This is useful for testing commands in isolation.
For example,
$ nix run nixpkgs.geeqie -i -k DISPLAY -k XAUTHORITY -c geeqie
runs geeqie in an empty environment, except for $DISPLAY and
$XAUTHORITY.
E.g.
nix run nixpkgs.hello -c hello --greeting Hallo
Note that unlike "nix-shell --command", no quoting of arguments is
necessary.
"-c" (short for "--command") cannot be combined with "--" because they
both consume all remaining arguments. But since installables shouldn't
start with a dash, this is unlikely to cause problems.
Running "nix run" with a diverted store, e.g.
$ nix run --store local?root=/tmp/nix nixpkgs.hello
stopped working when Nix became multithreaded, because
unshare(CLONE_NEWUSER) doesn't work in multithreaded processes. The
obvious solution is to terminate all other threads first, but 1) there
is no way to terminate Boehm GC marker threads; and 2) it appears that
the kernel has a race where unshare(CLONE_NEWUSER) will still fail for
some indeterminate amount of time after joining other threads.
So instead, "nix run" will now exec() a single-threaded helper ("nix
__run_in_chroot") that performs the actual unshare()/chroot()/exec().
Now that we use threads in lots of places, it's possible for
TunnelLogger::log() to be called asynchronously from other threads
than the main loop. So we need to ensure that STDERR_NEXT messages
don't clobber other messages.
Besides being unused, this function has a bug that it will incorrectly
decode the path component Ubuntu\04016.04.2\040LTS\040amd64 as
"Ubuntu.04.2 LTS amd64" instead of "Ubuntu 16.04.2 LTS amd64".
This adds an argument "rev" specififying the Git commit hash. The
existing argument "rev" is renamed to "ref". The default value for
"ref" is "master". When specifying a hash, it's necessary to specify a
ref since we're not cloning the entire repository but only fetching a
specific ref.
Example usage:
builtins.fetchgit {
url = https://github.com/NixOS/nixpkgs.git;
ref = "release-16.03";
rev = "c1c0484041ab6f9c6858c8ade80a8477c9ae4442";
};
The package list is now cached in
~/.cache/nix/package-search.json. This gives a substantial speedup to
"nix search" queries. For example (on an SSD):
First run: (no package search cache, cold page cache)
$ time nix search blender
Attribute name: nixpkgs.blender
Package name: blender
Version: 2.78c
Description: 3D Creation/Animation/Publishing System
real 0m6.516s
Second run: (package search cache populated)
$ time nix search blender
Attribute name: nixpkgs.blender
Package name: blender
Version: 2.78c
Description: 3D Creation/Animation/Publishing System
real 0m0.143s
In particular, don't use base-64, which we don't support. (We do have
base-32 redirects for hysterical reasons.)
Also, add a test for the hashed mirror feature.
This doesn't work in read-only mode, ensuring that operations like
nix path-info --store https://cache.nixos.org -S nixpkgs.hello
(asking for the closure size of nixpkgs.hello in cache.nixos.org) work
when nixpkgs.hello doesn't exist in the local store.
On second though this was annoying. E.g. "nix log nixpkgs.hello" would
build/download Hello first, even though the log can be fetched
directly from the binary cache.
May need to revisit this.
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.
Functions like copyClosure() had 3 bool arguments, which creates a
severe risk of mixing up arguments.
Also, implement copyClosure() using copyPaths().
Cygwin sqlite3 is patched to call SetDllDirectory("/usr/bin") on init, which
affects the current process and is inherited by child processes. It causes
DLLs to be loaded from /usr/bin/ before $PATH, which breaks all sorts of
things. A typical failures would be header/lib version mismatches (e.g.
openssl when running checkPhase on openssh). We'll just set it back to the
default value.
Note that this is a problem with the cygwin version of sqlite3 (currently
3.18.0). nixpkgs doesn't have the problematic patch.
There's no reason to restrict this to Error exceptions. This shouldn't
matter to #1407 since the repl doesn't catch non-Error exceptions
anyway, but you never know...
Recently aws-sdk-cpp quietly switched to using S3 virtual host URIs
(https://github.com/aws/aws-sdk-cpp/commit/69d9c53882), i.e. it sends
requests to http://<bucket>.<region>.s3.amazonaws.com rather than
http://<region>.s3.amazonaws.com/<bucket>. However this interacts
badly with curl connection reuse. For example, if we do the following:
1) Check whether a bucket exists using GetBucketLocation.
2) If it doesn't, create it using CreateBucket.
3) Do operations on the bucket.
then 3) will fail for a minute or so with a NoSuchBucket exception,
presumably because the server being hit is a fallback for cases when
buckets don't exist.
Disabling the use of virtual hosts ensures that 3) succeeds
immediately. (I don't know what S3's consistency guarantees are for
bucket creation, but in practice buckets appear to be available
immediately.)
Newer versions of aws-sdk-cpp call CalculateDelayBeforeNextRetry()
even for non-retriable errors (like NoSuchKey) whih causes log spam in
hydra-queue-runner.
Sandboxes cannot be nested, so if Nix's build runs inside a sandbox,
it cannot use a sandbox itself. I don't see a clean way to detect
whether we're in a sandbox, so use a test-specific hack.
https://github.com/NixOS/nix/issues/1413
Jörg Thalheim