SQLite

/*
** A utility for printing all or part of an SQLite database file.
*/
#include <stdio.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include "sqlite3.h"


static int pagesize = 1024;     /* Size of a database page */
static int db = -1;             /* File descriptor for reading the DB */
static int mxPage = 0;          /* Last page number */
static int perLine = 16;        /* HEX elements to print per line */

      pgno = 0;
    }else{
      pgno = (int)decodeInt32(&a[0]);
    }
    free(a);
  }
}

/*
** A short text comment on the use of each page.
*/
static char **zPageUse;

/*
** Add a comment on the use of a page.
*/
static void page_usage_msg(int pgno, const char *zFormat, ...){
  va_list ap;
  char *zMsg;

  va_start(ap, zFormat);
  zMsg = sqlite3_vmprintf(zFormat, ap);
  va_end(ap);
  if( pgno<=0 || pgno>mxPage ){
    printf("ERROR: page %d out of bounds.  Range=1..%d.  Msg: %s\n",
            pgno, mxPage, zMsg);
    sqlite3_free(zMsg);
    return;
  }
  if( zPageUse[pgno]!=0 ){
    printf("ERROR: page %d used multiple times:\n", pgno);
    printf("ERROR:    previous: %s\n", zPageUse[pgno]);
    printf("ERROR:    current:  %s\n", zPageUse[pgno]);
    sqlite3_free(zPageUse[pgno]);
  }
  zPageUse[pgno] = zMsg;
}

/*
** Find overflow pages of a cell and describe their usage.
*/
static void page_usage_cell(
  unsigned char cType,    /* Page type */
  unsigned char *a,       /* Cell content */
  int pgno,               /* page containing the cell */
  int cellno              /* Index of the cell on the page */
){
  int i;
  int nDesc = 0;
  int n = 0;
  i64 nPayload;
  i64 rowid;
  int nLocal;
  i = 0;
  if( cType<=5 ){
    a += 4;
    n += 4;
  }
  if( cType!=5 ){
    i = decodeVarint(a, &nPayload);
    a += i;
    n += i;
    nLocal = localPayload(nPayload, cType);
  }else{
    nPayload = nLocal = 0;
  }
  if( cType==5 || cType==13 ){
    i = decodeVarint(a, &rowid);
    a += i;
    n += i;
  }
  if( nLocal<nPayload ){
    int ovfl = decodeInt32(a+nLocal);
    int cnt = 0;
    while( ovfl && (cnt++)<mxPage ){
      page_usage_msg(ovfl, "overflow %d from cell %d of page %d",
                     cnt, cellno, pgno);
      a = getContent((ovfl-1)*pagesize, 4);
      ovfl = decodeInt32(a);
      free(a);
    }
  }
}


/*
** Describe the usages of a b-tree page
*/
static void page_usage_btree(
  int pgno,             /* Page to describe */
  int parent,           /* Parent of this page.  0 for root pages */
  int idx,              /* Which child of the parent */
  const char *zName     /* Name of the table */
){
  unsigned char *a;
  const char *zType = "corrupt node";
  int nCell;
  int i;
  int hdr = pgno==1 ? 100 : 0;

  if( pgno<=0 || pgno>mxPage ) return;
  a = getContent((pgno-1)*pagesize, pagesize);
  switch( a[hdr] ){
    case 2:  zType = "interior node of index";  break;
    case 5:  zType = "interior node of table";  break;
    case 10: zType = "leaf of index";           break;
    case 13: zType = "leaf of table";           break;
  }
  if( parent ){
    page_usage_msg(pgno, "%s [%s], child %d of page %d",
                   zType, zName, idx, parent);
  }else{
    page_usage_msg(pgno, "root %s [%s]", zType, zName);
  }
  nCell = a[hdr+3]*256 + a[hdr+4];
  if( a[hdr]==2 || a[hdr]==5 ){
    int cellstart = hdr+12;
    unsigned int child;
    for(i=0; i<nCell; i++){
      int ofst;

      ofst = cellstart + i*2;
      ofst = a[ofst]*256 + a[ofst+1];
      child = decodeInt32(a+ofst);
      page_usage_btree(child, pgno, i, zName);
    }
    child = decodeInt32(a+cellstart-4);
    page_usage_btree(child, pgno, i, zName);
  }
  if( a[hdr]==2 || a[hdr]==10 || a[hdr]==13 ){
    int cellstart = hdr + 8 + 4*(a[hdr]<=5);
    for(i=0; i<nCell; i++){
      int ofst;
      ofst = cellstart + i*2;
      ofst = a[ofst]*256 + a[ofst+1];
      page_usage_cell(a[hdr], a+ofst, pgno, i);
    }
  }
  free(a);
}

/*
** Determine page usage by the freelist
*/
static void page_usage_freelist(int pgno){
  unsigned char *a;
  int cnt = 0;
  int i;
  int n;
  int iNext;
  int parent = 1;

  while( pgno>0 && pgno<=mxPage && (cnt++)<mxPage ){
    page_usage_msg(pgno, "freelist trunk #%d child of %d", cnt, parent);
    a = getContent((pgno-1)*pagesize, pagesize);
    iNext = decodeInt32(a);
    n = decodeInt32(a+4);
    for(i=0; i<n; i++){
      int child = decodeInt32(a + (i*4+8));
      page_usage_msg(child, "freelist leaf, child %d of trunk page %d",
                     i, pgno);
    }
    free(a);
    parent = pgno;
    pgno = iNext;
  }
}

/*
** Try to figure out how every page in the database file is being used.
*/
static void page_usage_report(const char *zDbName){
  int i;
  int rc;
  sqlite3 *db;
  sqlite3_stmt *pStmt;
  unsigned char *a;

  /* Avoid the pathological case */
  if( mxPage<1 ){
    printf("empty database\n");
    return;
  }

  /* Open the database file */
  rc = sqlite3_open(zDbName, &db);
  if( rc ){
    printf("cannot open database: %s\n", sqlite3_errmsg(db));
    sqlite3_close(db);
    return;
  }

  /* Set up global variables zPageUse[] and mxPage to record page
  ** usages */
  zPageUse = sqlite3_malloc( sizeof(zPageUse[0])*(mxPage+1) );
  if( zPageUse==0 ) out_of_memory();
  memset(zPageUse, 0, sizeof(zPageUse[0])*(mxPage+1));

  /* Discover the usage of each page */
  a = getContent(0, 100);
  page_usage_freelist(decodeInt32(a+32));
  free(a);
  page_usage_btree(1, 0, 0, "sqlite_master");
  rc = sqlite3_prepare_v2(db,
           "SELECT type, name, rootpage FROM SQLITE_MASTER WHERE rootpage",
           -1, &pStmt, 0);
  if( rc==SQLITE_OK ){
    while( sqlite3_step(pStmt)==SQLITE_ROW ){
      int pgno = sqlite3_column_int(pStmt, 2);
      page_usage_btree(pgno, 0, 0, sqlite3_column_text(pStmt, 1));
    }
  }
  sqlite3_finalize(pStmt);
  sqlite3_close(db);

  /* Print the report and free memory used */
  for(i=1; i<=mxPage; i++){
    printf("%5d: %s\n", i, zPageUse[i] ? zPageUse[i] : "???");
    sqlite3_free(zPageUse[i]);
  }
  sqlite3_free(zPageUse);
  zPageUse = 0;
}

/*
** Print a usage comment
*/
static void usage(const char *argv0){
  fprintf(stderr, "Usage %s FILENAME ?args...?\n\n", argv0);
  fprintf(stderr,
    "args:\n"
    "    dbheader        Show database header\n"
    "    pgidx           Index of how each page is used\n"
    "    NNN..MMM        Show hex of pages NNN through MMM\n"
    "    NNN..end        Show hex of pages NNN through end of file\n"
    "    NNNb            Decode btree page NNN\n"
    "    NNNbc           Decode btree page NNN and show content\n"
    "    NNNbm           Decode btree page NNN and show a layout map\n"
    "    NNNt            Decode freelist trunk page NNN\n"
    "    NNNtd           Show leaf freelist pages on the decode\n"

    int i;
    for(i=2; i<argc; i++){
      int iStart, iEnd;
      char *zLeft;
      if( strcmp(argv[i], "dbheader")==0 ){
        print_db_header();
        continue;
      }
      if( strcmp(argv[i], "pgidx")==0 ){
        page_usage_report(argv[1]);
        continue;
      }
      if( !isdigit(argv[i][0]) ){
        fprintf(stderr, "%s: unknown option: [%s]\n", argv[0], argv[i]);
        continue;
      }
      iStart = strtol(argv[i], &zLeft, 0);
      if( zLeft && strcmp(zLeft,"..end")==0 ){