[bug] glibc doesn't seem to be needed under Alpine Linux (README.md)

[x-yuri]

Please describe the bug

The readme says:

Nokogiri ships pre-compiled, "native" gems for the following platforms:

• Linux:
  • x86-linux and x86_64-linux (req: glibc >= 2.17)

which sounds like glibc is needed in this case. From what I can see it's not.

Help us reproduce what you're seeing

$ docker run --rm -it ruby:2.7.7-alpine3.16 sh
/ # gem install nokogiri
Fetching nokogiri-1.14.2-x86_64-linux.gem
Successfully installed nokogiri-1.14.2-x86_64-linux
1 gem installed
/ # ruby -rnokogiri -e ''

Expected behavior

According to the README it should fail.

Environment

# Nokogiri (1.14.2)
    ---
    warnings: []
    nokogiri:
      version: 1.14.2
      cppflags:
      - "-I/usr/local/bundle/gems/nokogiri-1.14.2-x86_64-linux/ext/nokogiri"
      - "-I/usr/local/bundle/gems/nokogiri-1.14.2-x86_64-linux/ext/nokogiri/include"
      - "-I/usr/local/bundle/gems/nokogiri-1.14.2-x86_64-linux/ext/nokogiri/include/libxml2"
      ldflags: []
    ruby:
      version: 2.7.7
      platform: x86_64-linux-musl
      gem_platform: x86_64-linux-musl
      description: ruby 2.7.7p221 (2022-11-24 revision 168ec2b1e5) [x86_64-linux-musl]
      engine: ruby
    libxml:
      source: packaged
      precompiled: true
      patches:
      - 0001-Remove-script-macro-support.patch
      - 0002-Update-entities-to-remove-handling-of-ssi.patch
      - 0003-libxml2.la-is-in-top_builddir.patch
      - '0009-allow-wildcard-namespaces.patch'
      libxml2_path: "/usr/local/bundle/gems/nokogiri-1.14.2-x86_64-linux/ext/nokogiri"
      memory_management: ruby
      iconv_enabled: true
      compiled: 2.10.3
      loaded: 2.10.3
    libxslt:
      source: packaged
      precompiled: true
      patches:
      - 0001-update-automake-files-for-arm64.patch
      datetime_enabled: true
      compiled: 1.1.37
      loaded: 1.1.37
    other_libraries:
      zlib: 1.2.13
      libgumbo: 1.0.0-nokogiri

Additional context

[flavorjones]

Thanks for asking this question. It feels like something may have changed in recent versions of Alpine because this definitely was a problem in the past, see https://nokogiri.org/tutorials/installing_nokogiri.html#linux-musl-error-loading-shared-library for the specifics.

I'll leave this open to look a bit deeper when I get some time. If you have the ability or desire to look into whether something changed so we can update docs, I would definitely welcome the help.

[x-yuri]

Error loading shared library ld-linux-x86-64.so.2: No such file or directory

Well, I tried it with Alpine Linux 3.7, ruby-2.5.0 and nokogiri-1.11.0. That's supposedly as old as it gets:

$ docker run --rm -it ruby:2.5.0-alpine3.7 sh
/ # apk update
/ # apk add build-base
/ # gem install racc -v 1.6.2

/ # gem install nokogiri -v 1.11.0
Fetching: nokogiri-1.11.0-x86_64-linux.gem (100%)
Successfully installed nokogiri-1.11.0-x86_64-linux
1 gem installed

/ # ldd /usr/local/bundle/gems/nokogiri-1.11.0-x86_64-linux/lib/nokogiri/2.5/nokogiri.so 2>&1 | less
	ldd (0x7f750dc4e000)
	libm.so.6 => ldd (0x7f750dc4e000)
	libdl.so.2 => ldd (0x7f750dc4e000)
	libpthread.so.0 => ldd (0x7f750dc4e000)
	libc.so.6 => ldd (0x7f750dc4e000)

/ # readelf -d /usr/local/bundle/gems/nokogiri-1.11.0-x86_64-linux/lib/nokogiri/2.5/nokogiri.so 2>&1 | grep NEEDED
 0x0000000000000001 (NEEDED)             Shared library: [libm.so.6]
 0x0000000000000001 (NEEDED)             Shared library: [libdl.so.2]
 0x0000000000000001 (NEEDED)             Shared library: [libpthread.so.0]
 0x0000000000000001 (NEEDED)             Shared library: [libc.so.6]

/ # ls -al /lib
total 2896
drwxr-xr-x    1 root     root          4096 Apr 10 18:17 .
drwxr-xr-x    1 root     root          4096 Apr 10 18:28 ..
drwxr-xr-x    1 root     root          4096 Jan  9  2018 apk
drwxr-xr-x    2 root     root          4096 Jan  9  2018 firmware
-rwxr-xr-x    1 root     root        563688 Aug  7  2019 ld-musl-x86_64.so.1
lrwxrwxrwx    1 root     root            19 Apr 10 18:17 libc.musl-x86_64.so.1 -> ld-musl-x86_64.so.1
lrwxrwxrwx    1 root     root            19 Jan  9  2018 libcrypto.so.42 -> libcrypto.so.42.0.0
-rwxr-xr-x    1 root     root       1714280 Nov  9  2017 libcrypto.so.42.0.0
lrwxrwxrwx    1 root     root            18 Feb 17  2018 libprocps.so.6 -> libprocps.so.6.0.0
-rwxr-xr-x    1 root     root         63392 Oct 31  2017 libprocps.so.6.0.0
lrwxrwxrwx    1 root     root            16 Jan  9  2018 libssl.so.44 -> libssl.so.44.0.1
-rwxr-xr-x    1 root     root        309664 Nov  9  2017 libssl.so.44.0.1
lrwxrwxrwx    1 root     root            16 Feb 17  2018 libtls.so.16 -> libtls.so.16.0.1
-rwxr-xr-x    1 root     root         55064 Nov  9  2017 libtls.so.16.0.1
-rw-r--r--    1 root     root        125882 Oct 31  2017 libz.a
lrwxrwxrwx    1 root     root            14 Feb 17  2018 libz.so -> libz.so.1.2.11
lrwxrwxrwx    1 root     root            14 Jan  9  2018 libz.so.1 -> libz.so.1.2.11
-rwxr-xr-x    1 root     root         91952 Oct 31  2017 libz.so.1.2.11
drwxr-xr-x    2 root     root          4096 Jan  9  2018 mdev

/ # ruby -rnokogiri -e ''

Can you suggest what to look for?

[flavorjones]

Ah, thanks for trying to figure this out. I realized after a bit of my own poking that this is only an issue on arm64 musl systems (and not for x86_64 musl systems):

$ docker run --platform linux/arm/v7 -it ruby:2.7.7-alpine /bin/sh

/ # uname -a
Linux 0b11b4053c07 5.19.0-1018-lowlatency #19~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Wed Feb 8 16:06:16 UTC 20 armv7l Linux

/ # gem install nokogiri
Fetching nokogiri-1.14.3-arm-linux.gem
Successfully installed nokogiri-1.14.3-arm-linux
1 gem installed

/ # nokogiri -v
Traceback (most recent call last):
	8: from /usr/local/bundle/bin/nokogiri:23:in `<main>'
	7: from /usr/local/bundle/bin/nokogiri:23:in `load'
	6: from /usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/bin/nokogiri:8:in `<top (required)>'
	5: from /usr/local/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:83:in `require'
	4: from /usr/local/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:83:in `require'
	3: from /usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/lib/nokogiri.rb:8:in `<top (required)>'
	2: from /usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/lib/nokogiri.rb:8:in `require_relative'
	1: from /usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/lib/nokogiri/extension.rb:7:in `<top (required)>'
/usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/lib/nokogiri/extension.rb:7:in `require_relative': Error loading shared library ld-linux-armhf.so.3: No such file or directory (needed by /usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/lib/nokogiri/2.7/nokogiri.so) - /usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/lib/nokogiri/2.7/nokogiri.so (LoadError)
	10: from /usr/local/bundle/bin/nokogiri:23:in `<main>'
	 9: from /usr/local/bundle/bin/nokogiri:23:in `load'
	 8: from /usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/bin/nokogiri:8:in `<top (required)>'
	 7: from /usr/local/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:83:in `require'
	 6: from /usr/local/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:83:in `require'
	 5: from /usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/lib/nokogiri.rb:8:in `<top (required)>'
	 4: from /usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/lib/nokogiri.rb:8:in `require_relative'
	 3: from /usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/lib/nokogiri/extension.rb:4:in `<top (required)>'
	 2: from /usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/lib/nokogiri/extension.rb:31:in `rescue in <top (required)>'
	 1: from /usr/local/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:83:in `require'
/usr/local/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:83:in `require': cannot load such file -- nokogiri/nokogiri (LoadError)
	9: from /usr/local/bundle/bin/nokogiri:23:in `<main>'
	8: from /usr/local/bundle/bin/nokogiri:23:in `load'
	7: from /usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/bin/nokogiri:8:in `<top (required)>'
	6: from /usr/local/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:147:in `require'
	5: from /usr/local/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:158:in `rescue in require'
	4: from /usr/local/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:158:in `require'
	3: from /usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/lib/nokogiri.rb:8:in `<top (required)>'
	2: from /usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/lib/nokogiri.rb:8:in `require_relative'
	1: from /usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/lib/nokogiri/extension.rb:7:in `<top (required)>'
/usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/lib/nokogiri/extension.rb:7:in `require_relative': Error loading shared library ld-linux-armhf.so.3: No such file or directory (needed by /usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/lib/nokogiri/2.7/nokogiri.so) - /usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/lib/nokogiri/2.7/nokogiri.so (LoadError)
	11: from /usr/local/bundle/bin/nokogiri:23:in `<main>'
	10: from /usr/local/bundle/bin/nokogiri:23:in `load'
	 9: from /usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/bin/nokogiri:8:in `<top (required)>'
	 8: from /usr/local/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:147:in `require'
	 7: from /usr/local/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:158:in `rescue in require'
	 6: from /usr/local/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:158:in `require'
	 5: from /usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/lib/nokogiri.rb:8:in `<top (required)>'
	 4: from /usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/lib/nokogiri.rb:8:in `require_relative'
	 3: from /usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/lib/nokogiri/extension.rb:4:in `<top (required)>'
	 2: from /usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/lib/nokogiri/extension.rb:31:in `rescue in <top (required)>'
	 1: from /usr/local/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:83:in `require'
/usr/local/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:83:in `require': cannot load such file -- nokogiri/nokogiri (LoadError)

/ # apk add gcompat
fetch https://dl-cdn.alpinelinux.org/alpine/v3.16/main/armv7/APKINDEX.tar.gz
fetch https://dl-cdn.alpinelinux.org/alpine/v3.16/community/armv7/APKINDEX.tar.gz
(1/2) Installing musl-obstack (1.2.3-r0)
(2/2) Installing gcompat (1.0.0-r4)
OK: 17 MiB in 40 packages

/ # nokogiri -v
# Nokogiri (1.14.3)
    ---
    warnings: []
    nokogiri:
      version: 1.14.3
      cppflags:
      - "-I/usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/ext/nokogiri"
      - "-I/usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/ext/nokogiri/include"
      - "-I/usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/ext/nokogiri/include/libxml2"
      ldflags: []
    ruby:
      version: 2.7.7
      platform: arm-linux-musleabihf
      gem_platform: arm-linux-musleabihf
      description: ruby 2.7.7p221 (2022-11-24 revision 168ec2b1e5) [arm-linux-musleabihf]
      engine: ruby
    libxml:
      source: packaged
      precompiled: true
      patches:
      - 0001-Remove-script-macro-support.patch
      - 0002-Update-entities-to-remove-handling-of-ssi.patch
      - 0003-libxml2.la-is-in-top_builddir.patch
      - '0009-allow-wildcard-namespaces.patch'
      libxml2_path: "/usr/local/bundle/gems/nokogiri-1.14.3-arm-linux/ext/nokogiri"
      memory_management: ruby
      iconv_enabled: true
      compiled: 2.10.4
      loaded: 2.10.4
    libxslt:
      source: packaged
      precompiled: true
      patches:
      - 0001-update-automake-files-for-arm64.patch
      datetime_enabled: true
      compiled: 1.1.37
      loaded: 1.1.37
    other_libraries:
      zlib: 1.2.13
      libgumbo: 1.0.0-nokogiri

I'm open to documentation changes if you'd like to clarify the README!

[x-yuri]

@flavorjones Can you possibly tell what --platform linux/arm/v7 does? Runs the image in a virtual machine with a (virtual) arm processor on MacOS? Because otherwise it will run it with an amd64/x86_64 processor? And that is probably unavailable under Linux (at least w/o a fair amount of effort)?

[flavorjones]

@x-yuri the --platform flag will download an OCI image with binaries for that architecture. In order to run that architecture on my x86_64-linux machine, I also install qemu (https://github.com/multiarch/qemu-user-static). There's a debian/ubuntu package available, apt install qemu-user-static. It's slow but it will run.