LIBRARY_PATH and foreign binaries: error while loading shared libraries

LIBRARY_PATH and foreign binaries: error while loading shared libraries

[Pierre Neidhardt]

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I want to run some binaries which were not compiled on GuixSD
(e.g. games from Humble Bundle).

Two issues:

> /path/to/foreign/binary
/path/to/foreign/binary: No such file or directory

This is because the path to the linker is wrong:

> file /path/to/foreign/binary
/path/to/foreign/binary: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.24, BuildID[sha1]=edf4cff78e6710ff4f7ac14cb99b38aefed2659e, stripped

I can fix it with

> patchelf --set-interpreter "$(realpath "$(which sh)")" /path/to/foreign/binary

(Is this the commended way?)

Now it starts up but the linker fails to find some libraries:

> /path/to/foreign/binary
/path/to/foreign/binary: error while loading shared libraries: libstdc++.so.6: cannot open shared object file: No such file or directory

> ldd /path/to/foreign/binary
	linux-vdso.so.1 (0x00007ffd71355000)
	libdl.so.2 => /gnu/store/4sqaib7c2dfjv62ivrg9b8wa7bh226la-glibc-2.26.105-g0890d5379c/lib/libdl.so.2 (0x00007fa746ffd000)
	libpthread.so.0 => /gnu/store/4sqaib7c2dfjv62ivrg9b8wa7bh226la-glibc-2.26.105-g0890d5379c/lib/libpthread.so.0 (0x00007fa746ddf000)
	librt.so.1 => /gnu/store/4sqaib7c2dfjv62ivrg9b8wa7bh226la-glibc-2.26.105-g0890d5379c/lib/librt.so.1 (0x00007fa746bd7000)
	libstdc++.so.6 => not found
	libm.so.6 => /gnu/store/4sqaib7c2dfjv62ivrg9b8wa7bh226la-glibc-2.26.105-g0890d5379c/lib/libm.so.6 (0x00007fa74688b000)
	libgcc_s.so.1 => not found
	libc.so.6 => /gnu/store/4sqaib7c2dfjv62ivrg9b8wa7bh226la-glibc-2.26.105-g0890d5379c/lib/libc.so.6 (0x00007fa7464d9000)
	/gnu/store/4sqaib7c2dfjv62ivrg9b8wa7bh226la-glibc-2.26.105-g0890d5379c/lib/ld-linux-x86-64.so.2 (0x00007fa747201000)

The "missing" libraries are indeed in my ~/.guix-profile/lib.  This
folder is properly referenced in the environment:

> env | grep LIBRARY_PATH
LIBRARY_PATH=/home/ambrevar/.guix-profile/lib

My understanding is that the LIBRARY_PATH is only used for compiling,
not at runtime.  But then how come some libraries are found and not others?
Or is it just true for the libs in the glibc package, because
ld-linux-x86-64.so.2 is part of it, so it searchs its own path?

If I export LD_LIBRARY_PATH to the value of LIBRARY_PATH, then it works:

> export LD_LIBRARY_PATH=$LIBRARY_PATH
> /path/to/foreign/binary

Is there a better way?

-- 
Pierre Neidhardt

Price does not include taxes.

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Re: LIBRARY_PATH and foreign binaries: error while loading shared libraries

[Pierre Neidhardt]

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Pierre Neidhardt <ambrevar@gmail.com> writes:

> I can fix it with
>
>> patchelf --set-interpreter "$(realpath "$(which sh)")" /path/to/foreign/binary

Copy/paste mistake, the correct command is

> patchelf --set-interpreter "$(patchelf --print-interpreter "$(realpath "$(which sh)")")" /path/to/foreign/binary

-- 
Pierre Neidhardt


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Re: LIBRARY_PATH and foreign binaries: error while loading shared libraries

[Ricardo Wurmus]

Hi Pierre,

>> /path/to/foreign/binary
> /path/to/foreign/binary: No such file or directory
>
> This is because the path to the linker is wrong:
>
>> file /path/to/foreign/binary
> /path/to/foreign/binary: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.24, BuildID[sha1]=edf4cff78e6710ff4f7ac14cb99b38aefed2659e, stripped
>
> I can fix it with
>
>> patchelf --set-interpreter "$(realpath "$(which sh)")" /path/to/foreign/binary
>
> (Is this the commended way?)

It is one way that ensures that the correct linker is used.  Another way
is to install the glibc’s dynamic linker in the expected location at
/lib64/ld-linux-x86-64.so.2.

> The "missing" libraries are indeed in my ~/.guix-profile/lib.  This
> folder is properly referenced in the environment:
>
>> env | grep LIBRARY_PATH
> LIBRARY_PATH=/home/ambrevar/.guix-profile/lib

> My understanding is that the LIBRARY_PATH is only used for compiling,

Correct.  It is respected by the linker.

> not at runtime.  But then how come some libraries are found and not
> others?

That’s probably because the libraries it found end up there because of
patching the interpreter.

> If I export LD_LIBRARY_PATH to the value of LIBRARY_PATH, then it works:
>
>> export LD_LIBRARY_PATH=$LIBRARY_PATH
>> /path/to/foreign/binary
>
> Is there a better way?

The best way is to build the software from source.  Short of that you
can load individual libraries with LD_PRELOAD.  The most coarse-grain
solution is to use LD_LIBRARY_PATH.

--
Ricardo

Re: LIBRARY_PATH and foreign binaries: error while loading shared libraries

[Pierre Neidhardt]

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Thank you Ricardo for those clarifications.

-- 
Pierre Neidhardt

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Re: LIBRARY_PATH and foreign binaries: error while loading shared libraries

[Pierre Neidhardt]

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Ricardo Wurmus <rekado@elephly.net> writes:

> The best way is to build the software from source.  Short of that you
> can load individual libraries with LD_PRELOAD.  The most coarse-grain
> solution is to use LD_LIBRARY_PATH.

Where is LD_PRELOAD documented?
I could find it mentioned in (8)ld.so.

-- 
Pierre Neidhardt

Perilous to all of us are the devices of an art deeper than we ourselves
possess.
		-- Gandalf the Grey [J.R.R. Tolkien, "Lord of the Rings"]

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