858 lines
26 KiB
C
858 lines
26 KiB
C
/*
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** 2008 Jan 22
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**
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** The author disclaims copyright to this source code. In place of
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** a legal notice, here is a blessing:
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**
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** May you do good and not evil.
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** May you find forgiveness for yourself and forgive others.
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** May you share freely, never taking more than you give.
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**
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******************************************************************************
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**
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** This file contains code for a VFS layer that acts as a wrapper around
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** an existing VFS. The code in this file attempts to verify that SQLite
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** correctly populates and syncs a journal file before writing to a
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** corresponding database file.
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**
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** INTERFACE
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**
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** The public interface to this wrapper VFS is two functions:
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**
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** jt_register()
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** jt_unregister()
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**
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** See header comments associated with those two functions below for
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** details.
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**
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** LIMITATIONS
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**
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** This wrapper will not work if "PRAGMA synchronous = off" is used.
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**
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** OPERATION
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**
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** Starting a Transaction:
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**
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** When a write-transaction is started, the contents of the database is
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** inspected and the following data stored as part of the database file
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** handle (type struct jt_file):
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**
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** a) The page-size of the database file.
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** b) The number of pages that are in the database file.
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** c) The set of page numbers corresponding to free-list leaf pages.
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** d) A check-sum for every page in the database file.
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**
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** The start of a write-transaction is deemed to have occurred when a
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** 28-byte journal header is written to byte offset 0 of the journal
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** file.
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**
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** Syncing the Journal File:
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**
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** Whenever the xSync method is invoked to sync a journal-file, the
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** contents of the journal file are read. For each page written to
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** the journal file, a check-sum is calculated and compared to the
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** check-sum calculated for the corresponding database page when the
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** write-transaction was initialized. The success of the comparison
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** is assert()ed. So if SQLite has written something other than the
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** original content to the database file, an assert() will fail.
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**
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** Additionally, the set of page numbers for which records exist in
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** the journal file is added to (unioned with) the set of page numbers
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** corresponding to free-list leaf pages collected when the
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** write-transaction was initialized. This set comprises the page-numbers
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** corresponding to those pages that SQLite may now safely modify.
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**
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** Writing to the Database File:
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**
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** When a block of data is written to a database file, the following
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** invariants are asserted:
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**
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** a) That the block of data is an aligned block of page-size bytes.
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**
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** b) That if the page being written did not exist when the
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** transaction was started (i.e. the database file is growing), then
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** the journal-file must have been synced at least once since
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** the start of the transaction.
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**
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** c) That if the page being written did exist when the transaction
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** was started, then the page must have either been a free-list
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** leaf page at the start of the transaction, or else must have
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** been stored in the journal file prior to the most recent sync.
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**
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** Closing a Transaction:
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**
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** When a transaction is closed, all data collected at the start of
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** the transaction, or following an xSync of a journal-file, is
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** discarded. The end of a transaction is recognized when any one
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** of the following occur:
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**
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** a) A block of zeroes (or anything else that is not a valid
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** journal-header) is written to the start of the journal file.
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**
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** b) A journal file is truncated to zero bytes in size using xTruncate.
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**
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** c) The journal file is deleted using xDelete.
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*/
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#if SQLITE_TEST /* This file is used for testing only */
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#include "sqlite3.h"
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#include "sqliteInt.h"
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/*
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** Maximum pathname length supported by the jt backend.
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*/
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#define JT_MAX_PATHNAME 512
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/*
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** Name used to identify this VFS.
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*/
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#define JT_VFS_NAME "jt"
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typedef struct jt_file jt_file;
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struct jt_file {
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sqlite3_file base;
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const char *zName; /* Name of open file */
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int flags; /* Flags the file was opened with */
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/* The following are only used by database file file handles */
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int eLock; /* Current lock held on the file */
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u32 nPage; /* Size of file in pages when transaction started */
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u32 nPagesize; /* Page size when transaction started */
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Bitvec *pWritable; /* Bitvec of pages that may be written to the file */
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u32 *aCksum; /* Checksum for first nPage pages */
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int nSync; /* Number of times journal file has been synced */
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/* Only used by journal file-handles */
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sqlite3_int64 iMaxOff; /* Maximum offset written to this transaction */
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jt_file *pNext; /* All files are stored in a linked list */
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sqlite3_file *pReal; /* The file handle for the underlying vfs */
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};
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/*
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** Method declarations for jt_file.
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*/
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static int jtClose(sqlite3_file*);
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static int jtRead(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
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static int jtWrite(sqlite3_file*,const void*,int iAmt, sqlite3_int64 iOfst);
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static int jtTruncate(sqlite3_file*, sqlite3_int64 size);
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static int jtSync(sqlite3_file*, int flags);
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static int jtFileSize(sqlite3_file*, sqlite3_int64 *pSize);
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static int jtLock(sqlite3_file*, int);
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static int jtUnlock(sqlite3_file*, int);
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static int jtCheckReservedLock(sqlite3_file*, int *);
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static int jtFileControl(sqlite3_file*, int op, void *pArg);
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static int jtSectorSize(sqlite3_file*);
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static int jtDeviceCharacteristics(sqlite3_file*);
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/*
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** Method declarations for jt_vfs.
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*/
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static int jtOpen(sqlite3_vfs*, const char *, sqlite3_file*, int , int *);
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static int jtDelete(sqlite3_vfs*, const char *zName, int syncDir);
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static int jtAccess(sqlite3_vfs*, const char *zName, int flags, int *);
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static int jtFullPathname(sqlite3_vfs*, const char *zName, int, char *zOut);
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static void *jtDlOpen(sqlite3_vfs*, const char *zFilename);
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static void jtDlError(sqlite3_vfs*, int nByte, char *zErrMsg);
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static void (*jtDlSym(sqlite3_vfs*,void*, const char *zSymbol))(void);
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static void jtDlClose(sqlite3_vfs*, void*);
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static int jtRandomness(sqlite3_vfs*, int nByte, char *zOut);
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static int jtSleep(sqlite3_vfs*, int microseconds);
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static int jtCurrentTime(sqlite3_vfs*, double*);
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static int jtCurrentTimeInt64(sqlite3_vfs*, sqlite3_int64*);
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static sqlite3_vfs jt_vfs = {
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2, /* iVersion */
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sizeof(jt_file), /* szOsFile */
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JT_MAX_PATHNAME, /* mxPathname */
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0, /* pNext */
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JT_VFS_NAME, /* zName */
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0, /* pAppData */
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jtOpen, /* xOpen */
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jtDelete, /* xDelete */
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jtAccess, /* xAccess */
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jtFullPathname, /* xFullPathname */
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jtDlOpen, /* xDlOpen */
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jtDlError, /* xDlError */
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jtDlSym, /* xDlSym */
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jtDlClose, /* xDlClose */
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jtRandomness, /* xRandomness */
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jtSleep, /* xSleep */
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jtCurrentTime, /* xCurrentTime */
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0, /* xGetLastError */
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jtCurrentTimeInt64 /* xCurrentTimeInt64 */
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};
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static sqlite3_io_methods jt_io_methods = {
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1, /* iVersion */
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jtClose, /* xClose */
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jtRead, /* xRead */
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jtWrite, /* xWrite */
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jtTruncate, /* xTruncate */
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jtSync, /* xSync */
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jtFileSize, /* xFileSize */
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jtLock, /* xLock */
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jtUnlock, /* xUnlock */
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jtCheckReservedLock, /* xCheckReservedLock */
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jtFileControl, /* xFileControl */
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jtSectorSize, /* xSectorSize */
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jtDeviceCharacteristics /* xDeviceCharacteristics */
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};
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struct JtGlobal {
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sqlite3_vfs *pVfs; /* Parent VFS */
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jt_file *pList; /* List of all open files */
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};
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static struct JtGlobal g = {0, 0};
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/*
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** Functions to obtain and relinquish a mutex to protect g.pList. The
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** STATIC_PRNG mutex is reused, purely for the sake of convenience.
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*/
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static void enterJtMutex(void){
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sqlite3_mutex_enter(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_PRNG));
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}
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static void leaveJtMutex(void){
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sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_PRNG));
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}
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extern int sqlite3_io_error_pending;
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extern int sqlite3_io_error_hit;
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static void stop_ioerr_simulation(int *piSave, int *piSave2){
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*piSave = sqlite3_io_error_pending;
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*piSave2 = sqlite3_io_error_hit;
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sqlite3_io_error_pending = -1;
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sqlite3_io_error_hit = 0;
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}
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static void start_ioerr_simulation(int iSave, int iSave2){
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sqlite3_io_error_pending = iSave;
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sqlite3_io_error_hit = iSave2;
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}
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/*
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** The jt_file pointed to by the argument may or may not be a file-handle
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** open on a main database file. If it is, and a transaction is currently
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** opened on the file, then discard all transaction related data.
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*/
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static void closeTransaction(jt_file *p){
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sqlite3BitvecDestroy(p->pWritable);
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sqlite3_free(p->aCksum);
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p->pWritable = 0;
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p->aCksum = 0;
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p->nSync = 0;
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}
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/*
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** Close an jt-file.
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*/
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static int jtClose(sqlite3_file *pFile){
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jt_file **pp;
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jt_file *p = (jt_file *)pFile;
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closeTransaction(p);
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enterJtMutex();
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if( p->zName ){
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for(pp=&g.pList; *pp!=p; pp=&(*pp)->pNext);
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*pp = p->pNext;
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}
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leaveJtMutex();
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return sqlite3OsClose(p->pReal);
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}
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/*
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** Read data from an jt-file.
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*/
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static int jtRead(
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sqlite3_file *pFile,
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void *zBuf,
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int iAmt,
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sqlite_int64 iOfst
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){
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jt_file *p = (jt_file *)pFile;
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return sqlite3OsRead(p->pReal, zBuf, iAmt, iOfst);
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}
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/*
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** Parameter zJournal is the name of a journal file that is currently
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** open. This function locates and returns the handle opened on the
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** corresponding database file by the pager that currently has the
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** journal file opened. This file-handle is identified by the
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** following properties:
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**
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** a) SQLITE_OPEN_MAIN_DB was specified when the file was opened.
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**
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** b) The file-name specified when the file was opened matches
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** all but the final 8 characters of the journal file name.
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**
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** c) There is currently a reserved lock on the file.
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**/
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static jt_file *locateDatabaseHandle(const char *zJournal){
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jt_file *pMain = 0;
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enterJtMutex();
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for(pMain=g.pList; pMain; pMain=pMain->pNext){
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int nName = (int)(strlen(zJournal) - strlen("-journal"));
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if( (pMain->flags&SQLITE_OPEN_MAIN_DB)
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&& ((int)strlen(pMain->zName)==nName)
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&& 0==memcmp(pMain->zName, zJournal, nName)
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&& (pMain->eLock>=SQLITE_LOCK_RESERVED)
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){
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break;
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}
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}
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leaveJtMutex();
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return pMain;
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}
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/*
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** Parameter z points to a buffer of 4 bytes in size containing a
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** unsigned 32-bit integer stored in big-endian format. Decode the
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** integer and return its value.
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*/
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static u32 decodeUint32(const unsigned char *z){
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return (z[0]<<24) + (z[1]<<16) + (z[2]<<8) + z[3];
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}
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/*
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** Calculate a checksum from the buffer of length n bytes pointed to
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** by parameter z.
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*/
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static u32 genCksum(const unsigned char *z, int n){
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int i;
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u32 cksum = 0;
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for(i=0; i<n; i++){
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cksum = cksum + z[i] + (cksum<<3);
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}
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return cksum;
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}
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/*
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** The first argument, zBuf, points to a buffer containing a 28 byte
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** serialized journal header. This function deserializes four of the
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** integer fields contained in the journal header and writes their
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** values to the output variables.
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**
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** SQLITE_OK is returned if the journal-header is successfully
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** decoded. Otherwise, SQLITE_ERROR.
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*/
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static int decodeJournalHdr(
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const unsigned char *zBuf, /* Input: 28 byte journal header */
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u32 *pnRec, /* Out: Number of journalled records */
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u32 *pnPage, /* Out: Original database page count */
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u32 *pnSector, /* Out: Sector size in bytes */
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u32 *pnPagesize /* Out: Page size in bytes */
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){
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unsigned char aMagic[] = { 0xd9, 0xd5, 0x05, 0xf9, 0x20, 0xa1, 0x63, 0xd7 };
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if( memcmp(aMagic, zBuf, 8) ) return SQLITE_ERROR;
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if( pnRec ) *pnRec = decodeUint32(&zBuf[8]);
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if( pnPage ) *pnPage = decodeUint32(&zBuf[16]);
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if( pnSector ) *pnSector = decodeUint32(&zBuf[20]);
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if( pnPagesize ) *pnPagesize = decodeUint32(&zBuf[24]);
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return SQLITE_OK;
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}
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/*
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** This function is called when a new transaction is opened, just after
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** the first journal-header is written to the journal file.
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*/
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static int openTransaction(jt_file *pMain, jt_file *pJournal){
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unsigned char *aData;
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sqlite3_file *p = pMain->pReal;
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int rc = SQLITE_OK;
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closeTransaction(pMain);
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aData = sqlite3_malloc(pMain->nPagesize);
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pMain->pWritable = sqlite3BitvecCreate(pMain->nPage);
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pMain->aCksum = sqlite3_malloc(sizeof(u32) * (pMain->nPage + 1));
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pJournal->iMaxOff = 0;
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if( !pMain->pWritable || !pMain->aCksum || !aData ){
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rc = SQLITE_IOERR_NOMEM;
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}else if( pMain->nPage>0 ){
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u32 iTrunk;
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int iSave;
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int iSave2;
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stop_ioerr_simulation(&iSave, &iSave2);
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/* Read the database free-list. Add the page-number for each free-list
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** leaf to the jt_file.pWritable bitvec.
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*/
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rc = sqlite3OsRead(p, aData, pMain->nPagesize, 0);
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if( rc==SQLITE_OK ){
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u32 nDbsize = decodeUint32(&aData[28]);
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if( nDbsize>0 && memcmp(&aData[24], &aData[92], 4)==0 ){
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u32 iPg;
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for(iPg=nDbsize+1; iPg<=pMain->nPage; iPg++){
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sqlite3BitvecSet(pMain->pWritable, iPg);
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}
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}
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}
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iTrunk = decodeUint32(&aData[32]);
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while( rc==SQLITE_OK && iTrunk>0 ){
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u32 nLeaf;
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u32 iLeaf;
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sqlite3_int64 iOff = (i64)(iTrunk-1)*pMain->nPagesize;
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rc = sqlite3OsRead(p, aData, pMain->nPagesize, iOff);
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nLeaf = decodeUint32(&aData[4]);
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for(iLeaf=0; rc==SQLITE_OK && iLeaf<nLeaf; iLeaf++){
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u32 pgno = decodeUint32(&aData[8+4*iLeaf]);
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sqlite3BitvecSet(pMain->pWritable, pgno);
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}
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iTrunk = decodeUint32(aData);
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}
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/* Calculate and store a checksum for each page in the database file. */
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if( rc==SQLITE_OK ){
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int ii;
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for(ii=0; rc==SQLITE_OK && ii<(int)pMain->nPage; ii++){
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i64 iOff = (i64)(pMain->nPagesize) * (i64)ii;
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if( iOff==PENDING_BYTE ) continue;
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rc = sqlite3OsRead(pMain->pReal, aData, pMain->nPagesize, iOff);
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pMain->aCksum[ii] = genCksum(aData, pMain->nPagesize);
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if( ii+1==pMain->nPage && rc==SQLITE_IOERR_SHORT_READ ) rc = SQLITE_OK;
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}
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}
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start_ioerr_simulation(iSave, iSave2);
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}
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sqlite3_free(aData);
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return rc;
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}
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/*
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** The first argument to this function is a handle open on a journal file.
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** This function reads the journal file and adds the page number for each
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** page in the journal to the Bitvec object passed as the second argument.
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*/
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static int readJournalFile(jt_file *p, jt_file *pMain){
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int rc = SQLITE_OK;
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unsigned char zBuf[28];
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sqlite3_file *pReal = p->pReal;
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sqlite3_int64 iOff = 0;
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sqlite3_int64 iSize = p->iMaxOff;
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unsigned char *aPage;
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int iSave;
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int iSave2;
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aPage = sqlite3_malloc(pMain->nPagesize);
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if( !aPage ){
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return SQLITE_IOERR_NOMEM;
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}
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stop_ioerr_simulation(&iSave, &iSave2);
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while( rc==SQLITE_OK && iOff<iSize ){
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u32 nRec, nPage, nSector, nPagesize;
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u32 ii;
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/* Read and decode the next journal-header from the journal file. */
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rc = sqlite3OsRead(pReal, zBuf, 28, iOff);
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if( rc!=SQLITE_OK
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|| decodeJournalHdr(zBuf, &nRec, &nPage, &nSector, &nPagesize)
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){
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goto finish_rjf;
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}
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iOff += nSector;
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if( nRec==0 ){
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/* A trick. There might be another journal-header immediately
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** following this one. In this case, 0 records means 0 records,
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** not "read until the end of the file". See also ticket #2565.
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*/
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if( iSize>=(iOff+nSector) ){
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rc = sqlite3OsRead(pReal, zBuf, 28, iOff);
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if( rc!=SQLITE_OK || 0==decodeJournalHdr(zBuf, 0, 0, 0, 0) ){
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continue;
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}
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}
|
|
nRec = (u32)((iSize-iOff) / (pMain->nPagesize+8));
|
|
}
|
|
|
|
/* Read all the records that follow the journal-header just read. */
|
|
for(ii=0; rc==SQLITE_OK && ii<nRec && iOff<iSize; ii++){
|
|
u32 pgno;
|
|
rc = sqlite3OsRead(pReal, zBuf, 4, iOff);
|
|
if( rc==SQLITE_OK ){
|
|
pgno = decodeUint32(zBuf);
|
|
if( pgno>0 && pgno<=pMain->nPage ){
|
|
if( 0==sqlite3BitvecTest(pMain->pWritable, pgno) ){
|
|
rc = sqlite3OsRead(pReal, aPage, pMain->nPagesize, iOff+4);
|
|
if( rc==SQLITE_OK ){
|
|
u32 cksum = genCksum(aPage, pMain->nPagesize);
|
|
assert( cksum==pMain->aCksum[pgno-1] );
|
|
}
|
|
}
|
|
sqlite3BitvecSet(pMain->pWritable, pgno);
|
|
}
|
|
iOff += (8 + pMain->nPagesize);
|
|
}
|
|
}
|
|
|
|
iOff = ((iOff + (nSector-1)) / nSector) * nSector;
|
|
}
|
|
|
|
finish_rjf:
|
|
start_ioerr_simulation(iSave, iSave2);
|
|
sqlite3_free(aPage);
|
|
if( rc==SQLITE_IOERR_SHORT_READ ){
|
|
rc = SQLITE_OK;
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Write data to an jt-file.
|
|
*/
|
|
static int jtWrite(
|
|
sqlite3_file *pFile,
|
|
const void *zBuf,
|
|
int iAmt,
|
|
sqlite_int64 iOfst
|
|
){
|
|
int rc;
|
|
jt_file *p = (jt_file *)pFile;
|
|
if( p->flags&SQLITE_OPEN_MAIN_JOURNAL ){
|
|
if( iOfst==0 ){
|
|
jt_file *pMain = locateDatabaseHandle(p->zName);
|
|
assert( pMain );
|
|
|
|
if( iAmt==28 ){
|
|
/* Zeroing the first journal-file header. This is the end of a
|
|
** transaction. */
|
|
closeTransaction(pMain);
|
|
}else if( iAmt!=12 ){
|
|
/* Writing the first journal header to a journal file. This happens
|
|
** when a transaction is first started. */
|
|
u8 *z = (u8 *)zBuf;
|
|
pMain->nPage = decodeUint32(&z[16]);
|
|
pMain->nPagesize = decodeUint32(&z[24]);
|
|
if( SQLITE_OK!=(rc=openTransaction(pMain, p)) ){
|
|
return rc;
|
|
}
|
|
}
|
|
}
|
|
if( p->iMaxOff<(iOfst + iAmt) ){
|
|
p->iMaxOff = iOfst + iAmt;
|
|
}
|
|
}
|
|
|
|
if( p->flags&SQLITE_OPEN_MAIN_DB && p->pWritable ){
|
|
if( iAmt<(int)p->nPagesize
|
|
&& p->nPagesize%iAmt==0
|
|
&& iOfst>=(PENDING_BYTE+512)
|
|
&& iOfst+iAmt<=PENDING_BYTE+p->nPagesize
|
|
){
|
|
/* No-op. This special case is hit when the backup code is copying a
|
|
** to a database with a larger page-size than the source database and
|
|
** it needs to fill in the non-locking-region part of the original
|
|
** pending-byte page.
|
|
*/
|
|
}else{
|
|
u32 pgno = (u32)(iOfst/p->nPagesize + 1);
|
|
assert( (iAmt==1||iAmt==p->nPagesize) && ((iOfst+iAmt)%p->nPagesize)==0 );
|
|
assert( pgno<=p->nPage || p->nSync>0 );
|
|
assert( pgno>p->nPage || sqlite3BitvecTest(p->pWritable, pgno) );
|
|
}
|
|
}
|
|
|
|
rc = sqlite3OsWrite(p->pReal, zBuf, iAmt, iOfst);
|
|
if( (p->flags&SQLITE_OPEN_MAIN_JOURNAL) && iAmt==12 ){
|
|
jt_file *pMain = locateDatabaseHandle(p->zName);
|
|
int rc2 = readJournalFile(p, pMain);
|
|
if( rc==SQLITE_OK ) rc = rc2;
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Truncate an jt-file.
|
|
*/
|
|
static int jtTruncate(sqlite3_file *pFile, sqlite_int64 size){
|
|
jt_file *p = (jt_file *)pFile;
|
|
if( p->flags&SQLITE_OPEN_MAIN_JOURNAL && size==0 ){
|
|
/* Truncating a journal file. This is the end of a transaction. */
|
|
jt_file *pMain = locateDatabaseHandle(p->zName);
|
|
closeTransaction(pMain);
|
|
}
|
|
if( p->flags&SQLITE_OPEN_MAIN_DB && p->pWritable ){
|
|
u32 pgno;
|
|
u32 locking_page = (u32)(PENDING_BYTE/p->nPagesize+1);
|
|
for(pgno=(u32)(size/p->nPagesize+1); pgno<=p->nPage; pgno++){
|
|
assert( pgno==locking_page || sqlite3BitvecTest(p->pWritable, pgno) );
|
|
}
|
|
}
|
|
return sqlite3OsTruncate(p->pReal, size);
|
|
}
|
|
|
|
/*
|
|
** Sync an jt-file.
|
|
*/
|
|
static int jtSync(sqlite3_file *pFile, int flags){
|
|
jt_file *p = (jt_file *)pFile;
|
|
|
|
if( p->flags&SQLITE_OPEN_MAIN_JOURNAL ){
|
|
int rc;
|
|
jt_file *pMain; /* The associated database file */
|
|
|
|
/* The journal file is being synced. At this point, we inspect the
|
|
** contents of the file up to this point and set each bit in the
|
|
** jt_file.pWritable bitvec of the main database file associated with
|
|
** this journal file.
|
|
*/
|
|
pMain = locateDatabaseHandle(p->zName);
|
|
assert(pMain);
|
|
|
|
/* Set the bitvec values */
|
|
if( pMain->pWritable ){
|
|
pMain->nSync++;
|
|
rc = readJournalFile(p, pMain);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
}
|
|
}
|
|
|
|
return sqlite3OsSync(p->pReal, flags);
|
|
}
|
|
|
|
/*
|
|
** Return the current file-size of an jt-file.
|
|
*/
|
|
static int jtFileSize(sqlite3_file *pFile, sqlite_int64 *pSize){
|
|
jt_file *p = (jt_file *)pFile;
|
|
return sqlite3OsFileSize(p->pReal, pSize);
|
|
}
|
|
|
|
/*
|
|
** Lock an jt-file.
|
|
*/
|
|
static int jtLock(sqlite3_file *pFile, int eLock){
|
|
int rc;
|
|
jt_file *p = (jt_file *)pFile;
|
|
rc = sqlite3OsLock(p->pReal, eLock);
|
|
if( rc==SQLITE_OK && eLock>p->eLock ){
|
|
p->eLock = eLock;
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Unlock an jt-file.
|
|
*/
|
|
static int jtUnlock(sqlite3_file *pFile, int eLock){
|
|
int rc;
|
|
jt_file *p = (jt_file *)pFile;
|
|
rc = sqlite3OsUnlock(p->pReal, eLock);
|
|
if( rc==SQLITE_OK && eLock<p->eLock ){
|
|
p->eLock = eLock;
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Check if another file-handle holds a RESERVED lock on an jt-file.
|
|
*/
|
|
static int jtCheckReservedLock(sqlite3_file *pFile, int *pResOut){
|
|
jt_file *p = (jt_file *)pFile;
|
|
return sqlite3OsCheckReservedLock(p->pReal, pResOut);
|
|
}
|
|
|
|
/*
|
|
** File control method. For custom operations on an jt-file.
|
|
*/
|
|
static int jtFileControl(sqlite3_file *pFile, int op, void *pArg){
|
|
jt_file *p = (jt_file *)pFile;
|
|
return p->pReal->pMethods->xFileControl(p->pReal, op, pArg);
|
|
}
|
|
|
|
/*
|
|
** Return the sector-size in bytes for an jt-file.
|
|
*/
|
|
static int jtSectorSize(sqlite3_file *pFile){
|
|
jt_file *p = (jt_file *)pFile;
|
|
return sqlite3OsSectorSize(p->pReal);
|
|
}
|
|
|
|
/*
|
|
** Return the device characteristic flags supported by an jt-file.
|
|
*/
|
|
static int jtDeviceCharacteristics(sqlite3_file *pFile){
|
|
jt_file *p = (jt_file *)pFile;
|
|
return sqlite3OsDeviceCharacteristics(p->pReal);
|
|
}
|
|
|
|
/*
|
|
** Open an jt file handle.
|
|
*/
|
|
static int jtOpen(
|
|
sqlite3_vfs *pVfs,
|
|
const char *zName,
|
|
sqlite3_file *pFile,
|
|
int flags,
|
|
int *pOutFlags
|
|
){
|
|
int rc;
|
|
jt_file *p = (jt_file *)pFile;
|
|
pFile->pMethods = 0;
|
|
p->pReal = (sqlite3_file *)&p[1];
|
|
p->pReal->pMethods = 0;
|
|
rc = sqlite3OsOpen(g.pVfs, zName, p->pReal, flags, pOutFlags);
|
|
assert( rc==SQLITE_OK || p->pReal->pMethods==0 );
|
|
if( rc==SQLITE_OK ){
|
|
pFile->pMethods = &jt_io_methods;
|
|
p->eLock = 0;
|
|
p->zName = zName;
|
|
p->flags = flags;
|
|
p->pNext = 0;
|
|
p->pWritable = 0;
|
|
p->aCksum = 0;
|
|
enterJtMutex();
|
|
if( zName ){
|
|
p->pNext = g.pList;
|
|
g.pList = p;
|
|
}
|
|
leaveJtMutex();
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Delete the file located at zPath. If the dirSync argument is true,
|
|
** ensure the file-system modifications are synced to disk before
|
|
** returning.
|
|
*/
|
|
static int jtDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
|
|
int nPath = (int)strlen(zPath);
|
|
if( nPath>8 && 0==strcmp("-journal", &zPath[nPath-8]) ){
|
|
/* Deleting a journal file. The end of a transaction. */
|
|
jt_file *pMain = locateDatabaseHandle(zPath);
|
|
if( pMain ){
|
|
closeTransaction(pMain);
|
|
}
|
|
}
|
|
|
|
return sqlite3OsDelete(g.pVfs, zPath, dirSync);
|
|
}
|
|
|
|
/*
|
|
** Test for access permissions. Return true if the requested permission
|
|
** is available, or false otherwise.
|
|
*/
|
|
static int jtAccess(
|
|
sqlite3_vfs *pVfs,
|
|
const char *zPath,
|
|
int flags,
|
|
int *pResOut
|
|
){
|
|
return sqlite3OsAccess(g.pVfs, zPath, flags, pResOut);
|
|
}
|
|
|
|
/*
|
|
** Populate buffer zOut with the full canonical pathname corresponding
|
|
** to the pathname in zPath. zOut is guaranteed to point to a buffer
|
|
** of at least (JT_MAX_PATHNAME+1) bytes.
|
|
*/
|
|
static int jtFullPathname(
|
|
sqlite3_vfs *pVfs,
|
|
const char *zPath,
|
|
int nOut,
|
|
char *zOut
|
|
){
|
|
return sqlite3OsFullPathname(g.pVfs, zPath, nOut, zOut);
|
|
}
|
|
|
|
/*
|
|
** Open the dynamic library located at zPath and return a handle.
|
|
*/
|
|
static void *jtDlOpen(sqlite3_vfs *pVfs, const char *zPath){
|
|
return g.pVfs->xDlOpen(g.pVfs, zPath);
|
|
}
|
|
|
|
/*
|
|
** Populate the buffer zErrMsg (size nByte bytes) with a human readable
|
|
** utf-8 string describing the most recent error encountered associated
|
|
** with dynamic libraries.
|
|
*/
|
|
static void jtDlError(sqlite3_vfs *pVfs, int nByte, char *zErrMsg){
|
|
g.pVfs->xDlError(g.pVfs, nByte, zErrMsg);
|
|
}
|
|
|
|
/*
|
|
** Return a pointer to the symbol zSymbol in the dynamic library pHandle.
|
|
*/
|
|
static void (*jtDlSym(sqlite3_vfs *pVfs, void *p, const char *zSym))(void){
|
|
return g.pVfs->xDlSym(g.pVfs, p, zSym);
|
|
}
|
|
|
|
/*
|
|
** Close the dynamic library handle pHandle.
|
|
*/
|
|
static void jtDlClose(sqlite3_vfs *pVfs, void *pHandle){
|
|
g.pVfs->xDlClose(g.pVfs, pHandle);
|
|
}
|
|
|
|
/*
|
|
** Populate the buffer pointed to by zBufOut with nByte bytes of
|
|
** random data.
|
|
*/
|
|
static int jtRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
|
|
return sqlite3OsRandomness(g.pVfs, nByte, zBufOut);
|
|
}
|
|
|
|
/*
|
|
** Sleep for nMicro microseconds. Return the number of microseconds
|
|
** actually slept.
|
|
*/
|
|
static int jtSleep(sqlite3_vfs *pVfs, int nMicro){
|
|
return sqlite3OsSleep(g.pVfs, nMicro);
|
|
}
|
|
|
|
/*
|
|
** Return the current time as a Julian Day number in *pTimeOut.
|
|
*/
|
|
static int jtCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
|
|
return g.pVfs->xCurrentTime(g.pVfs, pTimeOut);
|
|
}
|
|
/*
|
|
** Return the current time as a Julian Day number in *pTimeOut.
|
|
*/
|
|
static int jtCurrentTimeInt64(sqlite3_vfs *pVfs, sqlite3_int64 *pTimeOut){
|
|
return g.pVfs->xCurrentTimeInt64(g.pVfs, pTimeOut);
|
|
}
|
|
|
|
/**************************************************************************
|
|
** Start of public API.
|
|
*/
|
|
|
|
/*
|
|
** Configure the jt VFS as a wrapper around the VFS named by parameter
|
|
** zWrap. If the isDefault parameter is true, then the jt VFS is installed
|
|
** as the new default VFS for SQLite connections. If isDefault is not
|
|
** true, then the jt VFS is installed as non-default. In this case it
|
|
** is available via its name, "jt".
|
|
*/
|
|
int jt_register(char *zWrap, int isDefault){
|
|
g.pVfs = sqlite3_vfs_find(zWrap);
|
|
if( g.pVfs==0 ){
|
|
return SQLITE_ERROR;
|
|
}
|
|
jt_vfs.szOsFile = sizeof(jt_file) + g.pVfs->szOsFile;
|
|
if( g.pVfs->iVersion==1 ){
|
|
jt_vfs.iVersion = 1;
|
|
}else if( g.pVfs->xCurrentTimeInt64==0 ){
|
|
jt_vfs.xCurrentTimeInt64 = 0;
|
|
}
|
|
sqlite3_vfs_register(&jt_vfs, isDefault);
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Uninstall the jt VFS, if it is installed.
|
|
*/
|
|
void jt_unregister(void){
|
|
sqlite3_vfs_unregister(&jt_vfs);
|
|
}
|
|
|
|
#endif
|