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                                 "%16.16llx ", (unsigned long long)*(ptr8 + j));
  69                 ascii_column = 17 * ngroups + 2;
  70                 break;
  71         }
  72
  73         case 4: {
  74                 const u32 *ptr4 = buf;
  75                 int ngroups = len / groupsize;
  76
  77                 for (j = 0; j < ngroups; j++)
  78                         lx += scnprintf(linebuf + lx, linebuflen - lx,
  79                                 "%8.8x ", *(ptr4 + j));
  80                 ascii_column = 9 * ngroups + 2;
  81                 break;
  82         }
  83
  84         case 2: {
  85                 const u16 *ptr2 = buf;
  86                 int ngroups = len / groupsize;
  87
  88                 for (j = 0; j < ngroups; j++)
  89                         lx += scnprintf(linebuf + lx, linebuflen - lx,
  90                                 "%4.4x ", *(ptr2 + j));
  91                 ascii_column = 5 * ngroups + 2;
  92                 break;
  93         }
  94
  95         default:
  96                 for (j = 0; (j < rowsize) && (j < len) && (lx + 4) < linebuflen;
  97                      j++) {
  98                         ch = ptr[j];
  99                         linebuf[lx++] = hex_asc_hi(ch);
 100                         linebuf[lx++] = hex_asc_lo(ch);
 101                         linebuf[lx++] = ' ';
 102                 }
 103                 ascii_column = 3 * rowsize + 2;
 104                 break;
 105         }
 106         if (!ascii)
 107                 goto nil;
 108
 109         while (lx < (linebuflen - 1) && lx < (ascii_column - 1))
 110                 linebuf[lx++] = ' ';
 111         for (j = 0; (j < rowsize) && (j < len) && (lx + 2) < linebuflen; j++)
 112                 linebuf[lx++] = (isascii(ptr[j]) && isprint(ptr[j])) ? ptr[j]
 113                                 : '.';
 114 nil:
 115         linebuf[lx++] = '\0';
 116 }
 117 EXPORT_SYMBOL(hex_dump_to_buffer);
 118
 119 /**
 120  * print_hex_dump - print a text hex dump to syslog for a binary blob of data
 121  * @level: kernel log level (e.g. KERN_DEBUG)
 122  * @prefix_str: string to prefix each line with;
 123  *  caller supplies trailing spaces for alignment if desired
 124  * @prefix_type: controls whether prefix of an offset, address, or none
 125  *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
 126  * @rowsize: number of bytes to print per line; must be 16 or 32
 127  * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
 128  * @buf: data blob to dump
 129  * @len: number of bytes in the @buf
 130  * @ascii: include ASCII after the hex output
 131  *
 132  * Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump
 133  * to the kernel log at the specified kernel log level, with an optional
 134  * leading prefix.
 135  *
 136  * print_hex_dump() works on one "line" of output at a time, i.e.,
 137  * 16 or 32 bytes of input data converted to hex + ASCII output.
 138  * print_hex_dump() iterates over the entire input @buf, breaking it into
 139  * "line size" chunks to format and print.
 140  *
 141  * E.g.:
 142  *   print_hex_dump(KERN_DEBUG, "raw data: ", DUMP_PREFIX_ADDRESS,
 143  *              16, 1, frame->data, frame->len, 1);
 144  *
 145  * Example output using %DUMP_PREFIX_OFFSET and 1-byte mode:
 146  * 0009ab42: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f  @ABCDEFGHIJKLMNO
 147  * Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode:
 148  * ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c  pqrstuvwxyz{|}~.
 149  */
 150 void print_hex_dump(const char *level, const char *prefix_str, int prefix_type,
 151                         int rowsize, int groupsize,
 152                         const void *buf, size_t len, bool ascii)
 153 {
 154         const u8 *ptr = buf;
 155         int i, linelen, remaining = len;
 156         unsigned char linebuf[200];
 157
 158         if (rowsize != 16 && rowsize != 32)
 159                 rowsize = 16;
 160
 161         for (i = 0; i < len; i += rowsize) {
 162                 linelen = min(remaining, rowsize);
 163                 remaining -= rowsize;
 164                 hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
 165                                 linebuf, sizeof(linebuf), ascii);
 166
 167                 switch (prefix_type) {
 168                 case DUMP_PREFIX_ADDRESS:
 169                         printk("%s%s%*p: %s\n", level, prefix_str,
 170                                 (int)(2 * sizeof(void *)), ptr + i, linebuf);
 171                         break;
 172                 case DUMP_PREFIX_OFFSET:
 173                         printk("%s%s%.8x: %s\n", level, prefix_str, i, linebuf);
 174                         break;
 175                 default:
 176                         printk("%s%s%s\n", level, prefix_str, linebuf);
 177                         break;
 178                 }
 179         }
 180 }
 181 EXPORT_SYMBOL(print_hex_dump);
 182
 183 /**
 184  * print_hex_dump_bytes - shorthand form of print_hex_dump() with default params
 185  * @prefix_str: string to prefix each line with;
 186  *  caller supplies trailing spaces for alignment if desired
 187  * @prefix_type: controls whether prefix of an offset, address, or none
 188  *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
 189  * @buf: data blob to dump
 190  * @len: number of bytes in the @buf
 191  *
 192  * Calls print_hex_dump(), with log level of KERN_DEBUG,
 193  * rowsize of 16, groupsize of 1, and ASCII output included.
 194  */
 195 void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
 196                         const void *buf, size_t len)
 197 {
 198         print_hex_dump(KERN_DEBUG, prefix_str, prefix_type, 16, 1,
 199                         buf, len, 1);
 200 }
 201 EXPORT_SYMBOL(print_hex_dump_bytes);