Libpthread symbol lookup error

snapcraft
1

I am trying to run the following classic core22 snap (Qt Debian packages + Qt Creator from source) on Ubuntu 20.04:

name: qtcreator
title: Qt Creator
base: core22
adopt-info: qtcreator
summary: Qt Creator

grade: stable
confinement: classic

parts:

  # install mesa with 'no-patchelf' for DRI drivers
  # https://forum.snapcraft.io/t/opengl-broken-in-classic-core20-snap-on-22-04/29401/2
  mesa-patchelf:
    plugin: nil
    stage-packages:
    - libgl1-mesa-dri
    build-attributes:
    - enable-patchelf
    stage:
    - -usr/lib/${CRAFT_ARCH_TRIPLET}/dri

  mesa-no-patchelf:
    plugin: nil
    stage-packages:
    - libgl1-mesa-dri
    build-attributes:
    - no-patchelf
    stage:
    - usr/lib/${CRAFT_ARCH_TRIPLET}/dri

  qtcreator:
    source: http://code.qt.io/qt-creator/qt-creator.git
    source-tag: v10.0.0
    source-depth: 1
    parse-info: [usr/local/share/metainfo/org.qt-project.qtcreator.appdata.xml]
    plugin: cmake
    cmake-generator: Ninja
    build-attributes:
    - enable-patchelf
    build-packages:
    - qt6-base-dev
    - qt6-base-private-dev
    - qt6-wayland-dev
    - qt6-declarative-dev
    - libqt6core5compat6-dev
    - libegl-dev
    - libgl-dev
    - libdw-dev
    stage-packages:
    - libqt6concurrent6
    - libqt6core6
    - libqt6printsupport6
    - libqt6sql6
    - libqt6test6
    - libqt6widgets6
    - libqt6xml6
    - libqt6core5compat6
    - qt6-qpa-plugins
    - qt6-wayland
    - libdw1

apps:
  qtcreator:
    command: usr/local/bin/qtcreator
    common-id: org.qt-project.qtcreator.desktop
    desktop: usr/local/share/applications/org.qt-project.qtcreator.desktop
    environment:
      LD_LIBRARY_PATH: ${SNAP}/usr/local/lib:${SNAP}/usr/lib/${CRAFT_ARCH_TRIPLET}
      LIBGL_DRIVERS_PATH: ${SNAP}/usr/lib/${CRAFT_ARCH_TRIPLET}/dri
      QT_QPA_PLATFORM: wayland;xcb

This will cause a symbol lookup error in libpthread.so:

/snap/qtcreator/x1/usr/local/bin/qtcreator: symbol lookup error: /lib/x86_64-linux-gnu/libpthread.so.0: undefined symbol: __libc_pthread_init, version GLIBC_PRIVATE

Opening a shell inside the snap (snap run --shell qtcreator) and checking the dynamic libraries:

$ lddtree /snap/qtcreator/x1/usr/local/bin/qtcreator
qtcreator => /snap/qtcreator/x1/usr/local/bin/qtcreator (interpreter => /snap/core22/current/lib64/ld-linux-x86-64.so.2)
[...]
        libglib-2.0.so.0 => /snap/core22/current/lib/x86_64-linux-gnu/libglib-2.0.so.0
            libpcre.so.3 => /lib/x86_64-linux-gnu/libpcre.so.3
                libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0
[...]

shows that while the snap uses its own libglib-2.0, this one is referencing libraries (libpcre.so, libpthread.so) outside the snap.

It seems that patchelf is not properly setting the rpath for all libraries.

2

This sounds like it is due to libpcre being looked up relative to libglib-2.0’s RPATH, which is not set.

I’m not sure there is a great solution to this. But if you could ensure qtcreator was built such that it directly links to libpcre and libpthread (i.e. so they’re not being pulled in transitively), it’s RPATH should take precedence.

3

How can I do this? Is this possible without patching the source code? How do I force snapcraft to run patchelf on all dependant libraries?