1/*
2** A utility for printing an SQLite database journal.
3*/
4#include <stdio.h>
5#include <ctype.h>
6#include <stdlib.h>
7#include <string.h>
8
9/*
10** state information
11*/
12static int pageSize = 1024;
13static int sectorSize = 512;
14static FILE *db = 0;
15static int showPageContent = 0;
16static int fileSize = 0;
17static unsigned cksumNonce = 0;
18
19/* Report a memory allocation error */
20static void out_of_memory(void){
21  fprintf(stderr,"Out of memory...\n");
22  exit(1);
23}
24
25/*
26** Read N bytes of memory starting at iOfst into space obtained
27** from malloc().
28*/
29static char *read_content(int N, int iOfst){
30  int got;
31  char *pBuf = malloc(N);
32  if( pBuf==0 ) out_of_memory();
33  fseek(db, iOfst, SEEK_SET);
34  got = fread(pBuf, 1, N, db);
35  if( got<0 ){
36    fprintf(stderr, "I/O error reading %d bytes from %d\n", N, iOfst);
37    memset(pBuf, 0, N);
38  }else if( got<N ){
39    fprintf(stderr, "Short read: got only %d of %d bytes from %d\n",
40                     got, N, iOfst);
41    memset(&pBuf[got], 0, N-got);
42  }
43  return pBuf;
44}
45
46/* Print a line of decode output showing a 4-byte integer.
47*/
48static unsigned print_decode_line(
49  unsigned char *aData,      /* Content being decoded */
50  int ofst, int nByte,       /* Start and size of decode */
51  const char *zMsg           /* Message to append */
52){
53  int i, j;
54  unsigned val = aData[ofst];
55  char zBuf[100];
56  sprintf(zBuf, " %03x: %02x", ofst, aData[ofst]);
57  i = strlen(zBuf);
58  for(j=1; j<4; j++){
59    if( j>=nByte ){
60      sprintf(&zBuf[i], "   ");
61    }else{
62      sprintf(&zBuf[i], " %02x", aData[ofst+j]);
63      val = val*256 + aData[ofst+j];
64    }
65    i += strlen(&zBuf[i]);
66  }
67  sprintf(&zBuf[i], "   %10u", val);
68  printf("%s  %s\n", zBuf, zMsg);
69  return val;
70}
71
72/*
73** Read and print a journal header.  Store key information (page size, etc)
74** in global variables.
75*/
76static unsigned decode_journal_header(int iOfst){
77  char *pHdr = read_content(64, iOfst);
78  unsigned nPage;
79  printf("Header at offset %d:\n", iOfst);
80  print_decode_line(pHdr, 0, 4, "Header part 1 (3654616569)");
81  print_decode_line(pHdr, 4, 4, "Header part 2 (547447767)");
82  nPage =
83  print_decode_line(pHdr, 8, 4, "page count");
84  cksumNonce =
85  print_decode_line(pHdr, 12, 4, "chksum nonce");
86  print_decode_line(pHdr, 16, 4, "initial database size in pages");
87  sectorSize =
88  print_decode_line(pHdr, 20, 4, "sector size");
89  pageSize =
90  print_decode_line(pHdr, 24, 4, "page size");
91  print_decode_line(pHdr, 28, 4, "zero");
92  print_decode_line(pHdr, 32, 4, "zero");
93  print_decode_line(pHdr, 36, 4, "zero");
94  print_decode_line(pHdr, 40, 4, "zero");
95  free(pHdr);
96  return nPage;
97}
98
99static void print_page(int iOfst){
100  unsigned char *aData;
101  char zTitle[50];
102  aData = read_content(pageSize+8, iOfst);
103  sprintf(zTitle, "page number for page at offset %d", iOfst);
104  print_decode_line(aData, 0, 4, zTitle);
105  free(aData);
106}
107
108int main(int argc, char **argv){
109  int rc;
110  int nPage, cnt;
111  int iOfst;
112  if( argc!=2 ){
113    fprintf(stderr,"Usage: %s FILENAME\n", argv[0]);
114    exit(1);
115  }
116  db = fopen(argv[1], "rb");
117  if( db==0 ){
118    fprintf(stderr,"%s: can't open %s\n", argv[0], argv[1]);
119    exit(1);
120  }
121  fseek(db, 0, SEEK_END);
122  fileSize = ftell(db);
123  printf("journal file size: %d bytes\n", fileSize);
124  fseek(db, 0, SEEK_SET);
125  iOfst = 0;
126  while( iOfst<fileSize ){
127    cnt = nPage = (int)decode_journal_header(iOfst);
128    if( cnt==0 ){
129      cnt = (fileSize - sectorSize)/(pageSize+8);
130    }
131    iOfst += sectorSize;
132    while( cnt && iOfst<fileSize ){
133      print_page(iOfst);
134      iOfst += pageSize+8;
135    }
136    iOfst = (iOfst/sectorSize + 1)*sectorSize;
137  }
138  fclose(db);
139}
140