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.
112 lines
3.5 KiB
C++
112 lines
3.5 KiB
C++
#ifndef __STORE_H
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#define __STORE_H
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#include <string>
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#include "hash.hh"
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#include "db.hh"
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using namespace std;
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/* A substitute is a program invocation that constructs some store
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path (typically by fetching it from somewhere, e.g., from the
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network). */
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struct Substitute
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{
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/* Program to be executed to create the store path. Must be in
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the output path of `storeExpr'. */
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Path program;
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/* Extra arguments to be passed to the program (the first argument
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is the store path to be substituted). */
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Strings args;
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bool operator == (const Substitute & sub);
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};
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typedef list<Substitute> Substitutes;
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/* Open the database environment. */
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void openDB();
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/* Create the required database tables. */
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void initDB();
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/* Get a transaction object. */
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void createStoreTransaction(Transaction & txn);
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/* Copy a path recursively. */
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void copyPath(const Path & src, const Path & dst);
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/* Register a substitute. */
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void registerSubstitute(const Transaction & txn,
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const Path & srcPath, const Substitute & sub);
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/* Return the substitutes for the given path. */
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Substitutes querySubstitutes(const Transaction & txn, const Path & srcPath);
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/* Deregister all substitutes. */
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void clearSubstitutes();
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/* Register the validity of a path, i.e., that `path' exists, that the
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paths referenced by it exists, and in the case of an output path of
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a derivation, that it has been produced by a succesful execution of
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the derivation (or something equivalent). Also register the hash
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of the file system contents of the path. The hash must be a
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SHA-256 hash. */
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void registerValidPath(const Transaction & txn,
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const Path & path, const Hash & hash, const PathSet & references);
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/* Throw an exception if `path' is not directly in the Nix store. */
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void assertStorePath(const Path & path);
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bool isStorePath(const Path & path);
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/* "Fix", or canonicalise, the meta-data of the files in a store path
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after it has been built. In particular:
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- the last modification date on each file is set to 0 (i.e.,
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00:00:00 1/1/1970 UTC)
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- the permissions are set of 444 or 555 (i.e., read-only with or
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without execute permission; setuid bits etc. are cleared)
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- the owner and group are set to the Nix user and group, if we're
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in a setuid Nix installation. */
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void canonicalisePathMetaData(const Path & path);
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/* Checks whether a path is valid. */
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bool isValidPath(const Path & path);
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/* Sets the set of outgoing FS references for a store path. */
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void setReferences(const Transaction & txn, const Path & storePath,
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const PathSet & references);
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/* Queries the set of outgoing FS references for a store path. The
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result is not cleared. */
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void queryReferences(const Path & storePath, PathSet & references);
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/* Queries the set of incoming FS references for a store path. The
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result is not cleared. */
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void queryReferers(const Path & storePath, PathSet & referers);
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/* Constructs a unique store path name. */
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Path makeStorePath(const string & type,
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const Hash & hash, const string & suffix);
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/* Copy the contents of a path to the store and register the validity
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the resulting path. The resulting path is returned. */
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Path addToStore(const Path & srcPath);
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/* Like addToStore, but the contents written to the output path is a
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regular file containing the given string. */
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Path addTextToStore(const string & suffix, const string & s,
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const PathSet & references);
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/* Delete a value from the nixStore directory. */
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void deleteFromStore(const Path & path);
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void verifyStore();
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#endif /* !__STORE_H */
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