sysdeps/unix/sysv/linux/tst-ttyname-namespace.c

   1 /* Tests for ttyname/ttyname_r with namespaces.
   2    Copyright (C) 2017-2024 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>