Commit | Line | Data |
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36457566 LC |
1 | #include "globals.hh" |
2 | #include "misc.hh" | |
3 | #include "local-store.hh" | |
4 | ||
5 | #include <functional> | |
6 | #include <queue> | |
7 | #include <algorithm> | |
8 | ||
9 | #include <sys/types.h> | |
10 | #include <sys/stat.h> | |
11 | #include <errno.h> | |
12 | #include <fcntl.h> | |
13 | #include <unistd.h> | |
732c96f1 | 14 | #include <climits> |
36457566 LC |
15 | |
16 | ||
17 | namespace nix { | |
18 | ||
19 | ||
20 | static string gcLockName = "gc.lock"; | |
21 | static string tempRootsDir = "temproots"; | |
22 | static string gcRootsDir = "gcroots"; | |
23 | ||
24 | ||
8327e733 | 25 | /* Acquire the global GC lock. This is used to prevent new build |
36457566 LC |
26 | processes from starting after the temporary root files have been |
27 | read. To be precise: when they try to create a new temporary root | |
28 | file, they will block until the garbage collector has finished / | |
29 | yielded the GC lock. */ | |
30 | int LocalStore::openGCLock(LockType lockType) | |
31 | { | |
32 | Path fnGCLock = (format("%1%/%2%") | |
33 | % settings.nixStateDir % gcLockName).str(); | |
34 | ||
35 | debug(format("acquiring global GC lock `%1%'") % fnGCLock); | |
36 | ||
37 | AutoCloseFD fdGCLock = open(fnGCLock.c_str(), O_RDWR | O_CREAT, 0600); | |
38 | if (fdGCLock == -1) | |
39 | throw SysError(format("opening global GC lock `%1%'") % fnGCLock); | |
40 | closeOnExec(fdGCLock); | |
41 | ||
42 | if (!lockFile(fdGCLock, lockType, false)) { | |
43 | printMsg(lvlError, format("waiting for the big garbage collector lock...")); | |
44 | lockFile(fdGCLock, lockType, true); | |
45 | } | |
46 | ||
47 | /* !!! Restrict read permission on the GC root. Otherwise any | |
48 | process that can open the file for reading can DoS the | |
49 | collector. */ | |
50 | ||
51 | return fdGCLock.borrow(); | |
52 | } | |
53 | ||
54 | ||
55 | static void makeSymlink(const Path & link, const Path & target) | |
56 | { | |
57 | /* Create directories up to `gcRoot'. */ | |
58 | createDirs(dirOf(link)); | |
59 | ||
60 | /* Create the new symlink. */ | |
61 | Path tempLink = (format("%1%.tmp-%2%-%3%") | |
62 | % link % getpid() % rand()).str(); | |
63 | createSymlink(target, tempLink); | |
64 | ||
65 | /* Atomically replace the old one. */ | |
66 | if (rename(tempLink.c_str(), link.c_str()) == -1) | |
67 | throw SysError(format("cannot rename `%1%' to `%2%'") | |
68 | % tempLink % link); | |
69 | } | |
70 | ||
71 | ||
72 | void LocalStore::syncWithGC() | |
73 | { | |
74 | AutoCloseFD fdGCLock = openGCLock(ltRead); | |
75 | } | |
76 | ||
77 | ||
78 | void LocalStore::addIndirectRoot(const Path & path) | |
79 | { | |
80 | string hash = printHash32(hashString(htSHA1, path)); | |
81 | Path realRoot = canonPath((format("%1%/%2%/auto/%3%") | |
82 | % settings.nixStateDir % gcRootsDir % hash).str()); | |
83 | makeSymlink(realRoot, path); | |
84 | } | |
85 | ||
86 | ||
87 | Path addPermRoot(StoreAPI & store, const Path & _storePath, | |
88 | const Path & _gcRoot, bool indirect, bool allowOutsideRootsDir) | |
89 | { | |
90 | Path storePath(canonPath(_storePath)); | |
91 | Path gcRoot(canonPath(_gcRoot)); | |
92 | assertStorePath(storePath); | |
93 | ||
94 | if (isInStore(gcRoot)) | |
95 | throw Error(format( | |
8327e733 | 96 | "creating a garbage collector root (%1%) in the store is forbidden " |
36457566 LC |
97 | "(are you running nix-build inside the store?)") % gcRoot); |
98 | ||
99 | if (indirect) { | |
54c260e6 | 100 | /* Don't clobber the link if it already exists and doesn't |
8327e733 | 101 | point to the store. */ |
36457566 LC |
102 | if (pathExists(gcRoot) && (!isLink(gcRoot) || !isInStore(readLink(gcRoot)))) |
103 | throw Error(format("cannot create symlink `%1%'; already exists") % gcRoot); | |
104 | makeSymlink(gcRoot, storePath); | |
105 | store.addIndirectRoot(gcRoot); | |
106 | } | |
107 | ||
108 | else { | |
109 | if (!allowOutsideRootsDir) { | |
110 | Path rootsDir = canonPath((format("%1%/%2%") % settings.nixStateDir % gcRootsDir).str()); | |
111 | ||
112 | if (string(gcRoot, 0, rootsDir.size() + 1) != rootsDir + "/") | |
113 | throw Error(format( | |
114 | "path `%1%' is not a valid garbage collector root; " | |
115 | "it's not in the directory `%2%'") | |
116 | % gcRoot % rootsDir); | |
117 | } | |
118 | ||
2bb04905 LC |
119 | if (baseNameOf(gcRoot) == baseNameOf(storePath)) |
120 | writeFile(gcRoot, ""); | |
121 | else | |
122 | makeSymlink(gcRoot, storePath); | |
36457566 LC |
123 | } |
124 | ||
125 | /* Check that the root can be found by the garbage collector. | |
126 | !!! This can be very slow on machines that have many roots. | |
127 | Instead of reading all the roots, it would be more efficient to | |
128 | check if the root is in a directory in or linked from the | |
129 | gcroots directory. */ | |
130 | if (settings.checkRootReachability) { | |
131 | Roots roots = store.findRoots(); | |
132 | if (roots.find(gcRoot) == roots.end()) | |
133 | printMsg(lvlError, | |
134 | format( | |
135 | "warning: `%1%' is not in a directory where the garbage collector looks for roots; " | |
136 | "therefore, `%2%' might be removed by the garbage collector") | |
137 | % gcRoot % storePath); | |
138 | } | |
139 | ||
140 | /* Grab the global GC root, causing us to block while a GC is in | |
141 | progress. This prevents the set of permanent roots from | |
142 | increasing while a GC is in progress. */ | |
143 | store.syncWithGC(); | |
144 | ||
145 | return gcRoot; | |
146 | } | |
147 | ||
148 | ||
36457566 LC |
149 | void LocalStore::addTempRoot(const Path & path) |
150 | { | |
151 | /* Create the temporary roots file for this process. */ | |
152 | if (fdTempRoots == -1) { | |
153 | ||
154 | while (1) { | |
155 | Path dir = (format("%1%/%2%") % settings.nixStateDir % tempRootsDir).str(); | |
156 | createDirs(dir); | |
157 | ||
158 | fnTempRoots = (format("%1%/%2%") | |
159 | % dir % getpid()).str(); | |
160 | ||
161 | AutoCloseFD fdGCLock = openGCLock(ltRead); | |
162 | ||
163 | if (pathExists(fnTempRoots)) | |
164 | /* It *must* be stale, since there can be no two | |
165 | processes with the same pid. */ | |
166 | unlink(fnTempRoots.c_str()); | |
167 | ||
168 | fdTempRoots = openLockFile(fnTempRoots, true); | |
169 | ||
170 | fdGCLock.close(); | |
171 | ||
172 | debug(format("acquiring read lock on `%1%'") % fnTempRoots); | |
173 | lockFile(fdTempRoots, ltRead, true); | |
174 | ||
175 | /* Check whether the garbage collector didn't get in our | |
176 | way. */ | |
177 | struct stat st; | |
178 | if (fstat(fdTempRoots, &st) == -1) | |
179 | throw SysError(format("statting `%1%'") % fnTempRoots); | |
180 | if (st.st_size == 0) break; | |
181 | ||
182 | /* The garbage collector deleted this file before we could | |
183 | get a lock. (It won't delete the file after we get a | |
184 | lock.) Try again. */ | |
185 | } | |
186 | ||
187 | } | |
188 | ||
189 | /* Upgrade the lock to a write lock. This will cause us to block | |
190 | if the garbage collector is holding our lock. */ | |
191 | debug(format("acquiring write lock on `%1%'") % fnTempRoots); | |
192 | lockFile(fdTempRoots, ltWrite, true); | |
193 | ||
194 | string s = path + '\0'; | |
54c260e6 | 195 | writeFull(fdTempRoots, s); |
36457566 LC |
196 | |
197 | /* Downgrade to a read lock. */ | |
198 | debug(format("downgrading to read lock on `%1%'") % fnTempRoots); | |
199 | lockFile(fdTempRoots, ltRead, true); | |
200 | } | |
201 | ||
202 | ||
36457566 LC |
203 | typedef std::shared_ptr<AutoCloseFD> FDPtr; |
204 | typedef list<FDPtr> FDs; | |
205 | ||
206 | ||
207 | static void readTempRoots(PathSet & tempRoots, FDs & fds) | |
208 | { | |
209 | /* Read the `temproots' directory for per-process temporary root | |
210 | files. */ | |
2bb04905 | 211 | DirEntries tempRootFiles = readDirectory( |
36457566 LC |
212 | (format("%1%/%2%") % settings.nixStateDir % tempRootsDir).str()); |
213 | ||
2bb04905 LC |
214 | for (auto & i : tempRootFiles) { |
215 | Path path = (format("%1%/%2%/%3%") % settings.nixStateDir % tempRootsDir % i.name).str(); | |
36457566 LC |
216 | |
217 | debug(format("reading temporary root file `%1%'") % path); | |
218 | FDPtr fd(new AutoCloseFD(open(path.c_str(), O_RDWR, 0666))); | |
219 | if (*fd == -1) { | |
220 | /* It's okay if the file has disappeared. */ | |
221 | if (errno == ENOENT) continue; | |
222 | throw SysError(format("opening temporary roots file `%1%'") % path); | |
223 | } | |
224 | ||
225 | /* This should work, but doesn't, for some reason. */ | |
226 | //FDPtr fd(new AutoCloseFD(openLockFile(path, false))); | |
227 | //if (*fd == -1) continue; | |
228 | ||
eec920ba LC |
229 | /* Try to acquire a write lock without blocking. This can |
230 | only succeed if the owning process has died. In that case | |
231 | we don't care about its temporary roots. */ | |
232 | if (lockFile(*fd, ltWrite, false)) { | |
36457566 LC |
233 | printMsg(lvlError, format("removing stale temporary roots file `%1%'") % path); |
234 | unlink(path.c_str()); | |
54c260e6 | 235 | writeFull(*fd, "d"); |
36457566 LC |
236 | continue; |
237 | } | |
238 | ||
239 | /* Acquire a read lock. This will prevent the owning process | |
240 | from upgrading to a write lock, therefore it will block in | |
241 | addTempRoot(). */ | |
242 | debug(format("waiting for read lock on `%1%'") % path); | |
243 | lockFile(*fd, ltRead, true); | |
244 | ||
245 | /* Read the entire file. */ | |
246 | string contents = readFile(*fd); | |
247 | ||
248 | /* Extract the roots. */ | |
249 | string::size_type pos = 0, end; | |
250 | ||
251 | while ((end = contents.find((char) 0, pos)) != string::npos) { | |
252 | Path root(contents, pos, end - pos); | |
253 | debug(format("got temporary root `%1%'") % root); | |
254 | assertStorePath(root); | |
255 | tempRoots.insert(root); | |
256 | pos = end + 1; | |
257 | } | |
258 | ||
259 | fds.push_back(fd); /* keep open */ | |
260 | } | |
261 | } | |
262 | ||
263 | ||
264 | static void foundRoot(StoreAPI & store, | |
265 | const Path & path, const Path & target, Roots & roots) | |
266 | { | |
267 | Path storePath = toStorePath(target); | |
268 | if (store.isValidPath(storePath)) | |
269 | roots[path] = storePath; | |
270 | else | |
271 | printMsg(lvlInfo, format("skipping invalid root from `%1%' to `%2%'") % path % storePath); | |
272 | } | |
273 | ||
274 | ||
2bb04905 | 275 | static void findRoots(StoreAPI & store, const Path & path, unsigned char type, Roots & roots) |
36457566 LC |
276 | { |
277 | try { | |
278 | ||
2bb04905 LC |
279 | if (type == DT_UNKNOWN) |
280 | type = getFileType(path); | |
36457566 | 281 | |
2bb04905 LC |
282 | if (type == DT_DIR) { |
283 | for (auto & i : readDirectory(path)) | |
284 | findRoots(store, path + "/" + i.name, i.type, roots); | |
36457566 LC |
285 | } |
286 | ||
2bb04905 | 287 | else if (type == DT_LNK) { |
36457566 LC |
288 | Path target = readLink(path); |
289 | if (isInStore(target)) | |
290 | foundRoot(store, path, target, roots); | |
291 | ||
292 | /* Handle indirect roots. */ | |
293 | else { | |
294 | target = absPath(target, dirOf(path)); | |
295 | if (!pathExists(target)) { | |
296 | if (isInDir(path, settings.nixStateDir + "/" + gcRootsDir + "/auto")) { | |
297 | printMsg(lvlInfo, format("removing stale link from `%1%' to `%2%'") % path % target); | |
298 | unlink(path.c_str()); | |
299 | } | |
300 | } else { | |
301 | struct stat st2 = lstat(target); | |
302 | if (!S_ISLNK(st2.st_mode)) return; | |
303 | Path target2 = readLink(target); | |
304 | if (isInStore(target2)) foundRoot(store, target, target2, roots); | |
305 | } | |
306 | } | |
307 | } | |
308 | ||
2bb04905 LC |
309 | else if (type == DT_REG) { |
310 | Path storePath = settings.nixStore + "/" + baseNameOf(path); | |
311 | if (store.isValidPath(storePath)) | |
312 | roots[path] = storePath; | |
313 | } | |
314 | ||
36457566 LC |
315 | } |
316 | ||
317 | catch (SysError & e) { | |
318 | /* We only ignore permanent failures. */ | |
319 | if (e.errNo == EACCES || e.errNo == ENOENT || e.errNo == ENOTDIR) | |
320 | printMsg(lvlInfo, format("cannot read potential root `%1%'") % path); | |
321 | else | |
322 | throw; | |
323 | } | |
324 | } | |
325 | ||
326 | ||
327 | Roots LocalStore::findRoots() | |
328 | { | |
329 | Roots roots; | |
330 | ||
331 | /* Process direct roots in {gcroots,manifests,profiles}. */ | |
2bb04905 LC |
332 | nix::findRoots(*this, settings.nixStateDir + "/" + gcRootsDir, DT_UNKNOWN, roots); |
333 | if (pathExists(settings.nixStateDir + "/manifests")) | |
334 | nix::findRoots(*this, settings.nixStateDir + "/manifests", DT_UNKNOWN, roots); | |
335 | nix::findRoots(*this, settings.nixStateDir + "/profiles", DT_UNKNOWN, roots); | |
36457566 LC |
336 | |
337 | return roots; | |
338 | } | |
339 | ||
340 | ||
341 | static void addAdditionalRoots(StoreAPI & store, PathSet & roots) | |
342 | { | |
2e3e5d21 LC |
343 | debug(format("executing `%1% gc --list-busy' to find additional roots") |
344 | % settings.guixProgram); | |
36457566 | 345 | |
2e3e5d21 LC |
346 | const Strings args = { "gc", "--list-busy" }; |
347 | string result = runProgram(settings.guixProgram, false, args); | |
36457566 LC |
348 | |
349 | StringSet paths = tokenizeString<StringSet>(result, "\n"); | |
350 | ||
351 | foreach (StringSet::iterator, i, paths) { | |
352 | if (isInStore(*i)) { | |
353 | Path path = toStorePath(*i); | |
354 | if (roots.find(path) == roots.end() && store.isValidPath(path)) { | |
355 | debug(format("got additional root `%1%'") % path); | |
356 | roots.insert(path); | |
357 | } | |
358 | } | |
359 | } | |
360 | } | |
361 | ||
362 | ||
363 | struct GCLimitReached { }; | |
364 | ||
365 | ||
366 | struct LocalStore::GCState | |
367 | { | |
368 | GCOptions options; | |
369 | GCResults & results; | |
370 | PathSet roots; | |
371 | PathSet tempRoots; | |
372 | PathSet dead; | |
373 | PathSet alive; | |
374 | bool gcKeepOutputs; | |
375 | bool gcKeepDerivations; | |
376 | unsigned long long bytesInvalidated; | |
322eeb87 | 377 | bool moveToTrash = true; |
36457566 LC |
378 | Path trashDir; |
379 | bool shouldDelete; | |
380 | GCState(GCResults & results_) : results(results_), bytesInvalidated(0) { } | |
381 | }; | |
382 | ||
383 | ||
384 | bool LocalStore::isActiveTempFile(const GCState & state, | |
385 | const Path & path, const string & suffix) | |
386 | { | |
387 | return hasSuffix(path, suffix) | |
388 | && state.tempRoots.find(string(path, 0, path.size() - suffix.size())) != state.tempRoots.end(); | |
389 | } | |
390 | ||
391 | ||
392 | void LocalStore::deleteGarbage(GCState & state, const Path & path) | |
393 | { | |
394 | unsigned long long bytesFreed; | |
7033c769 LC |
395 | |
396 | /* When deduplication is on, store items always have at least two links: | |
397 | the one at PATH, and one in /gnu/store/.links. In that case, increase | |
398 | bytesFreed when PATH has two or fewer links. */ | |
399 | size_t linkThreshold = | |
400 | (settings.autoOptimiseStore && isStorePath(path)) ? 2 : 1; | |
401 | ||
402 | deletePath(path, bytesFreed, linkThreshold); | |
36457566 LC |
403 | state.results.bytesFreed += bytesFreed; |
404 | } | |
405 | ||
406 | ||
407 | void LocalStore::deletePathRecursive(GCState & state, const Path & path) | |
408 | { | |
409 | checkInterrupt(); | |
410 | ||
411 | unsigned long long size = 0; | |
412 | ||
413 | if (isValidPath(path)) { | |
414 | PathSet referrers; | |
415 | queryReferrers(path, referrers); | |
416 | foreach (PathSet::iterator, i, referrers) | |
417 | if (*i != path) deletePathRecursive(state, *i); | |
418 | size = queryPathInfo(path).narSize; | |
419 | invalidatePathChecked(path); | |
420 | } | |
421 | ||
422 | struct stat st; | |
423 | if (lstat(path.c_str(), &st)) { | |
424 | if (errno == ENOENT) return; | |
425 | throw SysError(format("getting status of %1%") % path); | |
426 | } | |
427 | ||
732c96f1 | 428 | if (state.options.maxFreed != ULLONG_MAX) { |
be0fb348 LC |
429 | auto freed = state.results.bytesFreed + state.bytesInvalidated; |
430 | double fraction = ((double) freed) / (double) state.options.maxFreed; | |
732c96f1 LC |
431 | unsigned int percentage = (fraction > 1. ? 1. : fraction) * 100.; |
432 | printMsg(lvlInfo, format("[%1%%%] deleting '%2%'") % percentage % path); | |
433 | } else { | |
be0fb348 LC |
434 | auto freed = state.results.bytesFreed + state.bytesInvalidated; |
435 | freed /= 1024ULL * 1024ULL; | |
436 | printMsg(lvlInfo, format("[%1% MiB] deleting '%2%'") % freed % path); | |
732c96f1 | 437 | } |
36457566 LC |
438 | |
439 | state.results.paths.insert(path); | |
440 | ||
441 | /* If the path is not a regular file or symlink, move it to the | |
442 | trash directory. The move is to ensure that later (when we're | |
443 | not holding the global GC lock) we can delete the path without | |
444 | being afraid that the path has become alive again. Otherwise | |
445 | delete it right away. */ | |
322eeb87 | 446 | if (state.moveToTrash && S_ISDIR(st.st_mode)) { |
36457566 LC |
447 | // Estimate the amount freed using the narSize field. FIXME: |
448 | // if the path was not valid, need to determine the actual | |
449 | // size. | |
322eeb87 LC |
450 | try { |
451 | if (chmod(path.c_str(), st.st_mode | S_IWUSR) == -1) | |
452 | throw SysError(format("making `%1%' writable") % path); | |
453 | Path tmp = state.trashDir + "/" + baseNameOf(path); | |
454 | if (rename(path.c_str(), tmp.c_str())) | |
455 | throw SysError(format("unable to rename `%1%' to `%2%'") % path % tmp); | |
456 | state.bytesInvalidated += size; | |
457 | } catch (SysError & e) { | |
d445c30e CM |
458 | /* In a Docker container, rename(2) returns EXDEV when the source |
459 | and destination are not both on the "top layer". See: | |
460 | https://bugs.gnu.org/41607 */ | |
461 | if (e.errNo == ENOSPC || e.errNo == EXDEV) { | |
322eeb87 LC |
462 | printMsg(lvlInfo, format("note: can't create move `%1%': %2%") % path % e.msg()); |
463 | deleteGarbage(state, path); | |
464 | } | |
465 | } | |
36457566 LC |
466 | } else |
467 | deleteGarbage(state, path); | |
468 | ||
469 | if (state.results.bytesFreed + state.bytesInvalidated > state.options.maxFreed) { | |
470 | printMsg(lvlInfo, format("deleted or invalidated more than %1% bytes; stopping") % state.options.maxFreed); | |
471 | throw GCLimitReached(); | |
472 | } | |
473 | } | |
474 | ||
475 | ||
476 | bool LocalStore::canReachRoot(GCState & state, PathSet & visited, const Path & path) | |
477 | { | |
478 | if (visited.find(path) != visited.end()) return false; | |
479 | ||
480 | if (state.alive.find(path) != state.alive.end()) { | |
481 | return true; | |
482 | } | |
483 | ||
484 | if (state.dead.find(path) != state.dead.end()) { | |
485 | return false; | |
486 | } | |
487 | ||
488 | if (state.roots.find(path) != state.roots.end()) { | |
489 | printMsg(lvlDebug, format("cannot delete `%1%' because it's a root") % path); | |
490 | state.alive.insert(path); | |
491 | return true; | |
492 | } | |
493 | ||
494 | visited.insert(path); | |
495 | ||
496 | if (!isValidPath(path)) return false; | |
497 | ||
498 | PathSet incoming; | |
499 | ||
500 | /* Don't delete this path if any of its referrers are alive. */ | |
501 | queryReferrers(path, incoming); | |
502 | ||
503 | /* If gc-keep-derivations is set and this is a derivation, then | |
504 | don't delete the derivation if any of the outputs are alive. */ | |
505 | if (state.gcKeepDerivations && isDerivation(path)) { | |
506 | PathSet outputs = queryDerivationOutputs(path); | |
507 | foreach (PathSet::iterator, i, outputs) | |
508 | if (isValidPath(*i) && queryDeriver(*i) == path) | |
509 | incoming.insert(*i); | |
510 | } | |
511 | ||
512 | /* If gc-keep-outputs is set, then don't delete this path if there | |
513 | are derivers of this path that are not garbage. */ | |
514 | if (state.gcKeepOutputs) { | |
515 | PathSet derivers = queryValidDerivers(path); | |
516 | foreach (PathSet::iterator, i, derivers) | |
517 | incoming.insert(*i); | |
518 | } | |
519 | ||
520 | foreach (PathSet::iterator, i, incoming) | |
521 | if (*i != path) | |
522 | if (canReachRoot(state, visited, *i)) { | |
523 | state.alive.insert(path); | |
524 | return true; | |
525 | } | |
526 | ||
527 | return false; | |
528 | } | |
529 | ||
530 | ||
531 | void LocalStore::tryToDelete(GCState & state, const Path & path) | |
532 | { | |
533 | checkInterrupt(); | |
534 | ||
535 | if (path == linksDir || path == state.trashDir) return; | |
536 | ||
537 | startNest(nest, lvlDebug, format("considering whether to delete `%1%'") % path); | |
538 | ||
539 | if (!isValidPath(path)) { | |
540 | /* A lock file belonging to a path that we're building right | |
541 | now isn't garbage. */ | |
542 | if (isActiveTempFile(state, path, ".lock")) return; | |
543 | ||
544 | /* Don't delete .chroot directories for derivations that are | |
545 | currently being built. */ | |
546 | if (isActiveTempFile(state, path, ".chroot")) return; | |
547 | } | |
548 | ||
549 | PathSet visited; | |
550 | ||
551 | if (canReachRoot(state, visited, path)) { | |
552 | printMsg(lvlDebug, format("cannot delete `%1%' because it's still reachable") % path); | |
553 | } else { | |
554 | /* No path we visited was a root, so everything is garbage. | |
555 | But we only delete ‘path’ and its referrers here so that | |
556 | ‘nix-store --delete’ doesn't have the unexpected effect of | |
557 | recursing into derivations and outputs. */ | |
558 | state.dead.insert(visited.begin(), visited.end()); | |
559 | if (state.shouldDelete) | |
560 | deletePathRecursive(state, path); | |
561 | } | |
562 | } | |
563 | ||
564 | ||
565 | /* Unlink all files in /nix/store/.links that have a link count of 1, | |
566 | which indicates that there are no other links and so they can be | |
567 | safely deleted. FIXME: race condition with optimisePath(): we | |
568 | might see a link count of 1 just before optimisePath() increases | |
569 | the link count. */ | |
570 | void LocalStore::removeUnusedLinks(const GCState & state) | |
571 | { | |
572 | AutoCloseDir dir = opendir(linksDir.c_str()); | |
573 | if (!dir) throw SysError(format("opening directory `%1%'") % linksDir); | |
574 | ||
575 | long long actualSize = 0, unsharedSize = 0; | |
576 | ||
577 | struct dirent * dirent; | |
578 | while (errno = 0, dirent = readdir(dir)) { | |
579 | checkInterrupt(); | |
580 | string name = dirent->d_name; | |
581 | if (name == "." || name == "..") continue; | |
582 | Path path = linksDir + "/" + name; | |
583 | ||
7738a721 LC |
584 | #ifdef HAVE_STATX |
585 | # define st_size stx_size | |
586 | # define st_nlink stx_nlink | |
513c0a0f | 587 | static int statx_flags = AT_SYMLINK_NOFOLLOW | AT_STATX_DONT_SYNC; |
7738a721 | 588 | struct statx st; |
513c0a0f LC |
589 | |
590 | if (statx(AT_FDCWD, path.c_str(), statx_flags, | |
591 | STATX_SIZE | STATX_NLINK, &st) == -1) { | |
592 | if (errno == EINVAL) { | |
593 | /* Old 3.10 kernels (CentOS 7) don't support | |
594 | AT_STATX_DONT_SYNC, so try again without it. */ | |
595 | statx_flags &= ~AT_STATX_DONT_SYNC; | |
596 | if (statx(AT_FDCWD, path.c_str(), statx_flags, | |
597 | STATX_SIZE | STATX_NLINK, &st) == -1) | |
598 | throw SysError(format("statting `%1%'") % path); | |
599 | } else { | |
600 | throw SysError(format("statting `%1%'") % path); | |
601 | } | |
602 | } | |
7738a721 | 603 | #else |
36457566 LC |
604 | struct stat st; |
605 | if (lstat(path.c_str(), &st) == -1) | |
606 | throw SysError(format("statting `%1%'") % path); | |
513c0a0f | 607 | #endif |
36457566 | 608 | |
472a0e82 LC |
609 | /* Drop links for files smaller than 'deduplicationMinSize', even if |
610 | they have more than one hard link. */ | |
611 | if (st.st_nlink != 1 && st.st_size >= deduplicationMinSize) { | |
546a709f ED |
612 | actualSize += st.st_size; |
613 | unsharedSize += (st.st_nlink - 1) * st.st_size; | |
36457566 LC |
614 | continue; |
615 | } | |
616 | ||
617 | printMsg(lvlTalkative, format("deleting unused link `%1%'") % path); | |
618 | ||
619 | if (unlink(path.c_str()) == -1) | |
620 | throw SysError(format("deleting `%1%'") % path); | |
621 | ||
546a709f | 622 | state.results.bytesFreed += st.st_size; |
7738a721 LC |
623 | #undef st_size |
624 | #undef st_nlink | |
36457566 LC |
625 | } |
626 | ||
627 | struct stat st; | |
628 | if (stat(linksDir.c_str(), &st) == -1) | |
629 | throw SysError(format("statting `%1%'") % linksDir); | |
546a709f | 630 | long long overhead = st.st_size; |
36457566 LC |
631 | |
632 | printMsg(lvlInfo, format("note: currently hard linking saves %.2f MiB") | |
633 | % ((unsharedSize - actualSize - overhead) / (1024.0 * 1024.0))); | |
634 | } | |
635 | ||
636 | ||
637 | void LocalStore::collectGarbage(const GCOptions & options, GCResults & results) | |
638 | { | |
639 | GCState state(results); | |
640 | state.options = options; | |
641 | state.trashDir = settings.nixStore + "/trash"; | |
642 | state.gcKeepOutputs = settings.gcKeepOutputs; | |
643 | state.gcKeepDerivations = settings.gcKeepDerivations; | |
644 | ||
645 | /* Using `--ignore-liveness' with `--delete' can have unintended | |
646 | consequences if `gc-keep-outputs' or `gc-keep-derivations' are | |
647 | true (the garbage collector will recurse into deleting the | |
648 | outputs or derivers, respectively). So disable them. */ | |
649 | if (options.action == GCOptions::gcDeleteSpecific && options.ignoreLiveness) { | |
650 | state.gcKeepOutputs = false; | |
651 | state.gcKeepDerivations = false; | |
652 | } | |
653 | ||
654 | state.shouldDelete = options.action == GCOptions::gcDeleteDead || options.action == GCOptions::gcDeleteSpecific; | |
655 | ||
656 | /* Acquire the global GC root. This prevents | |
657 | a) New roots from being added. | |
658 | b) Processes from creating new temporary root files. */ | |
659 | AutoCloseFD fdGCLock = openGCLock(ltWrite); | |
660 | ||
661 | /* Find the roots. Since we've grabbed the GC lock, the set of | |
662 | permanent roots cannot increase now. */ | |
663 | printMsg(lvlError, format("finding garbage collector roots...")); | |
664 | Roots rootMap = options.ignoreLiveness ? Roots() : findRoots(); | |
665 | ||
666 | foreach (Roots::iterator, i, rootMap) state.roots.insert(i->second); | |
667 | ||
47e99e62 LC |
668 | /* Add additional roots returned by 'guix gc --list-busy'. This is |
669 | typically used to add running programs to the set of roots (to prevent | |
670 | them from being garbage collected). */ | |
36457566 LC |
671 | if (!options.ignoreLiveness) |
672 | addAdditionalRoots(*this, state.roots); | |
673 | ||
674 | /* Read the temporary roots. This acquires read locks on all | |
675 | per-process temporary root files. So after this point no paths | |
676 | can be added to the set of temporary roots. */ | |
677 | FDs fds; | |
678 | readTempRoots(state.tempRoots, fds); | |
679 | state.roots.insert(state.tempRoots.begin(), state.tempRoots.end()); | |
680 | ||
681 | /* After this point the set of roots or temporary roots cannot | |
682 | increase, since we hold locks on everything. So everything | |
2bb04905 | 683 | that is not reachable from `roots' is garbage. */ |
36457566 LC |
684 | |
685 | if (state.shouldDelete) { | |
686 | if (pathExists(state.trashDir)) deleteGarbage(state, state.trashDir); | |
322eeb87 LC |
687 | try { |
688 | createDirs(state.trashDir); | |
689 | } catch (SysError & e) { | |
690 | if (e.errNo == ENOSPC) { | |
691 | printMsg(lvlInfo, format("note: can't create trash directory: %1%") % e.msg()); | |
692 | state.moveToTrash = false; | |
693 | } | |
694 | } | |
36457566 LC |
695 | } |
696 | ||
697 | /* Now either delete all garbage paths, or just the specified | |
698 | paths (for gcDeleteSpecific). */ | |
699 | ||
700 | if (options.action == GCOptions::gcDeleteSpecific) { | |
701 | ||
702 | foreach (PathSet::iterator, i, options.pathsToDelete) { | |
703 | assertStorePath(*i); | |
704 | tryToDelete(state, *i); | |
705 | if (state.dead.find(*i) == state.dead.end()) | |
706 | throw Error(format("cannot delete path `%1%' since it is still alive") % *i); | |
707 | } | |
708 | ||
709 | } else if (options.maxFreed > 0) { | |
710 | ||
711 | if (state.shouldDelete) | |
712 | printMsg(lvlError, format("deleting garbage...")); | |
713 | else | |
714 | printMsg(lvlError, format("determining live/dead paths...")); | |
715 | ||
716 | try { | |
717 | ||
718 | AutoCloseDir dir = opendir(settings.nixStore.c_str()); | |
719 | if (!dir) throw SysError(format("opening directory `%1%'") % settings.nixStore); | |
720 | ||
721 | /* Read the store and immediately delete all paths that | |
722 | aren't valid. When using --max-freed etc., deleting | |
723 | invalid paths is preferred over deleting unreachable | |
724 | paths, since unreachable paths could become reachable | |
725 | again. We don't use readDirectory() here so that GCing | |
726 | can start faster. */ | |
727 | Paths entries; | |
728 | struct dirent * dirent; | |
729 | while (errno = 0, dirent = readdir(dir)) { | |
730 | checkInterrupt(); | |
731 | string name = dirent->d_name; | |
732 | if (name == "." || name == "..") continue; | |
733 | Path path = settings.nixStore + "/" + name; | |
734 | if (isValidPath(path)) | |
735 | entries.push_back(path); | |
736 | else | |
737 | tryToDelete(state, path); | |
738 | } | |
739 | ||
740 | dir.close(); | |
741 | ||
742 | /* Now delete the unreachable valid paths. Randomise the | |
743 | order in which we delete entries to make the collector | |
744 | less biased towards deleting paths that come | |
745 | alphabetically first (e.g. /nix/store/000...). This | |
746 | matters when using --max-freed etc. */ | |
747 | vector<Path> entries_(entries.begin(), entries.end()); | |
748 | random_shuffle(entries_.begin(), entries_.end()); | |
749 | ||
750 | foreach (vector<Path>::iterator, i, entries_) | |
751 | tryToDelete(state, *i); | |
752 | ||
753 | } catch (GCLimitReached & e) { | |
754 | } | |
755 | } | |
756 | ||
757 | if (state.options.action == GCOptions::gcReturnLive) { | |
758 | state.results.paths = state.alive; | |
759 | return; | |
760 | } | |
761 | ||
762 | if (state.options.action == GCOptions::gcReturnDead) { | |
763 | state.results.paths = state.dead; | |
764 | return; | |
765 | } | |
766 | ||
767 | /* Allow other processes to add to the store from here on. */ | |
768 | fdGCLock.close(); | |
769 | fds.clear(); | |
770 | ||
771 | /* Delete the trash directory. */ | |
772 | printMsg(lvlInfo, format("deleting `%1%'") % state.trashDir); | |
773 | deleteGarbage(state, state.trashDir); | |
774 | ||
775 | /* Clean up the links directory. */ | |
776 | if (options.action == GCOptions::gcDeleteDead || options.action == GCOptions::gcDeleteSpecific) { | |
777 | printMsg(lvlError, format("deleting unused links...")); | |
778 | removeUnusedLinks(state); | |
779 | } | |
780 | ||
781 | /* While we're at it, vacuum the database. */ | |
2bb04905 | 782 | //if (options.action == GCOptions::gcDeleteDead) vacuumDB(); |
36457566 LC |
783 | } |
784 | ||
785 | ||
786 | } |