xref: /sqlite-3.40.0/tool/showdb.c (revision 962f9669)
1 /*
2 ** A utility for printing all or part of an SQLite database file.
3 */
4 #include <stdio.h>
5 #include <ctype.h>
6 #include <sys/types.h>
7 #include <sys/stat.h>
8 #include <fcntl.h>
9 
10 #if !defined(_MSC_VER)
11 #include <unistd.h>
12 #endif
13 
14 #include <stdlib.h>
15 #include <string.h>
16 #include "sqlite3.h"
17 
18 
19 static int pagesize = 1024;     /* Size of a database page */
20 static int db = -1;             /* File descriptor for reading the DB */
21 static int mxPage = 0;          /* Last page number */
22 static int perLine = 16;        /* HEX elements to print per line */
23 
24 typedef long long int i64;      /* Datatype for 64-bit integers */
25 
26 
27 /*
28 ** Convert the var-int format into i64.  Return the number of bytes
29 ** in the var-int.  Write the var-int value into *pVal.
30 */
31 static int decodeVarint(const unsigned char *z, i64 *pVal){
32   i64 v = 0;
33   int i;
34   for(i=0; i<8; i++){
35     v = (v<<7) + (z[i]&0x7f);
36     if( (z[i]&0x80)==0 ){ *pVal = v; return i+1; }
37   }
38   v = (v<<8) + (z[i]&0xff);
39   *pVal = v;
40   return 9;
41 }
42 
43 /*
44 ** Extract a big-endian 32-bit integer
45 */
46 static unsigned int decodeInt32(const unsigned char *z){
47   return (z[0]<<24) + (z[1]<<16) + (z[2]<<8) + z[3];
48 }
49 
50 /* Report an out-of-memory error and die.
51 */
52 static void out_of_memory(void){
53   fprintf(stderr,"Out of memory...\n");
54   exit(1);
55 }
56 
57 /*
58 ** Read content from the file.
59 **
60 ** Space to hold the content is obtained from malloc() and needs to be
61 ** freed by the caller.
62 */
63 static unsigned char *getContent(int ofst, int nByte){
64   unsigned char *aData;
65   aData = malloc(nByte+32);
66   if( aData==0 ) out_of_memory();
67   memset(aData, 0, nByte+32);
68   lseek(db, ofst, SEEK_SET);
69   read(db, aData, nByte);
70   return aData;
71 }
72 
73 /*
74 ** Print a range of bytes as hex and as ascii.
75 */
76 static unsigned char *print_byte_range(
77   int ofst,          /* First byte in the range of bytes to print */
78   int nByte,         /* Number of bytes to print */
79   int printOfst      /* Add this amount to the index on the left column */
80 ){
81   unsigned char *aData;
82   int i, j;
83   const char *zOfstFmt;
84 
85   if( ((printOfst+nByte)&~0xfff)==0 ){
86     zOfstFmt = " %03x: ";
87   }else if( ((printOfst+nByte)&~0xffff)==0 ){
88     zOfstFmt = " %04x: ";
89   }else if( ((printOfst+nByte)&~0xfffff)==0 ){
90     zOfstFmt = " %05x: ";
91   }else if( ((printOfst+nByte)&~0xffffff)==0 ){
92     zOfstFmt = " %06x: ";
93   }else{
94     zOfstFmt = " %08x: ";
95   }
96 
97   aData = getContent(ofst, nByte);
98   for(i=0; i<nByte; i += perLine){
99     fprintf(stdout, zOfstFmt, i+printOfst);
100     for(j=0; j<perLine; j++){
101       if( i+j>nByte ){
102         fprintf(stdout, "   ");
103       }else{
104         fprintf(stdout,"%02x ", aData[i+j]);
105       }
106     }
107     for(j=0; j<perLine; j++){
108       if( i+j>nByte ){
109         fprintf(stdout, " ");
110       }else{
111         fprintf(stdout,"%c", isprint(aData[i+j]) ? aData[i+j] : '.');
112       }
113     }
114     fprintf(stdout,"\n");
115   }
116   return aData;
117 }
118 
119 /*
120 ** Print an entire page of content as hex
121 */
122 static void print_page(int iPg){
123   int iStart;
124   unsigned char *aData;
125   iStart = (iPg-1)*pagesize;
126   fprintf(stdout, "Page %d:   (offsets 0x%x..0x%x)\n",
127           iPg, iStart, iStart+pagesize-1);
128   aData = print_byte_range(iStart, pagesize, 0);
129   free(aData);
130 }
131 
132 /* Print a line of decode output showing a 4-byte integer.
133 */
134 static void print_decode_line(
135   unsigned char *aData,      /* Content being decoded */
136   int ofst, int nByte,       /* Start and size of decode */
137   const char *zMsg           /* Message to append */
138 ){
139   int i, j;
140   int val = aData[ofst];
141   char zBuf[100];
142   sprintf(zBuf, " %03x: %02x", ofst, aData[ofst]);
143   i = strlen(zBuf);
144   for(j=1; j<4; j++){
145     if( j>=nByte ){
146       sprintf(&zBuf[i], "   ");
147     }else{
148       sprintf(&zBuf[i], " %02x", aData[ofst+j]);
149       val = val*256 + aData[ofst+j];
150     }
151     i += strlen(&zBuf[i]);
152   }
153   sprintf(&zBuf[i], "   %9d", val);
154   printf("%s  %s\n", zBuf, zMsg);
155 }
156 
157 /*
158 ** Decode the database header.
159 */
160 static void print_db_header(void){
161   unsigned char *aData;
162   aData = print_byte_range(0, 100, 0);
163   printf("Decoded:\n");
164   print_decode_line(aData, 16, 2, "Database page size");
165   print_decode_line(aData, 18, 1, "File format write version");
166   print_decode_line(aData, 19, 1, "File format read version");
167   print_decode_line(aData, 20, 1, "Reserved space at end of page");
168   print_decode_line(aData, 24, 4, "File change counter");
169   print_decode_line(aData, 28, 4, "Size of database in pages");
170   print_decode_line(aData, 32, 4, "Page number of first freelist page");
171   print_decode_line(aData, 36, 4, "Number of freelist pages");
172   print_decode_line(aData, 40, 4, "Schema cookie");
173   print_decode_line(aData, 44, 4, "Schema format version");
174   print_decode_line(aData, 48, 4, "Default page cache size");
175   print_decode_line(aData, 52, 4, "Largest auto-vac root page");
176   print_decode_line(aData, 56, 4, "Text encoding");
177   print_decode_line(aData, 60, 4, "User version");
178   print_decode_line(aData, 64, 4, "Incremental-vacuum mode");
179   print_decode_line(aData, 68, 4, "Application ID");
180   print_decode_line(aData, 72, 4, "meta[8]");
181   print_decode_line(aData, 76, 4, "meta[9]");
182   print_decode_line(aData, 80, 4, "meta[10]");
183   print_decode_line(aData, 84, 4, "meta[11]");
184   print_decode_line(aData, 88, 4, "meta[12]");
185   print_decode_line(aData, 92, 4, "Change counter for version number");
186   print_decode_line(aData, 96, 4, "SQLite version number");
187 }
188 
189 /*
190 ** Describe cell content.
191 */
192 static int describeContent(
193   unsigned char *a,       /* Cell content */
194   int nLocal,             /* Bytes in a[] */
195   char *zDesc             /* Write description here */
196 ){
197   int nDesc = 0;
198   int n, i, j;
199   i64 x, v;
200   const unsigned char *pData;
201   const unsigned char *pLimit;
202   char sep = ' ';
203 
204   pLimit = &a[nLocal];
205   n = decodeVarint(a, &x);
206   pData = &a[x];
207   a += n;
208   i = x - n;
209   while( i>0 && pData<=pLimit ){
210     n = decodeVarint(a, &x);
211     a += n;
212     i -= n;
213     nLocal -= n;
214     zDesc[0] = sep;
215     sep = ',';
216     nDesc++;
217     zDesc++;
218     if( x==0 ){
219       sprintf(zDesc, "*");     /* NULL is a "*" */
220     }else if( x>=1 && x<=6 ){
221       v = (signed char)pData[0];
222       pData++;
223       switch( x ){
224         case 6:  v = (v<<16) + (pData[0]<<8) + pData[1];  pData += 2;
225         case 5:  v = (v<<16) + (pData[0]<<8) + pData[1];  pData += 2;
226         case 4:  v = (v<<8) + pData[0];  pData++;
227         case 3:  v = (v<<8) + pData[0];  pData++;
228         case 2:  v = (v<<8) + pData[0];  pData++;
229       }
230       sprintf(zDesc, "%lld", v);
231     }else if( x==7 ){
232       sprintf(zDesc, "real");
233       pData += 8;
234     }else if( x==8 ){
235       sprintf(zDesc, "0");
236     }else if( x==9 ){
237       sprintf(zDesc, "1");
238     }else if( x>=12 ){
239       int size = (x-12)/2;
240       if( (x&1)==0 ){
241         sprintf(zDesc, "blob(%d)", size);
242       }else{
243         sprintf(zDesc, "txt(%d)", size);
244       }
245       pData += size;
246     }
247     j = strlen(zDesc);
248     zDesc += j;
249     nDesc += j;
250   }
251   return nDesc;
252 }
253 
254 /*
255 ** Compute the local payload size given the total payload size and
256 ** the page size.
257 */
258 static int localPayload(i64 nPayload, char cType){
259   int maxLocal;
260   int minLocal;
261   int surplus;
262   int nLocal;
263   if( cType==13 ){
264     /* Table leaf */
265     maxLocal = pagesize-35;
266     minLocal = (pagesize-12)*32/255-23;
267   }else{
268     maxLocal = (pagesize-12)*64/255-23;
269     minLocal = (pagesize-12)*32/255-23;
270   }
271   if( nPayload>maxLocal ){
272     surplus = minLocal + (nPayload-minLocal)%(pagesize-4);
273     if( surplus<=maxLocal ){
274       nLocal = surplus;
275     }else{
276       nLocal = minLocal;
277     }
278   }else{
279     nLocal = nPayload;
280   }
281   return nLocal;
282 }
283 
284 
285 /*
286 ** Create a description for a single cell.
287 **
288 ** The return value is the local cell size.
289 */
290 static int describeCell(
291   unsigned char cType,    /* Page type */
292   unsigned char *a,       /* Cell content */
293   int showCellContent,    /* Show cell content if true */
294   char **pzDesc           /* Store description here */
295 ){
296   int i;
297   int nDesc = 0;
298   int n = 0;
299   int leftChild;
300   i64 nPayload;
301   i64 rowid;
302   int nLocal;
303   static char zDesc[1000];
304   i = 0;
305   if( cType<=5 ){
306     leftChild = ((a[0]*256 + a[1])*256 + a[2])*256 + a[3];
307     a += 4;
308     n += 4;
309     sprintf(zDesc, "lx: %d ", leftChild);
310     nDesc = strlen(zDesc);
311   }
312   if( cType!=5 ){
313     i = decodeVarint(a, &nPayload);
314     a += i;
315     n += i;
316     sprintf(&zDesc[nDesc], "n: %lld ", nPayload);
317     nDesc += strlen(&zDesc[nDesc]);
318     nLocal = localPayload(nPayload, cType);
319   }else{
320     nPayload = nLocal = 0;
321   }
322   if( cType==5 || cType==13 ){
323     i = decodeVarint(a, &rowid);
324     a += i;
325     n += i;
326     sprintf(&zDesc[nDesc], "r: %lld ", rowid);
327     nDesc += strlen(&zDesc[nDesc]);
328   }
329   if( nLocal<nPayload ){
330     int ovfl;
331     unsigned char *b = &a[nLocal];
332     ovfl = ((b[0]*256 + b[1])*256 + b[2])*256 + b[3];
333     sprintf(&zDesc[nDesc], "ov: %d ", ovfl);
334     nDesc += strlen(&zDesc[nDesc]);
335     n += 4;
336   }
337   if( showCellContent && cType!=5 ){
338     nDesc += describeContent(a, nLocal, &zDesc[nDesc-1]);
339   }
340   *pzDesc = zDesc;
341   return nLocal+n;
342 }
343 
344 /*
345 ** Decode a btree page
346 */
347 static void decode_btree_page(
348   unsigned char *a,   /* Page content */
349   int pgno,           /* Page number */
350   int hdrSize,        /* Size of the page header.  0 or 100 */
351   char *zArgs         /* Flags to control formatting */
352 ){
353   const char *zType = "unknown";
354   int nCell;
355   int i, j;
356   int iCellPtr;
357   int showCellContent = 0;
358   int showMap = 0;
359   char *zMap = 0;
360   switch( a[0] ){
361     case 2:  zType = "index interior node";  break;
362     case 5:  zType = "table interior node";  break;
363     case 10: zType = "index leaf";           break;
364     case 13: zType = "table leaf";           break;
365   }
366   while( zArgs[0] ){
367     switch( zArgs[0] ){
368       case 'c': showCellContent = 1;  break;
369       case 'm': showMap = 1;          break;
370     }
371     zArgs++;
372   }
373   printf("Decode of btree page %d:\n", pgno);
374   print_decode_line(a, 0, 1, zType);
375   print_decode_line(a, 1, 2, "Offset to first freeblock");
376   print_decode_line(a, 3, 2, "Number of cells on this page");
377   nCell = a[3]*256 + a[4];
378   print_decode_line(a, 5, 2, "Offset to cell content area");
379   print_decode_line(a, 7, 1, "Fragmented byte count");
380   if( a[0]==2 || a[0]==5 ){
381     print_decode_line(a, 8, 4, "Right child");
382     iCellPtr = 12;
383   }else{
384     iCellPtr = 8;
385   }
386   if( nCell>0 ){
387     printf(" key: lx=left-child n=payload-size r=rowid\n");
388   }
389   if( showMap ){
390     zMap = malloc(pagesize);
391     memset(zMap, '.', pagesize);
392     memset(zMap, '1', hdrSize);
393     memset(&zMap[hdrSize], 'H', iCellPtr);
394     memset(&zMap[hdrSize+iCellPtr], 'P', 2*nCell);
395   }
396   for(i=0; i<nCell; i++){
397     int cofst = iCellPtr + i*2;
398     char *zDesc;
399     int n;
400 
401     cofst = a[cofst]*256 + a[cofst+1];
402     n = describeCell(a[0], &a[cofst-hdrSize], showCellContent, &zDesc);
403     if( showMap ){
404       char zBuf[30];
405       memset(&zMap[cofst], '*', n);
406       zMap[cofst] = '[';
407       zMap[cofst+n-1] = ']';
408       sprintf(zBuf, "%d", i);
409       j = strlen(zBuf);
410       if( j<=n-2 ) memcpy(&zMap[cofst+1], zBuf, j);
411     }
412     printf(" %03x: cell[%d] %s\n", cofst, i, zDesc);
413   }
414   if( showMap ){
415     for(i=0; i<pagesize; i+=64){
416       printf(" %03x: %.64s\n", i, &zMap[i]);
417     }
418     free(zMap);
419   }
420 }
421 
422 /*
423 ** Decode a freelist trunk page.
424 */
425 static void decode_trunk_page(
426   int pgno,             /* The page number */
427   int pagesize,         /* Size of each page */
428   int detail,           /* Show leaf pages if true */
429   int recursive         /* Follow the trunk change if true */
430 ){
431   int n, i;
432   unsigned char *a;
433   while( pgno>0 ){
434     a = getContent((pgno-1)*pagesize, pagesize);
435     printf("Decode of freelist trunk page %d:\n", pgno);
436     print_decode_line(a, 0, 4, "Next freelist trunk page");
437     print_decode_line(a, 4, 4, "Number of entries on this page");
438     if( detail ){
439       n = (int)decodeInt32(&a[4]);
440       for(i=0; i<n; i++){
441         unsigned int x = decodeInt32(&a[8+4*i]);
442         char zIdx[10];
443         sprintf(zIdx, "[%d]", i);
444         printf("  %5s %7u", zIdx, x);
445         if( i%5==4 ) printf("\n");
446       }
447       if( i%5!=0 ) printf("\n");
448     }
449     if( !recursive ){
450       pgno = 0;
451     }else{
452       pgno = (int)decodeInt32(&a[0]);
453     }
454     free(a);
455   }
456 }
457 
458 /*
459 ** A short text comment on the use of each page.
460 */
461 static char **zPageUse;
462 
463 /*
464 ** Add a comment on the use of a page.
465 */
466 static void page_usage_msg(int pgno, const char *zFormat, ...){
467   va_list ap;
468   char *zMsg;
469 
470   va_start(ap, zFormat);
471   zMsg = sqlite3_vmprintf(zFormat, ap);
472   va_end(ap);
473   if( pgno<=0 || pgno>mxPage ){
474     printf("ERROR: page %d out of range 1..%d: %s\n",
475             pgno, mxPage, zMsg);
476     sqlite3_free(zMsg);
477     return;
478   }
479   if( zPageUse[pgno]!=0 ){
480     printf("ERROR: page %d used multiple times:\n", pgno);
481     printf("ERROR:    previous: %s\n", zPageUse[pgno]);
482     printf("ERROR:    current:  %s\n", zMsg);
483     sqlite3_free(zPageUse[pgno]);
484   }
485   zPageUse[pgno] = zMsg;
486 }
487 
488 /*
489 ** Find overflow pages of a cell and describe their usage.
490 */
491 static void page_usage_cell(
492   unsigned char cType,    /* Page type */
493   unsigned char *a,       /* Cell content */
494   int pgno,               /* page containing the cell */
495   int cellno              /* Index of the cell on the page */
496 ){
497   int i;
498   int n = 0;
499   i64 nPayload;
500   i64 rowid;
501   int nLocal;
502   i = 0;
503   if( cType<=5 ){
504     a += 4;
505     n += 4;
506   }
507   if( cType!=5 ){
508     i = decodeVarint(a, &nPayload);
509     a += i;
510     n += i;
511     nLocal = localPayload(nPayload, cType);
512   }else{
513     nPayload = nLocal = 0;
514   }
515   if( cType==5 || cType==13 ){
516     i = decodeVarint(a, &rowid);
517     a += i;
518     n += i;
519   }
520   if( nLocal<nPayload ){
521     int ovfl = decodeInt32(a+nLocal);
522     int cnt = 0;
523     while( ovfl && (cnt++)<mxPage ){
524       page_usage_msg(ovfl, "overflow %d from cell %d of page %d",
525                      cnt, cellno, pgno);
526       a = getContent((ovfl-1)*pagesize, 4);
527       ovfl = decodeInt32(a);
528       free(a);
529     }
530   }
531 }
532 
533 
534 /*
535 ** Describe the usages of a b-tree page
536 */
537 static void page_usage_btree(
538   int pgno,             /* Page to describe */
539   int parent,           /* Parent of this page.  0 for root pages */
540   int idx,              /* Which child of the parent */
541   const char *zName     /* Name of the table */
542 ){
543   unsigned char *a;
544   const char *zType = "corrupt node";
545   int nCell;
546   int i;
547   int hdr = pgno==1 ? 100 : 0;
548 
549   if( pgno<=0 || pgno>mxPage ) return;
550   a = getContent((pgno-1)*pagesize, pagesize);
551   switch( a[hdr] ){
552     case 2:  zType = "interior node of index";  break;
553     case 5:  zType = "interior node of table";  break;
554     case 10: zType = "leaf of index";           break;
555     case 13: zType = "leaf of table";           break;
556   }
557   if( parent ){
558     page_usage_msg(pgno, "%s [%s], child %d of page %d",
559                    zType, zName, idx, parent);
560   }else{
561     page_usage_msg(pgno, "root %s [%s]", zType, zName);
562   }
563   nCell = a[hdr+3]*256 + a[hdr+4];
564   if( a[hdr]==2 || a[hdr]==5 ){
565     int cellstart = hdr+12;
566     unsigned int child;
567     for(i=0; i<nCell; i++){
568       int ofst;
569 
570       ofst = cellstart + i*2;
571       ofst = a[ofst]*256 + a[ofst+1];
572       child = decodeInt32(a+ofst);
573       page_usage_btree(child, pgno, i, zName);
574     }
575     child = decodeInt32(a+cellstart-4);
576     page_usage_btree(child, pgno, i, zName);
577   }
578   if( a[hdr]==2 || a[hdr]==10 || a[hdr]==13 ){
579     int cellstart = hdr + 8 + 4*(a[hdr]<=5);
580     for(i=0; i<nCell; i++){
581       int ofst;
582       ofst = cellstart + i*2;
583       ofst = a[ofst]*256 + a[ofst+1];
584       page_usage_cell(a[hdr], a+ofst, pgno, i);
585     }
586   }
587   free(a);
588 }
589 
590 /*
591 ** Determine page usage by the freelist
592 */
593 static void page_usage_freelist(int pgno){
594   unsigned char *a;
595   int cnt = 0;
596   int i;
597   int n;
598   int iNext;
599   int parent = 1;
600 
601   while( pgno>0 && pgno<=mxPage && (cnt++)<mxPage ){
602     page_usage_msg(pgno, "freelist trunk #%d child of %d", cnt, parent);
603     a = getContent((pgno-1)*pagesize, pagesize);
604     iNext = decodeInt32(a);
605     n = decodeInt32(a+4);
606     for(i=0; i<n; i++){
607       int child = decodeInt32(a + (i*4+8));
608       page_usage_msg(child, "freelist leaf, child %d of trunk page %d",
609                      i, pgno);
610     }
611     free(a);
612     parent = pgno;
613     pgno = iNext;
614   }
615 }
616 
617 /*
618 ** Determine pages used as PTRMAP pages
619 */
620 static void page_usage_ptrmap(unsigned char *a){
621   if( a[55] ){
622     int usable = pagesize - a[20];
623     int pgno = 2;
624     int perPage = usable/5;
625     while( pgno<=mxPage ){
626       page_usage_msg(pgno, "PTRMAP page covering %d..%d",
627                            pgno+1, pgno+perPage);
628       pgno += perPage + 1;
629     }
630   }
631 }
632 
633 /*
634 ** Try to figure out how every page in the database file is being used.
635 */
636 static void page_usage_report(const char *zDbName){
637   int i, j;
638   int rc;
639   sqlite3 *db;
640   sqlite3_stmt *pStmt;
641   unsigned char *a;
642   char zQuery[200];
643 
644   /* Avoid the pathological case */
645   if( mxPage<1 ){
646     printf("empty database\n");
647     return;
648   }
649 
650   /* Open the database file */
651   rc = sqlite3_open(zDbName, &db);
652   if( rc ){
653     printf("cannot open database: %s\n", sqlite3_errmsg(db));
654     sqlite3_close(db);
655     return;
656   }
657 
658   /* Set up global variables zPageUse[] and mxPage to record page
659   ** usages */
660   zPageUse = sqlite3_malloc( sizeof(zPageUse[0])*(mxPage+1) );
661   if( zPageUse==0 ) out_of_memory();
662   memset(zPageUse, 0, sizeof(zPageUse[0])*(mxPage+1));
663 
664   /* Discover the usage of each page */
665   a = getContent(0, 100);
666   page_usage_freelist(decodeInt32(a+32));
667   page_usage_ptrmap(a);
668   free(a);
669   page_usage_btree(1, 0, 0, "sqlite_master");
670   sqlite3_exec(db, "PRAGMA writable_schema=ON", 0, 0, 0);
671   for(j=0; j<2; j++){
672     sqlite3_snprintf(sizeof(zQuery), zQuery,
673              "SELECT type, name, rootpage FROM SQLITE_MASTER WHERE rootpage"
674              " ORDER BY rowid %s", j?"DESC":"");
675     rc = sqlite3_prepare_v2(db, zQuery, -1, &pStmt, 0);
676     if( rc==SQLITE_OK ){
677       while( sqlite3_step(pStmt)==SQLITE_ROW ){
678         int pgno = sqlite3_column_int(pStmt, 2);
679         page_usage_btree(pgno, 0, 0, (const char*)sqlite3_column_text(pStmt,1));
680       }
681     }else{
682       printf("ERROR: cannot query database: %s\n", sqlite3_errmsg(db));
683     }
684     rc = sqlite3_finalize(pStmt);
685     if( rc==SQLITE_OK ) break;
686   }
687   sqlite3_close(db);
688 
689   /* Print the report and free memory used */
690   for(i=1; i<=mxPage; i++){
691     printf("%5d: %s\n", i, zPageUse[i] ? zPageUse[i] : "???");
692     sqlite3_free(zPageUse[i]);
693   }
694   sqlite3_free(zPageUse);
695   zPageUse = 0;
696 }
697 
698 /*
699 ** Try to figure out how every page in the database file is being used.
700 */
701 static void ptrmap_coverage_report(const char *zDbName){
702   unsigned int pgno;
703   unsigned char *aHdr;
704   unsigned char *a;
705   int usable;
706   int perPage;
707   unsigned int i;
708 
709   /* Avoid the pathological case */
710   if( mxPage<1 ){
711     printf("empty database\n");
712     return;
713   }
714 
715   /* Make sure PTRMAPs are used in this database */
716   aHdr = getContent(0, 100);
717   if( aHdr[55]==0 ){
718     printf("database does not use PTRMAP pages\n");
719     return;
720   }
721   usable = pagesize - aHdr[20];
722   perPage = usable/5;
723   free(aHdr);
724   printf("%5d: root of sqlite_master\n", 1);
725   for(pgno=2; pgno<=mxPage; pgno += perPage+1){
726     printf("%5d: PTRMAP page covering %d..%d\n", pgno,
727            pgno+1, pgno+perPage);
728     a = getContent((pgno-1)*pagesize, usable);
729     for(i=0; i+5<=usable && pgno+1+i/5<=mxPage; i+=5){
730       const char *zType = "???";
731       unsigned int iFrom = decodeInt32(&a[i+1]);
732       switch( a[i] ){
733         case 1:  zType = "b-tree root page";        break;
734         case 2:  zType = "freelist page";           break;
735         case 3:  zType = "first page of overflow";  break;
736         case 4:  zType = "later page of overflow";  break;
737         case 5:  zType = "b-tree non-root page";    break;
738       }
739       printf("%5d: %s, parent=%u\n", pgno+1+i/5, zType, iFrom);
740     }
741     free(a);
742   }
743 }
744 
745 /*
746 ** Print a usage comment
747 */
748 static void usage(const char *argv0){
749   fprintf(stderr, "Usage %s FILENAME ?args...?\n\n", argv0);
750   fprintf(stderr,
751     "args:\n"
752     "    dbheader        Show database header\n"
753     "    pgidx           Index of how each page is used\n"
754     "    ptrmap          Show all PTRMAP page content\n"
755     "    NNN..MMM        Show hex of pages NNN through MMM\n"
756     "    NNN..end        Show hex of pages NNN through end of file\n"
757     "    NNNb            Decode btree page NNN\n"
758     "    NNNbc           Decode btree page NNN and show content\n"
759     "    NNNbm           Decode btree page NNN and show a layout map\n"
760     "    NNNt            Decode freelist trunk page NNN\n"
761     "    NNNtd           Show leaf freelist pages on the decode\n"
762     "    NNNtr           Recurisvely decode freelist starting at NNN\n"
763   );
764 }
765 
766 int main(int argc, char **argv){
767   struct stat sbuf;
768   unsigned char zPgSz[2];
769   if( argc<2 ){
770     usage(argv[0]);
771     exit(1);
772   }
773   db = open(argv[1], O_RDONLY);
774   if( db<0 ){
775     fprintf(stderr,"%s: can't open %s\n", argv[0], argv[1]);
776     exit(1);
777   }
778   zPgSz[0] = 0;
779   zPgSz[1] = 0;
780   lseek(db, 16, SEEK_SET);
781   read(db, zPgSz, 2);
782   pagesize = zPgSz[0]*256 + zPgSz[1]*65536;
783   if( pagesize==0 ) pagesize = 1024;
784   printf("Pagesize: %d\n", pagesize);
785   fstat(db, &sbuf);
786   mxPage = sbuf.st_size/pagesize;
787   printf("Available pages: 1..%d\n", mxPage);
788   if( argc==2 ){
789     int i;
790     for(i=1; i<=mxPage; i++) print_page(i);
791   }else{
792     int i;
793     for(i=2; i<argc; i++){
794       int iStart, iEnd;
795       char *zLeft;
796       if( strcmp(argv[i], "dbheader")==0 ){
797         print_db_header();
798         continue;
799       }
800       if( strcmp(argv[i], "pgidx")==0 ){
801         page_usage_report(argv[1]);
802         continue;
803       }
804       if( strcmp(argv[i], "ptrmap")==0 ){
805         ptrmap_coverage_report(argv[1]);
806         continue;
807       }
808       if( strcmp(argv[i], "help")==0 ){
809         usage(argv[0]);
810         continue;
811       }
812       if( !isdigit(argv[i][0]) ){
813         fprintf(stderr, "%s: unknown option: [%s]\n", argv[0], argv[i]);
814         continue;
815       }
816       iStart = strtol(argv[i], &zLeft, 0);
817       if( zLeft && strcmp(zLeft,"..end")==0 ){
818         iEnd = mxPage;
819       }else if( zLeft && zLeft[0]=='.' && zLeft[1]=='.' ){
820         iEnd = strtol(&zLeft[2], 0, 0);
821       }else if( zLeft && zLeft[0]=='b' ){
822         int ofst, nByte, hdrSize;
823         unsigned char *a;
824         if( iStart==1 ){
825           ofst = hdrSize = 100;
826           nByte = pagesize-100;
827         }else{
828           hdrSize = 0;
829           ofst = (iStart-1)*pagesize;
830           nByte = pagesize;
831         }
832         a = getContent(ofst, nByte);
833         decode_btree_page(a, iStart, hdrSize, &zLeft[1]);
834         free(a);
835         continue;
836       }else if( zLeft && zLeft[0]=='t' ){
837         int detail = 0;
838         int recursive = 0;
839         int i;
840         for(i=1; zLeft[i]; i++){
841           if( zLeft[i]=='r' ) recursive = 1;
842           if( zLeft[i]=='d' ) detail = 1;
843         }
844         decode_trunk_page(iStart, pagesize, detail, recursive);
845         continue;
846       }else{
847         iEnd = iStart;
848       }
849       if( iStart<1 || iEnd<iStart || iEnd>mxPage ){
850         fprintf(stderr,
851           "Page argument should be LOWER?..UPPER?.  Range 1 to %d\n",
852           mxPage);
853         exit(1);
854       }
855       while( iStart<=iEnd ){
856         print_page(iStart);
857         iStart++;
858       }
859     }
860   }
861   close(db);
862   return 0;
863 }
864