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 /**
  16  * hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
  17  * @buf: data blob to dump
  18  * @len: number of bytes in the @buf
  19  * @rowsize: number of bytes to print per line; must be 16 or 32
  20  * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
  21  * @linebuf: where to put the converted data
  22  * @linebuflen: total size of @linebuf, including space for terminating NUL
  23  * @ascii: include ASCII after the hex output
  24  *
  25  * hex_dump_to_buffer() works on one "line" of output at a time, i.e.,
  26  * 16 or 32 bytes of input data converted to hex + ASCII output.
  27  *
  28  * Given a buffer of u8 data, hex_dump_to_buffer() converts the input data
  29  * to a hex + ASCII dump at the supplied memory location.
  30  * The converted output is always NUL-terminated.
  31  *
  32  * E.g.:
  33  *   hex_dump_to_buffer(frame->data, frame->len, 16, 1,
  34  *                      linebuf, sizeof(linebuf), 1);
  35  *
  36  * example output buffer:
  37  * 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f  @ABCDEFGHIJKLMNO
  38  */
  39 void hex_dump_to_buffer(const void *buf, size_t len, int rowsize,
  40                         int groupsize, char *linebuf, size_t linebuflen,
  41                         bool ascii)
  42 {
  43         const u8 *ptr = buf;
  44         u8 ch;
  45         int j, lx = 0;
  46         int ascii_column;
  47
  48         if (rowsize != 16 && rowsize != 32)
  49                 rowsize = 16;
  50
  51         if (!len)
  52                 goto nil;
  53         if (len > rowsize)              /* limit to one line at a time */
  54                 len = rowsize;
  55         if ((len % groupsize) != 0)     /* no mixed size output */
  56                 groupsize = 1;
  57
  58         switch (groupsize) {
  59         case 8: {
  60                 const u64 *ptr8 = buf;
  61                 int ngroups = len / groupsize;
  62
  63                 for (j = 0; j < ngroups; j++)
  64                         lx += scnprintf(linebuf + lx, linebuflen - lx,
  65                                 "%16.16llx ", (unsigned long long)*(ptr8 + j));
  66                 ascii_column = 17 * ngroups + 2;
  67                 break;
  68         }
  69
  70         case 4: {
  71                 const u32 *ptr4 = buf;
  72                 int ngroups = len / groupsize;
  73
  74                 for (j = 0; j < ngroups; j++)
  75                         lx += scnprintf(linebuf + lx, linebuflen - lx,
  76                                 "%8.8x ", *(ptr4 + j));
  77                 ascii_column = 9 * ngroups + 2;
  78                 break;
  79         }
  80
  81         case 2: {
  82                 const u16 *ptr2 = buf;
  83                 int ngroups = len / groupsize;
  84
  85                 for (j = 0; j < ngroups; j++)
  86                         lx += scnprintf(linebuf + lx, linebuflen - lx,
  87                                 "%4.4x ", *(ptr2 + j));
  88                 ascii_column = 5 * ngroups + 2;
  89                 break;
  90         }
  91
  92         default:
  93                 for (j = 0; (j < rowsize) && (j < len) && (lx + 4) < linebuflen;
  94                      j++) {
  95                         ch = ptr[j];
  96                         linebuf[lx++] = hex_asc(ch >> 4);
  97                         linebuf[lx++] = hex_asc(ch & 0x0f);
  98                         linebuf[lx++] = ' ';
  99                 }
 100                 ascii_column = 3 * rowsize + 2;
 101                 break;
 102         }
 103         if (!ascii)
 104                 goto nil;
 105
 106         while (lx < (linebuflen - 1) && lx < (ascii_column - 1))
 107                 linebuf[lx++] = ' ';
 108         for (j = 0; (j < rowsize) && (j < len) && (lx + 2) < linebuflen; j++)
 109                 linebuf[lx++] = isprint(ptr[j]) ? ptr[j] : '.';
 110 nil:
 111         linebuf[lx++] = '\0';
 112 }
 113 EXPORT_SYMBOL(hex_dump_to_buffer);
 114
 115 /**
 116  * print_hex_dump - print a text hex dump to syslog for a binary blob of data
 117  * @level: kernel log level (e.g. KERN_DEBUG)
 118  * @prefix_str: string to prefix each line with;
 119  *  caller supplies trailing spaces for alignment if desired
 120  * @prefix_type: controls whether prefix of an offset, address, or none
 121  *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
 122  * @rowsize: number of bytes to print per line; must be 16 or 32
 123  * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
 124  * @buf: data blob to dump
 125  * @len: number of bytes in the @buf
 126  * @ascii: include ASCII after the hex output
 127  *
 128  * Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump
 129  * to the kernel log at the specified kernel log level, with an optional
 130  * leading prefix.
 131  *
 132  * print_hex_dump() works on one "line" of output at a time, i.e.,
 133  * 16 or 32 bytes of input data converted to hex + ASCII output.
 134  * print_hex_dump() iterates over the entire input @buf, breaking it into
 135  * "line size" chunks to format and print.
 136  *
 137  * E.g.:
 138  *   print_hex_dump(KERN_DEBUG, "raw data: ", DUMP_PREFIX_ADDRESS,
 139  *              16, 1, frame->data, frame->len, 1);
 140  *
 141  * Example output using %DUMP_PREFIX_OFFSET and 1-byte mode:
 142  * 0009ab42: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f  @ABCDEFGHIJKLMNO
 143  * Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode:
 144  * ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c  pqrstuvwxyz{|}~.
 145  */
 146 void print_hex_dump(const char *level, const char *prefix_str, int prefix_type,
 147                         int rowsize, int groupsize,
 148                         const void *buf, size_t len, bool ascii)
 149 {
 150         const u8 *ptr = buf;
 151         int i, linelen, remaining = len;
 152         unsigned char linebuf[200];
 153
 154         if (rowsize != 16 && rowsize != 32)
 155                 rowsize = 16;
 156
 157         for (i = 0; i < len; i += rowsize) {
 158                 linelen = min(remaining, rowsize);
 159                 remaining -= rowsize;
 160                 hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
 161                                 linebuf, sizeof(linebuf), ascii);
 162
 163                 switch (prefix_type) {
 164                 case DUMP_PREFIX_ADDRESS:
 165                         printk("%s%s%*p: %s\n", level, prefix_str,
 166                                 (int)(2 * sizeof(void *)), ptr + i, linebuf);
 167                         break;
 168                 case DUMP_PREFIX_OFFSET:
 169                         printk("%s%s%.8x: %s\n", level, prefix_str, i, linebuf);
 170                         break;
 171                 default:
 172                         printk("%s%s%s\n", level, prefix_str, linebuf);
 173                         break;
 174                 }
 175         }
 176 }
 177 EXPORT_SYMBOL(print_hex_dump);
 178
 179 /**
 180  * print_hex_dump_bytes - shorthand form of print_hex_dump() with default params
 181  * @prefix_str: string to prefix each line with;
 182  *  caller supplies trailing spaces for alignment if desired
 183  * @prefix_type: controls whether prefix of an offset, address, or none
 184  *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
 185  * @buf: data blob to dump
 186  * @len: number of bytes in the @buf
 187  *
 188  * Calls print_hex_dump(), with log level of KERN_DEBUG,
 189  * rowsize of 16, groupsize of 1, and ASCII output included.
 190  */
 191 void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
 192                         const void *buf, size_t len)
 193 {
 194         print_hex_dump(KERN_DEBUG, prefix_str, prefix_type, 16, 1,
 195                         buf, len, 1);
 196 }
 197 EXPORT_SYMBOL(print_hex_dump_bytes);