ZeroTierOne/controller/JSONDB.cpp
2016-11-04 15:34:49 -07:00

167 lines
4.6 KiB
C++

/*
* ZeroTier One - Network Virtualization Everywhere
* Copyright (C) 2011-2015 ZeroTier, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "JSONDB.hpp"
namespace ZeroTier {
static const nlohmann::json _EMPTY_JSON(nlohmann::json::object());
bool JSONDB::put(const std::string &n,const nlohmann::json &obj)
{
if (!_isValidObjectName(n))
return false;
std::string path(_genPath(n,true));
if (!path.length())
return false;
std::string buf(obj.dump(2));
if (!OSUtils::writeFile(path.c_str(),buf))
return false;
_E &e = _db[n];
e.obj = obj;
e.lastModifiedOnDisk = OSUtils::getLastModified(path.c_str());
e.lastCheck = OSUtils::now();
return true;
}
const nlohmann::json &JSONDB::get(const std::string &n,unsigned long maxSinceCheck)
{
if (!_isValidObjectName(n))
return _EMPTY_JSON;
const uint64_t now = OSUtils::now();
std::string buf;
std::map<std::string,_E>::iterator e(_db.find(n));
if (e != _db.end()) {
if ((now - e->second.lastCheck) <= (uint64_t)maxSinceCheck)
return e->second.obj;
std::string path(_genPath(n,false));
if (!path.length()) // sanity check
return _EMPTY_JSON;
// We are somewhat tolerant to momentary disk failures here. This may
// occur over e.g. EC2's elastic filesystem (NFS).
const uint64_t lm = OSUtils::getLastModified(path.c_str());
if (e->second.lastModifiedOnDisk != lm) {
if (OSUtils::readFile(path.c_str(),buf)) {
try {
e->second.obj = nlohmann::json::parse(buf);
e->second.lastModifiedOnDisk = lm; // don't update these if there is a parse error -- try again and again ASAP
e->second.lastCheck = now;
} catch ( ... ) {} // parse errors result in "holding pattern" behavior
}
}
return e->second.obj;
} else {
std::string path(_genPath(n,false));
if (!path.length())
return _EMPTY_JSON;
if (!OSUtils::readFile(path.c_str(),buf))
return _EMPTY_JSON;
const uint64_t lm = OSUtils::getLastModified(path.c_str());
_E &e2 = _db[n];
try {
e2.obj = nlohmann::json::parse(buf);
} catch ( ... ) {
e2.obj = _EMPTY_JSON;
}
e2.lastModifiedOnDisk = lm;
e2.lastCheck = now;
return e2.obj;
}
}
void JSONDB::erase(const std::string &n)
{
if (!_isValidObjectName(n))
return;
std::string path(_genPath(n,true));
if (!path.length())
return;
OSUtils::rm(path.c_str());
_db.erase(n);
}
void JSONDB::_reload(const std::string &p)
{
std::map<std::string,char> l(OSUtils::listDirectoryFull(p.c_str()));
for(std::map<std::string,char>::iterator li(l.begin());li!=l.end();++li) {
if (li->second == 'f') {
// assume p starts with _basePath, which it always does -- will throw otherwise
std::string n(p.substr(_basePath.length()));
while ((n.length() > 0)&&(n[0] == ZT_PATH_SEPARATOR)) n = n.substr(1);
if (ZT_PATH_SEPARATOR != '/') std::replace(n.begin(),n.end(),ZT_PATH_SEPARATOR,'/');
if ((n.length() > 0)&&(n[n.length() - 1] != '/')) n.push_back('/');
n.append(li->first);
this->get(n,0); // causes load and cache or update
} else if (li->second == 'd') {
this->_reload(p + ZT_PATH_SEPARATOR + li->first);
}
}
}
bool JSONDB::_isValidObjectName(const std::string &n)
{
if (n.length() == 0)
return false;
const char *p = n.c_str();
char c;
// For security reasons we should not allow dots, backslashes, or other path characters or potential path characters.
while ((c = *(p++))) {
if (!( ((c >= 'a')&&(c <= 'z')) || ((c >= 'A')&&(c <= 'Z')) || ((c >= '0')&&(c <= '9')) || (c == '/') || (c == '_') || (c == '~') || (c == '-') ))
return false;
}
return true;
}
std::string JSONDB::_genPath(const std::string &n,bool create)
{
std::vector<std::string> pt(Utils::split(n.c_str(),"/","",""));
if (pt.size() == 0)
return std::string();
if (pt.size() == 1)
return pt[0];
std::string p(_basePath);
if (create) OSUtils::mkdir(p.c_str());
for(unsigned long i=0,j=pt.size()-1;i<j;++i) {
p.push_back(ZT_PATH_SEPARATOR);
p.append(pt[i]);
if (create) OSUtils::mkdir(p.c_str());
}
p.push_back(ZT_PATH_SEPARATOR);
p.append(pt[pt.size()-1]);
p.append(".json");
return p;
}
} // namespace ZeroTier