forked from lix-project/lix
dcc37c236c
immediately add the result as a permanent GC root. This is the only
way to prevent a race with the garbage collector. For instance, the
old style
ln -s $(nix-store -r $(nix-instantiate foo.nix)) \
/nix/var/nix/gcroots/result
has two time windows in which the garbage collector can interfere
(by GC'ing the derivation and the output, respectively). On the
other hand,
nix-store --add-root /nix/var/nix/gcroots/result -r \
$(nix-instantiate --add-root /nix/var/nix/gcroots/drv \
foo.nix)
is safe.
* nix-build: use `--add-root' to prevent GC races.
34 lines
1.1 KiB
C++
34 lines
1.1 KiB
C++
#ifndef __GC_H
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#define __GC_H
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#include "util.hh"
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/* Garbage collector operation. */
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typedef enum { gcReturnLive, gcReturnDead, gcDeleteDead } GCAction;
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/* If `action' is set to `soReturnLive', return the set of paths
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reachable from (i.e. in the closure of) the specified roots. If
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`action' is `soReturnDead', return the set of paths not reachable
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from the roots. If `action' is `soDeleteDead', actually delete the
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latter set. */
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void collectGarbage(const PathSet & roots, GCAction action,
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PathSet & result);
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/* Register a temporary GC root. This root will automatically
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disappear when this process exits. WARNING: this function should
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not be called inside a BDB transaction, otherwise we can
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deadlock. */
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void addTempRoot(const Path & path);
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/* Remove the temporary roots file for this process. Any temporary
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root becomes garbage after this point unless it has been registered
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as a (permanent) root. */
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void removeTempRoots();
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/* Register a permanent GC root. */
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Path addPermRoot(const Path & storePath, const Path & gcRoot);
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#endif /* !__GC_H */
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