NeXT/Examples/pppkill.c

   1 Many thanks to:
   2    shess@winternet.com (Scott Hess)
   3    andrew_abernathy@wire.seanet.com (Andrew Abernathy)
   4    michal@ellpspace.math.ualberta.ca (Michal Jaegermann)
   5
   6 for contributing programs that can take the place
   7 of the pppdown script.  I have included Scott Hess's
   8 (now modified) here.  If you would like to see the other program, please
   9 mail Andrew.
  10
  11 ======================================================================
  12
  13 From shess@winternet.com Mon Jan  9 02:45 EST 1995
  14 Date: Mon, 9 Jan 95 01:45 CST
  15 From: shess@winternet.com (Scott Hess)
  16 Reply-To: shess@winternet.com (Scott Hess)
  17 To: Steve Perkins <perkins@cps.msu.edu>
  18 Subject: Bringing down ppp.
  19
  20 [munch]
  21
  22 In any case, having to run pppdown as root has been annoying,
  23 because I don't like to run things as root more than necessary.
  24 In other words, more than about once a week is too often :-).  So,
  25 I wrote the following quick&dirty hack.  Basic operation is to read
  26 the pppd pid from a file where it's stored and send a SIGINT to
  27 that process.  Since there's not a shell script in sight, this
  28 should be a reasonably safe program to make setuid root.  [I'll
  29 have to think on what someone can do if they crack it or /etc/ppp
  30 and can send SIGINT to just anyone.  Perhaps it should check to
  31 see if the process is really a pppd?  Oh, well.]
  32
  33 howard:/tmp> ls -l /usr/local/ppp/bin/killppp
  34
  35 -rwsr-sr-x  1 root        1464 Jan  7 12:41 /usr/local/ppp/bin/killppp*
  36 howard:/tmp> cat /usr/local/ppp/src/killppp.c
  37
  38 /*
  39  * Originally written by Scott Hess <shess@winternet.com>
  40  * and later modified by Michal Jaegermann  <michal@ellpspace.math.ualberta.ca>
  41  */
  42
  43 #include <libc.h>
  44 #include <stdio.h>
  45
  46
  47 #include <libc.h>
  48 #include <stdio.h>
  49
  50 #define PIDF "/etc/ppp/ppp0.pid"
  51
  52 int
  53 main( void)
  54 {
  55     FILE *ff;
  56     int pid;
  57
  58
  59     if( NULL == (ff = fopen( PIDF, "r"))) {
  60         perror( "opening " PIDF
  61         "\nppp0 link does not seem to be active" );
  62         exit(1);
  63     }
  64
  65
  66     if( fscanf( ff, "%d", &pid)<1) {
  67         fprintf( stderr, "Cannot read pid from" PIDF "\n");
  68         exit(1);
  69     }
  70
  71
  72     fclose( ff);
  73     if( kill( pid, SIGINT)==-1) {
  74         perror( "killing pppd");
  75         fprintf( stderr, "removing stale" PIDF "file\n");
  76         if (0 != unlink( PIDF)) {
  77             perror("cannot remove" PIDF);
  78         }
  79         exit(1);
  80     }
  81     return 0;
  82 }
  83
  84 Later,
  85 ---
  86 scott hess <shess@winternet.com> (WWW to "http://www.winternet.com/~shess/")
  87 Home:   12901 Upton Avenue South, #326  Burnsville, MN 55337  (612) 895-1208
  88 Office: 101 W. Burnsville Pkwy, Suite 108E, Burnsville, MN 55337    890-1332
  89 <?If you haven't the time to design, where will you find the time to debug?>
  90