lib/hexdump.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * lib/hexdump.c
   4  */
   5
   6 #include <linux/types.h>
   7 #include <linux/ctype.h>
   8 #include <linux/errno.h>
   9 #include <linux/kernel.h>
  10 #include <linux/export.h>
  11 #include <asm/unaligned.h>
  12
  13 const char hex_asc[] = "0123456789abcdef";
  14 EXPORT_SYMBOL(hex_asc);
  15 const char hex_asc_upper[] = "0123456789ABCDEF";
  16 EXPORT_SYMBOL(hex_asc_upper);
  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  * hex2bin - convert an ascii hexadecimal string to its binary representation
  38  * @dst: binary result
  39  * @src: ascii hexadecimal string
  40  * @count: result length
  41  *
  42  * Return 0 on success, -EINVAL in case of bad input.
  43  */
  44 int hex2bin(u8 *dst, const char *src, size_t count)
  45 {
  46         while (count--) {
  47                 int hi = hex_to_bin(*src++);
  48                 int lo = hex_to_bin(*src++);
  49
  50                 if ((hi < 0) || (lo < 0))
  51                         return -EINVAL;
  52
  53                 *dst++ = (hi << 4) | lo;
  54         }
  55         return 0;
  56 }
  57 EXPORT_SYMBOL(hex2bin);
  58
  59 /**
  60  * bin2hex - convert binary data to an ascii hexadecimal string
  61  * @dst: ascii hexadecimal result
  62  * @src: binary data
  63  * @count: binary data length
  64  */
  65 char *bin2hex(char *dst, const void *src, size_t count)
  66 {
  67         const unsigned char *_src = src;
  68
  69         while (count--)
  70                 dst = hex_byte_pack(dst, *_src++);
  71         return dst;
  72 }
  73 EXPORT_SYMBOL(bin2hex);
  74
  75 /**
  76  * hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
  77  * @buf: data blob to dump
  78  * @len: number of bytes in the @buf
  79  * @rowsize: number of bytes to print per line; must be 16 or 32
  80  * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
  81  * @linebuf: where to put the converted data
  82  * @linebuflen: total size of @linebuf, including space for terminating NUL
  83  * @ascii: include ASCII after the hex output
  84  *
  85  * hex_dump_to_buffer() works on one "line" of output at a time, i.e.,
  86  * 16 or 32 bytes of input data converted to hex + ASCII output.
  87  *
  88  * Given a buffer of u8 data, hex_dump_to_buffer() converts the input data
  89  * to a hex + ASCII dump at the supplied memory location.
  90  * The converted output is always NUL-terminated.
  91  *
  92  * E.g.:
  93  *   hex_dump_to_buffer(frame->data, frame->len, 16, 1,
  94  *                      linebuf, sizeof(linebuf), true);
  95  *
  96  * example output buffer:
  97  * 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f  @ABCDEFGHIJKLMNO
  98  *
  99  * Return:
 100  * The amount of bytes placed in the buffer without terminating NUL. If the
 101  * output was truncated, then the return value is the number of bytes
 102  * (excluding the terminating NUL) which would have been written to the final
 103  * string if enough space had been available.
 104  */
 105 int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupsize,
 106                        char *linebuf, size_t linebuflen, bool ascii)
 107 {
 108         const u8 *ptr = buf;
 109         int ngroups;
 110         u8 ch;
 111         int j, lx = 0;
 112         int ascii_column;
 113         int ret;
 114
 115         if (rowsize != 16 && rowsize != 32)
 116                 rowsize = 16;
 117
 118         if (len > rowsize)              /* limit to one line at a time */
 119                 len = rowsize;
 120         if (!is_power_of_2(groupsize) || groupsize > 8)
 121                 groupsize = 1;
 122         if ((len % groupsize) != 0)     /* no mixed size output */
 123                 groupsize = 1;
 124
 125         ngroups = len / groupsize;
 126         ascii_column = rowsize * 2 + rowsize / groupsize + 1;
 127
 128         if (!linebuflen)
 129                 goto overflow1;
 130
 131         if (!len)
 132                 goto nil;
 133
 134         if (groupsize == 8) {
 135                 const u64 *ptr8 = buf;
 136
 137                 for (j = 0; j < ngroups; j++) {
 138                         ret = snprintf(linebuf + lx, linebuflen - lx,
 139                                        "%s%16.16llx", j ? " " : "",
 140                                        get_unaligned(ptr8 + j));
 141                         if (ret >= linebuflen - lx)
 142                                 goto overflow1;
 143                         lx += ret;
 144                 }
 145         } else if (groupsize == 4) {
 146                 const u32 *ptr4 = buf;
 147
 148                 for (j = 0; j < ngroups; j++) {
 149                         ret = snprintf(linebuf + lx, linebuflen - lx,
 150                                        "%s%8.8x", j ? " " : "",
 151                                        get_unaligned(ptr4 + j));
 152                         if (ret >= linebuflen - lx)
 153                                 goto overflow1;
 154                         lx += ret;
 155                 }
 156         } else if (groupsize == 2) {
 157                 const u16 *ptr2 = buf;
 158
 159                 for (j = 0; j < ngroups; j++) {
 160                         ret = snprintf(linebuf + lx, linebuflen - lx,
 161                                        "%s%4.4x", j ? " " : "",
 162                                        get_unaligned(ptr2 + j));
 163                         if (ret >= linebuflen - lx)
 164                                 goto overflow1;
 165                         lx += ret;
 166                 }
 167         } else {
 168                 for (j = 0; j < len; j++) {
 169                         if (linebuflen < lx + 2)
 170                                 goto overflow2;
 171                         ch = ptr[j];
 172                         linebuf[lx++] = hex_asc_hi(ch);
 173                         if (linebuflen < lx + 2)
 174                                 goto overflow2;
 175                         linebuf[lx++] = hex_asc_lo(ch);
 176                         if (linebuflen < lx + 2)
 177                                 goto overflow2;
 178                         linebuf[lx++] = ' ';
 179                 }
 180                 if (j)
 181                         lx--;
 182         }
 183         if (!ascii)
 184                 goto nil;
 185
 186         while (lx < ascii_column) {
 187                 if (linebuflen < lx + 2)
 188                         goto overflow2;
 189                 linebuf[lx++] = ' ';
 190         }
 191         for (j = 0; j < len; j++) {
 192                 if (linebuflen < lx + 2)
 193                         goto overflow2;
 194                 ch = ptr[j];
 195                 linebuf[lx++] = (isascii(ch) && isprint(ch)) ? ch : '.';
 196         }
 197 nil:
 198         linebuf[lx] = '\0';
 199         return lx;
 200 overflow2:
 201         linebuf[lx++] = '\0';
 202 overflow1:
 203         return ascii ? ascii_column + len : (groupsize * 2 + 1) * ngroups - 1;
 204 }
 205 EXPORT_SYMBOL(hex_dump_to_buffer);
 206
 207 #ifdef CONFIG_PRINTK
 208 /**
 209  * print_hex_dump - print a text hex dump to syslog for a binary blob of data
 210  * @level: kernel log level (e.g. KERN_DEBUG)
 211  * @prefix_str: string to prefix each line with;
 212  *  caller supplies trailing spaces for alignment if desired
 213  * @prefix_type: controls whether prefix of an offset, address, or none
 214  *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
 215  * @rowsize: number of bytes to print per line; must be 16 or 32
 216  * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
 217  * @buf: data blob to dump
 218  * @len: number of bytes in the @buf
 219  * @ascii: include ASCII after the hex output
 220  *
 221  * Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump
 222  * to the kernel log at the specified kernel log level, with an optional
 223  * leading prefix.
 224  *
 225  * print_hex_dump() works on one "line" of output at a time, i.e.,
 226  * 16 or 32 bytes of input data converted to hex + ASCII output.
 227  * print_hex_dump() iterates over the entire input @buf, breaking it into
 228  * "line size" chunks to format and print.
 229  *
 230  * E.g.:
 231  *   print_hex_dump(KERN_DEBUG, "raw data: ", DUMP_PREFIX_ADDRESS,
 232  *                  16, 1, frame->data, frame->len, true);
 233  *
 234  * Example output using %DUMP_PREFIX_OFFSET and 1-byte mode:
 235  * 0009ab42: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f  @ABCDEFGHIJKLMNO
 236  * Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode:
 237  * ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c  pqrstuvwxyz{|}~.
 238  */
 239 void print_hex_dump(const char *level, const char *prefix_str, int prefix_type,
 240                     int rowsize, int groupsize,
 241                     const void *buf, size_t len, bool ascii)
 242 {
 243         const u8 *ptr = buf;
 244         int i, linelen, remaining = len;
 245         unsigned char linebuf[32 * 3 + 2 + 32 + 1];
 246
 247         if (rowsize != 16 && rowsize != 32)
 248                 rowsize = 16;
 249
 250         for (i = 0; i < len; i += rowsize) {
 251                 linelen = min(remaining, rowsize);
 252                 remaining -= rowsize;
 253
 254                 hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
 255                                    linebuf, sizeof(linebuf), ascii);
 256
 257                 switch (prefix_type) {
 258                 case DUMP_PREFIX_ADDRESS:
 259                         printk("%s%s%p: %s\n",
 260                                level, prefix_str, ptr + i, linebuf);
 261                         break;
 262                 case DUMP_PREFIX_OFFSET:
 263                         printk("%s%s%.8x: %s\n", level, prefix_str, i, linebuf);
 264                         break;
 265                 default:
 266                         printk("%s%s%s\n", level, prefix_str, linebuf);
 267                         break;
 268                 }
 269         }
 270 }
 271 EXPORT_SYMBOL(print_hex_dump);
 272
 273 #endif /* defined(CONFIG_PRINTK) */