[v2] tst: Provide test for ppoll

  This change adds new test to assess ppoll()'s timeout related
functionality (the struct pollfd does not provide valid fd to wait
for - just wait for timeout).

To be more specific - two use cases are checked:
- if ppoll() times out immediately when passed struct timespec has zero
values of tv_nsec and tv_sec.
- if ppoll() times out after timeout specified in passed argument

---
Changes for v2:
- Remove _GNU_SOURCE definition if not already defined
- Replace clock_gettime with xclock_gettime
- Use FAIL_EXIT1 instead of plain ret value returning from the test
---
 sysdeps/unix/sysv/linux/Makefile    |  2 +-
 sysdeps/unix/sysv/linux/tst-ppoll.c | 62 +++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+), 1 deletion(-)
 create mode 100644 sysdeps/unix/sysv/linux/tst-ppoll.c
  

Hi Florian,

> This change adds new test to assess ppoll()'s timeout related
> functionality (the struct pollfd does not provide valid fd to wait
> for - just wait for timeout).
> 
> To be more specific - two use cases are checked:
> - if ppoll() times out immediately when passed struct timespec has
> zero values of tv_nsec and tv_sec.
> - if ppoll() times out after timeout specified in passed argument
> 

Do you have any more comments regarding this patch?

Is it eligible to be pulled to -master?

> ---
> Changes for v2:
> - Remove _GNU_SOURCE definition if not already defined
> - Replace clock_gettime with xclock_gettime
> - Use FAIL_EXIT1 instead of plain ret value returning from the test
> ---
>  sysdeps/unix/sysv/linux/Makefile    |  2 +-
>  sysdeps/unix/sysv/linux/tst-ppoll.c | 62
> +++++++++++++++++++++++++++++ 2 files changed, 63 insertions(+), 1
> deletion(-) create mode 100644 sysdeps/unix/sysv/linux/tst-ppoll.c
> 
> diff --git a/sysdeps/unix/sysv/linux/Makefile
> b/sysdeps/unix/sysv/linux/Makefile index 7503b356c8..f4029a74ca 100644
> --- a/sysdeps/unix/sysv/linux/Makefile
> +++ b/sysdeps/unix/sysv/linux/Makefile
> @@ -108,7 +108,7 @@ tests += tst-clone tst-clone2 tst-clone3
> tst-fanotify tst-personality \ test-errno-linux tst-memfd_create
> tst-mlock2 tst-pkey \ tst-rlimit-infinity tst-ofdlocks tst-gettid
> tst-gettid-kill \ tst-tgkill tst-sysvsem-linux tst-sysvmsg-linux
> tst-sysvshm-linux \
> -	 tst-timerfd
> +	 tst-timerfd tst-ppoll
>  tests-internal += tst-ofdlocks-compat tst-sigcontext-get_pc
>  
>  CFLAGS-tst-sigcontext-get_pc.c = -fasynchronous-unwind-tables
> diff --git a/sysdeps/unix/sysv/linux/tst-ppoll.c
> b/sysdeps/unix/sysv/linux/tst-ppoll.c new file mode 100644
> index 0000000000..eeff97f103
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/tst-ppoll.c
> @@ -0,0 +1,62 @@
> +/* Test for ppoll timeout
> +   Copyright (C) 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 <time.h>
> +#include <poll.h>
> +#include <support/check.h>
> +#include <support/xtime.h>
> +
> +/* Timeout in seconds for PPOLL.  */
> +#define PPOLL_TIMEOUT 2
> +/* Timeout for test program - must be larger than PPOLL_TIMEOUT.  */
> +#define TIMEOUT 3
> +
> +static int test_ppoll_timeout (int timeout)
> +{
> +  struct timespec tv0 = { 0, 0 }, tv1 = { 0, 0 }, tv = { 0, 0 };
> +  struct pollfd fds = { -1, 0, 0 };   /* Ignore fds - just wait for
> timeout.  */
> +  int ret;
> +
> +  tv.tv_sec = timeout;
> +
> +  xclock_gettime (CLOCK_REALTIME, &tv0);
> +
> +  ret = ppoll (&fds, 1, &tv, 0);
> +  if (ret != 0)
> +      FAIL_EXIT1 ("*** ppoll failed: %m\n");
> +
> +  xclock_gettime (CLOCK_REALTIME, &tv1);
> +  if (tv0.tv_sec + timeout != tv1.tv_sec)
> +      FAIL_EXIT1 ("*** ppoll failed to timeout after %d [s]\n",
> timeout); +
> +  return 0;
> +}
> +
> +static int
> +do_test (void)
> +{
> +  /* Check if ppoll exits immediately.  */
> +  test_ppoll_timeout (0);
> +
> +  /* Check if ppoll exits after specified timeout.  */
> +  test_ppoll_timeout (PPOLL_TIMEOUT);
> +
> +  return 0;
> +}
> +
> +#include <support/test-driver.c>




Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de
  

Dear Community,

Please find the list of patches necessary for providing Y2038 support
on ports with __WORDSIZE == 32 && __TIMESIZE != 64 (like e.g. armv7a).

1. The stat needs to have proper helper function exported [1].

2. The exported msqid_ds needs to be adjusted [2] and internal copy of
it is necessary [3][4].

The most up to date branch with Y2038 support [5] also includes some
new tests (also Y2038 specific for glibc).

Tests, which are going to be ported to glibc test suite, can be found
here [6]. They reuse the cross-test-ssh.sh script to run on 32 bit ARM
VM. The branch [5] also includes some enhancements for the
aforementioned script.


Links:

[1] -
https://github.com/lmajewski/y2038_glibc/commit/54318a2d434ae773786df2dda1665801ef8756b8
[2] -
https://github.com/lmajewski/y2038_glibc/commit/dc5fc16439d61b45c16a8e97c2b2bbf43f3b07b7
[3] -
https://github.com/lmajewski/y2038_glibc/commit/45fd003e9f92aa88864ad8240fc97ae150711cea
[4] -
https://github.com/lmajewski/y2038_glibc/commit/19ca132bea12a77c89e117f0850895ec0afccf18
[5] - https://github.com/lmajewski/y2038_glibc/commits/y2038_edge

[6] - https://github.com/lmajewski/y2038-tests/commits/master

Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de
  

On 14/01/2021 13:32, Lukasz Majewski wrote:
> This change adds new test to assess ppoll()'s timeout related
> functionality (the struct pollfd does not provide valid fd to wait
> for - just wait for timeout).
> 
> To be more specific - two use cases are checked:
> - if ppoll() times out immediately when passed struct timespec has zero
> values of tv_nsec and tv_sec.
> - if ppoll() times out after timeout specified in passed argument
> 
> ---
> Changes for v2:
> - Remove _GNU_SOURCE definition if not already defined
> - Replace clock_gettime with xclock_gettime
> - Use FAIL_EXIT1 instead of plain ret value returning from the test
> ---
>  sysdeps/unix/sysv/linux/Makefile    |  2 +-
>  sysdeps/unix/sysv/linux/tst-ppoll.c | 62 +++++++++++++++++++++++++++++
>  2 files changed, 63 insertions(+), 1 deletion(-)
>  create mode 100644 sysdeps/unix/sysv/linux/tst-ppoll.c
> 
> diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
> index 7503b356c8..f4029a74ca 100644
> --- a/sysdeps/unix/sysv/linux/Makefile
> +++ b/sysdeps/unix/sysv/linux/Makefile
> @@ -108,7 +108,7 @@ tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \
>  	 test-errno-linux tst-memfd_create tst-mlock2 tst-pkey \
>  	 tst-rlimit-infinity tst-ofdlocks tst-gettid tst-gettid-kill \
>  	 tst-tgkill tst-sysvsem-linux tst-sysvmsg-linux tst-sysvshm-linux \
> -	 tst-timerfd
> +	 tst-timerfd tst-ppoll
>  tests-internal += tst-ofdlocks-compat tst-sigcontext-get_pc
>  
>  CFLAGS-tst-sigcontext-get_pc.c = -fasynchronous-unwind-tables

Ok.

> diff --git a/sysdeps/unix/sysv/linux/tst-ppoll.c b/sysdeps/unix/sysv/linux/tst-ppoll.c
> new file mode 100644
> index 0000000000..eeff97f103
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/tst-ppoll.c
> @@ -0,0 +1,62 @@
> +/* Test for ppoll timeout
> +   Copyright (C) 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 <time.h>
> +#include <poll.h>
> +#include <support/check.h>
> +#include <support/xtime.h>
> +
> +/* Timeout in seconds for PPOLL.  */
> +#define PPOLL_TIMEOUT 2
> +/* Timeout for test program - must be larger than PPOLL_TIMEOUT.  */
> +#define TIMEOUT 3

This define is unused. 

> +
> +static int test_ppoll_timeout (int timeout)
> +{
> +  struct timespec tv0 = { 0, 0 }, tv1 = { 0, 0 }, tv = { 0, 0 };
> +  struct pollfd fds = { -1, 0, 0 };   /* Ignore fds - just wait for timeout.  */
> +  int ret;
> +
> +  tv.tv_sec = timeout;
> +
> +  xclock_gettime (CLOCK_REALTIME, &tv0);
> +
> +  ret = ppoll (&fds, 1, &tv, 0);
> +  if (ret != 0)
> +      FAIL_EXIT1 ("*** ppoll failed: %m\n");
> +
> +  xclock_gettime (CLOCK_REALTIME, &tv1);
> +  if (tv0.tv_sec + timeout != tv1.tv_sec)
> +      FAIL_EXIT1 ("*** ppoll failed to timeout after %d [s]\n", timeout);
> +
> +  return 0;
> +}
> +
> +static int
> +do_test (void)
> +{
> +  /* Check if ppoll exits immediately.  */
> +  test_ppoll_timeout (0);
> +
> +  /* Check if ppoll exits after specified timeout.  */
> +  test_ppoll_timeout (PPOLL_TIMEOUT);
> +
> +  return 0;
> +}
> +
> +#include <support/test-driver.c>

The exactly timeout check is subjected to a scheduler pressure and it might
indicate false positive depending of the system load.  It would be better to
check only if subsequent clock_gettime returns a time after previously than
the ppoll check.  Like:

static int test_ppoll_timeout (bool zero_tmo)
{ 
  /* We wait for half a second.  */
  struct timespec ts;
  xclock_gettime (CLOCK_REALTIME, &ts);
  struct timespec timeout = make_timespec (0, zero_tmo ? 0 : TIMESPEC_HZ/2);
  ts = timespec_add (ts, timeout);

  /* Ignore fds - just wait for timeout.  */
  struct pollfd fds = { -1, 0, 0 };
  TEST_COMPARE (ppoll (&fds, 1, &timeout, 0), 0);

  TEST_TIMESPEC_NOW_OR_AFTER (CLOCK_REALTIME, ts);

  return 0;
}

static int
do_test (void)
{ 
  /* Check if ppoll exits immediately.  */
  test_ppoll_timeout (true);

  /* Check if ppoll exits after specified timeout.  */
  test_ppoll_timeout (false);

  return 0;
}
  

Hi Adhemerval,

> On 14/01/2021 13:32, Lukasz Majewski wrote:
> > This change adds new test to assess ppoll()'s timeout related
> > functionality (the struct pollfd does not provide valid fd to wait
> > for - just wait for timeout).
> > 
> > To be more specific - two use cases are checked:
> > - if ppoll() times out immediately when passed struct timespec has
> > zero values of tv_nsec and tv_sec.
> > - if ppoll() times out after timeout specified in passed argument
> > 
> > ---
> > Changes for v2:
> > - Remove _GNU_SOURCE definition if not already defined
> > - Replace clock_gettime with xclock_gettime
> > - Use FAIL_EXIT1 instead of plain ret value returning from the test
> > ---
> >  sysdeps/unix/sysv/linux/Makefile    |  2 +-
> >  sysdeps/unix/sysv/linux/tst-ppoll.c | 62
> > +++++++++++++++++++++++++++++ 2 files changed, 63 insertions(+), 1
> > deletion(-) create mode 100644 sysdeps/unix/sysv/linux/tst-ppoll.c
> > 
> > diff --git a/sysdeps/unix/sysv/linux/Makefile
> > b/sysdeps/unix/sysv/linux/Makefile index 7503b356c8..f4029a74ca
> > 100644 --- a/sysdeps/unix/sysv/linux/Makefile
> > +++ b/sysdeps/unix/sysv/linux/Makefile
> > @@ -108,7 +108,7 @@ tests += tst-clone tst-clone2 tst-clone3
> > tst-fanotify tst-personality \ test-errno-linux tst-memfd_create
> > tst-mlock2 tst-pkey \ tst-rlimit-infinity tst-ofdlocks tst-gettid
> > tst-gettid-kill \ tst-tgkill tst-sysvsem-linux tst-sysvmsg-linux
> > tst-sysvshm-linux \
> > -	 tst-timerfd
> > +	 tst-timerfd tst-ppoll
> >  tests-internal += tst-ofdlocks-compat tst-sigcontext-get_pc
> >  
> >  CFLAGS-tst-sigcontext-get_pc.c = -fasynchronous-unwind-tables  
> 
> Ok.
> 
> > diff --git a/sysdeps/unix/sysv/linux/tst-ppoll.c
> > b/sysdeps/unix/sysv/linux/tst-ppoll.c new file mode 100644
> > index 0000000000..eeff97f103
> > --- /dev/null
> > +++ b/sysdeps/unix/sysv/linux/tst-ppoll.c
> > @@ -0,0 +1,62 @@
> > +/* Test for ppoll timeout
> > +   Copyright (C) 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 <time.h>
> > +#include <poll.h>
> > +#include <support/check.h>
> > +#include <support/xtime.h>
> > +
> > +/* Timeout in seconds for PPOLL.  */
> > +#define PPOLL_TIMEOUT 2
> > +/* Timeout for test program - must be larger than PPOLL_TIMEOUT.
> > */ +#define TIMEOUT 3  
> 
> This define is unused. 

When TIMEOUT is not specified - the default time out for test is used
(2 seconds). For the ppoll test we want to wait for 2 seconds, so
without this local #define TIMEOUT 3 the test is terminated by glibc
test suite before we go out from the ppoll.

However, as we now wait for 0.5 sec, it is feasible to just remove it
and used default settings.

> 
> > +
> > +static int test_ppoll_timeout (int timeout)
> > +{
> > +  struct timespec tv0 = { 0, 0 }, tv1 = { 0, 0 }, tv = { 0, 0 };
> > +  struct pollfd fds = { -1, 0, 0 };   /* Ignore fds - just wait
> > for timeout.  */
> > +  int ret;
> > +
> > +  tv.tv_sec = timeout;
> > +
> > +  xclock_gettime (CLOCK_REALTIME, &tv0);
> > +
> > +  ret = ppoll (&fds, 1, &tv, 0);
> > +  if (ret != 0)
> > +      FAIL_EXIT1 ("*** ppoll failed: %m\n");
> > +
> > +  xclock_gettime (CLOCK_REALTIME, &tv1);
> > +  if (tv0.tv_sec + timeout != tv1.tv_sec)
> > +      FAIL_EXIT1 ("*** ppoll failed to timeout after %d [s]\n",
> > timeout); +
> > +  return 0;
> > +}
> > +
> > +static int
> > +do_test (void)
> > +{
> > +  /* Check if ppoll exits immediately.  */
> > +  test_ppoll_timeout (0);
> > +
> > +  /* Check if ppoll exits after specified timeout.  */
> > +  test_ppoll_timeout (PPOLL_TIMEOUT);
> > +
> > +  return 0;
> > +}
> > +
> > +#include <support/test-driver.c>  
> 
> The exactly timeout check is subjected to a scheduler pressure and it
> might indicate false positive depending of the system load.  It would
> be better to check only if subsequent clock_gettime returns a time
> after previously than the ppoll check.  Like:
> 
> static int test_ppoll_timeout (bool zero_tmo)
> { 
>   /* We wait for half a second.  */
>   struct timespec ts;
>   xclock_gettime (CLOCK_REALTIME, &ts);
>   struct timespec timeout = make_timespec (0, zero_tmo ? 0 :
> TIMESPEC_HZ/2); ts = timespec_add (ts, timeout);
> 
>   /* Ignore fds - just wait for timeout.  */
>   struct pollfd fds = { -1, 0, 0 };
>   TEST_COMPARE (ppoll (&fds, 1, &timeout, 0), 0);
> 
>   TEST_TIMESPEC_NOW_OR_AFTER (CLOCK_REALTIME, ts);
> 
>   return 0;
> }
> 
> static int
> do_test (void)
> { 
>   /* Check if ppoll exits immediately.  */
>   test_ppoll_timeout (true);
> 
>   /* Check if ppoll exits after specified timeout.  */
>   test_ppoll_timeout (false);
> 
>   return 0;
> }
> 
> 

Thanks for the tip. I will add this code to the test.


Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de