+(i64)pPager->pVfs->mxPathname);
- testcase( rc!=SQLITE_OK );
- }
if( rc==SQLITE_OK
&& (pPager->eState>=PAGER_WRITER_DBMOD || pPager->eState==PAGER_OPEN)
){
rc = sqlite3PagerSync(pPager, 0);
}
if( rc==SQLITE_OK ){
- rc = pager_end_transaction(pPager, zSuper[0]!='\0', 0);
+ rc = pager_end_transaction(pPager, zSuper!=0, 0);
testcase( rc!=SQLITE_OK );
}
- if( rc==SQLITE_OK && zSuper[0] && res ){
+ if( rc==SQLITE_OK && zSuper && res ){
/* If there was a super-journal and this routine will return success,
** see if it is possible to delete the super-journal.
*/
- assert( zSuper==&pPager->pTmpSpace[4] );
- memset(pPager->pTmpSpace, 0, 4);
+ assert( memcmp(&zSuper[-4], "\0\0\0\0", 4)==0 );
rc = pager_delsuper(pPager, zSuper);
testcase( rc!=SQLITE_OK );
}
** back a journal created by a process with a different sector size
** value. Reset it to the correct value for this process.
*/
+ freeSuperJournal(zSuper);
setSectorSize(pPager);
return rc;
}
projects / thirdparty / sqlite.git / commitdiff
