This makes 'nix develop' set the Linux personality in the same way
that the actual build does, allowing a command like 'nix develop
nix#devShells.i686-linux.default' on x86_64-linux to work correctly.
These only functioned if a very narrow combination of conditions held:
- The result path does not yet exist (--check did not result in
repeated builds), AND
- The result path is not available from any configured substituters, AND
- No remote builders that can build the path are available.
If any of these do not hold, a derivation would be built 0 or 1 times
regardless of the repeat option. Thus, remove it to avoid confusion.
We shouldn't skip this if the supplementary group list is empty,
because then the sandbox won't drop the supplementary groups of the
parent (like "root").
The new experimental feature 'cgroups' enables the use of cgroups for
all builds. This allows better containment and enables setting
resource limits and getting some build stats.
It occurred when a output of the dependency was already available,
so it didn't need rebuilding and didn't get added to the
inputDrvOutputs.
This process-related info wasn't suitable for the purpose of finding
the actual input paths for the builder. It is better to do this in
absolute terms by querying the store.
Cgroups are now only used for derivations that require the uid-range
range feature. This allows auto UID allocation even on systems that
don't have cgroups (like macOS).
Also, make things work on modern systems that use cgroups v2 (where
there is a single hierarchy and no "systemd" controller).
Call it as `['nix', '__build-remote', ... ]` rather than the previous
`["__build-remote", "nix __build-remote", ... ]` which seemed to have
been most likely unintended
After we've send "\2\n" to the parent, we can't send a serialized
exception anymore. It will show up garbled like
$ nix-build --store /tmp/nix --expr 'derivation { name = "foo"; system = "x86_64-linux"; builder = "/foo/bar"; }'
this derivation will be built:
/nix/store/xmdip0z5x1zqpp6gnxld3vqng7zbpapp-foo.drv
building '/nix/store/xmdip0z5x1zqpp6gnxld3vqng7zbpapp-foo.drv'...
ErrorErrorEexecuting '/foo/bar': No such file or directory
error: builder for '/nix/store/xmdip0z5x1zqpp6gnxld3vqng7zbpapp-foo.drv' failed with exit code 1
readDerivation is pretty slow, and while it may not be significant for
some use cases, on things like ghc-nix where we have thousands of
derivations is really slows things down.
So, this just doesn’t do the impure derivation check if the impure
derivation experimental feature is disabled. Perhaps we could cache
the result of isPure() and keep the check, but this is a quick fix to
for the slowdown introduced with impure derivations features in 2.8.0.
RewritingSink can handle being fed input where a reference crosses a
chunk boundary. we don't need to load the whole source into memory, and
in fact *not* loading the whole source lets nix build FODs that do not
fit into memory (eg fetchurl'ing data files larger than system memory).
Once a derivation goal has been completed, we check whether or not
this goal was meant to be repeated to check its output.
An early return branch was preventing the worker to reach that repeat
code branch, hence breaking the --check command (#2619).
It seems like this early return branch is an artifact of a passed
refactoring. As far as I can tell, buildDone's main branch also
cleanup the tmp directory before returning.
The workaround for "Some distros patch Linux" mentioned in
local-derivation-goal.cc will not help in the `--option
sandbox-fallback false` case. To provide the user more helpful
guidance on how to get the sandbox working, let's check to see if the
`/proc` node created by the aforementioned patch is present and
configured in a way that will cause us problems. If so, give the user
a suggestion for how to troubleshoot the problem.
local-derivation-goal.cc contains a comment stating that "Some distros
patch Linux to not allow unprivileged user namespaces." Let's give a
pointer to a common version of this patch for those who want more
details about this failure mode.
This commit causes nix to `warn()` if sandbox setup has failed and
`/proc/self/ns/user` does not exist. This is usually a sign that the
kernel was compiled without `CONFIG_USER_NS=y`, which is required for
sandboxing.
This commit uses `warn()` to notify the user if sandbox setup fails
with errno==EPERM and /proc/sys/user/max_user_namespaces is missing or
zero, since that is at least part of the reason why sandbox setup
failed.
Note that `echo -n 0 > /proc/sys/user/max_user_namespaces` or
equivalent at boot time has been the recommended mitigation for
several Linux LPE vulnerabilities over the past few years. Many users
have applied this mitigation and then forgotten that they have done
so.
The failure modes for nix's sandboxing setup are pretty complicated.
When nix is unable to set up the sandbox, let's provide more detail
about what went wrong. Specifically:
* Make sure the error message includes the word "sandbox" so the user
knows that the failure was related to sandboxing.
* If `--option sandbox-fallback false` was provided, and removing it
would have allowed further attempts to make progress, let the user
know.
With this, Nix will write a copy of the sandbox shell to /bin/sh in
the sandbox rather than bind-mounting it from the host filesystem.
This makes /bin/sh work out of the box with nix-static, i.e. you no
longer get
/nix/store/qa36xhc5gpf42l3z1a8m1lysi40l9p7s-bootstrap-stage4-stdenv-linux/setup: ./configure: /bin/sh: bad interpreter: No such file or directory
Linus Heckemann
Yorick
Robert Hensing