89 lines
2 KiB
Ruby
89 lines
2 KiB
Ruby
require 'fiddle'
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require 'fiddle/import'
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require 'io/extra'
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class NS
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extend Fiddle::Importer
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dlload Fiddle.dlopen( nil)
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SetNS_Function = Fiddle::Function.new handler['setns'], [Fiddle::TYPE_VOIDP, Fiddle::TYPE_VOIDP], Fiddle::TYPE_INT
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class <<self
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def setns fd, t
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r = SetNS_Function.call fd.to_i, t.to_i
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SystemCallError.new "setns(#{fd.to_i})", Fiddle.last_error if -1 == r
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r
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end
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def _open_nsfd pid, type
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File.open "/proc/%d/ns/%s" % [pid, type]
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end
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def open pid, *types, &exe
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ns = new pid, *types
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if block_given?
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begin yield ns
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ensure ns.close
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end
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else ns
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end
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end
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def change pid, *types, &exe
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open pid, *types do |ns|
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ns.change &exe
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end
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end
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def enter pid, keep_open: nil
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new( pid).enter keep_open: keep_open
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end
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end
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attr_reader :pid, :fds
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def initialize pid, *types
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@pid, @fds = pid, {}
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types = Dir.children "/proc/%d/ns" % pid if types.empty? or types.include?( :any)
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types.each {|t| @fds[t.to_sym] = self.class._open_nsfd pid, t }
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end
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def close_ios *keep_open
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keep_open =
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keep_open.flatten.map do |fd|
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case fd
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when Integer then fd
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when IO then fd.to_i
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when nil # ignore
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else raise ArgumentError, "Unknown file descriptor for keeping opened: #{fd.inspect}"
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end
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end.sort
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IO.fdwalk(0) {|fd| fd.close unless keep_open.include? fd.to_i }
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end
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def enter keep_open: nil
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close_ios keep_open, @fds.values
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@fds.each {|_, fd| self.class.setns fd, 0 }
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close
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nil
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end
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def close
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@fds.each {|_, fd| fd.close }
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end
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def change &block
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if block_given?
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@owns = @fds.map {|ns, _f| self.class._open_nsfd $$, ns }
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begin
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@fds.each {|type, fd| self.class.setns fd, 0 }
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yield
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ensure
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@owns.each {|fd| self.class.setns fd, 0 }
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end
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else
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@fds.each {|type, fd| self.class.setns fd, 0 }
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nil
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end
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end
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end
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