linux: Split tst-ttyname

The tst-ttyname-direct.c checks the ttyname with procfs mounted in
bind mode (MS_BIND|MS_REC), while tst-ttyname-namespace.c checks
with procfs mount with MS_NOSUID|MS_NOEXEC|MS_NODEV in a new
namespace.

Checked on x86_64-linux-gnu and aarch64-linux-gnu.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

1 files changed, 143 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/tst-ttyname-namespace.c b/sysdeps/unix/sysv/linux/tst-ttyname-namespace.c
new file mode 100644
index 0000000..1f38442
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tst-ttyname-namespace.c
@@ -0,0 +1,143 @@
+/* Tests for ttyname/ttyname_r with namespaces.
+   Copyright (C) 2017-2023 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If
+   not, see <https://www.gnu.org/licenses/>.  */
+
+#include <sched.h>
+#include <sys/prctl.h>
+#include <sys/wait.h>
+
+#include <support/namespace.h>
+
+#include "tst-ttyname-common.c"
+
+static int
+do_in_chroot_2 (int (*cb)(const char *, int))
+{
+  printf ("info:  entering chroot 2\n");
+
+  int pid_pipe[2];
+  xpipe (pid_pipe);
+  int exit_pipe[2];
+  xpipe (exit_pipe);
+
+  /* Open the PTS that we'll be testing on.  */
+  int master;
+  char *slavename;
+  VERIFY ((master = posix_openpt (O_RDWR|O_NOCTTY|O_NONBLOCK)) >= 0);
+  VERIFY ((slavename = ptsname (master)));
+  VERIFY (unlockpt (master) == 0);
+  if (strncmp (slavename, "/dev/pts/", 9) != 0)
+    FAIL_UNSUPPORTED ("slave pseudo-terminal is not under /dev/pts/: %s",
+                      slavename);
+  adjust_file_limit (slavename);
+  /* wait until in a new mount ns to open the slave */
+
+  /* enable `wait`ing on grandchildren */
+  VERIFY (prctl (PR_SET_CHILD_SUBREAPER, 1) == 0);
+
+  pid_t pid = xfork (); /* outer child */
+  if (pid == 0)
+    {
+      xclose (master);
+      xclose (pid_pipe[0]);
+      xclose (exit_pipe[1]);
+
+      if (!support_enter_mount_namespace ())
+	FAIL_UNSUPPORTED ("could not enter new mount namespace");
+
+      int slave = xopen (slavename, O_RDWR, 0);
+      if (!doit (slave, "basic smoketest",
+                 (struct result_r){.name=slavename, .ret=0, .err=0}))
+        _exit (1);
+
+      VERIFY (mount ("tmpfs", chrootdir, "tmpfs", 0, "mode=755") == 0);
+      VERIFY (chdir (chrootdir) == 0);
+
+      xmkdir ("proc", 0755);
+      xmkdir ("dev", 0755);
+      xmkdir ("dev/pts", 0755);
+
+      VERIFY (mount ("devpts", "dev/pts", "devpts",
+                     MS_NOSUID|MS_NOEXEC,
+                     "newinstance,ptmxmode=0666,mode=620") == 0);
+      VERIFY (symlink ("pts/ptmx", "dev/ptmx") == 0);
+
+      touch ("console", 0);
+      touch ("dev/console", 0);
+      VERIFY (mount (slavename, "console", NULL, MS_BIND, NULL) == 0);
+
+      xchroot (".");
+
+      if (unshare (CLONE_NEWNS | CLONE_NEWPID) < 0)
+        FAIL_UNSUPPORTED ("could not enter new PID namespace");
+      pid = xfork (); /* inner child */
+      if (pid == 0)
+        {
+          xclose (pid_pipe[1]);
+
+          /* wait until the outer child has exited */
+          char c;
+          VERIFY (read (exit_pipe[0], &c, 1) == 0);
+          xclose (exit_pipe[0]);
+
+          VERIFY (mount ("proc", "/proc", "proc",
+                         MS_NOSUID|MS_NOEXEC|MS_NODEV, NULL) == 0);
+
+          char *linkname = xasprintf ("/proc/self/fd/%d", slave);
+          char *target = proc_fd_readlink (linkname);
+          VERIFY (strcmp (target, strrchr (slavename, '/')) == 0);
+          free (linkname);
+
+          _exit (cb (slavename, slave));
+        }
+      xwrite (pid_pipe[1], &pid, sizeof pid);
+      _exit (0);
+    }
+  xclose (pid_pipe[1]);
+  xclose (exit_pipe[0]);
+  xclose (exit_pipe[1]);
+
+  /* wait for the outer child */
+  int status;
+  xwaitpid (pid, &status, 0);
+  VERIFY (WIFEXITED (status));
+  int ret = WEXITSTATUS (status);
+  if (ret != 0)
+    return ret;
+
+  /* set 'pid' to the inner child */
+  VERIFY (read (pid_pipe[0], &pid, sizeof pid) == sizeof pid);
+  xclose (pid_pipe[0]);
+
+  /* wait for the inner child */
+  xwaitpid (pid, &status, 0);
+  VERIFY (WIFEXITED (status));
+  xclose (master);
+  return WEXITSTATUS (status);
+}
+
+static int
+do_test (void)
+{
+  support_become_root ();
+
+  do_in_chroot_2 (run_chroot_tests);
+
+  return 0;
+}
+
+#include <support/test-driver.c>