miscutils/wall.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * wall - write a message to all logged-in users
   4  * Copyright (c) 2009 Bernhard Reutner-Fischer
   5  *
   6  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   7  */
   8
   9 //usage:#define wall_trivial_usage
  10 //usage:        "[FILE]"
  11 //usage:#define wall_full_usage "\n\n"
  12 //usage:        "Write content of FILE or stdin to all logged-in users"
  13 //usage:
  14 //usage:#define wall_sample_usage
  15 //usage:        "echo foo | wall\n"
  16 //usage:        "wall ./mymessage"
  17
  18 #include "libbb.h"
  19
  20 int wall_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  21 int wall_main(int argc UNUSED_PARAM, char **argv)
  22 {
  23         struct utmp *ut;
  24         char *msg;
  25         int fd = argv[1] ? xopen(argv[1], O_RDONLY) : STDIN_FILENO;
  26
  27         msg = xmalloc_read(fd, NULL);
  28         if (ENABLE_FEATURE_CLEAN_UP && argv[1])
  29                 close(fd);
  30         setutent();
  31         while ((ut = getutent()) != NULL) {
  32                 char *line;
  33                 if (ut->ut_type != USER_PROCESS)
  34                         continue;
  35                 line = concat_path_file("/dev", ut->ut_line);
  36                 xopen_xwrite_close(line, msg);
  37                 free(line);
  38         }
  39         if (ENABLE_FEATURE_CLEAN_UP) {
  40                 endutent();
  41                 free(msg);
  42         }
  43         return EXIT_SUCCESS;
  44 }