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Overview
| Comment: | Change the xShmSize() implementation in os_unix.c so that it will only increase and never decrease the size of a shared-memory segment. |
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| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | wal-refactor |
| Files: | files | file ages | folders |
| SHA1: |
149d2ae4a6fe2f86822f286d2a7092c5 |
| User & Date: | drh 2010-05-13 08:33:36 |
| Original Comment: | Change the xShmSize() implementation in os_unix.c so that it will only increase and never decrease the size of a shared-memory segment. |
Context
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2010-05-13
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| 08:53 | The refactored of VFS SHM primitives are now working so merge the wal-refactor branch back into the trunk. check-in: bce21c18 user: drh tags: trunk | |
| 08:33 | Change the xShmSize() implementation in os_unix.c so that it will only increase and never decrease the size of a shared-memory segment. Closed-Leaf check-in: 149d2ae4 user: drh tags: wal-refactor | |
| 07:08 | Fix for a segfault that can follow a malloc failure. check-in: 3cab9022 user: dan tags: wal-refactor | |
Changes
Changes to src/os_unix.c.
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){
unixFile *pDbFd = (unixFile*)fd;
unixShm *p = pDbFd->pShm;
unixShmFile *pFile = p->pFile;
int rc = SQLITE_OK;
struct stat sStat;
if( reqSize>=0 ){
reqSize = (reqSize + SQLITE_UNIX_SHM_INCR - 1)/SQLITE_UNIX_SHM_INCR;
reqSize *= SQLITE_UNIX_SHM_INCR;
rc = ftruncate(pFile->h, reqSize);
}
if( fstat(pFile->h, &sStat)==0 ){
*pNewSize = (int)sStat.st_size;
}else{
*pNewSize = 0;
rc = SQLITE_IOERR;
}
return rc;
}
/*
** Map the shared storage into memory. The minimum size of the
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){
unixFile *pDbFd = (unixFile*)fd;
unixShm *p = pDbFd->pShm;
unixShmFile *pFile = p->pFile;
int rc = SQLITE_OK;
struct stat sStat;
/* On a query, this loop runs once. When reqSize>=0, the loop potentially
** runs twice, except if the actual size is already greater than or equal
** to the requested size, reqSize is set to -1 on the first iteration and
** the loop only runs once.
*/
while( 1 ){
if( fstat(pFile->h, &sStat)==0 ){
*pNewSize = (int)sStat.st_size;
if( reqSize>=0 && reqSize<=(int)sStat.st_size ) break;
}else{
*pNewSize = 0;
rc = SQLITE_IOERR;
break;
}
if( reqSize<0 ) break;
reqSize = (reqSize + SQLITE_UNIX_SHM_INCR - 1)/SQLITE_UNIX_SHM_INCR;
reqSize *= SQLITE_UNIX_SHM_INCR;
rc = ftruncate(pFile->h, reqSize);
reqSize = -1;
}
return rc;
}
/*
** Map the shared storage into memory. The minimum size of the
|