sysvinit-2.86/src/wall.c

   1 /*
   2  * wall.c       Write to all users logged in.
   3  *
   4  * Usage:       wall [text]
   5  *
   6  * Version:     @(#)wall  2.79  12-Sep-2000  miquels@cistron.nl
   7  *
   8  *              This file is part of the sysvinit suite,
   9  *              Copyright 1991-2000 Miquel van Smoorenburg.
  10  *
  11  *              This program is free software; you can redistribute it and/or
  12  *              modify it under the terms of the GNU General Public License
  13  *              as published by the Free Software Foundation; either version
  14  *              2 of the License, or (at your option) any later version.
  15  */
  16
  17 #include <stdio.h>
  18 #include <string.h>
  19 #include <stdlib.h>
  20 #include <unistd.h>
  21 #include <pwd.h>
  22 #include <syslog.h>
  23
  24
  25 char *Version = "@(#) wall 2.79 12-Sep-2000 miquels@cistron.nl";
  26 #define MAXLEN 4096
  27 #define MAXLINES 20
  28
  29 extern void wall(char *, int, int);
  30
  31 int main(int argc, char **argv)
  32 {
  33   char buf[MAXLEN];
  34   char line[83];
  35   int i, f, ch;
  36   int len = 0;
  37   int remote = 0;
  38   char *p;
  39   char *whoami;
  40   struct passwd *pwd;
  41
  42   buf[0] = 0;
  43   if ((pwd = getpwuid(getuid())) == NULL) {
  44         if (getuid() == 0)
  45                 whoami = "root";
  46         else {
  47                 fprintf(stderr, "You don't exist. Go away.\n");
  48                 exit(1);
  49         }
  50   } else
  51         whoami = pwd->pw_name;
  52
  53   while((ch = getopt(argc, argv, "n")) != EOF)
  54         switch(ch) {
  55                 case 'n':
  56                         /*
  57                          *      Undocumented option for suppressing
  58                          *      banner from rpc.rwalld. Only works if
  59                          *      we are root or if we're NOT setgid.
  60                          */
  61                         if (geteuid() != 0 && getgid() != getegid()) {
  62                                 fprintf(stderr, "wall -n: not priviliged\n");
  63                                 exit(1);
  64                         }
  65                         remote = 1;
  66                         break;
  67                 default:
  68                         fprintf(stderr, "usage: wall [message]\n");
  69                         return 1;
  70                         break;
  71         }
  72
  73   if ((argc - optind) > 0) {
  74         for(f = optind; f < argc; f++) {
  75                 len += strlen(argv[f]) + 1;
  76                 if (len >= MAXLEN-2) break;
  77                 strcat(buf, argv[f]);
  78                 if (f < argc-1) strcat(buf, " ");
  79         }
  80         strcat(buf, "\r\n");
  81   } else {
  82         while(fgets(line, 80, stdin)) {
  83                 /*
  84                  *      Make sure that line ends in \r\n
  85                  */
  86                 for(p = line; *p && *p != '\r' && *p != '\n'; p++)
  87                         ;
  88                 strcpy(p, "\r\n");
  89                 len += strlen(line);
  90                 if (len >= MAXLEN) break;
  91                 strcat(buf, line);
  92         }
  93   }
  94
  95   i = 0;
  96   for (p = buf; *p; p++) {
  97         if (*p == '\n' && i++ > MAXLINES) {
  98                 *++p = 0;
  99                 break;
 100         }
 101   }
 102
 103   openlog("wall", LOG_PID, LOG_USER);
 104   syslog(LOG_INFO, "wall: user %s broadcasted %d lines (%d chars)",
 105         whoami, i, strlen(buf));
 106   closelog();
 107
 108   unsetenv("TZ");
 109   wall(buf, 0, remote);
 110
 111   /*NOTREACHED*/
 112   return 0;
 113 }
 114