evaluator. This was important because the NixOS expressions started
to hit 2 MB default stack size on Linux.
GCC is really dumb about stack space: it just adds up all the local
variables and temporaries of every scope into one huge stack frame.
This is really bad for deeply recursive functions. For instance,
every `throw Error(format("error message"))' causes a format object
of a few hundred bytes to be allocated on the stack. As a result,
every recursive call to evalExpr2() consumed 4680 bytes. By
splitting evalExpr2() and by moving the exception-throwing code out
of the main functions, evalExpr2() now only consumes 40 bytes.
Similar for evalExpr().
which paths specified on the command line are invalid (i.e., don't
barf when encountering an invalid path, just print it). This is
useful for build-remote.pl to figure out which paths need to be
copied to a remote machine. (Currently we use rsync, but that's
rather inefficient.)
--export' into the Nix store, and optionally check the cryptographic
signatures against /nix/etc/nix/signing-key.pub. (TODO: verify
against a set of public keys.)
path. This is like `nix-store --dump', only it also dumps the
meta-information of the store path (references, deriver). Will add
a `--sign' flag later to add a cryptographic signature, which we
will use for exchanging store paths between build farm machines in a
secure manner.
attribute) about installed packages in user environments. Thus, an
operation like `nix-env -q --description' shows useful information
not only on available packages but also on installed packages.
* nix-env now passes the entire manifest as an argument to the Nix
expression of the user environment builder (not just a list of
paths), so that in particular the user environment builder has
access to the meta attributes.
* New operation `--set-flag' in nix-env to change meta info of
installed packages. This will be useful to pass per-package
policies to the user environment builder (e.g., how to resolve
collision or whether to disable a package (NIX-80)) or upgrade
policies in nix-env (e.g., that a package should be "masked", that
is, left untouched by upgrade actions). Example:
$ nix-env --set-flag enabled false ghc-6.4
computing the store path (NIX-77). This is an important security
property in multi-user Nix stores.
Note that this changes the store paths of derivations (since the
derivation aterms are added using addTextToStore), but not most
outputs (unless they use builtins.toFile).
* `sub' to subtract two numbers.
* `stringLength' to get the length of a string.
* `substring' to get a substring of a string. These should be enough
to allow most string operations to be expressed.
programs, so if a builder uses TMPDIR, then it will fail when
executed through nix-setuid-helper. In fact Glibc clears a whole
bunch of variables (see sysdeps/generic/unsecvars.h in the Glibc
sources), but only TMPDIR should matter in practice. As a
workaround, we reinitialise TMPDIR from NIX_BUILD_TOP.
important to get garbage collection to work if there is any
inconsistency in the database (because the referrer table is used to
determine whether it is safe to delete a path).
* `nix-store --verify': show some progress.
* nix-unpack-closure: extract the top-level paths from the closure and
print them on stdout. This allows them to be installed, e.g.,
"nix-env -i $(nix-unpack-closure)". (NIX-64)
<derivation outPath=... drvPath=...> attrs </derivation>. Only emit
the attributes of any specific derivation only. This prevents
exponententially large XML output due to the absense of sharing.
from a source directory. All files for which a predicate function
returns true are copied to the store. Typical example is to leave
out the .svn directory:
stdenv.mkDerivation {
...
src = builtins.filterSource
(path: baseNameOf (toString path) != ".svn")
./source-dir;
# as opposed to
# src = ./source-dir;
}
This is important because the .svn directory influences the hash in
a rather unpredictable and variable way.
single derivation specified by the argument. This is useful when we
want to have a profile for a single derivation, such as a server
configuration. Then we can just say (e.g.)
$ nix-env -p /.../server-profile -f server.nix --set -A server
We can't do queries or upgrades on such a profile, but we can do
rollbacks. The advantage over -i is that we don't have to worry
about other packages having been installed in the profile
previously; --set gets rid of them.
matters when running as root, since then we don't use the setuid
helper (which already used lchown()).
* Also check for an obscure security problem on platforms that don't
have lchown. Then we can't change the ownership of symlinks, which
doesn't matter *except* when the containing directory is writable by
the owner (which is the case with the top-level Nix store directory).
