82 lines
2.4 KiB
Ruby
82 lines
2.4 KiB
Ruby
require 'timeout'
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module Rex
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###
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#
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# This module provides a set of methods for performing various blocking
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# operations in a manner that is compatible with ruby style threads.
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#
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###
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module ThreadSafe
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DefaultCycle = 0.2
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#
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# Wraps calls to select with a lower timeout period and does the
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# calculations to walk down to zero timeout. This has a little room for
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# improvement in that it should probably check how much time actually
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# elapsed during the select call considering ruby threading wont be exactly
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# accurate perhaps.
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#
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def self.select(rfd = nil, wfd = nil, efd = nil, t = nil)
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left = t
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# Immediately raise a StreamClosedError if the socket was closed. This
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# prevents a bad fd from being passed downstream and solves an issue
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# with Ruby on Windows.
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rfd.each { |fd| raise StreamClosedError.new(fd) if (fd.closed?) } if rfd
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begin
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orig_size = rfd.length if (rfd)
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# Poll the set supplied to us at least once.
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begin
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rv = ::IO.select(rfd, wfd, efd, DefaultCycle)
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rescue ::IOError, ::Errno::EBADF, ::Errno::ENOTSOCK
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# If a stream was detected as being closed, re-raise the error as
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# a StreamClosedError with the specific file descriptor that was
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# detected as being closed. This is to better handle the case of
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# a closed socket being detected so that it can be cleaned up and
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# removed.
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rfd.each { |fd| raise StreamClosedError.new(fd) if (fd.closed?) } if rfd
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# If the original rfd length is not the same as the current
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# length, then the list may have been altered and as such may not
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# contain the socket that caused the IOError. This is a bad way
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# to do this since it's possible that the array length could be
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# back to the size that it was originally and yet have had the
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# socket that caused the IOError to be removed.
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return nil if (rfd and rfd.length != orig_size)
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# Re-raise the exception since we didn't handle it here.
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raise $!
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# rescue ::Exception => e
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# $stderr.puts "SELECT(#{t}) #{[rfd,wfd,efd].inspect} #{e.class} #{e} #{e.backtrace}"
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end
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return rv if (rv)
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# Decrement the amount of time left by the polling cycle
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left -= DefaultCycle if (left)
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# Keep chugging until we run out of time, if time was supplied.
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end while ((left == nil) or (left > 0))
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# Nothin.
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nil
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end
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#
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# Simulates a sleep operation by selecting on nil until a timeout period
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# expires.
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#
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def self.sleep(seconds)
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self.select(nil, nil, nil, seconds)
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seconds
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end
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end
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end |