1  /* Tests for ttyname/ttyname_r with namespaces.
       2     Copyright (C) 2017-2023 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 License as
       7     published by the Free Software Foundation; either version 2.1 of the
       8     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; see the file COPYING.LIB.  If
      17     not, see <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <sched.h>
      20  #include <sys/prctl.h>
      21  #include <sys/wait.h>
      22  
      23  #include <support/namespace.h>
      24  
      25  #include "tst-ttyname-common.c"
      26  
      27  static int
      28  do_in_chroot_2 (int (*cb)(const char *, int))
      29  {
      30    printf ("info:  entering chroot 2\n");
      31  
      32    int pid_pipe[2];
      33    xpipe (pid_pipe);
      34    int exit_pipe[2];
      35    xpipe (exit_pipe);
      36  
      37    /* Open the PTS that we'll be testing on.  */
      38    int master;
      39    char *slavename;
      40    VERIFY ((master = posix_openpt (O_RDWR|O_NOCTTY|O_NONBLOCK)) >= 0);
      41    VERIFY ((slavename = ptsname (master)));
      42    VERIFY (unlockpt (master) == 0);
      43    if (strncmp (slavename, "/dev/pts/", 9) != 0)
      44      FAIL_UNSUPPORTED ("slave pseudo-terminal is not under /dev/pts/: %s",
      45                        slavename);
      46    adjust_file_limit (slavename);
      47    /* wait until in a new mount ns to open the slave */
      48  
      49    /* enable `wait`ing on grandchildren */
      50    VERIFY (prctl (PR_SET_CHILD_SUBREAPER, 1) == 0);
      51  
      52    pid_t pid = xfork (); /* outer child */
      53    if (pid == 0)
      54      {
      55        xclose (master);
      56        xclose (pid_pipe[0]);
      57        xclose (exit_pipe[1]);
      58  
      59        if (!support_enter_mount_namespace ())
      60  	FAIL_UNSUPPORTED ("could not enter new mount namespace");
      61  
      62        int slave = xopen (slavename, O_RDWR, 0);
      63        if (!doit (slave, "basic smoketest",
      64                   (struct result_r){.name=slavename, .ret=0, .err=0}))
      65          _exit (1);
      66  
      67        VERIFY (mount ("tmpfs", chrootdir, "tmpfs", 0, "mode=755") == 0);
      68        VERIFY (chdir (chrootdir) == 0);
      69  
      70        xmkdir ("proc", 0755);
      71        xmkdir ("dev", 0755);
      72        xmkdir ("dev/pts", 0755);
      73  
      74        VERIFY (mount ("devpts", "dev/pts", "devpts",
      75                       MS_NOSUID|MS_NOEXEC,
      76                       "newinstance,ptmxmode=0666,mode=620") == 0);
      77        VERIFY (symlink ("pts/ptmx", "dev/ptmx") == 0);
      78  
      79        touch ("console", 0);
      80        touch ("dev/console", 0);
      81        VERIFY (mount (slavename, "console", NULL, MS_BIND, NULL) == 0);
      82  
      83        xchroot (".");
      84  
      85        if (unshare (CLONE_NEWNS | CLONE_NEWPID) < 0)
      86          FAIL_UNSUPPORTED ("could not enter new PID namespace");
      87        pid = xfork (); /* inner child */
      88        if (pid == 0)
      89          {
      90            xclose (pid_pipe[1]);
      91  
      92            /* wait until the outer child has exited */
      93            char c;
      94            VERIFY (read (exit_pipe[0], &c, 1) == 0);
      95            xclose (exit_pipe[0]);
      96  
      97  	  if (mount ("proc", "/proc", "proc",
      98  		     MS_NOSUID|MS_NOEXEC|MS_NODEV, NULL) != 0)
      99  	    {
     100  	      /* This happens if we're trying to create a nested container,
     101  		 like if the build is running under podman, and we lack
     102  		 priviledges.  */
     103  	      if (errno == EPERM)
     104  		_exit (EXIT_UNSUPPORTED);
     105  	      else
     106  		_exit (EXIT_FAILURE);
     107  	    }
     108  
     109            char *linkname = xasprintf ("/proc/self/fd/%d", slave);
     110            char *target = proc_fd_readlink (linkname);
     111            VERIFY (strcmp (target, strrchr (slavename, '/')) == 0);
     112            free (linkname);
     113  
     114            _exit (cb (slavename, slave));
     115          }
     116        int status;
     117        xwaitpid (pid, &status, 0);
     118        _exit (WEXITSTATUS (status));
     119      }
     120    xclose (pid_pipe[1]);
     121    xclose (exit_pipe[0]);
     122    xclose (exit_pipe[1]);
     123  
     124    /* wait for the outer child */
     125    int status;
     126    xwaitpid (pid, &status, 0);
     127    VERIFY (WIFEXITED (status));
     128    int ret = WEXITSTATUS (status);
     129    if (ret != 0)
     130      FAIL_UNSUPPORTED ("unable to mount /proc on inner child process");
     131  
     132    xclose (pid_pipe[0]);
     133  
     134    return 0;
     135  }
     136  
     137  static int
     138  do_test (void)
     139  {
     140    support_become_root ();
     141  
     142    do_in_chroot_2 (run_chroot_tests);
     143  
     144    return 0;
     145  }
     146  
     147  #include <support/test-driver.c>