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