Re: [PATCH] Rename and split elf/tst-dlopen-aout collection of tests

[Carlos O'Donell <carlos at redhat dot com>]

On 10/16/19 2:06 PM, Florian Weimer wrote:
> * Zack Weinberg:
> 
>> On Wed, Oct 16, 2019 at 11:06 AM Florian Weimer <fweimer@redhat.com> wrote:
>>>
>>> From the beginning, elf/tst-dlopen-aout has exercised two different
>>> bugs: (a) failure to report errors for a dlopen of the executable
>>> itself in some cases (bug 24900) and (b) incorrect rollback of the
>>> TLS modid allocation in case of a dlopen failure (bug 16634).
>>>
>>> This patch retains elf/tst-dlopen-aout for (b) and introduces a new
>>> set of tests, elf/tst-dlopen-self, for (a).  The elf/tst-dlopen-aout
>>> tests use the elf/tst-dlopen-self binaries (or iconv), so they are
>>> no longer self-dlopen tests.
>>
>> I don't know the dynamic linker well enough to review this change in
>> detail.  I like the idea of splitting up these two tests.  I want to
>> suggest that the (b) test should be renamed to something more
>> descriptive at the same time as (a) is moved to its own binary.
>> tst-dlopen-aout sounds like it tests something to do with an ELF
>> executable trying to dlopen() an a.out-format shared library.  (I
>> don't know if that was ever a thing that worked, but I could easily
>> believe that some ancient attempt to make it work had backward
>> compatibility implications that we're still stuck with, at least on
>> the older ABIs.)
> 
> Oh right, very good point.  I faced the same confusion when I first
> dealt with the test, but forgot about it.  Updated patch below.
> 

OK for master (minor typo in comment).

The test split looks good to me. I evaluated that 24900 was the minimum
I would expect for a test case that needs to test that particularly code
path and it looks good to me. You don't need threads, or any TLS usage,
you just want self-dlopen.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>


> 
> 8<------------------------------------------------------------------8<
> From the beginning, elf/tst-dlopen-aout has exercised two different
> bugs: (a) failure to report errors for a dlopen of the executable
> itself in some cases (bug 24900) and (b) incorrect rollback of the
> TLS modid allocation in case of a dlopen failure (bug 16634).
> 
> This commit replaces the test with elf/tst-dlopen-self for (a) and
> elf/tst-dlopen-tlsmodid for (b).  The latter tests use the
> elf/tst-dlopen-self binaries (or iconv) with dlopen, so they are
> no longer self-dlopen tests.
> 
> Tested on x86_64-linux-gnu and i686-linux-gnu, with a toolchain that
> does not default to PIE.

OK.

> -----
>  elf/Makefile                                       | 32 +++++++++----
>  elf/tst-dlopen-self-container.c                    | 19 ++++++++
>  ...open-aout-container.c => tst-dlopen-self-pie.c} |  4 +-
>  elf/tst-dlopen-self.c                              | 55 ++++++++++++++++++++++
>  elf/tst-dlopen-tlsmodid-container.c                | 39 +++++++++++++++
>  ...dlopen-aout-pie.c => tst-dlopen-tlsmodid-pie.c} |  5 +-
>  elf/tst-dlopen-tlsmodid.c                          | 25 ++++++++++
>  elf/{tst-dlopen-aout.c => tst-dlopen-tlsmodid.h}   | 22 +++++----
>  8 files changed, 177 insertions(+), 24 deletions(-)

OK. 

So we split like this:

tst-dlopen-aout -> tst-dlopen-tlsmodid + tst-dlopen-self (explicitly marked no-pie)

tst-dlopen-aout-container -> tst-dlopen-tlsmodid-container + tst-dlopen-self-container

tst-dlopen-aout-pie -> tst-dlopen-tlsmodid-pie + tst-dlopen-self-pie

Looks good to me.

> diff --git a/elf/Makefile b/elf/Makefile
> index dea51ca182..5e4cdb494f 100644
> --- a/elf/Makefile
> +++ b/elf/Makefile
> @@ -192,14 +192,16 @@ tests += restest1 preloadtest loadfail multiload origtest resolvfail \
>  	 tst-latepthread tst-tls-manydynamic tst-nodelete-dlclose \
>  	 tst-debug1 tst-main1 tst-absolute-sym tst-absolute-zero tst-big-note \
>  	 tst-unwind-ctor tst-unwind-main tst-audit13 \
> -	 tst-sonamemove-link tst-sonamemove-dlopen tst-dlopen-aout
> +	 tst-sonamemove-link tst-sonamemove-dlopen tst-dlopen-tlsmodid \
> +	 tst-dlopen-self

OK. Replace old test with two new tests.

>  #	 reldep9
>  tests-internal += loadtest unload unload2 circleload1 \
>  	 neededtest neededtest2 neededtest3 neededtest4 \
>  	 tst-tls3 tst-tls6 tst-tls7 tst-tls8 tst-dlmopen2 \
>  	 tst-ptrguard1 tst-stackguard1 tst-libc_dlvsym \
>  	 tst-create_format1
> -tests-container += tst-pldd tst-dlopen-aout-container
> +tests-container += tst-pldd tst-dlopen-tlsmodid-container \
> +  tst-dlopen-self-container

OK. Two containers which exercise $ORIGIN.

>  test-srcs = tst-pathopt
>  selinux-enabled := $(shell cat /selinux/enforce 2> /dev/null)
>  ifneq ($(selinux-enabled),1)
> @@ -308,8 +310,9 @@ test-xfail-tst-protected1b = yes
>  endif
>  ifeq (yesyes,$(have-fpie)$(build-shared))
>  modules-names += tst-piemod1
> -tests += tst-pie1 tst-pie2 tst-dlopen-pie tst-dlopen-aout-pie
> -tests-pie += tst-pie1 tst-pie2 tst-dlopen-aout-pie
> +tests += tst-pie1 tst-pie2 tst-dlopen-pie tst-dlopen-tlsmodid-pie \
> +  tst-dlopen-self-pie

OK. Two PIE tests.

> +tests-pie += tst-pie1 tst-pie2 tst-dlopen-tlsmodid-pie tst-dlopen-self-pie
>  ifeq (yes,$(have-protected-data))
>  tests += vismain
>  tests-pie += vismain
> @@ -1268,12 +1271,21 @@ $(objpfx)tst-addr1: $(libdl)
>  
>  $(objpfx)tst-thrlock: $(libdl) $(shared-thread-library)
>  
> -tst-tst-dlopen-aout-no-pie = yes
> -$(objpfx)tst-dlopen-aout: $(libdl) $(shared-thread-library)
> -CFLAGS-tst-dlopen-aout-pie.c += $(pie-ccflag)
> -$(objpfx)tst-dlopen-aout-pie: $(libdl) $(shared-thread-library)
> -$(objpfx)tst-dlopen-aout-container: $(libdl) $(shared-thread-library)
> -LDFLAGS-tst-dlopen-aout-container += -Wl,-rpath,\$$ORIGIN
> +tst-tst-dlopen-tlsmodid-no-pie = yes
> +$(objpfx)tst-dlopen-tlsmodid: $(libdl) $(shared-thread-library)
> +$(objpfx)tst-dlopen-tlsmodid.out: $(objpfx)tst-dlopen-self
> +CFLAGS-tst-dlopen-tlsmodid-pie.c += $(pie-ccflag)
> +$(objpfx)tst-dlopen-tlsmodid-pie: $(libdl) $(shared-thread-library)
> +$(objpfx)tst-dlopen-tlsmodid-pie.out: $(objpfx)tst-dlopen-self-pie
> +$(objpfx)tst-dlopen-tlsmodid-container: $(libdl) $(shared-thread-library)
> +LDFLAGS-tst-dlopen-tlsmodid-container += -Wl,-rpath,\$$ORIGIN
> +
> +tst-tst-dlopen-self-no-pie = yes
> +$(objpfx)tst-dlopen-self: $(libdl)
> +CFLAGS-tst-dlopen-self-pie.c += $(pie-ccflag)
> +$(objpfx)tst-dlopen-self-pie: $(libdl)
> +$(objpfx)tst-dlopen-self-container: $(libdl)
> +LDFLAGS-tst-dlopen-self-container += -Wl,-rpath,\$$ORIGIN
>  
>  CFLAGS-ifuncmain1pic.c += $(pic-ccflag)
>  CFLAGS-ifuncmain1picstatic.c += $(pic-ccflag)
> diff --git a/elf/tst-dlopen-self-container.c b/elf/tst-dlopen-self-container.c
> new file mode 100644
> index 0000000000..b1db238dec
> --- /dev/null
> +++ b/elf/tst-dlopen-self-container.c
> @@ -0,0 +1,19 @@
> +/* Check dlopen'ing the executable itself fails (bug 24900); container version.
> +   Copyright (C) 2014-2019 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; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#include "tst-dlopen-self.c"

OK.

> diff --git a/elf/tst-dlopen-aout-container.c b/elf/tst-dlopen-self-pie.c
> similarity index 87%
> rename from elf/tst-dlopen-aout-container.c
> rename to elf/tst-dlopen-self-pie.c
> index 702dbe04c4..855bccc5b5 100644
> --- a/elf/tst-dlopen-aout-container.c
> +++ b/elf/tst-dlopen-self-pie.c
> @@ -1,4 +1,4 @@
> -/* Test case for BZ #16634 and BZ#24900.  Container version.
> +/* Check that dlopen'ing the executable itself fails (bug 24900); PIE version.

OK.

>     Copyright (C) 2014-2019 Free Software Foundation, Inc.
>     This file is part of the GNU C Library.
>  
> @@ -16,4 +16,4 @@
>     License along with the GNU C Library; if not, see
>     <https://www.gnu.org/licenses/>.  */
>  
> -#include "tst-dlopen-aout.c"
> +#include "tst-dlopen-self.c"

OK.

> diff --git a/elf/tst-dlopen-self.c b/elf/tst-dlopen-self.c
> new file mode 100644
> index 0000000000..310f1b09d4
> --- /dev/null
> +++ b/elf/tst-dlopen-self.c
> @@ -0,0 +1,55 @@
> +/* Check that dlopen'ing the executable itself fails (bug 24900).
> +   Copyright (C) 2014-2019 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; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#include <dlfcn.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <support/check.h>
> +
> +/* Call dlopen and check that fails with an error message indicating
> +   an attempt to open an ET_EXEC or PIE object.  */
> +static void
> +check_dlopen_failure (const char *path)
> +{
> +  void *handle = dlopen (path, RTLD_LAZY);
> +  if (handle != NULL)
> +    FAIL_EXIT1 ("dlopen succeeded unexpectedly: %s", path);
> +
> +  const char *message = dlerror ();
> +  TEST_VERIFY_EXIT (message != NULL);
> +  if ((strstr (message,
> +	       "cannot dynamically load position-independent executable")
> +       == NULL)
> +      && strstr (message, "cannot dynamically load executable") == NULL)
> +    FAIL_EXIT1 ("invalid dlopen error message: \"%s\"", message);
> +}

OK. Matches original test.

> +
> +static int
> +do_test (int argc, char *argv[])
> +{
> +  check_dlopen_failure (argv[0]);
> +
> +  char *full_path = realpath (argv[0], NULL);
> +  check_dlopen_failure  (full_path);
> +  free (full_path);
> +
> +  return 0;
> +}

OK. No threads, just the dlopen failure. This is the minimal test case for bug 24900.

> +
> +#define TEST_FUNCTION_ARGV do_test
> +#include <support/test-driver.c>
> diff --git a/elf/tst-dlopen-tlsmodid-container.c b/elf/tst-dlopen-tlsmodid-container.c
> new file mode 100644
> index 0000000000..7654fcb214
> --- /dev/null
> +++ b/elf/tst-dlopen-tlsmodid-container.c
> @@ -0,0 +1,39 @@
> +/* Test case for BZ #16634.  Container version.
> +   Copyright (C) 2014-2019 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; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +/* This test use the iconv program as the test binary.  */

s/use/uses/g.

OK, using any binary inside the build is OK.

> +
> +#include <stdlib.h>
> +#include <support/support.h>
> +
> +static char *iconv_path;
> +
> +static __attribute__ ((constructor)) void
> +iconv_path_init (void)
> +{
> +  iconv_path = xasprintf ("%s/iconv", support_bindir_prefix);
> +}
> +
> +static __attribute__ ((destructor)) void
> +iconv_path_fini (void)
> +{
> +  free (iconv_path);
> +}


OK.

> +
> +#define TST_DLOPEN_TLSMODID_PATH iconv_path
> +#include "tst-dlopen-tlsmodid.h"

OK.

> diff --git a/elf/tst-dlopen-aout-pie.c b/elf/tst-dlopen-tlsmodid-pie.c
> similarity index 85%
> rename from elf/tst-dlopen-aout-pie.c
> rename to elf/tst-dlopen-tlsmodid-pie.c
> index 8d2009c0f3..db1176b12c 100644
> --- a/elf/tst-dlopen-aout-pie.c
> +++ b/elf/tst-dlopen-tlsmodid-pie.c
> @@ -1,4 +1,4 @@
> -/* Test case for BZ #16634 and BZ#24900.  PIE version.
> +/* Test case for BZ #16634.  PIE version.

OK.

>     Copyright (C) 2014-2019 Free Software Foundation, Inc.
>     This file is part of the GNU C Library.
>  
> @@ -16,4 +16,5 @@
>     License along with the GNU C Library; if not, see
>     <http://www.gnu.org/licenses/>.  */
>  
> -#include "tst-dlopen-aout.c"
> +#define TST_DLOPEN_TLSMODID_PATH "tst-dlopen-self-pie"
> +#include "tst-dlopen-tlsmodid.h"

OK.

> diff --git a/elf/tst-dlopen-tlsmodid.c b/elf/tst-dlopen-tlsmodid.c
> new file mode 100644
> index 0000000000..165edcb552
> --- /dev/null
> +++ b/elf/tst-dlopen-tlsmodid.c
> @@ -0,0 +1,25 @@
> +/* Test case for BZ #16634.  Non-PIE version.

OK.

> +
> +   Verify that incorrectly dlopen()ing an executable without
> +   __RTLD_OPENEXEC does not cause assertion in ld.so, and that it
> +   actually results in an error.
> +
> +   Copyright (C) 2014-2019 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; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#define TST_DLOPEN_TLSMODID_PATH "tst-dlopen-self"
> +#include "tst-dlopen-tlsmodid.h"

OK.

> diff --git a/elf/tst-dlopen-aout.c b/elf/tst-dlopen-tlsmodid.h
> similarity index 77%
> rename from elf/tst-dlopen-aout.c
> rename to elf/tst-dlopen-tlsmodid.h
> index b86d082bc1..c747cb1491 100644
> --- a/elf/tst-dlopen-aout.c
> +++ b/elf/tst-dlopen-tlsmodid.h
> @@ -1,4 +1,5 @@
> -/* Test case for BZ #16634 and BZ#24900.
> +/* Common code for tst-dlopen-tlsmodid, tst-dlopen-tlsmodid-pie,
> +   tst-dlopen-tlsmodid-container.

OK.

>  
>     Verify that incorrectly dlopen()ing an executable without
>     __RTLD_OPENEXEC does not cause assertion in ld.so, and that it
> @@ -21,6 +22,9 @@
>     License along with the GNU C Library; if not, see
>     <https://www.gnu.org/licenses/>.  */
>  
> +/* Before including this file, the macro TST_DLOPEN_TLSMODID_PATH must
> +   be defined, to specify the path used for the open operation.  */
> +

OK.

>  #include <dlfcn.h>
>  #include <pthread.h>
>  #include <stdio.h>
> @@ -38,14 +42,14 @@ fn (void *p)
>    return p;
>  }
>  
> -/* Call dlopen on PATH and check that fails with an error message
> -   indicating an attempt to open an ET_EXEC or PIE object.  */
> +/* Call dlopen and check that fails with an error message indicating
> +   an attempt to open an ET_EXEC or PIE object.  */
>  static void
> -check_dlopen_failure (const char *path)
> +check_dlopen_failure (void)
>  {
> -  void *handle = dlopen (path, RTLD_LAZY);
> +  void *handle = dlopen (TST_DLOPEN_TLSMODID_PATH, RTLD_LAZY);
>    if (handle != NULL)
> -    FAIL_EXIT1 ("dlopen succeeded unexpectedly: %s", path);
> +    FAIL_EXIT1 ("dlopen succeeded unexpectedly: %s", TST_DLOPEN_TLSMODID_PATH);
>  
>    const char *message = dlerror ();
>    TEST_VERIFY_EXIT (message != NULL);
> @@ -65,7 +69,7 @@ do_test (int argc, char *argv[])
>      {
>        pthread_t thr;
>  
> -      check_dlopen_failure (argv[0]);
> +      check_dlopen_failure ();

OK.

>  
>        /* We create threads to force TLS allocation, which triggers
>  	 the original bug i.e. running out of surplus slotinfo entries
> @@ -74,9 +78,7 @@ do_test (int argc, char *argv[])
>        xpthread_join (thr);
>      }
>  
> -  /* The elf subdirectory (or $ORIGIN in the container case) is on the
> -     library search path.  */
> -  check_dlopen_failure ("tst-dlopen-aout");
> +  check_dlopen_failure ();

OK. Same test as before but made common.

>  
>    return 0;
>  }
> 


-- 
Cheers,
Carlos.