c505702265
though). In particular it's now much easier to register a GC root. Just place a symlink to whatever store path it is that you want to keep in /nix/var/nix/gcroots.
156 lines
4.4 KiB
C++
156 lines
4.4 KiB
C++
#include "globals.hh"
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#include "gc.hh"
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#include "build.hh"
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <unistd.h>
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void collectGarbage(const PathSet & roots, GCAction action,
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PathSet & result)
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{
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result.clear();
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/* !!! TODO: Acquire an exclusive lock on the gcroots directory.
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This prevents the set of live paths from increasing after this
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point. */
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/* Determine the live paths which is just the closure of the
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roots under the `references' relation. */
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PathSet livePaths;
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for (PathSet::const_iterator i = roots.begin(); i != roots.end(); ++i)
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computeFSClosure(canonPath(*i), livePaths);
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if (action == gcReturnLive) {
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result = livePaths;
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return;
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}
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/* !!! TODO: Try to acquire (without blocking) exclusive locks on
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the files in the `pending' directory. Delete all files for
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which we managed to acquire such a lock (since if we could get
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such a lock, that means that the process that owned the file
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has died). */
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/* !!! TODO: Acquire shared locks on all files in the pending
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directories. This prevents the set of pending paths from
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increasing while we are garbage-collecting. Read the set of
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pending paths from those files. */
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/* Read the Nix store directory to find all currently existing
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paths. */
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Strings storeNames = readDirectory(nixStore);
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for (Strings::iterator i = storeNames.begin(); i != storeNames.end(); ++i) {
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Path path = canonPath(nixStore + "/" + *i);
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if (livePaths.find(path) != livePaths.end()) {
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debug(format("live path `%1%'") % path);
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continue;
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}
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debug(format("dead path `%1%'") % path);
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result.insert(path);
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if (action == gcDeleteDead) {
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printMsg(lvlInfo, format("deleting `%1%'") % path);
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deleteFromStore(path);
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}
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}
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}
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#if 0
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void followLivePaths(Path nePath, PathSet & live)
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{
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/* Just to be sure, canonicalise the path. It is important to do
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this here and in findDeadPath() to ensure that a live path is
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not mistaken for a dead path due to some non-canonical
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representation. */
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nePath = canonPath(nePath);
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if (live.find(nePath) != live.end()) return;
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live.insert(nePath);
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startNest(nest, lvlDebug, format("following `%1%'") % nePath);
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assertStorePath(nePath);
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if (isValidPath(nePath)) {
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/* !!! should make sure that no substitutes are used */
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StoreExpr ne = storeExprFromPath(nePath);
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/* !!! painfully similar to requisitesWorker() */
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if (ne.type == StoreExpr::neClosure)
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for (ClosureElems::iterator i = ne.closure.elems.begin();
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i != ne.closure.elems.end(); ++i)
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{
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Path p = canonPath(i->first);
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if (live.find(p) == live.end()) {
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debug(format("found live `%1%'") % p);
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assertStorePath(p);
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live.insert(p);
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}
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}
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else if (ne.type == StoreExpr::neDerivation)
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for (PathSet::iterator i = ne.derivation.inputs.begin();
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i != ne.derivation.inputs.end(); ++i)
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followLivePaths(*i, live);
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else abort();
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}
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Path nfPath;
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if (querySuccessor(nePath, nfPath))
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followLivePaths(nfPath, live);
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}
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PathSet findLivePaths(const Paths & roots)
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{
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PathSet live;
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startNest(nest, lvlDebug, "finding live paths");
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for (Paths::const_iterator i = roots.begin(); i != roots.end(); ++i)
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followLivePaths(*i, live);
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return live;
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}
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PathSet findDeadPaths(const PathSet & live, time_t minAge)
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{
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PathSet dead;
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startNest(nest, lvlDebug, "finding dead paths");
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time_t now = time(0);
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Strings storeNames = readDirectory(nixStore);
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for (Strings::iterator i = storeNames.begin(); i != storeNames.end(); ++i) {
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Path p = canonPath(nixStore + "/" + *i);
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if (minAge > 0) {
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struct stat st;
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if (lstat(p.c_str(), &st) != 0)
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throw SysError(format("obtaining information about `%1%'") % p);
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if (st.st_atime + minAge >= now) continue;
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}
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if (live.find(p) == live.end()) {
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debug(format("dead path `%1%'") % p);
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dead.insert(p);
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} else
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debug(format("live path `%1%'") % p);
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}
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return dead;
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}
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#endif
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