Oasis – a small, statically-linked Linux system
github.com
github.com
I had the plan to build oasis with bazel for some immutable OS images that could run as kubernetes nodes. I succeeded with a little pointing.
I also have a small, but burning, passion for reproducible builds, distributed compilation and distributed caching.
Being able to build an entire OS and essentially anything I want on top in a reproducible and relatively organic way (with incremental compilation) is pretty dope.
But you speak from sufficient experience that I presume Nix is a “been there, done that” thing for you. What gives?
Memorizing isn’t a term I’m familiar with in this context.
I am interested in making a system that can memoize large databases from ETL systems and then serve that on iroh or ipfs/torrent, such that a process that may take a supercomputer a week to process can have the same code run on a laptop and it will notice it's been done my a university supercomputer before already and grab that result automatically from the decentralized network of all people using the software (who downloaded the ETL database).
That way you save compute and time.
Yes, absolutely doable in Nix.
Derivations are just a set of instructions combined with a set of inputs, and a unique hash is made from that.
If you make a derivation whose result is the invocation of another, and you try and grab the outcome from that derivation, here’s what will happen: - it will generate the hash - it will look that hash up in your local /nix/store - if not found it will look that hash up in any remote caches you have configured - if not found it will create it using the inputs and instructions
This is transitive so any missing inputs will also be searched for and built if missing, etc.
So if the outcome from your process is something you want to keep and make accessible to other machines, you can do that.
If the machines differ in architecture, the “inputs” might differ between machines (e.g. clang on Mac silicon is not the same as clang on x86-64) and that would result in a different final hash, thus one computation per unique architecture.
This is ultimately the correct behaviour as guaranteeing identical output on different architectures is somewhat unrealistic.
Nix can be used as a build system in the same way that bazel can. It already has all of the tooling - a fundamental representation of a hermetic DAG, caching, access to any tool you need, and a vast selection of libraries.
The only catch is that no one has used it to write a build system for it in public yet. I’ve seen it done in a couple of companies, though, as using Nix to only partially manage builds can be awkward due to caching loss (if your unit of source is the entire source tree, a tiny change is an entirely new source).
Or you can also go to the extreme and do 1:1 source to derivation mapping So for example if ur project has 100 source files it could be built from 100 derivations, the language/CLI tools are flexible enough for that
https://discourse.nixos.org/t/distributed-nix-build-split-la... https://discourse.nixos.org/t/per-file-derivations-with-c/19...
Don't know tho if there any well working smart nix tools which can make it well working /efficient, in theory it's very possible, just unsure about practicality/overheads
[1]: https://chromium.googlesource.com/chromiumos/bazel/+/HEAD/do...
What systems don't just work by this criteria?
Just because something is statically linked vs dynamically linked, as long as you are within "normal expected operating conditions", does it really make a "just works vs doesn't work" quality difference?
> it just works, but...
That still doesn't tell us how low the parent commenter's standards for "just works" are. It's irrelevant.
EDIT: that was meant to be a joke, I forgo HN doesn't support emojies.
This seems a weird thing to complain about =)
Running a handful of containers representing major applications is more reasonable and the memory wastage may be worth it to avoid dependency conflicts.
Containers make a lot of sense to me on servers ("deploy a controlled environment"), but often on Desktop I feel like they are used as a solution to "I don't know how to handle dependencies" or "My dependencies are so unstable that it is impossible to install them system-wide", both of which should be solved by making slightly better software.
In a statically linked system, your dependency manager will update more packages.
And if your program is written in C/C++/Go/Rust, then yes, it will be recompiled.
Oasis seems to have a good way of doing that, with the whole system being built in a single tree by an efficient build tool (my recollection from last time it was posted).
A dynamic executable needs to relink every time it's run, which also takes time.
You say that as if it's such a burden. But it's really not.
I'm somewhat sympathetic to the space argument, but a package manager/docker registry means that updating software is very easy. And it happens all the time for other reasons today anyhow.
On the contrary, I find it relevant: I think that the modern way is wasting way, way too much.
... oh wait, the apps have to hint that it's possible. Nebbermind.
But I wouldnt consider this bloat. To me it is just a better seperation of concerns. To me bloat would be to have a system that has to keep track of all library dependencies instead, both from a packaging perspective but also in runtime. I think it depends where you are coming from. To me static linking is just cleaner. I dont care much for the extra memory it might use.
In the days of fast networks, embedded OSs, emphemeral containers, and big hard drives, a portable static binary is way less complex and only somewhat less secure (unless you're regularly rebuilding your containers/execs in which case it's break even security wise or possibly more secure, simply because each exec may not include vulnerable code)
I've been thinking (not a Linux expert by any means) the ideal solution would be to have better dependency management: I think a solution could be if say binaries themselves carried dependency information. That way you get the benefits of dynamic and static linking by just distributing binaries with embedded library requirements. Also, I think there should be a change of culture in library development to clearly mark compatibility breaks (I think something like semantic versioning works like that?).
That way, your software could support any newer version up to a compatibility break -- which should be extremely rare. And if you must break compatibility there should be an effort to keep old versions available, secure and bug free (or at least the old versions should be flagged as insecure in some widely accessible database).
Moreover, executing old/historical software should become significantly easier if library information was kept in the executable itself (you'd just have to find the old libraries, which could be kept available in repositories).
I think something like that could finally enable portable Linux software? (Flatpak and AppImage notwithstanding)
If Linux dependency management worked well, there would be no need or appetite for docker. But it works badly. So people just use docker and flatpak and whatnot instead, while my hard drive gently weeps. I don’t know about you, but I’m happy to declare bankruptcy on this project. I’d take a 2mb statically linked binary over a 300mb Linux docker image any day of the week.
Then, when there are a couple dozen applications/etc that depend on that library, it's almost an impossible problem because each of those applications then needs to be updated in lockstep with the library version. There is nothing "clean" about how to handle this situation short of having loads of distro maintainers showing up in the upstream packages to fix them to support newer versions of the library. Of course, then all the distro's need to agree on what those versions are going to be...
Hence containers, which don't fix the problem at all. Instead they just move the responsibility away from the distro, which should never really have been packaging applications to begin with.
I disagree here: the whole point of a "software distribution" is to "distribute" software. And it does so by packaging it. There is a ton of benefit in having distro/package maintainers, and we tend to forget it.
I kindly disagree here. Linux dependency management does work well. The problem is the bad libraries that don't do semver properly, and the users who still decide to use bad libraries.
If people stopped using libraries that break ABI compatibility, then the authors of those libraries would have to do it properly, and it would work. The reason it doesn't work is really just malpractice.
You can call it malpractice but it's not going to stop so in practice you need a way to deal with it.
The question then is where we want to put the bar. I feel like it is too low, and most software is too bad. And I don't want to participate in making tooling that helps lowering the bar even more.
So I think it would be more accurate to say that "it doesn't work for lower quality software". And I agree with that.
The bigger dependency management problem is that every distro has their own package manager and package repository and it's tough for one application developer to build and test every kind of package. But if they just ship a binary, then it's up to the poor user to figure out what packages to install. Often the library you need may not even be available on some distros or the version may be too old.
It’s a great way to start contributing to the distribution at large while scratching an itch and providing a service to individual projects.
As the developer of an open source library, I don't think that you should distribute it for systems that you don't use; someone else who uses it should maintain the package. It doesn't have to be a "distro maintainer". Anyone can maintain a single package. I am not on a very mainstream distro, and I still haven't found a single package that I use and is not already maintained by someone in the community (though I wish I did, I would like to maintain a package). My point is that it really works well :-).
I disagree with the idea that we should build a lot of tooling to "lower the bar" such that devs who don't know how to handle a library don't have to learn how to do it. They should learn, it's their job.
For proprietary software, it's admittedly a bit harder (I guess? I don't have much experience there).
They list paths to libraries, but not the exact version that the executable depends on. It is a common occurrence for executables to load versions of libraries they were not designed to be used with.
$> ldd $(command -v ls)
linux-vdso.so.1 (0x00007ffd5b3a0000)
libcap.so.2 => /usr/lib/libcap.so.2 (0x00007f6bd398c000)
libc.so.6 => /usr/lib/libc.so.6 (0x00007f6bd3780000)
/lib64/ld-linux-x86-64.so.2 => /usr/lib64/ld-linux-x86-64.so.2 (0x00007f6bd39e5000)I still think better listing dependencies (perhaps with the option to pin an exact version?) would be helpful, as well as better usage of something like semver. Someone mentioned binaries include paths to dependencies, but as far as I know, there is no tool to automatically try to resolve those dependencies or standard interface, maybe some more tooling in this area would help.
Another nice point about how it current works is that I think it relieves work from programmers. The policy of "Don't worry about distribution (just tell us it exists)" from distros seems like one less headache for the creator (and you can provide static linked binaries too if you want).
As most things in life, the ideal is somewhere in the middle...
If what you're trying to do is run a single program on a server somewhere, then yes absolutely a static binary is the way to go. There are lots of cases, especially end user desktops, where this doesn't really apply though.
In my opinion the debate over static vs dynamic linking is resolved by understanding that they are different tools for different jobs.
Windows is basically all self-contained executables and the few times it isn't it's a complete mess with installing VC++ redistributables or the correct Java runtime or whatever that clueless users inevitably mess up.
We have the disk space, we have the memory, we have the broadband to download it all. Even more so on desktop than on some cheap VPS.
With the caveat that the "standard library" they depend on is multiple GBs and provides more features than entire Gnome.
Also MS always worked in some tech to avoid library duplication such as WinSxS or now MSIX has autodedupe even at the time of download.
If done properly, you can have multiple major versions of something and that's fine. If one app depends on libA.so.1.0.3, the other on libA.so.1.1.4, and they can't both live with 1.1.4, it means that `libA` did something wrong.
One pretty clear solution to me is that the dev of libA should learn good practice.
Heck for a long time upgrading glibc by a minor version was almost guaranteed to break your app and that was often intentional.
Sure :-). I just find it sad that app1 and app2 then use the bad libA. Of course that is more productive, but I believe this is exactly the kind of philosophy that makes the software industry produce worse software every year :(.
But still I like to make it clear that the software industry goes in that direction because of quality issues, and not because the modern ways are superior (on the contrary, quite often) :-).
I can accept that someone needs to make a hack, but I really want them to realize (and acknowledge) that it is a hack.
I recognize that you probably weren't confused on this I'm just clarifying for others since the whole ecosystem can be a bit confusing.
understanding that they are different tools for different jobs
Then one dynamically links the core libraries and statically links everything else. This solves the problem that a bug/exploit found in something like OpenSSL doesn't require the entire system to be recompiled and updated while allowing libraries that are not stable, used by few packages, etc, to be statically linked to their users. Then, when lib_coolnew_pos has a bug, it only requires rebuilding the two apps linked to it, and not necessarily even then if those applications don't expose the bug.
Agreed, and that is already totally possible.
- If you split your project in libraries (there are reasons to do that), then by all means link them statically.
- If you depend on a third party library that is so unstable that nobody maintains a package for it, then the first question should be: do you really want to depend on it? If yes, you have to understand that you are now the maintainer of that library. Link it dynamically or statically, whichever you want, but you are responsible for its updates in any case.
The fashion that goes towards statically linking everything shows, to me, that people generally don't know how to handle dependencies. "It's simpler" to copy-paste the library code in your project, build it as part of it, and call that "statically linking". And then probably never update it, or try to update it and give up after 10min the first time the update fails ("well, the old version works for now, I don't have time for an update").
I am fine with people who know how to do both and choose to statically link. I don't like the arguments coming from those who statically link because they don't know better, but still try to justify themselves.
How? Take for instance OpenSSL mentioned above. I have a software to distribute for multiple Debian versions, starting from Bullseye which uses OpenSSL 1.x and libicu67. Bookworm the more recent has icu72 and OpenSSL 3.x which are binary-incompatible. My requirement is that I do only one build, not one per distro as i do not have the manpower or CI availability for this. What's your recommendation?
Well you build OpenSSL as a static library, and you use that...
> Take for instance OpenSSL mentioned above.
However for something like OpenSSL on a distro like Debian, I really don't get why one would want it: it is most definitely distributed by Debian in the core repo. But yeah, I do link OpenSSL statically for Android and iOS (where anyway the system does not provide it). That's fairly straightforward, I just need to build OpenSSL myself.
> My requirement is that I do only one build
You want to make only one build that works with both OpenSSL 1 and OpenSSL 3? I am not sure I understand... the whole point of the major update is that they are not compatible. I think there is fundamentally no way (and that's by definition) to support two explicitly incompatible versions in the same build...
I mean yes that's what I do but see my comment, I was asking specifically about dynamic linking mentioned by the parent (OpenSSL is definitely a "core library")
> I think there is fundamentally no way (and that's by definition) to support two explicitly incompatible versions in the same build.
Yes, that's my point - in the end static linking is the only thing that will work reliably when you have to ship across an array of distros even for core libraries... The only exceptions in my mind is libgl & other drivers
Really, that's the job of the distro/package maintainers. As a developer, you provide the sources of your project. If people want to use it on their respective distro, they write and maintain a package for it, or ask their distro maintainers to do it. That is the whole point of the distro!
> or ask their distro maintainers to do it.
This only works if you're using a rolling-release distro. You can't get new packages in the repos of Ubuntu 20.04, Suse Leap, Fedora 30 or Debian Bullseye.
This is largely true and how most proprietary software is deployed on Linux.
glibc is pretty good about backwards compatibility. It gets shit for not being forwards compatible (i.e. you can't take a binary linked against glibc 2.34 and run it on a glibc 2.17 system). It's not fully bug for bug compatible. Sometimes they'll patch it, sometimes not. On Windows a lot of applications still link and ship their own libc, for example.
xlib et al don't break in practice. Programs bring their own GUI framework linking them and it'll work. Some are adventurous and link against system gtk2 or gtk3. Even that generally works.
OpenSSL does have a few popular SONAMEs around but they have had particularly nastily broken APIs in the past. Many distros offer two or more versions of OpenSSL for this reason. However, most applications ship their own.
If you only need to talk to some servers, you can link against system libcurl though (ABI compatible for like twenty years). This would IMHO be much better than what most applications do today (shipping their own crypto + protocol stack which invariably ends up with holes). While Microsoft ships curl.exe nowadays, they don't include libcurl with their OS. Otherwise that would be pretty close to a universally compatible protocol client API and ABI and you really wouldn't have any good reason any more to patch the same tired X.509 and HTTP parser vulnerabilities in each and every app.
Even today, dynamic linking is not only a security feature but also serves convenience. A security fix in OpenSSL or libwebp can be applied to everything that uses them by just updating those libraries instead of having to rebuild userland, with Firefox, Emacs, and so on.
I always thought the better security practice is statically linked Go binary in a docker container for namespace isolation.
Golang tooling provides some reasonable mechanisms to keep dependencies up to date. Any given C program might or might not.
So that would not be less secure, but it would also not make it more secure than dynamic linking with a good mechanism, right?
They cite the main benefits being this: "Compared to dynamic linking, this is a simpler mechanism which eliminates problems with upgrading libraries, and results in completely self-contained binaries that can easily be copied to other systems".
Even that "easily be copied to other systems" sort of cites one of the security downsides. Is the system you're copying it to going to make any effort to keep the transient statically linked stuff in it up to date?
Just to add to what you said: in the old days the linker would include only the .o files in the .a library that were referenced. Really common libraries like libc should be made to have only a single function per .o for this reason.
But modern compilers have link time optimization, which changes everything. The compiler will automatically leave out any items not referenced without regard to .o file boundaries. But more importantly, it can perform more optimizations. Perhaps for a given program a libc function is always called with a constant for a certain argument. The compiler could use this fact to simplify the function.
I'm thinking that you might be giving up quite a lot of performance by using shared libraries, unless you are willing to run the compiler during actual loading.
Even without lto, you can have the same results in C++ by having your library in the form of a template- so the library is fully in the /usr/include header file, with nothing in /usr/lib.
It was not exactly like that. Yes, the .o file granularity was there but the unused code from that .o file would also get linked in.
The original UNIX linker had a very simple and unsophisticated design (compared to its contemporaries) and would not attempt to optimise the final product being linked. Consider a scenario where the binary being linked references A from an «abcde.o» file, and the «abcde.o» file has A, B, C, D and E defined in it, so the original «ld» would link the entire «abcde.o» into the final product. Advanced optimisations came along much later on.
It is exactly the same with the dynamic linking due to the demand paging available in all modern UNIX systems: the dynamic library is not loaded into memory in its entirety, it is mapped into the process's virtual address space.
Initially, there is no code from the dynamic library loaded into memory until the process attempts to access the first instruction from the required code at which point a memory fault occurs, and the virtual memory management system loads the required page(s) into the process's memory. A dynamic library can be 10Gb in size and appear as a 10Gb in the process's memory map but only 1 page can be physically present in memory. Moreover, under the heavy memory pressure the kernel can invalidate the memory page(s) (using LRU or a more advanced memory page tracking technique) and the process (especially true for background or idlying processes) will reference zero pages with the code from the dynamic library.
Fundamentally, dynamic linking is the deferred static linking where the linking functions are delegated to the dynamic library loader. Dynamic libraries incur a [relatively] small overhead of slower (compared to statically linked binaries) process startup times due to the dynamic linker having to load the symbol table, the global offset table from the dynamic library and performing the symbol fixup according to the process's own virtual memory layout. It is a one-off step, though. For large, very large and frequently used dynamic libraries, caching can be employed to reduce such overhead.
Dynamic library mapping into the virtual address space != loading the dynamic library into memory, they are two disjoint things. It almost never happens when the entire dynamic library is loaded into memory as the 100% code coverage is exceedingly rare.
Yes, but often a one off step that sets all your calls to call through a pointer, so each call site in a dynamic executable is slower due to an extra indirection.
> For large, very large and frequently used dynamic libraries, caching can be employed to reduce such overhead.
The cache is not unlimited nor laid out obviously in userspace, and if you have a bunch of calls into a library that end up spread all over the mapped virtual memory space, sparse or not, you may evict cache lines more than you otherwise would if the functions were statically linked and sequential in memory.
> as the 100% code coverage is exceedingly rare.
So you suffer more page faults than you otherwise have to in order to load one function in a page and ignore the rest.
That is true, however in tight loops or in hot code paths it is unwise to instigate a jump anyway (even into a subroutine in the close locality). If the overhead of invoking a function in the performance sensitive or critical code is considered high, the code has to be rewritten to do away with it, and it is called microoptimisation. This will also be true in the case of the static linking.
Dynamic libraries do not cater for microoptimisations (which are rare) anyway. They offer greater convenience with a trade-off over the maximum code peformance gains.
> The cache is not unlimited nor laid out obviously in userspace […]
I should have made myself clearer. I was referring to the pre-linked shared library cache, not the CPU cache. The pre-linked shared library cache reduces the process startup time and offer better user experience. The cache has nothing to do with performance.
> So you suffer more page faults than you otherwise have to in order to load one function in a page and ignore the rest.
I will experience significantly fewer page faults if my «strlen» code comes from a single address in a single memory page from 10k processes invoking it (the dynamic library case) as opposed to 10k copies of the same «strlen» sprawled across 10k distinct memory pages at 10k distinct memory addresses (the static linking case).
Not that I really know anything about it, ask jart
Dependency hell comes from bad dependencies that don't do semver properly. Choose your deps carefully, and that's perfectly fine.
> Feels like every single app is a bundled web browser these days anyways.
Yep, that's apparently the best way to use the bad libraries people want to use and not give a damn about semver.
> Software using Semantic Versioning MUST declare a public API. This API could be declared in the code itself or exist strictly in documentation. However it is done, it SHOULD be precise and comprehensive.
If it's not in the API, it is not bound by the rules. Many ecosystems come up with various norms, like Rust has, to help guide people in this. But it's almost certainly not a semver violation to make the change described in the XKCD because "handle unknown unknowns" is not possible. That doesn't mean that we should throw out the entire idea of software assisted upgrades to dependencies.
That's the thing: I feel like people tend to call "dependency hell" what I would consider downright malpractice. "Shared libraries don't work because they require good practice" is, IMO, not a good argument against shared libraries. If you need to design your tool with the constraints that "users will use it wrongly", then it's already lost.
The breaks happen regardless, but you have a principled way of defining whose fault/problem it is.
1. Software depending on versions of libraries that are newer than the latest version available on the distro you have to use (cough RHEL 8). E.g. this very day I ran into a bug where some Asciidoctor plugin craps out with an error because my version of Ruby isn't new enough. Ruby's advice for how to install Ruby is "use your package manager; you will get an old version btw fuck you".
90% of the time it's bloody glibc. Every Linux user has run into the dreaded glibc version error dozens of times in their career.
2. Software that can't install multiple versions of the same package, leading to diamond dependency issues. Python is very bad for this.
That is a fair point, but it raises a question: if you absolutely need to use software that is not packaged by your distro of choice and that you cannot package yourself (are you sure you can't maintain a "community" package yourself with RHEL?), maybe you don't want that distro.
Different distros come with different goals. If you take a "super slow but secure" distro, it will be slow and secure. If you take a rolling distro, you get updates very quickly but it has drawbacks. It depends on the use-case, but going for a "slow and secure" distro and then building tooling to work around that choice ("nevermind, I'll ship new and less mature software anyway, statically linked") seems to defeat the purpose of the distro... right?
Well I definitely don't want RHEL 8 but unfortunately I have to use it because some software I use requires it (RHEL 9 doesn't have old enough versions of some libraries) or is only certified on it (this is for work).
But even if I was using a more modern distro, none of them have all software packaged. And no I obviously don't want want to become a packager. Some of the software I use is closed source so that's not even an option.
The only real option is Docker (or Apptainer/Distrobox etc), which sucks.
The fundamental model of "we'll just ship all software that exists; all software is open source" that most distros try to use is just fundamentally wrong.
Snap and Flatpak are trying to fix that but in my experience they aren't remotely ready yet.
That's where I disagree. It's not that hard, and if more people did it, more software would be packaged. Actually I am yet to find a library that I actually need and that is not already packaged and maintained by someone from the community. Then I could finally maintain one myself.
To me, you're basically saying: "I don't want to learn and commit to maintain a package for my distro, because reason, but I am fine spending time with all that tooling that I say "sucks" (Docker/Apptainer/Distrobox)". That's what I don't really get. There is a solution that works well (for me, at least): package the software that is not already available yourself.
> Some of the software I use is closed source so that's not even an option.
I would not want to maintain a package with proprietary binaries that I don't own, that's for sure. But if you need to, you can. As long as the author distributes binaries for your platform, it's not much harder than making an open source package.
Well we'll have to agree to disagree on that, but I think if you told most people that the normal way to install third party software for Linux was to become a package maintainer they would rightly laugh you straight to the asylum.
> That's what I don't really get.
The reason is that Docker, Apptainer etc are much easier than creating packages for all the dependencies of the software I want to run. Multiplied by the number of distros I need to use. Pretty obvious no?
Take it like this: in the current state, I am struggling to find a single interesting library for which I could become a package maintainer for my non-mainstream Linux distro, because there always exists one. Maybe not in the core repo, maybe only in the community repo. But still: I don't maintain a single package today, because I haven't found one that I use and that it not already maintained by somebody else.
Really, if you decide to create packages for all the dependencies of the software you want to run, congratulations: you have just created a new distro from scratch. But even most new distros don't do that :-).
In other words, there are way more developers than libraries that are worth being depended on. So even if we wanted to, not everybody can maintain a single package. There are just not enough packages out there for that, by very, very far.
I would leap for joy to see Red Hat or Debian or even Gentoo make inroads here, but I haven’t looked closely enough and recently at Debian, and .ebuild files hurt my brain. I do believe I recall Gentoo requiring more work to get my packages available and listed anywhere.
It's usually straightforward with end user applications, such as bash or git or ruby. Things more likely to be tied to the rest of the operating system, such as SELinux or PAM, are less likely to work. If there are dependencies to things that is release dependent, it's not worth the bother.
Maybe you can argue you don't want to "become a packager", but someone has already done the work for you and you don't need more than superficial knowledge about the system to do it. In most distributions, source packages aren't harder to install than binary packages.
Most things might be solved by everyone doing SemVer. And for all I know some communities might be running like greased pigs in a chute exactly because they use SemVer (I don’t tend to hear about the everyday everything-is-working stories on HN). But also doing static linking a bit more seems like it would help a lot with the same problem.
[1] All based on discussions I’ve seen. Not really personal experience.
[2] Again, making a spec/manifesto which is both about machine-readability and about shaming people for vague things is very muddled. Although I don’t know how much the latter is about the culture around it rather than the spec itself.
> It seems impossible to solve this by just everyone adopting a manifesto that one GitHub guy wrote many years ago
Well by "semver" I mostly mean "change the major number to indicate a change of ABI", I don't mind so much about the other numbers in this case. But that's a good question: I don't know when it started being a thing. I would guess much, much earlier than GitHub, though.
> human judgement about what is breaking and not
Hmmm... ABI compatibility for the public interface is not really subjective, or is it?
> weird implicit social taboos about doing major releases “too often”
Yes I don't get that one and I fight hard against it.
> But also doing static linking a bit more seems like it would help a lot with the same problem.
Well I am not fundamentally against static linking; to me it makes sense to do a mix, with the caveat that if you link something statically, then you are the maintainer of that code. Whereas if you link a system library dynamically, you merely depend on it.
My problem is about moving to "static linking only" (or "by default", but I don't even know if Rust allows dynamic linking at all?).
Might as well go all in and use something with pervasive virtualization like Qubes.
Also the biggest problem I had with QubesOS is that it doesn't support GPU (for security reasons). It feels like that was a big cause for the reduced performance. I wish there was a solution for the GPU, and then I would love to daily-drive QubesOS.
https://neowutran.ovh/qubes/articles/gaming_windows_hvm.html
https://forum.qubes-os.org/t/nvidia-gpu-passthrough-into-lin...
https://forum.qubes-os.org/t/seamless-gpu-passthrough-on-qub...
Yes, the passthrough is probably a huge avenue for attacks. Possibly VirtualGL too, I know less about that.
https://neowutran.ovh/qubes/articles/gaming_windows_hvm.html
I believe the NVIDIA drivers after version 465 may not have this issue.
Here’s a report of this working on Qubes/Xen: https://forum.qubes-os.org/t/qubes-gpu-passthrough/661/12
However you may need to hide the virtualization from some games or other software, where Qemu/KVM can be more flexible.
There’s a project and some discussion to use these with Qubes, but it’s early days: https://github.com/nrgaway/qubes-kvm-dev
https://forum.qubes-os.org/t/porting-qubes-to-hypervisors-ot...
> However you may need to hide the virtualization from some games or other software, where Qemu/KVM can be more flexible.
How prevalent is this? Is it basically just multiplayer games employing anticheat?
The fact that people distribute their app with a full rootfs in a Docker containers says more about the fact that they don't know how to link stuff properly, IMHO.
And yes, you totally can do it. Most Linux software just doesn't bother because - while you can do it, in a lot of languages (C, Python, etc.) it's quite a pain to do. Especially if you have lots of dependencies.
It's much easier to bundle dependencies in languages that statically link by default (Go, Rust) because of course statically linking implicitly bundles them.
> It's much easier to bundle dependencies in languages that statically link by default
> It's not about static vs dynamic linking at all.
Sorry I'm confused :/. What did I say that you disagree with?
You wouldn't want have 100 tools statically link the entirety of chromium, but for normal C library sizes you don't get bloat. The preference for dynamic libraries in Linux distros is just so they can roll out patch updates in one place instead of rebuilding dependents.
Also I think inlining would typically increase the total size of output rather than decrease it.
You can see this by running "pmap <pid> -XX" (the output is very wide- probably load it into an editor). Look at the shared vs. private pages.
Also: There is another way to automatically share pages between different programs: de-duplication. This would require common libraries to be statically linked on page boundaries. The OS would quickly de-duplicate during loading by hashing the pages. VMs use this technique to increase effective memory when there are many guest OS running.
Inlining external code reduces the size not only by saving the call, PLT and and stack dance, but also through specialization (removal of unused conditional, pruning of no longer referenced symbols) as the code is locally optimized. This further reduction in size further improves cache behavior and performance.
Duplication can be an issue (not necessarily for performance, but for total binary size), but compilers have heuristics for that. Even just having the symbol local saves some space and call overhead though (no PLT).
The case for the shared library having better caching implies multiple processes that are distinct executables (otherwise they share program memory regardless of linkage) trying to hammer it at once, sharing the continued caching, but such scenario is hurt by the call overhead and lower optimization opportunities, negating the result.
But this is the most common case for desktops/multipurpose systems.
On my desktop there are tens or hundreds distinct processes sharing most of their code.
Depending on your CPU, you might have, say, 32KB of 8-way associative instruction cache per core. Just being shared does not make it fit in the cache.
A shared library would only be there across processes of different executable images if its users primarily, continuously execute the same paths in shared libs rather than anything unique in their own executable image - e.g., they'd more or less need to be stuck in the same processing-intensive shared routine in the lib. There would also have to be no other processing done in between by other processes that would have trashed the cache.
On the other hand, the severe cache penalty of longer code paths for each executable and the larger PLT call overhead will universally lead to a loss in performance for all library usage.
The scenarios you may hit where different processes are actually executing the same shared code paths to the point of benefiting from shared cache utilization would be cases where they share executable image as well. E.g., browser processes, threads, compilers. Electron too if using system-packaged electron binaries.
Yes, like libc/WinApi, Cairo/whatever graphics library of your OS, Gtk/Qt etc
All of the apps on my desktop (I don't use electron) share vast majority of their code (see above) and spend most of their time drawing UI through shared libs or doing their own business logic but that's part of their code and not subject to shared lib overhead.
No, you don't have a desktop environment where a majority of your unique executables all spend time at the same time in the same small, compute-heavy libc routine with no other processes to trash the cache in between.
For Gtk for example, the applications are not taking the same inputs and drawing the same GUI at the same time, with no other processes in between to wipe the cache.
Instead they're primarily running their own application logic in their own time, and interaction with Gtk (accepting input, rendering) is on timescales so long that the cache has been wiped out over and over in between (16ms is practically infinity at these scales). In these cases, the cache will be filled at the time of execution with e.g. that apps runtime data, widget tree and what not.
At the same time, remember that a static routine is much smaller and faster. Even if way say you fetch a shared library routine from cache and save some cycles there, every single call to it incurs large performance hits over the static linkage: a few cycles to every call from the PLT, possibly many cycles from poorer optimization (e.g., branches you never need), and cycles from not fitting as well in the tiny instruction cache as the process executes it.
... And if that shared lib routine calls other shared libs, then you get to apply the overheads and lost optimization recursively. This recursion where the static linkage pruning is especially effective: you might have tens or hundreds of megabytes of dependencies dynamically, but single megabyte static output as unused functionality is pruned.
There is no realistic scenario where dynamic linkage wins on performance or cacheability - it just doesn't play well with how caches end up used. Overall system memory utilization can be slightly lower for dynamic linkage in some cases, but not in a notable way.
I have 16GB of RAM and usually when working all of it is in use. If everything was compiled statically I would get massive swapping.
No, it does not, it worsens it.
For example, «strlen», if it comes from a dynamic library, will be loaded into the physical memory once and only once, and it will be mapped into each process's address space as many times as there are processes. Since «strlen» is a very frequently used function, there is a very high chance that the page will remain resident in memory for a very long time, and since the physical page is resident in memory, there is also a very good chance that the page will remain resident at least in the L2 cache, but – depending on circumstances – in the L1 cache, too. A TLB flush might not even be necessary in specific circumstances, which is a big performance win. It is a 1:N scenario.
With the static linking, on the other hand, if there are 10k processes in the system, there will be 10k distinct pages containing «strlen» loaded into memory at 10k random addresses. It is a M:N scenario. Since the physical memory pages are now distinct, the context switching will nearly always require the TLB to be flushed out which is costly or very costly, and more frequent L1/L2 cache invalidations due to «strlen» now residing at 10k distinct physical memory addresses.
P.S. I am aware that C compilers now inline «strlen» so there is no actual function call, but let's pretend that it is not inlined for the sake of the conversation.
If your libc was statically linked, you would not need the built-in - the strlen impl from your libc would get inlined by LTO.
The chances of a particular routine being in L1 is absolutely miniscule - it's hard enough to keep a single process and it's data in L1 and L2. What might happen is that you find it in L3, but: 1. The code you're loading is now much larger (fitting less well in L1 so you'll get more L1 misses) and slower (cache aside, it has redirection overhead and has not been LTO'd for this use), and 2. The inlined version would probably also be found in L3 - either resident or prefetched as that section if the process executable obviously had to be loaded to switch to it. 3. Unless the system is idle, the cache will be trashed in between process switches by the loads from other processes.
So while you could technically have a case where the shared lib is in cache, I do not think a realistic scenario exists where that setup wins out. There are more distinct pages, but the pages didn't fit in the first place: by having each process access fewer pages overall it can miss less while it is running.
The argument is entirely contrived and has no root in facts. Compiler built-ins appeared in GNU C/C++ compilers as an attempt to replace the non-portable inline assembly with portable primitives – across compilers and across different architectures as well. The rationale is well documented in the GNU C/C++ compiler v2.3 circa documentation, and it has nothing to do with the dynamic linking.
The use of the compiler built-ins increased once the C/C++ compilers gained the interprocedural, in-file, holistic optimisation capabilities – to improve the quality of the generated code. Moreover, compiler built-ins had been present in some form even in the 32-bit Watcom C compiler for MS-DOS and MS-DOS had no shared libraries or whatsoever.
> The chances of a particular routine being in L1 is absolutely miniscule - it's hard enough to keep a single process and it's data in L1 and L2 […]
CPU caches work at addresses being accessed level, not at the process level. The CPU knows nothing about processes – the CPU is a code interpreter.
One copy of «strlen» in a single memory page at a single physical memory address shared across all processes has a much better chance of staying in the cache for a longer time as opposed to 10k copies of the same «strlen» implementation in 10k memory pages strewn across 10k distinct physical addresses. A single page that is accessed frequently has a higher hit rate and, thus, fewer chance of getting evicted from the cache – these are the basics one can't go against. CPU's other than Intel CPU's have larger or large I-caches, too, therefore very frequently used code has higher chances of survival in the CPU cache. Most importantly, however, the CPU cache (L1/L2) size is not the bottleneck, the TLB size is – a frequently accessed address is better from the TLB perspective than 10k distinct addresses as it will result in a fewer number of the TLB flushes.
Lastly, the shared library cache I was referring to has nothing to do with the CPU execution time. It is the cache where the shared libraries are «pre-linked» to reduce the startup, the GOT fixup and the dynamic library initialisation times – to improve the user experience, not performance.
This is missing the point entirely.
GCC needs to emit e.g. memory copies. Before, this was inline assembly replicated over and over. Now, it's a call to __builtin_memcpy.
The point missed is that GCC always considered the idea of calling memcpy entirely unacceptable as the performance would be horrible over an inline implementation.
The proof of this intent lies in later optimizations: Not only would GCC never want to emit such slow calls, it replaces your explicit libc calls with builtins because obviously you wouldn't want to do something as slow as a dynamic linkeage call.
With static linking and LTO, the libc implementation becomes as good as the builtin, rendering the latter pointless. GCC just cannot assume this to be the case.
> CPU caches work at addresses being accessed level, not at the process level.
No, CPU caches do not work on addresses, they work on tags to be pedantic. Either way, I never said that caches are process level. I said that they do not survive across multiple processes - not because of flushing, but because of trashing. I.e., if you have three processes, A, B and C, where A and C run shared code while B something else, and you switch A -> kernel -> B -> kernel -> C, then by the time you made it form A to C your cache is has been trashed by both B and the kernel.
Now, instead of 3 processes and one routine, make it thousands of threads and gigabytes of shared libraries.
> One copy of «strlen» in a single memory page at a single physical memory address shared across all processes
Again, strlen is a terrible example: 10k copies of strlen being a handful of bytes in the current instruction stream, prefetched and branch predicted will outperform that shared page to an outright ridiculous extent and might even be smaller in total: a 10k copies of a handful of bytes vs. 10k calls and PLT indirections + the un-inlined function. Because it is literally less memory, it also trashes the TLB less.
Even in more realistic cases, remember the TLB hit of the PLT table in each application, not to mention the many more pages consumed by the bulkier implementation. In fact, let's focus a bit on the TLB. The most basic Gtk app links at least 80 libraries worth over 90 megabytes on my system. An L1 TLB has about 64 entries, the L2 around a thousand or so - so it can reference ~16MB worth of memory or thereabout. In other words, even the L2 TLb is about 6 times too small to keep the libraries of the simplest possible gtk app cached.
Heck, take just libicudata at 30MB. Of course, I wouldn't suggest statically linking that, but just pointing out that a single dependency of a Gtk app is enough to fill up the TLB twice, nullifying the idea of any cache benefit to using these libraries.
"Yes but at least they can have libicudata in L3!" - yeah, no - not only would it compete with other dynamic dependencies (for this and other processes), but more importantly the applications also need to process data. A single Gtk app on a 4k monitor will, for example, be managing at least two 32MB framebuffers (3840x2160x4, x2 for double buffering), so that's most of your cache gone during draw before you even consider the input to the draw or any actual functionality of the app!
The best-case for dynamic linkage performance is cases where call cost is irrelevant, e.g. when calling compute routines. There is no point whatsoever in considering CPU caches outside the scope of the currently running process.
> KSM only merges anonymous (private) pages, never pagecache (file) pages.
So it wouldn't be able to help with static libraries loaded from different executables. (At any rate, they'd have to be at the same alignment within the page, which is unlikely without some special linker configuration.)
Though it is not a goal of mine to save storage space by using static binaries, and I actually expect to lose space as a tradeoff, I have actually saved storage space in some cases by using static binaries. This comes from being able to remove libraries from /usr/lib. TBH, I am not exactly sure why this is the case. Perhaps in part because one might be storing large libraries containing significant numbers of functions that one's programs never use.
For me using static binaries works well. Even "common" libraries can be removed in some cases by using a multi-call/crunched binary like busybox. This might not work for everyone. I think much depends on what selection of programs the computer owner prefers. (Namely, the dependencies required by those programs.)
With sound, alsa, it is fine since there is IPC/shared-memory based mixing that whatever the playback/capture devices [dmix/dsnoop]. Static linking is reasonable. (pulseaudio[012] IPC interfaces are bloaty kludges, hardly stable in time, 0..1..2.., not to be trusted compared to the hardcore stability of alsa one able to do a beyond good enough job *and* _real_ in-process low latency hardware access at the same time).
x11 and wayland are IPC based, then no issue here neither.
But for the GPU, we would need a wayland vulkan3D-inspired set of IPC/shared-memory interfaces (with a 3D enabled wayland compositor). For compute, the interfaces would be de-coupled from the wayland compositor (shared dma-buffers).
The good part of this would be to free our system interfaces from the ultra complex ELF (one could choose an excrutiatingly simple executable file format, aka a modern executable file format, but will need compilers/linkers support to help legacy support).
There is a middle ground though: everything statically linked, except the apps requiring the GPU driver (for that ELF is grotesquely overkill), still provided as a shared library.
About the shared libs, well, they are the utility shared libs, and the system interface shared libs. With a mostly statically linked elf/linux distro, all the utility libs would be statically linked, and the system interface shared libs would be statically linked if they have an IPC/shared-mem interface. In the end, only the GPU driver is an issue, namely would stay a shared libs.
What is the advantage of using the croc C compiler instead of e.g. TCC?
I wasn't aware of Netsurf (https://www.netsurf-browser.org/); this is really amazing. But it seems to use Duktape as the JS engine, so performance might be an issue.
I'd like an arm 32bit port, which might be a bit easier with this ppc port as an example of 32bit qbe. It'd be nice to try run some hare programs on a gameboy advance :)
Working link: https://www.netsurf-browser.org
Every single link on that page is dead.
https://www.netsurf-browser.org/about/screenshots/
Judging by the screenshots, it can render BBC, its own website, and Wikipedia. Well, it might be able to render others, we just can't tell from the shots. But we can tell those three websites work with all sorts of different window decorations.
Unfortunately, as it seems. On the start page they say "Last updated 2 January 2007". But version 3.11 was released on 28 Dec 2023.
I'm curious how it compares to, say, Alpine with a similar set of packages.
oasis's predecessor would be https://dl.suckless.org/htmlout/sta.li
Many, many props to Michael Forney.
Is there performance differences between the two?
I have been seeing musl used more and more in both Rust and Zig ecosystems lately.
you get weird bugs and failures that don't happen with glibc (like the incomplete dns resolving routines that would fail under some conditions) but you can brag about saving 30-40 mb of disk space.
this project seems to be compromising on quality overall, in the name of having smaller size.
Even BearSSL, by their own website is beta-quality: "Current version is 0.6. It is now considered beta-quality software" (from https://bearssl.org/).
I maintain a large codebase, widely deployed, cross compiled to many cpu architecures that's built atop musl. You're right that historically in the context of people blindly using alpine for their container base that sort of thing might be the case. The newest version of musl solves the thing you're describing and in general most of the complaints about malloc perf or otherwise have been addressed. Avoiding musl to me seems like an outdated trope, but there was a time wherein that take was valid indeed.
Would you accept that kind of reasoning for software running on your pacemaker, or on your insuline pump?
I think we should respect the developers here: they're not claiming production quality level (they're claiming beta-quality level) so it's not correct to use that library in any kind of product and claim any kind of production-level quality.
God helps me I wouldn't implant anything so fundamental in my body with hard dependencies on encrypted communication to a remote agent elsewhere, no matter the advantage.
https://github.com/kubernetes/kubernetes/blob/master/go.mod for one obvious example.
They eventually did fix this, as of musl 1.2.4.
There's some common FUD about rpath being insecure, but that only applies if the binary is setuid (or otherwise privileged) and the rpath is writable by someone other than the binary's owner (all relative rpaths are writable since you can use symlinks; absolute rpaths are writable if they point to /tmp/ or a similar directory, which used to be common on buildbots).
This is really not hard; working around all static linking's quirks is harder.
Global constructors no longer reliably fire unless you are extremely careful with your build system, nor do they run in a predictable order (e.g. you can call a library before it is actually initialized, unlike dynamic linking where only preinit - which nobody uses - is weird), nor can you defer them until dlopen time if you want (which is, admittedly, overdone).
It's possible to link to parts of multiple versions of a library (remember, you have to recurse into your dependencies), as opposed to dynamic libraries where at least you're guaranteed all-or-nothing (which is much easier to detect).
Linking is slower since it always has to be redone from scratch.
Not resilent against system changes. For example, old versions of `bash-static` (grab them from e.g. Debian snapshot and extract them manually; don't install them) are no longer runnable on modern systems since certain system files have changed formats, whereas the dynamically-linked `bash` packages still run just fine.
It also encourages bad stability habits, leading to the equivalent of NPM hell, which is far worse than DLL hell ever was.
You can't use LD_PRELOAD or other dynamic interception tools.
There are probably more reasons to avoid static linking, but I'm trying to ignore the handful from the popular lists.
I’m not sure it’s a great idea for an OS as in the OP, but I do like that they claim accurate incremental rebuilds, to ensure everything get updated. Certainly an interesting experiment!
Edit: just to clarify, I meant "app" as in "something that isn't part of the OS/distribution".
from my understanding glibc is not "religiously" against it, they're against it for technical reasons. In the sense, this is not a dogma. It's about internal details of their implementations.
See: https://stackoverflow.com/questions/57476533/why-is-statical...
"If it's a bug people rely on it's not a bug, it's a feature" Let me guess, he was thinking of the memcpy issue that broke flash. Or maybe something else. And I agree, nobody cares
The spec says that because it was the 70s and nobody had thought better of that or how things would work 30 yrs on, and going with it does not make sense.
And I feel the pain of this hardheadedness when any library deprecates an API when they didn't need. "Oh but it's cleaner now" Again, nobody cares
https://opensource.stackexchange.com/questions/13588/how-sho...
[0]: https://neosmart.net/blog/a-high-performance-cross-platform-...
Edit:
Sorry, the correct link is this one: https://neosmart.net/blog/using-simd-acceleration-in-rust-to...
(Not that the codebase makes much string function usage.)
Looks like a "bug" or better put needed enhancement to LLVM.
And it has so many weird quirks that you need to work around.
***
Static linking makes linking more painful, especially regarding global constructors (which are often needed for correctness or performance). This is not a musl-specific issue, but a lot of people are interested in both.
Just do your builds on the oldest supported system, and dynamic linking works just fine. You can relative-rpath your non-libc dependencies if they would be a pain to install, though think twice about libstdc++.
***
The major advantage of MUSL is that if you're writing a new OS, it's much easier to port.
> And it has so many weird quirks that you need to work around.
I was under the impression that musl stuck closely to the standard, and glibc frequently did its own thing, so 1. it's not musl that's quirky, 2. if you need to detect something, just detect glibc.
There are places where MUSL implements a broad set of GLIBC extensions in order to actually be useful. However, it does not indicate that in any way, and sometimes violates the conditions that GLIBC documents. This requires workarounds.
There are places where MUSL implements a standard interface in a particular way. If you're lucky, this "just" means giving up on performance if you don't know you're using MUSL.
Sometimes MUSL implements its own ABI-incompatible extensions. The time64 transition, for example, is a huge mess regardless, but musl provides no blessed way to figure out what's going on. The only reason it's not an even bigger disaster is that almost nobody uses musl.
https://wiki.musl-libc.org/functional-differences-from-glibc...
Hopefully that's helpful context. Overall since I did linux from scratch half a lifetime ago I've always wondered why something like Oasis hasn't gotten more traction. It's got some ambitious ideas in the README so maybe others have other nice use-cases atop all that. I just see small, statically linked and think 'oh boy if i never have to build my own tools again for some weird board'. If so, I'm here for it.
This is a cool approach on Docker as well.
FROM some:thing AS bins
FROM debian:latest
COPY --from=bins /bin/foo /bin/And then when Nix† is not an option at runtime, dockerTools†† can build a Docker image to do the minimisation+isolation.
That said, Nix might also be completely overkill in some scenarios where static linking would be just fine and very practical. The practical simplicity of a single binary should not be overlooked.
† nixpkgs is sufficient, a full nixos is not needed
†† https://nixos.org/manual/nixpkgs/stable/#sec-pkgs-dockerTool...
Is oasis the "drop in binary" you would use? Or do you use oasis to build the tool that you would use?
"The allure of something like this is I could potentially grab a drop in binary"
From where?
P.S. - oh! and I had friends that loved HP/UX - another one I never got to try
At this point, it would be more useful if someone explained a couple of use cases for dynamic linking.
Which in the days of running Kubernetes clusters on laptops maybe isn't a big deal.
https://github.com/bpowers/musl/blob/master/src/ldso/dlopen....
I tried to hack in a copy of the musl's dynamic loader (and also from old uclibc). But it took a few hours and my only result was segfaults.
Do you have any pointers on making this work?
To debug your problem, do you have a minimal example at your fingertips to try? Just a "hello world" dynlib that is called from a static program that doesn't do anything else.
It's unclear to me what "100%" refers to here, but surely it does not include the Linux kernel or drivers? (I've recently read conversations about how difficult this would be.)
https://news.ycombinator.com/item?id=38852616
TLDR: Linux kernel doesn't have a stable binary kernel interface. And they don't want one.
Given this, the definition of "reproducible build" needs, well, a refined definition, if it includes the Linux kernel.
[1] https://www.kernel.org/doc/Documentation/process/stable-api-...
There is some documentation at least... and I know several Linux distributions have been working on reproducible builds for a long time now - I'd be surprised if there hasn't been good progress on this.
https://www.kernel.org/doc/html/latest/kbuild/reproducible-b...
Not sure if that's what they mean here.
The Linux kernel's lack of a stable ABI (specifically [2]; many userspace APIs are stabilised) doesn't mean individual revisions can't be built reproducibly.
[1]: https://reproducible.archlinux.org
[2]: https://en.wikipedia.org/wiki/Linux_kernel#In-kernel_ABI
https://news.ycombinator.com/item?id=39143029
I also thought sta.li when I saw this was about a statically linked linux system...
I could imagine there were unexpected efficiencies. Although dynamic libraries should be able to share an address space, I think with static libraries, the linked might strip out unused routines.
also, it might be faster
Wouldn't it be better to pile on OpenWRT?
>"oasis uses smaller and simpler implementations of libraries and tools whenever possible:
musl instead of glibc (https://www.musl-libc.org/)
sbase instead of coreutils (https://git.suckless.org/sbase/file/README.html)
ubase instead of util-linux (https://git.suckless.org/ubase/file/README.html)
pigz instead of gzip (https://zlib.net/pigz/)
mandoc instead of man-db (https://mandoc.bsd.lv/)
bearssl instead of openssl (https://bearssl.org/)
oksh instead of bash (https://github.com/ibara/oksh)
sdhcp instead of dhclient or dhcpcd (https://core.suckless.org/sdhcp/)
vis instead of vim or emacs (https://github.com/martanne/vis)
byacc instead of bison (https://invisible-island.net/byacc/)
perp and sinit instead of sysvinit or system 44 (http://b0llix.net/perp/ https://github.com/wereHamster/perp https://troubleshooters.com/linux/diy/suckless_init_on_plop....)
netsurf instead of chromium or firefox (https://www.netsurf-browser.org/)
samurai instead of ninja (https://github.com/michaelforney/samurai)
velox instead of Xorg (https://github.com/michaelforney/velox)
netbsd-curses instead of ncurses (https://github.com/sabotage-linux/netbsd-curses)"
(Oh, and not to quote Dwayne "The Rock" Johnson's character "Maui" from Disney's Moana or anything -- but "You're welcome!" <g> :-) <g>)