linux/lib/hexdump.c
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   1/*
   2 * lib/hexdump.c
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License version 2 as
   6 * published by the Free Software Foundation. See README and COPYING for
   7 * more details.
   8 */
   9
  10#include <linux/types.h>
  11#include <linux/ctype.h>
  12#include <linux/kernel.h>
  13#include <linux/module.h>
  14
  15const char hex_asc[] = "0123456789abcdef";
  16EXPORT_SYMBOL(hex_asc);
  17
  18/**
  19 * hex_to_bin - convert a hex digit to its real value
  20 * @ch: ascii character represents hex digit
  21 *
  22 * hex_to_bin() converts one hex digit to its actual value or -1 in case of bad
  23 * input.
  24 */
  25int hex_to_bin(char ch)
  26{
  27        if ((ch >= '0') && (ch <= '9'))
  28                return ch - '0';
  29        ch = tolower(ch);
  30        if ((ch >= 'a') && (ch <= 'f'))
  31                return ch - 'a' + 10;
  32        return -1;
  33}
  34EXPORT_SYMBOL(hex_to_bin);
  35
  36/**
  37 * hex2bin - convert an ascii hexadecimal string to its binary representation
  38 * @dst: binary result
  39 * @src: ascii hexadecimal string
  40 * @count: result length
  41 */
  42void hex2bin(u8 *dst, const char *src, size_t count)
  43{
  44        while (count--) {
  45                *dst = hex_to_bin(*src++) << 4;
  46                *dst += hex_to_bin(*src++);
  47                dst++;
  48        }
  49}
  50EXPORT_SYMBOL(hex2bin);
  51
  52/**
  53 * hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
  54 * @buf: data blob to dump
  55 * @len: number of bytes in the @buf
  56 * @rowsize: number of bytes to print per line; must be 16 or 32
  57 * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
  58 * @linebuf: where to put the converted data
  59 * @linebuflen: total size of @linebuf, including space for terminating NUL
  60 * @ascii: include ASCII after the hex output
  61 *
  62 * hex_dump_to_buffer() works on one "line" of output at a time, i.e.,
  63 * 16 or 32 bytes of input data converted to hex + ASCII output.
  64 *
  65 * Given a buffer of u8 data, hex_dump_to_buffer() converts the input data
  66 * to a hex + ASCII dump at the supplied memory location.
  67 * The converted output is always NUL-terminated.
  68 *
  69 * E.g.:
  70 *   hex_dump_to_buffer(frame->data, frame->len, 16, 1,
  71 *                      linebuf, sizeof(linebuf), true);
  72 *
  73 * example output buffer:
  74 * 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f  @ABCDEFGHIJKLMNO
  75 */
  76void hex_dump_to_buffer(const void *buf, size_t len, int rowsize,
  77                        int groupsize, char *linebuf, size_t linebuflen,
  78                        bool ascii)
  79{
  80        const u8 *ptr = buf;
  81        u8 ch;
  82        int j, lx = 0;
  83        int ascii_column;
  84
  85        if (rowsize != 16 && rowsize != 32)
  86                rowsize = 16;
  87
  88        if (!len)
  89                goto nil;
  90        if (len > rowsize)              /* limit to one line at a time */
  91                len = rowsize;
  92        if ((len % groupsize) != 0)     /* no mixed size output */
  93                groupsize = 1;
  94
  95        switch (groupsize) {
  96        case 8: {
  97                const u64 *ptr8 = buf;
  98                int ngroups = len / groupsize;
  99
 100                for (j = 0; j < ngroups; j++)
 101                        lx += scnprintf(linebuf + lx, linebuflen - lx,
 102                                        "%s%16.16llx", j ? " " : "",
 103                                        (unsigned long long)*(ptr8 + j));
 104                ascii_column = 17 * ngroups + 2;
 105                break;
 106        }
 107
 108        case 4: {
 109                const u32 *ptr4 = buf;
 110                int ngroups = len / groupsize;
 111
 112                for (j = 0; j < ngroups; j++)
 113                        lx += scnprintf(linebuf + lx, linebuflen - lx,
 114                                        "%s%8.8x", j ? " " : "", *(ptr4 + j));
 115                ascii_column = 9 * ngroups + 2;
 116                break;
 117        }
 118
 119        case 2: {
 120                const u16 *ptr2 = buf;
 121                int ngroups = len / groupsize;
 122
 123                for (j = 0; j < ngroups; j++)
 124                        lx += scnprintf(linebuf + lx, linebuflen - lx,
 125                                        "%s%4.4x", j ? " " : "", *(ptr2 + j));
 126                ascii_column = 5 * ngroups + 2;
 127                break;
 128        }
 129
 130        default:
 131                for (j = 0; (j < len) && (lx + 3) <= linebuflen; j++) {
 132                        ch = ptr[j];
 133                        linebuf[lx++] = hex_asc_hi(ch);
 134                        linebuf[lx++] = hex_asc_lo(ch);
 135                        linebuf[lx++] = ' ';
 136                }
 137                if (j)
 138                        lx--;
 139
 140                ascii_column = 3 * rowsize + 2;
 141                break;
 142        }
 143        if (!ascii)
 144                goto nil;
 145
 146        while (lx < (linebuflen - 1) && lx < (ascii_column - 1))
 147                linebuf[lx++] = ' ';
 148        for (j = 0; (j < len) && (lx + 2) < linebuflen; j++) {
 149                ch = ptr[j];
 150                linebuf[lx++] = (isascii(ch) && isprint(ch)) ? ch : '.';
 151        }
 152nil:
 153        linebuf[lx++] = '\0';
 154}
 155EXPORT_SYMBOL(hex_dump_to_buffer);
 156
 157#ifdef CONFIG_PRINTK
 158/**
 159 * print_hex_dump - print a text hex dump to syslog for a binary blob of data
 160 * @level: kernel log level (e.g. KERN_DEBUG)
 161 * @prefix_str: string to prefix each line with;
 162 *  caller supplies trailing spaces for alignment if desired
 163 * @prefix_type: controls whether prefix of an offset, address, or none
 164 *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
 165 * @rowsize: number of bytes to print per line; must be 16 or 32
 166 * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
 167 * @buf: data blob to dump
 168 * @len: number of bytes in the @buf
 169 * @ascii: include ASCII after the hex output
 170 *
 171 * Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump
 172 * to the kernel log at the specified kernel log level, with an optional
 173 * leading prefix.
 174 *
 175 * print_hex_dump() works on one "line" of output at a time, i.e.,
 176 * 16 or 32 bytes of input data converted to hex + ASCII output.
 177 * print_hex_dump() iterates over the entire input @buf, breaking it into
 178 * "line size" chunks to format and print.
 179 *
 180 * E.g.:
 181 *   print_hex_dump(KERN_DEBUG, "raw data: ", DUMP_PREFIX_ADDRESS,
 182 *                  16, 1, frame->data, frame->len, true);
 183 *
 184 * Example output using %DUMP_PREFIX_OFFSET and 1-byte mode:
 185 * 0009ab42: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f  @ABCDEFGHIJKLMNO
 186 * Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode:
 187 * ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c  pqrstuvwxyz{|}~.
 188 */
 189void print_hex_dump(const char *level, const char *prefix_str, int prefix_type,
 190                    int rowsize, int groupsize,
 191                    const void *buf, size_t len, bool ascii)
 192{
 193        const u8 *ptr = buf;
 194        int i, linelen, remaining = len;
 195        unsigned char linebuf[32 * 3 + 2 + 32 + 1];
 196
 197        if (rowsize != 16 && rowsize != 32)
 198                rowsize = 16;
 199
 200        for (i = 0; i < len; i += rowsize) {
 201                linelen = min(remaining, rowsize);
 202                remaining -= rowsize;
 203
 204                hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
 205                                   linebuf, sizeof(linebuf), ascii);
 206
 207                switch (prefix_type) {
 208                case DUMP_PREFIX_ADDRESS:
 209                        printk("%s%s%p: %s\n",
 210                               level, prefix_str, ptr + i, linebuf);
 211                        break;
 212                case DUMP_PREFIX_OFFSET:
 213                        printk("%s%s%.8x: %s\n", level, prefix_str, i, linebuf);
 214                        break;
 215                default:
 216                        printk("%s%s%s\n", level, prefix_str, linebuf);
 217                        break;
 218                }
 219        }
 220}
 221EXPORT_SYMBOL(print_hex_dump);
 222
 223/**
 224 * print_hex_dump_bytes - shorthand form of print_hex_dump() with default params
 225 * @prefix_str: string to prefix each line with;
 226 *  caller supplies trailing spaces for alignment if desired
 227 * @prefix_type: controls whether prefix of an offset, address, or none
 228 *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
 229 * @buf: data blob to dump
 230 * @len: number of bytes in the @buf
 231 *
 232 * Calls print_hex_dump(), with log level of KERN_DEBUG,
 233 * rowsize of 16, groupsize of 1, and ASCII output included.
 234 */
 235void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
 236                          const void *buf, size_t len)
 237{
 238        print_hex_dump(KERN_DEBUG, prefix_str, prefix_type, 16, 1,
 239                       buf, len, true);
 240}
 241EXPORT_SYMBOL(print_hex_dump_bytes);
 242#endif
 243
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