login-utils/nologin.c

   1 /*
   2  * Copyright (C) 2013 Karel Zak <kzak@redhat.com>
   3  */
   4
   5 #include <stdio.h>
   6 #include <sys/stat.h>
   7 #include <sys/types.h>
   8 #include <fcntl.h>
   9 #include <string.h>
  10 #include <unistd.h>
  11 #include <stdlib.h>
  12 #include <getopt.h>
  13
  14 #include "c.h"
  15 #include "nls.h"
  16 #include "pathnames.h"
  17
  18 /*
  19  * Always return EXIT_FAILURE (1), don't try to be smart!
  20  */
  21
  22 static void __attribute__((__noreturn__)) usage(void)
  23 {
  24         FILE *out = stdout;
  25         fputs(USAGE_HEADER, out);
  26         fprintf(out,
  27                 _(" %s [options]\n"), program_invocation_short_name);
  28
  29         fputs(USAGE_SEPARATOR, out);
  30         fputs(_("Politely refuse a login.\n"), out);
  31
  32         fputs(USAGE_OPTIONS, out);
  33         printf(USAGE_HELP_OPTIONS(16));
  34
  35         printf(USAGE_MAN_TAIL("nologin(8)"));
  36         exit(EXIT_FAILURE);
  37 }
  38
  39 int main(int argc, char *argv[])
  40 {
  41         int c, fd = -1;
  42         struct stat st;
  43         static const struct option longopts[] = {
  44                 { "help",    0, NULL, 'h' },
  45                 { "version", 0, NULL, 'V' },
  46                 { NULL, 0, NULL, 0 }
  47         };
  48
  49         setlocale(LC_ALL, "");
  50         bindtextdomain(PACKAGE, LOCALEDIR);
  51         textdomain(PACKAGE);
  52
  53         while ((c = getopt_long(argc, argv, "hV", longopts, NULL)) != -1) {
  54                 switch (c) {
  55                 case 'h':
  56                         usage();
  57                 case 'V':
  58                         print_version(EXIT_FAILURE);    /* yes FAILURE! */
  59                 default:
  60                         errtryhelp(EXIT_FAILURE);
  61                 }
  62         }
  63
  64         fd = open(_PATH_NOLOGIN_TXT, O_RDONLY);
  65         if (fd < 0)
  66                 goto dflt;
  67
  68         c = fstat(fd, &st);
  69         if (c < 0 || !S_ISREG(st.st_mode))
  70                 goto dflt;
  71         else {
  72                 char buf[BUFSIZ];
  73                 ssize_t rd;
  74
  75                 while ((rd = read(fd, buf, sizeof(buf))) > 0)
  76                         ignore_result( write(STDOUT_FILENO, buf, rd) );
  77
  78                 close(fd);
  79                 return EXIT_FAILURE;
  80         }
  81
  82 dflt:
  83         if (fd >= 0)
  84                 close(fd);
  85         fprintf(stdout, _("This account is currently not available.\n"));
  86         return EXIT_FAILURE;
  87 }