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/*
** A utility for printing content from the wal-index or "shm" file.
*/
#include <stdio.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <assert.h>
#define ISDIGIT(X) isdigit((unsigned char)(X))
#define ISPRINT(X) isprint((unsigned char)(X))
#if !defined(_MSC_VER)
#include <unistd.h>
#include <sys/types.h>
#else
#include <io.h>
#endif
#include <stdlib.h>
#include <string.h>
static int fd = -1; /* The open SHM file */
/* Report an out-of-memory error and die.
*/
static void out_of_memory(void){
fprintf(stderr,"Out of memory...\n");
exit(1);
}
/*
** Read content from the file.
**
** Space to hold the content is obtained from malloc() and needs to be
** freed by the caller.
*/
static unsigned char *getContent(int ofst, int nByte){
unsigned char *aData;
aData = malloc(nByte);
if( aData==0 ) out_of_memory();
lseek(fd, ofst, SEEK_SET);
read(fd, aData, nByte);
return aData;
}
/*
** Flags values
*/
#define FG_HEX 1 /* Show as hex */
#define FG_NBO 2 /* Native byte order */
#define FG_PGSZ 4 /* Show as page-size */
/* Print a line of decode output showing a 4-byte integer.
*/
static void print_decode_line(
unsigned char *aData, /* Content being decoded */
int ofst, int nByte, /* Start and size of decode */
unsigned flg, /* Display flags */
const char *zMsg /* Message to append */
){
int i, j;
int val = aData[ofst];
char zBuf[100];
sprintf(zBuf, " %03x: %02x", ofst, aData[ofst]);
i = (int)strlen(zBuf);
for(j=1; j<4; j++){
if( j>=nByte ){
sprintf(&zBuf[i], " ");
}else{
sprintf(&zBuf[i], " %02x", aData[ofst+j]);
val = val*256 + aData[ofst+j];
}
i += (int)strlen(&zBuf[i]);
}
if( nByte==8 ){
for(j=4; j<8; j++){
sprintf(&zBuf[i], " %02x", aData[ofst+j]);
i += (int)strlen(&zBuf[i]);
}
}
if( flg & FG_NBO ){
assert( nByte==4 );
memcpy(&val, aData+ofst, 4);
}
sprintf(&zBuf[i], " ");
i += 12;
if( flg & FG_PGSZ ){
unsigned short sz;
memcpy(&sz, aData+ofst, 2);
sprintf(&zBuf[i], " %9d", sz==1 ? 65536 : sz);
}else if( flg & FG_HEX ){
sprintf(&zBuf[i], " 0x%08x", val);
}else if( nByte<8 ){
sprintf(&zBuf[i], " %9d", val);
}
printf("%s %s\n", zBuf, zMsg);
}
/*
** Print an instance of the WalIndexHdr object. ix is either 0 or 1
** to select which header to print.
*/
static void print_index_hdr(unsigned char *aData, int ix){
int i;
assert( ix==0 || ix==1 );
i = ix ? 48 : 0;
print_decode_line(aData, 0+i, 4, FG_NBO, "Wal-index version");
print_decode_line(aData, 4+i, 4, 0, "unused padding");
print_decode_line(aData, 8+i, 4, FG_NBO, "transaction counter");
print_decode_line(aData,12+i, 1, 0, "1 when initialized");
print_decode_line(aData,13+i, 1, 0, "true if WAL cksums are bigendian");
print_decode_line(aData,14+i, 2, FG_PGSZ, "database page size");
print_decode_line(aData,16+i, 4, FG_NBO, "mxFrame");
print_decode_line(aData,20+i, 4, FG_NBO, "Size of database in pages");
print_decode_line(aData,24+i, 8, 0, "Cksum of last frame in -wal");
print_decode_line(aData,32+i, 8, 0, "Salt values from the -wal");
print_decode_line(aData,40+i, 8, 0, "Cksum over all prior fields");
}
/*
** Print the WalCkptInfo object
*/
static void print_ckpt_info(unsigned char *aData){
const int i = 96;
int j;
print_decode_line(aData, 0+i, 4, FG_NBO, "nBackfill");
for(j=0; j<5; j++){
char zLabel[100];
sprintf(zLabel, "aReadMark[%d]", j);
print_decode_line(aData, 4*j+4+i, 4, FG_NBO, zLabel);
}
print_decode_line(aData,24+i, 8, 0, "aLock");
print_decode_line(aData,32+i, 4, FG_NBO, "nBackfillAttempted");
print_decode_line(aData,36+i, 4, FG_NBO, "notUsed0");
}
int main(int argc, char **argv){
unsigned char *aData;
if( argc<2 ){
fprintf(stderr,"Usage: %s FILENAME\n", argv[0]);
exit(1);
}
fd = open(argv[1], O_RDONLY);
if( fd<0 ){
fprintf(stderr,"%s: can't open %s\n", argv[0], argv[1]);
exit(1);
}
aData = getContent(0, 136);
print_index_hdr(aData, 0);
print_index_hdr(aData, 1);
print_ckpt_info(aData);
free(aData);
close(fd);
return 0;
}
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