[squeak-dev] Bug in FTPClient

Nicolas Cellier nicolas.cellier.aka.nice at gmail.com
Wed May 13 10:02:34 UTC 2009


There are two bugs in this code:
lookForCode: code ifDifferent: handleBlock
	"We are expecting a certain numeric code next.
	However, in the FTP protocol, multiple lines are allowed.
	If the response is multi-line, the fourth character of the first line is a
	$- and the last line repeats the numeric code but the code is followed by
	a space. So it's possible that there are more lines left of the last
response that
	we need to throw away. We use peekForAll: so that we don't discard the
	next response that is not a continuation line."

	| headToDiscard |
	"check for multi-line response"
	(self lastResponse size > 3
			and: [(self lastResponse at: 4) = $-])
		ifTrue: ["Discard continuation lines."
			[headToDiscard _ self lastResponse first: 4.
			[[self stream peekForAll: headToDiscard]
				whileTrue: [self stream nextLine]]
				on: Exception
				do: [:ex | ^handleBlock value: nil]]].
	^ super lookForCode: code ifDifferent: handleBlock

1) it attempts to catch Exception, which is generally a bad idea.
Error would be more appropriated.
2) but the whole ifTrue: conditions is a no-op: it simply creates a
block that is not used.
Maybe intention was:
		ifTrue: ["Discard continuation lines."
			headToDiscard := self lastResponse first: 4.
			[[self stream peekForAll: headToDiscard]
				whileTrue: [self stream nextLine]]
				on: Exception
				do: [:ex | ^handleBlock value: nil]].

Is this code used?



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