Logo Search packages:      
Sourcecode: jfsutils version File versions  Download package

alter.c

/*
 *   Copyright (c) International Business Machines Corp., 2000-2002
 *
 *   This program is free software;  you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
 *   the GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program;  if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
#include <config.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

#include "xpeek.h"
#include "devices.h"
#include "utilsubs.h"

void alter()
{
      int64_t address;
      int64_t block;
      uint8_t *buffer;
      uint8_t byte;
      char cmdline[512];
      char *hexstring;
      unsigned hex_length;
      unsigned length;
      unsigned offset;
      char *ptr;
      char *token;

      token = strtok(0, "     \n");
      if (token == 0) {
            fputs("alter: Please enter: block offset hex-digits> ", stdout);
            fgets(cmdline, 512, stdin);
            token = strtok(cmdline, "     \n");
            if (token == 0)
                  return;
      }
      errno = 0;
      block = strtoull(token, 0, 0);
      if (block == 0 && errno) {
            fputs("alter: invalid block\n\n", stderr);
            return;
      }
      address = block << l2bsize;

      token = strtok(0, "     \n");
      if (!token) {
            fputs("alter:  Not enought arguments!\n", stderr);
            return;
      }
      offset = strtoul(token, 0, 16);
      if (offset == 0 && errno) {
            fputs("alter: invalid offset\n", stderr);
            return;
      }
      hexstring = strtok(0, "       \n");
      if (!hexstring) {
            fputs("alter: Not enough arguments!\n", stderr);
            return;
      }
      if (strtok(0, "   \n")) {
            fputs("alter: Too many arguments!\n", stderr);
            return;
      }
      hex_length = strlen(hexstring);
      if (hex_length & 1) {
            /* odd number of hex digits */
            fputs("alter: hex string must have even number of digits!\n", stderr);
            return;
      }

      /* Round length of data up to next full physical block */

      length = (offset + hex_length + bsize - 1) & ~(bsize - 1);

      buffer = (char *) malloc(length);
      if (!buffer) {
            fputs("alter: malloc failure!\n", stderr);
            return;
      }
      if (ujfs_rw_diskblocks(fp, address, length, buffer, GET)) {
            fputs("alter: failed reading disk data!\n", stderr);
            free(buffer);
            return;
      }
      for (ptr = hexstring; *ptr; ptr++) {
            if (*ptr >= '0' && *ptr <= '9')
                  byte = *ptr - '0';
            else if (*ptr >= 'a' && *ptr <= 'f')
                  byte = *ptr - 'a' + 10;
            else if (*ptr >= 'A' && *ptr <= 'F')
                  byte = *ptr - 'A' + 10;
            else {
                  fputs("alter: invalid hex digit!\n", stderr);
                  free(buffer);
                  return;
            }

            ptr++;
            byte <<= 4;

            if (*ptr >= '0' && *ptr <= '9')
                  byte += *ptr - '0';
            else if (*ptr >= 'a' && *ptr <= 'f')
                  byte += *ptr - 'a' + 10;
            else if (*ptr >= 'A' && *ptr <= 'F')
                  byte += *ptr - 'A' + 10;
            else {
                  fputs("alter: invalid hex digit!\n", stderr);
                  free(buffer);
                  return;
            }

            buffer[offset++] = byte;
      }
      if (ujfs_rw_diskblocks(fp, address, length, buffer, PUT))
            fputs("alter: failed writing disk data!\n", stderr);

      free(buffer);
      return;
}

Generated by  Doxygen 1.6.0   Back to index