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Added locks to avoid race conditions in FsBlobStore

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This commit is contained in:
Sebastian Messmer 2015-10-04 17:37:00 +02:00
parent 1977a720df
commit 0367df004e
2 changed files with 15 additions and 3 deletions
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14
src/filesystem/fsblobstore/DirBlob.cpp
View File

@ -49,6 +49,7 @@ unique_ref<DirBlob> DirBlob::InitializeEmptyDir(unique_ref<Blob> blob, std::func
}
void DirBlob::_writeEntriesToBlob() {
std::unique_lock<std::mutex> lock(_mutex);
if (_changed) {
//TODO Resizing is imperformant
baseBlob().resize(1);
@ -75,6 +76,7 @@ void DirBlob::_writeEntriesToBlob() {
}
void DirBlob::_readEntriesFromBlob() {
//No lock needed, because this is only called from the constructor.
_entries.clear();
//TODO Getting size and then reading traverses tree twice. Something like readAll() would be faster.
Data data(baseBlob().size() - 1);
@ -116,7 +118,7 @@ const char *DirBlob::readAndAddNextChild(const char *pos,
return pos;
}
bool DirBlob::hasChild(const string &name) const {
bool DirBlob::_hasChild(const string &name) const {
auto found = std::find_if(_entries.begin(), _entries.end(), [name] (const Entry &entry) {
return entry.name == name;
});
@ -137,7 +139,8 @@ void DirBlob::AddChildSymlink(const std::string &name, const blockstore::Key &bl
void DirBlob::AddChild(const std::string &name, const Key &blobKey,
fspp::Dir::EntryType entryType, mode_t mode, uid_t uid, gid_t gid) {
if (hasChild(name)) {
std::unique_lock<std::mutex> lock(_mutex);
if (_hasChild(name)) {
throw fspp::fuse::FuseErrnoException(EEXIST);
}
@ -146,6 +149,7 @@ void DirBlob::AddChild(const std::string &name, const Key &blobKey,
}
const DirBlob::Entry &DirBlob::GetChild(const string &name) const {
std::unique_lock<std::mutex> lock(_mutex);
auto found = std::find_if(_entries.begin(), _entries.end(), [name] (const Entry &entry) {
return entry.name == name;
});
@ -156,6 +160,7 @@ const DirBlob::Entry &DirBlob::GetChild(const string &name) const {
}
const DirBlob::Entry &DirBlob::GetChild(const Key &key) const {
std::unique_lock<std::mutex> lock(_mutex);
auto found = std::find_if(_entries.begin(), _entries.end(), [key] (const Entry &entry) {
return entry.key == key;
});
@ -166,6 +171,7 @@ const DirBlob::Entry &DirBlob::GetChild(const Key &key) const {
}
void DirBlob::RemoveChild(const Key &key) {
std::unique_lock<std::mutex> lock(_mutex);
auto found = _findChild(key);
_entries.erase(found);
_changed = true;
@ -183,6 +189,7 @@ std::vector<DirBlob::Entry>::iterator DirBlob::_findChild(const Key &key) {
}
void DirBlob::AppendChildrenTo(vector<fspp::Dir::Entry> *result) const {
std::unique_lock<std::mutex> lock(_mutex);
result->reserve(result->size() + _entries.size());
for (const auto &entry : _entries) {
result->emplace_back(entry.type, entry.name);
@ -212,6 +219,7 @@ void DirBlob::statChild(const Key &key, struct ::stat *result) const {
}
void DirBlob::chmodChild(const Key &key, mode_t mode) {
std::unique_lock<std::mutex> lock(_mutex);
auto found = _findChild(key);
ASSERT ((S_ISREG(mode) && S_ISREG(found->mode)) || (S_ISDIR(mode) && S_ISDIR(found->mode)) || (S_ISLNK(mode)), "Unknown mode in entry");
found->mode = mode;
@ -219,6 +227,7 @@ void DirBlob::chmodChild(const Key &key, mode_t mode) {
}
void DirBlob::chownChild(const Key &key, uid_t uid, gid_t gid) {
std::unique_lock<std::mutex> lock(_mutex);
auto found = _findChild(key);
if (uid != (uid_t)-1) {
found->uid = uid;
@ -231,6 +240,7 @@ void DirBlob::chownChild(const Key &key, uid_t uid, gid_t gid) {
}
void DirBlob::setLstatSizeGetter(std::function<off_t(const blockstore::Key&)> getLstatSize) {
std::unique_lock<std::mutex> lock(_mutex);
_getLstatSize = getLstatSize;
}

4
src/filesystem/fsblobstore/DirBlob.h
View File

@ -7,6 +7,7 @@
#include <messmer/fspp/fs_interface/Dir.h>
#include "FsBlob.h"
#include <vector>
#include <mutex>
namespace cryfs {
namespace fsblobstore {
@ -84,7 +85,7 @@ namespace cryfs {
const char *readAndAddNextChild(const char *pos, std::vector<Entry> *result) const;
bool hasChild(const std::string &name) const;
bool _hasChild(const std::string &name) const;
void _readEntriesFromBlob();
@ -94,6 +95,7 @@ namespace cryfs {
std::function<off_t (const blockstore::Key&)> _getLstatSize;
std::vector<Entry> _entries;
mutable std::mutex _mutex;
bool _changed;
DISALLOW_COPY_AND_ASSIGN(DirBlob);