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 *--------------------------------------------------------------------------*/
hexdump(const void * mem,int bytes,uint64_t addrprint_start,FILE * outfile,const hexdump_format_t * format)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 *--------------------------------------------------------------------------*/
addrprint(FILE * outfile,uint64_t address,int width)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 }
147