May 2006 - Darwin-dev - lists.apple.com

Re: Equivalent of gethostbyname_r for Mac OS X?
by Marc Majka 03 May '06

03 May '06

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com -- Marc Majka _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… The following routines are all thread-safe. You may safely ignore comments in the man pages that suggest otherwise. - alias_getbyname alias_getent alias_setent alias_endent - bootp_getbyether bootp_getbyip - bootparams_getbyname bootparams_getent bootparams_setent bootparams_endent - getfsbyname getfsspec getfsfile getfsent setfsent endfsent - initgroups getgrnam getgrgid getgrent setgrent endgrent - gethostbyaddr gethostbyname gethostbyname2 gethostent sethostent endhostent - getipnodebyname getipnodebyaddr - innetgr getnetgrent setnetgrent endnetgrent - getnetbyaddr getnetbyname getnetent setnetent endnetent - prdb_getbyname prdb_get prdb_set prdb_end - getprotobyname getprotobynumber getprotoent setprotoent endprotoent - getrpcbyname getrpcbynumber getrpcent setrpcent endrpcent - getservbyport getservbyname getservent setservent endservent - getpwnam getpwuid getpwent setpwent endpwent They all cache returned data in per-thread storage. The threads correctly release the cached structures on subsequent calls. Memory is reclaimed when threads exit by a destructor routine. For those with an interest in seeing the implementation, see the lu_utils.[ch] files and any one of the lu_*.c routines (e.g. lu_host.c) in the Libinfo project: http://www.opensource.apple.com/darwinsource/ 10.4.6.ppc/Libinfo-222.1/lookup.subproj/lu_host.c This email sent to site_archiver(a)lists.apple.com

1 0

Re: Equivalent of gethostbyname_r for Mac OS X?
by Shawn Erickson 03 May '06

03 May '06

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Domainkey-signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=uHQ3r2ibfBTqlUkFtU6twVRufkr34aQ4AbSAIVjSYO3qnG3/vcCeH6Fbe6VpqZ9fzmhiE6EsKTi8DX5zcTY67JzGPkOd7iq8KtmXnWV+2YAhxx3duGUZaPBshZUP1hp5JACkD8LQouNNmXlTWqtny7N4aBxNvoO5atH6OokOQEY= Pelle Johansson wrote: > > 3 maj 2006 kl. 07.12 skrev Dale Walsh: > >> I was thinking a little more, I was doing the following in code >> because this function is supposed to be thread-safe (getaddrinfo). > > Unfortunately, while it's supposed to be thread-safe, it currently > isn't. That's noted in the BUGS section of the manpage. > I otherwise recommend to use it whenever possible. > --Pelle Johansson > Hey Pelle, In regard to gethostbyaddr and getaddrinfo, which function are you saying is not thread safe? [0:777] > man getaddrinfo ... BUGS The implementation of getaddrinfo() is not thread-safe. BSD December 20, 2004 BSD [0:778] > man gethostbyname ... BUGS These functions use static data storage; if the data is needed for future use, it should be copied before any subsequent calls overwrite it. Only the Internet address format is currently understood. BSD May 25, 1995 BSD ...however I am not sure how fully up-to-date the man pages really are (the above are from a 10.4 system). -Shawn _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… On 5/3/06, Tron Thomas <tron.thomas(a)verizon.net> wrote: This email sent to site_archiver(a)lists.apple.com

1 0

Re: Equivalent of gethostbyname_r for Mac OS X?
by Tron Thomas 03 May '06

03 May '06

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com User-agent: Thunderbird 1.5.0.2 (Windows/20060308) 3 maj 2006 kl. 07.12 skrev Dale Walsh: _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… Pelle Johansson wrote: I was thinking a little more, I was doing the following in code because this function is supposed to be thread-safe (getaddrinfo). Unfortunately, while it's supposed to be thread-safe, it currently isn't. That's noted in the BUGS section of the manpage. I otherwise recommend to use it whenever possible. --Pelle Johansson Hey Pelle, In regard to gethostbyaddr and getaddrinfo, which function are you saying is not thread safe? This email sent to site_archiver(a)lists.apple.com

1 0

Re: Equivalent of gethostbyname_r for Mac OS X?
by Pelle Johansson 03 May '06

03 May '06

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com 3 maj 2006 kl. 07.12 skrev Dale Walsh: _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… I was thinking a little more, I was doing the following in code because this function is supposed to be thread-safe (getaddrinfo). Unfortunately, while it's supposed to be thread-safe, it currently isn't. That's noted in the BUGS section of the manpage. I otherwise recommend to use it whenever possible. -- Pelle Johansson This email sent to site_archiver(a)lists.apple.com

1 0

Re: Equivalent of gethostbyname_r for Mac OS X?
by Alexey Proskuryakov 03 May '06

03 May '06

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Thread-index: AcZuj3k8t8MYw9qCEdqjOgADk8DT5g== Thread-topic: Equivalent of gethostbyname_r for Mac OS X? User-agent: Microsoft-Entourage/11.2.3.060209 On 03.05.2006 05:18, "Tron Thomas" <tron.thomas(a)verizon.net> wrote: > I work on a cross platform project that is multithreaded. The code > base wants to call gethostbyname_r as a thread safe way of connecting > to a host sever. However, this function is not supported on Mac OS > X. What is the equivalent thread safe way to accomplish the same > functionality? This isn't documented AFAIK, but Darwin gethostbyname uses thread local storage, and is thus thread safe. Last time when this topic was discussed here, an Apple employee mentioned that there already was a Radar to fix the man page. ----------------------------------------------- The Mac OS X implementations of a number of routines found in libSystem, including getpwnam and getpwuid, have been modified to be thread-safe. Rather than returning a pointer to a static data structure, these routines allocate a structure for the returned value that is stored in thread-specific memory. The memory is recycled (by each thread) every time you make a call to one of these routines. That allows you to use these APIs safely in multi-threaded applications. The specific routines in the Libinfo project (see Libinfo/ lookup.subproj/lu_*.c) that maintain thread-specific memory for results are: - alias_getbyname alias_getent alias_setent alias_endent - bootp_getbyether bootp_getbyip - bootparams_getbyname bootparams_getent bootparams_setent bootparams_endent - getfsbyname getfsspec getfsfile getfsent setfsent endfsent - initgroups getgrnam getgrgid getgrent setgrent endgrent - gethostbyaddr gethostbyname gethostbyname2 gethostent sethostent endhostent - getipnodebyname getipnodebyaddr - innetgr getnetgrent setnetgrent endnetgrent - getnetbyaddr getnetbyname getnetent setnetent endnetent - prdb_getbyname prdb_get prdb_set prdb_end - getprotobyname getprotobynumber getprotoent setprotoent endprotoent - getrpcbyname getrpcbynumber getrpcent setrpcent endrpcent - getservbyport getservbyname getservent setservent endservent - getpwnam getpwuid getpwent setpwent endpwent ----------------------------------------------- - WBR, Alexey Proskuryakov _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

1 0

Re: Equivalent of gethostbyname_r for Mac OS X?
by Dale Walsh 03 May '06

03 May '06

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Mta-interface: amavisd-new-2.3.3 (2005-08-22) + Maia Mailguard 1.1.0 at daleenterprise.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com PGP.sig

1 0

Re: Equivalent of gethostbyname_r for Mac OS X?
by Tron Thomas 03 May '06

03 May '06

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com User-agent: Thunderbird 1.5.0.2 (Windows/20060308) On May 2, 2006, at 21:18 , Tron Thomas wrote: _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… I know that gethostbyname is not re-entrant. That is why I was asking if there was another re-entrant alternative that could be used. What is the reason there is no re-entrant equivalent for gethostbyname? Dale Walsh wrote: I work on a cross platform project that is multithreaded. The code base wants to call gethostbyname_r as a thread safe way of connecting to a host sever. However, this function is not supported on Mac OS X. What is the equivalent thread safe way to accomplish the same functionality? The gethostbyname_r function can be replaced with gethostbyname, which is similar except that it is non-reentrant. Replacing a reentrant function with a non-reentrant function is not a favored alternative, as it can cause unpredictable and hard-to-trace bugs if the calling function doesn't terminate the call appropriately and take into consideration that the call itself might time out which would result in unpredictable behavior if this returned data is not tested/validated. _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com <mailto:Darwin-dev@lists.apple.com>) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/dale%40daleenterprise.com This email sent to dale(a)daleenterprise.com <mailto:dale@daleenterprise.com> This email sent to site_archiver(a)lists.apple.com

1 0

Re: Equivalent of gethostbyname_r for Mac OS X?
by Dale Walsh 03 May '06

03 May '06

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Mta-interface: amavisd-new-2.3.3 (2005-08-22) + Maia Mailguard 1.1.0 at daleenterprise.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com PGP.sig

1 0

Equivalent of gethostbyname_r for Mac OS X?
by Tron Thomas 03 May '06

03 May '06

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com User-agent: Thunderbird 1.5.0.2 (Windows/20060308) _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… I work on a cross platform project that is multithreaded. The code base wants to call gethostbyname_r as a thread safe way of connecting to a host sever. However, this function is not supported on Mac OS X. What is the equivalent thread safe way to accomplish the same functionality? This email sent to site_archiver(a)lists.apple.com

1 0