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  }