Re: [PATCH] linux: Split tst-ttyname

[Carlos O'Donell <carlos@redhat.com>]

On 6/1/23 13:44, Adhemerval Zanella via Libc-alpha wrote:
> The tst-ttyname may fail in container environments while trying to
> mount the procfs after the unshare (test do_in_chroot_2).  It is not
> clear why exaclty kernel returns EPERM in this case, the container
> does have CAP_SYS_CHROOT, SELinux/AppArmor is disabled, and there is
> no seccomp filter.

I was seeing this also in our Fedora Rawhide CI/CD weekly integration.

It is not a kernel issue IMO, but a system issue since I was using systemd-nspawn.

Are you using systemd-nspawn?

Zbignew just bisected this for me here:
https://bugzilla.redhat.com/show_bug.cgi?id=2210335
https://github.com/systemd/systemd/commit/57c10a5650f6bb7180f3bec31a3f24239a81be39

> To avoid always reporting the test as FAIL in such scenario, the
> test that uses new namespaces is moved to a new one and the failure
> on the mount command is now report as UNSUPPORTED.
> 
> Checked on x86_64-linux-gnu and aarch64-linux-gnu.
> ---
>  sysdeps/unix/sysv/linux/Makefile              |   1 +
>  sysdeps/unix/sysv/linux/tst-ttyname-common.c  | 416 ++++++++++++++
>  .../unix/sysv/linux/tst-ttyname-namespace.c   | 147 +++++
>  sysdeps/unix/sysv/linux/tst-ttyname.c         | 512 +-----------------
>  4 files changed, 567 insertions(+), 509 deletions(-)
>  create mode 100644 sysdeps/unix/sysv/linux/tst-ttyname-common.c
>  create mode 100644 sysdeps/unix/sysv/linux/tst-ttyname-namespace.c
> 
> diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
> index 594a5dc53e..61b9e4bef0 100644
> --- a/sysdeps/unix/sysv/linux/Makefile
> +++ b/sysdeps/unix/sysv/linux/Makefile
> @@ -225,6 +225,7 @@ tests += \
>    tst-tgkill \
>    tst-timerfd \
>    tst-ttyname \
> +  tst-ttyname-namespace \
>    # tests
>  
>  # process_madvise requires CAP_SYS_ADMIN.
> diff --git a/sysdeps/unix/sysv/linux/tst-ttyname-common.c b/sysdeps/unix/sysv/linux/tst-ttyname-common.c
> new file mode 100644
> index 0000000000..3f6d8ee944
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/tst-ttyname-common.c
> @@ -0,0 +1,416 @@
> +/* Common definitions for ttyname tests.
> +   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 <dirent.h>
> +#include <errno.h>
> +#include <fcntl.h>
> +#include <limits.h>
> +#include <stdbool.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <sys/mount.h>
> +#include <sys/resource.h>
> +#include <sys/stat.h>
> +#include <unistd.h>
> +
> +#include <support/check.h>
> +#include <support/support.h>
> +#include <support/temp_file.h>
> +#include <support/test-driver.h>
> +#include <support/xunistd.h>
> +
> +/* generic utilities */
> +
> +#define VERIFY(expr)                                                    \
> +  do {                                                                  \
> +    if (!(expr))                                                        \
> +      {                                                                 \
> +        printf ("error: %s:%d: %s: %m\n",                               \
> +                __FILE__, __LINE__, #expr);                             \
> +        exit (1);                                                       \
> +      }                                                                 \
> +  } while (0)
> +
> +static void
> +touch (const char *path, mode_t mode)
> +{
> +  xclose (xopen (path, O_WRONLY|O_CREAT|O_NOCTTY, mode));
> +}
> +
> +static size_t
> +trim_prefix (char *str, size_t str_len, const char *prefix)
> +{
> +  size_t prefix_len = strlen (prefix);
> +  if (str_len > prefix_len && memcmp (str, prefix, prefix_len) == 0)
> +    {
> +      memmove (str, str + prefix_len, str_len - prefix_len);
> +      return str_len - prefix_len;
> +    }
> +  return str_len;
> +}
> +
> +/* returns a pointer to static storage */
> +static char *
> +proc_fd_readlink (const char *linkname)
> +{
> +  static char target[PATH_MAX+1];
> +  ssize_t target_len = readlink (linkname, target, PATH_MAX);
> +  VERIFY (target_len > 0);
> +  target_len = trim_prefix (target, target_len, "(unreachable)");
> +  target[target_len] = '\0';
> +  return target;
> +}
> +
> +/* plain ttyname runner */
> +
> +struct result
> +{
> +  const char *name;
> +  int err;
> +};
> +
> +/* strings in result structure are in static storage */
> +static struct result
> +run_ttyname (int fd)
> +{
> +  struct result ret;
> +  errno = 0;
> +  ret.name = ttyname (fd);
> +  ret.err = errno;
> +  return ret;
> +}
> +
> +static bool
> +eq_ttyname (struct result actual, struct result expected)
> +{
> +  char *actual_name, *expected_name;
> +
> +  if ((actual.err == expected.err)
> +      && (!actual.name == !expected.name)
> +      && (actual.name ? strcmp (actual.name, expected.name) == 0 : true))
> +    {
> +      if (expected.name)
> +        expected_name = xasprintf ("\"%s\"", expected.name);
> +      else
> +	expected_name = xstrdup ("NULL");
> +
> +      printf ("info:      ttyname: PASS {name=%s, errno=%d}\n",
> +	      expected_name, expected.err);
> +
> +      free (expected_name);
> +      return true;
> +    }
> +
> +  if (actual.name)
> +    actual_name = xasprintf ("\"%s\"", actual.name);
> +  else
> +    actual_name = xstrdup ("NULL");
> +
> +  if (expected.name)
> +    expected_name = xasprintf ("\"%s\"", expected.name);
> +  else
> +    expected_name = xstrdup ("NULL");
> +
> +  printf ("error:     ttyname: actual {name=%s, errno=%d} != expected {name=%s, errno=%d}\n",
> +	  actual_name, actual.err,
> +	  expected_name, expected.err);
> +
> +  free (actual_name);
> +  free (expected_name);
> +  return false;
> +}
> +
> +/* ttyname_r runner */
> +
> +struct result_r
> +{
> +  const char *name;
> +  int ret;
> +  int err;
> +};
> +
> +/* strings in result structure are in static storage */
> +static struct result_r
> +run_ttyname_r (int fd)
> +{
> +  static char buf[TTY_NAME_MAX];
> +
> +  struct result_r ret;
> +  errno = 0;
> +  ret.ret = ttyname_r (fd, buf, TTY_NAME_MAX);
> +  ret.err = errno;
> +  if (ret.ret == 0)
> +    ret.name = buf;
> +  else
> +    ret.name = NULL;
> +  return ret;
> +}
> +
> +static bool
> +eq_ttyname_r (struct result_r actual, struct result_r expected)
> +{
> +  char *actual_name, *expected_name;
> +
> +  if ((actual.err == expected.err)
> +      && (actual.ret == expected.ret)
> +      && (!actual.name == !expected.name)
> +      && (actual.name ? strcmp (actual.name, expected.name) == 0 : true))
> +    {
> +      if (expected.name)
> +        expected_name = xasprintf ("\"%s\"", expected.name);
> +      else
> +        expected_name = xstrdup ("NULL");
> +
> +      printf ("info:      ttyname_r: PASS {name=%s, ret=%d, errno=%d}\n",
> +              expected_name, expected.ret, expected.err);
> +
> +      free (expected_name);
> +      return true;
> +    }
> +
> +  if (actual.name)
> +    actual_name = xasprintf ("\"%s\"", actual.name);
> +  else
> +    actual_name = xstrdup ("NULL");
> +
> +  if (expected.name)
> +    expected_name = xasprintf ("\"%s\"", expected.name);
> +  else
> +    expected_name = xstrdup ("NULL");
> +
> +  printf ("error:     ttyname_r: actual {name=%s, ret=%d, errno=%d} != expected {name=%s, ret=%d, errno=%d}\n",
> +	  actual_name, actual.ret, actual.err,
> +	  expected_name, expected.ret, expected.err);
> +
> +  free (actual_name);
> +  free (expected_name);
> +  return false;
> +}
> +
> +/* combined runner */
> +
> +static bool
> +doit (int fd, const char *testname, struct result_r expected_r)
> +{
> +  struct result expected = {.name=expected_r.name, .err=expected_r.ret};
> +  bool ret = true;
> +
> +  printf ("info:    testcase: %s\n", testname);
> +
> +  if (!eq_ttyname (run_ttyname (fd), expected))
> +    ret = false;
> +  if (!eq_ttyname_r (run_ttyname_r (fd), expected_r))
> +    ret = false;
> +
> +  if (!ret)
> +    support_record_failure ();
> +
> +  return ret;
> +}
> +
> +/* chroot setup */
> +
> +static char *chrootdir;
> +
> +static void
> +prepare (int argc, char **argv)
> +{
> +  chrootdir = xasprintf ("%s/tst-ttyname-XXXXXX", test_dir);
> +  if (mkdtemp (chrootdir) == NULL)
> +    FAIL_EXIT1 ("mkdtemp (\"%s\"): %m", chrootdir);
> +  add_temp_file (chrootdir);
> +}
> +#define PREPARE prepare
> +
> +/* Adjust the file limit so that we have a chance to open PTY.  */
> +static void
> +adjust_file_limit (const char *pty)
> +{
> +  int number = -1;
> +  if (sscanf (pty, "/dev/pts/%d", &number) != 1 || number < 0)
> +    FAIL_EXIT1 ("invalid PTY name: \"%s\"", pty);
> +
> +  /* Add a few additional descriptors to cover standard I/O streams
> +     etc.  */
> +  rlim_t desired_limit = number + 10;
> +
> +  struct rlimit lim;
> +  if (getrlimit (RLIMIT_NOFILE, &lim) != 0)
> +    FAIL_EXIT1 ("getrlimit (RLIMIT_NOFILE): %m");
> +  if (lim.rlim_cur < desired_limit)
> +    {
> +      printf ("info: adjusting RLIMIT_NOFILE from %llu to %llu\n",
> +	      (unsigned long long int) lim.rlim_cur,
> +	      (unsigned long long int) desired_limit);
> +      lim.rlim_cur = desired_limit;
> +      if (setrlimit (RLIMIT_NOFILE, &lim) != 0)
> +	printf ("warning: setrlimit (RLIMIT_NOFILE) failed: %m\n");
> +    }
> +}
> +
> +/* main test */
> +
> +static int
> +run_chroot_tests (const char *slavename, int slave)
> +{
> +  struct stat st;
> +  bool ok = true;
> +
> +  /* There are 3 groups of tests here.  The first group fairly
> +     generically does things known to mess up ttyname, and verifies
> +     that ttyname copes correctly.  The remaining groups are
> +     increasingly convoluted, as we target specific parts of ttyname
> +     to try to confuse.  */
> +
> +  /* Basic tests that it doesn't get confused by multiple devpts
> +     instances.  */
> +  {
> +    VERIFY (stat (slavename, &st) < 0); /* sanity check */
> +    if (!doit (slave, "no conflict, no match",
> +               (struct result_r){.name=NULL, .ret=ENODEV, .err=ENODEV}))
> +      ok = false;
> +    VERIFY (mount ("/console", "/dev/console", NULL, MS_BIND, NULL) == 0);
> +    if (!doit (slave, "no conflict, console",
> +               (struct result_r){.name="/dev/console", .ret=0, .err=0}))
> +      ok = false;
> +    VERIFY (umount ("/dev/console") == 0);
> +
> +    /* Keep creating PTYs until we we get a name collision.  */
> +    while (true)
> +      {
> +	if (stat (slavename, &st) == 0)
> +	  break;
> +	if (posix_openpt (O_RDWR|O_NOCTTY|O_NONBLOCK) < 0)
> +	  {
> +	    if (errno == ENOSPC || errno == EMFILE || errno == ENFILE)
> +	      FAIL_UNSUPPORTED ("cannot re-create PTY \"%s\" in chroot: %m"
> +				" (consider increasing limits)", slavename);
> +	    else
> +	      FAIL_EXIT1 ("cannot re-create PTY \"%s\" chroot: %m", slavename);
> +	  }
> +      }
> +
> +    if (!doit (slave, "conflict, no match",
> +               (struct result_r){.name=NULL, .ret=ENODEV, .err=ENODEV}))
> +      ok = false;
> +    VERIFY (mount ("/console", "/dev/console", NULL, MS_BIND, NULL) == 0);
> +    if (!doit (slave, "conflict, console",
> +               (struct result_r){.name="/dev/console", .ret=0, .err=0}))
> +      ok = false;
> +    VERIFY (umount ("/dev/console") == 0);
> +  }
> +
> +  /* The first tests kinda assumed that they hit certain code-paths
> +     based on assuming that the readlink target is 'slavename', but
> +     that's not quite always true.  They're still a good preliminary
> +     sanity check, so keep them, but let's add tests that make sure
> +     that those code-paths are hit by doing a readlink ourself.  */
> +  {
> +    char *linkname = xasprintf ("/proc/self/fd/%d", slave);
> +    char *target = proc_fd_readlink (linkname);
> +    free (linkname);
> +    /* Depending on how we set up the chroot, the kernel may or may not
> +       trim the leading path to the target (it may give us "/6",
> +       instead of "/dev/pts/6").  We test it both ways (do_in_chroot_1
> +       and do_in_chroot_2).  This test group relies on the target
> +       existing, so guarantee that it does exist by creating it if
> +       necessary.  */
> +    if (stat (target, &st) < 0)
> +      {
> +        VERIFY (errno == ENOENT);
> +        touch (target, 0);
> +      }
> +
> +    VERIFY (mount ("/console", "/dev/console", NULL, MS_BIND, NULL) == 0);
> +    VERIFY (mount ("/console", target, NULL, MS_BIND, NULL) == 0);
> +    if (!doit (slave, "with readlink target",
> +               (struct result_r){.name=target, .ret=0, .err=0}))
> +      ok = false;
> +    VERIFY (umount (target) == 0);
> +    VERIFY (umount ("/dev/console") == 0);
> +
> +    VERIFY (mount ("/console", "/dev/console", NULL, MS_BIND, NULL) == 0);
> +    VERIFY (mount (slavename, target, NULL, MS_BIND, NULL) == 0);
> +    if (!doit (slave, "with readlink trap; fallback",
> +               (struct result_r){.name="/dev/console", .ret=0, .err=0}))
> +      ok = false;
> +    VERIFY (umount (target) == 0);
> +    VERIFY (umount ("/dev/console") == 0);
> +
> +    VERIFY (mount (slavename, target, NULL, MS_BIND, NULL) == 0);
> +    if (!doit (slave, "with readlink trap; no fallback",
> +               (struct result_r){.name=NULL, .ret=ENODEV, .err=ENODEV}))
> +      ok = false;
> +    VERIFY (umount (target) == 0);
> +  }
> +
> +  /* This test makes sure that everything still works OK if readdir
> +     finds a pseudo-match before and/or after the actual match.  Now,
> +     to do that, we need to control that readdir finds the
> +     pseudo-matches before and after the actual match; and there's no
> +     good way to control that order in absence of whitebox testing.
> +     So, just create 3 files, then use opendir/readdir to see what
> +     order they are in, and assign meaning based on that order, not by
> +     name; assigning the first to be a pseudo-match, the second to be
> +     the actual match, and the third to be a pseudo-match.  This
> +     assumes that (on tmpfs) ordering within the directory is stable
> +     in the absence of modification, which seems reasonably safe.  */
> +  {
> +    /* since we're testing the fallback search, disable the readlink
> +       happy-path */
> +    VERIFY (umount2 ("/proc", MNT_DETACH) == 0);
> +
> +    touch ("/dev/console1", 0);
> +    touch ("/dev/console2", 0);
> +    touch ("/dev/console3", 0);
> +
> +    char *c[3];
> +    int ci = 0;
> +    DIR *dirstream = opendir ("/dev");
> +    VERIFY (dirstream != NULL);
> +    struct dirent *d;
> +    while ((d = readdir (dirstream)) != NULL && ci < 3)
> +      {
> +        if (strcmp (d->d_name, "console1")
> +            && strcmp (d->d_name, "console2")
> +            && strcmp (d->d_name, "console3") )
> +          continue;
> +        c[ci++] = xasprintf ("/dev/%s", d->d_name);
> +      }
> +    VERIFY (ci == 3);
> +    VERIFY (closedir (dirstream) == 0);
> +
> +    VERIFY (mount (slavename, c[0], NULL, MS_BIND, NULL) == 0);
> +    VERIFY (mount ("/console", c[1], NULL, MS_BIND, NULL) == 0);
> +    VERIFY (mount (slavename, c[2], NULL, MS_BIND, NULL) == 0);
> +    VERIFY (umount2 ("/dev/pts", MNT_DETACH) == 0);
> +    if (!doit (slave, "with search-path trap",
> +               (struct result_r){.name=c[1], .ret=0, .err=0}))
> +      ok = false;
> +    for (int i = 0; i < 3; i++)
> +      {
> +        VERIFY (umount (c[i]) == 0);
> +        VERIFY (unlink (c[i]) == 0);
> +        free (c[i]);
> +      }
> +  }
> +
> +  return ok ? 0 : 1;
> +}
> +
> 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 0000000000..7b74258c10
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/tst-ttyname-namespace.c
> @@ -0,0 +1,147 @@
> +/* 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]);
> +
> +	  if (mount ("proc", "/proc", "proc",
> +		     MS_NOSUID|MS_NOEXEC|MS_NODEV, NULL) != 0)
> +	    {
> +	      /* This happens if we're trying to create a nested container,
> +		 like if the build is running under podman, and we lack
> +		 priviledges.  */
> +	      if (errno == EPERM)
> +		_exit (EXIT_UNSUPPORTED);
> +	      else
> +		_exit (EXIT_FAILURE);
> +	    }
> +
> +          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));
> +        }
> +
> +      int status;
> +      xwaitpid (pid, &status, 0);
> +      _exit (WEXITSTATUS (status));
> +    }
> +  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)
> +    FAIL_UNSUPPORTED ("unable to mount /proc on inner child process");
> +  xclose (master);
> +
> +  return 0;
> +}
> +
> +static int
> +do_test (void)
> +{
> +  support_become_root ();
> +
> +  do_in_chroot_2 (run_chroot_tests);
> +
> +  return 0;
> +}
> +
> +#include <support/test-driver.c>
> diff --git a/sysdeps/unix/sysv/linux/tst-ttyname.c b/sysdeps/unix/sysv/linux/tst-ttyname.c
> index ef55665fbe..04601777d6 100644
> --- a/sysdeps/unix/sysv/linux/tst-ttyname.c
> +++ b/sysdeps/unix/sysv/linux/tst-ttyname.c
> @@ -15,256 +15,12 @@
>     License along with the GNU C Library; see the file COPYING.LIB.  If
>     not, see <https://www.gnu.org/licenses/>.  */
>  
> -#include <dirent.h>
> -#include <errno.h>
> -#include <fcntl.h>
> -#include <limits.h>
>  #include <sched.h>
> -#include <stdio.h>
> -#include <stdlib.h>
> -#include <string.h>
> -#include <sys/mount.h>
>  #include <sys/prctl.h>
> -#include <sys/stat.h>
> -#include <sys/wait.h>
> -#include <sys/resource.h>
> -#include <unistd.h>
>  
> -#include <support/check.h>
>  #include <support/namespace.h>
> -#include <support/support.h>
> -#include <support/temp_file.h>
> -#include <support/test-driver.h>
> -#include <support/xunistd.h>
>  
> -/* generic utilities */
> -
> -#define VERIFY(expr)                                                    \
> -  do {                                                                  \
> -    if (!(expr))                                                        \
> -      {                                                                 \
> -        printf ("error: %s:%d: %s: %m\n",                               \
> -                __FILE__, __LINE__, #expr);                             \
> -        exit (1);                                                       \
> -      }                                                                 \
> -  } while (0)
> -
> -static void
> -touch (const char *path, mode_t mode)
> -{
> -  xclose (xopen (path, O_WRONLY|O_CREAT|O_NOCTTY, mode));
> -}
> -
> -static size_t
> -trim_prefix (char *str, size_t str_len, const char *prefix)
> -{
> -  size_t prefix_len = strlen (prefix);
> -  if (str_len > prefix_len && memcmp (str, prefix, prefix_len) == 0)
> -    {
> -      memmove (str, str + prefix_len, str_len - prefix_len);
> -      return str_len - prefix_len;
> -    }
> -  return str_len;
> -}
> -
> -/* returns a pointer to static storage */
> -static char *
> -proc_fd_readlink (const char *linkname)
> -{
> -  static char target[PATH_MAX+1];
> -  ssize_t target_len = readlink (linkname, target, PATH_MAX);
> -  VERIFY (target_len > 0);
> -  target_len = trim_prefix (target, target_len, "(unreachable)");
> -  target[target_len] = '\0';
> -  return target;
> -}
> -
> -/* plain ttyname runner */
> -
> -struct result
> -{
> -  const char *name;
> -  int err;
> -};
> -
> -/* strings in result structure are in static storage */
> -static struct result
> -run_ttyname (int fd)
> -{
> -  struct result ret;
> -  errno = 0;
> -  ret.name = ttyname (fd);
> -  ret.err = errno;
> -  return ret;
> -}
> -
> -static bool
> -eq_ttyname (struct result actual, struct result expected)
> -{
> -  char *actual_name, *expected_name;
> -
> -  if ((actual.err == expected.err)
> -      && (!actual.name == !expected.name)
> -      && (actual.name ? strcmp (actual.name, expected.name) == 0 : true))
> -    {
> -      if (expected.name)
> -        expected_name = xasprintf ("\"%s\"", expected.name);
> -      else
> -	expected_name = xstrdup ("NULL");
> -
> -      printf ("info:      ttyname: PASS {name=%s, errno=%d}\n",
> -	      expected_name, expected.err);
> -
> -      free (expected_name);
> -      return true;
> -    }
> -
> -  if (actual.name)
> -    actual_name = xasprintf ("\"%s\"", actual.name);
> -  else
> -    actual_name = xstrdup ("NULL");
> -
> -  if (expected.name)
> -    expected_name = xasprintf ("\"%s\"", expected.name);
> -  else
> -    expected_name = xstrdup ("NULL");
> -
> -  printf ("error:     ttyname: actual {name=%s, errno=%d} != expected {name=%s, errno=%d}\n",
> -	  actual_name, actual.err,
> -	  expected_name, expected.err);
> -
> -  free (actual_name);
> -  free (expected_name);
> -  return false;
> -}
> -
> -/* ttyname_r runner */
> -
> -struct result_r
> -{
> -  const char *name;
> -  int ret;
> -  int err;
> -};
> -
> -/* strings in result structure are in static storage */
> -static struct result_r
> -run_ttyname_r (int fd)
> -{
> -  static char buf[TTY_NAME_MAX];
> -
> -  struct result_r ret;
> -  errno = 0;
> -  ret.ret = ttyname_r (fd, buf, TTY_NAME_MAX);
> -  ret.err = errno;
> -  if (ret.ret == 0)
> -    ret.name = buf;
> -  else
> -    ret.name = NULL;
> -  return ret;
> -}
> -
> -static bool
> -eq_ttyname_r (struct result_r actual, struct result_r expected)
> -{
> -  char *actual_name, *expected_name;
> -
> -  if ((actual.err == expected.err)
> -      && (actual.ret == expected.ret)
> -      && (!actual.name == !expected.name)
> -      && (actual.name ? strcmp (actual.name, expected.name) == 0 : true))
> -    {
> -      if (expected.name)
> -        expected_name = xasprintf ("\"%s\"", expected.name);
> -      else
> -        expected_name = xstrdup ("NULL");
> -
> -      printf ("info:      ttyname_r: PASS {name=%s, ret=%d, errno=%d}\n",
> -              expected_name, expected.ret, expected.err);
> -
> -      free (expected_name);
> -      return true;
> -    }
> -
> -  if (actual.name)
> -    actual_name = xasprintf ("\"%s\"", actual.name);
> -  else
> -    actual_name = xstrdup ("NULL");
> -
> -  if (expected.name)
> -    expected_name = xasprintf ("\"%s\"", expected.name);
> -  else
> -    expected_name = xstrdup ("NULL");
> -
> -  printf ("error:     ttyname_r: actual {name=%s, ret=%d, errno=%d} != expected {name=%s, ret=%d, errno=%d}\n",
> -	  actual_name, actual.ret, actual.err,
> -	  expected_name, expected.ret, expected.err);
> -
> -  free (actual_name);
> -  free (expected_name);
> -  return false;
> -}
> -
> -/* combined runner */
> -
> -static bool
> -doit (int fd, const char *testname, struct result_r expected_r)
> -{
> -  struct result expected = {.name=expected_r.name, .err=expected_r.ret};
> -  bool ret = true;
> -
> -  printf ("info:    testcase: %s\n", testname);
> -
> -  if (!eq_ttyname (run_ttyname (fd), expected))
> -    ret = false;
> -  if (!eq_ttyname_r (run_ttyname_r (fd), expected_r))
> -    ret = false;
> -
> -  if (!ret)
> -    support_record_failure ();
> -
> -  return ret;
> -}
> -
> -/* chroot setup */
> -
> -static char *chrootdir;
> -
> -static void
> -prepare (int argc, char **argv)
> -{
> -  chrootdir = xasprintf ("%s/tst-ttyname-XXXXXX", test_dir);
> -  if (mkdtemp (chrootdir) == NULL)
> -    FAIL_EXIT1 ("mkdtemp (\"%s\"): %m", chrootdir);
> -  add_temp_file (chrootdir);
> -}
> -#define PREPARE prepare
> -
> -/* Adjust the file limit so that we have a chance to open PTY.  */
> -static void
> -adjust_file_limit (const char *pty)
> -{
> -  int number = -1;
> -  if (sscanf (pty, "/dev/pts/%d", &number) != 1 || number < 0)
> -    FAIL_EXIT1 ("invalid PTY name: \"%s\"", pty);
> -
> -  /* Add a few additional descriptors to cover standard I/O streams
> -     etc.  */
> -  rlim_t desired_limit = number + 10;
> -
> -  struct rlimit lim;
> -  if (getrlimit (RLIMIT_NOFILE, &lim) != 0)
> -    FAIL_EXIT1 ("getrlimit (RLIMIT_NOFILE): %m");
> -  if (lim.rlim_cur < desired_limit)
> -    {
> -      printf ("info: adjusting RLIMIT_NOFILE from %llu to %llu\n",
> -	      (unsigned long long int) lim.rlim_cur,
> -	      (unsigned long long int) desired_limit);
> -      lim.rlim_cur = desired_limit;
> -      if (setrlimit (RLIMIT_NOFILE, &lim) != 0)
> -	printf ("warning: setrlimit (RLIMIT_NOFILE) failed: %m\n");
> -    }
> -}
> +#include "tst-ttyname-common.c"
>  
>  /* These chroot setup functions put the TTY at at "/console" (where it
>     won't be found by ttyname), and create "/dev/console" as an
> @@ -341,276 +97,14 @@ do_in_chroot_1 (int (*cb)(const char *, int))
>    return WEXITSTATUS (status);
>  }
>  
> -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);
> -}
> -
> -/* main test */
> -
> -static int
> -run_chroot_tests (const char *slavename, int slave)
> -{
> -  struct stat st;
> -  bool ok = true;
> -
> -  /* There are 3 groups of tests here.  The first group fairly
> -     generically does things known to mess up ttyname, and verifies
> -     that ttyname copes correctly.  The remaining groups are
> -     increasingly convoluted, as we target specific parts of ttyname
> -     to try to confuse.  */
> -
> -  /* Basic tests that it doesn't get confused by multiple devpts
> -     instances.  */
> -  {
> -    VERIFY (stat (slavename, &st) < 0); /* sanity check */
> -    if (!doit (slave, "no conflict, no match",
> -               (struct result_r){.name=NULL, .ret=ENODEV, .err=ENODEV}))
> -      ok = false;
> -    VERIFY (mount ("/console", "/dev/console", NULL, MS_BIND, NULL) == 0);
> -    if (!doit (slave, "no conflict, console",
> -               (struct result_r){.name="/dev/console", .ret=0, .err=0}))
> -      ok = false;
> -    VERIFY (umount ("/dev/console") == 0);
> -
> -    /* Keep creating PTYs until we we get a name collision.  */
> -    while (true)
> -      {
> -	if (stat (slavename, &st) == 0)
> -	  break;
> -	if (posix_openpt (O_RDWR|O_NOCTTY|O_NONBLOCK) < 0)
> -	  {
> -	    if (errno == ENOSPC || errno == EMFILE || errno == ENFILE)
> -	      FAIL_UNSUPPORTED ("cannot re-create PTY \"%s\" in chroot: %m"
> -				" (consider increasing limits)", slavename);
> -	    else
> -	      FAIL_EXIT1 ("cannot re-create PTY \"%s\" chroot: %m", slavename);
> -	  }
> -      }
> -
> -    if (!doit (slave, "conflict, no match",
> -               (struct result_r){.name=NULL, .ret=ENODEV, .err=ENODEV}))
> -      ok = false;
> -    VERIFY (mount ("/console", "/dev/console", NULL, MS_BIND, NULL) == 0);
> -    if (!doit (slave, "conflict, console",
> -               (struct result_r){.name="/dev/console", .ret=0, .err=0}))
> -      ok = false;
> -    VERIFY (umount ("/dev/console") == 0);
> -  }
> -
> -  /* The first tests kinda assumed that they hit certain code-paths
> -     based on assuming that the readlink target is 'slavename', but
> -     that's not quite always true.  They're still a good preliminary
> -     sanity check, so keep them, but let's add tests that make sure
> -     that those code-paths are hit by doing a readlink ourself.  */
> -  {
> -    char *linkname = xasprintf ("/proc/self/fd/%d", slave);
> -    char *target = proc_fd_readlink (linkname);
> -    free (linkname);
> -    /* Depending on how we set up the chroot, the kernel may or may not
> -       trim the leading path to the target (it may give us "/6",
> -       instead of "/dev/pts/6").  We test it both ways (do_in_chroot_1
> -       and do_in_chroot_2).  This test group relies on the target
> -       existing, so guarantee that it does exist by creating it if
> -       necessary.  */
> -    if (stat (target, &st) < 0)
> -      {
> -        VERIFY (errno == ENOENT);
> -        touch (target, 0);
> -      }
> -
> -    VERIFY (mount ("/console", "/dev/console", NULL, MS_BIND, NULL) == 0);
> -    VERIFY (mount ("/console", target, NULL, MS_BIND, NULL) == 0);
> -    if (!doit (slave, "with readlink target",
> -               (struct result_r){.name=target, .ret=0, .err=0}))
> -      ok = false;
> -    VERIFY (umount (target) == 0);
> -    VERIFY (umount ("/dev/console") == 0);
> -
> -    VERIFY (mount ("/console", "/dev/console", NULL, MS_BIND, NULL) == 0);
> -    VERIFY (mount (slavename, target, NULL, MS_BIND, NULL) == 0);
> -    if (!doit (slave, "with readlink trap; fallback",
> -               (struct result_r){.name="/dev/console", .ret=0, .err=0}))
> -      ok = false;
> -    VERIFY (umount (target) == 0);
> -    VERIFY (umount ("/dev/console") == 0);
> -
> -    VERIFY (mount (slavename, target, NULL, MS_BIND, NULL) == 0);
> -    if (!doit (slave, "with readlink trap; no fallback",
> -               (struct result_r){.name=NULL, .ret=ENODEV, .err=ENODEV}))
> -      ok = false;
> -    VERIFY (umount (target) == 0);
> -  }
> -
> -  /* This test makes sure that everything still works OK if readdir
> -     finds a pseudo-match before and/or after the actual match.  Now,
> -     to do that, we need to control that readdir finds the
> -     pseudo-matches before and after the actual match; and there's no
> -     good way to control that order in absence of whitebox testing.
> -     So, just create 3 files, then use opendir/readdir to see what
> -     order they are in, and assign meaning based on that order, not by
> -     name; assigning the first to be a pseudo-match, the second to be
> -     the actual match, and the third to be a pseudo-match.  This
> -     assumes that (on tmpfs) ordering within the directory is stable
> -     in the absence of modification, which seems reasonably safe.  */
> -  {
> -    /* since we're testing the fallback search, disable the readlink
> -       happy-path */
> -    VERIFY (umount2 ("/proc", MNT_DETACH) == 0);
> -
> -    touch ("/dev/console1", 0);
> -    touch ("/dev/console2", 0);
> -    touch ("/dev/console3", 0);
> -
> -    char *c[3];
> -    int ci = 0;
> -    DIR *dirstream = opendir ("/dev");
> -    VERIFY (dirstream != NULL);
> -    struct dirent *d;
> -    while ((d = readdir (dirstream)) != NULL && ci < 3)
> -      {
> -        if (strcmp (d->d_name, "console1")
> -            && strcmp (d->d_name, "console2")
> -            && strcmp (d->d_name, "console3") )
> -          continue;
> -        c[ci++] = xasprintf ("/dev/%s", d->d_name);
> -      }
> -    VERIFY (ci == 3);
> -    VERIFY (closedir (dirstream) == 0);
> -
> -    VERIFY (mount (slavename, c[0], NULL, MS_BIND, NULL) == 0);
> -    VERIFY (mount ("/console", c[1], NULL, MS_BIND, NULL) == 0);
> -    VERIFY (mount (slavename, c[2], NULL, MS_BIND, NULL) == 0);
> -    VERIFY (umount2 ("/dev/pts", MNT_DETACH) == 0);
> -    if (!doit (slave, "with search-path trap",
> -               (struct result_r){.name=c[1], .ret=0, .err=0}))
> -      ok = false;
> -    for (int i = 0; i < 3; i++)
> -      {
> -        VERIFY (umount (c[i]) == 0);
> -        VERIFY (unlink (c[i]) == 0);
> -        free (c[i]);
> -      }
> -  }
> -
> -  return ok ? 0 : 1;
> -}
> -
>  static int
>  do_test (void)
>  {
>    support_become_root ();
>  
> -  int ret1 = do_in_chroot_1 (run_chroot_tests);
> -  if (ret1 == EXIT_UNSUPPORTED)
> -    return ret1;
> -
> -  int ret2 = do_in_chroot_2 (run_chroot_tests);
> -  if (ret2 == EXIT_UNSUPPORTED)
> -    return ret2;
> +  do_in_chroot_1 (run_chroot_tests);
>  
> -  return  ret1 | ret2;
> +  return 0;
>  }
>  
>  #include <support/test-driver.c>

-- 
Cheers,
Carlos.