In ELFShim, #needed_libraries, #dynamic_elf? and #with_interpreter? check using patchelf gem.

Having HOMEBREW_PATCHELF_RB set in the ENV,
will conditionally install patchelf.rb gem,
use patchelf.rb in the above mentioned methods.
The installed vendored gems are listed in .gitignore
to maintain a clean state.

.gitignore

@@ -129,9 +129,6 @@
 **/vendor/bundle/ruby/*/gems/simplecov-*/
 **/vendor/bundle/ruby/*/gems/simplecov-cobertura-*/
 **/vendor/bundle/ruby/*/gems/simplecov-html-*/
-**/vendor/bundle/ruby/*/gems/sorbet-*/
-**/vendor/bundle/ruby/*/gems/sorbet-runtime-*/
-**/vendor/bundle/ruby/*/gems/tapioca-*/
 **/vendor/bundle/ruby/*/gems/term-ansicolor-*/
 **/vendor/bundle/ruby/*/gems/thor-*/
 **/vendor/bundle/ruby/*/gems/tins-*/
@@ -140,6 +137,14 @@
 **/vendor/bundle/ruby/*/gems/unicode-display_width-*/
 **/vendor/bundle/ruby/*/gems/webrobots-*/
 
+# Ignore conditional dependencies we don't wish to vendor
+**/vendor/bundle/ruby/*/gems/bindata-*/
+**/vendor/bundle/ruby/*/gems/elftools-*/
+**/vendor/bundle/ruby/*/gems/patchelf-*/
+**/vendor/bundle/ruby/*/gems/sorbet-*/
+**/vendor/bundle/ruby/*/gems/sorbet-runtime-*/
+**/vendor/bundle/ruby/*/gems/tapioca-*/
+
 # Ignore `bin` contents (again).
 /bin
 

Library/Homebrew/Gemfile

@@ -23,6 +23,7 @@ end
 gem "activesupport"
 gem "concurrent-ruby"
 gem "mechanize"
+gem "patchelf" if ENV["HOMEBREW_PATCHELF_RB"]
 gem "plist"
 gem "rubocop-performance"
 gem "rubocop-rspec"

Library/Homebrew/os/linux/elf.rb

@@ -74,7 +74,14 @@ module ELFShim
     @with_interpreter = if binary_executable?
       true
     elsif dylib?
-      if which "readelf"
+      if HOMEBREW_PATCHELF_RB
+        begin
+          patchelf_patcher.interpreter.present?
+        rescue PatchELF::PatchError => e
+          opoo e
+          false
+        end
+      elsif which "readelf"
         Utils.popen_read("readelf", "-l", to_path).include?(" INTERP ")
       elsif which "file"
         Utils.popen_read("file", "-L", "-b", to_path).include?(" interpreter ")
@@ -89,7 +96,9 @@ module ELFShim
   def dynamic_elf?
     return @dynamic_elf if defined? @dynamic_elf
 
-    @dynamic_elf = if which "readelf"
+    @dynamic_elf = if HOMEBREW_PATCHELF_RB
+      patchelf_patcher.instance_variable_get(:@elf).segment_by_type(:DYNAMIC).present?
+    elsif which "readelf"
       Utils.popen_read("readelf", "-l", to_path).include?(" DYNAMIC ")
     elsif which "file"
       !Utils.popen_read("file", "-L", "-b", to_path)[/dynamic|shared/].nil?
@@ -127,7 +136,9 @@ module ELFShim
     private
 
     def needed_libraries(path)
-      if DevelopmentTools.locate "readelf"
+      if HOMEBREW_PATCHELF_RB
+        needed_libraries_using_patchelf_rb path
+      elsif DevelopmentTools.locate "readelf"
         needed_libraries_using_readelf path
       elsif DevelopmentTools.locate "patchelf"
         needed_libraries_using_patchelf path
@@ -138,6 +149,25 @@ module ELFShim
       end
     end
 
+    def needed_libraries_using_patchelf_rb(path)
+      patcher = path.patchelf_patcher
+      return [nil, []] unless patcher
+
+      soname = begin
+        patcher.soname
+      rescue PatchELF::PatchError => e
+        opoo e unless e.to_s.start_with? "Entry DT_SONAME not found, not a shared library?"
+        nil
+      end
+      needed = begin
+        patcher.needed
+      rescue PatchELF::PatchError => e
+        opoo e
+        []
+      end
+      [soname, needed]
+    end
+
     def needed_libraries_using_patchelf(path)
       return [nil, []] unless path.dynamic_elf?
 
@@ -172,6 +202,16 @@ module ELFShim
     end
   end
 
+  def patchelf_patcher
+    return unless HOMEBREW_PATCHELF_RB
+
+    @patchelf_patcher ||= begin
+      Homebrew.install_bundler_gems!
+      require "patchelf"
+      PatchELF::Patcher.new to_s, logging: false
+    end
+  end
+
   def metadata
     @metadata ||= Metadata.new(self)
   end

Library/Homebrew/os/linux/global.rb

@@ -1,5 +1,8 @@
 # frozen_string_literal: true
 
+# enables experimental readelf.rb, patchelf support.
+HOMEBREW_PATCHELF_RB = ENV["HOMEBREW_PATCHELF_RB"].present?.freeze
+
 module Homebrew
   DEFAULT_PREFIX ||= if Homebrew::EnvConfig.force_homebrew_on_linux?
     HOMEBREW_DEFAULT_PREFIX