With Linux kernel >=6.6 & glibc 2.39 a `fchmodat2(2)` is available that
isn't filtered away by the libseccomp sandbox.
Being able to use this to bypass that restriction has surprising results
for some builds such as lxc[1]:
> With kernel ≥6.6 and glibc 2.39, lxc's install phase uses fchmodat2,
> which slips through 9b88e52846/src/libstore/build/local-derivation-goal.cc (L1650-L1663).
> The fixupPhase then uses fchmodat, which fails.
> With older kernel or glibc, setting the suid bit fails in the
> install phase, which is not treated as fatal, and then the
> fixup phase does not try to set it again.
Please note that there are still ways to bypass this sandbox[2] and this is
mostly a fix for the breaking builds.
This change works by creating a syscall filter for the `fchmodat2`
syscall (number 452 on most systems). The problem is that glibc 2.39
is needed to have the correct syscall number available via
`__NR_fchmodat2` / `__SNR_fchmodat2`, but this flake is still on
nixpkgs 23.11. To have this change everywhere and not dependent on the
glibc this package is built against, I added a header
"fchmodat2-compat.hh" that sets the syscall number based on the
architecture. On most platforms its 452 according to glibc with a few
exceptions:
$ rg --pcre2 'define __NR_fchmodat2 (?!452)'
sysdeps/unix/sysv/linux/x86_64/x32/arch-syscall.h
58:#define __NR_fchmodat2 1073742276
sysdeps/unix/sysv/linux/mips/mips64/n32/arch-syscall.h
67:#define __NR_fchmodat2 6452
sysdeps/unix/sysv/linux/mips/mips64/n64/arch-syscall.h
62:#define __NR_fchmodat2 5452
sysdeps/unix/sysv/linux/mips/mips32/arch-syscall.h
70:#define __NR_fchmodat2 4452
sysdeps/unix/sysv/linux/alpha/arch-syscall.h
59:#define __NR_fchmodat2 562
I added a small regression-test to the setuid integration-test that
attempts to set the suid bit on a file using the fchmodat2 syscall.
I confirmed that the test fails without the change in
local-derivation-goal.
Additionally, we require libseccomp 2.5.5 or greater now: as it turns
out, libseccomp maintains an internal syscall table and
validates each rule against it. This means that when using libseccomp
2.5.4 or older, one may pass `452` as syscall number against it, but
since it doesn't exist in the internal structure, `libseccomp` will refuse
to create a filter for that. This happens with nixpkgs-23.11, i.e. on
stable NixOS and when building Lix against the project's flake.
To work around that
* a backport of libseccomp 2.5.5 on upstream nixpkgs has been
scheduled[3].
* the package now uses libseccomp 2.5.5 on its own already. This is to
provide a quick fix since the correct fix for 23.11 is still a staging cycle
away.
We still need the compat header though since `SCMP_SYS(fchmodat2)`
internally transforms this into `__SNR_fchmodat2` which points to
`__NR_fchmodat2` from glibc 2.39, so it wouldn't build on glibc 2.38.
The updated syscall table from libseccomp 2.5.5 is NOT used for that
step, but used later, so we need both, our compat header and their
syscall table 🤷
Relevant PRs in CppNix:
* https://github.com/NixOS/nix/pull/10591
* https://github.com/NixOS/nix/pull/10501
[1] https://github.com/NixOS/nixpkgs/issues/300635#issuecomment-2031073804
[2] https://github.com/NixOS/nixpkgs/issues/300635#issuecomment-2030844251
[3] https://github.com/NixOS/nixpkgs/pull/306070
(cherry picked from commit ba6804518772e6afb403dd55478365d4b863c854)
Change-Id: I6921ab5a363188c6bff617750d00bb517276b7fe
This commit makes Meson the default buildsystem for Lix.
The Make buildsystem is now deprecated and will be removed soon, but has
not yet, which will be done in a later commit when all seems good. The
mesonBuild jobs have been removed, and have not been replaced with
equivalent jobs to ensure the Make buildsystem still works.
The full, new commands in a development shell are:
$ meson setup ./build "--prefix=$out" $mesonFlags
(A simple `meson setup ./build` will also build, but will do a different
thing, not having the settings from package.nix applied.)
$ meson compile -C build
$ meson test -C build --suite=check
$ meson install -C build
$ meson test -C build --suite=installcheck
(Check and installcheck may both be done after install, allowing you to
omit the --suite argument entirely, but this is the order package.nix
runs them in.)
If tests fail and Meson helpfully has no output for why, use the
`--print-error-logs` option to `meson test`. Why this is not the default
I cannot explain.
If you change a setting in the buildsystem, most cases will
automatically regenerate the Meson configuration, but some cases, like
trying to build a specific target whose name is new to the buildsystem
(e.g. `meson compile -C build src/libmelt/libmelt.dylib`, when
`libmelt.dylib` did not exist as a target the last time the buildsystem
was generated), then you can reconfigure using new settings but
existing options, and only recompiling stuff affected by the changes:
$ meson setup --reconfigure build
Note that changes to the default values in `meson.options` or in the
`default_options :` argument to project() are NOT propagated with
`--reconfigure`.
If you want a totally clean build, you can use:
$ meson setup --wipe build
That will work regardless of if `./build` exists or not.
Specific, named targets may be addressed in
`meson build -C build <target>` with the "target ID" if there is one,
which is the first string argument passed to target functions that
have one, and unrelated to the variable name, e.g.:
libexpr_dylib = library('nixexpr', …)
can be addressed with:
$ meson compile -C build nixexpr
All targets may be addressed as their output, relative to the build
directory, e.g.:
$ meson compile -C build src/libexpr/libnixexpr.so
But Meson does not consider intermediate files like object files
targets. To build a specific object file, use Ninja directly and
specify the output file relative to the build directory:
$ ninja -C build src/libexpr/libnixexpr.so.p/nixexpr.cc.o
To inspect the canonical source of truth on what the state of the
buildsystem configuration is, use:
$ meson introspect
Have fun!
Change-Id: Ia3e7b1e6fae26daf3162e655b4ded611a5cd57ad
This commit adds the capability for building the Doxygen internal API
docs in the Meson buildsystem, and also makes doing so the default for
the internal-api-docs hydra job. Aside from the /nix-support directory,
which differed only by the hash part of a store path, the outputs of
hydraJobs.internal-api-docs before and after this commit were
bit-for-bit identical on my machine.
Change-Id: I98f0017891c25b06866c15f7652fe74f706ec8e1
This is in our style guide, we can cheaply enforce it, let's do it.
```
$ pre-commit
check-case-conflicts.....................................................Passed
check-executables-have-shebangs..........................................Passed
check-headers............................................................Failed
- hook id: check-headers
- exit code: 1
Missing pattern @file in file src/libexpr/value.hh
We found some header files that don't conform to the style guide.
The Lix style guide requests that header files:
- Begin with `#pragma once` so they only get parsed once
- Contain a doxygen comment (`/**` or `///`) containing `@file`, for
example, `///@file`, which will make doxygen generate docs for them.
When adding that, consider also adding a `@brief` with a sentence
explaining what the header is for.
For more details: https://wiki.lix.systems/link/3#bkmrk-header-files
check-merge-conflicts....................................................Passed
check-shebang-scripts-are-executable.....................................Passed
check-symlinks.......................................(no files to check)Skipped
end-of-file-fixer........................................................Passed
mixed-line-endings.......................................................Passed
no-commit-to-branch......................................................Passed
release-notes........................................(no files to check)Skipped
treefmt..................................................................Passed
trim-trailing-whitespace.................................................Passed
```
Fixes: https://git.lix.systems/lix-project/lix/issues/233
Change-Id: I77150b9298c844ffedd0f85cc5250ae9208502e3
The flake for pre-commit-checks is rather questionable. We ignored
it so it uses our own nixpkgs and doesn't reimport nixpkgs. This should
save a couple of seconds of eval time!
Change-Id: I4584982beb32e0122f791fa29f6a544bdbb9e201
package.nix previously needed this callPackage'd externally, which
didn't make a lot of sense to us since this is an internal dependency.
Thus we changed it to make it more self contained.
Change-Id: I4935bc0bc80e1a132bc9b1519e917791da95037c
Some of this code existed for installer tests, and indeed its removal is
an indication that our daemon cross-compatibility tests were removed.
Although these are not like, super critical tests, we would like to
restore them.
See: https://git.lix.systems/lix-project/lix/issues/33
Change-Id: I75c733b25c00eca3a9676d498703bbfc1d6ec21b
The following command is now sufficient to build Lix from outside of the
flake:
nix-build -E 'let pkgs = import <nixpkgs> { }; in pkgs.callPackage
./package.nix { build-release-notes = false; nix-doc = pkgs.callPackage
./nix-doc/package.nix { }; }'
Change-Id: Ie6b14b446480ac07c7266d4fba20042b04cc35b9
follow-up to 32eaa8a29[1] "flake: move release note checks to hydraJobs",
this commit fixes a load-bearing typo for`checks.rl-next` and
`checks.rl-next-dev`.
[1]: 32eaa8a2910793538deab31f85534faf7e722ef7
Change-Id: I9383ed21f7eccc337c0c2f65525418b735a94a1d
In our view it really doesn't make sense to not have this in in
package.nix in some way. These patches aren't just for performance or
something -- Lix flat out doesn't build without these patches.
(Arguably that makes them a buildsystem responsibility as well, but that
can wait for when we're ready to start adding subproject fallback
dependency resolution to Meson.)
This is a step towards making `package.nix` more self-sufficient and
`callPackage`able without excessive external logic.
With this change the following command is enough to build Lix from out
of the flake:
nix-build -E 'let pkgs = import <nixpkgs> { }; in pkgs.callPackage
./package.nix { build-release-notes = false; inherit (pkgs.lib) fileset;
nix-doc = pkgs.callPackage ./nix-doc/package.nix { }; }'
Change-Id: Ia37fe8171f87d3293033de8be07d9bab12716f1d
having them in checks only does not run them in CI, which can cause
broken release notes entries to pass.
fixes#228
Change-Id: If0ba7b1be0b6525fc884a27e941cbc84b5a160f9
For a long time `nix repl` has supported displaying documentation set on
builtins, however, it has long been convention to use Markdown comments
on Nix functions themselves for documentation. This exposes that
information to `nix repl` users in a nice and formatted way.
NixOS/rfcs#145 doc-comments are primarily what this feature is intended
to consume, however, support for lambda documentation in the repl is
experimental. We do our best effort to support the RFC here.
These changes are based on [the nix-doc library](https://github.com/lf-/nix-doc) and
are licensed under the terms described in the relevant source files.
Change-Id: Ic6fe947d39a22540705d890737e336c4720b0a22
Meson fails to setup when cmake is not found.
Add cmake to the default devShell so meson build works.
Change-Id: I4d933efac9540c564f3171e43c23e7a645722ef7
The big ones here are `trim-trailing-whitespace` and `end-of-file-fixer`
(which makes sure that every file ends with exactly one newline
character).
Change-Id: Idca73b640883188f068f9903e013cf0d82aa1123
I didn't enable this by default for clang due to making the build time
10% worse or so. Unfortunate, but tbh devs for whom 10% of build time is
not *that* bad should probably simply enable this.
Change-Id: I8d1e5b6f3f76c649a4e2f115f534f7f97cee46e6
hacking changelog-d to support not just github but also forgejo and
gerrit is a lot more complicated than it's worth, even moreso since
the entire thing can just as well be done with ~60 lines of python.
this new script is also much cheaper to instantiate (being python),
so having it enabled in all shells is far less of a hassle.
we've also adjusted existing release notes that referenced a gerrit
cl to auto-link to the cl in question, making the diff a bit bigger
closes https://git.lix.systems/lix-project/lix/issues/176
Change-Id: I8ba7dd0070aad9ba4474401731215fcf5d9d2130
parallel meson builds need too much ram. linearize them for now, and
hopefully we can remove the make build system and this hack soonish.
Change-Id: I42c092db8b0c63680e77da2263cdfe9e7f6575be
This commit adds several meson.build, which successfully build and
install Lix executables, libraries, and headers. Meson does not yet
build docs, Perl bindings, or run tests, which will be added in
following commits. As such, this commit does not remove the existing
build system, or make it the default, and also as such, this commit has
several FIXMEs and TODOs as notes for what should be done before the
existing autoconf + make buildsystem can be removed and Meson made the
default. This commit does not modify any source files.
A Meson-enabled build is also added as a Hydra job, and to
`nix flake check`.
Change-Id: I667c8685b13b7bab91e281053f807a11616ae3d4
pkgs.pkgsStatic.glibcLocales is null, so the string coercion was failing
for devShells against static stdenvs
Change-Id: Iee8e1042a852133ce0432627d72a85e97c17055e
`macOS` does not have `glibcLocales`:
error:
… while calling the 'derivationStrict' builtin
at /derivation-internal.nix:9:12:
8|
9| strict = derivationStrict drvAttrs;
| ^
10|
… while evaluating derivation 'nix-2.90.0'
whose name attribute is located at /nix/store/y0c95bwyvs80pm69hdd4b11pyq2ghiwh-source
/pkgs/stdenv/generic/make-derivation.nix:348:7
… while evaluating attribute 'LOCALE_ARCHIVE' of derivation 'nix-2.90.0'
at /nix/store/ng5qzbyv4902b4pw7g35caqw5cnmryf9-source/flake.nix:331:15:
330| # Required to make non-NixOS Linux not complain about missing loc
Change-Id: I4464484a0eca12b5e073d49d900b6f25886245c1
This series takes a somewhat different approach from the flake rework
done in NixOS/nix. The package.nix here does not provide callPackage
options for all the various settings in the build, and instead the other
places Nix derivations are used (like internal-api-docs) will .overrideAttrs
the normal Nix package derivation. This more closely matches how these
things were structured originally, and results in less churn and more
atomicity in these changes.
In the future, package.nix likely will migrate to have more build
options in the callPackage arguments, but we are also planning to
rewrite the build system anyway.
Change-Id: I170c4e5a4184bab62e1fd75e56db876d4ff116cf
deduplication does not currently work fully, showing derivations
multiple times if they have different underlying values. this can happen
by selecting the same derivation twice for two different attributes of a
set, using inherit-from (which reduces to the previous), importing
nixpkgs twice, or any other number of things.
since users already have to deal with duplicates for this reason it
won't hurt to add *more* duplicates. the alternative would be to
deduplicate fully, which would drop derivations that are currently
returned and those pose a regression risk.
Change-Id: I64b397351237e10375d270f1bddecb71f62aa131
Just `stdenv.isDarwin` isn't enough because it doesn't apply to the
build platform, which mean that cross packages building from darwin to
another platform will have `isDarwin` set to false.
Replace it by `stdenv.buildPlatform.isDarwin`.
(cherry picked from commit a0cb75d96f76a3be48b9319e26d8ad78ef4e4525)
(h/t jade for finding this one)
Change-Id: If3cb74e6feaa5d51de550d9a140c71683c2214cd
