Getaddrinfo() on glibc calls getenv(), oh boy

Re:Getaddrinfo() on glibc calls getenv(), oh boy by LoganDark on Monday October 16, 2023 @09:13PM (#37909028)

getaddrinfo is terrible. Did you know it also opens and then connects to a socket? Any process that uses getaddrinfo needs a blanket exception in my firewall in order to work properly, because otherwise it will fail to connect to some randomly-generated port that it just made up.

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Re:Getaddrinfo() on glibc calls getenv(), oh boy by tedunangst on Monday October 16, 2023 @09:25PM (#37909155)

What should I use instead that doesn't open a socket?

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Re:Getaddrinfo() on glibc calls getenv(), oh boy by hknapp on Monday October 16, 2023 @09:35PM (#37909256)

They probably could have given a more apt name

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Re:Getaddrinfo() on glibc calls getenv(), oh boy by Sprocklem on Monday October 16, 2023 @09:53PM (#37909440)

How do you propose that DNS resolution precede without opening a socket?

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Re:Getaddrinfo() on glibc calls getenv(), oh boy by nomadluap on Monday October 16, 2023 @10:49PM (#37909929)

For one thing, it could delegate to a local service. Granted, the communication to this service is probably still be over a socket interface, but at least as a purely-local connection you would hopefully have some better worst-case performance characteristics.

This is basically what dnsmasq does when you use it as a local DNS cache.

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Re:Getaddrinfo() on glibc calls getenv(), oh boy by kccqzy on Monday October 16, 2023 @11:20PM (#37910161)

Completely agree. Just use systemd-resolved which is the recommended way of doing DNS anyway.

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Re:Getaddrinfo() on glibc calls getenv(), oh boy by guappa on Tuesday October 17, 2023 @03:25AM (#37911659)

And how do you communicate with systemd-resolved?

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Re:Getaddrinfo() on glibc calls getenv(), oh boy by mambru on Tuesday October 17, 2023 @05:16AM (#37912394)

Via DBus:

https://www.freedesktop.org/software/systemd/man/org.freedes...

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Re:Getaddrinfo() on glibc calls getenv(), oh boy by guappa on Tuesday October 17, 2023 @09:27AM (#37914692)

dbus is just a protocol that needs something else to actually transfer the data.

Normally, that's a socket in /run/dbus/system_bus_socket

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Re:Getaddrinfo() on glibc calls getenv(), oh boy by kccqzy on Tuesday October 17, 2023 @01:09PM (#37918176)

And guess what. A UNIX socket does not use DNS or the damned getaddrinfo() function that's the ire of the article.

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Re:Getaddrinfo() on glibc calls getenv(), oh boy by LoganDark on Monday October 16, 2023 @11:54PM (#37910392)

It opens a socket to the same process that called getaddrinfo. That is, it's just communicating with itself, using a brand-new randomly-generated port for each call. This should be completely unnecessary.

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Re:Getaddrinfo() on glibc calls getenv(), oh boy by JackSlateur on Tuesday October 17, 2023 @08:18AM (#37913824)

So, I have a program that does getaddrinfo(3) and nothing more, and this program setup a socket, listen(2) to it, create another socket and connect with it to the first one ?

This looks insane and not what strace(1) tells me

Could you give me more details ?

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Re:Getaddrinfo() on glibc calls getenv(), oh boy by LoganDark on Tuesday October 17, 2023 @05:13PM (#37921657)

I didn't know glibc didn't do the same thing. `getaddrinfo()` on Windows seems to do this because randomly a program will try to connect to `::1:59962` or something, and if I don't allow it in my firewall, it will start whining that some getaddrinfo thread failed to start. This has happened across all sorts of different programs. It's infuriating.

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