1  /* Basic test for gethostid.
       2     Copyright (C) 2018-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <gnu/lib-names.h>
      20  #include <nss.h>
      21  #include <stdio.h>
      22  #include <stdlib.h>
      23  #include <string.h>
      24  #include <support/namespace.h>
      25  #include <support/support.h>
      26  #include <support/temp_file.h>
      27  #include <support/xdlfcn.h>
      28  #include <support/xstdio.h>
      29  #include <support/xunistd.h>
      30  #include <unistd.h>
      31  
      32  /* Initial test is run outside a chroot, to increase the likelihood of
      33     success.  */
      34  static void
      35  outside_chroot (void *closure)
      36  {
      37    long id = gethostid ();
      38    printf ("info: host ID outside chroot: 0x%lx\n", id);
      39  }
      40  
      41  /* The same, but this time perform a chroot operation.  */
      42  static void
      43  in_chroot (void *closure)
      44  {
      45    const char *chroot_path = closure;
      46    xchroot (chroot_path);
      47    long id = gethostid ();
      48    printf ("info: host ID in chroot: 0x%lx\n", id);
      49  }
      50  
      51  static int
      52  do_test (void)
      53  {
      54    support_isolate_in_subprocess (outside_chroot, NULL);
      55  
      56    /* Now run the test inside a chroot.  */
      57    support_become_root ();
      58    if (!support_can_chroot ())
      59      /* Cannot perform further tests.  */
      60      return 0;
      61  
      62    /* Only use nss_files.  */
      63    __nss_configure_lookup ("hosts", "files");
      64  
      65    /* Load the DSO outside of the chroot.  */
      66    xdlopen (LIBNSS_FILES_SO, RTLD_LAZY);
      67  
      68    char *chroot_dir = support_create_temp_directory ("tst-gethostid-");
      69    support_isolate_in_subprocess (in_chroot, chroot_dir);
      70  
      71    /* Tests with /etc/hosts in the chroot.  */
      72    {
      73      char *path = xasprintf ("%s/etc", chroot_dir);
      74      add_temp_file (path);
      75      xmkdir (path, 0777);
      76      free (path);
      77      path = xasprintf ("%s/etc/hosts", chroot_dir);
      78      add_temp_file (path);
      79  
      80      FILE *fp = xfopen (path, "w");
      81      xfclose (fp);
      82      printf ("info: chroot test with an empty /etc/hosts file\n");
      83      support_isolate_in_subprocess (in_chroot, chroot_dir);
      84  
      85      char hostname[1024];
      86      int ret = gethostname (hostname, sizeof (hostname));
      87      if (ret < 0)
      88        printf ("warning: invalid result from gethostname: %d\n", ret);
      89      else if (strlen (hostname) == 0)
      90        puts ("warning: gethostname returned empty string");
      91      else
      92        {
      93          printf ("info: chroot test with IPv6 address in /etc/hosts for: %s\n",
      94                  hostname);
      95          fp = xfopen (path, "w");
      96          /* Use an IPv6 address to induce another lookup failure.  */
      97          fprintf (fp, "2001:db8::1 %s\n", hostname);
      98          xfclose (fp);
      99          support_isolate_in_subprocess (in_chroot, chroot_dir);
     100        }
     101      free (path);
     102    }
     103    free (chroot_dir);
     104  
     105    return 0;
     106  }
     107  
     108  #include <support/test-driver.c>