lib/hexdump.c

   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
  15 const char hex_asc[] = "0123456789abcdef";
  16 EXPORT_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  */
  25 int 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 }
  34 EXPORT_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 void 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 }
  50 EXPORT_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  */
  76 void 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         }
 152 nil:
 153         linebuf[lx++] = '\0';
 154 }
 155 EXPORT_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  */
 189 void 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 }
 221 EXPORT_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  */
 235 void 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 }
 241 EXPORT_SYMBOL(print_hex_dump_bytes);
 242 #endif