tool/enlargedb.c

   1 /*
   2 ** Try to enlarge an SQLite database by appending many unused pages.
   3 ** The resulting database will fail PRAGMA integrity_check due to the
   4 ** appended unused pages, but it should work otherwise.
   5 **
   6 ** Usage:
   7 **
   8 **        enlargedb  DATABASE   N
   9 **
  10 ** Adds N blank pages onto the end of DATABASE.  N can be decimal
  11 ** or hex.  The total number of pages after adding must be no greater
  12 ** than 4294967297
  13 */
  14 #include <stdio.h>
  15 #include <string.h>
  16 #include <stdlib.h>
  17
  18 int main(int argc, char **argv){
  19   char *zEnd;
  20   long long int toAppend;
  21   long long int currentSz;
  22   long long int newSz;
  23   FILE *f;
  24   size_t got;
  25   int pgsz;
  26   char zero = 0;
  27   unsigned char buf[100];
  28
  29   if( argc!=3 ) goto usage_error;
  30   toAppend = strtoll(argv[2], &zEnd, 0);
  31   if( zEnd==argv[2] || zEnd[0] ) goto usage_error;
  32   if( toAppend<1 ){
  33     fprintf(stderr, "N must be at least 1\n");
  34     exit(1);
  35   }
  36   f = fopen(argv[1], "r+b");
  37   if( f==0 ){
  38     fprintf(stderr, "cannot open \"%s\" for reading and writing\n", argv[1]);
  39     exit(1);
  40   }
  41   got = fread(buf, 1, sizeof(buf), f);
  42   if( got!=sizeof(buf) ) goto not_valid_db;
  43   if( strcmp((char*)buf,"SQLite format 3")!=0 ) goto not_valid_db;
  44   pgsz = (buf[16]<<8) + buf[17];
  45   if( pgsz==1 ) pgsz = 65536;
  46   if( pgsz<512 || pgsz>65536 || (pgsz&(pgsz-1))!=0 ) goto not_valid_db;
  47   currentSz = (buf[28]<<24) + (buf[29]<<16) + (buf[30]<<8) + buf[31];
  48   newSz = currentSz + toAppend;
  49   if( newSz > 0xffffffff ) newSz = 0xffffffff;
  50   buf[28] = (newSz>>24) & 0xff;
  51   buf[29] = (newSz>>16) & 0xff;
  52   buf[30] = (newSz>>8) & 0xff;
  53   buf[31] = newSz & 0xff;
  54   fseek(f, 28, SEEK_SET);
  55   fwrite(&buf[28],4,1,f);
  56   fseek(f, (long)(newSz*pgsz - 1), SEEK_SET);
  57   fwrite(&zero,1,1,f);
  58   fclose(f);
  59   return 0;
  60
  61 not_valid_db:
  62   fprintf(stderr,"not a valid database: %s\n", argv[1]);
  63   exit(1);
  64
  65 usage_error:
  66   fprintf(stderr,"Usage: %s DATABASE N\n", argv[0]);
  67   exit(1);
  68 }