commit 341da5b4b6253de9a7581a066f33f89cacb44dec

Author: Florian Weimer <fweimer@redhat.com>

Date:   Thu Aug 15 10:30:23 2019 +0200

    login: Fix updwtmp, updwtmx unlocking

    Commit 5a3afa9738f3dbbaf8c0a35665318c1af782111b (login: Replace

    macro-based control flow with function calls in utmp) introduced

    a regression because after it, __libc_updwtmp attempts to unlock

    the wrong file descriptor.

diff --git a/login/Makefile b/login/Makefile

index 8b31991be835fa8e..81986ab6bd8560ea 100644

--- a/login/Makefile

+++ b/login/Makefile

@@ -43,7 +43,7 @@ endif

 subdir-dirs = programs

 vpath %.c programs

-tests := tst-utmp tst-utmpx tst-grantpt tst-ptsname tst-getlogin

+tests := tst-utmp tst-utmpx tst-grantpt tst-ptsname tst-getlogin tst-updwtmpx

 # Build the -lutil library with these extra functions.

 extra-libs      := libutil

diff --git a/login/tst-updwtmpx.c b/login/tst-updwtmpx.c

new file mode 100644

index 0000000000000000..0a4a27daeb0440fd

--- /dev/null

+++ b/login/tst-updwtmpx.c

@@ -0,0 +1,112 @@

+/* Basic test coverage for updwtmpx.

+   Copyright (C) 2019 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 <http://www.gnu.org/licenses/>.  */

+

+/* This program runs a series of tests.  Each one calls updwtmpx

+   twice, to write two records, optionally with misalignment in the

+   file, and reads back the results.  */

+

+#include <errno.h>

+#include <stdlib.h>

+#include <support/check.h>

+#include <support/descriptors.h>

+#include <support/support.h>

+#include <support/temp_file.h>

+#include <support/test-driver.h>

+#include <support/xunistd.h>

+#include <unistd.h>

+#include <utmpx.h>

+

+static int

+do_test (void)

+{

+  /* Two entries filled with an arbitrary bit pattern.  */

+  struct utmpx entries[2];

+  unsigned char pad;

+  {

+    unsigned char *p = (unsigned char *) &entries[0];

+    for (size_t i = 0; i < sizeof (entries); ++i)

+      {

+        p[i] = i;

+      }

+    /* Make sure that the first and second entry and the padding are

+       different.  */

+    p[sizeof (struct utmpx)] = p[0] + 1;

+    pad = p[0] + 2;

+  }

+

+  char *path;

+  int fd = create_temp_file ("tst-updwtmpx-", &path);

+

+  /* Used to check that updwtmpx does not leave an open file

+     descriptor around.  */

+  struct support_descriptors *descriptors = support_descriptors_list ();

+

+  /* updwtmpx is expected to remove misalignment.  Optionally insert

+     one byte of misalignment at the start and in the middle (after

+     the first entry).  */

+  for (int misaligned_start = 0; misaligned_start < 2; ++misaligned_start)

+    for (int misaligned_middle = 0; misaligned_middle < 2; ++misaligned_middle)

+      {

+        if (test_verbose > 0)

+          printf ("info: misaligned_start=%d misaligned_middle=%d\n",

+                  misaligned_start, misaligned_middle);

+

+        xftruncate (fd, 0);

+        TEST_COMPARE (pwrite64 (fd, &pad, misaligned_start, 0),

+                      misaligned_start);

+

+        /* Write first entry and check it.  */

+        errno = 0;

+        updwtmpx (path, &entries[0]);

+        TEST_COMPARE (errno, 0);

+        support_descriptors_check (descriptors);

+        TEST_COMPARE (xlseek (fd, 0, SEEK_END), sizeof (struct utmpx));

+        struct utmpx buffer;

+        TEST_COMPARE (pread64 (fd, &buffer, sizeof (buffer), 0),

+                      sizeof (buffer));

+        TEST_COMPARE_BLOB (&entries[0], sizeof (entries[0]),

+                           &buffer, sizeof (buffer));

+

+        /* Middle mis-alignmet.  */

+        TEST_COMPARE (pwrite64 (fd, &pad, misaligned_middle,

+                                sizeof (struct utmpx)), misaligned_middle);

+

+        /* Write second entry and check both entries.  */

+        errno = 0;

+        updwtmpx (path, &entries[1]);

+        TEST_COMPARE (errno, 0);

+        support_descriptors_check (descriptors);

+        TEST_COMPARE (xlseek (fd, 0, SEEK_END), 2 * sizeof (struct utmpx));

+        TEST_COMPARE (pread64 (fd, &buffer, sizeof (buffer), 0),

+                      sizeof (buffer));

+        TEST_COMPARE_BLOB (&entries[0], sizeof (entries[0]),

+                           &buffer, sizeof (buffer));

+        TEST_COMPARE (pread64 (fd, &buffer, sizeof (buffer), sizeof (buffer)),

+                      sizeof (buffer));

+        TEST_COMPARE_BLOB (&entries[1], sizeof (entries[1]),

+                           &buffer, sizeof (buffer));

+      }

+

+  support_descriptors_free (descriptors);

+  free (path);

+  xclose (fd);

+

+  return 0;

+}

+

+#include <support/test-driver.c>

diff --git a/login/utmp_file.c b/login/utmp_file.c

index 812de8fd3d099ce9..54f424fd6165bae7 100644

--- a/login/utmp_file.c

+++ b/login/utmp_file.c

@@ -503,7 +503,7 @@ __libc_updwtmp (const char *file, const struct utmp *utmp)

   result = 0;

 unlock_return:

-  file_unlock (file_fd);

+  file_unlock (fd);

   file_lock_restore (&fl);

   /* Close WTMP file.  */