diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/os_unix.c | 2 | ||||
| -rw-r--r-- | src/os_win.c | 2 | ||||
| -rw-r--r-- | src/wal.c | 24 |
3 files changed, 22 insertions, 6 deletions
diff --git a/src/os_unix.c b/src/os_unix.c index 6cb594478..48f4d3884 100644 --- a/src/os_unix.c +++ b/src/os_unix.c @@ -3186,7 +3186,7 @@ struct unixShm { /* ** Constants used for locking */ -#define UNIX_SHM_BASE 32 /* Byte offset of the first lock byte */ +#define UNIX_SHM_BASE 80 /* Byte offset of the first lock byte */ #define UNIX_SHM_DMS 0x01 /* Mask for Dead-Man-Switch lock */ #define UNIX_SHM_A 0x10 /* Mask for region locks... */ #define UNIX_SHM_B 0x20 diff --git a/src/os_win.c b/src/os_win.c index 6e908c38e..7f1b5ebb1 100644 --- a/src/os_win.c +++ b/src/os_win.c @@ -1271,7 +1271,7 @@ struct winShm { /* ** Constants used for locking */ -#define WIN_SHM_BASE 32 /* Byte offset of the first lock byte */ +#define WIN_SHM_BASE 80 /* Byte offset of the first lock byte */ #define WIN_SHM_DMS 0x01 /* Mask for Dead-Man-Switch lock */ #define WIN_SHM_A 0x10 /* Mask for region locks... */ #define WIN_SHM_B 0x20 @@ -34,7 +34,7 @@ ** The WAL header is 24 bytes in size and consists of the following six ** big-endian 32-bit unsigned integer values: ** -** 0: Magic number. 0x377f0682 (big endian) +** 0: Magic number. 0x377f0682 or 0x377f0683 ** 4: File format version. Currently 3007000 ** 8: Database page size. Example: 1024 ** 12: Checkpoint sequence number @@ -61,9 +61,13 @@ ** salt values in the wal-header ** ** (2) The checksum values in the final 8 bytes of the frame-header -** exactly match the checksum computed consecutively on -** (a) the first 16 bytes of the frame-header, and -** (b) the frame data. +** exactly match the checksum computed consecutively on the +** WAL header and the first 8 bytes and the content of all frames +** up to and including the current frame. +** +** The checksum is computed using 32-bit big-endian integers if the +** magic number in the first 4 bytes of the WAL is 0x377f0683 and it +** is computed using little-endian if the magic number is 0x377f0682. ** ** On a checkpoint, the WAL is first VFS.xSync-ed, then valid content of the ** WAL is transferred into the database, then the database is VFS.xSync-ed. @@ -947,6 +951,18 @@ int sqlite3WalOpen( assert( zDbName && zDbName[0] ); assert( pDbFd ); + /* In the amalgamation, the os_unix.c and os_win.c source files come before + ** this source file. Verify that the #defines of the locking byte offsets + ** in os_unix.c and os_win.c agree with the WALINDEX_LOCK_OFFSET value. + */ +#ifdef WIN_SHM_BASE + assert( WIN_SHM_BASE==WALINDEX_LOCK_OFFSET ); +#endif +#ifdef UNIX_SHM_BASE + assert( UNIX_SHM_BASE==WALINDEX_LOCK_OFFSET ); +#endif + + /* Allocate an instance of struct Wal to return. */ *ppWal = 0; nWal = sqlite3Strlen30(zDbName) + 5; |