From 7bb481fda9ecb134804b49c2ce77ca28f7eea583 Mon Sep 17 00:00:00 2001
From: Hans-Christoph Steiner <hans@eds.org>
Date: Fri, 30 Mar 2012 20:42:12 -0400
Subject: Imported Upstream version 2.0.3

---
 tool/showwal.c | 355 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 355 insertions(+)
 create mode 100644 tool/showwal.c

(limited to 'tool/showwal.c')

diff --git a/tool/showwal.c b/tool/showwal.c
new file mode 100644
index 0000000..ae25a59
--- /dev/null
+++ b/tool/showwal.c
@@ -0,0 +1,355 @@
+/*
+** 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 */
+
+
+/*
+** 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);
+}
+
+/*
+** 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;
+}
+
+/*
+** Print an entire page of content as hex
+*/
+static void print_oneline_frame(int iFrame){
+  int iStart;
+  unsigned char *aData;
+  iStart = 32 + (iFrame-1)*(pagesize+24);
+  aData = getContent(iStart, 24);
+  fprintf(stdout, "Frame %4d: %6d %6d 0x%08x 0x%08x 0x%08x 0x%08x\n",
+          iFrame, 
+          getInt32(aData),
+          getInt32(aData+4),
+          getInt32(aData+8),
+          getInt32(aData+12),
+          getInt32(aData+16),
+          getInt32(aData+20)
+  );
+  free(aData);
+}
+
+/*
+** Decode the WAL header.
+*/
+static void print_wal_header(void){
+  unsigned char *aData;
+  aData = getContent(0, 32);
+  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");
+  free(aData);
+}
+
+/*
+** Create a description for a single cell.
+*/
+static int describeCell(unsigned char cType, unsigned char *a, char **pzDesc){
+  int i;
+  int nDesc = 0;
+  int n = 0;
+  int leftChild;
+  i64 nPayload;
+  i64 rowid;
+  static char zDesc[100];
+  i = 0;
+  if( cType<=5 ){
+    leftChild = ((a[0]*256 + a[1])*256 + a[2])*256 + a[3];
+    a += 4;
+    n += 4;
+    sprintf(zDesc, "left-child: %d ", leftChild);
+    nDesc = strlen(zDesc);
+  }
+  if( cType!=5 ){
+    i = decodeVarint(a, &nPayload);
+    a += i;
+    n += i;
+    sprintf(&zDesc[nDesc], "sz: %lld ", nPayload);
+    nDesc += strlen(&zDesc[nDesc]);
+  }
+  if( cType==5 || cType==13 ){
+    i = decodeVarint(a, &rowid);
+    a += i;
+    n += i;
+    sprintf(&zDesc[nDesc], "rowid: %lld ", rowid);
+    nDesc += strlen(&zDesc[nDesc]);
+  }
+  *pzDesc = zDesc;
+  return n;
+}
+
+/*
+** Decode a btree page
+*/
+static void decode_btree_page(unsigned char *a, int pgno, int hdrSize){
+  const char *zType = "unknown";
+  int nCell;
+  int i;
+  int iCellPtr;
+  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;
+  }
+  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;
+  }
+  for(i=0; i<nCell; i++){
+    int cofst = iCellPtr + i*2;
+    char *zDesc;
+    cofst = a[cofst]*256 + a[cofst+1];
+    describeCell(a[0], &a[cofst-hdrSize], &zDesc);
+    printf(" %03x: cell[%d] %s\n", cofst, i, zDesc);
+  }
+}
+
+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;
+    print_wal_header();
+    for(i=1; i<=mxFrame; i++) print_oneline_frame(i);
+  }else{
+    int i;
+    for(i=2; i<argc; i++){
+      int iStart, iEnd;
+      char *zLeft;
+      if( strcmp(argv[i], "header")==0 ){
+        print_wal_header();
+        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);
+#if 0
+      }else if( zLeft && zLeft[0]=='b' ){
+        int ofst, nByte, hdrSize;
+        unsigned char *a;
+        if( iStart==1 ){
+          ofst = hdrSize = 100;
+          nByte = pagesize-100;
+        }else{
+          hdrSize = 0;
+          ofst = (iStart-1)*pagesize;
+          nByte = pagesize;
+        }
+        a = getContent(ofst, nByte);
+        decode_btree_page(a, iStart, hdrSize);
+        free(a);
+        continue;
+#endif
+      }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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