-C Apply\s[b9b11855e8]\s(the\salternate\sfix\sto\s[fc62af4523])\sto\sthe\strunk.
-D 2010-06-17T17:05:54
+-----BEGIN PGP SIGNED MESSAGE-----
+Hash: SHA1
+
+C Change\sthe\sunix\sVFS\sto\salways\sallocate\sshared-memory\susing\sa\sfile\sin\sthe\nsame\sdirectory\sas\sthe\sdatabase.\s\sOtherwise,\sa\schroot\smight\scause\sdifferent\nprocesses\sto\suse\sdifferent\sshared\smemory\sfiles\sresulting\sin\sdatabase\ncorruption.
+D 2010-06-19T15:10:10
F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
F Makefile.in a5cad1f8f3e021356bfcc6c77dc16f6f1952bbc3
F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
F src/os.h d7775504a51e6e0d40315aa427b3e229ff9ff9ca
F src/os_common.h a8f95b81eca8a1ab8593d23e94f8a35f35d4078f
F src/os_os2.c 665876d5eec7585226b0a1cf5e18098de2b2da19
-F src/os_unix.c ae173c9f6afaa58b2833a1c95c6cd32021755c42
+F src/os_unix.c a76d1952ac7984574701c48b665220b871c5c9a5
F src/os_win.c dfde7d33c446e89dd9a277c036f2c4cc564b3138
F src/pager.c 4fe451d68950002eb985e6325d666ab54956a37f
F src/pager.h ca1f23c0cf137ac26f8908df2427c8b308361efd
F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
-P 7c3a86b9c7e2a35ce755c32b38e911e79d843fad
-R 1e4481b965cd36ec30ba83a04296f9cc
-U dan
-Z b00e14e0e21b5f60f6931c141403c159
+P 9a949a3a5c32b8bfbb94e10e18d050ec80a25553
+R acdbeeb43afddd9408962cb351e87aec
+U drh
+Z 2d4cd5d2db2524a9b5137cfeafb22e1e
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}
}
-/* Forward reference */
-static const char *unixTempFileDir(int);
-
/*
-** Open a shared-memory area. This particular implementation uses
-** mmapped files.
-**
-** zName is a filename used to identify the shared-memory area. The
-** implementation does not (and perhaps should not) use this name
-** directly, but rather use it as a template for finding an appropriate
-** name for the shared-memory storage. In this implementation, the
-** string "-index" is appended to zName and used as the name of the
-** mmapped file.
+** Open a shared-memory area associated with open database file fd.
+** This particular implementation uses mmapped files.
+**
+** The file used to implement shared-memory is in the same directory
+** as the open database file and has the same name as the open database
+** file with the "-shm" suffix added. For example, if the database file
+** is "/home/user1/config.db" then the file that is created and mmapped
+** for shared memory will be called "/home/user1/config.db-shm". We
+** experimented with using files in /dev/tmp or an some other tmpfs mount.
+** But if a file in a different directory from the database file is used,
+** then differing access permissions or a chroot() might cause two different
+** processes on the same database to end up using different files for
+** shared memory - meaning that their memory would not really be shared -
+** resulting in database corruption.
**
** When opening a new shared-memory file, if no other instances of that
** file are currently open, in this process or in other processes, then
int rc; /* Result code */
struct unixFile *pDbFd; /* Underlying database file */
unixInodeInfo *pInode; /* The inode of fd */
- const char *zTempDir; /* Directory for temporary files */
- int nTempDir; /* Size of the zTempDir string */
+ char *zShmFilename; /* Name of the file used for SHM */
+ int nShmFilename; /* Size of the SHM filename in bytes */
/* Allocate space for the new sqlite3_shm object.
*/
pInode = pDbFd->pInode;
pShmNode = pInode->pShmNode;
if( pShmNode==0 ){
- zTempDir = unixTempFileDir(1);
- if( zTempDir==0 ){
- unixLeaveMutex();
- sqlite3_free(p);
- return SQLITE_CANTOPEN_NOTEMPDIR;
- }
- nTempDir = strlen(zTempDir);
- pShmNode = sqlite3_malloc( sizeof(*pShmNode) + nTempDir + 50 );
+ nShmFilename = 5 + (int)strlen(pDbFd->zPath);
+ pShmNode = sqlite3_malloc( sizeof(*pShmNode) + nShmFilename );
if( pShmNode==0 ){
rc = SQLITE_NOMEM;
goto shm_open_err;
}
memset(pShmNode, 0, sizeof(*pShmNode));
- pShmNode->zFilename = (char*)&pShmNode[1];
- sqlite3_snprintf(nTempDir+50, pShmNode->zFilename,
- "%s/sqlite-wi-%x-%x", zTempDir,
- (u32)pInode->fileId.dev, (u32)pInode->fileId.ino);
+ zShmFilename = pShmNode->zFilename = (char*)&pShmNode[1];
+ sqlite3_snprintf(nShmFilename, zShmFilename, "%s-shm", pDbFd->zPath);
pShmNode->h = -1;
pDbFd->pInode->pShmNode = pShmNode;
pShmNode->pInode = pDbFd->pInode;
goto shm_open_err;
}
- pShmNode->h = open(pShmNode->zFilename, O_RDWR|O_CREAT, 0664);
+ pShmNode->h = open(zShmFilename, O_RDWR|O_CREAT, 0664);
if( pShmNode->h<0 ){
rc = SQLITE_CANTOPEN_BKPT;
goto shm_open_err;
** Return the name of a directory in which to put temporary files.
** If no suitable temporary file directory can be found, return NULL.
*/
-static const char *unixTempFileDir(int allowShm){
+static const char *unixTempFileDir(void){
static const char *azDirs[] = {
0,
0,
azDirs[0] = sqlite3_temp_directory;
if( !azDirs[1] ) azDirs[1] = getenv("TMPDIR");
-
- if( allowShm ){
- zDir = "/dev/shm";
- i = 2; /* Skip the app-defined temp locations for shared-memory */
- }else{
- zDir = azDirs[0];
- i = 1;
- }
- for(; i<sizeof(azDirs)/sizeof(azDirs[0]); zDir=azDirs[i++]){
+ for(i==0; i<sizeof(azDirs)/sizeof(azDirs[0]); zDir=azDirs[i++]){
if( zDir==0 ) continue;
if( stat(zDir, &buf) ) continue;
if( !S_ISDIR(buf.st_mode) ) continue;
- if( !allowShm && access(zDir, 07) ) continue;
+ if( access(zDir, 07) ) continue;
break;
}
return zDir;
*/
SimulateIOError( return SQLITE_IOERR );
- zDir = unixTempFileDir(0);
+ zDir = unixTempFileDir();
if( zDir==0 ) zDir = ".";
/* Check that the output buffer is large enough for the temporary file
projects / thirdparty / sqlite.git / commitdiff
