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Extract sequences of bytes from binary for differents blocks

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Top Forums Shell Programming and Scripting Extract sequences of bytes from binary for differents blocks
# 43  
Old 08-25-2013
Yes, only I don't know why is no printing each of the 14 bytes separated by "|".
Only the fisrt 2 bytes after 0x0e are printing separated.
# 44  
Old 08-26-2013
That is because you never asked for that. Check your post #29, sub block sequences are printed based on that.

--ahamed

---------- Post updated at 08:37 PM ---------- Previous update was at 11:06 AM ----------

For removing f's. If in a single byte there is a trailing f, that will be masked.

Code:
#define DONT_PRINT1 0xff
#define DONT_PRINT2 0x0f
#define MASK 0x0f
#define INV_MASK 0xf0

void print_bytes(const unsigned char *ptr, int len, block bl)
{
        int i;
        unsigned char op;
        for(i=0;i<len;i++){
                if(MAIN_BLOCK == bl){
                        op = ptr[i] & MASK;

                        if(ptr[i] == DONT_PRINT1)
                                continue;

                        if(  ((i == (len-1)) && !(op ^ DONT_PRINT2)) 
                          || (!(op ^ DONT_PRINT2) && (ptr[i+1] && (ptr[i+1] == DONT_PRINT1))) ){

                                op = ptr[i] & INV_MASK;
                                if(op){
                                        printf("%x", op);
                                }
                                continue;
                        }
                }
                printf("%02x", ptr[i]);
        }
        printf("|");
        return;

}

void print_data(const unsigned char *ptr, int len, block bl)
{
        if(MAIN_BLOCK == bl){
                print_bytes(ptr, 1, bl);
                print_bytes(ptr+1, 3, bl);
                print_bytes(ptr+4, 8, bl);
                print_bytes(ptr+12, 8, bl);
        } else {
                print_bytes(ptr, 1, bl);
                print_bytes(ptr+1, 1, bl);
                print_bytes(ptr+2, 1, bl);
                print_bytes(ptr+3, 1, bl);
                print_bytes(ptr+4, 4, bl);
                print_bytes(ptr+8, 8, bl);
                print_bytes(ptr+16, 1, bl);
                if(*ptr == intrim_pat1[2][1]){
                        print_bytes(ptr+17, 1, bl);
                }
        }
        return;
}

--ahamed
# 45  
Old 08-26-2013
Hello ahamed,

Really help! it works wonderful. I've learned many things from C from your code and logic and methods used, almost I didn't now anything of C before.

I think the code would be a little smaller because since pat2 has a fixed number of bytes and is always after the 8 bytes of pat1, maybe both could be
a single pat joined. Doesn't matter, I didn't explain very well that at the beginning.

I was able to add/modify (in red) some things to your code in order to remove f's y Sub-block too and print separated the las 14 bytes.
Code:
typedef enum {
        MAIN_BLOCK,
        SUB_BLOCK,
        SUB_BLOCK1
} block;

void print_bytes(const unsigned char *ptr, int len, block bl)
{
        int i;
        unsigned char op;
        for(i=0;i<len;i++){
                if((MAIN_BLOCK == bl) || (SUB_BLOCK == bl)){
                        op = ptr[i] & MASK;

                        if(ptr[i] == DONT_PRINT1)
                                continue;

                        if(  ((i == (len-1)) && !(op ^ DONT_PRINT2)) 
                          || (!(op ^ DONT_PRINT2) && (ptr[i+1] && (ptr[i+1] == DONT_PRINT1))) ){

                                op = ptr[i] & INV_MASK;
                                if(op){
                                        printf("%x", op);
                                }
                                continue;
                        }                        
                printf("%02x", ptr[i]);
                }
                else if(SUB_BLOCK1 == bl) {
                    printf("%02x", ptr[i]);
                }
        }
        printf("|");
        return;
}
void print_bytes_each(const unsigned char *ptr, int len)
{
        int i;
        for(i=0;i<len;i++)
                printf("%02x|", ptr[i]);
        return;
}
void print_data(const unsigned char *ptr, int len, block bl)
{
        if(MAIN_BLOCK == bl){
                print_bytes(ptr, 1, bl);
                print_bytes(ptr+1, 3, bl);
                print_bytes(ptr+4, 8, bl);
                print_bytes(ptr+12, 8, bl);
        } else if(SUB_BLOCK == bl){
                print_bytes(ptr, 1, bl);
                print_bytes(ptr+1, 1, bl);
                print_bytes(ptr+2, 1, bl);
                print_bytes(ptr+3, 1, bl);
                print_bytes(ptr+4, 4, bl);
                print_bytes(ptr+8, 8, bl);
                print_bytes(ptr+16, 1, bl);
                if(*ptr == intrim_pat1[2][1]){
                        print_bytes(ptr+17, 1, bl);
                }
        } else if(SUB_BLOCK1 == bl) {
		print_bytes(ptr, 1, bl); 
                print_bytes_each(ptr+2, 14); 
		 }
        return;
}
void get_len_and_print(FILE *fp, unsigned char *ptr)
{
        int len = 0;

        //only buf[0] is populated at this stage
        if(1 != fread(ptr+1, sizeof(char), 1, fp))
                err("Insufficient data");
        len = *(ptr+1);
        
        if(len !=14){
                if(len != fread(ptr+2, sizeof(char), len, fp))
                   err("Insufficient data");
                print_data(ptr, len+1, SUB_BLOCK);
        }
        else if(len == 14){
                if(len != fread(ptr+2, sizeof(char), len, fp))
                       err("Insufficient data");
                print_data(ptr, len, SUB_BLOCK1);            
        }        
        return;
}

One question I have is, can pat1 and pat2 controlled outside the code by user? Now they are fixed written inside the code. I think
something like when running the program, it asks for pat1 and pat2 (or better, asks for pat1 only).
example:
"Introduce pat1"
and after enter the pattern 991145, the code would run.

Many thanks for all your great help during these days ahamed!

Best regards
# 46  
Old 08-27-2013
You can use the command line arguments and initialize the pattern array
Here is an example

Code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define err(x) {printf("Error : %s...\n", x); exit(1);}

int main(int argc, char **argv)
{

        if(argc <= 1){
                err("Insufficient arguments");
        }

        unsigned char pat[32];
        int count = 0, i;

        while(argv[count+1] != NULL){
                if(strlen(argv[count+1]) > 2)
                        err("Invalid data provided")
                if(!sscanf(argv[count+1], "%2hhx", &pat[count]))
                        err("Invalid data provided")
                count++;
        }

        printf("\n");
        for(i=0; i<count; i++){
                printf("0x%02x ", pat[i]);
        }
        printf("\n");

        return 0;
}

Code:
-bash-3.2$ gcc run.c -o run
-bash-3.2$ ./run 99 11 45

0x99 0x11 0x45

--ahamed
# 47  
Old 08-31-2013
Hello ahamed again,

Thanks for the help in the last question.

Now, I hope you can help me to see what could be this issue. I'm attaching the final code I'm using, added some functions to your original code.

I'm trying with a binary file of 2GB and when the output file reaches 581,525 lines and 38 MB, simply stops the processing and the error below appears:
Code:
Aborted (`core' generated)

and inside the stackdump file generated says:
Code:
Stack trace:
Frame     Function  Args

Many thanks in advance.
script.txt (8.7 KB) 
# 48  
Old 08-31-2013
If you have a file approaching 2GB in size the result of ftell() will overflow the pos variable, you are best defining pos as a long variable.

Try again after you replace this:

Code:
        int pos = 0, i, len;

with this:

Code:
        long pos = 0L;
        int i, len;

# 49  
Old 08-31-2013
Hello Chubler_XL!

Thanks for your interventions.

I've tried modifying as you suggested but happens exactly the same. It stops exactly when
the size reaches 39,296 KB.

The error is the same.
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