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48e080b26c033dc92f331ccdab1ae3f983d6ef1d
sqlite/tool/showwal.c
drh 1590d10bc9 Add btree-page decoding logic to showwal.c. Commands of the form: 
"showwal $FILE 123bmc" show the content of the btree page in frame
123.  "b" means decode the btree.  "c" means show cell content.
"m" means give a map of the btree page.

FossilOrigin-Name: 93b159da5d2570946fdcd7da120bf7eb82b840f3
2013-01-25 15:59:55 +00:00

591 lines
15 KiB
C
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/*
** A utility for printing content from a write-ahead log 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>
static int pagesize = 1024; /* Size of a database page */
static int fd = -1; /* File descriptor for reading the WAL file */
static int mxFrame = 0; /* Last frame */
static int perLine = 16; /* HEX elements to print per line */
typedef long long int i64; /* Datatype for 64-bit integers */
/* Information for computing the checksum */
typedef struct Cksum Cksum;
struct Cksum {
int bSwap; /* True to do byte swapping on 32-bit words */
unsigned s0, s1; /* Current checksum value */
};
/*
** extract a 32-bit big-endian integer
*/
static unsigned int getInt32(const unsigned char *a){
unsigned int x = (a[0]<<24) + (a[1]<<16) + (a[2]<<8) + a[3];
return x;
}
/*
** Swap bytes on a 32-bit unsigned integer
*/
static unsigned int swab32(unsigned int x){
return (((x)&0x000000FF)<<24) + (((x)&0x0000FF00)<<8)
+ (((x)&0x00FF0000)>>8) + (((x)&0xFF000000)>>24);
}
/* Extend the checksum. Reinitialize the checksum if bInit is true.
*/
static void extendCksum(
Cksum *pCksum,
unsigned char *aData,
unsigned int nByte,
int bInit
){
unsigned int *a32;
if( bInit ){
int a = 0;
*((char*)&a) = 1;
if( a==1 ){
/* Host is little-endian */
pCksum->bSwap = getInt32(aData)!=0x377f0682;
}else{
/* Host is big-endian */
pCksum->bSwap = getInt32(aData)!=0x377f0683;
}
pCksum->s0 = 0;
pCksum->s1 = 0;
}
a32 = (unsigned int*)aData;
while( nByte>0 ){
unsigned int x0 = a32[0];
unsigned int x1 = a32[1];
if( pCksum->bSwap ){
x0 = swab32(x0);
x1 = swab32(x1);
}
pCksum->s0 += x0 + pCksum->s1;
pCksum->s1 += x1 + pCksum->s0;
nByte -= 8;
a32 += 2;
}
}
/*
** Convert the var-int format into i64. Return the number of bytes
** in the var-int. Write the var-int value into *pVal.
*/
static int decodeVarint(const unsigned char *z, i64 *pVal){
i64 v = 0;
int i;
for(i=0; i<8; i++){
v = (v<<7) + (z[i]&0x7f);
if( (z[i]&0x80)==0 ){ *pVal = v; return i+1; }
}
v = (v<<8) + (z[i]&0xff);
*pVal = v;
return 9;
}
/* Report an out-of-memory error and die.
*/
static void out_of_memory(void){
fprintf(stderr,"Out of memory...\n");
exit(1);
}
/*
** Read content from the file.
**
** Space to hold the content is obtained from malloc() and needs to be
** freed by the caller.
*/
static unsigned char *getContent(int ofst, int nByte){
unsigned char *aData;
aData = malloc(nByte);
if( aData==0 ) out_of_memory();
lseek(fd, ofst, SEEK_SET);
read(fd, aData, nByte);
return aData;
}
/*
** Print a range of bytes as hex and as ascii.
*/
static void print_byte_range(
int ofst, /* First byte in the range of bytes to print */
int nByte, /* Number of bytes to print */
unsigned char *aData, /* Content to print */
int printOfst /* Add this amount to the index on the left column */
){
int i, j;
const char *zOfstFmt;
if( ((printOfst+nByte)&~0xfff)==0 ){
zOfstFmt = " %03x: ";
}else if( ((printOfst+nByte)&~0xffff)==0 ){
zOfstFmt = " %04x: ";
}else if( ((printOfst+nByte)&~0xfffff)==0 ){
zOfstFmt = " %05x: ";
}else if( ((printOfst+nByte)&~0xffffff)==0 ){
zOfstFmt = " %06x: ";
}else{
zOfstFmt = " %08x: ";
}
for(i=0; i<nByte; i += perLine){
fprintf(stdout, zOfstFmt, i+printOfst);
for(j=0; j<perLine; j++){
if( i+j>nByte ){
fprintf(stdout, " ");
}else{
fprintf(stdout,"%02x ", aData[i+j]);
}
}
for(j=0; j<perLine; j++){
if( i+j>nByte ){
fprintf(stdout, " ");
}else{
fprintf(stdout,"%c", isprint(aData[i+j]) ? aData[i+j] : '.');
}
}
fprintf(stdout,"\n");
}
}
/* Print a line of decode output showing a 4-byte integer.
*/
static void print_decode_line(
unsigned char *aData, /* Content being decoded */
int ofst, int nByte, /* Start and size of decode */
int asHex, /* If true, output value as hex */
const char *zMsg /* Message to append */
){
int i, j;
int val = aData[ofst];
char zBuf[100];
sprintf(zBuf, " %03x: %02x", ofst, aData[ofst]);
i = strlen(zBuf);
for(j=1; j<4; j++){
if( j>=nByte ){
sprintf(&zBuf[i], " ");
}else{
sprintf(&zBuf[i], " %02x", aData[ofst+j]);
val = val*256 + aData[ofst+j];
}
i += strlen(&zBuf[i]);
}
if( asHex ){
sprintf(&zBuf[i], " 0x%08x", val);
}else{
sprintf(&zBuf[i], " %9d", val);
}
printf("%s %s\n", zBuf, zMsg);
}
/*
** Print an entire page of content as hex
*/
static void print_frame(int iFrame){
int iStart;
unsigned char *aData;
iStart = 32 + (iFrame-1)*(pagesize+24);
fprintf(stdout, "Frame %d: (offsets 0x%x..0x%x)\n",
iFrame, iStart, iStart+pagesize+24);
aData = getContent(iStart, pagesize+24);
print_decode_line(aData, 0, 4, 0, "Page number");
print_decode_line(aData, 4, 4, 0, "DB size, or 0 for non-commit");
print_decode_line(aData, 8, 4, 1, "Salt-1");
print_decode_line(aData,12, 4, 1, "Salt-2");
print_decode_line(aData,16, 4, 1, "Checksum-1");
print_decode_line(aData,20, 4, 1, "Checksum-2");
print_byte_range(iStart+24, pagesize, aData+24, 0);
free(aData);
}
/*
** Summarize a single frame on a single line.
*/
static void print_oneline_frame(int iFrame, Cksum *pCksum){
int iStart;
unsigned char *aData;
unsigned int s0, s1;
iStart = 32 + (iFrame-1)*(pagesize+24);
aData = getContent(iStart, 24);
extendCksum(pCksum, aData, 8, 0);
extendCksum(pCksum, getContent(iStart+24, pagesize), pagesize, 0);
s0 = getInt32(aData+16);
s1 = getInt32(aData+20);
fprintf(stdout, "Frame %4d: %6d %6d 0x%08x,%08x 0x%08x,%08x %s\n",
iFrame,
getInt32(aData),
getInt32(aData+4),
getInt32(aData+8),
getInt32(aData+12),
s0,
s1,
(s0==pCksum->s0 && s1==pCksum->s1) ? "" : "cksum-fail"
);
/* Reset the checksum so that a single frame checksum failure will not
** cause all subsequent frames to also show a failure. */
pCksum->s0 = s0;
pCksum->s1 = s1;
free(aData);
}
/*
** Decode the WAL header.
*/
static void print_wal_header(Cksum *pCksum){
unsigned char *aData;
aData = getContent(0, 32);
if( pCksum ){
extendCksum(pCksum, aData, 24, 1);
printf("Checksum byte order: %s\n", pCksum->bSwap ? "swapped" : "native");
}
printf("WAL Header:\n");
print_decode_line(aData, 0, 4,1,"Magic. 0x377f0682 (le) or 0x377f0683 (be)");
print_decode_line(aData, 4, 4, 0, "File format");
print_decode_line(aData, 8, 4, 0, "Database page size");
print_decode_line(aData, 12,4, 0, "Checkpoint sequence number");
print_decode_line(aData, 16,4, 1, "Salt-1");
print_decode_line(aData, 20,4, 1, "Salt-2");
print_decode_line(aData, 24,4, 1, "Checksum-1");
print_decode_line(aData, 28,4, 1, "Checksum-2");
if( pCksum ){
if( pCksum->s0!=getInt32(aData+24) ){
printf("**** cksum-1 mismatch: 0x%08x\n", pCksum->s0);
}
if( pCksum->s1!=getInt32(aData+28) ){
printf("**** cksum-2 mismatch: 0x%08x\n", pCksum->s1);
}
}
free(aData);
}
/*
** Describe cell content.
*/
static int describeContent(
unsigned char *a, /* Cell content */
int nLocal, /* Bytes in a[] */
char *zDesc /* Write description here */
){
int nDesc = 0;
int n, i, j;
i64 x, v;
const unsigned char *pData;
const unsigned char *pLimit;
char sep = ' ';
pLimit = &a[nLocal];
n = decodeVarint(a, &x);
pData = &a[x];
a += n;
i = x - n;
while( i>0 && pData<=pLimit ){
n = decodeVarint(a, &x);
a += n;
i -= n;
nLocal -= n;
zDesc[0] = sep;
sep = ',';
nDesc++;
zDesc++;
if( x==0 ){
sprintf(zDesc, "*"); /* NULL is a "*" */
}else if( x>=1 && x<=6 ){
v = (signed char)pData[0];
pData++;
switch( x ){
case 6: v = (v<<16) + (pData[0]<<8) + pData[1]; pData += 2;
case 5: v = (v<<16) + (pData[0]<<8) + pData[1]; pData += 2;
case 4: v = (v<<8) + pData[0]; pData++;
case 3: v = (v<<8) + pData[0]; pData++;
case 2: v = (v<<8) + pData[0]; pData++;
}
sprintf(zDesc, "%lld", v);
}else if( x==7 ){
sprintf(zDesc, "real");
pData += 8;
}else if( x==8 ){
sprintf(zDesc, "0");
}else if( x==9 ){
sprintf(zDesc, "1");
}else if( x>=12 ){
int size = (x-12)/2;
if( (x&1)==0 ){
sprintf(zDesc, "blob(%d)", size);
}else{
sprintf(zDesc, "txt(%d)", size);
}
pData += size;
}
j = strlen(zDesc);
zDesc += j;
nDesc += j;
}
return nDesc;
}
/*
** Compute the local payload size given the total payload size and
** the page size.
*/
static int localPayload(i64 nPayload, char cType){
int maxLocal;
int minLocal;
int surplus;
int nLocal;
if( cType==13 ){
/* Table leaf */
maxLocal = pagesize-35;
minLocal = (pagesize-12)*32/255-23;
}else{
maxLocal = (pagesize-12)*64/255-23;
minLocal = (pagesize-12)*32/255-23;
}
if( nPayload>maxLocal ){
surplus = minLocal + (nPayload-minLocal)%(pagesize-4);
if( surplus<=maxLocal ){
nLocal = surplus;
}else{
nLocal = minLocal;
}
}else{
nLocal = nPayload;
}
return nLocal;
}
/*
** Create a description for a single cell.
**
** The return value is the local cell size.
*/
static int describeCell(
unsigned char cType, /* Page type */
unsigned char *a, /* Cell content */
int showCellContent, /* Show cell content if true */
char **pzDesc /* Store description here */
){
int i;
int nDesc = 0;
int n = 0;
int leftChild;
i64 nPayload;
i64 rowid;
int nLocal;
static char zDesc[1000];
i = 0;
if( cType<=5 ){
leftChild = ((a[0]*256 + a[1])*256 + a[2])*256 + a[3];
a += 4;
n += 4;
sprintf(zDesc, "lx: %d ", leftChild);
nDesc = strlen(zDesc);
}
if( cType!=5 ){
i = decodeVarint(a, &nPayload);
a += i;
n += i;
sprintf(&zDesc[nDesc], "n: %lld ", nPayload);
nDesc += strlen(&zDesc[nDesc]);
nLocal = localPayload(nPayload, cType);
}else{
nPayload = nLocal = 0;
}
if( cType==5 || cType==13 ){
i = decodeVarint(a, &rowid);
a += i;
n += i;
sprintf(&zDesc[nDesc], "r: %lld ", rowid);
nDesc += strlen(&zDesc[nDesc]);
}
if( nLocal<nPayload ){
int ovfl;
unsigned char *b = &a[nLocal];
ovfl = ((b[0]*256 + b[1])*256 + b[2])*256 + b[3];
sprintf(&zDesc[nDesc], "ov: %d ", ovfl);
nDesc += strlen(&zDesc[nDesc]);
n += 4;
}
if( showCellContent && cType!=5 ){
nDesc += describeContent(a, nLocal, &zDesc[nDesc-1]);
}
*pzDesc = zDesc;
return nLocal+n;
}
/*
** Decode a btree page
*/
static void decode_btree_page(
unsigned char *a, /* Content of the btree page to be decoded */
int pgno, /* Page number */
int hdrSize, /* Size of the page1-header in bytes */
const char *zArgs /* Flags to control formatting */
){
const char *zType = "unknown";
int nCell;
int i, j;
int iCellPtr;
int showCellContent = 0;
int showMap = 0;
char *zMap = 0;
switch( a[0] ){
case 2: zType = "index interior node"; break;
case 5: zType = "table interior node"; break;
case 10: zType = "index leaf"; break;
case 13: zType = "table leaf"; break;
}
while( zArgs[0] ){
switch( zArgs[0] ){
case 'c': showCellContent = 1; break;
case 'm': showMap = 1; break;
}
zArgs++;
}
printf("Decode of btree page %d:\n", pgno);
print_decode_line(a, 0, 1, 0, zType);
print_decode_line(a, 1, 2, 0, "Offset to first freeblock");
print_decode_line(a, 3, 2, 0, "Number of cells on this page");
nCell = a[3]*256 + a[4];
print_decode_line(a, 5, 2, 0, "Offset to cell content area");
print_decode_line(a, 7, 1, 0, "Fragmented byte count");
if( a[0]==2 || a[0]==5 ){
print_decode_line(a, 8, 4, 0, "Right child");
iCellPtr = 12;
}else{
iCellPtr = 8;
}
if( nCell>0 ){
printf(" key: lx=left-child n=payload-size r=rowid\n");
}
if( showMap ){
zMap = malloc(pagesize);
memset(zMap, '.', pagesize);
memset(zMap, '1', hdrSize);
memset(&zMap[hdrSize], 'H', iCellPtr);
memset(&zMap[hdrSize+iCellPtr], 'P', 2*nCell);
}
for(i=0; i<nCell; i++){
int cofst = iCellPtr + i*2;
char *zDesc;
int n;
cofst = a[cofst]*256 + a[cofst+1];
n = describeCell(a[0], &a[cofst-hdrSize], showCellContent, &zDesc);
if( showMap ){
char zBuf[30];
memset(&zMap[cofst], '*', n);
zMap[cofst] = '[';
zMap[cofst+n-1] = ']';
sprintf(zBuf, "%d", i);
j = strlen(zBuf);
if( j<=n-2 ) memcpy(&zMap[cofst+1], zBuf, j);
}
printf(" %03x: cell[%d] %s\n", cofst, i, zDesc);
}
if( showMap ){
for(i=0; i<pagesize; i+=64){
printf(" %03x: %.64s\n", i, &zMap[i]);
}
free(zMap);
}
}
int main(int argc, char **argv){
struct stat sbuf;
unsigned char zPgSz[2];
if( argc<2 ){
fprintf(stderr,"Usage: %s FILENAME ?PAGE? ...\n", argv[0]);
exit(1);
}
fd = open(argv[1], O_RDONLY);
if( fd<0 ){
fprintf(stderr,"%s: can't open %s\n", argv[0], argv[1]);
exit(1);
}
zPgSz[0] = 0;
zPgSz[1] = 0;
lseek(fd, 10, SEEK_SET);
read(fd, zPgSz, 2);
pagesize = zPgSz[0]*256 + zPgSz[1];
if( pagesize==0 ) pagesize = 1024;
printf("Pagesize: %d\n", pagesize);
fstat(fd, &sbuf);
if( sbuf.st_size<32 ){
printf("file too small to be a WAL\n");
return 0;
}
mxFrame = (sbuf.st_size - 32)/(pagesize + 24);
printf("Available pages: 1..%d\n", mxFrame);
if( argc==2 ){
int i;
Cksum x;
print_wal_header(&x);
for(i=1; i<=mxFrame; i++){
print_oneline_frame(i, &x);
}
}else{
int i;
for(i=2; i<argc; i++){
int iStart, iEnd;
char *zLeft;
if( strcmp(argv[i], "header")==0 ){
print_wal_header(0);
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 ){
iEnd = mxFrame;
}else if( zLeft && zLeft[0]=='.' && zLeft[1]=='.' ){
iEnd = strtol(&zLeft[2], 0, 0);
}else if( zLeft && zLeft[0]=='b' ){
int ofst, nByte, hdrSize;
unsigned char *a;
if( iStart==1 ){
hdrSize = 100;
ofst = hdrSize = 100;
nByte = pagesize-100;
}else{
hdrSize = 0;
ofst = (iStart-1)*pagesize;
nByte = pagesize;
}
ofst = 32 + hdrSize + (iStart-1)*(pagesize+24) + 24;
a = getContent(ofst, nByte);
decode_btree_page(a, iStart, hdrSize, zLeft+1);
free(a);
continue;
}else{
iEnd = iStart;
}
if( iStart<1 || iEnd<iStart || iEnd>mxFrame ){
fprintf(stderr,
"Page argument should be LOWER?..UPPER?. Range 1 to %d\n",
mxFrame);
exit(1);
}
while( iStart<=iEnd ){
print_frame(iStart);
iStart++;
}
}
}
close(fd);
return 0;
}
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