bug#20102: Problem with ld.so RUNPATH on armhf

[Ludovic Courtès]

Mark H Weaver <address@hidden> skribis:

> 13440 
> execve("/gnu/store/p70wvylq6xdrlxblnk76k3ljgkrmvpnq-ld-wrapper-0/bin/ld", 
> ["/gnu/store/p70wvylq6xdrlxblnk76k3ljgkrmvpnq-ld-wrapper-0/bin/ld", 
> "--eh-frame-hdr", "-shared", "-dynamic-linker", 
> "/gnu/store/fbdjazgwy3zyx8qc5z4ag0j78k2d7raw-glibc-2.21/lib/ld-linux-armhf.so.3",
>  "-X", "-m", "armelf_linux_eabi", "-o", 
> "/tmp/nix-build-glibc-2.21.drv-0/build/elf/ld.so.new", 
> "-L/gnu/store/84bsc47g2052allrmh4ph6xaqvp6f4cm-perl-5.16.1/lib", 
> "-L/gnu/store/lakz7x2m4vqvvfdasn5x95a91rkqqs3c-bzip2-1.0.6/lib", 
> "-L/gnu/store/mrb163wwjc45hgrcjwmb6nxp8fgab3lk-xz-5.0.4/lib", 
> "-L/gnu/store/f1fnh2sp1j32jysdr2nw9z296iba6b5d-file-5.22/lib", 
> "-L/gnu/store/l9ji7gc640j2r8c1c561iwcnqpcd585m-gawk-4.1.1/lib", 
> "-L/gnu/store/w7gjnx5rz64mssxndnryazlwlhflfd2j-binutils-2.25/lib", 
> "-L/gnu/store/fbdjazgwy3zyx8qc5z4ag0j78k2d7raw-glibc-2.21/lib", 
> "-L/gnu/store/psmxs9gcr9l4arz7agmp94vm8fjwninv-glibc-utf8-locales-2.21/lib", 
> "-L/gnu/store/fc8kqk3dazn6mcgcjxd931752b2pf3wj-gcc-4.8.4-lib/lib/gcc/armv7l-unknown-linux-gnueabihf/4.8.4",
>  
> "-L/gnu/store/fc8kqk3dazn6mcgcjxd931752b2pf3wj-gcc-4.8.4-lib/lib/gcc/armv7l-unknown-linux-gnueabihf/4.8.4/../../..",
>  "-L/gnu/store/fbdjazgwy3zyx8qc5z4ag0j78k2d7raw-glibc-2.21/lib", "-z", 
> "combreloc", "-z", "relro", "--hash-style=both", "-z", "defs", 
> "/tmp/nix-build-glibc-2.21.drv-0/build/elf/librtld.os", 
> "--version-script=/tmp/nix-build-glibc-2.21.drv-0/build/ld.map", 
> "-soname=ld-linux-armhf.so.3", "-defsym=_begin=0"], [/* 55 vars */] 
> <unfinished ...>

Indeed, here’s what happens when passing it through ld-wrapper:

--8<---------------cut here---------------start------------->8---
$ GUIX_LD_WRAPPER_DEBUG=yes ld "--eh-frame-hdr" "-shared" "-dynamic-linker" 
"/gnu/store/fbdjazgwy3zyx8qc5z4ag0j78k2d7raw-glibc-2.21/lib/ld-linux-armhf.so.3"
 "-X" "-m" "armelf_linux_eabi" "-o" 
"/tmp/nix-build-glibc-2.21.drv-0/build/elf/ld.so.new" 
"-L/gnu/store/84bsc47g2052allrmh4ph6xaqvp6f4cm-perl-5.16.1/lib" 
"-L/gnu/store/lakz7x2m4vqvvfdasn5x95a91rkqqs3c-bzip2-1.0.6/lib" 
"-L/gnu/store/mrb163wwjc45hgrcjwmb6nxp8fgab3lk-xz-5.0.4/lib" 
"-L/gnu/store/f1fnh2sp1j32jysdr2nw9z296iba6b5d-file-5.22/lib" 
"-L/gnu/store/l9ji7gc640j2r8c1c561iwcnqpcd585m-gawk-4.1.1/lib" 
"-L/gnu/store/w7gjnx5rz64mssxndnryazlwlhflfd2j-binutils-2.25/lib" 
"-L/gnu/store/fbdjazgwy3zyx8qc5z4ag0j78k2d7raw-glibc-2.21/lib" 
"-L/gnu/store/psmxs9gcr9l4arz7agmp94vm8fjwninv-glibc-utf8-locales-2.21/lib" 
"-L/gnu/store/fc8kqk3dazn6mcgcjxd931752b2pf3wj-gcc-4.8.4-lib/lib/gcc/armv7l-unknown-linux-gnueabihf/4.8.4"
 
"-L/gnu/store/fc8kqk3dazn6mcgcjxd931752b2pf3wj-gcc-4.8.4-lib/lib/gcc/armv7l-unknown-linux-gnueabihf/4.8.4/../../.."
 "-L/gnu/store/fbdjazgwy3zyx8qc5z4ag0j78k2d7raw-glibc-2.21/lib" "-z" 
"combreloc" "-z" "relro" "--hash-style=both" "-z" "defs" 
"/tmp/nix-build-glibc-2.21.drv-0/build/elf/librtld.os" 
"--version-script=/tmp/nix-build-glibc-2.21.drv-0/build/ld.map" 
"-soname=ld-linux-armhf.so.3" "-defsym=_begin=0"
ld-wrapper: invoking 
`/gnu/store/z9d24s2wkri1z0ix5r7qqyp7zy3dklb4-binutils-2.25/bin/ld' with 
("--eh-frame-hdr" "-shared" "-dynamic-linker" 
"/gnu/store/fbdjazgwy3zyx8qc5z4ag0j78k2d7raw-glibc-2.21/lib/ld-linux-armhf.so.3"
 "-X" "-m" "armelf_linux_eabi" "-o" 
"/tmp/nix-build-glibc-2.21.drv-0/build/elf/ld.so.new" 
"-L/gnu/store/84bsc47g2052allrmh4ph6xaqvp6f4cm-perl-5.16.1/lib" 
"-L/gnu/store/lakz7x2m4vqvvfdasn5x95a91rkqqs3c-bzip2-1.0.6/lib" 
"-L/gnu/store/mrb163wwjc45hgrcjwmb6nxp8fgab3lk-xz-5.0.4/lib" 
"-L/gnu/store/f1fnh2sp1j32jysdr2nw9z296iba6b5d-file-5.22/lib" 
"-L/gnu/store/l9ji7gc640j2r8c1c561iwcnqpcd585m-gawk-4.1.1/lib" 
"-L/gnu/store/w7gjnx5rz64mssxndnryazlwlhflfd2j-binutils-2.25/lib" 
"-L/gnu/store/fbdjazgwy3zyx8qc5z4ag0j78k2d7raw-glibc-2.21/lib" 
"-L/gnu/store/psmxs9gcr9l4arz7agmp94vm8fjwninv-glibc-utf8-locales-2.21/lib" 
"-L/gnu/store/fc8kqk3dazn6mcgcjxd931752b2pf3wj-gcc-4.8.4-lib/lib/gcc/armv7l-unknown-linux-gnueabihf/4.8.4"
 
"-L/gnu/store/fc8kqk3dazn6mcgcjxd931752b2pf3wj-gcc-4.8.4-lib/lib/gcc/armv7l-unknown-linux-gnueabihf/4.8.4/../../.."
 "-L/gnu/store/fbdjazgwy3zyx8qc5z4ag0j78k2d7raw-glibc-2.21/lib" "-z" 
"combreloc" "-z" "relro" "--hash-style=both" "-z" "defs" 
"/tmp/nix-build-glibc-2.21.drv-0/build/elf/librtld.os" 
"--version-script=/tmp/nix-build-glibc-2.21.drv-0/build/ld.map" 
"-soname=ld-linux-armhf.so.3" "-defsym=_begin=0" "-rpath" 
"/gnu/store/fbdjazgwy3zyx8qc5z4ag0j78k2d7raw-glibc-2.21/lib")
ld: unrecognised emulation mode: armelf_linux_eabi
--8<---------------cut here---------------end--------------->8---

Conversely, when “replaying” the command that’s used on x86_64, -rpath
is not added:

--8<---------------cut here---------------start------------->8---
$ GUIX_LD_WRAPPER_DEBUG=yes ld "--eh-frame-hdr" "-m" "elf_x86_64" "-shared" 
"-o" "/tmp/nix-build-glibc-2.21.drv-0/build/elf/ld.so.new" 
"-L/gnu/store/xxjla3x9lv9djgszi9g2i7sp3zdh2fhz-perl-5.16.1/lib" 
"-L/gnu/store/zf0lrd865zxwkx30zmmv2s9pm3cbnyq9-bzip2-1.0.6/lib" 
"-L/gnu/store/yc75pismby9n46pimi7l9ifjwmj2ybix-xz-5.0.4/lib" 
"-L/gnu/store/ip9ydlmc7kwb1q472rh8539rkplx8xgl-file-5.22/lib" 
"-L/gnu/store/vmlwh55kmsjk7mmrw5qi8n71f02l4w0p-gawk-4.1.1/lib" 
"-L/gnu/store/z9d24s2wkri1z0ix5r7qqyp7zy3dklb4-binutils-2.25/lib" 
"-L/gnu/store/wiqbxcvzj3r35hd55yxzz919b1dv1hnv-glibc-2.21/lib" 
"-L/gnu/store/43mpxdd1qwmlsfgnl79jy1zkkx25nz6r-glibc-utf8-locales-2.21/lib" 
"-L/gnu/store/h132igxl2lkj3sbfcbknn2rd493j7d1l-gcc-4.8.4-lib/lib/gcc/x86_64-unknown-linux-gnu/4.8.4"
 
"-L/gnu/store/h132igxl2lkj3sbfcbknn2rd493j7d1l-gcc-4.8.4-lib/lib/gcc/x86_64-unknown-linux-gnu/4.8.4/../../.."
 "-L/gnu/store/wiqbxcvzj3r35hd55yxzz919b1dv1hnv-glibc-2.21/lib" "-z" 
"combreloc" "-z" "relro" "--hash-style=both" "-z" "defs" 
"/tmp/nix-build-glibc-2.21.drv-0/build/elf/librtld.os" 
"--version-script=/tmp/nix-build-glibc-2.21.drv-0/build/ld.map" 
"-soname=ld-linux-x86-64.so.2" "-defsym=_begin=0"
ld-wrapper: invoking 
`/gnu/store/z9d24s2wkri1z0ix5r7qqyp7zy3dklb4-binutils-2.25/bin/ld' with 
("--eh-frame-hdr" "-m" "elf_x86_64" "-shared" "-o" 
"/tmp/nix-build-glibc-2.21.drv-0/build/elf/ld.so.new" 
"-L/gnu/store/xxjla3x9lv9djgszi9g2i7sp3zdh2fhz-perl-5.16.1/lib" 
"-L/gnu/store/zf0lrd865zxwkx30zmmv2s9pm3cbnyq9-bzip2-1.0.6/lib" 
"-L/gnu/store/yc75pismby9n46pimi7l9ifjwmj2ybix-xz-5.0.4/lib" 
"-L/gnu/store/ip9ydlmc7kwb1q472rh8539rkplx8xgl-file-5.22/lib" 
"-L/gnu/store/vmlwh55kmsjk7mmrw5qi8n71f02l4w0p-gawk-4.1.1/lib" 
"-L/gnu/store/z9d24s2wkri1z0ix5r7qqyp7zy3dklb4-binutils-2.25/lib" 
"-L/gnu/store/wiqbxcvzj3r35hd55yxzz919b1dv1hnv-glibc-2.21/lib" 
"-L/gnu/store/43mpxdd1qwmlsfgnl79jy1zkkx25nz6r-glibc-utf8-locales-2.21/lib" 
"-L/gnu/store/h132igxl2lkj3sbfcbknn2rd493j7d1l-gcc-4.8.4-lib/lib/gcc/x86_64-unknown-linux-gnu/4.8.4"
 
"-L/gnu/store/h132igxl2lkj3sbfcbknn2rd493j7d1l-gcc-4.8.4-lib/lib/gcc/x86_64-unknown-linux-gnu/4.8.4/../../.."
 "-L/gnu/store/wiqbxcvzj3r35hd55yxzz919b1dv1hnv-glibc-2.21/lib" "-z" 
"combreloc" "-z" "relro" "--hash-style=both" "-z" "defs" 
"/tmp/nix-build-glibc-2.21.drv-0/build/elf/librtld.os" 
"--version-script=/tmp/nix-build-glibc-2.21.drv-0/build/ld.map" 
"-soname=ld-linux-x86-64.so.2" "-defsym=_begin=0")
--8<---------------cut here---------------end--------------->8---

With a bit of additional debug, I can print the value of ‘libs’ in the
‘ld-wrapper’ procedure:

--8<---------------cut here---------------start------------->8---
;;; (libs 
("/gnu/store/fbdjazgwy3zyx8qc5z4ag0j78k2d7raw-glibc-2.21/lib/ld-linux-armhf.so.3"))
--8<---------------cut here---------------end--------------->8---

This one comes from the -dynamic-linker flag, which is not passed on
x86_64.

I believe this extra -dynamic-linker flag comes from a bogus ‘link’ spec
on ARM, solved by this:

--- gcc-4.8.4/gcc/config/arm/linux-elf.h.orig   2015-04-08 20:31:20.376900478 
+0200
+++ gcc-4.8.4/gcc/config/arm/linux-elf.h        2015-04-08 20:31:36.437014437 
+0200
@@ -65,7 +65,7 @@
    %{symbolic:-Bsymbolic} \
    %{!static: \
      %{rdynamic:-export-dynamic} \
-     -dynamic-linker " GNU_USER_DYNAMIC_LINKER "} \
+     %{!shared:-dynamic-linker " GNU_USER_DYNAMIC_LINKER "}} \
    -X \
    %{mbig-endian:-EB} %{mlittle-endian:-EL}" \
    SUBTARGET_EXTRA_LINK_SPEC

That way it would match GNU_USER_TARGET_LINK_SPEC in i386/gnu-user.h,
where -dynamic-linker appears within %{!static ... %{!shared ...}}.

So, could you do:

  (define patched-gcc
    (package
      (inherit gcc-4.8)
      (sources (origin (inherit (package-source gcc-4.8))
                 (patches ...)))))

build it, and then use it in the failed glibc build tree to rebuild
ld.so?


There are ways we could have worked around it, for instance by adding:

  (setenv "GUIX_LD_WRAPPER_DISABLE_RPATH" "yes")

in the glibc recipe.

But I think it’s better to understand what’s going on.

Thanks,
Ludo’.