util/nvramtool/hexdump.c

   1 /* SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0-only */
   2
   3 #include "hexdump.h"
   4 #include <ctype.h>
   5
   6 static void addrprint(FILE * outfile, uint64_t address, int width);
   7
   8 /*--------------------------------------------------------------------------
   9  * hexdump
  10  *
  11  * Write a hex dump of 'mem' to 'outfile'.
  12  *
  13  * parameters:
  14  *     mem:             a pointer to the memory to display
  15  *     bytes:           the number of bytes of data to display
  16  *     addrprint_start: The address to associate with the first byte of
  17  *                      data.  For instance, a value of 0 indicates that the
  18  *                      first byte displayed should be labeled as byte 0.
  19  *     outfile:         The place where the hex dump should be written.
  20  *                      For instance, stdout or stderr may be passed here.
  21  *     format:          A structure specifying how the hex dump should be
  22  *                      formatted.
  23  *--------------------------------------------------------------------------*/
  24 void hexdump(const void *mem, int bytes, uint64_t addrprint_start,
  25              FILE * outfile, const hexdump_format_t * format)
  26 {
  27         int bytes_left, index, i;
  28         const unsigned char *p;
  29
  30         /* Quietly return if the caller asks us to do something unreasonable. */
  31         if ((format->bytes_per_line <= 0) || (bytes < 0))
  32                 return;
  33
  34         p = (const unsigned char *)mem;
  35         index = 0;
  36
  37         /* Each iteration handles one full line of output.  When loop
  38          * terminates, the number of remaining bytes to display (if any)
  39          * will not be enough to fill an entire line.
  40          */
  41         for (bytes_left = bytes;
  42                         bytes_left >= format->bytes_per_line;
  43                         bytes_left -= format->bytes_per_line) {
  44                 /* print start address for current line */
  45                 fprintf(outfile, "%s", format->indent);
  46                 addrprint(outfile, addrprint_start + index,
  47                           format->addrprint_width);
  48                 fprintf(outfile, "%s", format->sep1);
  49
  50                 /* display the bytes in hex */
  51                 for (i = 0;;) {
  52                         fprintf(outfile, "%02x", p[index++]);
  53
  54                         if (++i >= format->bytes_per_line)
  55                                 break;
  56
  57                         fprintf(outfile, "%s", format->sep2);
  58                 }
  59
  60                 index -= format->bytes_per_line;
  61                 fprintf(outfile, "%s", format->sep3);
  62
  63                 /* display the bytes as characters */
  64                 for (i = 0; i < format->bytes_per_line; i++, index++)
  65                         fputc(isprint(p[index])?p[index]:format->nonprintable, outfile);
  66
  67                 fprintf(outfile, "\n");
  68         }
  69
  70         if (bytes_left == 0)
  71                 return;
  72
  73         /* print start address for last line */
  74         fprintf(outfile, "%s", format->indent);
  75         addrprint(outfile, addrprint_start + index, format->addrprint_width);
  76         fprintf(outfile, "%s", format->sep1);
  77
  78         /* display bytes for last line in hex */
  79         for (i = 0; i < bytes_left; i++) {
  80                 fprintf(outfile, "%02x", p[index++]);
  81                 fprintf(outfile, "%s", format->sep2);
  82         }
  83
  84         index -= bytes_left;
  85
  86         /* pad the rest of the hex byte area with spaces */
  87         for (;;) {
  88                 fprintf(outfile, "  ");
  89
  90                 if (++i >= format->bytes_per_line)
  91                         break;
  92
  93                 fprintf(outfile, "%s", format->sep2);
  94         }
  95
  96         fprintf(outfile, "%s", format->sep3);
  97
  98         /* display bytes for last line as characters */
  99         for (i = 0; i < bytes_left; i++)
 100                 fputc(isprint(p[index])?p[index++]:format->nonprintable, outfile);
 101
 102         /* pad the rest of the character area with spaces */
 103         for (; i < format->bytes_per_line; i++)
 104                 fprintf(outfile, " ");
 105
 106         fprintf(outfile, "\n");
 107 }
 108
 109 /*--------------------------------------------------------------------------
 110  * addrprint
 111  *
 112  * Display an address as a hexadecimal number.
 113  *
 114  * parameters:
 115  *     outfile: the place where the output should be written
 116  *     address: the address to display
 117  *     width:   The number of bytes wide the address should be displayed as.
 118  *              Must be a value from 1 to 8.
 119  *--------------------------------------------------------------------------*/
 120 static void addrprint(FILE * outfile, uint64_t address, int width)
 121 {
 122         char s[17];
 123         int i;
 124
 125         /* force the user's input to be valid */
 126         if (width < 1)
 127                 width = 1;
 128         else if (width > 8)
 129                 width = 8;
 130
 131         /* convert address to string */
 132         sprintf(s, "%016llx", (unsigned long long)address);
 133
 134         /* write it out, with colons separating consecutive 16-bit
 135          * chunks of the address
 136          */
 137         for (i = 16 - (2 * width);;) {
 138                 fprintf(outfile, "%c", s[i]);
 139
 140                 if (++i >= 16)
 141                         break;
 142
 143                 if ((i % 4) == 0)
 144                         fprintf(outfile, ":");
 145         }
 146 }