Unsetting `build-users-group` (without `auto-allocate-uids` enabled)
gives the following error:
```
src/libstore/lock.cc:25: static std::unique_ptr<nix::UserLock> nix::SimpleUserLock::acquire(): Assertion `settings.buildUsersGroup != ""' failed.
```
Fix the logic in `useBuildUsers` and document the default value
for `build-users-group`.
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.
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).
I just had a colleague get confused by the previous phrase for good
reason. "valid" sounds like an *objective* criterion, e.g. and *invalid
signature* would be one that would be trusted by no one, e.g. because it
misformatted or something.
What is actually going is that there might be a signature which is
perfectly valid to *someone else*, but not to the user, because they
don't trust the corresponding public key. This is a *subjective*
criterion, because it depends on the arbitrary and personal choice of
which public keys to trust.
I therefore think "trustworthy" is a better adjective to use. Whether
something is worthy of trust is clearly subjective, and then "trust"
within that word nicely evokes `trusted-public-keys` and friends.
Starting work on #5638
The exact boundary between `FetchSettings` and `EvalSettings` is not
clear to me, but that's fine. First lets clean out `libstore`, and then
worry about what, if anything, should be the separation between those
two.
Because the manual is generated from default values which are themselves
generated from various sources (cpuid, bios settings (kvm), number of
cores). This commit hides non-reproducible settings from the manual
output.
Rather than having them plain strings scattered through the whole
codebase, create an enum containing all the known experimental features.
This means that
- Nix can now `warn` when an unkwown experimental feature is passed
(making it much nicer to spot typos and spot deprecated features)
- It’s now easy to remove a feature altogether (once the feature isn’t
experimental anymore or is dropped) by just removing the field for the
enum and letting the compiler point us to all the now invalid usages
of it.
Some people want to avoid using registries at all on their system; Instead
of having to add --no-registries to every command, this commit allows to
set use-registries = false in the config. --no-registries is still allowed
everywhere it was allowed previously, but is now deprecated.
Co-authored-by: Eelco Dolstra <edolstra@gmail.com>
They are equivalent according to
<https://spec.commonmark.org/0.29/#hard-line-breaks>,
and the trailing spaces tend to be a pain (because the make git
complain, editors tend to want to remove them − the `.editorconfig`
actually specifies that − etc..).
Since 0744f7f, it is now useful to have cache.nixos.org in substituers
even if /nix/store is not the Nix Store Dir. This can always be
overridden via configuration, though.
macOS systems with ARM64 can utilize a translation layer at
/Library/Apple/usr/libexec/oah to run x86_64 binaries. This change
makes Nix recognize that and it to "extra-platforms". Note that there
are two cases here since Nix could be built for either x86_64 or
aarch64. In either case, we can switch to the other architecture.
Unfortunately there is not a good way to prevent aarch64 binaries from
being run in x86_64 contexts or vice versa - programs can always
execute programs for the other architecture.
This removes the extra-substituters and extra-sandbox-paths settings
and instead makes every array setting extensible by setting
"extra-<name> = <value>" in the configuration file or passing
"--<name> <value>" on the command line.
This change provides support for using access tokens with other
instances of GitHub and GitLab beyond just github.com and
gitlab.com (especially company-specific or foundation-specific
instances).
This change also provides the ability to specify the type of access
token being used, where different types may have different handling,
based on the forge type.
`nix flake info` calls the github 'commits' API, which requires
authorization when the repository is private. Currently this request
fails with a 404.
This commit adds an authorization header when calling the 'commits' API.
It also changes the way that the 'tarball' API authenticates, moving the
user's token from a query parameter into the Authorization header.
The query parameter method is recently deprecated and will be disallowed
in November 2020. Using them today triggers a warning email.
Some users have their own hashed-mirrors setup, that is used to mirror
things in addition to what’s available on tarballs.nixos.org. Although
this should be feasable to do with a Binary Cache, it’s not always
easy, since you have to remember what "name" each of the tarballs has.
Continuing to support hashed-mirrors is cheap, so it’s best to leave
support in Nix. Note that NIX_HASHED_MIRRORS is also supported in
Nixpkgs through fetchurl.nix.
Note that this excludes tarballs.nixos.org from the default, as in
\#3689. All of these are available on cache.nixos.org.
This reduces memory consumption of
nix-instantiate \
-E 'with import <nixpkgs> {}; runCommand "foo" { src = ./blender; } "echo foo"' \
--option nar-buffer-size 10000
(where ./blender is a 1.1 GiB tree) from 1716 to 36 MiB, while still
ensuring that we don't do any write I/O for small source paths (up to
'nar-buffer-size' bytes). The downside is that large paths are now
always written to a temporary location in the store, even if they
produce an already valid store path. Thus, adding large paths might be
slower and run out of disk space. ¯\_(ツ)_/¯ Of course, you can always
restore the old behaviour by setting 'nar-buffer-size' to a very high
value.
"uid-range" provides 65536 UIDs to a build and runs the build as root
in its user namespace. "systemd-cgroup" allows the build to mount the
systemd cgroup controller (needed for running systemd-nspawn and NixOS
containers).
Also, add a configuration option "auto-allocate-uids" which is needed
to enable these features, and some experimental feature gates.
So to enable support for containers you need the following in
nix.conf:
experimental-features = auto-allocate-uids systemd-cgroup
auto-allocate-uids = true
system-features = uid-range systemd-cgroup
2^18 was overkill. The idea was to enable multiple containers to run
inside a build. However, those containers can use the same UID range -
we don't really care about perfect isolation between containers inside
a build.
Rather than rely on a nixbld group, we now allocate UIDs/GIDs
dynamically starting at a configurable ID (872415232 by default).
Also, we allocate 2^18 UIDs and GIDs per build, and run the build as
root in its UID namespace. (This should not be the default since it
breaks some builds. We probably should enable this conditional on a
requiredSystemFeature.) The goal is to be able to run (NixOS)
containers in a build. However, this will also require some cgroup
initialisation.
The 2^18 UIDs/GIDs is intended to provide enough ID space to run
multiple containers per build, e.g. for distributed NixOS tests.
Motivation: maintain project-level configuration files.
Document the whole situation a bit better so that it corresponds to the
implementation, and add NIX_USER_CONF_FILES that allows overriding
which user files Nix will load during startup.
This provides a pluggable mechanism for defining new fetchers. It adds
a builtin function 'fetchTree' that generalizes existing fetchers like
'fetchGit', 'fetchMercurial' and 'fetchTarball'. 'fetchTree' takes a
set of attributes, e.g.
fetchTree {
type = "git";
url = "https://example.org/repo.git";
ref = "some-branch";
rev = "abcdef...";
}
The existing fetchers are just wrappers around this. Note that the
input attributes to fetchTree are the same as flake input
specifications and flake lock file entries.
All fetchers share a common cache stored in
~/.cache/nix/fetcher-cache-v1.sqlite. This replaces the ad hoc caching
mechanisms in fetchGit and download.cc (e.g. ~/.cache/nix/{tarballs,git-revs*}).
This also adds support for Git worktrees (c169ea5904).
This is used to determine the dependency tree of impure libraries so nix
knows what paths to open in the sandbox. With the less restrictive
defaults it isn't needed anymore.
Before:
$ nix-channel --update
unpacking channels...
warning: SQLite database '/nix/var/nix/db/db.sqlite' is busy (SQLITE_PROTOCOL)
warning: SQLite database '/nix/var/nix/db/db.sqlite' is busy (SQLITE_PROTOCOL)
warning: SQLite database '/nix/var/nix/db/db.sqlite' is busy (SQLITE_PROTOCOL)
warning: SQLite database '/nix/var/nix/db/db.sqlite' is busy (SQLITE_PROTOCOL)
warning: SQLite database '/nix/var/nix/db/db.sqlite' is busy (SQLITE_PROTOCOL)
After:
$ inst/bin/nix-channel --update
unpacking channels...
created 1 symlinks in user environment
I've seen complaints that "sandbox" caused problems under WSL but I'm
having no problems. I think recent changes could have fixed the issue.
E.g.
$ nix-build '<nixpkgs>' -A hello --experimental-features no-url-literals
error: URL literals are disabled, at /nix/store/vsjamkzh15r3c779q2711az826hqgvzr-nixpkgs-20.03pre194957.bef773ed53f/nixpkgs/pkgs/top-level/all-packages.nix:1236:11
Helps with implementing https://github.com/NixOS/rfcs/pull/45.
Experimental features are now opt-in. There is currently one
experimental feature: "nix-command" (which enables the "nix"
command. This will allow us to merge experimental features more
quickly, without committing to supporting them indefinitely.
Typical usage:
$ nix build --experimental-features 'nix-command flakes' nixpkgs#hello
(cherry picked from commit 8e478c2341,
without the "flakes" feature)
Experimental features are now opt-in. There are currently two
experimental features: "nix-command" (which enables the "nix"
command), and "flakes" (which enables support for flakes). This will
allow us to merge experimental features more quickly, without
committing to supporting them indefinitely.
Typical usage:
$ nix build --experimental-features 'nix-command flakes' nixpkgs#hello
This currently fails because we're using POSIX file locks. So when the
garbage collector opens and closes its own temproots file, it causes
the lock to be released and then deleted by another GC instance.
Passing `--post-build-hook /foo/bar` to a nix-* command will cause
`/foo/bar` to be executed after each build with the following
environment variables set:
DRV_PATH=/nix/store/drv-that-has-been-built.drv
OUT_PATHS=/nix/store/...build /nix/store/...build-bin /nix/store/...build-dev
This can be useful in particular to upload all the builded artifacts to
the cache (including the ones that don't appear in the runtime closure
of the final derivation or are built because of IFD).
This new feature prints the stderr/stdout output to the `nix-build`
and `nix build` client, and the output is printed in a Nix 2
compatible format:
[nix]$ ./inst/bin/nix-build ./test.nix
these derivations will be built:
/nix/store/ishzj9ni17xq4hgrjvlyjkfvm00b0ch9-my-example-derivation.drv
building '/nix/store/ishzj9ni17xq4hgrjvlyjkfvm00b0ch9-my-example-derivation.drv'...
hello!
bye!
running post-build-hook '/home/grahamc/projects/github.com/NixOS/nix/post-hook.sh'...
post-build-hook: + sleep 1
post-build-hook: + echo 'Signing paths' /nix/store/qr213vjmibrqwnyp5fw678y7whbkqyny-my-example-derivation
post-build-hook: Signing paths /nix/store/qr213vjmibrqwnyp5fw678y7whbkqyny-my-example-derivation
post-build-hook: + sleep 1
post-build-hook: + echo 'Uploading paths' /nix/store/qr213vjmibrqwnyp5fw678y7whbkqyny-my-example-derivation
post-build-hook: Uploading paths /nix/store/qr213vjmibrqwnyp5fw678y7whbkqyny-my-example-derivation
post-build-hook: + sleep 1
post-build-hook: + printf 'very important stuff'
/nix/store/qr213vjmibrqwnyp5fw678y7whbkqyny-my-example-derivation
[nix-shell:~/projects/github.com/NixOS/nix]$ ./inst/bin/nix build -L -f ./test.nix
my-example-derivation> hello!
my-example-derivation> bye!
my-example-derivation (post)> + sleep 1
my-example-derivation (post)> + echo 'Signing paths' /nix/store/c263gzj2kb2609mz8wrbmh53l14wzmfs-my-example-derivation
my-example-derivation (post)> Signing paths /nix/store/c263gzj2kb2609mz8wrbmh53l14wzmfs-my-example-derivation
my-example-derivation (post)> + sleep 1
my-example-derivation (post)> + echo 'Uploading paths' /nix/store/c263gzj2kb2609mz8wrbmh53l14wzmfs-my-example-derivation
my-example-derivation (post)> Uploading paths /nix/store/c263gzj2kb2609mz8wrbmh53l14wzmfs-my-example-derivation
my-example-derivation (post)> + sleep 1
my-example-derivation (post)> + printf 'very important stuff'
[1 built, 0.0 MiB DL]
Co-authored-by: Graham Christensen <graham@grahamc.com>
Co-authored-by: Eelco Dolstra <edolstra@gmail.com>
When sandbox-fallback = true (the default), the Nix builder will fall
back to disabled sandbox mode when the kernel doesn’t allow users to
set it up. This prevents hard errors from occuring in tricky places,
especially the initial installer. To restore the previous behavior,
users can set:
sandbox-fallback = false
in their /etc/nix/nix.conf configuration.
This flag
* Disables substituters.
* Sets the tarball-ttl to infinity (ensuring e.g. that the flake
registry and any downloaded flakes are considered current).
* Disables retrying downloads and sets the connection timeout to the
minimum. (So it doesn't completely disable downloads at the moment.)
(cherry picked from commit 8ea842260b)
This flag
* Disables substituters.
* Sets the tarball-ttl to infinity (ensuring e.g. that the flake
registry and any downloaded flakes are considered current).
* Disables retrying downloads and sets the connection timeout to the
minimum. (So it doesn't completely disable downloads at the moment.)
Allow global config settings to be defined in multiple Config
classes. For example, this means that libutil can have settings and
evaluator settings can be moved out of libstore. The Config classes
are registered in a new GlobalConfig class to which config files
etc. are applied.
Relevant to https://github.com/NixOS/nix/issues/2009 in that it
removes the need for ad hoc handling of useCaseHack, which was the
underlying cause of that issue.
This allows specifying additional systems that a machine is able to
build for. This may apply on some armv7-capable aarch64 processors, or
on systems using qemu-user with binfmt-misc to support transparent
execution of foreign-arch programs.
This removes the previous hard-coded assumptions about which systems are
ABI-compatible with which other systems, and instead relies on the user
to specify any additional platforms that they have ensured compatibility
for and wish to build for locally.
NixOS should probably add i686-linux on x86_64-linux systems for this
setting by default.
The overhead of sandbox builds is a problem on NixOS (since building a
NixOS configuration involves a lot of small derivations) but not for
typical non-NixOS use cases. So outside of NixOS we can enable it.
Issue #179.
Previously, this would fail at startup for non-NixOS installs:
nix-env --help
The fix for this is to just use "nixManDir" as the value for MANPATH
when spawning "man".
To test this, I’m using the following:
$ nix-build release.nix -A build
$ MANPATH= ./result/bin/nix-env --help
Fixes#1627
In this mode, the following restrictions apply:
* The builtins currentTime, currentSystem and storePath throw an
error.
* $NIX_PATH and -I are ignored.
* fetchGit and fetchMercurial require a revision hash.
* fetchurl and fetchTarball require a sha256 attribute.
* No file system access is allowed outside of the paths returned by
fetch{Git,Mercurial,url,Tarball}. Thus 'nix build -f ./foo.nix' is
not allowed.
Thus, the evaluation result is completely reproducible from the
command line arguments. E.g.
nix build --pure-eval '(
let
nix = fetchGit { url = https://github.com/NixOS/nixpkgs.git; rev = "9c927de4b179a6dd210dd88d34bda8af4b575680"; };
nixpkgs = fetchGit { url = https://github.com/NixOS/nixpkgs.git; ref = "release-17.09"; rev = "66b4de79e3841530e6d9c6baf98702aa1f7124e4"; };
in (import (nix + "/release.nix") { inherit nix nixpkgs; }).build.x86_64-linux
)'
The goal is to enable completely reproducible and traceable
evaluation. For example, a NixOS configuration could be fully
described by a single Git commit hash. 'nixos-rebuild' would do
something like
nix build --pure-eval '(
(import (fetchGit { url = file:///my-nixos-config; rev = "..."; })).system
')
where the Git repository /my-nixos-config would use further fetchGit
calls or Git externals to fetch Nixpkgs and whatever other
dependencies it has. Either way, the commit hash would uniquely
identify the NixOS configuration and allow it to reproduced.
The name had become a misnomer since it's not only for substitution
from binary caches, but when adding/copying any
(non-content-addressed) path to a store.
You can now include files via the "builders" option, using the syntax
"@<filename>". Having only one option makes it easier to override
builders completely.
For backward compatibility, the default is "@/etc/nix/machines", or
"@<filename>" for each file name in NIX_REMOTE_SYSTEMS.
I needed this to test ACL/xattr removal in
canonicalisePathMetaData(). Might also be useful if you need to build
old Nixpkgs that doesn't have the required patches to remove
setuid/setgid creation.
Nix can now automatically run the garbage collector during builds or
while adding paths to the store. The option "min-free = <bytes>"
specifies that Nix should run the garbage collector whenever free
space in the Nix store drops below <bytes>. It will then delete
garbage until "max-free" bytes are available.
Garbage collection during builds is asynchronous; running builds are
not paused and new builds are not blocked. However, there also is a
synchronous GC run prior to the first build/substitution.
Currently, no old GC roots are deleted (as in "nix-collect-garbage
-d").
In particular, drop the "build-" and "gc-" prefixes which are
pointless. So now you can say
nix build --no-sandbox
instead of
nix build --no-build-use-sandbox
This allows builds to call setuid binaries. This was previously
possible until we started using seccomp. Turns out that seccomp by
default disallows processes from acquiring new privileges. Generally,
any use of setuid binaries (except those created by the builder
itself) is by definition impure, but some people were relying on this
ability for certain tests.
Example:
$ nix build '(with import <nixpkgs> {}; runCommand "foo" {} "/run/wrappers/bin/ping -c 1 8.8.8.8; exit 1")' --no-allow-new-privileges
builder for ‘/nix/store/j0nd8kv85hd6r4kxgnwzvr0k65ykf6fv-foo.drv’ failed with exit code 1; last 2 log lines:
cannot raise the capability into the Ambient set
: Operation not permitted
$ nix build '(with import <nixpkgs> {}; runCommand "foo" {} "/run/wrappers/bin/ping -c 1 8.8.8.8; exit 1")' --allow-new-privileges
builder for ‘/nix/store/j0nd8kv85hd6r4kxgnwzvr0k65ykf6fv-foo.drv’ failed with exit code 1; last 6 log lines:
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=46 time=15.2 ms
Fixes#1429.
This is useful for one-off situations where you want to specify a
builder on the command line instead of having to mess with
nix.machines. E.g.
$ nix-build -A hello --argstr system x86_64-darwin \
--option builders 'root@macstadium1 x86_64-darwin'
will perform the specified build on "macstadium1".
It also removes the need for a separate nix.machines file since you
can specify builders in nix.conf directly. (In fact nix.machines is
yet another hack that predates the general nix.conf configuration
file, IIRC.)
Note: this option is supported by the daemon for trusted users. The
fact that this allows trusted users to specify paths to SSH keys to
which they don't normally have access is maybe a bit too much trust...
