Because of an objc quirk[1], calling curl_global_init for the first time
after fork() will always result in a crash.
Up until now the solution has been to set
OBJC_DISABLE_INITIALIZE_FORK_SAFETY for every nix process to ignore
that error.
This is less than ideal because we were setting it in package.nix,
which meant that running nix tests locally would fail because
that variable was not set.
Instead of working around that error we address it at the core -
by calling curl_global_init inside initLibStore, which should mean
curl will already have been initialized by the time we try to do so in
a forked process.
[1] 01edf1705f/runtime/objc-initialize.mm (L614-L636)
Change-Id: Icf26010a8be655127cc130efb9c77b603a6660d0
only two users of this function exist. only one used it in a way that
even bears resemblance to asynchronicity, and even that one didn't do
it right. fully async and parallel computation would have only worked
if any getEdgesAsync never calls the continuation it receives itself,
only from more derived callbacks running on other threads. calling it
directly would cause the decoupling promise to be awaited immediately
*on the original thread*, completely negating all nice async effects.
Change-Id: I0aa640950cf327533a32dee410105efdabb448df
this seems to be an oversight, considering that regular substitutions
are concurrency-limited. while not particularly necessary at present,
once we've removed the `Callback` based interfaces it will be needed.
Change-Id: Ide2d08169fcc24752cbd07a1d33fb8482f7034f5
When /nix/var (or, more precisely, NIX_STATE_DIR) does not exist at all,
Lix falls back to creating an adhoc chroot store in XDG_DATA_HOME.
b247ef72d[1] changed the way Store classes are initialized, and in the
migration, a `params2` was accidentally changed to `params`. This commit
restores the correct behavior, and in lieu of a single *character* fix,
this commit also changes the variable name to something more reasonable.
Fixes#274.
[1]: b247ef72dc
n.b., this code might deserve some more looking at anyway. this fallback
store creation throws away *all* Store params passed to
openFromNonUri() in favor of an entirely new set which only contains
the `root` param, which may or may not be the correct behavior
Change-Id: Ibea559b88a50e6d6e75a1f87d9d7816cabb2a8f3
As per our bootstrap governance discussions, here's a very simple
proposal which links as much as possible to our wiki.
Change-Id: I88b1c43f933ff7e529151b1e933fad40283383c4
Signed-off-by: Raito Bezarius <raito@lix.systems>
returning 0 from the callback for errors signals successful transfer if
the source returned no data even though the exception we've just caught
clearly disagrees. while this is not all that important (since the only
viable cause of such errors will be dataCallback, and the sole instance
of it being used already takes care of exceptions) we can just do this.
Change-Id: I2bb150eff447121d82e8e3aa4e00057c40523ac6
this will be necessary if we want download() to return a source instead
of consuming a sink, which will in turn be needed to remove coroutines.
Change-Id: I34ec241e9bbc5d32fbcd243b244e29c3757533aa
Some tests were failing on darwin,
if the auto-allocate-uids featrure was enabled.
This was because AAU on darwin works by setuid-ing as a non-existent
user, so the tests that were relying on `whoami` were failing.
In the case of trusted-users we fall back to printing the user id,
which is already handled gracefully in the daemon code - i.e. when
a user does not exist or for some other reason looking up their
username is not possible, the daemon falls back to searching for their
uid inside the trusted-users list.
When whoami is used to print the username for other purpose,
we default to printing nixbld.
Change-Id: Ib61615677565098cb5fbf5e26a946ef427c58caf
This doesn't comprehensively fix everything outdated in the manual, or
make the manual greatly better, but it does note down where at least
jade noticed it was wrong, and it does fix all the instances of
referencing Nix to conform to the style guide to the best of our
ability.
A lot of things have been commented out for being wrong, and there are
three types of FIXME introduced:
- FIXME(Lix): generically Lix needs to fix it
- FIXME(Qyriad): re lix-project/lix#215
- FIXME(meson): docs got outdated by meson changes and need rewriting
I did fix a bunch of it that I could, but there could certainly be
mistakes and this is definitely just an incremental improvement.
Fixes: lix-project/lix#266
Change-Id: I5993c4603d7f026a887089fce77db08394362135
sizeof(long) is 4 bytes on i686 GCC.
With ~32 GiB of memory and a page size of 4096, there are 7988420 pages.
(7988420 * 4096) is bigger than INT32_MAX folks.
This has gone unnoticed for 9 years, and only came up thanks to
94ea517db[1] adding integer overflow sensitization checks, which caused
this broken code to emit an illegal instruction, crashing Lix the
instant the buildsystem ran Lix to generate the docs files.
[1]: 94ea517dbe729765b69638190f4bea3f6a632b40
Change-Id: I50bb9ea072aac11b449d79e5d55525887a6e5a99
not doing this will cause transfers that had their readers disappear to
linger. with lingering transfers the curl thread can't shut down, which
will cause nix itself to not shut down until the transfer finishes some
other way (most likely network timeouts). also add a new test for this.
Change-Id: Id2401b3ac85731c824db05918d4079125be25b57
mdbook has the unfortunate habit of creating stub files for chapters it
can't find on disk. turn off this helpful feature as it masks errors in
the summary file, and fix a recently introduced instance of this error.
Change-Id: I10d86aac0489c9c494bd5c8a50047415f4d4b18d
If unprivileged userns are *believed* to be disabled (such as with
"kernel.unprivileged_userns_clone = 0"), Lix would previously *give up*
on trying to use a user namespace before actually trying it, even if, in
cases such as unprivileged_userns_clone, it would actually be allowed
since Nix has CAP_SYS_ADMIN when running as daemon.
(see, e.g. 25d4709a4f)
We changed it to actually try it first, and then diagnose possible
causes, and also to be more loud about the whole thing, using warnings
instead of debugs. These warnings will only print on the first build run
by the daemon, which is, tbh, eh, shrug.
This is what led to us realizing that no-userns was a poorly exercised
condition.
Change-Id: I8e4f21afc89c574020dc7e89a560cc740ce6573a
This was found when `logrotate.conf` failed to build in a NixOS system
with:
/nix/store/26zdl4pyw5qazppj8if5lm8bjzxlc07l-coreutils-9.3/bin/id: cannot find name for group ID 30000
This was surprising because it seemed to mean that /etc/group was busted
in the sandbox. Indeed it was:
root❌0:
nixbld:!💯
nogroup❌65534:
We diagnosed this to sandboxUid() being called before
usingUserNamespace() was called, in setting up /etc/group inside the
sandbox. This code desperately needs refactoring.
We also moved the /etc/group code to be with the /etc/passwd code, but
honestly this code is all spaghetti'd all over the place and needs some
more serious tidying than we did here.
We also moved some checks to be earlier to improve locality with where
the things they are checking come from.
Change-Id: Ie29798771f3593c46ec313a32960fa955054aceb
This has the following downsides:
* you cannot build Lix against nixos-unstable.
* this will immediately break as soon as libseccomp will hit
nixos-23.11 (given that people will probably use the package.nix via
our overlay or override nixpkgs via `follows`).
Hence, removing the assert again and add a better FIXME comment.
Change-Id: I284e10cf08e1873fef70ed869a1638aa89792422
This reverts commit a8b3d777fb.
This undoes the revert of PR#6621, which allows nested `follows`, i.e.
{
inputs = {
foo.url = "github:bar/foo";
foo.inputs.bar.inputs.nixpkgs = "nixpkgs";
};
}
does the expected thing now. This is useful to avoid the 1000 instances
of nixpkgs problem without having each flake in the dependency tree to
expose all of its transitive dependencies for modification.
This was in fact part of Nix before and the C++ changes applied w/o
conflicts. However, it got reverted then because people didn't want to
merge lazy-trees against it which was supposed to be merged soon back in
October 2022.
Fixes: lix-project/lix#201
Change-Id: I5ddef914135b695717b2ef88862d57ced5e7aa3c
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
Nikodem Rabuliński
Patrick Jackson
Qyriad
eldritch horrors
jade
raito
Maximilian Bosch