mirror of
https://github.com/sqlite/sqlite.git
synced 2024-11-25 00:49:41 +01:00
140 lines
3.5 KiB
C
140 lines
3.5 KiB
C
/*
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** A utility for printing an SQLite database journal.
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*/
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#include <stdio.h>
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#include <ctype.h>
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#include <stdlib.h>
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#include <string.h>
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/*
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** state information
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*/
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static int pageSize = 1024;
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static int sectorSize = 512;
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static FILE *db = 0;
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static int showPageContent = 0;
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static int fileSize = 0;
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static unsigned cksumNonce = 0;
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/* Report a memory allocation error */
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static void out_of_memory(void){
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fprintf(stderr,"Out of memory...\n");
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exit(1);
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}
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/*
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** Read N bytes of memory starting at iOfst into space obtained
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** from malloc().
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*/
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static char *read_content(int N, int iOfst){
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int got;
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char *pBuf = malloc(N);
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if( pBuf==0 ) out_of_memory();
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fseek(db, iOfst, SEEK_SET);
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got = fread(pBuf, 1, N, db);
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if( got<0 ){
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fprintf(stderr, "I/O error reading %d bytes from %d\n", N, iOfst);
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memset(pBuf, 0, N);
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}else if( got<N ){
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fprintf(stderr, "Short read: got only %d of %d bytes from %d\n",
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got, N, iOfst);
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memset(&pBuf[got], 0, N-got);
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}
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return pBuf;
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}
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/* Print a line of decode output showing a 4-byte integer.
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*/
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static unsigned print_decode_line(
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unsigned char *aData, /* Content being decoded */
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int ofst, int nByte, /* Start and size of decode */
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const char *zMsg /* Message to append */
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){
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int i, j;
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unsigned val = aData[ofst];
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char zBuf[100];
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sprintf(zBuf, " %03x: %02x", ofst, aData[ofst]);
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i = strlen(zBuf);
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for(j=1; j<4; j++){
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if( j>=nByte ){
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sprintf(&zBuf[i], " ");
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}else{
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sprintf(&zBuf[i], " %02x", aData[ofst+j]);
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val = val*256 + aData[ofst+j];
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}
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i += strlen(&zBuf[i]);
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}
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sprintf(&zBuf[i], " %10u", val);
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printf("%s %s\n", zBuf, zMsg);
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return val;
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}
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/*
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** Read and print a journal header. Store key information (page size, etc)
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** in global variables.
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*/
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static unsigned decode_journal_header(int iOfst){
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char *pHdr = read_content(64, iOfst);
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unsigned nPage;
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printf("Header at offset %d:\n", iOfst);
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print_decode_line(pHdr, 0, 4, "Header part 1 (3654616569)");
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print_decode_line(pHdr, 4, 4, "Header part 2 (547447767)");
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nPage =
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print_decode_line(pHdr, 8, 4, "page count");
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cksumNonce =
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print_decode_line(pHdr, 12, 4, "chksum nonce");
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print_decode_line(pHdr, 16, 4, "initial database size in pages");
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sectorSize =
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print_decode_line(pHdr, 20, 4, "sector size");
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pageSize =
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print_decode_line(pHdr, 24, 4, "page size");
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print_decode_line(pHdr, 28, 4, "zero");
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print_decode_line(pHdr, 32, 4, "zero");
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print_decode_line(pHdr, 36, 4, "zero");
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print_decode_line(pHdr, 40, 4, "zero");
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free(pHdr);
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return nPage;
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}
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static void print_page(int iOfst){
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unsigned char *aData;
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char zTitle[50];
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aData = read_content(pageSize+8, iOfst);
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sprintf(zTitle, "page number for page at offset %d", iOfst);
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print_decode_line(aData, 0, 4, zTitle);
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free(aData);
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}
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int main(int argc, char **argv){
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int rc;
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int nPage, cnt;
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int iOfst;
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if( argc!=2 ){
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fprintf(stderr,"Usage: %s FILENAME\n", argv[0]);
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exit(1);
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}
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db = fopen(argv[1], "rb");
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if( db==0 ){
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fprintf(stderr,"%s: can't open %s\n", argv[0], argv[1]);
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exit(1);
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}
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fseek(db, 0, SEEK_END);
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fileSize = ftell(db);
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printf("journal file size: %d bytes\n", fileSize);
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fseek(db, 0, SEEK_SET);
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iOfst = 0;
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while( iOfst<fileSize ){
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cnt = nPage = (int)decode_journal_header(iOfst);
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if( cnt==0 ){
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cnt = (fileSize - sectorSize)/(pageSize+8);
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}
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iOfst += sectorSize;
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while( cnt && iOfst<fileSize ){
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print_page(iOfst);
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iOfst += pageSize+8;
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}
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iOfst = (iOfst/sectorSize + 1)*sectorSize;
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}
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fclose(db);
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}
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