1 files changed, 114 insertions, 0 deletions
diff --git a/lib/bundler/cli/exec.rb b/lib/bundler/cli/exec.rb
new file mode 100644
index 0000000000..2fdc416286
--- /dev/null
+++ b/lib/bundler/cli/exec.rb
@@ -0,0 +1,114 @@
+# frozen_string_literal: true
+
+require_relative "../current_ruby"
+
+module Bundler
+  class CLI::Exec
+    attr_reader :options, :args, :cmd
+
+    TRAPPED_SIGNALS = %w[INT].freeze
+
+    def initialize(options, args)
+      @options = options
+      @cmd = args.shift
+      @args = args
+      @args << { close_others: !options.keep_file_descriptors? } unless Bundler.current_ruby.jruby?
+    end
+
+    def run
+      validate_cmd!
+      SharedHelpers.set_bundle_environment
+      if bin_path = Bundler.which(cmd)
+        if !Bundler.settings[:disable_exec_load] && directly_loadable?(bin_path)
+          bin_path.delete_suffix!(".bat") if Gem.win_platform?
+          kernel_load(bin_path, *args)
+        else
+          bin_path = "./" + bin_path unless File.absolute_path?(bin_path)
+          kernel_exec(bin_path, *args)
+        end
+      else
+        # exec using the given command
+        kernel_exec(cmd, *args)
+      end
+    end
+
+    private
+
+    def validate_cmd!
+      return unless cmd.nil?
+      Bundler.ui.error "bundler: exec needs a command to run"
+      exit 128
+    end
+
+    def kernel_exec(*args)
+      Kernel.exec(*args)
+    rescue Errno::EACCES, Errno::ENOEXEC
+      Bundler.ui.error "bundler: not executable: #{cmd}"
+      exit 126
+    rescue Errno::ENOENT
+      Bundler.ui.error "bundler: command not found: #{cmd}"
+      Bundler.ui.warn "Install missing gem executables with `bundle install`"
+      exit 127
+    end
+
+    def kernel_load(file, *args)
+      args.pop if args.last.is_a?(Hash)
+      ARGV.replace(args)
+      $0 = file
+      Process.setproctitle(process_title(file, args)) if Process.respond_to?(:setproctitle)
+      require_relative "../setup"
+      TRAPPED_SIGNALS.each {|s| trap(s, "DEFAULT") }
+      Kernel.load(file)
+    rescue SystemExit, SignalException
+      raise
+    rescue Exception # rubocop:disable Lint/RescueException
+      Bundler.ui.error "bundler: failed to load command: #{cmd} (#{file})"
+      Bundler::FriendlyErrors.disable!
+      raise
+    end
+
+    def process_title(file, args)
+      "#{file} #{args.join(" ")}".strip
+    end
+
+    def directly_loadable?(file)
+      if Gem.win_platform?
+        script_wrapper?(file)
+      else
+        ruby_shebang?(file)
+      end
+    end
+
+    def script_wrapper?(file)
+      script_file = file.delete_suffix(".bat")
+      return false unless File.exist?(script_file)
+
+      if File.zero?(script_file)
+        Bundler.ui.warn "#{script_file} is empty"
+        return false
+      end
+
+      header = File.open(file, "r") {|f| f.read(32) }
+      ruby_exe = "#{RbConfig::CONFIG["RUBY_INSTALL_NAME"]}#{RbConfig::CONFIG["EXEEXT"]}"
+      ruby_exe = "ruby.exe" if ruby_exe.empty?
+      header.include?(ruby_exe)
+    end
+
+    def ruby_shebang?(file)
+      possibilities = [
+        "#!/usr/bin/env ruby\n",
+        "#!/usr/bin/env jruby\n",
+        "#!/usr/bin/env truffleruby\n",
+        "#!#{Gem.ruby}\n",
+      ]
+
+      if File.zero?(file)
+        Bundler.ui.warn "#{file} is empty"
+        return false
+      end
+
+      first_line = File.open(file, "rb") {|f| f.read(possibilities.map(&:size).max) }
+      possibilities.any? {|shebang| first_line.start_with?(shebang) }
+    end
+  end
+end