Annotation of embedaddon/sqlite3/tool/offsets.c, revision 1.1
1.1 ! misho 1: /*
! 2: ** This program searches an SQLite database file for the lengths and
! 3: ** offsets for all TEXT or BLOB entries for a particular column of a
! 4: ** particular table. The rowid, size and offset for the column are
! 5: ** written to standard output. There are three arguments, which are the
! 6: ** name of the database file, the table, and the column.
! 7: */
! 8: #include "sqlite3.h"
! 9: #include <stdio.h>
! 10: #include <stdlib.h>
! 11: #include <stdarg.h>
! 12: #include <string.h>
! 13:
! 14: typedef unsigned char u8;
! 15: typedef struct GState GState;
! 16:
! 17: #define ArraySize(X) (sizeof(X)/sizeof(X[0]))
! 18:
! 19: /*
! 20: ** Global state information for this program.
! 21: */
! 22: struct GState {
! 23: char *zErr; /* Error message text */
! 24: FILE *f; /* Open database file */
! 25: int szPg; /* Page size for the database file */
! 26: int iRoot; /* Root page of the table */
! 27: int iCol; /* Column number for the column */
! 28: int pgno; /* Current page number */
! 29: u8 *aPage; /* Current page content */
! 30: u8 *aStack[20]; /* Page stack */
! 31: int aPgno[20]; /* Page number stack */
! 32: int nStack; /* Depth of stack */
! 33: int bTrace; /* True for tracing output */
! 34: };
! 35:
! 36: /*
! 37: ** Write an error.
! 38: */
! 39: static void ofstError(GState *p, const char *zFormat, ...){
! 40: va_list ap;
! 41: sqlite3_free(p->zErr);
! 42: va_start(ap, zFormat);
! 43: p->zErr = sqlite3_vmprintf(zFormat, ap);
! 44: va_end(ap);
! 45: }
! 46:
! 47: /*
! 48: ** Write a trace message
! 49: */
! 50: static void ofstTrace(GState *p, const char *zFormat, ...){
! 51: va_list ap;
! 52: if( p->bTrace ){
! 53: va_start(ap, zFormat);
! 54: vprintf(zFormat, ap);
! 55: va_end(ap);
! 56: }
! 57: }
! 58:
! 59: /*
! 60: ** Find the root page of the table and the column number of the column.
! 61: */
! 62: static void ofstRootAndColumn(
! 63: GState *p, /* Global state */
! 64: const char *zFile, /* Name of the database file */
! 65: const char *zTable, /* Name of the table */
! 66: const char *zColumn /* Name of the column */
! 67: ){
! 68: sqlite3 *db = 0;
! 69: sqlite3_stmt *pStmt = 0;
! 70: char *zSql = 0;
! 71: int rc;
! 72: if( p->zErr ) return;
! 73: rc = sqlite3_open(zFile, &db);
! 74: if( rc ){
! 75: ofstError(p, "cannot open database file \"%s\"", zFile);
! 76: goto rootAndColumn_exit;
! 77: }
! 78: zSql = sqlite3_mprintf("SELECT rootpage FROM sqlite_master WHERE name=%Q",
! 79: zTable);
! 80: rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
! 81: if( rc ) ofstError(p, "%s: [%s]", sqlite3_errmsg(db), zSql);
! 82: sqlite3_free(zSql);
! 83: if( p->zErr ) goto rootAndColumn_exit;
! 84: if( sqlite3_step(pStmt)!=SQLITE_ROW ){
! 85: ofstError(p, "cannot find table [%s]\n", zTable);
! 86: sqlite3_finalize(pStmt);
! 87: goto rootAndColumn_exit;
! 88: }
! 89: p->iRoot = sqlite3_column_int(pStmt , 0);
! 90: sqlite3_finalize(pStmt);
! 91:
! 92: p->iCol = -1;
! 93: zSql = sqlite3_mprintf("PRAGMA table_info(%Q)", zTable);
! 94: rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
! 95: if( rc ) ofstError(p, "%s: [%s}", sqlite3_errmsg(db), zSql);
! 96: sqlite3_free(zSql);
! 97: if( p->zErr ) goto rootAndColumn_exit;
! 98: while( sqlite3_step(pStmt)==SQLITE_ROW ){
! 99: const char *zCol = sqlite3_column_text(pStmt, 1);
! 100: if( strlen(zCol)==strlen(zColumn)
! 101: && sqlite3_strnicmp(zCol, zColumn, strlen(zCol))==0
! 102: ){
! 103: p->iCol = sqlite3_column_int(pStmt, 0);
! 104: break;
! 105: }
! 106: }
! 107: sqlite3_finalize(pStmt);
! 108: if( p->iCol<0 ){
! 109: ofstError(p, "no such column: %s.%s", zTable, zColumn);
! 110: goto rootAndColumn_exit;
! 111: }
! 112:
! 113: zSql = sqlite3_mprintf("PRAGMA page_size");
! 114: rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
! 115: if( rc ) ofstError(p, "%s: [%s]", sqlite3_errmsg(db), zSql);
! 116: sqlite3_free(zSql);
! 117: if( p->zErr ) goto rootAndColumn_exit;
! 118: if( sqlite3_step(pStmt)!=SQLITE_ROW ){
! 119: ofstError(p, "cannot find page size");
! 120: }else{
! 121: p->szPg = sqlite3_column_int(pStmt, 0);
! 122: }
! 123: sqlite3_finalize(pStmt);
! 124:
! 125: rootAndColumn_exit:
! 126: sqlite3_close(db);
! 127: return;
! 128: }
! 129:
! 130: /*
! 131: ** Pop a page from the stack
! 132: */
! 133: static void ofstPopPage(GState *p){
! 134: if( p->nStack<=0 ) return;
! 135: p->nStack--;
! 136: sqlite3_free(p->aStack[p->nStack]);
! 137: p->pgno = p->aPgno[p->nStack-1];
! 138: p->aPage = p->aStack[p->nStack-1];
! 139: }
! 140:
! 141:
! 142: /*
! 143: ** Push a new page onto the stack.
! 144: */
! 145: static void ofstPushPage(GState *p, int pgno){
! 146: u8 *pPage;
! 147: size_t got;
! 148: if( p->zErr ) return;
! 149: if( p->nStack >= ArraySize(p->aStack) ){
! 150: ofstError(p, "page stack overflow");
! 151: return;
! 152: }
! 153: p->aPgno[p->nStack] = pgno;
! 154: p->aStack[p->nStack] = pPage = sqlite3_malloc( p->szPg );
! 155: if( pPage==0 ){
! 156: fprintf(stderr, "out of memory\n");
! 157: exit(1);
! 158: }
! 159: p->nStack++;
! 160: p->aPage = pPage;
! 161: p->pgno = pgno;
! 162: fseek(p->f, (pgno-1)*p->szPg, SEEK_SET);
! 163: got = fread(pPage, 1, p->szPg, p->f);
! 164: if( got!=p->szPg ){
! 165: ofstError(p, "unable to read page %d", pgno);
! 166: ofstPopPage(p);
! 167: }
! 168: }
! 169:
! 170: /* Read a two-byte integer at the given offset into the current page */
! 171: static int ofst2byte(GState *p, int ofst){
! 172: int x = p->aPage[ofst];
! 173: return (x<<8) + p->aPage[ofst+1];
! 174: }
! 175:
! 176: /* Read a four-byte integer at the given offset into the current page */
! 177: static int ofst4byte(GState *p, int ofst){
! 178: int x = p->aPage[ofst];
! 179: x = (x<<8) + p->aPage[ofst+1];
! 180: x = (x<<8) + p->aPage[ofst+2];
! 181: x = (x<<8) + p->aPage[ofst+3];
! 182: return x;
! 183: }
! 184:
! 185: /* Read a variable-length integer. Update the offset */
! 186: static sqlite3_int64 ofstVarint(GState *p, int *pOfst){
! 187: sqlite3_int64 x = 0;
! 188: u8 *a = &p->aPage[*pOfst];
! 189: int n = 0;
! 190: while( n<8 && (a[0] & 0x80)!=0 ){
! 191: x = (x<<7) + (a[0] & 0x7f);
! 192: n++;
! 193: a++;
! 194: }
! 195: if( n==8 ){
! 196: x = (x<<8) + a[0];
! 197: }else{
! 198: x = (x<<7) + a[0];
! 199: }
! 200: *pOfst += (n+1);
! 201: return x;
! 202: }
! 203:
! 204: /* Return the absolute offset into a file for the given offset
! 205: ** into the current page */
! 206: static int ofstInFile(GState *p, int ofst){
! 207: return p->szPg*(p->pgno-1) + ofst;
! 208: }
! 209:
! 210: /* Return the size (in bytes) of the data corresponding to the
! 211: ** given serial code */
! 212: static int ofstSerialSize(int scode){
! 213: if( scode<5 ) return scode;
! 214: if( scode==5 ) return 6;
! 215: if( scode<8 ) return 8;
! 216: if( scode<12 ) return 0;
! 217: return (scode-12)/2;
! 218: }
! 219:
! 220: /* Forward reference */
! 221: static void ofstWalkPage(GState*, int);
! 222:
! 223: /* Walk an interior btree page */
! 224: static void ofstWalkInteriorPage(GState *p){
! 225: int nCell;
! 226: int i;
! 227: int ofst;
! 228: int iChild;
! 229:
! 230: nCell = ofst2byte(p, 3);
! 231: for(i=0; i<nCell; i++){
! 232: ofst = ofst2byte(p, 12+i*2);
! 233: iChild = ofst4byte(p, ofst);
! 234: ofstWalkPage(p, iChild);
! 235: if( p->zErr ) return;
! 236: }
! 237: ofstWalkPage(p, ofst4byte(p, 8));
! 238: }
! 239:
! 240: /* Walk a leaf btree page */
! 241: static void ofstWalkLeafPage(GState *p){
! 242: int nCell;
! 243: int i;
! 244: int ofst;
! 245: int nPayload;
! 246: sqlite3_int64 rowid;
! 247: int nHdr;
! 248: int j;
! 249: int scode;
! 250: int sz;
! 251: int dataOfst;
! 252: char zMsg[200];
! 253:
! 254: nCell = ofst2byte(p, 3);
! 255: for(i=0; i<nCell; i++){
! 256: ofst = ofst2byte(p, 8+i*2);
! 257: nPayload = ofstVarint(p, &ofst);
! 258: rowid = ofstVarint(p, &ofst);
! 259: if( nPayload > p->szPg-35 ){
! 260: sqlite3_snprintf(sizeof(zMsg), zMsg,
! 261: "# overflow rowid %lld", rowid);
! 262: printf("%s\n", zMsg);
! 263: continue;
! 264: }
! 265: dataOfst = ofst;
! 266: nHdr = ofstVarint(p, &ofst);
! 267: dataOfst += nHdr;
! 268: for(j=0; j<p->iCol; j++){
! 269: scode = ofstVarint(p, &ofst);
! 270: dataOfst += ofstSerialSize(scode);
! 271: }
! 272: scode = ofstVarint(p, &ofst);
! 273: sz = ofstSerialSize(scode);
! 274: sqlite3_snprintf(sizeof(zMsg), zMsg,
! 275: "rowid %12lld size %5d offset %8d",
! 276: rowid, sz, ofstInFile(p, dataOfst));
! 277: printf("%s\n", zMsg);
! 278: }
! 279: }
! 280:
! 281: /*
! 282: ** Output results from a single page.
! 283: */
! 284: static void ofstWalkPage(GState *p, int pgno){
! 285: if( p->zErr ) return;
! 286: ofstPushPage(p, pgno);
! 287: if( p->zErr ) return;
! 288: if( p->aPage[0]==5 ){
! 289: ofstWalkInteriorPage(p);
! 290: }else if( p->aPage[0]==13 ){
! 291: ofstWalkLeafPage(p);
! 292: }else{
! 293: ofstError(p, "page %d has a faulty type byte: %d", pgno, p->aPage[0]);
! 294: }
! 295: ofstPopPage(p);
! 296: }
! 297:
! 298: int main(int argc, char **argv){
! 299: GState g;
! 300: memset(&g, 0, sizeof(g));
! 301: if( argc>2 && strcmp(argv[1],"--trace")==0 ){
! 302: g.bTrace = 1;
! 303: argc--;
! 304: argv++;
! 305: }
! 306: if( argc!=4 ){
! 307: fprintf(stderr, "Usage: %s DATABASE TABLE COLUMN\n", *argv);
! 308: exit(1);
! 309: }
! 310: ofstRootAndColumn(&g, argv[1], argv[2], argv[3]);
! 311: if( g.zErr ){
! 312: fprintf(stderr, "%s\n", g.zErr);
! 313: exit(1);
! 314: }
! 315: ofstTrace(&g, "# szPg = %d\n", g.szPg);
! 316: ofstTrace(&g, "# iRoot = %d\n", g.iRoot);
! 317: ofstTrace(&g, "# iCol = %d\n", g.iCol);
! 318: g.f = fopen(argv[1], "rb");
! 319: if( g.f==0 ){
! 320: fprintf(stderr, "cannot open \"%s\"\n", argv[1]);
! 321: exit(1);
! 322: }
! 323: ofstWalkPage(&g, g.iRoot);
! 324: if( g.zErr ){
! 325: fprintf(stderr, "%s\n", g.zErr);
! 326: exit(1);
! 327: }
! 328: return 0;
! 329: }
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