Commit graph

309 commits

Author SHA1 Message Date
Eelco Dolstra 28bba8c44f Prevent config.h from being clobbered 2013-03-07 23:55:55 +01:00
Eelco Dolstra 5526a282b5 Security: Don't allow builders to change permissions on files they don't own
It turns out that in multi-user Nix, a builder may be able to do

  ln /etc/shadow $out/foo

Afterwards, canonicalisePathMetaData() will be applied to $out/foo,
causing /etc/shadow's mode to be set to 444 (readable by everybody but
writable by nobody).  That's obviously Very Bad.

Fortunately, this fails in NixOS's default configuration because
/nix/store is a bind mount, so "ln" will fail with "Invalid
cross-device link".  It also fails if hard-link restrictions are
enabled, so a workaround is:

  echo 1 > /proc/sys/fs/protected_hardlinks

The solution is to check that all files in $out are owned by the build
user.  This means that innocuous operations like "ln
${pkgs.foo}/some-file $out/" are now rejected, but that already failed
in chroot builds anyway.
2013-02-26 02:30:19 +01:00
Ludovic Courtès 5ea138dc4b Enable chroot support on old glibc versions. 2013-02-19 10:19:11 +01:00
Eelco Dolstra 536c85ea49 Store build logs in /nix/var/log/nix/drvs/<XX>
...where <XX> is the first two characters of the derivation.
Otherwise /nix/var/log/nix/drvs may become so large that we run into
all sorts of weird filesystem limits/inefficiences.  For instance,
ext3/ext4 filesystems will barf with "ext4_dx_add_entry:1551:
Directory index full!" once you hit a few million files.
2013-01-17 15:47:26 +01:00
Eelco Dolstra def5160b61 Clear any immutable bits in the Nix store
Doing this once makes subsequent operations like garbage collecting
more efficient since we don't have to call makeMutable() first.
2013-01-03 12:59:23 +01:00
Eelco Dolstra 299141ecbd If a substitute closure is incomplete, build dependencies, then retry the substituter
Issue #77.
2013-01-02 12:38:28 +01:00
Eelco Dolstra 1b3a78a459 Automatically fall back if the references of a substitute are not substitutable
Fixes #77.
2013-01-02 12:00:26 +01:00
Eelco Dolstra b7629778ef Allow mounting a path in a different location in the chroot
Fixes #24.
2012-12-29 23:04:02 +01:00
Eelco Dolstra fbf0b2fa45 Kill the build hook rather than shutting it down cleanly
Waiting for the hook to shut down cleanly sometimes seems to lead to
hangs.
2012-12-19 11:47:42 +01:00
Eelco Dolstra 228ea7c2f9 Revert brain fart
This reverts commit cc511fd65b.
2012-12-18 20:43:47 +01:00
Eelco Dolstra cc511fd65b Check for potential infinite select() loops when building 2012-12-18 18:50:05 +01:00
Eelco Dolstra 8d8d47abd2 Only substitute wanted outputs of a derivation
If a derivation has multiple outputs, then we only want to download
those outputs that are actuallty needed.  So if we do "nix-build -A
openssl.man", then only the "man" output should be downloaded.
Likewise if another package depends on ${openssl.man}.

The tricky part is that different derivations can depend on different
outputs of a given derivation, so we may need to restart the
corresponding derivation goal if that happens.
2012-11-26 17:15:09 +01:00
Eelco Dolstra 46a369ad95 Make "nix-build -A <derivation>.<output>" do the right thing
For example, given a derivation with outputs "out", "man" and "bin":

  $ nix-build -A pkg

produces ./result pointing to the "out" output;

  $ nix-build -A pkg.man

produces ./result-man pointing to the "man" output;

  $ nix-build -A pkg.all

produces ./result, ./result-man and ./result-bin;

  $ nix-build -A pkg.all -A pkg2

produces ./result, ./result-man, ./result-bin and ./result-2.
2012-11-26 15:39:10 +01:00
Eelco Dolstra f794465ca8 Disable use of vfork()
vfork() is just too weird.  For instance, in this build:

  http://hydra.nixos.org/build/3330487

the value fromHook.writeSide becomes corrupted in the parent, even
though the child only reads from it.  At -O0 the problem goes away.
Probably the child is overriding some spilled temporary variable.

If I get bored I may implement using posix_spawn() instead.
2012-11-15 19:35:18 +01:00
Eelco Dolstra 8541d27fce Don't use std::cerr in a few places
Slightly scared of using std::cerr in a vforked process...
2012-11-15 15:01:02 +01:00
Eelco Dolstra ea89df2b76 Use vfork() instead of fork() if available
Hopefully this reduces the chance of hitting ‘unable to fork: Cannot
allocate memory’ errors.  vfork() is used for everything except
starting builders.
2012-11-09 18:00:33 +01:00
Eelco Dolstra 198dbe7fa1 Remove some redundant close() calls
They are unnecessary because we set the close-on-exec flag.
2012-11-09 16:58:51 +01:00
Eelco Dolstra 10dcee99ed Remove the quickExit function 2012-11-09 16:42:10 +01:00
Eelco Dolstra 4c34d384e6 If hashes do not match, print them in base-32 for SHA-1/SHA-256
Fixes #57.
2012-10-23 18:05:50 +02:00
Eelco Dolstra e345182055 Shorten the names of temporary build directories 2012-10-11 14:03:06 -04:00
Eelco Dolstra 2bbc4a214e nix-env: Support ‘--repair’ flag 2012-10-03 15:35:42 -04:00
Eelco Dolstra a807edfae8 Handle repairing paths that are in build-chroot-dirs 2012-10-03 11:20:16 -04:00
Eelco Dolstra a3f205b249 When repairing a derivation, check and repair the entire output closure
If we find a corrupted path in the output closure, we rebuild the
derivation that produced that particular path.
2012-10-03 10:38:09 -04:00
Eelco Dolstra 2001895f3d Add a --repair flag to ‘nix-store -r’ to repair derivation outputs
With this flag, if any valid derivation output is missing or corrupt,
it will be recreated by using a substitute if available, or by
rebuilding the derivation.  The latter may use hash rewriting if
chroots are not available.
2012-10-02 17:13:46 -04:00
Eelco Dolstra 9958bd6992 Add operation ‘nix-store --repair-path’
This operation allows fixing corrupted or accidentally deleted store
paths by redownloading them using substituters, if available.

Since the corrupted path cannot be replaced atomically, there is a
very small time window (one system call) during which neither the old
(corrupted) nor the new (repaired) contents are available.  So
repairing should be used with some care on critical packages like
Glibc.
2012-10-02 14:08:59 -04:00
Eelco Dolstra e666e1156f Handle octal escapes in /proc/self/mountinfo 2012-09-28 21:39:30 -04:00
Eelco Dolstra f406288cc7 Print a more descriptive error message if setting up the build environment fails 2012-09-28 21:37:02 -04:00
Eelco Dolstra b9c2b4d5b4 Remove setting of the immutable bit
Using the immutable bit is problematic, especially in conjunction with
store optimisation.  For instance, if the garbage collector deletes a
file, it has to clear its immutable bit, but if the file has
additional hard links, we can't set the bit afterwards because we
don't know the remaining paths.

So now that we support having the entire Nix store as a read-only
mount, we may as well drop the immutable bit.  Unfortunately, we have
to keep the code to clear the immutable bit for backwards
compatibility.
2012-09-19 16:17:54 -04:00
Eelco Dolstra 76e88871b2 Templatise tokenizeString() 2012-09-19 15:43:23 -04:00
Eelco Dolstra 00092b2d35 Keep build directory if not all expected outputs were produced
Fixes issue #123 in Nixpkgs.
2012-09-18 10:11:42 -04:00
Eelco Dolstra e56f71edaf In startBuilder(), only print the new paths we're building 2012-09-13 10:06:24 -04:00
Eelco Dolstra 479e9172b3 Build hook: Pass the timeout to the remote builder
Note that this will only work if the client has a very recent Nix
version (post 15e1b2c223), otherwise the
--option flag will just be ignored.

Fixes #50.
2012-09-12 12:18:14 -04:00
Eelco Dolstra 5e2ffd0b8a Fix "non-zero padding" error
Probably it's not a good idea to pass a temporary object to
StringSource.
2012-09-11 19:09:01 -04:00
Eelco Dolstra 8cf672091e Support building a derivation if some outputs are already valid (non-chroot case)
This uses scary hash rewriting.

Fixes #21.
2012-09-11 18:39:22 -04:00
Eelco Dolstra 9dbda2b3fe Remove debug line 2012-09-11 17:05:35 -04:00
Eelco Dolstra a2785b7391 Support building a derivation if some outputs are already valid
This handles the chroot and build hook cases, which are easy.
Supporting the non-chroot-build case will require more work (hash
rewriting!).

Issue #21.
2012-09-11 16:59:59 -04:00
Eelco Dolstra cfd968dd94 Fix stupid type error in calling std::max 2012-08-27 14:17:13 -04:00
Eelco Dolstra e94806d030 Merge branch 'master' into no-manifests 2012-08-27 11:09:07 -04:00
Eelco Dolstra d950cfe70b Check if MS_PRIVATE is defined
http://hydra.nixos.org/build/2955671
2012-08-20 15:55:49 -04:00
Eelco Dolstra 56e30e161c In the chroot, make all mounted filesystems private
This is required on systemd, which mounts filesystems as "shared"
subtrees.  Changes to shared trees in a private mount namespace are
propagated to the outside world, which is bad.
2012-08-20 15:27:30 -04:00
Eelco Dolstra f0eab0636b Don't bind-mount /proc since we mount our own 2012-08-20 15:27:00 -04:00
Eelco Dolstra 862c4c5ec5 Fix 1755 permission on temporary directories left behind by ‘-K’ 2012-08-19 16:32:42 -04:00
Eelco Dolstra 01d56c1eec Drop the block count in the garbage collector 2012-08-01 22:34:46 -04:00
Eelco Dolstra 97421eb5ec Refactor settings processing
Put all Nix configuration flags in a Settings object.
2012-07-30 19:55:41 -04:00
Eelco Dolstra d059bf48e4 Pass configuration settings to the substituters
Previously substituters could read nix.conf themselves, but this
didn't take --option flags into account.
2012-07-30 16:09:54 -04:00
Eelco Dolstra 73acb8b836 Let build.cc verify the expected hash of a substituter's output
Since SubstitutionGoal::finished() in build.cc computes the hash
anyway, we can prevent the inefficiency of computing the hash twice by
letting the substituter tell Nix about the expected hash, which can
then verify it.
2012-07-27 12:16:02 -04:00
Eelco Dolstra fbf59d95f6 Remove more tabs 2012-07-27 10:56:33 -04:00
Eelco Dolstra b4ea83249b Remove trailing whitespace / tabs 2012-07-27 09:59:18 -04:00
Eelco Dolstra 8c79100839 Merge branch 'master' into no-manifests 2012-07-26 15:14:33 -04:00
Eelco Dolstra 3a4623afbb Set permissions on temporary build directories to 0700
Fixes #39.
2012-07-26 15:04:40 -04:00
Eelco Dolstra 6193105710 Automatically optimise the Nix store when a new path is added
Auto-optimisation is enabled by default.  It can be turned off by
setting auto-optimise-store to false in nix.conf.
2012-07-23 17:14:15 -04:00
Eelco Dolstra fe241ece29 Merge branch 'master' into no-manifests 2012-07-18 10:47:59 -04:00
Eelco Dolstra 3a9fdf2747 Return an exit code of 100 for cached failed builds
Exit code 100 should be returned for all permanent failures.  This
includes cached failures.

Fixes #34.
2012-07-17 15:55:30 -04:00
Eelco Dolstra 6c01fb4d68 Update Nix 1.1 release notes 2012-07-17 10:06:20 -04:00
Eelco Dolstra 53b24f3518 Allow disabling log compression 2012-07-17 09:40:12 -04:00
Eelco Dolstra 425cc612ad build.cc: Don't use hasSubstitute()
Instead make a single call to querySubstitutablePathInfo() per
derivation output.  This is faster and prevents having to implement
the "have" function in the binary cache substituter.
2012-07-08 18:39:24 -04:00
Eelco Dolstra 11800e6198 download-from-binary-cache: parallelise fetching of NAR info files
Getting substitute information using the binary cache substituter has
non-trivial latency overhead.  A package or NixOS system configuration
can have hundreds of dependencies, and in the worst case (when the
local info cache is empty) we have to do a separate HTTP request for
each of these.  If the ping time to the server is t, getting N info
files will take tN seconds; e.g., with a ping time of 0.1s to
nixos.org, sequentially downloading 1000 info files (a typical NixOS
config) will take at least 100 seconds.

To fix this problem, the binary cache substituter can now perform
requests in parallel.  This required changing the substituter
interface to support a function querySubstitutablePathInfos() that
queries multiple paths at the same time, and rewriting queryMissing()
to take advantage of parallelism.  (Due to local caching,
parallelising queryMissing() is sufficient for most use cases, since
it's almost always called before building a derivation and thus fills
the local info cache.)

For example, parallelism speeds up querying all 1056 paths in a
particular NixOS system configuration from 116s to 2.6s.  It works so
well because the eccentricity of the top-level derivation in the
dependency graph is only 9.  So we only need 10 round-trips (when
using an unlimited number of parallel connections) to get everything.

Currently we do a maximum of 150 parallel connections to the server.
Thus it's important that the binary cache server (e.g. nixos.org) has
a high connection limit.  Alternatively we could use HTTP pipelining,
but WWW::Curl doesn't support it and libcurl has a hard-coded limit of
5 requests per pipeline.
2012-07-06 19:08:20 -04:00
Eelco Dolstra 1aba0bf0fa nix-store -r: do substitutions in parallel
I.e. when multiple non-derivation arguments are passed to ‘nix-store
-r’ to be substituted, do them in parallel.
2012-06-27 16:58:15 -04:00
Eelco Dolstra 42f5a2fc29 Mount an empty /dev/shm tmpfs in the chroot
This ensures that whatever the builder writes in /dev/shm is
automatically cleaned up.
2012-06-27 09:52:27 -04:00
Eelco Dolstra 3ee208516f Check the return code of the clone() call 2012-06-27 09:52:06 -04:00
Eelco Dolstra 1db38ae81b When using chroots, use a private PID namespace
In a private PID namespace, processes have PIDs that are separate from
the rest of the system.  The initial child gets PID 1.  Processes in
the chroot cannot see processes outside of the chroot.  This improves
isolation between builds.  However, processes on the outside can see
processes in the chroot and send signals to them (if they have
appropriate rights).

Since the builder gets PID 1, it serves as the reaper for zombies in
the chroot.  This might turn out to be a problem.  In that case we'll
need to have a small PID 1 process that sits in a loop calling wait().
2012-06-25 15:45:16 -04:00
Eelco Dolstra 5489086456 Use a private UTS namespace to provide a deterministic host/domain name to builders
In chroot builds, set the host name to "localhost" and the domain name
to "(none)" (the latter being the kernel's default).  This improves
determinism a bit further.

P.S. I have to idea what UTS stands for.
2012-06-25 14:12:17 -04:00
Eelco Dolstra 723a68c826 Improve error message 2012-06-23 00:57:14 -04:00
Eelco Dolstra 7ffa523fd1 In chroot builds, use a private SysV IPC namespace
This improves isolation a bit further, and it's just one extra flag in
the unshare() call.

P.S. It would be very cool to use CLONE_NEWPID (to put the builder in
a private PID namespace) as well, but that's slightly more risky since
having a builder start as PID 1 may cause problems.
2012-06-23 00:51:40 -04:00
Eelco Dolstra df716c98d2 In chroot builds, use a private network namespace
On Linux it's possible to run a process in its own network namespace,
meaning that it gets its own set of network interfaces, disjunct from
the rest of the system.  We use this to completely remove network
access to chroot builds, except that they get a private loopback
interface.  This means that:

- Builders cannot connect to the outside network or to other processes
  on the same machine, except processes within the same build.

- Vice versa, other processes cannot connect to processes in a chroot
  build, and open ports/connections do not show up in "netstat".

- If two concurrent builders try to listen on the same port (e.g. as
  part of a test), they no longer conflict with each other.

This was inspired by the "PrivateNetwork" flag in systemd.
2012-06-23 00:28:35 -04:00
Eelco Dolstra f5398d374b Compress build logs on the fly using bzip2 2012-05-30 10:12:29 -04:00
Eelco Dolstra 2c26985835 Add option ‘build-keep-log’ to enable/disable writing of build logs
Fixes #26.
2012-05-29 16:42:05 -04:00
Eelco Dolstra db5b86ef13 * Add an option ‘build-use-substitutes’, which can be set to ‘false’
to disable use of substitutes; i.e., force building from source.
  Fixes Nix/221.
2012-04-30 19:15:34 -04:00
Eelco Dolstra 46cdc6ad51 Handle EPERM when creating a hard link for the chroot
There is a race condition when doing parallel builds with chroots and
the immutable bit enabled.  One process may call makeImmutable()
before the other has called link(), in which case link() will fail
with EPERM.  We could retry or wrap the operation in a lock, but since
this condition is rare and I'm lazy, we just use the existing copy
fallback.

Fixes #9.
2012-04-30 10:58:04 -04:00
Eelco Dolstra 31e34fcf93 Close almost all file descriptors in the builder
This regression was accidentally introduced in
35355fc1fc.
2012-04-15 00:20:32 +02:00
Eelco Dolstra f2467eb6a0 On Linux, pretend we're building on Linux 2.6
Setting the UNAME26 personality causes "uname" to return "2.6.x",
regardless of the kernel version.  This improves determinism in
a few misbehaved packages.
2012-04-05 13:03:19 +02:00
Eelco Dolstra 35355fc1fc Set the close-on-exec flag on file descriptors 2012-03-05 20:29:00 +01:00
Eelco Dolstra 7b22bec252 Don't leak a file descriptor in commonChildInit() 2012-03-05 20:28:09 +01:00
Eelco Dolstra 1c94524458 Fix an uninitialised variable
The variable ‘useChroot’ was not initialised properly.  This caused
random failures if using the build hook.  Seen on Mac OS X 10.7 with Clang.
Thanks to KolibriFX for finding this :-)
2012-03-01 16:06:49 +01:00
Eelco Dolstra 6fe13e6aba Fix chroots builds
Chroots are initialised by hard-linking inputs from the Nix store to
the chroot.  This doesn't work if the input has its immutable bit set,
because it's forbidden to create hard links to immutable files.  So
temporarily clear the immutable bit when creating and destroying the
chroot.

Note that making regular files in the Nix store immutable isn't very
reliable, since the bit can easily become cleared: for instance, if we
run the garbage collector after running ‘nix-store --optimise’.  So
maybe we should only make directories immutable.
2012-02-18 01:23:52 +01:00
Eelco Dolstra d5a5a83ad4 Use data() instead of c_str() where appropriate 2012-02-09 18:27:45 +01:00
Eelco Dolstra b1004f40f7 * Reject a build if there is a cycle among the outputs. This is
necessary because existing code assumes that the references graph is
  acyclic.
2011-12-30 14:47:14 +00:00
Eelco Dolstra 8c42a8c8ff * Make sure that lock files are cleaned up properly when building
through the build hook.
2011-12-25 16:38:37 +00:00
Eelco Dolstra b1eb8f4249 * Get rid of some superfluous error messages if a substituter fails.
* Say "fetch" instead of "substitute".
2011-11-29 13:00:41 +00:00
Rob Vermaas 4e1ea17052 nix: add /etc/hosts with localhost entry to chroot builds. 2011-11-21 15:19:51 +00:00
Eelco Dolstra 93227ff65c * Eliminate all uses of the global variable ‘store’ from libstore.
This should also fix:

    nix-instantiate: ./../boost/shared_ptr.hpp:254: T* boost::shared_ptr<T>::operator->() const [with T = nix::StoreAPI]: Assertion `px != 0' failed.

  which was caused by hashDerivationModulo() calling the ‘store’
  object (during store upgrades) before openStore() assigned it.
2011-08-31 21:11:50 +00:00
Eelco Dolstra b2027f70d9 * Fix a huuuuge security hole in the Nix daemon. It didn't check that
derivations added to the store by clients have "correct" output
  paths (meaning that the output paths are computed by hashing the
  derivation according to a certain algorithm).  This means that a
  malicious user could craft a special .drv file to build *any*
  desired path in the store with any desired contents (so long as the
  path doesn't already exist).  Then the attacker just needs to wait
  for a victim to come along and install the compromised path.

  For instance, if Alice (the attacker) knows that the latest Firefox
  derivation in Nixpkgs produces the path

    /nix/store/1a5nyfd4ajxbyy97r1fslhgrv70gj8a7-firefox-5.0.1

  then (provided this path doesn't already exist) she can craft a .drv
  file that creates that path (i.e., has it as one of its outputs),
  add it to the store using "nix-store --add", and build it with
  "nix-store -r".  So the fake .drv could write a Trojan to the
  Firefox path.  Then, if user Bob (the victim) comes along and does

    $ nix-env -i firefox
    $ firefox

  he executes the Trojan injected by Alice.

  The fix is to have the Nix daemon verify that derivation outputs are
  correct (in addValidPath()).  This required some refactoring to move
  the hash computation code to libstore.
2011-07-20 18:10:47 +00:00
Ludovic Courtès 5c9e9f732d Add support for the build-timeout' and --timeout' options. 2011-06-30 15:19:13 +00:00
Eelco Dolstra d787285af9 * nix-instantiate: return exit status 100 to denote a permanent build
failure.  The build hook can use this to distinguish between
  transient and permanent failures on the remote side.
2010-12-13 16:53:23 +00:00
Eelco Dolstra d7ca6f44eb * Update some comments. 2010-12-13 13:19:46 +00:00
Eelco Dolstra a3883cbd28 * Store the size of a store path in the database (to be precise, the
size of the NAR serialisation of the path, i.e., `nix-store --dump
  PATH').  This is useful for Hydra.
2010-11-16 17:11:46 +00:00
Eelco Dolstra bf0dde9597 * Always print hook output on stderr, even if --no-build-output is
set.
* In the build hook, print a trace message to allow Hydra to pick up
  the name of the remote machine used for the build.
2010-08-31 12:36:24 +00:00
Eelco Dolstra 80e722278c * When using the build hook, distinguish between the stderr of the
hook script proper, and the stdout/stderr of the builder.  Only the
  latter should be saved in /nix/var/log/nix/drvs.
* Allow the verbosity to be set through an option.
* Added a flag --quiet to lower the verbosity level.
2010-08-30 14:53:03 +00:00
Eelco Dolstra 766f708418 * Experimental feature: allow a derivation to tell the build hook that
it requires a certain feature on the build machine, e.g.

    requiredSystemFeatures = [ "kvm" ];

  We need this in Hydra to make sure that builds that require KVM
  support are forwarded to machines that have KVM support.  Probably
  this should also be enforced for local builds.
2010-08-27 13:18:13 +00:00
Eelco Dolstra e437b08250 * Made the build hook mechanism more efficient. Rather than starting
the hook every time we want to ask whether we can run a remote build
  (which can be very often), we now reuse a hook process for answering
  those queries until it accepts a build.  So if there are N
  derivations to be built, at most N hooks will be started.
2010-08-25 20:44:28 +00:00
Eelco Dolstra f58f51f380 * Handle the unlikely case where a derivation has no dependencies at
all.
2010-08-24 11:45:44 +00:00
Eelco Dolstra 587dc8aa00 * Sync with the trunk. 2010-08-04 17:48:29 +00:00
Eelco Dolstra 7f893b7a43 * Allow derivations to hint that they should not be built remotely
using the build hook mechanism, by setting the derivation attribute
  "preferLocalBuild" to true.  This has a few use cases:

  - The user environment builder.  Since it just creates a bunch of
    symlinks without much computation, there is no reason to do it
    remotely.  In fact, doing it remotely requires the entire closure
    of the user environment to be copied to the remote machine, which
    is extremely wasteful.

  - `fetchurl'.  Performing the download on a remote machine and then
    copying it to the local machine involves twice as much network
    traffic as performing the download locally, and doesn't save any
    CPU cycles on the local machine.
2010-08-04 12:13:58 +00:00
Peter Simons a17071fef1 Include <cstring> to ensure that strcpy(), strlen(), and memset() are declared.
An "using namespace std" was added locally in those functions that refer to
names from <cstring>. That is not pretty, but it's a very portable solution,
because strcpy() and friends will be found in both the 'std' and in the global
namespace.
2010-06-24 17:51:04 +00:00
Peter Simons 8b7f8b56f1 Added support for passing an (impure) NIX_BUILD_CORES variable to build expressions.
This patch adds the configuration file variable "build-cores" and the
command line argument "--cores". These settings specify the number of
CPU cores to utilize for parallel building within a job, i.e. by passing
an appropriate "-j" flag to GNU Make. The default value is 1, which
means that parallel building is *disabled*. If the number of build cores
is specified as 0 (synonymously: "guess" or "auto"), then the actual
value is supposed to be auto-detected by builders at run-time, i.e by
calling the nproc(1) utility from coreutils.

The environment variable $NIX_BUILD_CORES is available to builders, but
the contents of that variable does *not* influence the hash that goes
into the $out store path, i.e. the number of build cores to be utilized
can be changed at will without requiring any re-builds.
2010-06-23 14:34:08 +00:00
Eelco Dolstra bf87cc44b4 * Sync with the trunk. 2010-06-21 07:55:38 +00:00
Eelco Dolstra 89865da76d * Turn build errors during evaluation into EvalErrors. 2010-06-01 11:19:32 +00:00
Eelco Dolstra a443c7573b * Hack to allow derivations to disable chroot builds by setting the
attribute "__noChroot = true" (requested by Rob).
2010-06-01 10:01:14 +00:00
Eelco Dolstra e020d80e4e * Sync with the trunk. 2010-03-11 15:45:05 +00:00
Ludovic Courtès 05e15049a5 Show the build user's group in /etc/group in chroots.
* src/libstore/build.cc (nix::DerivationGoal::startBuilder): Create
  /etc/group showing the build user's group.
2010-03-11 14:47:04 +00:00