how to convert ascii to hexdump & Binary to hexdump in kernel module - linux-kernel

Question

I am writing a Kernel module,
Module supports conversion of ASCII data to Hexdump and Binary data to Hexdump and print it through cat.
without using hexdump utility (part of util-linux)
Thanks in advance.

Answer 1

This is program for converting ascii to hex:
*/
#include <stdio.h>
#include <stdlib.h>
void hexdump(unsigned char *buffer, unsigned long index, unsigned long width)
{
unsigned long i;
for (i=0;i<index;i++)
{
printf("%02x ",buffer[i]);
}
for (unsigned long spacer=index;spacer<width;spacer++)
printf(" ");
printf(": ");
for (i=0;i<index;i++)
{
if (buffer[i] < 32) printf(".");
else printf("%c",buffer[i]);
}
printf("\n");
}
int hexdump_file(FILE *infile,unsigned long start, unsigned long stop, unsigned long width)
{
char ch;
unsigned long f_index=0;
unsigned long bb_index=0;
unsigned char *byte_buffer = malloc(width);
if (byte_buffer == NULL)
{
printf("Could not allocate memory for byte_buffer\n");
return -1;
}
while (!feof(infile))
{
ch = getc(infile);
if ((f_index >= start)&&(f_index <= stop))
{
byte_buffer[bb_index] = ch;
bb_index++;
}
if (bb_index >= width)
{
hexdump(byte_buffer,bb_index,width);
bb_index=0;
}
f_index++;
}
if (bb_index)
hexdump(byte_buffer,bb_index,width);
fclose(infile);
free(byte_buffer);
return 0;
}
int main(int argc, char *argv[])
{
if (argc != 5)
{
printf("Usage: hexdump <infile> <start> <end> <width>\n");
return 0;
}
FILE *infile=fopen(argv[1],"rb");
if (infile==(FILE *)NULL)
{
printf("Error opening input file %s\n",argv[1]);
return 0;
}
printf("Filename: \"%s\"\n", argv[1]);
printf("Start : %lu\n", atoi(argv[2]));
printf("End : %lu\n", atoi(argv[3]));
printf("Bytes per Line: %lu\n",atoi(argv[4]));
int result = hexdump_file(infile,atoi(argv[2]),atoi(argv[3]),atoi(argv[4]));
return 0;
}
Run output:
$ hexdump hexdump.c 0 100 16
Filename: "hexdump.c"
Start : 0
End : 100
Bytes per Line: 16
2f 2a 0d 0a 20 20 54 68 69 73 20 65 6e 74 72 79 : /*.. This entry
20 63 6f 6e 74 61 69 6e 73 20 63 65 72 74 61 69 : contains certai
6e 20 66 75 6e 63 74 69 6f 6e 61 6c 69 74 79 20 : n functionality
74 68 65 20 6f 74 68 65 72 73 20 6d 61 79 20 6e : the others may n
6f 74 2e 0d 0a 20 20 20 20 2a 20 54 68 65 20 73 : ot... * The s
74 6f 70 2d 73 74 61 72 74 20 73 70 61 6e 20 64 : top-start span d
6f 65 73 20 6e : oes n
Thanks & Regards
Satish.G