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  * Return 0 on success, -1 in case of bad input.
  43  */
  44 int 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 }
  57 EXPORT_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  */
  83 void 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         }
 159 nil:
 160         linebuf[lx++] = '\0';
 161 }
 162 EXPORT_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  */
 196 void 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 }
 228 EXPORT_SYMBOL(print_hex_dump);
 229
 230 /**
 231  * print_hex_dump_bytes - shorthand form of print_hex_dump() with default params
 232  * @prefix_str: string to prefix each line with;
 233  *  caller supplies trailing spaces for alignment if desired
 234  * @prefix_type: controls whether prefix of an offset, address, or none
 235  *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
 236  * @buf: data blob to dump
 237  * @len: number of bytes in the @buf
 238  *
 239  * Calls print_hex_dump(), with log level of KERN_DEBUG,
 240  * rowsize of 16, groupsize of 1, and ASCII output included.
 241  */
 242 void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
 243                           const void *buf, size_t len)
 244 {
 245         print_hex_dump(KERN_DEBUG, prefix_str, prefix_type, 16, 1,
 246                        buf, len, true);
 247 }
 248 EXPORT_SYMBOL(print_hex_dump_bytes);
 249 #endif