Bug 138420 – Undefined reference to `environ' when linking libgtest.so on FreeBSD

• Status: RESOLVED
• Resolution: FIXED
• Component: Tools / Tests

[Ting-Wei Lan]

I got this error when compiling WebKit trunk with debug on FreeBSD:

Linking CXX shared library ../../../lib/libgtest.so
CMakeFiles/gtest.dir/__/__/ThirdParty/gtest/src/gtest-death-test.cc.o: In function `testing::internal::GetEnviron()':
/usr/home/lantw44/webkit/source/WebKit/Source/ThirdParty/gtest/src/gtest-death-test.cc:846: undefined reference to `environ'

It seems it is caused by the -Wl,--no-undefined flag added in Source/cmake/OptionsCommon.cmake. The environ symbol is not defined in libc.so.7, but it exists in crt1.o.

[Ting-Wei Lan]

Created attachment 241660 [details]
Work around undefined reference error for gtest on FreeBSD

[Ting-Wei Lan]

Created attachment 245137 [details]
Work around undefined reference error for gtest on FreeBSD

[Ting-Wei Lan]

Created attachment 256294 [details]
Patch

[Martin Robinson]

Comment on attachment 256294 [details]
Patch

This bug should probably be fixed upstream and the fix should probably not leave symbols unresolved.

[Ting-Wei Lan]

(In reply to comment #4)
> Comment on attachment 256294 [details]
> Patch
> 
> This bug should probably be fixed upstream and

The upstream project doesn't have this problem because they don't use -Wl,--no-undefined.

> the fix should probably not leave symbols unresolved.

I leave it unresolved because I can't find other ways to solve the problem. The environ symbol doesn't exist in any shared library, so it can't be resolved by adding -l arguments. I also tried to add crt1.o to the linking arguments, but it also doesn't work.

If I use /usr/lib/crt1.o:
ld: /usr/lib/crt1.o: relocation R_X86_64_32 against `_DYNAMIC' can not be used when making a shared object; recompile with -fPIC
/usr/lib/crt1.o: error adding symbols: Bad value
clang++: error: linker command failed with exit code 1 (use -v to see invocation)

If I use /usr/lib/gcrt1.o:
ld: /usr/lib/gcrt1.o: relocation R_X86_64_32 against `_DYNAMIC' can not be used when making a shared object; recompile with -fPIC
/usr/lib/gcrt1.o: error adding symbols: Bad value
clang++: error: linker command failed with exit code 1 (use -v to see invocation)

If I use /usr/lib/Scrt1.o:
/usr/lib/Scrt1.o: In function `_start':
/usr/src/lib/csu/amd64/crt1.c:(.text+0xa4): undefined reference to `__preinit_array_start'
ld: /usr/lib/Scrt1.o: relocation R_X86_64_PC32 against undefined hidden symbol `__preinit_array_start' can not be used when making a shared object
ld: final link failed: Bad value
clang++: error: linker command failed with exit code 1 (use -v to see invocation)

[Martin Robinson]

(In reply to comment #5)
> (In reply to comment #4)
> > Comment on attachment 256294 [details]
> > Patch
> > 
> > This bug should probably be fixed upstream and
> 
> The upstream project doesn't have this problem because they don't use
> -Wl,--no-undefined.


I think a proper fix upstream would be to not use environ based on some conditional compilation flag.

[Ting-Wei Lan]

I sent a message to gtest upstream: https://groups.google.com/forum/#!topic/googletestframework/wrrMj_fmXMc

I hope I will get a reply ...

[Michael Catanzaro]

I don't think I quite understand the problem, what crt1.o is and why gtest does not link to it. Asking upstream to not use environ does not seem reasonable, and dropping use of --no-undefined does not seem desirable either.

[Ting-Wei Lan]

crt1.o contains the entrypoint of a C program, _start function. _start function makes argc, argv, environ and possibly other initialization works, and calls main function. environ global variable is in crt1.o on FreeBSD.

crt1.c, the file containing _start function:
http://svn.freebsd.org/base/releng/10.1/lib/csu/amd64/crt1.c

ignore_init.c, the file included by crt1.c and containing environ variable:
http://svn.freebsd.org/base/releng/10.1/lib/csu/common/ignore_init.c


When using a C compiler driver to make an executable, crt1.o and other crt*.o files are automatically added to the linker arguments. This can be found by running 'cc -v'.

gtest doesn't link to it because it is a shared library. It is not an executable and it does not have a vaild entrypoint.

[Ting-Wei Lan]

Created attachment 256844 [details]
Patch

[Michael Catanzaro]

Comment on attachment 256844 [details]
Patch

This can't hurt anything, so go ahead, but please add a note to Source/ThirdParty/gtest/README.WebKit.

[Ting-Wei Lan]

Created attachment 268072 [details]
Remove usage of environ in gtest

[Ting-Wei Lan]

I don't have commit privilege, so I have to get the patch reviewed again to add a note in Source/ThirdParty/gtest/README.WebKit.

[Michael Catanzaro]

Comment on attachment 268072 [details]
Remove usage of environ in gtest

View in context: https://bugs.webkit.org/attachment.cgi?id=268072&action=review

> Source/ThirdParty/gtest/src/gtest-death-test.cc:861
>    DeathTestAbort(String::Format("execve(%s, ...) in %s failed: %s",

Oops, should probably update this string too.

[Ting-Wei Lan]

Created attachment 268085 [details]
Remove usage of environ in gtest

[Michael Catanzaro]

Comment on attachment 268085 [details]
Remove usage of environ in gtest

Thanks. In the future, please set cq? to request commit.

[WebKit Commit Bot]

Comment on attachment 268085 [details]
Remove usage of environ in gtest

Rejecting attachment 268085 [details] from commit-queue.

Failed to run "['/Volumes/Data/EWS/WebKit/Tools/Scripts/webkit-patch', '--status-host=webkit-queues.webkit.org', '--bot-id=webkit-cq-03', 'validate-changelog', '--check-oops', '--non-interactive', 268085, '--port=mac']" exit_code: 1 cwd: /Volumes/Data/EWS/WebKit

/Volumes/Data/EWS/WebKit/Source/ThirdParty/ChangeLog neither lists a valid reviewer nor contains the string "Unreviewed" or "Rubber stamp" (case insensitive).

Full output: http://webkit-queues.webkit.org/results/639848

[Ting-Wei Lan]

Created attachment 268104 [details]
Patch

[WebKit Commit Bot]

Comment on attachment 268104 [details]
Patch

Clearing flags on attachment: 268104

Committed r194501: <http://trac.webkit.org/changeset/194501>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.