disasters involving `rm -rf' on bind mounts. Will try the
definitive fix (per-process mounts, apparently possible via the
CLONE_NEWNS flag in clone()) some other time.
need any info on substitutable paths, we just call the substituters
(such as download-using-manifests.pl) directly. This means that
it's no longer necessary for nix-pull to register substitutes or for
nix-channel to clear them, which makes those operations much faster
(NIX-95). Also, we don't have to worry about keeping nix-pull
manifests (in /nix/var/nix/manifests) and the database in sync with
each other.
The downside is that there is some overhead in calling an external
program to get the substitutes info. For instance, "nix-env -qas"
takes a bit longer.
Abolishing the substitutes table also makes the logic in
local-store.cc simpler, as we don't need to store info for invalid
paths. On the downside, you cannot do things like "nix-store -qR"
on a substitutable but invalid path (but nobody did that anyway).
* Never catch interrupts (the Interrupted exception).
seconds without producing output on stdout or stderr (NIX-65). This
timeout can be specified using the `--max-silent-time' option or the
`build-max-silent-time' configuration setting. The default is
infinity (0).
* Fix a tricky race condition: if we kill the build user before the
child has done its setuid() to the build user uid, then it won't be
killed, and we'll potentially lock up in pid.wait(). So also send a
conventional kill to the child.
root (or setuid root), then builds will be performed under one of
the users listed in the `build-users' configuration variables. This
is to make it impossible to influence build results externally,
allowing locally built derivations to be shared safely between
users (see ASE-2005 paper).
To do: only one builder should be active per build user.
to derivations in user environments. Nice for developers (since it
prevents build-time-only dependencies from being GC'ed, in
conjunction with `gc-keep-outputs'). Turned off by default.
permission to the Nix store or database. E.g., `nix-env -qa' will
work, but `nix-env -qas' won't (the latter needs DB access). The
option `--readonly-mode' forces this mode; otherwise, it's only
activated when the database cannot be opened.
Whenever Nix attempts to realise a derivation for which a closure is
already known, but this closure cannot be realised, fall back on
normalising the derivation.
The most common scenario in which this is useful is when we have
registered substitutes in order to perform binary distribution from,
say, a network repository. If the repository is down, the
realisation of the derivation will fail. When this option is
specified, Nix will build the derivation instead. Thus, binary
installation falls back on a source installation. This option is
not the default since it is generally not desirable for a transient
failure in obtaining the substitutes to lead to a full build from
source (with the related consumption of resources).
much as possible. (This is similar to GNU Make's `-k' flag.)
* Refactoring to implement this: previously we just bombed out when
a build failed, but now we have to clean up. In particular this
means that goals must be freed quickly --- they shouldn't hang
around until the worker exits. So the worker now maintains weak
pointers in order not to prevent garbage collection.
* Documented the `-k' and `-j' flags.
Eelco Dolstra