Commit graph

179 commits

Author SHA1 Message Date
Eelco Dolstra 0111ba98ea Handle hard links to other files in the output 2013-02-27 17:18:41 +01:00
Eelco Dolstra b008674e46 Refactoring: Split off the non-recursive canonicalisePathMetaData()
Also, change the file mode before changing the owner.  This prevents a
slight time window in which a setuid binary would be setuid root.
2013-02-27 16:42:19 +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
Eelco Dolstra 5e9c3da412 Only warn about SQLite being busy once
No need to get annoying.
2013-01-23 16:45:10 +01:00
Eelco Dolstra b424d29d1b Open the database after removing immutable bits 2013-01-03 13:29:17 +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 772778c0ec On SQLITE_BUSY, wait a random amount of time
If all contending processes wait a fixed amount of time (100 ms),
there is a good probability that they'll just collide again.
2012-12-11 11:49:42 +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 4c9e3fa641 Remove a Darwin hack that should no longer be needed 2012-11-09 16:35:42 +01:00
Eelco Dolstra 91ef4d9a81 Remove unnecessary call to closeMostFDs()
We have close-on-exec on all FDs now, and there is no security risk in
passing open FDs to substituters anyway.
2012-11-09 14:43:47 +01:00
Shea Levy d0fc615af6 canonicalizePathMetaData: Fall-back to utimes if lutimes fails due to ENOSYS 2012-11-06 11:29:59 +01:00
Eelco Dolstra 904f50412c nix-store --verify: Continue on errors 2012-10-04 10:20:23 -04:00
Eelco Dolstra 7586095504 Remove bin2c 2012-10-03 16:59:28 -04:00
Eelco Dolstra 0a7084567f Add a ‘--repair’ flag to nix-instantiate
This allows repairing corrupted derivations and other source files.
2012-10-03 15:09:18 -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 8e3a7bd712 nix-store --verify: Add an option ‘--repair’ to repair all missing/corrupt paths
Also, return a non-zero exit code if errors remain after
verifying/repairing.
2012-10-02 15:12:56 -04:00
Eelco Dolstra d534f137f0 Make the store writable before creating /nix/store/.links 2012-09-25 16:30:08 -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 b9124a5c33 Support having /nix/store as a read-only bind mount
It turns out that the immutable bit doesn't work all that well.  A
better way is to make the entire Nix store a read-only bind mount,
i.e. by doing

  $ mount --bind /nix/store /nix/store
  $ mount -o remount,ro,bind /nix/store

(This would typically done in an early boot script, before anything
from /nix/store is used.)

Since Nix needs to be able to write to the Nix store, it now detects
if /nix/store is a read-only bind mount and then makes it writable in
a private mount namespace.
2012-09-19 15:45:29 -04:00
Eelco Dolstra 76e88871b2 Templatise tokenizeString() 2012-09-19 15:43:23 -04:00
Eelco Dolstra e6e495649c Vacuum the SQLite DB after running the garbage collector 2012-09-13 14:33:41 -04:00
Eelco Dolstra c770a2422a Report substituter errors to clients of the Nix daemon 2012-08-01 11:19:24 -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 f9613da180 Remove unused variables 2012-07-30 15:43:37 -04:00
Eelco Dolstra 6183cf2f19 Fix whitespace 2012-07-30 15:42:18 -04:00
Eelco Dolstra 50395b71a9 Fix the substituter tests 2012-07-26 17:36:07 -04:00
Eelco Dolstra 8c79100839 Merge branch 'master' into no-manifests 2012-07-26 15:14:33 -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 6852289c46 Use lutimes() if available to canonicalise the timestamp of symlinks
Also use utimes() instead of utime() if lutimes() is not available.
2012-07-23 16:52:25 -04:00
Eelco Dolstra fe241ece29 Merge branch 'master' into no-manifests 2012-07-18 10:47:59 -04:00
Eelco Dolstra ccc52adfb2 Add function queryPathFromHashPart()
To implement binary caches efficiently, Hydra needs to be able to map
the hash part of a store path (e.g. "gbg...zr7") to the full store
path (e.g. "/nix/store/gbg...kzr7-subversion-1.7.5").  (The binary
cache mechanism uses hash parts as a key for looking up store paths to
ensure privacy.)  However, doing a search in the Nix store for
/nix/store/<hash>* is expensive since it requires reading the entire
directory.  queryPathFromHashPart() prevents this by doing a cheap
database lookup.
2012-07-17 18:55:39 -04:00
Eelco Dolstra 09a6321aeb Replace hasSubstitutes() with querySubstitutablePaths()
querySubstitutablePaths() takes a set of paths, so this greatly
reduces daemon <-> client latency.
2012-07-11 17:52:18 -04:00
Eelco Dolstra 58ef4d9a95 Add a function queryValidPaths()
queryValidPaths() combines multiple calls to isValidPath() in one.
This matters when using the Nix daemon because it reduces latency.
For instance, on "nix-env -qas \*" it reduces execution time from 5.7s
to 4.7s (which is indistinguishable from the non-daemon case).
2012-07-11 11:08:47 -04:00
Eelco Dolstra 667d5f1936 Rename queryValidPaths() to queryAllValidPaths() 2012-07-11 10:49:04 -04:00
Eelco Dolstra eb3036da87 Implement querySubstitutablePathInfos() in the daemon
Also removed querySubstitutablePathInfo().
2012-07-11 10:43:24 -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 4bc4da331a Reserve some disk space for the garbage collector
We can't open a SQLite database if the disk is full.  Since this
prevents the garbage collector from running when it's most needed, we
reserve some dummy space that we can free just before doing a garbage
collection.  This actually revives some old code from the Berkeley DB
days.

Fixes #27.
2012-05-29 22:59:12 -04:00
Eelco Dolstra 6387830c3b Merge pull request #2 from viric/master
Again, adding the sync option
2012-04-23 03:29:03 -07:00
Eelco Dolstra 117670be57 Make the garbage collector more concurrent
Make the garbage collector more concurrent by deleting valid paths
outside the region where we're holding the global GC lock.  This
should greatly reduce the time during which new builds are blocked,
since the deletion accounts for the vast majority of the time spent in
the GC.

To ensure that this is safe, the valid paths are invalidated and
renamed to some arbitrary path while we're holding the lock.  This
ensures that we when we finally delete the path, it's not a (newly)
valid or locked path.
2012-03-26 20:43:33 +02:00
Lluís Batlle i Rossell 85799bf89e Fixing the default of sync-before-registering
Setting 'false' as default, as suggested by Eelco.

I also added a comment about the setting in the code.
2012-03-22 20:05:54 +01:00
Lluís Batlle i Rossell 25de80e2b6 Adding a nix option to sync before registering a path, for non-ext*
filesystems.
2012-03-22 19:57:42 +01:00
Eelco Dolstra 19d9762ad5 nix-store --clear-failed-paths: Clear derivation outputs
If the argument to ‘nix-store --clear-failed-paths’ is a derivation,
then clear the failed state of its outputs.
2012-03-20 18:23:26 +01:00
Eelco Dolstra 2b4964f319 Restore progress indication during nix-copy-closure 2012-03-05 18:13:44 +01:00
Eelco Dolstra 8afd28a922 Remove dependency on sqlite3_table_column_metadata
Not all SQLite builds have the function sqlite3_table_column_metadata.
We were only using it in a schema upgrade check for compatibility with
databases that were probably never seen in the wild.  So remove it.
2012-03-01 16:06:49 +01:00
Eelco Dolstra bd013b6f98 On Linux, make the Nix store really read-only by using the immutable bit
I was bitten one time too many by Python modifying the Nix store by
creating *.pyc files when run as root.  On Linux, we can prevent this
by setting the immutable bit on files and directories (as in ‘chattr
+i’).  This isn't supported by all filesystems, so it's not an error
if setting the bit fails.  The immutable bit is cleared by the garbage
collector before deleting a path.  The only tricky aspect is in
optimiseStore(), since it's forbidden to create hard links to an
immutable file.  Thus optimiseStore() temporarily clears the immutable
bit before creating the link.
2012-02-15 01:31:56 +01:00
Eelco Dolstra 5e57047d87 Fix a broken guard around utime()
Because of an outdated check for a timestamp of 0, we were calling
utime() even when it wasn't necessary.
2012-02-15 01:00:30 +01:00