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/export.h>
  14
  15 const char hex_asc[] = "0123456789abcdef";
  16 EXPORT_SYMBOL(hex_asc);
  17 const char hex_asc_upper[] = "0123456789ABCDEF";
  18 EXPORT_SYMBOL(hex_asc_upper);
  19
  20 /**
  21  * hex_to_bin - convert a hex digit to its real value
  22  * @ch: ascii character represents hex digit
  23  *
  24  * hex_to_bin() converts one hex digit to its actual value or -1 in case of bad
  25  * input.
  26  */
  27 int hex_to_bin(char ch)
  28 {
  29         if ((ch >= '0') && (ch <= '9'))
  30                 return ch - '0';
  31         ch = tolower(ch);
  32         if ((ch >= 'a') && (ch <= 'f'))
  33                 return ch - 'a' + 10;
  34         return -1;
  35 }
  36 EXPORT_SYMBOL(hex_to_bin);
  37
  38 /**
  39  * hex2bin - convert an ascii hexadecimal string to its binary representation
  40  * @dst: binary result
  41  * @src: ascii hexadecimal string
  42  * @count: result length
  43  *
  44  * Return 0 on success, -1 in case of bad input.
  45  */
  46 int hex2bin(u8 *dst, const char *src, size_t count)
  47 {
  48         while (count--) {
  49                 int hi = hex_to_bin(*src++);
  50                 int lo = hex_to_bin(*src++);
  51
  52                 if ((hi < 0) || (lo < 0))
  53                         return -1;
  54
  55                 *dst++ = (hi << 4) | lo;
  56         }
  57         return 0;
  58 }
  59 EXPORT_SYMBOL(hex2bin);
  60
  61 /**
  62  * hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
  63  * @buf: data blob to dump
  64  * @len: number of bytes in the @buf
  65  * @rowsize: number of bytes to print per line; must be 16 or 32
  66  * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
  67  * @linebuf: where to put the converted data
  68  * @linebuflen: total size of @linebuf, including space for terminating NUL
  69  * @ascii: include ASCII after the hex output
  70  *
  71  * hex_dump_to_buffer() works on one "line" of output at a time, i.e.,
  72  * 16 or 32 bytes of input data converted to hex + ASCII output.
  73  *
  74  * Given a buffer of u8 data, hex_dump_to_buffer() converts the input data
  75  * to a hex + ASCII dump at the supplied memory location.
  76  * The converted output is always NUL-terminated.
  77  *
  78  * E.g.:
  79  *   hex_dump_to_buffer(frame->data, frame->len, 16, 1,
  80  *                      linebuf, sizeof(linebuf), true);
  81  *
  82  * example output buffer:
  83  * 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f  @ABCDEFGHIJKLMNO
  84  */
  85 void hex_dump_to_buffer(const void *buf, size_t len, int rowsize,
  86                         int groupsize, char *linebuf, size_t linebuflen,
  87                         bool ascii)
  88 {
  89         const u8 *ptr = buf;
  90         u8 ch;
  91         int j, lx = 0;
  92         int ascii_column;
  93
  94         if (rowsize != 16 && rowsize != 32)
  95                 rowsize = 16;
  96
  97         if (!len)
  98                 goto nil;
  99         if (len > rowsize)              /* limit to one line at a time */
 100                 len = rowsize;
 101         if ((len % groupsize) != 0)     /* no mixed size output */
 102                 groupsize = 1;
 103
 104         switch (groupsize) {
 105         case 8: {
 106                 const u64 *ptr8 = buf;
 107                 int ngroups = len / groupsize;
 108
 109                 for (j = 0; j < ngroups; j++)
 110                         lx += scnprintf(linebuf + lx, linebuflen - lx,
 111                                         "%s%16.16llx", j ? " " : "",
 112                                         (unsigned long long)*(ptr8 + j));
 113                 ascii_column = 17 * ngroups + 2;
 114                 break;
 115         }
 116
 117         case 4: {
 118                 const u32 *ptr4 = buf;
 119                 int ngroups = len / groupsize;
 120
 121                 for (j = 0; j < ngroups; j++)
 122                         lx += scnprintf(linebuf + lx, linebuflen - lx,
 123                                         "%s%8.8x", j ? " " : "", *(ptr4 + j));
 124                 ascii_column = 9 * ngroups + 2;
 125                 break;
 126         }
 127
 128         case 2: {
 129                 const u16 *ptr2 = buf;
 130                 int ngroups = len / groupsize;
 131
 132                 for (j = 0; j < ngroups; j++)
 133                         lx += scnprintf(linebuf + lx, linebuflen - lx,
 134                                         "%s%4.4x", j ? " " : "", *(ptr2 + j));
 135                 ascii_column = 5 * ngroups + 2;
 136                 break;
 137         }
 138
 139         default:
 140                 for (j = 0; (j < len) && (lx + 3) <= linebuflen; j++) {
 141                         ch = ptr[j];
 142                         linebuf[lx++] = hex_asc_hi(ch);
 143                         linebuf[lx++] = hex_asc_lo(ch);
 144                         linebuf[lx++] = ' ';
 145                 }
 146                 if (j)
 147                         lx--;
 148
 149                 ascii_column = 3 * rowsize + 2;
 150                 break;
 151         }
 152         if (!ascii)
 153                 goto nil;
 154
 155         while (lx < (linebuflen - 1) && lx < (ascii_column - 1))
 156                 linebuf[lx++] = ' ';
 157         for (j = 0; (j < len) && (lx + 2) < linebuflen; j++) {
 158                 ch = ptr[j];
 159                 linebuf[lx++] = (isascii(ch) && isprint(ch)) ? ch : '.';
 160         }
 161 nil:
 162         linebuf[lx++] = '\0';
 163 }
 164 EXPORT_SYMBOL(hex_dump_to_buffer);
 165
 166 #ifdef CONFIG_PRINTK
 167 /**
 168  * print_hex_dump - print a text hex dump to syslog for a binary blob of data
 169  * @level: kernel log level (e.g. KERN_DEBUG)
 170  * @prefix_str: string to prefix each line with;
 171  *  caller supplies trailing spaces for alignment if desired
 172  * @prefix_type: controls whether prefix of an offset, address, or none
 173  *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
 174  * @rowsize: number of bytes to print per line; must be 16 or 32
 175  * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
 176  * @buf: data blob to dump
 177  * @len: number of bytes in the @buf
 178  * @ascii: include ASCII after the hex output
 179  *
 180  * Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump
 181  * to the kernel log at the specified kernel log level, with an optional
 182  * leading prefix.
 183  *
 184  * print_hex_dump() works on one "line" of output at a time, i.e.,
 185  * 16 or 32 bytes of input data converted to hex + ASCII output.
 186  * print_hex_dump() iterates over the entire input @buf, breaking it into
 187  * "line size" chunks to format and print.
 188  *
 189  * E.g.:
 190  *   print_hex_dump(KERN_DEBUG, "raw data: ", DUMP_PREFIX_ADDRESS,
 191  *                  16, 1, frame->data, frame->len, true);
 192  *
 193  * Example output using %DUMP_PREFIX_OFFSET and 1-byte mode:
 194  * 0009ab42: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f  @ABCDEFGHIJKLMNO
 195  * Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode:
 196  * ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c  pqrstuvwxyz{|}~.
 197  */
 198 void print_hex_dump(const char *level, const char *prefix_str, int prefix_type,
 199                     int rowsize, int groupsize,
 200                     const void *buf, size_t len, bool ascii)
 201 {
 202         const u8 *ptr = buf;
 203         int i, linelen, remaining = len;
 204         unsigned char linebuf[32 * 3 + 2 + 32 + 1];
 205
 206         if (rowsize != 16 && rowsize != 32)
 207                 rowsize = 16;
 208
 209         for (i = 0; i < len; i += rowsize) {
 210                 linelen = min(remaining, rowsize);
 211                 remaining -= rowsize;
 212
 213                 hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
 214                                    linebuf, sizeof(linebuf), ascii);
 215
 216                 switch (prefix_type) {
 217                 case DUMP_PREFIX_ADDRESS:
 218                         printk("%s%s%p: %s\n",
 219                                level, prefix_str, ptr + i, linebuf);
 220                         break;
 221                 case DUMP_PREFIX_OFFSET:
 222                         printk("%s%s%.8x: %s\n", level, prefix_str, i, linebuf);
 223                         break;
 224                 default:
 225                         printk("%s%s%s\n", level, prefix_str, linebuf);
 226                         break;
 227                 }
 228         }
 229 }
 230 EXPORT_SYMBOL(print_hex_dump);
 231
 232 #if !defined(CONFIG_DYNAMIC_DEBUG)
 233 /**
 234  * print_hex_dump_bytes - shorthand form of print_hex_dump() with default params
 235  * @prefix_str: string to prefix each line with;
 236  *  caller supplies trailing spaces for alignment if desired
 237  * @prefix_type: controls whether prefix of an offset, address, or none
 238  *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
 239  * @buf: data blob to dump
 240  * @len: number of bytes in the @buf
 241  *
 242  * Calls print_hex_dump(), with log level of KERN_DEBUG,
 243  * rowsize of 16, groupsize of 1, and ASCII output included.
 244  */
 245 void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
 246                           const void *buf, size_t len)
 247 {
 248         print_hex_dump(KERN_DEBUG, prefix_str, prefix_type, 16, 1,
 249                        buf, len, true);
 250 }
 251 EXPORT_SYMBOL(print_hex_dump_bytes);
 252 #endif /* !defined(CONFIG_DYNAMIC_DEBUG) */
 253 #endif /* defined(CONFIG_PRINTK) */