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Make sure the antipenultimate character of master-journal filenames is a "9"

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in order to avoid collisions with other files in 8+3 filename mode.  Also,
limit the number of attempts at finding a unique master-journal filename.

FossilOrigin-Name: 34a0483605d36e6cf03065ed0df33fb1f7c8a272
This commit is contained in:
drh
2011-12-16 00:33:04 +00:00
parent e712b5823e
commit f580860f51
4 changed files with 21 additions and 10 deletions
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12
src/vdbeaux.c
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@@ -1824,16 +1824,26 @@ static int vdbeCommit(sqlite3 *db, Vdbe *p){
sqlite3_file *pMaster = 0;
i64 offset = 0;
int res;
int retryCount = 0;
/* Select a master journal file name */
do {
u32 iRandom;
if( retryCount++>100 ){
sqlite3_log(SQLITE_FULL, "cannot create a master journal filename");
rc = SQLITE_FULL;
break;
}
sqlite3DbFree(db, zMaster);
sqlite3_randomness(sizeof(iRandom), &iRandom);
zMaster = sqlite3MPrintf(db, "%s-mj%08X", zMainFile, iRandom&0x7fffffff);
zMaster = sqlite3MPrintf(db, "%s-mj%06X9%02X", zMainFile,
(iRandom>>8)&0xffffff, iRandom&0xff);
if( !zMaster ){
return SQLITE_NOMEM;
}
/* The antipenultimate character of the master journal name must
** be "9" to avoid name collisions when using 8+3 filenames. */
assert( zMaster[strlen(zMaster)-3]=='9' );
sqlite3FileSuffix3(zMainFile, zMaster);
rc = sqlite3OsAccess(pVfs, zMaster, SQLITE_ACCESS_EXISTS, &res);
}while( rc==SQLITE_OK && res );