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         fputs(USAGE_HELP, out);
  34         fputs(USAGE_VERSION, out);
  35
  36         fprintf(out, USAGE_MAN_TAIL("nologin(8)"));
  37         exit(EXIT_FAILURE);
  38 }
  39
  40 int main(int argc, char *argv[])
  41 {
  42         int c, fd = -1;
  43         struct stat st;
  44         static const struct option longopts[] = {
  45                 { "help",    0, NULL, 'h' },
  46                 { "version", 0, NULL, 'V' },
  47                 { NULL, 0, NULL, 0 }
  48         };
  49
  50         setlocale(LC_ALL, "");
  51         bindtextdomain(PACKAGE, LOCALEDIR);
  52         textdomain(PACKAGE);
  53
  54         while ((c = getopt_long(argc, argv, "hV", longopts, NULL)) != -1) {
  55                 switch (c) {
  56                 case 'h':
  57                         usage();
  58                         break;
  59                 case 'V':
  60                         printf(UTIL_LINUX_VERSION);
  61                         return EXIT_FAILURE;
  62                 default:
  63                         errtryhelp(EXIT_FAILURE);
  64                 }
  65         }
  66
  67         fd = open(_PATH_NOLOGIN_TXT, O_RDONLY);
  68         if (fd < 0)
  69                 goto dflt;
  70
  71         c = fstat(fd, &st);
  72         if (c < 0 || !S_ISREG(st.st_mode))
  73                 goto dflt;
  74         else {
  75                 char buf[BUFSIZ];
  76                 ssize_t rd;
  77
  78                 while ((rd = read(fd, buf, sizeof(buf))) > 0)
  79                         ignore_result( write(STDOUT_FILENO, buf, rd) );
  80
  81                 close(fd);
  82                 return EXIT_FAILURE;
  83         }
  84
  85 dflt:
  86         if (fd >= 0)
  87                 close(fd);
  88         fprintf(stdout, _("This account is currently not available.\n"));
  89         return EXIT_FAILURE;
  90 }