Add cross build task for Linux native gems.

The current GLIBC requirement of the nokogiri.so is version 2.17.
This means that distros before 2013 will be incompatible.

No need for libiconv on linux - it's part of glibc.

.cross_rubies

@@ -1,8 +1,16 @@
 2.5.0:i686-w64-mingw32
 2.5.0:x86_64-w64-mingw32
+2.5.0:i686-linux-gnu
+2.5.0:x86_64-linux-gnu
 2.4.0:i686-w64-mingw32
 2.4.0:x86_64-w64-mingw32
+2.4.0:i686-linux-gnu
+2.4.0:x86_64-linux-gnu
 2.3.0:i686-w64-mingw32
 2.3.0:x86_64-w64-mingw32
+2.3.0:i686-linux-gnu
+2.3.0:x86_64-linux-gnu
 2.2.2:i686-w64-mingw32
 2.2.2:x86_64-w64-mingw32
+2.2.2:i686-linux-gnu
+2.2.2:x86_64-linux-gnu

Rakefile

@@ -39,22 +39,34 @@ CrossRuby = Struct.new(:version, :host) {
   def platform
     @platform ||=
       case host
-      when /\Ax86_64-/
+      when /\Ax86_64.*mingw32/
         'x64-mingw32'
-      when /\Ai[3-6]86-/
+      when /\Ai[3-6]86.*mingw32/
         'x86-mingw32'
+      when /\Ax86_64.*linux/
+        'x86_64-linux'
+      when /\Ai[3-6]86.*linux/
+        'x86-linux'
       else
         raise "unsupported host: #{host}"
       end
   end
 
+  def windows?
+    !!(platform =~ /mingw|mswin/)
+  end
+
   def tool(name)
     (@binutils_prefix ||=
       case platform
       when 'x64-mingw32'
         'x86_64-w64-mingw32-'
       when 'x86-mingw32'
         'i686-w64-mingw32-'
+      when 'x86_64-linux'
+        'x86_64-linux-gnu-'
+      when 'x86-linux'
+        'i686-linux-gnu-'
       end) + name
   end
 
@@ -77,16 +89,32 @@ CrossRuby = Struct.new(:version, :host) {
   end
 
   def dlls
-    [
-      'kernel32.dll',
-      'msvcrt.dll',
-      'ws2_32.dll',
-      *(case
-        when ver >= '2.0.0'
-          'user32.dll'
-        end),
-      libruby_dll
-    ]
+    case platform
+      when /mingw32/
+      [
+        'kernel32.dll',
+        'msvcrt.dll',
+        'ws2_32.dll',
+        *(case
+          when ver >= '2.0.0'
+            'user32.dll'
+          end),
+        libruby_dll
+      ]
+      when /linux/
+      [
+        'libm.so.6',
+        'libpthread.so.0',
+        'libc.so.6',
+      ]
+    end
+  end
+
+  def dll_ref_versions
+    case platform
+      when /linux/
+        {"GLIBC"=>"2.17"}
+    end
   end
 }
 
@@ -312,14 +340,35 @@ Concourse.new("nokogiri").create_tasks!
 def verify_dll(dll, cross_ruby)
   dll_imports = cross_ruby.dlls
   dump = `#{['env', 'LANG=C', cross_ruby.tool('objdump'), '-p', dll].shelljoin}`
-  raise "unexpected file format for generated dll #{dll}" unless /file format #{Regexp.quote(cross_ruby.target)}\s/ === dump
-  raise "export function Init_nokogiri not in dll #{dll}" unless /Table.*\sInit_nokogiri\s/mi === dump
-
-  # Verify that the expected DLL dependencies match the actual dependencies
-  # and that no further dependencies exist.
-  dll_imports_is = dump.scan(/DLL Name: (.*)$/).map(&:first).map(&:downcase).uniq
-  if dll_imports_is.sort != dll_imports.sort
-    raise "unexpected dll imports #{dll_imports_is.inspect} in #{dll}"
+  if cross_ruby.windows?
+    raise "unexpected file format for generated dll #{dll}" unless /file format #{Regexp.quote(cross_ruby.target)}\s/ === dump
+    raise "export function Init_nokogiri not in dll #{dll}" unless /Table.*\sInit_nokogiri\s/mi === dump
+
+    # Verify that the expected DLL dependencies match the actual dependencies
+    # and that no further dependencies exist.
+    dll_imports_is = dump.scan(/DLL Name: (.*)$/).map(&:first).map(&:downcase).uniq
+    if dll_imports_is.sort != dll_imports.sort
+      raise "unexpected dll imports #{dll_imports_is.inspect} in #{dll}"
+    end
+  else
+    # Verify that the expected so dependencies match the actual dependencies
+    # and that no further dependencies exist.
+    dll_imports_is = dump.scan(/NEEDED\s+(.*)/).map(&:first).uniq
+    if dll_imports_is.sort != dll_imports.sort
+      raise "unexpected so imports #{dll_imports_is.inspect} in #{dll}"
+    end
+
+    # Verify that the expected so version requirements match the actual dependencies.
+    dll_ref_versions_list = dump.scan(/0x[\da-f]+ 0x[\da-f]+ \d+ (\w+)_([\d\.]+)$/i)
+    # Build a hash of library versions like {"LIBUDEV"=>"183", "GLIBC"=>"2.17"}
+    dll_ref_versions_is = dll_ref_versions_list.each.with_object({}) do |(lib, ver), h|
+      if !h[lib] || ver.split(".").map(&:to_i).pack("C*") > h[lib].split(".").map(&:to_i).pack("C*")
+        h[lib] = ver
+      end
+    end
+    if dll_ref_versions_is != cross_ruby.dll_ref_versions
+      raise "unexpected so version requirements #{dll_ref_versions_is.inspect} in #{dll}"
+    end
   end
   puts "#{dll}: Looks good!"
 end
@@ -339,8 +388,8 @@ task :cross do
   end
 end
 
-desc "build a windows gem without all the ceremony."
-task "gem:windows" do
+desc "build native fat binary gems for windows and linux"
+task "gem:native" do
   require "rake_compiler_dock"
   RakeCompilerDock.sh "bundle && rake cross native gem MAKE='nice make -j`nproc`' RUBY_CC_VERSION=#{ENV['RUBY_CC_VERSION']}"
 end

build_all

@@ -24,9 +24,9 @@ bundle exec rake clean clobber
 rm -rf gems
 mkdir -p gems
 
-# windows
-bundle exec rake gem:windows
-cp -v pkg/nokogiri*{x86,x64}-mingw32*.gem gems
+# windows and linux fat binary gems
+bundle exec rake gem:native
+cp -v pkg/nokogiri-*{x86,x64}*.gem gems
 
 # MRI
 bundle exec rake clean

ext/nokogiri/extconf.rb

@@ -480,50 +480,60 @@ def using_system_libraries?
           url: "http://zlib.net/fossils/#{recipe.name}-#{recipe.version}.tar.gz",
           sha256: dependencies["zlib"]["sha256"]
         }]
-      class << recipe
-        attr_accessor :cross_build_p
-
-        def configure
-          Dir.chdir work_path do
-            mk = File.read 'win32/Makefile.gcc'
-            File.open 'win32/Makefile.gcc', 'wb' do |f|
-              f.puts "BINARY_PATH = #{path}/bin"
-              f.puts "LIBRARY_PATH = #{path}/lib"
-              f.puts "INCLUDE_PATH = #{path}/include"
-              mk.sub!(/^PREFIX\s*=\s*$/, "PREFIX = #{host}-") if cross_build_p
-              f.puts mk
+      if windows?
+        class << recipe
+          attr_accessor :cross_build_p
+
+          def configure
+            Dir.chdir work_path do
+              mk = File.read 'win32/Makefile.gcc'
+              File.open 'win32/Makefile.gcc', 'wb' do |f|
+                f.puts "BINARY_PATH = #{path}/bin"
+                f.puts "LIBRARY_PATH = #{path}/lib"
+                f.puts "INCLUDE_PATH = #{path}/include"
+                mk.sub!(/^PREFIX\s*=\s*$/, "PREFIX = #{host}-") if cross_build_p
+                f.puts mk
+              end
             end
           end
-        end
 
-        def configured?
-          Dir.chdir work_path do
-            !! (File.read('win32/Makefile.gcc') =~ /^BINARY_PATH/)
+          def configured?
+            Dir.chdir work_path do
+              !! (File.read('win32/Makefile.gcc') =~ /^BINARY_PATH/)
+            end
           end
-        end
 
-        def compile
-          execute "compile", "make -f win32/Makefile.gcc"
-        end
+          def compile
+            execute "compile", "make -f win32/Makefile.gcc"
+          end
 
-        def install
-          execute "install", "make -f win32/Makefile.gcc install"
+          def install
+            execute "install", "make -f win32/Makefile.gcc install"
+          end
+        end
+        recipe.cross_build_p = cross_build_p
+      else
+        class << recipe
+          def configure
+            execute "configure", ["env", "CHOST=#{host}", "CFLAGS=-fPIC #{ENV['CFLAGS']}", "./configure", "--static", configure_prefix]
+          end
         end
       end
-      recipe.cross_build_p = cross_build_p
     end
 
-    libiconv_recipe = process_recipe("libiconv", dependencies["libiconv"]["version"], static_p, cross_build_p) do |recipe|
-      recipe.files = [{
-          url: "http://ftp.gnu.org/pub/gnu/libiconv/#{recipe.name}-#{recipe.version}.tar.gz",
-          sha256: dependencies["libiconv"]["sha256"]
-        }]
-      recipe.configure_options += [
-        "CPPFLAGS=-Wall",
-        "CFLAGS=-O2 -g",
-        "CXXFLAGS=-O2 -g",
-        "LDFLAGS="
-      ]
+    unless nix?
+      libiconv_recipe = process_recipe("libiconv", dependencies["libiconv"]["version"], static_p, cross_build_p) do |recipe|
+        recipe.files = [{
+            url: "http://ftp.gnu.org/pub/gnu/libiconv/#{recipe.name}-#{recipe.version}.tar.gz",
+            sha256: dependencies["libiconv"]["sha256"]
+          }]
+        recipe.configure_options += [
+          "CPPFLAGS=-Wall",
+          "CFLAGS=-O2 -g",
+          "CXXFLAGS=-O2 -g",
+          "LDFLAGS="
+        ]
+      end
     end
   else
     if darwin? && !have_header('iconv.h')