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Dynamic linking

drewdevault.com

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Re: Dynamic linking

#41

Post by mforney »

loeg wrote: post #27
mforney wrote: post #20

Earlier quoted context omitted.

I don't think stali has seen any activity in several years. As far as I know, the only completely statically linked Linux distribution that is actively developed is my own project (inspired by stali), oasis: https://github.com/oasislinux/oasis

Do you static-link Linux? :-)

I'm not sure what you mean here. Are you asking whether I build my kernel drivers as modules or built-in? Personally, I build my kernels without modules, but I've never heard of that technique being called "static-linking Linux".

Re: Dynamic linking

#42

Post by pengaru »

Back in the 90s we'd statically link the most frequently executed programs on busy servers for a significant performance boost.

Dynamic linking is not a performance feature, it's a decoupling feature.

Re: Dynamic linking

#43

Post by cryptonector »

cryptonector wrote: post #23

By far the most important reason for dynamic linking for C is semantics: static linking semantics are stuck in 1978 and suck (more on that below), while dynamic linking semantics make C a much better language. In particular, static linking for C has two serious problems: 1. symbol collisions -> accidental interposition (and crashes); 2. you have to flatten the dependency tree into a topological sort at the final link…

In a containerized world, static linking will generally be faster, unless the OS does page de-duping for text/rodata. So doing the work to make static linking semantics not suck seems likely to be important.

Re: Dynamic linking

#44

Post by wahern »

eeereerews wrote: post #36
rumanator wrote: post #19

Earlier quoted context omitted.

> Dynamically linking against something in the long tail is pretty pointless though. I disagree. Dynamic linking, in the context of an OS which offers a curated list of packages in the form of an official package repository, means that a specialized third party is able to maintain a subcomponent of your system. This means you and me and countless others are able to reap the benefit of bugfixes and security fixes prov…

It can also cut the other way though. Bugs can be introduced, compatibility can be broken, users can not find the library in their package manager, or they may find too new of a version. The danger of this is smaller for popular libraries, but goes up as you move to the long tail.

But this also highlights the benefit of community packaging. Debian packagers often backport security fixes into older versions of libraries that are no longer maintained upstream. That's a big part of their job--not just to bang out a build and walk away, but to keep an eye on things. This is why it's important to only use distro-packaged libraries as much as you can, even when statically linking.

Getting off the treadmill of integrating interface-breaking upstream changes is one of the biggest practical reasons people prefer static linking and directly adding upstream source repositories into their build. It's at least as important, IME, as being able to use newer versions of libraries unavailable in an LTS distro. It can work well for large organizations, such as Google with their monolithic build, because they can and often do substitute the army of open source packers with their own army of people to curate and backport upstream changes. For everybody else it's quite risky, and if containerization provides any measure we're definitely worse off given the staleness problems with even the most popular containers.[1]

[1] I wouldn't be surprised if an open source project emerged to provide regularly rebuilt and possibly patched upstream containers, recapitulating the organizational evolution of the traditional FOSS distribution ecosystem.

Re: Dynamic linking

#45

Post by monocasa »

wahern wrote: post #18
monocasa wrote: post #7

Earlier quoted context omitted.

I imagine there's some way to, because the kernel is able to apply ASLR to the dynamic linker itself.

It's not a matter of possible, but whether the work has been done throughout the toolchain and runtime stacks. When OpenBSD implemented static PIE, -static and -pie, the literal options and the code generation aspects more generally, were still mutually exclusive in GCC and clang. GCC required patching to enable both static linking and PIE generation. In fact, my local GCC 9.3 man page still says that -static overrid…

For sure. My comment was directed at Linux the kernel rather than Linux the ecosystem, but it's a totally valid point that for practical purposes that distinction can border on meaningless.

Re: Dynamic linking

#46

Post by BeetleB »

dwheeler wrote: post #28

Not convinced. First, this analysis was done on Arch Linux, a source-based distribution. Since you know at compile time what your environment is, I would expect the benefits to be smaller. And of course, this means you're willing to do a lot of recompiles. I'd like to see analysis done on more traditional (& common) binary distros. Second, the arguments seem a little cherry-picked. "Over half of your libraries are us…

> First, this analysis was done on Arch Linux, a source-based distribution. Since you know at compile time what your environment is, I would expect the benefits to be smaller. And of course, this means you're willing to do a lot of recompiles.

I run Gentoo as my Linux box. It takes a long time to compile stuff as it is (and I have a 22 core machine). Being forced to compile a lot more because everything is linked statically would be a nightmare.

This is definitely not a plus for source based distributions.

Re: Dynamic linking

#48

Post by cryptonector »

k__ wrote: post #47
cryptonector wrote: post #35

Earlier quoted context omitted.

https://news.ycombinator.com/item?id=23656173

Are these also issues for languages like Go and Rust?

No, not for Rust, and not for Goland, IIRC. The reason is that they have proper namespacing functionality in the language, and generally modern languages record dependency metadata in the direct dependents.

This is strictly a C problem.

Re: Dynamic linking

#49

Post by bjourne »

BeetleB wrote: post #46
dwheeler wrote: post #28

Not convinced. First, this analysis was done on Arch Linux, a source-based distribution. Since you know at compile time what your environment is, I would expect the benefits to be smaller. And of course, this means you're willing to do a lot of recompiles. I'd like to see analysis done on more traditional (& common) binary distros. Second, the arguments seem a little cherry-picked. "Over half of your libraries are us…

> First, this analysis was done on Arch Linux, a source-based distribution. Since you know at compile time what your environment is, I would expect the benefits to be smaller. And of course, this means you're willing to do a lot of recompiles. I run Gentoo as my Linux box. It takes a long time to compile stuff as it is (and I have a 22 core machine). Being forced to compile a lot more because everything is linked sta…

Running Gentoo and complaining about long compile times is like cutting off your leg and complaining that walking hurts.

Re: Dynamic linking

#50

Post by riquito »

eeereerews wrote: post #37
dwheeler wrote: post #28

Not convinced. First, this analysis was done on Arch Linux, a source-based distribution. Since you know at compile time what your environment is, I would expect the benefits to be smaller. And of course, this means you're willing to do a lot of recompiles. I'd like to see analysis done on more traditional (& common) binary distros. Second, the arguments seem a little cherry-picked. "Over half of your libraries are us…

What do you mean by "source-based distribution"?

One without packages shipped as prebuilt binaries: Gentoo [1] would be a good example. You compile every binary yourself (sometime you can use prebuilt binaries for the biggest software, if you are so inclined and the distro allows it).

[1] https://www.gentoo.org/

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