[3/3] Add mremap tests

Add tests for MREMAP_MAYMOVE, MREMAP_FIXED and MREMAP_DONTUNMAP.  On
Linux, enable MREMAP_FIXED test for Linux kernel 2.3.31 and above.
Enable MREMAP_DONTUNMAP test for Linux kernel 5.7 and above.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
---
 misc/Makefile                        |  1 +
 misc/tst-mremap.c                    | 73 ++++++++++++++++++++++++++++
 sysdeps/generic/tst-mremap.h         | 24 +++++++++
 sysdeps/unix/sysv/linux/tst-mremap.h | 67 +++++++++++++++++++++++++
 4 files changed, 165 insertions(+)
 create mode 100644 misc/tst-mremap.c
 create mode 100644 sysdeps/generic/tst-mremap.h
 create mode 100644 sysdeps/unix/sysv/linux/tst-mremap.h

On 12/07/24 19:31, H.J. Lu wrote:
> Add tests for MREMAP_MAYMOVE, MREMAP_FIXED and MREMAP_DONTUNMAP.  On
> Linux, enable MREMAP_FIXED test for Linux kernel 2.3.31 and above.
> Enable MREMAP_DONTUNMAP test for Linux kernel 5.7 and above.
> 
> Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
> ---
>  misc/Makefile                        |  1 +
>  misc/tst-mremap.c                    | 73 ++++++++++++++++++++++++++++
>  sysdeps/generic/tst-mremap.h         | 24 +++++++++
>  sysdeps/unix/sysv/linux/tst-mremap.h | 67 +++++++++++++++++++++++++
>  4 files changed, 165 insertions(+)
>  create mode 100644 misc/tst-mremap.c
>  create mode 100644 sysdeps/generic/tst-mremap.h
>  create mode 100644 sysdeps/unix/sysv/linux/tst-mremap.h
> 
> diff --git a/misc/Makefile b/misc/Makefile
> index 5d17c562fe..96474a6886 100644
> --- a/misc/Makefile
> +++ b/misc/Makefile
> @@ -257,6 +257,7 @@ tests := \
>    tst-mntent-blank-passno \
>    tst-mntent-escape \
>    tst-mntent2 \
> +  tst-mremap \
>    tst-preadvwritev \
>    tst-preadvwritev2 \
>    tst-preadvwritev64 \
> diff --git a/misc/tst-mremap.c b/misc/tst-mremap.c
> new file mode 100644
> index 0000000000..03e01852cb
> --- /dev/null
> +++ b/misc/tst-mremap.c
> @@ -0,0 +1,73 @@
> +/* Basic mremap tests.
> +   Copyright (C) 2024 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 <errno.h>
> +#include <sys/mman.h>
> +#include <support/xstdlib.h>
> +#include <support/xunistd.h>
> +#include <support/check.h>
> +#include <support/test-driver.h>
> +
> +static void
> +test_mremap_fixed (void)
> +{
> +  size_t old_size = getpagesize ();
> +  size_t new_size = old_size + old_size;
> +  char *old_addr = xmmap (NULL, old_size, PROT_READ | PROT_WRITE,
> +			  MAP_PRIVATE | MAP_ANONYMOUS, -1);
> +  old_addr[0] = 1;
> +  old_addr[old_size - 1] = 2;
> +
> +  char *fixed_addr = xmmap (NULL, new_size, PROT_READ | PROT_WRITE,
> +			    MAP_PRIVATE | MAP_ANONYMOUS, -1);
> +  fixed_addr[0] = 1;
> +  fixed_addr[new_size - 1] = 2;
> +
> +  /* Test MREMAP_FIXED.  */
> +  char *new_addr = mremap (old_addr, old_size, new_size,
> +			   MREMAP_FIXED | MREMAP_MAYMOVE,
> +			   fixed_addr);
> +  TEST_VERIFY_EXIT (new_addr == fixed_addr);
> +  new_addr[0] = 1;
> +  new_addr[new_size - 1] = 2;
> +  xmunmap (new_addr, new_size);
> +}
> +
> +#include <tst-mremap.h>
> +
> +static int
> +do_test (void)
> +{
> +  size_t old_size = getpagesize ();
> +  char *old_addr = xmmap (NULL, old_size, PROT_READ | PROT_WRITE,
> +			  MAP_PRIVATE | MAP_ANONYMOUS, -1);
> +  old_addr[0] = 1;
> +  old_addr[old_size - 1] = 2;
> +
> +  /* Test MREMAP_MAYMOVE.  */
> +  size_t new_size = old_size + old_size;
> +  char *new_addr = mremap (old_addr, old_size, new_size, MREMAP_MAYMOVE);
> +  TEST_VERIFY_EXIT (new_addr != MAP_FAILED);
> +  new_addr[0] = 1;
> +  new_addr[new_size - 1] = 2;
> +  xmunmap (new_addr, new_size);
> +
> +  return do_additonal_test ();
> +}
> +
> +#include <support/test-driver.c>
> diff --git a/sysdeps/generic/tst-mremap.h b/sysdeps/generic/tst-mremap.h
> new file mode 100644
> index 0000000000..dbc760ca28
> --- /dev/null
> +++ b/sysdeps/generic/tst-mremap.h
> @@ -0,0 +1,24 @@
> +/* Additional mremap check.  Generic version.
> +   Copyright (C) 2024 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/>.  */
> +
> +static int
> +do_additonal_test (void)
> +{
> +  test_mremap_fixed ();
> +  return 0;
> +}
> diff --git a/sysdeps/unix/sysv/linux/tst-mremap.h b/sysdeps/unix/sysv/linux/tst-mremap.h
> new file mode 100644
> index 0000000000..1c1777e23d
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/tst-mremap.h
> @@ -0,0 +1,67 @@
> +/* Additional mremap check.  Linux version.
> +   Copyright (C) 2024 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 <linux-support.h>
> +
> +static void
> +test_mremap_dontunmap (void)
> +{
> +  size_t old_size = getpagesize ();
> +  size_t new_size = old_size;
> +  char *old_addr = xmmap (NULL, old_size, PROT_READ | PROT_WRITE,
> +			  MAP_PRIVATE | MAP_ANONYMOUS, -1);
> +  old_addr[0] = 1;
> +  old_addr[old_size - 1] = 2;
> +
> +  /* Create an available 64-page mmap region.  */
> +  size_t fixed_size = old_size * 64;
> +  char *fixed_addr = xmmap (NULL, fixed_size, PROT_READ | PROT_WRITE,
> +			    MAP_PRIVATE | MAP_ANONYMOUS, -1);
> +  xmunmap (fixed_addr, fixed_size);
> +
> +  /* Test MREMAP_DONTUNMAP.  It should return FIXED_ADDR created above.  */
> +  char *new_addr = mremap (old_addr, old_size, new_size,
> +			   MREMAP_DONTUNMAP | MREMAP_MAYMOVE,
> +			   fixed_addr);
> +  TEST_VERIFY_EXIT (fixed_addr == new_addr);
> +  old_addr[0] = 3;
> +  old_addr[old_size - 1] = 4;
> +  new_addr[0] = 1;
> +  new_addr[new_size - 1] = 2;
> +  xmunmap (new_addr, new_size);
> +  xmunmap (old_addr, old_size);
> +}
> +
> +static int
> +do_additonal_test (void)
> +{
> +  unsigned int kernel = get_linux_kernel_version ();
> +  TEST_VERIFY_EXIT (kernel != 0);
> +
> +  /* MREMAP_FIXED was added to Linux kernel 2.3.31.  */
> +  if (kernel < make_linux_kernel_version (2, 3, 31))
> +    return EXIT_UNSUPPORTED;
> +  test_mremap_fixed ();
> +
> +  /* MREMAP_DONTUNMAP was added to Linux kernel 5.7.  */
> +  if (kernel < make_linux_kernel_version (5, 7, 0))
> +    return EXIT_UNSUPPORTED;

I do not think it is a good strategy to add Linux version checks on runtime
tests, it would always be trick to handle possible backports (where either 
the test will be flaky or have less coverage).

There is no need to handle MREMAP_FIXED, since we already have a minimum
required version that way higher (even though we do not enforce it anymore).

Also, mremap before 5.7 already handle invalid flags with EINVAL, so assuming
that we issue a valid mremap we can check that and valid return address or
EINVAL as valid.  We won't catch some invalid mishandled inputs, but I think 
for the C wrapper tests it should be suffice.

> +  test_mremap_dontunmap ();
> +
> +  return 0;
> +}

On Tue, Jul 16, 2024, 8:32 PM Adhemerval Zanella Netto <
adhemerval.zanella@linaro.org> wrote:

>
>
> On 12/07/24 19:31, H.J. Lu wrote:
> > Add tests for MREMAP_MAYMOVE, MREMAP_FIXED and MREMAP_DONTUNMAP.  On
> > Linux, enable MREMAP_FIXED test for Linux kernel 2.3.31 and above.
> > Enable MREMAP_DONTUNMAP test for Linux kernel 5.7 and above.
> >
> > Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
> > ---
> >  misc/Makefile                        |  1 +
> >  misc/tst-mremap.c                    | 73 ++++++++++++++++++++++++++++
> >  sysdeps/generic/tst-mremap.h         | 24 +++++++++
> >  sysdeps/unix/sysv/linux/tst-mremap.h | 67 +++++++++++++++++++++++++
> >  4 files changed, 165 insertions(+)
> >  create mode 100644 misc/tst-mremap.c
> >  create mode 100644 sysdeps/generic/tst-mremap.h
> >  create mode 100644 sysdeps/unix/sysv/linux/tst-mremap.h
> >
> > diff --git a/misc/Makefile b/misc/Makefile
> > index 5d17c562fe..96474a6886 100644
> > --- a/misc/Makefile
> > +++ b/misc/Makefile
> > @@ -257,6 +257,7 @@ tests := \
> >    tst-mntent-blank-passno \
> >    tst-mntent-escape \
> >    tst-mntent2 \
> > +  tst-mremap \
> >    tst-preadvwritev \
> >    tst-preadvwritev2 \
> >    tst-preadvwritev64 \
> > diff --git a/misc/tst-mremap.c b/misc/tst-mremap.c
> > new file mode 100644
> > index 0000000000..03e01852cb
> > --- /dev/null
> > +++ b/misc/tst-mremap.c
> > @@ -0,0 +1,73 @@
> > +/* Basic mremap tests.
> > +   Copyright (C) 2024 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 <errno.h>
> > +#include <sys/mman.h>
> > +#include <support/xstdlib.h>
> > +#include <support/xunistd.h>
> > +#include <support/check.h>
> > +#include <support/test-driver.h>
> > +
> > +static void
> > +test_mremap_fixed (void)
> > +{
> > +  size_t old_size = getpagesize ();
> > +  size_t new_size = old_size + old_size;
> > +  char *old_addr = xmmap (NULL, old_size, PROT_READ | PROT_WRITE,
> > +                       MAP_PRIVATE | MAP_ANONYMOUS, -1);
> > +  old_addr[0] = 1;
> > +  old_addr[old_size - 1] = 2;
> > +
> > +  char *fixed_addr = xmmap (NULL, new_size, PROT_READ | PROT_WRITE,
> > +                         MAP_PRIVATE | MAP_ANONYMOUS, -1);
> > +  fixed_addr[0] = 1;
> > +  fixed_addr[new_size - 1] = 2;
> > +
> > +  /* Test MREMAP_FIXED.  */
> > +  char *new_addr = mremap (old_addr, old_size, new_size,
> > +                        MREMAP_FIXED | MREMAP_MAYMOVE,
> > +                        fixed_addr);
> > +  TEST_VERIFY_EXIT (new_addr == fixed_addr);
> > +  new_addr[0] = 1;
> > +  new_addr[new_size - 1] = 2;
> > +  xmunmap (new_addr, new_size);
> > +}
> > +
> > +#include <tst-mremap.h>
> > +
> > +static int
> > +do_test (void)
> > +{
> > +  size_t old_size = getpagesize ();
> > +  char *old_addr = xmmap (NULL, old_size, PROT_READ | PROT_WRITE,
> > +                       MAP_PRIVATE | MAP_ANONYMOUS, -1);
> > +  old_addr[0] = 1;
> > +  old_addr[old_size - 1] = 2;
> > +
> > +  /* Test MREMAP_MAYMOVE.  */
> > +  size_t new_size = old_size + old_size;
> > +  char *new_addr = mremap (old_addr, old_size, new_size,
> MREMAP_MAYMOVE);
> > +  TEST_VERIFY_EXIT (new_addr != MAP_FAILED);
> > +  new_addr[0] = 1;
> > +  new_addr[new_size - 1] = 2;
> > +  xmunmap (new_addr, new_size);
> > +
> > +  return do_additonal_test ();
> > +}
> > +
> > +#include <support/test-driver.c>
> > diff --git a/sysdeps/generic/tst-mremap.h b/sysdeps/generic/tst-mremap.h
> > new file mode 100644
> > index 0000000000..dbc760ca28
> > --- /dev/null
> > +++ b/sysdeps/generic/tst-mremap.h
> > @@ -0,0 +1,24 @@
> > +/* Additional mremap check.  Generic version.
> > +   Copyright (C) 2024 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/>.  */
> > +
> > +static int
> > +do_additonal_test (void)
> > +{
> > +  test_mremap_fixed ();
> > +  return 0;
> > +}
> > diff --git a/sysdeps/unix/sysv/linux/tst-mremap.h
> b/sysdeps/unix/sysv/linux/tst-mremap.h
> > new file mode 100644
> > index 0000000000..1c1777e23d
> > --- /dev/null
> > +++ b/sysdeps/unix/sysv/linux/tst-mremap.h
> > @@ -0,0 +1,67 @@
> > +/* Additional mremap check.  Linux version.
> > +   Copyright (C) 2024 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 <linux-support.h>
> > +
> > +static void
> > +test_mremap_dontunmap (void)
> > +{
> > +  size_t old_size = getpagesize ();
> > +  size_t new_size = old_size;
> > +  char *old_addr = xmmap (NULL, old_size, PROT_READ | PROT_WRITE,
> > +                       MAP_PRIVATE | MAP_ANONYMOUS, -1);
> > +  old_addr[0] = 1;
> > +  old_addr[old_size - 1] = 2;
> > +
> > +  /* Create an available 64-page mmap region.  */
> > +  size_t fixed_size = old_size * 64;
> > +  char *fixed_addr = xmmap (NULL, fixed_size, PROT_READ | PROT_WRITE,
> > +                         MAP_PRIVATE | MAP_ANONYMOUS, -1);
> > +  xmunmap (fixed_addr, fixed_size);
> > +
> > +  /* Test MREMAP_DONTUNMAP.  It should return FIXED_ADDR created
> above.  */
> > +  char *new_addr = mremap (old_addr, old_size, new_size,
> > +                        MREMAP_DONTUNMAP | MREMAP_MAYMOVE,
> > +                        fixed_addr);
> > +  TEST_VERIFY_EXIT (fixed_addr == new_addr);
> > +  old_addr[0] = 3;
> > +  old_addr[old_size - 1] = 4;
> > +  new_addr[0] = 1;
> > +  new_addr[new_size - 1] = 2;
> > +  xmunmap (new_addr, new_size);
> > +  xmunmap (old_addr, old_size);
> > +}
> > +
> > +static int
> > +do_additonal_test (void)
> > +{
> > +  unsigned int kernel = get_linux_kernel_version ();
> > +  TEST_VERIFY_EXIT (kernel != 0);
> > +
> > +  /* MREMAP_FIXED was added to Linux kernel 2.3.31.  */
> > +  if (kernel < make_linux_kernel_version (2, 3, 31))
> > +    return EXIT_UNSUPPORTED;
> > +  test_mremap_fixed ();
> > +
> > +  /* MREMAP_DONTUNMAP was added to Linux kernel 5.7.  */
> > +  if (kernel < make_linux_kernel_version (5, 7, 0))
> > +    return EXIT_UNSUPPORTED;
>
> I do not think it is a good strategy to add Linux version checks on runtime
> tests, it would always be trick to handle possible backports (where either
> the test will be flaky or have less coverage).
>

Will check EINVAL in v2.


> There is no need to handle MREMAP_FIXED, since we already have a minimum
>

A test won't hurt.

required version that way higher (even though we do not enforce it anymore).
>
> Also, mremap before 5.7 already handle invalid flags with EINVAL, so
> assuming
> that we issue a valid mremap we can check that and valid return address or
> EINVAL as valid.  We won't catch some invalid mishandled inputs, but I
> think
> for the C wrapper tests it should be suffice.
>

Will change it in v2.


> > +  test_mremap_dontunmap ();
> > +
> > +  return 0;
> > +}
>