debugfs/zap.c

   1 /*
   2  * zap.c --- zap block
   3  *
   4  * Copyright (C) 2012 Theodore Ts'o.  This file may be redistributed
   5  * under the terms of the GNU Public License.
   6  */
   7
   8 #include "config.h"
   9 #include <stdio.h>
  10 #include <unistd.h>
  11 #include <stdlib.h>
  12 #include <ctype.h>
  13 #include <string.h>
  14 #include <time.h>
  15 #ifdef HAVE_ERRNO_H
  16 #include <errno.h>
  17 #endif
  18 #include <sys/types.h>
  19 #ifdef HAVE_GETOPT_H
  20 #include <getopt.h>
  21 #else
  22 extern int optind;
  23 extern char *optarg;
  24 #endif
  25
  26 #include "debugfs.h"
  27
  28 void do_zap_block(int argc, char *argv[], int sci_idx EXT2FS_ATTR((unused)),
  29                     void *infop EXT2FS_ATTR((unused)))
  30 {
  31         unsigned long   pattern = 0;
  32         unsigned char   *buf;
  33         ext2_ino_t      inode;
  34         errcode_t       errcode;
  35         blk64_t         block;
  36         char            *file = NULL;
  37         int             c, err;
  38         int             offset = -1;
  39         int             length = -1;
  40         int             bit = -1;
  41
  42         if (check_fs_open(argv[0]))
  43                 return;
  44         if (check_fs_read_write(argv[0]))
  45                 return;
  46
  47         reset_getopt();
  48         while ((c = getopt (argc, argv, "b:f:l:o:p:")) != EOF) {
  49                 switch (c) {
  50                 case 'f':
  51                         file = optarg;
  52                         break;
  53                 case 'b':
  54                         bit = parse_ulong(optarg, argv[0],
  55                                           "bit", &err);
  56                         if (err)
  57                                 return;
  58                         if (bit >= (int) current_fs->blocksize * 8) {
  59                                 com_err(argv[0], 0, "The bit to flip "
  60                                         "must be within a %d block\n",
  61                                         current_fs->blocksize);
  62                                 return;
  63                         }
  64                         break;
  65                 case 'p':
  66                         pattern = parse_ulong(optarg, argv[0],
  67                                               "pattern", &err);
  68                         if (err)
  69                                 return;
  70                         if (pattern >= 256) {
  71                                 com_err(argv[0], 0, "The fill pattern must "
  72                                         "be an 8-bit value\n");
  73                                 return;
  74                         }
  75                         break;
  76                 case 'o':
  77                         offset = parse_ulong(optarg, argv[0],
  78                                              "offset", &err);
  79                         if (err)
  80                                 return;
  81                         if (offset >= (int) current_fs->blocksize) {
  82                                 com_err(argv[0], 0, "The offset must be "
  83                                         "within a %d block\n",
  84                                         current_fs->blocksize);
  85                                 return;
  86                         }
  87                         break;
  88
  89                         break;
  90                 case 'l':
  91                         length = parse_ulong(optarg, argv[0],
  92                                              "length", &err);
  93                         if (err)
  94                                 return;
  95                         break;
  96                 default:
  97                         goto print_usage;
  98                 }
  99         }
 100
 101         if (bit > 0 && offset > 0) {
 102                 com_err(argv[0], 0, "The -o and -b options can not be mixed.");
 103                 return;
 104         }
 105
 106         if (offset < 0)
 107                 offset = 0;
 108         if (length < 0)
 109                 length = current_fs->blocksize - offset;
 110         if ((offset + length) > (int) current_fs->blocksize) {
 111                 com_err(argv[0], 0, "The specified length is too bug\n");
 112                 return;
 113         }
 114
 115         if (argc != optind+1) {
 116         print_usage:
 117                 com_err(0, 0, "Usage:\tzap_block [-f file] [-o offset] "
 118                         "[-l length] [-p pattern] block_num");
 119                 com_err(0, 0, "\tzap_block [-f file] [-b bit] "
 120                         "block_num");
 121                 return;
 122         }
 123
 124         block = parse_ulonglong(argv[optind], argv[0], "block", &err);
 125         if (err)
 126                 return;
 127
 128         if (file) {
 129                 inode = string_to_inode(file);
 130                 if (!inode)
 131                         return;
 132                 errcode = ext2fs_bmap2(current_fs, inode, 0, 0, 0,
 133                                        block, 0, &block);
 134                 if (errcode) {
 135                         com_err(argv[0], errcode,
 136                                 "while mapping logical block %llu\n", block);
 137                         return;
 138                 }
 139         }
 140
 141         buf = malloc(current_fs->blocksize);
 142         if (!buf) {
 143                 com_err(argv[0], 0, "Couldn't allocate block buffer");
 144                 return;
 145         }
 146
 147         errcode = io_channel_read_blk64(current_fs->io, block, 1, buf);
 148         if (errcode) {
 149                 com_err(argv[0], errcode,
 150                         "while reading block %llu\n", block);
 151                 goto errout;
 152         }
 153
 154         if (bit >= 0)
 155                 buf[bit >> 3] ^= 1 << (bit & 7);
 156         else
 157                 memset(buf+offset, pattern, length);
 158
 159         errcode = io_channel_write_blk64(current_fs->io, block, 1, buf);
 160         if (errcode) {
 161                 com_err(argv[0], errcode,
 162                         "while write block %llu\n", block);
 163                 goto errout;
 164         }
 165
 166 errout:
 167         free(buf);
 168         return;
 169 }
 170
 171 void do_block_dump(int argc, char *argv[], int sci_idx EXT2FS_ATTR((unused)),
 172                     void *infop EXT2FS_ATTR((unused)))
 173 {
 174         unsigned char   *buf;
 175         ext2_ino_t      inode;
 176         errcode_t       errcode;
 177         blk64_t         block;
 178         char            *file = NULL;
 179         int             xattr_dump = 0;
 180         int             c, err;
 181
 182         if (check_fs_open(argv[0]))
 183                 return;
 184
 185         reset_getopt();
 186         while ((c = getopt (argc, argv, "f:x")) != EOF) {
 187                 switch (c) {
 188                 case 'f':
 189                         file = optarg;
 190                         break;
 191                 case 'x':
 192                         xattr_dump = 1;
 193                         break;
 194                 default:
 195                         goto print_usage;
 196                 }
 197         }
 198
 199         if (argc != optind + 1) {
 200         print_usage:
 201                 com_err(0, 0, "Usage: block_dump [-x] [-f inode] block_num");
 202                 return;
 203         }
 204
 205         block = parse_ulonglong(argv[optind], argv[0], "block", &err);
 206         if (err)
 207                 return;
 208
 209         if (file) {
 210                 inode = string_to_inode(file);
 211                 if (!inode)
 212                         return;
 213                 errcode = ext2fs_bmap2(current_fs, inode, 0, 0, 0,
 214                                        block, 0, &block);
 215                 if (errcode) {
 216                         com_err(argv[0], errcode,
 217                                 "while mapping logical block %llu\n", block);
 218                         return;
 219                 }
 220         }
 221
 222         buf = malloc(current_fs->blocksize);
 223         if (!buf) {
 224                 com_err(argv[0], 0, "Couldn't allocate block buffer");
 225                 return;
 226         }
 227
 228         errcode = io_channel_read_blk64(current_fs->io, block, 1, buf);
 229         if (errcode) {
 230                 com_err(argv[0], errcode,
 231                         "while reading block %llu\n", block);
 232                 goto errout;
 233         }
 234
 235         if (xattr_dump)
 236                 block_xattr_dump(stdout, buf, current_fs->blocksize);
 237         else
 238                 do_byte_hexdump(stdout, buf, current_fs->blocksize);
 239 errout:
 240         free(buf);
 241 }
 242
 243 void do_byte_hexdump(FILE *fp, unsigned char *buf, size_t bufsize)
 244 {
 245         size_t          i, j, max;
 246         int             suppress = -1;
 247
 248         for (i = 0; i < bufsize; i += 16) {
 249                 max = (bufsize - i > 16) ? 16 : bufsize - i;
 250                 if (suppress < 0) {
 251                         if (i && memcmp(buf + i, buf + i - max, max) == 0) {
 252                                 suppress = i;
 253                                 fprintf(fp, "*\n");
 254                                 continue;
 255                         }
 256                 } else {
 257                         if (memcmp(buf + i, buf + suppress, max) == 0)
 258                                 continue;
 259                         suppress = -1;
 260                 }
 261                 fprintf(fp, "%04o  ", (unsigned int)i);
 262                 for (j = 0; j < 16; j++) {
 263                         if (j < max)
 264                                 fprintf(fp, "%02x", buf[i+j]);
 265                         else
 266                                 fprintf(fp, "  ");
 267                         if ((j % 2) == 1)
 268                                 fprintf(fp, " ");
 269                 }
 270                 fprintf(fp, " ");
 271                 for (j = 0; j < max; j++)
 272                         fprintf(fp, "%c", isprint(buf[i+j]) ? buf[i+j] : '.');
 273                 fprintf(fp, "\n");
 274         }
 275         fprintf(fp, "\n");
 276 }