DBD-SQLcipher
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#define osStat ((int(*)(const char*,struct stat*))aSyscall[4].pCurrent)
/*
** The DJGPP compiler environment looks mostly like Unix, but it
** lacks the fcntl() system call. So redefine fcntl() to be something
** that always succeeds. This means that locking does not occur under
** DJGPP. But it is DOS - what did you expect?
*/
#ifdef __DJGPP__
{ "fstat", 0, 0 },
#define osFstat(a,b,c) 0
#else
{ "fstat", (sqlite3_syscall_ptr)fstat, 0 },
#define osFstat ((int(*)(int,struct stat*))aSyscall[5].pCurrent)
#endif
{ "ftruncate", (sqlite3_syscall_ptr)ftruncate, 0 },
#define osFtruncate ((int(*)(int,off_t))aSyscall[6].pCurrent)
{ "fcntl", (sqlite3_syscall_ptr)fcntl, 0 },
#define osFcntl ((int(*)(int,int,...))aSyscall[7].pCurrent)
if( fd>=SQLITE_MINIMUM_FILE_DESCRIPTOR ) break;
osClose(fd);
sqlite3_log(SQLITE_WARNING,
"attempt to open \"%s\" as file descriptor %d", z, fd);
fd = -1;
if( osOpen("/dev/null", f, m)<0 ) break;
}
if( fd>=0 ){
if( m!=0 ){
struct stat statbuf;
if( osFstat(fd, &statbuf)==0
&& statbuf.st_size==0
&& (statbuf.st_mode&0777)!=m
){
osFchmod(fd, m);
}
}
#if defined(FD_CLOEXEC) && (!defined(O_CLOEXEC) || O_CLOEXEC==0)
osFcntl(fd, F_SETFD, osFcntl(fd, F_GETFD, 0) | FD_CLOEXEC);
#endif
}
** file descriptors opened on different file names.
**
** This means that we cannot use POSIX locks to synchronize file access
** among competing threads of the same process. POSIX locks will work fine
** to synchronize access for threads in separate processes, but not
** threads within the same process.
**
** To work around the problem, SQLite has to manage file locks internally
** on its own. Whenever a new database is opened, we have to find the
** specific inode of the database file (the inode is determined by the
** st_dev and st_ino fields of the stat structure that fstat() fills in)
** and check for locks already existing on that inode. When locks are
** created or removed, we have to look at our own internal record of the
** locks to see if another thread has previously set a lock on that same
** inode.
**
** (Aside: The use of inode numbers as unique IDs does not work on VxWorks.
** For VxWorks, we have to use the alternative unique ID system based on
** canonical filename and implemented in the previous division.)
**
** The sqlite3_file structure for POSIX is no longer just an integer file
struct unixFileId fileId; /* Lookup key for the unixInodeInfo */
struct stat statbuf; /* Low-level file information */
unixInodeInfo *pInode = 0; /* Candidate unixInodeInfo object */
assert( unixMutexHeld() );
/* Get low-level information about the file that we can used to
** create a unique name for the file.
*/
fd = pFile->h;
rc = osFstat(fd, &statbuf);
if( rc!=0 ){
pFile->lastErrno = errno;
#ifdef EOVERFLOW
if( pFile->lastErrno==EOVERFLOW ) return SQLITE_NOLFS;
#endif
return SQLITE_IOERR;
}
#ifdef __APPLE__
/* On OS X on an msdos filesystem, the inode number is reported
** in the header of every SQLite database. In this way, if there
** is a race condition such that another thread has already populated
** the first page of the database, no damage is done.
*/
if( statbuf.st_size==0 && (pFile->fsFlags & SQLITE_FSFLAGS_IS_MSDOS)!=0 ){
do{ rc = osWrite(fd, "S", 1); }while( rc<0 && errno==EINTR );
if( rc!=1 ){
pFile->lastErrno = errno;
return SQLITE_IOERR;
}
rc = osFstat(fd, &statbuf);
if( rc!=0 ){
pFile->lastErrno = errno;
return SQLITE_IOERR;
}
}
#endif
memset(&fileId, 0, sizeof(fileId));
fileId.dev = statbuf.st_dev;
#if OS_VXWORKS
** Issue sqlite3_log(SQLITE_WARNING,...) messages if anything is not right.
*/
static void verifyDbFile(unixFile *pFile){
struct stat buf;
int rc;
if( pFile->ctrlFlags & UNIXFILE_WARNED ){
/* One or more of the following warnings have already been issued. Do not
** repeat them so as not to clutter the error log */
return;
}
rc = osFstat(pFile->h, &buf);
if( rc!=0 ){
sqlite3_log(SQLITE_WARNING, "cannot fstat db file %s", pFile->zPath);
pFile->ctrlFlags |= UNIXFILE_WARNED;
return;
}
if( buf.st_nlink==0 && (pFile->ctrlFlags & UNIXFILE_DELETE)==0 ){
sqlite3_log(SQLITE_WARNING, "file unlinked while open: %s", pFile->zPath);
pFile->ctrlFlags |= UNIXFILE_WARNED;
return;
}
}
}
/*
** Determine the current size of a file in bytes
*/
static int unixFileSize(sqlite3_file *id, i64 *pSize){
int rc;
struct stat buf;
assert( id );
rc = osFstat(((unixFile*)id)->h, &buf);
SimulateIOError( rc=1 );
if( rc!=0 ){
((unixFile*)id)->lastErrno = errno;
return SQLITE_IOERR_FSTAT;
}
*pSize = buf.st_size;
/* When opening a zero-size database, the findInodeInfo() procedure
** writes a single byte into that file in order to work around a bug
** in the OS-X msdos filesystem. In order to avoid problems with upper
/*
** This function is called to handle the SQLITE_FCNTL_SIZE_HINT
** file-control operation. Enlarge the database to nBytes in size
** (rounded up to the next chunk-size). If the database is already
** nBytes or larger, this routine is a no-op.
*/
static int fcntlSizeHint(unixFile *pFile, i64 nByte){
if( pFile->szChunk>0 ){
i64 nSize; /* Required file size */
struct stat buf; /* Used to hold return values of fstat() */
if( osFstat(pFile->h, &buf) ) return SQLITE_IOERR_FSTAT;
nSize = ((nByte+pFile->szChunk-1) / pFile->szChunk) * pFile->szChunk;
if( nSize>(i64)buf.st_size ){
#if defined(HAVE_POSIX_FALLOCATE) && HAVE_POSIX_FALLOCATE
/* The code below is handling the return value of osFallocate()
** correctly. posix_fallocate() is defined to "returns zero on success,
** or an error number on failure". See the manpage for details. */
int err;
do{
memset(p, 0, sizeof(*p));
assert( pDbFd->pShm==0 );
/* Check to see if a unixShmNode object already exists. Reuse an existing
** one if present. Create a new one if necessary.
*/
unixEnterMutex();
pInode = pDbFd->pInode;
pShmNode = pInode->pShmNode;
if( pShmNode==0 ){
struct stat sStat; /* fstat() info for database file */
/* Call fstat() to figure out the permissions on the database file. If
** a new *-shm file is created, an attempt will be made to create it
** with the same permissions.
*/
if( osFstat(pDbFd->h, &sStat) && pInode->bProcessLock==0 ){
rc = SQLITE_IOERR_FSTAT;
goto shm_open_err;
}
#ifdef SQLITE_SHM_DIRECTORY
nShmFilename = sizeof(SQLITE_SHM_DIRECTORY) + 31;
#else
nShmFilename = 6 + (int)strlen(pDbFd->zPath);
#endif
pShmNode = sqlite3_malloc( sizeof(*pShmNode) + nShmFilename );
assert( pShmNode->pInode==pDbFd->pInode );
assert( pShmNode->h>=0 || pDbFd->pInode->bProcessLock==1 );
assert( pShmNode->h<0 || pDbFd->pInode->bProcessLock==0 );
/* Minimum number of regions required to be mapped. */
nReqRegion = ((iRegion+nShmPerMap) / nShmPerMap) * nShmPerMap;
if( pShmNode->nRegion<nReqRegion ){
char **apNew; /* New apRegion[] array */
int nByte = nReqRegion*szRegion; /* Minimum required file size */
struct stat sStat; /* Used by fstat() */
pShmNode->szRegion = szRegion;
if( pShmNode->h>=0 ){
/* The requested region is not mapped into this processes address space.
** Check to see if it has been allocated (i.e. if the wal-index file is
** large enough to contain the requested region).
*/
if( osFstat(pShmNode->h, &sStat) ){
rc = SQLITE_IOERR_SHMSIZE;
goto shmpage_out;
}
if( sStat.st_size<nByte ){
/* The requested memory region does not exist. If bExtend is set to
** false, exit early. *pp will be set to NULL and SQLITE_OK returned.
*/
if( !bExtend ){
goto shmpage_out;
*/
static int unixMapfile(unixFile *pFd, i64 nByte){
i64 nMap = nByte;
int rc;
assert( nMap>=0 || pFd->nFetchOut==0 );
if( pFd->nFetchOut>0 ) return SQLITE_OK;
if( nMap<0 ){
struct stat statbuf; /* Low-level file information */
rc = osFstat(pFd->h, &statbuf);
if( rc!=SQLITE_OK ){
return SQLITE_IOERR_FSTAT;
}
nMap = statbuf.st_size;
}
if( nMap>pFd->mmapSizeMax ){
nMap = pFd->mmapSizeMax;
}
if( nMap!=pFd->mmapSize ){
|| pLockingStyle == &nfsIoMethods
#endif
){
unixEnterMutex();
rc = findInodeInfo(pNew, &pNew->pInode);
if( rc!=SQLITE_OK ){
/* If an error occurred in findInodeInfo(), close the file descriptor
** immediately, before releasing the mutex. findInodeInfo() may fail
** in two scenarios:
**
** (a) A call to fstat() failed.
** (b) A malloc failed.
**
** Scenario (b) may only occur if the process is holding no other
** file descriptors open on the same file. If there were other file
** descriptors on this file, then no malloc would be required by
** findInodeInfo(). If this is the case, it is quite safe to close
** handle h - as it is guaranteed that no posix locks will be released
** by doing so.
**
** If scenario (a) caused the error then things are not so safe. The
** implicit assumption here is that if fstat() fails, things are in
** such bad shape that dropping a lock or two doesn't matter much.
*/
robust_close(pNew, h, __LINE__);
h = -1;
}
unixLeaveMutex();
}
#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
else if( pLockingStyle == &afpIoMethods ){
*/
static UnixUnusedFd *findReusableFd(const char *zPath, int flags){
UnixUnusedFd *pUnused = 0;
/* Do not search for an unused file descriptor on vxworks. Not because
** vxworks would not benefit from the change (it might, we're not sure),
** but because no way to test it is currently available. It is better
** not to risk breaking vxworks support for the sake of such an obscure
** feature. */
#if !OS_VXWORKS
struct stat sStat; /* Results of stat() call */
/* A stat() call may fail for various reasons. If this happens, it is
** almost certain that an open() call on the same path will also fail.
** For this reason, if an error occurs in the stat() call here, it is
** ignored and -1 is returned. The caller will try to open a new file
** descriptor on the same path, fail, and return an error to SQLite.
**
** Even if a subsequent open() call does succeed, the consequences of
** not searching for a reusable file descriptor are not dire. */
if( 0==osStat(zPath, &sStat) ){
unixInodeInfo *pInode;
unixEnterMutex();
pInode = inodeList;
uid_t *pUid, /* OUT: uid to set on the file */
gid_t *pGid /* OUT: gid to set on the file */
){
int rc = SQLITE_OK; /* Return Code */
*pMode = 0;
*pUid = 0;
*pGid = 0;
if( flags & (SQLITE_OPEN_WAL|SQLITE_OPEN_MAIN_JOURNAL) ){
char zDb[MAX_PATHNAME+1]; /* Database file path */
int nDb; /* Number of valid bytes in zDb */
struct stat sStat; /* Output of stat() on database file */
/* zPath is a path to a WAL or journal file. The following block derives
** the path to the associated database file from zPath. This block handles
** the following naming conventions:
**
** "<path to db>-journal"
** "<path to db>-wal"
** "<path to db>-journalNN"
** "<path to db>-walNN"
**
rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, lockType);
nTries ++;
if( rc==SQLITE_BUSY ){
/* If the lock failed (busy):
* 1st try: get the mod time of the conch, wait 0.5s and try again.
* 2nd try: fail if the mod time changed or host id is different, wait
* 10 sec and try again
* 3rd try: break the lock unless the mod time has changed.
*/
struct stat buf;
if( osFstat(conchFile->h, &buf) ){
pFile->lastErrno = errno;
return SQLITE_IOERR_LOCK;
}
if( nTries==1 ){
conchModTime = buf.st_mtimespec;
usleep(500000); /* wait 0.5 sec and try the lock again*/
continue;
}
}
writeSize = PROXY_PATHINDEX + strlen(&writeBuffer[PROXY_PATHINDEX]);
robust_ftruncate(conchFile->h, writeSize);
rc = unixWrite((sqlite3_file *)conchFile, writeBuffer, writeSize, 0);
fsync(conchFile->h);
/* If we created a new conch file (not just updated the contents of a
** valid conch file), try to match the permissions of the database
*/
if( rc==SQLITE_OK && createConch ){
struct stat buf;
int err = osFstat(pFile->h, &buf);
if( err==0 ){
mode_t cmode = buf.st_mode&(S_IRUSR|S_IWUSR | S_IRGRP|S_IWGRP |
S_IROTH|S_IWOTH);
/* try to match the database file R/W permissions, ignore failure */
#ifndef SQLITE_PROXY_DEBUG
osFchmod(conchFile->h, cmode);
#else
do{
rc = osFchmod(conchFile->h, cmode);
}while( rc==(-1) && errno==EINTR );
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