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/*
** A utility for printing an SQLite database journal.
*/
#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
/*
** state information
*/
static int pageSize = 1024;
static int sectorSize = 512;
static FILE *db = 0;
static int fileSize = 0;
static unsigned cksumNonce = 0;
/* Report a memory allocation error */
static void out_of_memory(void){
fprintf(stderr,"Out of memory...\n");
exit(1);
}
/*
** Read N bytes of memory starting at iOfst into space obtained
** from malloc().
*/
static unsigned char *read_content(int N, int iOfst){
int got;
unsigned char *pBuf = malloc(N);
if( pBuf==0 ) out_of_memory();
fseek(db, iOfst, SEEK_SET);
got = fread(pBuf, 1, N, db);
if( got<0 ){
fprintf(stderr, "I/O error reading %d bytes from %d\n", N, iOfst);
memset(pBuf, 0, N);
}else if( got<N ){
fprintf(stderr, "Short read: got only %d of %d bytes from %d\n",
got, N, iOfst);
memset(&pBuf[got], 0, N-got);
}
return pBuf;
}
/* Print a line of decode output showing a 4-byte integer.
*/
static unsigned print_decode_line(
const unsigned char *aData, /* Content being decoded */
int ofst, int nByte, /* Start and size of decode */
const char *zMsg /* Message to append */
){
int i, j;
unsigned val = aData[ofst];
char zBuf[100];
sprintf(zBuf, " %05x: %02x", ofst, aData[ofst]);
i = 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 += strlen(&zBuf[i]);
}
sprintf(&zBuf[i], " %10u", val);
printf("%s %s\n", zBuf, zMsg);
return val;
}
/*
** Read and print a journal header. Store key information (page size, etc)
** in global variables.
*/
static unsigned decode_journal_header(int iOfst){
unsigned char *pHdr = read_content(64, iOfst);
unsigned nPage;
printf("Header at offset %d:\n", iOfst);
print_decode_line(pHdr, 0, 4, "Header part 1 (3654616569)");
print_decode_line(pHdr, 4, 4, "Header part 2 (547447767)");
nPage =
print_decode_line(pHdr, 8, 4, "page count");
cksumNonce =
print_decode_line(pHdr, 12, 4, "chksum nonce");
print_decode_line(pHdr, 16, 4, "initial database size in pages");
sectorSize =
print_decode_line(pHdr, 20, 4, "sector size");
pageSize =
print_decode_line(pHdr, 24, 4, "page size");
print_decode_line(pHdr, 28, 4, "zero");
print_decode_line(pHdr, 32, 4, "zero");
print_decode_line(pHdr, 36, 4, "zero");
print_decode_line(pHdr, 40, 4, "zero");
free(pHdr);
return nPage;
}
static void print_page(int iOfst){
unsigned char *aData;
char zTitle[50];
aData = read_content(pageSize+8, iOfst);
sprintf(zTitle, "page number for page at offset %d", iOfst);
print_decode_line(aData-iOfst, iOfst, 4, zTitle);
free(aData);
}
int main(int argc, char **argv){
int nPage, cnt;
int iOfst;
if( argc!=2 ){
fprintf(stderr,"Usage: %s FILENAME\n", argv[0]);
exit(1);
}
db = fopen(argv[1], "rb");
if( db==0 ){
fprintf(stderr,"%s: can't open %s\n", argv[0], argv[1]);
exit(1);
}
fseek(db, 0, SEEK_END);
fileSize = ftell(db);
printf("journal file size: %d bytes\n", fileSize);
fseek(db, 0, SEEK_SET);
iOfst = 0;
while( iOfst<fileSize ){
cnt = nPage = (int)decode_journal_header(iOfst);
if( cnt==0 ){
cnt = (fileSize - sectorSize)/(pageSize+8);
}
iOfst += sectorSize;
while( cnt && iOfst<fileSize ){
print_page(iOfst);
iOfst += pageSize+8;
}
iOfst = (iOfst/sectorSize + 1)*sectorSize;
}
fclose(db);
return 0;
}
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