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* In addPermRoot, check that the root that we just registered can be

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found by the garbage collector.  This addresses NIX-71 and is a
  particular concern in multi-user stores.
This commit is contained in:
Eelco Dolstra 2006-12-05 00:34:42 +00:00
parent 74033a844f
commit d27a73b1a9
2 changed files with 42 additions and 18 deletions
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2
src/libmain/shared.cc
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@ -47,7 +47,7 @@ void printGCWarning()
{
static bool haveWarned = false;
warnOnce(haveWarned,
"warning: you did not specify `--add-root'; "
"you did not specify `--add-root'; "
"the result might be removed by the garbage collector");
}

58
src/libstore/gc.cc
View file

@ -91,6 +91,9 @@ void LocalStore::addIndirectRoot(const Path & path)
}
static void findRoots(PathSet & roots, bool ignoreUnreadable);
Path addPermRoot(const Path & _storePath, const Path & _gcRoot,
bool indirect, bool allowOutsideRootsDir)
{
@ -115,6 +118,18 @@ Path addPermRoot(const Path & _storePath, const Path & _gcRoot,
}
createSymlink(gcRoot, storePath, false);
/* Check that the root can be found by the garbage collector. */
PathSet roots;
findRoots(roots, true);
if (roots.find(storePath) == roots.end()) {
static bool haveWarned = false;
warnOnce(haveWarned,
format(
"the path `%1%' is not reachable from the roots directory of the garbage collector; "
"therefore, `%2%' might be removed by the garbage collector")
% gcRoot % storePath);
}
}
/* Grab the global GC root, causing us to block while a GC is in
@ -292,7 +307,7 @@ static void readTempRoots(PathSet & tempRoots, FDs & fds)
static void findRoots(const Path & path, bool recurseSymlinks,
PathSet & roots)
bool ignoreUnreadable, PathSet & roots)
{
struct stat st;
if (lstat(path.c_str(), &st) == -1)
@ -303,39 +318,50 @@ static void findRoots(const Path & path, bool recurseSymlinks,
if (S_ISDIR(st.st_mode)) {
Strings names = readDirectory(path);
for (Strings::iterator i = names.begin(); i != names.end(); ++i)
findRoots(path + "/" + *i, recurseSymlinks, roots);
findRoots(path + "/" + *i, recurseSymlinks, ignoreUnreadable, roots);
}
else if (S_ISLNK(st.st_mode)) {
string target = readLink(path);
Path target2 = absPath(target, dirOf(path));
Path target = absPath(readLink(path), dirOf(path));
if (isInStore(target2)) {
if (isInStore(target)) {
debug(format("found root `%1%' in `%2%'")
% target2 % path);
Path target3 = toStorePath(target2);
if (store->isValidPath(target3))
roots.insert(target3);
% target % path);
Path storePath = toStorePath(target);
if (store->isValidPath(storePath))
roots.insert(storePath);
else
printMsg(lvlInfo, format("skipping invalid root from `%1%' to `%2%'")
% path % target3);
% path % storePath);
}
else if (recurseSymlinks) {
if (pathExists(target2))
findRoots(target2, false, roots);
else {
printMsg(lvlInfo, format("removing stale link from `%1%' to `%2%'") % path % target2);
struct stat st2;
if (lstat(target.c_str(), &st2) == 0)
findRoots(target, false, ignoreUnreadable, roots);
else if (ignoreUnreadable && errno == EACCES)
/* ignore */ ;
else if (errno == ENOENT || errno == ENOTDIR) {
printMsg(lvlInfo, format("removing stale link from `%1%' to `%2%'") % path % target);
/* Note that we only delete when recursing, i.e., when
we are still in the `gcroots' tree. We never
delete stuff outside that tree. */
unlink(path.c_str());
}
else
throw SysError(format("statting `%1%'") % target);
}
}
}
static void findRoots(PathSet & roots, bool ignoreUnreadable)
{
Path rootsDir = canonPath((format("%1%/%2%") % nixStateDir % gcRootsDir).str());
findRoots(rootsDir, true, ignoreUnreadable, roots);
}
static void addAdditionalRoots(PathSet & roots)
{
Path rootFinder = getEnv("NIX_ROOT_FINDER",
@ -410,10 +436,8 @@ void collectGarbage(GCAction action, const PathSet & pathsToDelete,
/* Find the roots. Since we've grabbed the GC lock, the set of
permanent roots cannot increase now. */
Path rootsDir = canonPath((format("%1%/%2%") % nixStateDir % gcRootsDir).str());
PathSet roots;
if (!ignoreLiveness)
findRoots(rootsDir, true, roots);
findRoots(roots, false);
/* Add additional roots returned by the program specified by the
NIX_ROOT_FINDER environment variable. This is typically used