Backport only the test case:

 * sysdeps/unix/sysv/linux/tst-sysvmsg-linux.c

This improves coverage for IPC_INFO and MSG_INFO.

We don't need the actual fix in the bug because we don't have the 64-bit

time_t handling backported.

commit 20a00dbefca5695cccaa44846a482db8ccdd85ab

Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>

Date:   Tue Sep 29 14:39:56 2020 -0300

    sysvipc: Fix IPC_INFO and MSG_INFO handling [BZ #26639]

    Both commands are Linux extensions where the third argument is a

    'struct msginfo' instead of 'struct msqid_ds' and its information

    does not contain any time related fields (so there is no need to

    extra conversion for __IPC_TIME64.

    The regression testcase checks for Linux specifix SysV ipc message

    control extension.  For IPC_INFO/MSG_INFO it tries to match the values

    against the tunable /proc values and for MSG_STAT/MSG_STAT_ANY it

    check if the create message queue is within the global list returned

    by the kernel.

    Checked on x86_64-linux-gnu and on i686-linux-gnu (Linux v5.4 and on

    Linux v4.15).

diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile

index 7d04e3313c56c15d..688cf9fa9dea23a6 100644

--- a/sysdeps/unix/sysv/linux/Makefile

+++ b/sysdeps/unix/sysv/linux/Makefile

@@ -46,7 +46,7 @@ tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \

 	 tst-quota tst-sync_file_range tst-sysconf-iov_max tst-ttyname \

 	 test-errno-linux tst-memfd_create tst-mlock2 tst-pkey \

 	 tst-rlimit-infinity tst-ofdlocks \

-	 tst-sysvsem-linux

+	 tst-sysvsem-linux tst-sysvmsg-linux

 tests-internal += tst-ofdlocks-compat

diff --git a/sysdeps/unix/sysv/linux/tst-sysvmsg-linux.c b/sysdeps/unix/sysv/linux/tst-sysvmsg-linux.c

new file mode 100644

index 0000000000000000..1857fab8c1fdf041

--- /dev/null

+++ b/sysdeps/unix/sysv/linux/tst-sysvmsg-linux.c

@@ -0,0 +1,177 @@

+/* Basic tests for Linux SYSV message queue extensions.

+   Copyright (C) 2020-2021 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; if not, see

+   <https://www.gnu.org/licenses/>.  */

+

+#include <sys/ipc.h>

+#include <sys/msg.h>

+#include <errno.h>

+#include <stdlib.h>

+#include <stdbool.h>

+#include <stdio.h>

+

+#include <support/check.h>

+#include <support/temp_file.h>

+

+#define MSGQ_MODE 0644

+

+/* These are for the temporary file we generate.  */

+static char *name;

+static int msqid;

+

+static void

+remove_msq (void)

+{

+  /* Enforce message queue removal in case of early test failure.

+     Ignore error since the msg may already have being removed.  */

+  msgctl (msqid, IPC_RMID, NULL);

+}

+

+static void

+do_prepare (int argc, char *argv[])

+{

+  TEST_VERIFY_EXIT (create_temp_file ("tst-sysvmsg.", &name) != -1);

+}

+

+#define PREPARE do_prepare

+

+struct test_msginfo

+{

+  int msgmax;

+  int msgmnb;

+  int msgmni;

+};

+

+/* It tries to obtain some system-wide SysV messsage queue information from

+   /proc to check against IPC_INFO/MSG_INFO.  The /proc only returns the

+   tunables value of MSGMAX, MSGMNB, and MSGMNI.

+

+   The kernel also returns constant value for MSGSSZ, MSGSEG and also MSGMAP,

+   MSGPOOL, and MSGTQL (for IPC_INFO).  The issue to check them is they might

+   change over kernel releases.  */

+

+static int

+read_proc_file (const char *file)

+{

+  FILE *f = fopen (file, "r");

+  if (f == NULL)

+    FAIL_UNSUPPORTED ("/proc is not mounted or %s is not available", file);

+

+  int v;

+  int r = fscanf (f, "%d", & v);

+  TEST_VERIFY_EXIT (r == 1);

+

+  fclose (f);

+  return v;

+}

+

+

+/* Check if the message queue with IDX (index into the kernel's internal

+   array) matches the one with KEY.  The CMD is either MSG_STAT or

+   MSG_STAT_ANY.  */

+

+static bool

+check_msginfo (int idx, key_t key, int cmd)

+{

+  struct msqid_ds msginfo;

+  int mid = msgctl (idx, cmd, &msginfo);

+  /* Ignore unused array slot returned by the kernel or information from

+     unknown message queue.  */

+  if ((mid == -1 && errno == EINVAL) || mid != msqid)

+    return false;

+

+  if (mid == -1)

+    FAIL_EXIT1 ("msgctl with %s failed: %m",

+		cmd == MSG_STAT ? "MSG_STAT" : "MSG_STAT_ANY");

+

+  TEST_COMPARE (msginfo.msg_perm.__key, key);

+  TEST_COMPARE (msginfo.msg_perm.mode, MSGQ_MODE);

+  TEST_COMPARE (msginfo.msg_qnum, 0);

+

+  return true;

+}

+

+static int

+do_test (void)

+{

+  atexit (remove_msq);

+

+  key_t key = ftok (name, 'G');

+  if (key == -1)

+    FAIL_EXIT1 ("ftok failed: %m");

+

+  msqid = msgget (key, MSGQ_MODE | IPC_CREAT);

+  if (msqid == -1)

+    FAIL_EXIT1 ("msgget failed: %m");

+

+  struct test_msginfo tipcinfo;

+  tipcinfo.msgmax = read_proc_file ("/proc/sys/kernel/msgmax");

+  tipcinfo.msgmnb = read_proc_file ("/proc/sys/kernel/msgmnb");

+  tipcinfo.msgmni = read_proc_file ("/proc/sys/kernel/msgmni");

+

+  int msqidx;

+

+  {

+    struct msginfo ipcinfo;

+    msqidx = msgctl (msqid, IPC_INFO, (struct msqid_ds *) &ipcinfo);

+    if (msqidx == -1)

+      FAIL_EXIT1 ("msgctl with IPC_INFO failed: %m");

+

+    TEST_COMPARE (ipcinfo.msgmax, tipcinfo.msgmax);

+    TEST_COMPARE (ipcinfo.msgmnb, tipcinfo.msgmnb);

+    TEST_COMPARE (ipcinfo.msgmni, tipcinfo.msgmni);

+  }

+

+  /* Same as before but with MSG_INFO.  */

+  {

+    struct msginfo ipcinfo;

+    msqidx = msgctl (msqid, MSG_INFO, (struct msqid_ds *) &ipcinfo);

+    if (msqidx == -1)

+      FAIL_EXIT1 ("msgctl with IPC_INFO failed: %m");

+

+    TEST_COMPARE (ipcinfo.msgmax, tipcinfo.msgmax);

+    TEST_COMPARE (ipcinfo.msgmnb, tipcinfo.msgmnb);

+    TEST_COMPARE (ipcinfo.msgmni, tipcinfo.msgmni);

+  }

+

+  /* We check if the created message queue shows in global list.  */

+  bool found = false;

+  for (int i = 0; i <= msqidx; i++)

+    {

+      /* We can't tell apart if MSG_STAT_ANY is not supported (kernel older

+	 than 4.17) or if the index used is invalid.  So it just check if the

+	 value returned from a valid call matches the created message

+	 queue.  */

+      check_msginfo (i, key, MSG_STAT_ANY);

+

+      if (check_msginfo (i, key, MSG_STAT))

+	{

+	  found = true;

+	  break;

+	}

+    }

+

+  if (!found)

+    FAIL_EXIT1 ("msgctl with MSG_STAT/MSG_STAT_ANY could not find the "

+		"created message queue");

+

+  if (msgctl (msqid, IPC_RMID, NULL) == -1)

+    FAIL_EXIT1 ("msgctl failed");

+

+  return 0;

+}

+

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