As discussed in the maintainer meeting on 2024-01-29.
Mainly this is to avoid a situation where the name is parsed and
treated as a file name, mostly to protect users.
.-* and ..-* are also considered invalid because they might strip
on that separator to remove versions. Doesn't really work, but that's
what we decided, and I won't argue with it, because .-* probably
doesn't seem to have a real world application anyway.
We do still permit a 1-character name that's just "-", which still
poses a similar risk in such a situation. We can't start disallowing
trailing -, because a non-zero number of users will need it and we've
seen how annoying and painful such a change is.
What matters most is preventing a situation where . or .. can be
injected, and to just get this done.
To quote the method doc:
Non-impure derivations can still behave impurely, to the degree permitted
by the sandbox. Hence why this method isn't `isPure`: impure derivations
are not the negation of pure derivations. Purity can not be ascertained
except by rather heavy tools.
This is more conceptually correct (the order does not matter), and also
matches what Hydra already does.
(Nix and Hydra matching is needed for dedup
https://github.com/NixOS/hydra/issues/1164)
More invariants are enforced in the type, and less state needs to be
stored in the main sink itself. The method here is roughly that known as
"session types".
Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
This avoids split-on-whitespace errors:
- No more `bash -c` needed
- No more `shellEscape` needed
- `remote-program` ssh store setting also cleanly supports args (e.g.
`nix daemon`)
- `ssh` uses `--` to separate args for SSH from args for the command to
run.
and will help with Hydra dedup.
Some code taken from #6628.
Co-Authored-By: Alexander Bantyev <balsoft@balsoft.ru>
Factor out `ServeProto::BasicClientConnection` for Hydra to share
- `queryValidPaths`: Hydra uses the lock argument differently than Nix,
so we un-hard-code it.
- `buildDerivationRequest`: Just the request half, as Hydra does some
things between requesting and responding.
Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
Good to document these formats separately from commands that happen to
use them.
Eventually I would like this and `builtins.derivation` to refer to a
store section on derivations that is authoritative, but that doesn't yet
exist, and will take some time to make. So I think we're just best off
merging this now as is.
Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>
Return a value instead of throwing.
Rather than the more trivial refactor of wrapping the return value in
another std::optional, we retain the meaning of the outer optional:
"we know at least something."
So we have changed:
return nullopt -> return nullopt
throw InvalidPath -> return make_optional(nullptr)
return vpi -> return make_optional(vpi)
In rare cases (e.g. when using allowSubstitutes = false), it's
possible that we simultaneously have a DerivationGoal *and* a
SubstitutionGoal building the same path. So if a DerivationGoal
already built the path while the SubstitutionGoal was waiting for a
download slot, it saves us a superfluous download to exit early.
In the "discard" case (i.e. when the store path already exists
locally), when we call parseDump() from a Finally and it throws an
exception (e.g. if the download of the NAR fails), Nix crashes:
terminate called after throwing an instance of 'nix::SubstituteGone'
what(): error: file 'nar/06br3254rx4gz4cvjzxlv028jrx80zg5i4jr62vjmn416dqihgr7.nar.xz' does not exist in binary cache 'http://localhost'
Aborted (core dumped)
Instead of having it be the default method in `Store` itself, have it be
the implementation in `DummyStore` and `LegacySSHStore`. Then just the
implementations which fail to provide the method pay the "penalty" of
dealing with the icky `unimplemented` function for non-compliance.
Picks up where #8217. Getting close to no `unsupported` in the `Store`
interface itself!
More progress on issue #5729.
This is useful for determining quickly which substituters to query.
An alternative would be for users to invoke the narinfo cache db directly,
so why do we need this change?
- It is easier to use. I believe Nix itself should also use it.
- This way, the narinfo cache db remains an implementation detail.
- Callers get to use the in-memory cache as well.
The data was (accidentally?) copied into a std::string,
even though the string is immediately converted into a std::string_view.
The code has been changed to construct a std::string_view directly,
such that one copy less happens.
Most of this is a `catch SysError` -> `catch SystemError` sed. This
is a rather pure-churn change I would like to get out of the way. **The
intersting part is `src/libutil/error.hh`.**
On Unix, we will only throw the `SysError` concrete class, which has
the same constructors that `SystemError` used to have.
On Windows, we will throw `WinError` *and* `SysError`. `WinError`
(which will be created in a later PR), will use a `DWORD` instead of
`int` error value, and `GetLastError()`, which is the Windows equivalent
of the `errno` machinery. Windows will *also* use `SysError` because
Window's "libc" (MSVCRT) implements the POSIX interface, and we use it
too.
As the docs describe, while we *throw* one of the 3 choices above (2
concrete classes or the alias), we should always *catch* `SystemError`.
This ensures no matter how the implementation changes for Windows (e.g.
between `SysError` and `WinError`) the catching logic stays the same
and stays correct.
Co-Authored-By volth <volth@volth.com>
Co-Authored-By Eugene Butler <eugene@eugene4.com>
Also move `SourcePath` into `libutil`.
These changes allow `error.hh` and `error.cc` to access source path and
position information, which we can use to produce better error messages
(for example, we could consider omitting filenames when two or more
consecutive stack frames originate from the same file).
This sets up infrastructure in libutil to allow for signing other than
by a secret key in memory. #9076 uses this to implement remote signing.
(Split from that PR to allow reviewing in smaller chunks.)
Co-Authored-By: Raito Bezarius <masterancpp@gmail.com>
many paths need not be heap-allocated, and derivation env name/valye
pairs can be moved into the map.
before:
Benchmark 1: nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
Time (mean ± σ): 6.883 s ± 0.016 s [User: 5.250 s, System: 1.424 s]
Range (min … max): 6.860 s … 6.905 s 10 runs
after:
Benchmark 1: nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
Time (mean ± σ): 6.868 s ± 0.027 s [User: 5.194 s, System: 1.466 s]
Range (min … max): 6.828 s … 6.913 s 10 runs
the table is very small compared to cache sizes and a single indexed
load is faster than three comparisons.
before:
Benchmark 1: nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
Time (mean ± σ): 6.907 s ± 0.012 s [User: 5.272 s, System: 1.429 s]
Range (min … max): 6.893 s … 6.926 s 10 runs
after:
Benchmark 1: nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
Time (mean ± σ): 6.883 s ± 0.016 s [User: 5.250 s, System: 1.424 s]
Range (min … max): 6.860 s … 6.905 s 10 runs
a bunch of derivation strings contain no escape sequences. we can
optimize for this fact by first scanning for the end of a derivation
string and simply returning the contents unmodified if no escape
sequences were found. to make this even more efficient we can also use
BackedStringViews to avoid copies, avoiding heap allocations for
transient data.
before:
Benchmark 1: nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
Time (mean ± σ): 6.952 s ± 0.015 s [User: 5.294 s, System: 1.452 s]
Range (min … max): 6.926 s … 6.974 s 10 runs
after:
Benchmark 1: nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
Time (mean ± σ): 6.907 s ± 0.012 s [User: 5.272 s, System: 1.429 s]
Range (min … max): 6.893 s … 6.926 s 10 runs
istream sentry objects are very expensive for single-character
operations, and since we don't configure exception masks for the
istreams used here they don't even do anything. all we need is
end-of-string checks and an advancing position in an immutable memory
buffer, both of which can be had for much cheaper than istreams allow.
the effect of this change is most apparent on empty stores.
before:
Benchmark 1: nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
Time (mean ± σ): 7.167 s ± 0.013 s [User: 5.528 s, System: 1.431 s]
Range (min … max): 7.147 s … 7.182 s 10 runs
after:
Benchmark 1: nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
Time (mean ± σ): 6.963 s ± 0.011 s [User: 5.330 s, System: 1.421 s]
Range (min … max): 6.943 s … 6.974 s 10 runs
as written the comparisons generate copies, even though it looks as
though they shouldn't.
before:
Time (mean ± σ): 4.396 s ± 0.002 s [User: 3.894 s, System: 0.501 s]
Range (min … max): 4.393 s … 4.399 s 10 runs
after:
Time (mean ± σ): 4.260 s ± 0.003 s [User: 3.754 s, System: 0.505 s]
Range (min … max): 4.257 s … 4.266 s 10 runs
resizing a std::string clears the newly added bytes, which is not
necessary here and comes with a ~1.4% slowdown on our test nixos config.
〉 nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
before:
Time (mean ± σ): 4.486 s ± 0.003 s [User: 3.978 s, System: 0.507 s]
Range (min … max): 4.482 s … 4.492 s 10 runs
after:
Time (mean ± σ): 4.429 s ± 0.002 s [User: 3.929 s, System: 0.500 s]
Range (min … max): 4.427 s … 4.433 s 10 runs
`eval-system` option overrides just the value of `builtins.currentSystem`.
This is more useful than overriding `system` since you can build these
derivations on remote builders which can work on the given system.
Co-authored-by: John Ericson <John.Ericson@Obsidian.Systems>
Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>
I wrote the `configure.ac` wrong, and so we just got no builds
supporting ACLs.
Also, it needs to be more precise because Darwin puts other stuff in
that same header, evidently.
I don't love the way this code looks. There are two larger problems:
- eval, build/scratch, destination stores (#5025) should have different
types to reflect the fact that they are used for different purposes
and those purposes correspond to different operations. It should be
impossible to "use the wrong store" in my cases.
- Since drvs can end up in both the eval and build/scratch store, we
should have some sort of union/layered store (not on the file sytem
level, just conceptual level) that allows accessing both. This would
get rid of the ugly "check both" boilerplate in this PR.
Still, it might be better to land this now / soon after minimal cleanup,
so we have a concrete idea of what problem better abstractions are
supposed to solve.
Below the comment added by this commit is a much longer comment
followed by a trust check, both of which have confused me on at
least two occasions. I figured it out once, forgot it, then had to
ask @Ericson2314 to explain it, at which point I understood it
again. I think this might confuse other people too, or maybe I will
just forget it a third time. So let's add a comment.
Farther down in the function is the following check:
```
if (!(drvType.isCA() || trusted))
throw Error("you are not privileged to build input-addressed derivations");
```
This seems really strange at first. A key property of Nix is that
you can compute the outpath of a derivation using the derivation
(and its references-closure) without trusting anybody!
The missing insight is that at this point in the code the builder
doesn't necessarily have the references-closure of the derivation
being built, and therefore needs to trust that the derivation's
outPath is honest. It's incredibly easy to overlook this, because
the only difference between these two cases is which of these
identically-named functions we used:
- `readDerivation(Source,Store)`
- `Store::readDerivation()`
These functions have different trust models (except in the special
case where the first function is used on the local store). We
should call the reader's attention to this fact.
Co-authored-by: Cole Helbling <cole.e.helbling@outlook.com>
In https://github.com/NixOS/nix/pull/6134#issuecomment-1079199888,
@thuffschmitt proposed exposing `LegacySSHStore` in Nix for
deduplication with Hydra, at least temporarily. I think that is a good
idea.
Note that the diff will look bad unless one ignores whitespace! Also try
this locally:
```shell-session
git diff --ignore-all-space HEAD^:src/libstore/legacy-ssh-store.cc HEAD:src/libstore/legacy-ssh-store.cc
git diff --ignore-all-space HEAD^:src/libstore/legacy-ssh-store.cc HEAD:src/libstore/legacy-ssh-store.hh
```
This is needed for building CA deriations with a src store / dest store
split. In particular it is needed for Hydra.
https://github.com/NixOS/hydra/issues/838 currently puts realizations,
and thus build outputs, in the local store, but it should not.
In the process, partially undo e89b5bd0bf
in that the ancient < 2.4 version is now supported again by the
serializer again. `LegacySSHStore`, instead of also asserting that the
version is at least 4, just checks that `narHash` is set.
This allows us to better test the serializer in isolation for both
versions (< 4 and >= 4).
- remove prose for the default value, which is shown programmatically
- add note on how this relates to `cores`
- add link to mentioned derivation attribute
Today, with the tests inside a `tests` intermingled with the
corresponding library's source code, we have a few problems:
- We have to be careful that wildcards don't end up with tests being
built as part of Nix proper, or test headers being installed as part
of Nix proper.
- Tests in libraries but not executables is not right:
- It means each executable runs the previous unit tests again, because
it needs the libraries.
- It doesn't work right on Windows, which doesn't want you to load a
DLL just for the side global variable . It could be made to work
with the dlopen equivalent, but that's gross!
This reorg solves these problems.
There is a remaining problem which is that sibbling headers (like
`hash.hh` the test header vs `hash.hh` the main `libnixutil` header) end
up shadowing each other. This PR doesn't solve that. That is left as
future work for a future PR.
Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>
This makes for more useful manual table of contents, that displays the
information at a glance.
The `nix help-stores` command is kept as-is, even though it will show up
in the manual with the same information as these pages due to the way it
is written as a "`--help`-style" command. Deciding what to do with that
command is left for a later PR.
This change also lists all store types at the top of the respective overview page.
Co-authored-by: John Ericson <John.Ericson@Obsidian.Systems
The problem was that f880469173 forgot
that the `#include <sys/xattr.h>` was guarded by an `#ifdef __linux__`.
However, the build failure was only on FreeBSD --- turns out other
platforms have this header too!
The fix therefore uses a new configure check so we properly clear ACLs
on more platforms.
`installcheck` doesn't yet work, but the rest of the build can now
happen mostly inside a separate build directory.
Progress on #9342
Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>
It is not inherently tied to `LocalStore`, it could probably even go in
`libnixutil`. Functions not attached to `LocalStore` should not be
declared in `local-store.hh`.
I am moving it to facilitate experimenting for #9344. If
canonicalisation should be done client-side in client-side builds, there
wouldn't be a `LocalStore` at all so having to include that header to
get this freestanding function is cumbersome and wrong.
Perhaps canonicalisation should still be done server-side for security
reasons --- I don't mean to make that judgement call now --- but even if
so, this freestanding function still isn't connected to `LocalStore` so
while less urgent it is still better to move out of this header.
This avoids repeated copying of the same source tree between Nix
invocations. It requires the accessor to have a "fingerprint" (e.g. a
Git revision) that uniquely determines its contents.
Closes#9343
See that issue for motivation.
Installing these is disabled by default, but we enable it (and the
additional output we want isntall these too so as not to clutter the
existing ones) to use in cross builds and dev shells.
Before it returned a list of JSON objects with store object information,
including the path in each object. Now, it maps the paths to JSON
objects with the metadata sans path.
This matches how `nix derivation show` works.
Quite hillariously, none of our existing functional tests caught this
change to `path-info --json` though they did use it. So just new
functional tests need to be added.
`Store::pathInfoToJSON` was a rather baroque functions, being full of
parameters to support both parsed derivations and `nix path-info`. The
common core of each, a simple `dValidPathInfo::toJSON` function, is
factored out, but the rest of the logic is just duplicated and then
specialized to its use-case (at which point it is no longer that
duplicated).
This keeps the human oriented CLI logic (which is currently unstable)
and the core domain logic (export reference graphs with structured
attrs, which is stable), separate, which I think is better.
Spent a while debugging why `nix-copy-closure` wasn't working anymore
and it was my shell RC printing something I added for debug.
Hopefully this can save someone else some time.
All OS and IO operations should be moved out, leaving only some misc
portable pure functions.
This is useful to avoid copious CPP when doing things like Windows and
Emscripten ports.
Newly exposed functions to break cycles:
- `restoreSignals`
- `updateWindowSize`
When doing local builds, we get phase reporting lines in the log file,
they look like '@nix {"action":"setPhase","phase":"unpackPhase"}'.
With the ssh-ng protocol, we do have access to these messages, but since we
are only including messages of type resBuildLogLine in the logs, the phase
information does not end up in the log file.
The phase reporting could probably be improved altoghether (it looks like it
is kind of accidental that these JSON messages for phase reporting show up
but others don't, just because they are actually emitted by nixpkgs' stdenv),
but as a first step I propose to make ssh-ng behave in the same way as local builds do.
Deduplicating code moreover enforcing the pattern means:
- It is easier to write new characterization tests because less boilerplate
- It is harder to mess up new tests because there are fewer places to
make mistakes.
Co-authored-by: Jacek Galowicz <jacek@galowicz.de>
