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