mirror of
https://github.com/tursodatabase/libsql.git
synced 2024-12-15 07:29:41 +00:00
69 lines
1.8 KiB
C
69 lines
1.8 KiB
C
/*
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** Try to enlarge an SQLite database by appending many unused pages.
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** The resulting database will fail PRAGMA integrity_check due to the
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** appended unused pages, but it should work otherwise.
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**
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** Usage:
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**
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** enlargedb DATABASE N
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**
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** Adds N blank pages onto the end of DATABASE. N can be decimal
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** or hex. The total number of pages after adding must be no greater
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** than 4294967297
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*/
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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int main(int argc, char **argv){
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char *zEnd;
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long long int toAppend;
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long long int currentSz;
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long long int newSz;
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FILE *f;
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size_t got;
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int pgsz;
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char zero = 0;
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unsigned char buf[100];
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if( argc!=3 ) goto usage_error;
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toAppend = strtoll(argv[2], &zEnd, 0);
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if( zEnd==argv[2] || zEnd[0] ) goto usage_error;
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if( toAppend<1 ){
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fprintf(stderr, "N must be at least 1\n");
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exit(1);
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}
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f = fopen(argv[1], "r+b");
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if( f==0 ){
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fprintf(stderr, "cannot open \"%s\" for reading and writing\n", argv[1]);
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exit(1);
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}
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got = fread(buf, 1, sizeof(buf), f);
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if( got!=sizeof(buf) ) goto not_valid_db;
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if( strcmp((char*)buf,"SQLite format 3")!=0 ) goto not_valid_db;
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pgsz = (buf[16]<<8) + buf[17];
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if( pgsz==1 ) pgsz = 65536;
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if( pgsz<512 || pgsz>65536 || (pgsz&(pgsz-1))!=0 ) goto not_valid_db;
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currentSz = (buf[28]<<24) + (buf[29]<<16) + (buf[30]<<8) + buf[31];
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newSz = currentSz + toAppend;
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if( newSz > 0xffffffff ) newSz = 0xffffffff;
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buf[28] = (newSz>>24) & 0xff;
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buf[29] = (newSz>>16) & 0xff;
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buf[30] = (newSz>>8) & 0xff;
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buf[31] = newSz & 0xff;
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fseek(f, 28, SEEK_SET);
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fwrite(&buf[28],4,1,f);
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fseek(f, (long)(newSz*pgsz - 1), SEEK_SET);
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fwrite(&zero,1,1,f);
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fclose(f);
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return 0;
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not_valid_db:
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fprintf(stderr,"not a valid database: %s\n", argv[1]);
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exit(1);
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usage_error:
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fprintf(stderr,"Usage: %s DATABASE N\n", argv[0]);
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exit(1);
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}
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