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  * 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  */
  60 void 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         }
 136 nil:
 137         linebuf[lx++] = '\0';
 138 }
 139 EXPORT_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  */
 172 void 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 }
 204 EXPORT_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  */
 218 void 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 }
 224 EXPORT_SYMBOL(print_hex_dump_bytes);