--- /dev/null
+/*
+** 2020-04-20
+**
+** The author disclaims copyright to this source code. In place of
+** a legal notice, here is a blessing:
+**
+** May you do good and not evil.
+** May you find forgiveness for yourself and forgive others.
+** May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file implements a VFS shim that writes a checksum on each page
+** of an SQLite database file. When reading pages, the checksum is verified
+** and an error is raised if the checksum is incorrect.
+**
+** COMPILING
+**
+** This extension requires SQLite 3.32.0 or later. It uses the
+** sqlite3_database_file_object() interface which was added in
+** version 3.32.0, so it will not link with an earlier version of
+** SQLite.
+**
+** To build this extension as a separately loaded shared library or
+** DLL, use compiler command-lines similar to the following:
+**
+** (linux) gcc -fPIC -shared cksumvfs.c -o cksumvfs.so
+** (mac) clang -fPIC -dynamiclib cksumvfs.c -o cksumvfs.dylib
+** (windows) cl cksumvfs.c -link -dll -out:cksumvfs.dll
+**
+** You may want to add additional compiler options, of course,
+** according to the needs of your project.
+**
+** If you want to statically link this extension with your product,
+** then compile it like any other C-language module but add the
+** "-DSQLITE_CKSUMVFS_STATIC" option so that this module knows that
+** it is being statically linked rather than dynamically linked
+**
+** LOADING
+**
+** To load this extension as a shared library, you first have to
+** bring up a dummy SQLite database connection to use as the argument
+** to the sqlite3_load_extension() API call. Then you invoke the
+** sqlite3_load_extension() API and shutdown the dummy database
+** connection. All subsequent database connections that are opened
+** will include this extension. For example:
+**
+** sqlite3 *db;
+** sqlite3_open(":memory:", &db);
+** sqlite3_load_extention(db, "./cksumvfs");
+** sqlite3_close(db);
+**
+** If this extension is compiled with -DSQLITE_CKSUMVFS_STATIC and
+** statically linked against the application, initialize it using
+** a single API call as follows:
+**
+** sqlite3_cksumvfs_init();
+**
+** Cksumvfs is a VFS Shim. When loaded, "cksmvfs" becomes the new
+** default VFS and it uses the prior default VFS as the next VFS
+** down in the stack. This is normally what you want. However, it
+** complex situations where multiple VFS shims are being loaded,
+** it might be important to ensure that cksumvfs is loaded in the
+** correct order so that it sequences itself into the default VFS
+** Shim stack in the right order.
+**
+** USING
+**
+** Open database connections using the sqlite3_open() or
+** sqlite3_open_v2() interfaces, as normal. Ordinary database files
+** (without a checksum) will operate normally. Databases with
+** checksums will return an SQLITE_CORRUPT error if a page is
+** encountered that contains an invalid checksum.
+**
+** Checksumming only works on databases that have a reserve-bytes
+** value of exactly 8. The default value for reserve-bytes is 0.
+** Hence, newly created database files will omit the checksum by
+** default. To create a database that includes a checksum, change
+** the reserve-bytes value to 8 by runing:
+**
+** int n = 8;
+** sqlite3_file_control(db, 0, SQLITE_FCNTL_RESERVED_BYTES, &n);
+**
+** If you do this immediately after creating a new database file,
+** before anything else has been written into the file, then that
+** might be all that you need to do. Otherwise, the API call
+** above should be followed by:
+**
+** sqlite3_exec(db, "VACUUM", 0, 0, 0);
+**
+** It never hurts to run the VACUUM, even if you don't need it.
+** If the database is in WAL mode, you should shutdown and
+** reopen all database connections before continuing.
+**
+** From the CLI, use the ".filectrl reserve_bytes 8" command,
+** followed by "VACUUM;".
+**
+** Note that SQLite allows the number of reserve-bytes to be
+** increased but not decreased. So if a database file already
+** has a reserve-bytes value greater than 8, there is no way to
+** activate checksumming on that database, other than to dump
+** and restore the database file. Note also that other extensions
+** might also make use of the reserve-bytes. Checksumming will
+** be incompatible with those other extensions.
+**
+** VERIFICATION OF CHECKSUMS
+**
+** If any checksum is incorrect, the "PRAGMA quick_check" command
+** will find it. To verify that checksums are actually enabled
+** and running, use the following query:
+**
+** SELECT count(*), verify_checksum(data)
+** FROM sqlite_dbpage
+** GROUP BY 2;
+**
+** There are three possible outputs form the verify_checksum()
+** function: 1, 0, and NULL. 1 is returned if the checksum is
+** correct. 0 is returned if the checksum is incorrect. NULL
+** is returned if the page is unreadable. If checksumming is
+** enabled, the read will fail if the checksum is wrong, so the
+** usual result from verify_checksum() on a bad checksum is NULL.
+**
+** If everything is OK, the query above should return a single
+** row where the second column is 1. Any other result indicates
+** either that there is a checksum error, or checksum validation
+** is disabled.
+**
+** CONTROLLING CHECKSUM VERIFICATION
+**
+** The cksumvfs extension implements a new PRAGMA statement that can
+** be used to disable, re-enable, or query the status of checksum
+** verification:
+**
+** PRAGMA checksum_verification; -- query status
+** PRAGMA checksum_verification=OFF; -- disable verification
+** PRAGMA checksum_verification=ON; -- re-enable verification
+**
+** The "checksum_verification" pragma will return "1" (true) or "0"
+** (false) if checksum verification is enabled or disabled, respectively.
+** "Verification" in this context means the feature that causes
+** SQLITE_CORRUPT errors if a checksum mismatch is detected while
+** reading. Checksums are always kept up-to-date as long as the
+** reserve-bytes value of the database is 8, regardless of the setting
+** of this pragma. Checksum verification can be disabled (for example)
+** to do forensic analysis of a database that has previously reported
+** a checksum error.
+**
+** The "checksum_verification" pragma will always respond with "0" if
+** the database file does not have a reserve-bytes value of 8. The
+** pragma will return no rows at all if the cksumvfs extension is
+** not loaded.
+**
+** IMPLEMENTATION NOTES
+**
+** The checksum is stored in the last 8 bytes of each page. This
+** module only operates if the "bytes of reserved space on each page"
+** value at offset 20 the SQLite database header is exactly 8. If
+** the reserved-space value is not 8, this module is a no-op.
+*/
+#ifdef SQLITE_CKSUMVFS_STATIC
+# include "sqlite3.h"
+#else
+# include "sqlite3ext.h"
+ SQLITE_EXTENSION_INIT1
+#endif
+#include <string.h>
+#include <assert.h>
+
+
+/*
+** Forward declaration of objects used by this utility
+*/
+typedef struct sqlite3_vfs CksmVfs;
+typedef struct CksmFile CksmFile;
+
+/*
+** Useful datatype abbreviations
+*/
+#if !defined(SQLITE_CORE)
+ typedef unsigned char u8;
+ typedef unsigned int u32;
+#endif
+
+/* Access to a lower-level VFS that (might) implement dynamic loading,
+** access to randomness, etc.
+*/
+#define ORIGVFS(p) ((sqlite3_vfs*)((p)->pAppData))
+#define ORIGFILE(p) ((sqlite3_file*)(((CksmFile*)(p))+1))
+
+/* An open file */
+struct CksmFile {
+ sqlite3_file base; /* IO methods */
+ char computeCksm; /* True to compute checksums.
+ ** Always true if reserve size is 8. */
+ char verifyCksm; /* True to verify checksums */
+ char isWal; /* True if processing a WAL file */
+ CksmFile *pPartner; /* Ptr from WAL to main-db, or from main-db to WAL */
+};
+
+/*
+** Methods for CksmFile
+*/
+static int cksmClose(sqlite3_file*);
+static int cksmRead(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
+static int cksmWrite(sqlite3_file*,const void*,int iAmt, sqlite3_int64 iOfst);
+static int cksmTruncate(sqlite3_file*, sqlite3_int64 size);
+static int cksmSync(sqlite3_file*, int flags);
+static int cksmFileSize(sqlite3_file*, sqlite3_int64 *pSize);
+static int cksmLock(sqlite3_file*, int);
+static int cksmUnlock(sqlite3_file*, int);
+static int cksmCheckReservedLock(sqlite3_file*, int *pResOut);
+static int cksmFileControl(sqlite3_file*, int op, void *pArg);
+static int cksmSectorSize(sqlite3_file*);
+static int cksmDeviceCharacteristics(sqlite3_file*);
+static int cksmShmMap(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
+static int cksmShmLock(sqlite3_file*, int offset, int n, int flags);
+static void cksmShmBarrier(sqlite3_file*);
+static int cksmShmUnmap(sqlite3_file*, int deleteFlag);
+static int cksmFetch(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
+static int cksmUnfetch(sqlite3_file*, sqlite3_int64 iOfst, void *p);
+
+/*
+** Methods for CksmVfs
+*/
+static int cksmOpen(sqlite3_vfs*, const char *, sqlite3_file*, int , int *);
+static int cksmDelete(sqlite3_vfs*, const char *zName, int syncDir);
+static int cksmAccess(sqlite3_vfs*, const char *zName, int flags, int *);
+static int cksmFullPathname(sqlite3_vfs*, const char *zName, int, char *zOut);
+static void *cksmDlOpen(sqlite3_vfs*, const char *zFilename);
+static void cksmDlError(sqlite3_vfs*, int nByte, char *zErrMsg);
+static void (*cksmDlSym(sqlite3_vfs *pVfs, void *p, const char*zSym))(void);
+static void cksmDlClose(sqlite3_vfs*, void*);
+static int cksmRandomness(sqlite3_vfs*, int nByte, char *zOut);
+static int cksmSleep(sqlite3_vfs*, int microseconds);
+static int cksmCurrentTime(sqlite3_vfs*, double*);
+static int cksmGetLastError(sqlite3_vfs*, int, char *);
+static int cksmCurrentTimeInt64(sqlite3_vfs*, sqlite3_int64*);
+static int cksmSetSystemCall(sqlite3_vfs*, const char*,sqlite3_syscall_ptr);
+static sqlite3_syscall_ptr cksmGetSystemCall(sqlite3_vfs*, const char *z);
+static const char *cksmNextSystemCall(sqlite3_vfs*, const char *zName);
+
+static sqlite3_vfs cksm_vfs = {
+ 3, /* iVersion (set when registered) */
+ 0, /* szOsFile (set when registered) */
+ 1024, /* mxPathname */
+ 0, /* pNext */
+ "cksmvfs", /* zName */
+ 0, /* pAppData (set when registered) */
+ cksmOpen, /* xOpen */
+ cksmDelete, /* xDelete */
+ cksmAccess, /* xAccess */
+ cksmFullPathname, /* xFullPathname */
+ cksmDlOpen, /* xDlOpen */
+ cksmDlError, /* xDlError */
+ cksmDlSym, /* xDlSym */
+ cksmDlClose, /* xDlClose */
+ cksmRandomness, /* xRandomness */
+ cksmSleep, /* xSleep */
+ cksmCurrentTime, /* xCurrentTime */
+ cksmGetLastError, /* xGetLastError */
+ cksmCurrentTimeInt64, /* xCurrentTimeInt64 */
+ cksmSetSystemCall, /* xSetSystemCall */
+ cksmGetSystemCall, /* xGetSystemCall */
+ cksmNextSystemCall /* xNextSystemCall */
+};
+
+static const sqlite3_io_methods cksm_io_methods = {
+ 3, /* iVersion */
+ cksmClose, /* xClose */
+ cksmRead, /* xRead */
+ cksmWrite, /* xWrite */
+ cksmTruncate, /* xTruncate */
+ cksmSync, /* xSync */
+ cksmFileSize, /* xFileSize */
+ cksmLock, /* xLock */
+ cksmUnlock, /* xUnlock */
+ cksmCheckReservedLock, /* xCheckReservedLock */
+ cksmFileControl, /* xFileControl */
+ cksmSectorSize, /* xSectorSize */
+ cksmDeviceCharacteristics, /* xDeviceCharacteristics */
+ cksmShmMap, /* xShmMap */
+ cksmShmLock, /* xShmLock */
+ cksmShmBarrier, /* xShmBarrier */
+ cksmShmUnmap, /* xShmUnmap */
+ cksmFetch, /* xFetch */
+ cksmUnfetch /* xUnfetch */
+};
+
+/* Do byte swapping on a unsigned 32-bit integer */
+#define BYTESWAP32(x) ( \
+ (((x)&0x000000FF)<<24) + (((x)&0x0000FF00)<<8) \
+ + (((x)&0x00FF0000)>>8) + (((x)&0xFF000000)>>24) \
+)
+
+/* Compute a checksum on a buffer */
+static void cksmCompute(
+ u8 *a, /* Content to be checksummed */
+ int nByte, /* Bytes of content in a[]. Must be a multiple of 8. */
+ u8 *aOut /* OUT: Final 8-byte checksum value output */
+){
+ u32 s1 = 0, s2 = 0;
+ u32 *aData = (u32*)a;
+ u32 *aEnd = (u32*)&a[nByte];
+ u32 x = 1;
+
+ assert( nByte>=8 );
+ assert( (nByte&0x00000007)==0 );
+ assert( nByte<=65536 );
+
+ if( 1 == *(u8*)&x ){
+ /* Little-endian */
+ do {
+ s1 += *aData++ + s2;
+ s2 += *aData++ + s1;
+ }while( aData<aEnd );
+ }else{
+ /* Big-endian */
+ do {
+ s1 += BYTESWAP32(aData[0]) + s2;
+ s2 += BYTESWAP32(aData[1]) + s1;
+ aData += 2;
+ }while( aData<aEnd );
+ s1 = BYTESWAP32(s1);
+ s2 = BYTESWAP32(s2);
+ }
+ memcpy(aOut, &s1, 4);
+ memcpy(aOut+4, &s2, 4);
+}
+
+/*
+** SQL function: verify_checksum(BLOB)
+**
+** Return 0 or 1 if the checksum is invalid or valid. Or return
+** NULL if the input is not a BLOB that is the right size for a
+** database page.
+*/
+static void cksmVerifyFunc(
+ sqlite3_context *context,
+ int argc,
+ sqlite3_value **argv
+){
+ int nByte;
+ u8 *data;
+ u8 cksum[8];
+ data = (u8*)sqlite3_value_blob(argv[0]);
+ if( data==0 ) return;
+ if( sqlite3_value_type(argv[0])!=SQLITE_BLOB ) return;
+ nByte = sqlite3_value_bytes(argv[0]);
+ if( nByte<512 || nByte>65536 || (nByte & (nByte-1))!=0 ) return;
+ cksmCompute(data, nByte-8, cksum);
+ sqlite3_result_int(context, memcmp(data+nByte-8,cksum,8)==0);
+}
+
+/*
+** Close a cksm-file.
+*/
+static int cksmClose(sqlite3_file *pFile){
+ CksmFile *p = (CksmFile *)pFile;
+ if( p->pPartner ){
+ assert( p->pPartner->pPartner==p );
+ p->pPartner->pPartner = 0;
+ p->pPartner = 0;
+ }
+ pFile = ORIGFILE(pFile);
+ return pFile->pMethods->xClose(pFile);
+}
+
+/*
+** Read data from a cksm-file.
+*/
+static int cksmRead(
+ sqlite3_file *pFile,
+ void *zBuf,
+ int iAmt,
+ sqlite_int64 iOfst
+){
+ int rc;
+ CksmFile *p = (CksmFile *)pFile;
+ pFile = ORIGFILE(pFile);
+ rc = pFile->pMethods->xRead(pFile, zBuf, iAmt, iOfst);
+ if( rc==SQLITE_OK ){
+ if( iOfst==0 && iAmt>=100 && memcmp(zBuf,"SQLite format 3",16)==0 ){
+ u8 *d = (u8*)zBuf;
+ char hasCorrectReserveSize = (d[20]==8);
+ if( hasCorrectReserveSize!=p->computeCksm ){
+ p->computeCksm = p->verifyCksm = hasCorrectReserveSize;
+ }
+ }
+ /* Verify the checksum if (1) the size seems appropriate for a database
+ ** page, and if (2) checksum verification is enabled. But (3) do not
+ ** verify the checksums on a WAL page if the main database file
+ ** has subsequently turned off checksums.
+ */
+ if( iAmt>=512 /* (1) */
+ && p->verifyCksm /* (2) */
+ && (!p->isWal || (p->pPartner!=0 && p->pPartner->verifyCksm)) /* (3) */
+ ){
+ u8 cksum[8];
+ cksmCompute((u8*)zBuf, iAmt-8, cksum);
+ if( memcmp(zBuf+iAmt-8, cksum, 8)!=0 ){
+ rc = SQLITE_CORRUPT;
+ }
+ }
+ }
+ return rc;
+}
+
+/*
+** Write data to a cksm-file.
+*/
+static int cksmWrite(
+ sqlite3_file *pFile,
+ const void *zBuf,
+ int iAmt,
+ sqlite_int64 iOfst
+){
+ CksmFile *p = (CksmFile *)pFile;
+ pFile = ORIGFILE(pFile);
+ if( iOfst==0 && iAmt>=100 && memcmp(zBuf,"SQLite format 3",16)==0 ){
+ u8 *d = (u8*)zBuf;
+ char hasCorrectReserveSize = (d[20]==8);
+ if( hasCorrectReserveSize!=p->computeCksm ){
+ p->computeCksm = p->verifyCksm = hasCorrectReserveSize;
+ }
+ }
+ /* If the write size is appropriate for a database page and if
+ ** checksums where ever enabled, then it will be safe to compute
+ ** the checksums. The reserve byte size might have increased, but
+ ** it will never decrease. And because it cannot decrease, the
+ ** checksum will not overwrite anything.
+ */
+ if( iAmt>=512 && p->computeCksm ){
+ cksmCompute((u8*)zBuf, iAmt-8, ((u8*)zBuf)+iAmt-8);
+ }
+ return pFile->pMethods->xWrite(pFile, zBuf, iAmt, iOfst);
+}
+
+/*
+** Truncate a cksm-file.
+*/
+static int cksmTruncate(sqlite3_file *pFile, sqlite_int64 size){
+ pFile = ORIGFILE(pFile);
+ return pFile->pMethods->xTruncate(pFile, size);
+}
+
+/*
+** Sync a cksm-file.
+*/
+static int cksmSync(sqlite3_file *pFile, int flags){
+ pFile = ORIGFILE(pFile);
+ return pFile->pMethods->xSync(pFile, flags);
+}
+
+/*
+** Return the current file-size of a cksm-file.
+*/
+static int cksmFileSize(sqlite3_file *pFile, sqlite_int64 *pSize){
+ CksmFile *p = (CksmFile *)pFile;
+ pFile = ORIGFILE(p);
+ return pFile->pMethods->xFileSize(pFile, pSize);
+}
+
+/*
+** Lock a cksm-file.
+*/
+static int cksmLock(sqlite3_file *pFile, int eLock){
+ pFile = ORIGFILE(pFile);
+ return pFile->pMethods->xLock(pFile, eLock);
+}
+
+/*
+** Unlock a cksm-file.
+*/
+static int cksmUnlock(sqlite3_file *pFile, int eLock){
+ pFile = ORIGFILE(pFile);
+ return pFile->pMethods->xUnlock(pFile, eLock);
+}
+
+/*
+** Check if another file-handle holds a RESERVED lock on a cksm-file.
+*/
+static int cksmCheckReservedLock(sqlite3_file *pFile, int *pResOut){
+ pFile = ORIGFILE(pFile);
+ return pFile->pMethods->xCheckReservedLock(pFile, pResOut);
+}
+
+/*
+** File control method. For custom operations on a cksm-file.
+*/
+static int cksmFileControl(sqlite3_file *pFile, int op, void *pArg){
+ int rc;
+ CksmFile *p = (CksmFile*)pFile;
+ pFile = ORIGFILE(pFile);
+ if( op==SQLITE_FCNTL_PRAGMA ){
+ char **azArg = (char**)pArg;
+ assert( azArg[1]!=0 );
+ if( strcmp(azArg[1],"checksum_verification")==0 ){
+ char *zArg = azArg[2];
+ if( zArg!=0 ){
+ if( (zArg[0]>='1' && zArg[0]<='9')
+ || sqlite3_strlike("enable%",zArg,0)==0
+ || sqlite3_stricmp("yes",zArg)==0
+ || sqlite3_stricmp("on",zArg)==0
+ ){
+ p->verifyCksm = p->computeCksm;
+ }else{
+ p->verifyCksm = 0;
+ }
+ }
+ azArg[0] = sqlite3_mprintf("%d",p->verifyCksm);
+ return SQLITE_OK;
+ }
+ }
+ rc = pFile->pMethods->xFileControl(pFile, op, pArg);
+ if( rc==SQLITE_OK && op==SQLITE_FCNTL_VFSNAME ){
+ *(char**)pArg = sqlite3_mprintf("cksm/%z", *(char**)pArg);
+ }
+ return rc;
+}
+
+/*
+** Return the sector-size in bytes for a cksm-file.
+*/
+static int cksmSectorSize(sqlite3_file *pFile){
+ pFile = ORIGFILE(pFile);
+ return pFile->pMethods->xSectorSize(pFile);
+}
+
+/*
+** Return the device characteristic flags supported by a cksm-file.
+*/
+static int cksmDeviceCharacteristics(sqlite3_file *pFile){
+ pFile = ORIGFILE(pFile);
+ return pFile->pMethods->xDeviceCharacteristics(pFile);
+}
+
+/* Create a shared memory file mapping */
+static int cksmShmMap(
+ sqlite3_file *pFile,
+ int iPg,
+ int pgsz,
+ int bExtend,
+ void volatile **pp
+){
+ pFile = ORIGFILE(pFile);
+ return pFile->pMethods->xShmMap(pFile,iPg,pgsz,bExtend,pp);
+}
+
+/* Perform locking on a shared-memory segment */
+static int cksmShmLock(sqlite3_file *pFile, int offset, int n, int flags){
+ pFile = ORIGFILE(pFile);
+ return pFile->pMethods->xShmLock(pFile,offset,n,flags);
+}
+
+/* Memory barrier operation on shared memory */
+static void cksmShmBarrier(sqlite3_file *pFile){
+ pFile = ORIGFILE(pFile);
+ pFile->pMethods->xShmBarrier(pFile);
+}
+
+/* Unmap a shared memory segment */
+static int cksmShmUnmap(sqlite3_file *pFile, int deleteFlag){
+ pFile = ORIGFILE(pFile);
+ return pFile->pMethods->xShmUnmap(pFile,deleteFlag);
+}
+
+/* Fetch a page of a memory-mapped file */
+static int cksmFetch(
+ sqlite3_file *pFile,
+ sqlite3_int64 iOfst,
+ int iAmt,
+ void **pp
+){
+ CksmFile *p = (CksmFile *)pFile;
+ if( p->computeCksm ){
+ *pp = 0;
+ return SQLITE_OK;
+ }
+ pFile = ORIGFILE(pFile);
+ return pFile->pMethods->xFetch(pFile, iOfst, iAmt, pp);
+}
+
+/* Release a memory-mapped page */
+static int cksmUnfetch(sqlite3_file *pFile, sqlite3_int64 iOfst, void *pPage){
+ pFile = ORIGFILE(pFile);
+ return pFile->pMethods->xUnfetch(pFile, iOfst, pPage);
+}
+
+/*
+** Open a cksm file handle.
+*/
+static int cksmOpen(
+ sqlite3_vfs *pVfs,
+ const char *zName,
+ sqlite3_file *pFile,
+ int flags,
+ int *pOutFlags
+){
+ CksmFile *p;
+ sqlite3_file *pSubFile;
+ sqlite3_vfs *pSubVfs;
+ int rc;
+ pSubVfs = ORIGVFS(pVfs);
+ if( (flags & (SQLITE_OPEN_MAIN_DB|SQLITE_OPEN_WAL))==0 ){
+ return pSubVfs->xOpen(pSubVfs, zName, pFile, flags, pOutFlags);
+ }
+ p = (CksmFile*)pFile;
+ memset(p, 0, sizeof(*p));
+ pSubFile = ORIGFILE(pFile);
+ p->base.pMethods = &cksm_io_methods;
+ rc = pSubVfs->xOpen(pSubVfs, zName, pSubFile, flags, pOutFlags);
+ if( rc ) goto cksm_open_done;
+ if( flags & SQLITE_OPEN_WAL ){
+ sqlite3_file *pDb = sqlite3_database_file_object(zName);
+ p->pPartner = (CksmFile*)pDb;
+ assert( p->pPartner->pPartner==0 );
+ p->pPartner->pPartner = p;
+ p->isWal = 1;
+ p->computeCksm = p->pPartner->computeCksm;
+ }else{
+ p->isWal = 0;
+ p->computeCksm = 0;
+ }
+cksm_open_done:
+ if( rc ) pFile->pMethods = 0;
+ return rc;
+}
+
+/*
+** All other VFS methods are pass-thrus.
+*/
+static int cksmDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
+ return ORIGVFS(pVfs)->xDelete(ORIGVFS(pVfs), zPath, dirSync);
+}
+static int cksmAccess(
+ sqlite3_vfs *pVfs,
+ const char *zPath,
+ int flags,
+ int *pResOut
+){
+ return ORIGVFS(pVfs)->xAccess(ORIGVFS(pVfs), zPath, flags, pResOut);
+}
+static int cksmFullPathname(
+ sqlite3_vfs *pVfs,
+ const char *zPath,
+ int nOut,
+ char *zOut
+){
+ return ORIGVFS(pVfs)->xFullPathname(ORIGVFS(pVfs),zPath,nOut,zOut);
+}
+static void *cksmDlOpen(sqlite3_vfs *pVfs, const char *zPath){
+ return ORIGVFS(pVfs)->xDlOpen(ORIGVFS(pVfs), zPath);
+}
+static void cksmDlError(sqlite3_vfs *pVfs, int nByte, char *zErrMsg){
+ ORIGVFS(pVfs)->xDlError(ORIGVFS(pVfs), nByte, zErrMsg);
+}
+static void (*cksmDlSym(sqlite3_vfs *pVfs, void *p, const char *zSym))(void){
+ return ORIGVFS(pVfs)->xDlSym(ORIGVFS(pVfs), p, zSym);
+}
+static void cksmDlClose(sqlite3_vfs *pVfs, void *pHandle){
+ ORIGVFS(pVfs)->xDlClose(ORIGVFS(pVfs), pHandle);
+}
+static int cksmRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
+ return ORIGVFS(pVfs)->xRandomness(ORIGVFS(pVfs), nByte, zBufOut);
+}
+static int cksmSleep(sqlite3_vfs *pVfs, int nMicro){
+ return ORIGVFS(pVfs)->xSleep(ORIGVFS(pVfs), nMicro);
+}
+static int cksmCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
+ return ORIGVFS(pVfs)->xCurrentTime(ORIGVFS(pVfs), pTimeOut);
+}
+static int cksmGetLastError(sqlite3_vfs *pVfs, int a, char *b){
+ return ORIGVFS(pVfs)->xGetLastError(ORIGVFS(pVfs), a, b);
+}
+static int cksmCurrentTimeInt64(sqlite3_vfs *pVfs, sqlite3_int64 *p){
+ return ORIGVFS(pVfs)->xCurrentTimeInt64(ORIGVFS(pVfs), p);
+}
+static int cksmSetSystemCall(
+ sqlite3_vfs *pVfs,
+ const char *zName,
+ sqlite3_syscall_ptr pCall
+){
+ return ORIGVFS(pVfs)->xSetSystemCall(ORIGVFS(pVfs),zName,pCall);
+}
+static sqlite3_syscall_ptr cksmGetSystemCall(
+ sqlite3_vfs *pVfs,
+ const char *zName
+){
+ return ORIGVFS(pVfs)->xGetSystemCall(ORIGVFS(pVfs),zName);
+}
+static const char *cksmNextSystemCall(sqlite3_vfs *pVfs, const char *zName){
+ return ORIGVFS(pVfs)->xNextSystemCall(ORIGVFS(pVfs), zName);
+}
+
+/* Register the verify_checksum() SQL function.
+*/
+static int cksmRegisterFunc(
+ sqlite3 *db,
+ char **pzErrMsg,
+ const sqlite3_api_routines *pApi
+){
+ int rc;
+ if( db==0 ) return SQLITE_OK;
+ rc = sqlite3_create_function(db, "verify_checksum", 1,
+ SQLITE_UTF8|SQLITE_INNOCUOUS|SQLITE_DETERMINISTIC,
+ 0, cksmVerifyFunc, 0, 0);
+ return rc;
+}
+
+/*
+** Register the cksum VFS as the default VFS for the system.
+** Also make arrangements to automatically register the "verify_checksum()"
+** SQL function on each new database connection.
+*/
+static int cksmRegisterVfs(void){
+ int rc = SQLITE_OK;
+ sqlite3_vfs *pOrig;
+ if( sqlite3_vfs_find("cksum")!=0 ) return SQLITE_OK;
+ pOrig = sqlite3_vfs_find(0);
+ cksm_vfs.iVersion = pOrig->iVersion;
+ cksm_vfs.pAppData = pOrig;
+ cksm_vfs.szOsFile = pOrig->szOsFile + sizeof(CksmFile);
+ rc = sqlite3_vfs_register(&cksm_vfs, 1);
+ if( rc==SQLITE_OK ){
+ rc = sqlite3_auto_extension((void(*)(void))cksmRegisterFunc);
+ }
+ return rc;
+}
+
+#if defined(SQLITE_CKSUMVFS_STATIC)
+/* This variant of the initializer runs when the extension is
+** statically linked.
+*/
+int sqlite3_register_cksumvfs(const char *NotUsed){
+ (void)NotUsed;
+ return cksmRegisterVfs();
+}
+#endif /* defined(SQLITE_CKSUMVFS_STATIC */
+
+#if !defined(SQLITE_CKSUMVFS_STATIC)
+/* This variant of the initializer function is used when the
+** extension is shared library to be loaded at run-time.
+*/
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+/*
+** This routine is called by sqlite3_load_extension() when the
+** extension is first loaded.
+***/
+int sqlite3_cksumvfs_init(
+ sqlite3 *db,
+ char **pzErrMsg,
+ const sqlite3_api_routines *pApi
+){
+ int rc;
+ SQLITE_EXTENSION_INIT2(pApi);
+ (void)pzErrMsg; /* not used */
+ rc = cksmRegisterFunc(db, 0, 0);
+ if( rc==SQLITE_OK ){
+
+ }
+ if( rc==SQLITE_OK ){
+ rc = cksmRegisterVfs();
+ }
+ if( rc==SQLITE_OK ) rc = SQLITE_OK_LOAD_PERMANENTLY;
+ return rc;
+}
+#endif /* !defined(SQLITE_CKSUMVFS_STATIC) */
projects / thirdparty / sqlite.git / commitdiff
