[v3,1/3] Add and use link-test-modules-rpath-link [BZ #28455]

  DT_RUNPATH is only used to find the immediate dependencies of the
executable or shared object containing the DT_RUNPATH entry:

1. Define link-test-modules-rpath-link if $(build-hardcoded-path-in-tests)
is yes.
2. Use $(link-test-modules-rpath-link) in build-module-helper so that
test modules can dlopen modules with DT_RUNPATH.
3. Add a test to show why link-test-modules-rpath-link is needed.

This partially fixes BZ #28455.
---
 Makeconfig           |  2 ++
 Makerules            |  1 +
 elf/Makefile         |  7 +++++++
 elf/tst-global2.c    | 32 ++++++++++++++++++++++++++++++++
 elf/tst-globalmod2.c | 41 +++++++++++++++++++++++++++++++++++++++++
 5 files changed, 83 insertions(+)
 create mode 100644 elf/tst-global2.c
 create mode 100644 elf/tst-globalmod2.c
  

On 12/8/21 10:24, H.J. Lu wrote:
> DT_RUNPATH is only used to find the immediate dependencies of the
> executable or shared object containing the DT_RUNPATH entry:
> 
> 1. Define link-test-modules-rpath-link if $(build-hardcoded-path-in-tests)
> is yes.
> 2. Use $(link-test-modules-rpath-link) in build-module-helper so that
> test modules can dlopen modules with DT_RUNPATH.
> 3. Add a test to show why link-test-modules-rpath-link is needed.

I think should go in regardless of my suggestions in 3/3.

Please post a v4 that is distinct from your series and I'll ACK that.

> This partially fixes BZ #28455.
> ---
>  Makeconfig           |  2 ++
>  Makerules            |  1 +
>  elf/Makefile         |  7 +++++++
>  elf/tst-global2.c    | 32 ++++++++++++++++++++++++++++++++
>  elf/tst-globalmod2.c | 41 +++++++++++++++++++++++++++++++++++++++++
>  5 files changed, 83 insertions(+)
>  create mode 100644 elf/tst-global2.c
>  create mode 100644 elf/tst-globalmod2.c
> 
> diff --git a/Makeconfig b/Makeconfig
> index 3fa2f13003..2e2b6dbdf9 100644
> --- a/Makeconfig
> +++ b/Makeconfig
> @@ -569,8 +569,10 @@ link-libc-rpath-link = -Wl,-rpath-link=$(rpath-link)
>  # build-hardcoded-path-in-tests.
>  ifeq (yes,$(build-hardcoded-path-in-tests))
>  link-libc-tests-rpath-link = $(link-libc-rpath)
> +link-test-modules-rpath-link = $(link-libc-rpath)

OK. Use $(link-libc-rpath) if we are using $(build-hardcoded-path-in-tests)
because with DT_RUNPATH we may need to find the paths with DT_RUNPATH.

>  else
>  link-libc-tests-rpath-link = $(link-libc-rpath-link)
> +link-test-modules-rpath-link =

OK. Otherwise nothing.

>  endif  # build-hardcoded-path-in-tests
>  
>  link-libc-between-gnulib = $(common-objpfx)libc.so$(libc.so-version) \
> diff --git a/Makerules b/Makerules
> index 8db0ca1296..7afba30039 100644
> --- a/Makerules
> +++ b/Makerules
> @@ -591,6 +591,7 @@ $(LINK.o) -shared -static-libgcc $(sysdep-LDFLAGS) $(rtld-LDFLAGS) \
>  	  $(if $($(@F)-no-z-defs)$(no-z-defs),,-Wl,-z,defs) \
>  	  -B$(csu-objpfx) $(load-map-file) \
>  	  $(LDFLAGS.so) $(LDFLAGS-$(@F:%.so=%).so) \
> +	  $(link-test-modules-rpath-link) \

OK.

>  	  -L$(subst :, -L,$(rpath-link)) -Wl,-rpath-link=$(rpath-link)
>  endef
>  
> diff --git a/elf/Makefile b/elf/Makefile
> index ef36008673..4b5bdcb08e 100644
> --- a/elf/Makefile
> +++ b/elf/Makefile
> @@ -232,6 +232,7 @@ tests += restest1 preloadtest loadfail multiload origtest resolvfail \
>  	 tst-dl-is_dso tst-ro-dynamic \
>  	 tst-audit18 \
>  	 tst-rtld-run-static \
> +	 tst-global2 \

Please split and sort to reduce conflicts.

>  #	 reldep9
>  tests-internal += loadtest unload unload2 circleload1 \
>  	 neededtest neededtest2 neededtest3 neededtest4 \
> @@ -374,6 +375,7 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \
>  		tst-dlmopen-gethostbyname-mod tst-ro-dynamic-mod \
>  		tst-auditmod18 \
>  		tst-audit18mod \
> +		tst-globalmod2 \

Likewise.

>  
>  # Most modules build with _ISOMAC defined, but those filtered out
>  # depend on internal headers.
> @@ -1310,6 +1312,11 @@ tst-audit8-ENV = LD_AUDIT=$(objpfx)tst-auditmod1.so
>  
>  $(objpfx)tst-global1.out: $(objpfx)testobj6.so $(objpfx)testobj2.so
>  
> +$(objpfx)tst-global2: $(objpfx)tst-globalmod2.so

OK. Dep is present for build.

> +$(objpfx)tst-global2.out: $(objpfx)reldepmod1.so $(objpfx)reldepmod4.so

OK. Dep on reldepmod4.so is present for correct buildordering.

> +LDFLAGS-tst-global2 = -Wl,--enable-new-dtags
> +LDFLAGS-tst-globalmod2.so = -Wl,--enable-new-dtags

OK. Force DT_RUNPATH.

> +
>  $(objpfx)order2.out: $(objpfx)order2mod1.so $(objpfx)order2mod2.so
>  $(objpfx)order2-cmp.out: $(objpfx)order2.out
>  	(echo "12345" | cmp $< -) > $@; \
> diff --git a/elf/tst-global2.c b/elf/tst-global2.c
> new file mode 100644
> index 0000000000..e929f526f4
> --- /dev/null
> +++ b/elf/tst-global2.c
> @@ -0,0 +1,32 @@
> +/* Test BZ #28455.

OK.

> +   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/>.  */
> +
> +/* In glibc configured with --enable-hardcoded-path-in-tests, a test
> +   program built with -Wl,--enable-new-dtags, which adds DT_RUNPATH,
> +   instead of DT_RPATH, can call a function in a shared library, which
> +   dlopens another shared library.  */
> +
> +extern int test (void);
> +
> +static int
> +do_test (void)
> +{
> +  return test ();
> +}
> +
> +#include <support/test-driver.c>
> diff --git a/elf/tst-globalmod2.c b/elf/tst-globalmod2.c
> new file mode 100644
> index 0000000000..6fd70a72a8
> --- /dev/null
> +++ b/elf/tst-globalmod2.c
> @@ -0,0 +1,41 @@
> +/* Test BZ #28455.
> +   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/>.  */
> +
> +/* In glibc configured with --enable-hardcoded-path-in-tests, a test
> +   program built with -Wl,--enable-new-dtags, which adds DT_RUNPATH,
> +   instead of DT_RPATH, can call a function in a shared library, which
> +   dlopens another shared library.  */
> +
> +#include <dlfcn.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +
> +extern int test (void);
> +
> +int
> +test (void)
> +{
> +  (void) dlopen ("reldepmod4.so", RTLD_LAZY | RTLD_GLOBAL);

OK. Will test that we can find the DSOs from build directory.

> +  if (dlsym (RTLD_DEFAULT, "call_me") != NULL)
> +    {
> +      puts ("found \"call_me\"");
> +      return EXIT_SUCCESS;
> +    }
> +  puts ("didn't find \"call_me\"");
> +  return EXIT_FAILURE;
> +}
>