Date: Wed, 9 Aug 2000 12:51:12 -0400 From: Dan Moschuk <dan@FreeBSD.ORG> To: Greg Thompson <johnnyteardrop@hotmail.com> Cc: freebsd-hackers@FreeBSD.ORG, freebsd-net@FreeBSD.ORG Subject: Re: threadsafe name resolution Message-ID: <20000809125112.C293@spirit.jaded.net> In-Reply-To: <F3053sllNY30kkZIhTr000033b6@hotmail.com>; from johnnyteardrop@hotmail.com on Wed, Aug 09, 2000 at 10:40:27AM -0400 References: <F3053sllNY30kkZIhTr000033b6@hotmail.com>
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| i've just received confirmation from the author of the KAME resolution code | that it isn't at all thread safe: | | >Sure. As noted in name6.c, thread related stuff is not implemented yet. | >Since our resolver code based on bind4 doesn't aware thread safeness, | >all I can do now would be only putting mutex, anyway. | | sure enough, name6.c says: | | /* | * TODO for thread safe | * use mutex for _hostconf, _hostconf_init. | * rewrite resolvers to be thread safe | */ | | now, i'd say that it's fairly important for some form of threadsafe name | resolution to exist. until the KAME code is fixed, how about adding in the | ipv4 _r methods that have been discussed from time to time? or, at the very | least, put something in the manpage for getipnodebyname and friends | indicating that the funcs are not threadsafe. | | as you can probably tell, i wasted several hours worth of work bumping into | this problem. The problem lies deeper than that. Calls like gethostbyname() and friends are not threadsafe either, as they use an internal struct hostent and return a pointer to it (that another thread would happily clobber with its own data). Thread-happy functions we're supposed to be added by the Vixie people, and since I haven't checked up on it in about a year, they could be in there by now, but since we use BINDs name-resolver library, it's a contrib/ issue and our policy isn't to hack up the contrib/ tree. Of course, the door is always open for you to write the code and submit it to the bind team. 8) -Dan -- Man is a rational animal who always loses his temper when he is called upon to act in accordance with the dictates of reason. -- Oscar Wilde To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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