SET 39 Call For Papers

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Fuentes Extract

      1781

Autor: SET Staff
-[ 0x0F ]--------------------------------------------------------------------
-[ Extract ]-----------------------------------------------------------------
-[ by SET Staff ]-----------------------------------------------------SET-26-

  La habitual utilidad para extraer ficheros.

<++> utils/extract.c
/*  extract.c by Phrack Staff and sirsyko 
 *
 *  (c) Phrack Magazine, 1997 
 *      1.8.98 rewritten by route:
 *          - aesthetics
 *          - now accepts file globs
 *      todo:
 *          - more info in tag header (file mode, checksum)
 *  Extracts textfiles from a specially tagged flatfile into a hierarchical 
 *  directory strcuture.  Use to extract source code from any of the articles 
 *  in Phrack Magazine (first appeared in Phrack 50).
 *
 *  gcc -o extract extract.c
 *  
 *  ./extract file1 file2 file3 ...
 */

 
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <string.h>
#include <dirent.h>

#define BEGIN_TAG   "<++> "
#define END_TAG     "<-->"
#define BT_SIZE     strlen(BEGIN_TAG)
#define ET_SIZE     strlen(END_TAG)

struct f_name
{
    u_char name[256];
    struct f_name *next;
};

int
main(int argc, char **argv)
{ 
    u_char b[256], *bp, *fn;
    int i, j = 0;
    FILE *in_p, *out_p = NULL; 
    struct f_name *fn_p = NULL, *head = NULL; 

    if (argc < 2)
    {
        printf("Usage: %s file1 file2 ... filen\n", argv[0]);
        exit(0); 
    }

    /*
     *  Fill the f_name list with all the files on the commandline (ignoring
     *  argv[0] which is this executable).  This includes globs.
     */
    for (i = 1; (fn = argv[i++]); )
    {
        if (!head)
        {
            if (!(head = (struct f_name *)malloc(sizeof(struct f_name))))
            {
                perror("malloc");
                exit(1);
            }
            strncpy(head->name, fn, sizeof(head->name));
            head->next = NULL;
            fn_p = head;
        }
        else
        {
            if (!(fn_p->next = (struct f_name *)malloc(sizeof(struct f_name))))
            {
                perror("malloc");
                exit(1);
            }
            fn_p = fn_p->next;
            strncpy(fn_p->name, fn, sizeof(fn_p->name));
            fn_p->next = NULL;
        }
    }
    /*
     *  Sentry node.
     */
    if (!(fn_p->next = (struct f_name *)malloc(sizeof(struct f_name))))
    {
        perror("malloc");
        exit(1);
     }
    fn_p = fn_p->next;
    fn_p->next = NULL;

    /*
     *  Check each file in the f_name list for extraction tags.
     */
    for (fn_p = head; fn_p->next; fn_p = fn_p->next)
    {
        if (!(in_p = fopen(fn_p->name, "r")))
        {
            fprintf(stderr, "Could not open input file %s.\n", fn_p->name);
	    continue;
        }
        else fprintf(stderr, "Opened %s\n", fn_p->name);
        while (fgets(b, 256, in_p))
        { 
            if (!strncmp (b, BEGIN_TAG, BT_SIZE))
            { 
	        b[strlen(b) - 1] = 0;           /* Now we have a string. */
                j++;

                if ((bp = strchr(b + BT_SIZE + 1, '/')))
                {
                    while (bp)
                    {
		        *bp = 0;
		        mkdir(b + BT_SIZE, 0700); 
		        *bp = '/';
		        bp = strchr(bp + 1, '/'); 
		    }
                }
                if ((out_p = fopen(b + BT_SIZE, "w")))
                {
                    printf("- Extracting %s\n", b + BT_SIZE);
                }
                else
                {
		    printf("Could not extract '%s'.\n", b + BT_SIZE);
		    continue;
	        }
	    } 
            else if (!strncmp (b, END_TAG, ET_SIZE))
            {
	        if (out_p) fclose(out_p);
	        else
                {
	            fprintf(stderr, "Error closing file %s.\n", fn_p->name);
		    continue;
	        }
            } 
            else if (out_p)
            {
                fputs(b, out_p);
            }
        }
    }
    if (!j) printf("No extraction tags found in list.\n");
    else printf("Extracted %d file(s).\n", j);
    return (0);
}

/* EOF */
<-->