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htree.c

/*
 * htree.c --- hash tree routines
 * 
 * Copyright (C) 2002 Theodore Ts'o.  This file may be redistributed
 * under the terms of the GNU Public License.
 */

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <time.h>
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#include <sys/types.h>
#ifdef HAVE_GETOPT_H
#include <getopt.h>
#else 
extern int optind;
extern char *optarg;
#endif
#ifdef HAVE_OPTRESET
extern int optreset;          /* defined by BSD, but not others */
#endif

#include "debugfs.h"

static FILE *pager;

static unsigned dx_hack_hash (const char *name, int len)
{
      __u32 hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
      while (len--) {
            __u32 hash = hash1 + (hash0 ^ (*name++ * 7152373));
            
            if (hash & 0x80000000) hash -= 0x7fffffff;
            hash1 = hash0;
            hash0 = hash;
      }
      return hash0;
}

#define dx_hash(s,n) (dx_hack_hash(s,n) << 1)

static void htree_dump_leaf_node(ext2_filsys fs, ext2_ino_t ino,
                         struct ext2_inode *inode,
                         blk_t blk, char *buf)
{
      errcode_t   errcode;
      struct ext2_dir_entry *dirent;
      int         thislen, col = 0, offset = 0;
      char        name[EXT2_NAME_LEN];
      char        tmp[EXT2_NAME_LEN + 16];
      blk_t       pblk;
      
      errcode = ext2fs_bmap(fs, ino, inode, buf, 0, blk, &pblk);
      if (errcode) {
            com_err("htree_dump_leaf_node", errcode,
                  "while mapping logical block %d\n", blk);
            return;
      }

      errcode = io_channel_read_blk(current_fs->io, pblk, 1, buf);
      if (errcode) {
            com_err("htree_dump_leaf_node", errcode,
                  "while      reading block %d\n", blk);
            return;
      }

      while (offset < fs->blocksize) {
            dirent = (struct ext2_dir_entry *) (buf + offset);
            if (((offset + dirent->rec_len) > fs->blocksize) ||
                (dirent->rec_len < 8) ||
                ((dirent->rec_len % 4) != 0) ||
                (((dirent->name_len & 0xFF)+8) > dirent->rec_len)) {
                  fprintf(pager, "Corrupted directory block (%d)!\n", blk);
                  break;
            }
            thislen = ((dirent->name_len & 0xFF) < EXT2_NAME_LEN) ?
                  (dirent->name_len & 0xFF) : EXT2_NAME_LEN;
            strncpy(name, dirent->name, thislen);
            name[thislen] = '\0';
            sprintf(tmp, "%u 0x%08x (%d) %s   ", dirent->inode,
                   dx_hash(name, thislen), dirent->rec_len, name);
            thislen = strlen(tmp);
            if (col + thislen > 80) {
                  fprintf(pager, "\n");
                  col = 0;
            }
            fprintf(pager, "%s", tmp);
            col += thislen;
            offset += dirent->rec_len;
      }
      fprintf(pager, "\n");
}


static void htree_dump_int_block(ext2_filsys fs, ext2_ino_t ino,
                         struct ext2_inode *inode,
                         blk_t blk, char *buf, int level);


static void htree_dump_int_node(ext2_filsys fs, ext2_ino_t ino,
                        struct ext2_inode *inode,
                        struct ext2_dx_entry *ent, 
                        char *buf, int level)
{
      struct            ext2_dx_countlimit *limit;
      int         i;

      limit = (struct ext2_dx_countlimit *) ent;

      fprintf(pager, "Number of entries (count): %d\n", limit->count);
      fprintf(pager, "Number of entries (limit): %d\n", limit->limit);

      for (i=0; i < limit->count; i++)
            fprintf(pager, "Entry #%d: Hash 0x%08x, block %d\n", i,
                   i ? ent[i].hash : 0, ent[i].block);

      fprintf(pager, "\n");

      for (i=0; i < limit->count; i++) {
            fprintf(pager, "Entry #%d: Hash 0x%08x, block %d\n", i,
                   i ? ent[i].hash : 0, ent[i].block);
            if (level)
                  htree_dump_int_block(fs, ino, inode,
                                   ent[i].block, buf, level-1);
            else
                  htree_dump_leaf_node(fs, ino, inode,
                                   ent[i].block, buf);
      }

      fprintf(pager, "---------------------\n");
}

static void htree_dump_int_block(ext2_filsys fs, ext2_ino_t ino,
                         struct ext2_inode *inode,
                         blk_t blk, char *buf, int level)
{
      char        *cbuf;
      errcode_t   errcode;
      blk_t       pblk;

      cbuf = malloc(fs->blocksize);
      if (!cbuf) {
            fprintf(pager, "Couldn't allocate child block.\n");
            return;
      }
      
      errcode = ext2fs_bmap(fs, ino, inode, buf, 0, blk, &pblk);
      if (errcode) {
            com_err("htree_dump_int_block", errcode,
                  "while mapping logical block %d\n", blk);
            return;
      }

      errcode = io_channel_read_blk(current_fs->io, pblk, 1, buf);
      if (errcode) {
            com_err("htree_dump_int_block", errcode,
                  "while      reading block %d\n", blk);
            return;
      }

      htree_dump_int_node(fs, ino, inode, (struct ext2_dx_entry *) (buf+8),
                      cbuf, level);
      free(cbuf);
}



void do_htree_dump(int argc, char *argv[])
{
      ext2_ino_t  ino;
      struct ext2_inode inode;
      int         retval;
      int         i, c;
      int         flags;
      int         long_opt;
      void        *buf = NULL;
      struct            ext2_dx_root_info  *root;
      struct            ext2_dx_entry *ent;
      struct            ext2_dx_countlimit *limit;
      errcode_t   errcode;

      if (check_fs_open(argv[0]))
            return;

      pager = open_pager();

      optind = 0;
#ifdef HAVE_OPTRESET
      optreset = 1;           /* Makes BSD getopt happy */
#endif
      while ((c = getopt (argc, argv, "l")) != EOF) {
            switch (c) {
            case 'l':
                  long_opt++;
                  break;
            }
      }

      if (argc > optind+1) {
            com_err(0, 0, "Usage: htree_dump [-l] file");
            return;
      }

      if (argc == optind)
            ino = cwd;
      else
            ino = string_to_inode(argv[optind]);
      if (!ino)
            return;

      if (debugfs_read_inode(ino, &inode, argv[1]))
            return;

      if (!LINUX_S_ISDIR(inode.i_mode)) {
            com_err(argv[0], 0, "Not a directory");
            return;
      }
      
      if ((inode.i_flags & EXT2_BTREE_FL) == 0) {
            com_err(argv[0], 0, "Not a hash-indexed directory");
            return;
      }

      buf = malloc(2*current_fs->blocksize);
      if (!buf) {
            com_err(argv[0], 0, "Couldn't allocate htree buffer");
            return;
      }

      errcode = io_channel_read_blk(current_fs->io, inode.i_block[0], 
                              1, buf);
      if (errcode) {
            com_err(argv[0], errcode, "Error reading root node");
            goto errout;
      }

      root = (struct ext2_dx_root_info *) (buf + 24);

      fprintf(pager, "Root node dump:\n");
      fprintf(pager, "\t Reserved zero: %d\n", root->reserved_zero);
      fprintf(pager, "\t Hash Version: %d\n", root->hash_version);
      fprintf(pager, "\t Info length: %d\n", root->info_length);
      fprintf(pager, "\t Indirect levels: %d\n", root->indirect_levels);
      fprintf(pager, "\t Flags: %d\n", root->unused_flags);

      ent = (struct ext2_dx_entry *) (buf + 24 + root->info_length);
      limit = (struct ext2_dx_countlimit *) ent;

      htree_dump_int_node(current_fs, ino, &inode, ent,
                      buf + current_fs->blocksize,
                      root->indirect_levels);

errout:
      if (buf)
            free(buf);
      close_pager(pager);
}

/*
 * This function prints the hash of a given file.
 */
void do_dx_hash(int argc, char *argv[])
{
      if (argc != 2) {
            com_err(argv[0], 0, "usage: dx_hash filename");
            return;
      }
      printf("Hash of %s is 0x%0x\n", argv[1],
             dx_hash(argv[1], strlen(argv[1])));
}

/*
 * Search for particular directory entry (useful for debugging very
 * large hash tree directories that have lost some blocks from the
 * btree index).
 */
struct process_block_struct {
      char  *search_name;
      char  *buf;
      int   len;
};

static int search_dir_block(ext2_filsys fs, blk_t *blocknr,
                      e2_blkcnt_t blockcnt, blk_t ref_blk, 
                      int ref_offset, void *priv_data);

void do_dirsearch(int argc, char *argv[])
{
      ext2_ino_t  inode;
      int         retval;
      int         c;
      int         flags;
      struct process_block_struct pb;
      
      if (check_fs_open(argv[0]))
            return;

      if (argc != 3) {
            com_err(0, 0, "Usage: dirsearch dir filename");
            return;
      }

      inode = string_to_inode(argv[1]);
      if (!inode)
            return;

      pb.buf = malloc(current_fs->blocksize);
      if (!pb.buf) {
            com_err("dirsearch", 0, "Couldn't allocate buffer");
            return;
      }
      pb.search_name = argv[2];
      pb.len = strlen(pb.search_name);
      
      ext2fs_block_iterate2(current_fs, inode, 0, 0, search_dir_block, &pb);

      free(pb.buf);
}


static int search_dir_block(ext2_filsys fs, blk_t *blocknr,
                      e2_blkcnt_t blockcnt, blk_t ref_blk, 
                      int ref_offset, void *priv_data)
{
      struct process_block_struct *p;
      struct ext2_dir_entry *dirent;
      errcode_t               errcode;
      int               offset = 0;

      if (blockcnt < 0)
            return 0;

      p = (struct process_block_struct *) priv_data;

      errcode = io_channel_read_blk(current_fs->io, *blocknr, 1, p->buf);
      if (errcode) {
            com_err("search_dir_block", errcode,
                  "while reading block %lu", *blocknr);
            return BLOCK_ABORT;
      }

      while (offset < fs->blocksize) {
            dirent = (struct ext2_dir_entry *) (p->buf + offset);

            if (dirent->inode &&
                p->len == (dirent->name_len & 0xFF) && 
                strncmp(p->search_name, dirent->name,
                      p->len) == 0) {
                  printf("Entry found at logical block %lld, "
                         "phys %d, offset %d\n", blockcnt,
                         *blocknr, offset);
                  printf("offset %d\n", offset);
                  return BLOCK_ABORT;
            }
            offset += dirent->rec_len;
      }
      return 0;
}


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