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/export.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 *
  42 * Return 0 on success, -1 in case of bad input.
  43 */
  44int hex2bin(u8 *dst, const char *src, size_t count)
  45{
  46        while (count--) {
  47                int hi = hex_to_bin(*src++);
  48                int lo = hex_to_bin(*src++);
  49
  50                if ((hi < 0) || (lo < 0))
  51                        return -1;
  52
  53                *dst++ = (hi << 4) | lo;
  54        }
  55        return 0;
  56}
  57EXPORT_SYMBOL(hex2bin);
  58
  59/**
  60 * hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
  61 * @buf: data blob to dump
  62 * @len: number of bytes in the @buf
  63 * @rowsize: number of bytes to print per line; must be 16 or 32
  64 * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
  65 * @linebuf: where to put the converted data
  66 * @linebuflen: total size of @linebuf, including space for terminating NUL
  67 * @ascii: include ASCII after the hex output
  68 *
  69 * hex_dump_to_buffer() works on one "line" of output at a time, i.e.,
  70 * 16 or 32 bytes of input data converted to hex + ASCII output.
  71 *
  72 * Given a buffer of u8 data, hex_dump_to_buffer() converts the input data
  73 * to a hex + ASCII dump at the supplied memory location.
  74 * The converted output is always NUL-terminated.
  75 *
  76 * E.g.:
  77 *   hex_dump_to_buffer(frame->data, frame->len, 16, 1,
  78 *                      linebuf, sizeof(linebuf), true);
  79 *
  80 * example output buffer:
  81 * 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f  @ABCDEFGHIJKLMNO
  82 */
  83void hex_dump_to_buffer(const void *buf, size_t len, int rowsize,
  84                        int groupsize, char *linebuf, size_t linebuflen,
  85                        bool ascii)
  86{
  87        const u8 *ptr = buf;
  88        u8 ch;
  89        int j, lx = 0;
  90        int ascii_column;
  91
  92        if (rowsize != 16 && rowsize != 32)
  93                rowsize = 16;
  94
  95        if (!len)
  96                goto nil;
  97        if (len > rowsize)              /* limit to one line at a time */
  98                len = rowsize;
  99        if ((len % groupsize) != 0)     /* no mixed size output */
 100                groupsize = 1;
 101
 102        switch (groupsize) {
 103        case 8: {
 104                const u64 *ptr8 = buf;
 105                int ngroups = len / groupsize;
 106
 107                for (j = 0; j < ngroups; j++)
 108                        lx += scnprintf(linebuf + lx, linebuflen - lx,
 109                                        "%s%16.16llx", j ? " " : "",
 110                                        (unsigned long long)*(ptr8 + j));
 111                ascii_column = 17 * ngroups + 2;
 112                break;
 113        }
 114
 115        case 4: {
 116                const u32 *ptr4 = buf;
 117                int ngroups = len / groupsize;
 118
 119                for (j = 0; j < ngroups; j++)
 120                        lx += scnprintf(linebuf + lx, linebuflen - lx,
 121                                        "%s%8.8x", j ? " " : "", *(ptr4 + j));
 122                ascii_column = 9 * ngroups + 2;
 123                break;
 124        }
 125
 126        case 2: {
 127                const u16 *ptr2 = buf;
 128                int ngroups = len / groupsize;
 129
 130                for (j = 0; j < ngroups; j++)
 131                        lx += scnprintf(linebuf + lx, linebuflen - lx,
 132                                        "%s%4.4x", j ? " " : "", *(ptr2 + j));
 133                ascii_column = 5 * ngroups + 2;
 134                break;
 135        }
 136
 137        default:
 138                for (j = 0; (j < len) && (lx + 3) <= linebuflen; j++) {
 139                        ch = ptr[j];
 140                        linebuf[lx++] = hex_asc_hi(ch);
 141                        linebuf[lx++] = hex_asc_lo(ch);
 142                        linebuf[lx++] = ' ';
 143                }
 144                if (j)
 145                        lx--;
 146
 147                ascii_column = 3 * rowsize + 2;
 148                break;
 149        }
 150        if (!ascii)
 151                goto nil;
 152
 153        while (lx < (linebuflen - 1) && lx < (ascii_column - 1))
 154                linebuf[lx++] = ' ';
 155        for (j = 0; (j < len) && (lx + 2) < linebuflen; j++) {
 156                ch = ptr[j];
 157                linebuf[lx++] = (isascii(ch) && isprint(ch)) ? ch : '.';
 158        }
 159nil:
 160        linebuf[lx++] = '\0';
 161}
 162EXPORT_SYMBOL(hex_dump_to_buffer);
 163
 164#ifdef CONFIG_PRINTK
 165/**
 166 * print_hex_dump - print a text hex dump to syslog for a binary blob of data
 167 * @level: kernel log level (e.g. KERN_DEBUG)
 168 * @prefix_str: string to prefix each line with;
 169 *  caller supplies trailing spaces for alignment if desired
 170 * @prefix_type: controls whether prefix of an offset, address, or none
 171 *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
 172 * @rowsize: number of bytes to print per line; must be 16 or 32
 173 * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
 174 * @buf: data blob to dump
 175 * @len: number of bytes in the @buf
 176 * @ascii: include ASCII after the hex output
 177 *
 178 * Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump
 179 * to the kernel log at the specified kernel log level, with an optional
 180 * leading prefix.
 181 *
 182 * print_hex_dump() works on one "line" of output at a time, i.e.,
 183 * 16 or 32 bytes of input data converted to hex + ASCII output.
 184 * print_hex_dump() iterates over the entire input @buf, breaking it into
 185 * "line size" chunks to format and print.
 186 *
 187 * E.g.:
 188 *   print_hex_dump(KERN_DEBUG, "raw data: ", DUMP_PREFIX_ADDRESS,
 189 *                  16, 1, frame->data, frame->len, true);
 190 *
 191 * Example output using %DUMP_PREFIX_OFFSET and 1-byte mode:
 192 * 0009ab42: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f  @ABCDEFGHIJKLMNO
 193 * Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode:
 194 * ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c  pqrstuvwxyz{|}~.
 195 */
 196void print_hex_dump(const char *level, const char *prefix_str, int prefix_type,
 197                    int rowsize, int groupsize,
 198                    const void *buf, size_t len, bool ascii)
 199{
 200        const u8 *ptr = buf;
 201        int i, linelen, remaining = len;
 202        unsigned char linebuf[32 * 3 + 2 + 32 + 1];
 203
 204        if (rowsize != 16 && rowsize != 32)
 205                rowsize = 16;
 206
 207        for (i = 0; i < len; i += rowsize) {
 208                linelen = min(remaining, rowsize);
 209                remaining -= rowsize;
 210
 211                hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
 212                                   linebuf, sizeof(linebuf), ascii);
 213
 214                switch (prefix_type) {
 215                case DUMP_PREFIX_ADDRESS:
 216                        printk("%s%s%p: %s\n",
 217                               level, prefix_str, ptr + i, linebuf);
 218                        break;
 219                case DUMP_PREFIX_OFFSET:
 220                        printk("%s%s%.8x: %s\n", level, prefix_str, i, linebuf);
 221                        break;
 222                default:
 223                        printk("%s%s%s\n", level, prefix_str, linebuf);
 224                        break;
 225                }
 226        }
 227}
 228EXPORT_SYMBOL(print_hex_dump);
 229
 230#if !defined(CONFIG_DYNAMIC_DEBUG)
 231/**
 232 * print_hex_dump_bytes - shorthand form of print_hex_dump() with default params
 233 * @prefix_str: string to prefix each line with;
 234 *  caller supplies trailing spaces for alignment if desired
 235 * @prefix_type: controls whether prefix of an offset, address, or none
 236 *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
 237 * @buf: data blob to dump
 238 * @len: number of bytes in the @buf
 239 *
 240 * Calls print_hex_dump(), with log level of KERN_DEBUG,
 241 * rowsize of 16, groupsize of 1, and ASCII output included.
 242 */
 243void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
 244                          const void *buf, size_t len)
 245{
 246        print_hex_dump(KERN_DEBUG, prefix_str, prefix_type, 16, 1,
 247                       buf, len, true);
 248}
 249EXPORT_SYMBOL(print_hex_dump_bytes);
 250#endif /* !defined(CONFIG_DYNAMIC_DEBUG) */
 251#endif /* defined(CONFIG_PRINTK) */
 252
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