You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: linux_injectsyscall.rb
    path of file: ./repos/grinder/node/lib/metasm/samples
    
    the code of the file until where you have to start completion: #!/usr/bin/ruby

#    This file is part of Metasm, the Ruby assembly manipulation suite
#    Copyright (C) 2006-2009 Yoann GUILLOT
#
#    Licence is LGPL, see LICENCE in the top-level directory

#
# this exemple illustrates the use of the PTrace class to hijack a syscall in a running process
# the next syscall made is patched to run the syscall with the arguments of our choice, then
# run the original intended sysc
    
	def inject(sysnr, *args)
		sysnr = syscallnr[sysnr] || sysnr

		syscall
		puts '[*] waiting syscall'
		Process.waitpid(@pid)

		savedctx = CTX.inject({}) { |ctx, reg| ctx.update reg => peekusr(REGS_I386[reg]) }

		eip = (savedctx['EIP'] - 2) & 0xffffffff
		fu = readmem(eip, 2)
		if fu == "\xcd\x80"
			mode = :int80
		elsif fu == "\xeb\xf3" and readmem(eip-14, 7).unpack('H*').first == "51525589e50f34"	# aoenthuasn
			mode = :sysenter
		elsif fu == "\x0f\x05"
			mode = :syscall
		else
			puts 'unhandled syscall convention, aborting, code = ' + readmem(eip-4, 8).unpack('H*').first
			cont
			return self
		end