Initial commit

src/httpfetch.cpp

@@ -0,0 +1,848 @@
+/*
+Minetest
+Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include "httpfetch.h"
+#include "porting.h" // for sleep_ms(), get_sysinfo(), secure_rand_fill_buf()
+#include <iostream>
+#include <sstream>
+#include <list>
+#include <unordered_map>
+#include <cerrno>
+#include <mutex>
+#include "network/socket.h" // for select()
+#include "threading/event.h"
+#include "config.h"
+#include "exceptions.h"
+#include "debug.h"
+#include "log.h"
+#include "util/container.h"
+#include "util/thread.h"
+#include "version.h"
+#include "settings.h"
+#include "noise.h"
+
+static std::mutex g_httpfetch_mutex;
+static std::unordered_map<u64, std::queue<HTTPFetchResult>>
+	g_httpfetch_results;
+static PcgRandom g_callerid_randomness;
+
+HTTPFetchRequest::HTTPFetchRequest() :
+	timeout(g_settings->getS32("curl_timeout")),
+	connect_timeout(10 * 1000),
+	useragent(std::string(PROJECT_NAME_C "/") + g_version_hash + " (" + porting::get_sysinfo() + ")")
+{
+}
+
+
+static void httpfetch_deliver_result(const HTTPFetchResult &fetch_result)
+{
+	u64 caller = fetch_result.caller;
+	if (caller != HTTPFETCH_DISCARD) {
+		MutexAutoLock lock(g_httpfetch_mutex);
+		g_httpfetch_results[caller].emplace(fetch_result);
+	}
+}
+
+static void httpfetch_request_clear(u64 caller);
+
+u64 httpfetch_caller_alloc()
+{
+	MutexAutoLock lock(g_httpfetch_mutex);
+
+	// Check each caller ID except reserved ones
+	for (u64 caller = HTTPFETCH_CID_START; caller != 0; ++caller) {
+		auto it = g_httpfetch_results.find(caller);
+		if (it == g_httpfetch_results.end()) {
+			verbosestream << "httpfetch_caller_alloc: allocating "
+					<< caller << std::endl;
+			// Access element to create it
+			g_httpfetch_results[caller];
+			return caller;
+		}
+	}
+
+	FATAL_ERROR("httpfetch_caller_alloc: ran out of caller IDs");
+}
+
+u64 httpfetch_caller_alloc_secure()
+{
+	MutexAutoLock lock(g_httpfetch_mutex);
+
+	// Generate random caller IDs and make sure they're not
+	// already used or reserved.
+	// Give up after 100 tries to prevent infinite loop
+	size_t tries = 100;
+	u64 caller;
+
+	do {
+		caller = (((u64) g_callerid_randomness.next()) << 32) |
+				g_callerid_randomness.next();
+
+		if (--tries < 1) {
+			FATAL_ERROR("httpfetch_caller_alloc_secure: ran out of caller IDs");
+			return HTTPFETCH_DISCARD;
+		}
+	} while (caller >= HTTPFETCH_CID_START &&
+		g_httpfetch_results.find(caller) != g_httpfetch_results.end());
+
+	verbosestream << "httpfetch_caller_alloc_secure: allocating "
+		<< caller << std::endl;
+
+	// Access element to create it
+	g_httpfetch_results[caller];
+	return caller;
+}
+
+void httpfetch_caller_free(u64 caller)
+{
+	verbosestream<<"httpfetch_caller_free: freeing "
+			<<caller<<std::endl;
+
+	httpfetch_request_clear(caller);
+	if (caller != HTTPFETCH_DISCARD) {
+		MutexAutoLock lock(g_httpfetch_mutex);
+		g_httpfetch_results.erase(caller);
+	}
+}
+
+bool httpfetch_async_get(u64 caller, HTTPFetchResult &fetch_result)
+{
+	MutexAutoLock lock(g_httpfetch_mutex);
+
+	// Check that caller exists
+	auto it = g_httpfetch_results.find(caller);
+	if (it == g_httpfetch_results.end())
+		return false;
+
+	// Check that result queue is nonempty
+	std::queue<HTTPFetchResult> &caller_results = it->second;
+	if (caller_results.empty())
+		return false;
+
+	// Pop first result
+	fetch_result = std::move(caller_results.front());
+	caller_results.pop();
+	return true;
+}
+
+#if USE_CURL
+#include <curl/curl.h>
+
+/*
+	USE_CURL is on: use cURL based httpfetch implementation
+*/
+
+static size_t httpfetch_writefunction(
+		char *ptr, size_t size, size_t nmemb, void *userdata)
+{
+	std::ostringstream *stream = (std::ostringstream*)userdata;
+	size_t count = size * nmemb;
+	stream->write(ptr, count);
+	return count;
+}
+
+static size_t httpfetch_discardfunction(
+		char *ptr, size_t size, size_t nmemb, void *userdata)
+{
+	return size * nmemb;
+}
+
+class CurlHandlePool
+{
+	std::list<CURL*> handles;
+
+public:
+	CurlHandlePool() = default;
+
+	~CurlHandlePool()
+	{
+		for (std::list<CURL*>::iterator it = handles.begin();
+				it != handles.end(); ++it) {
+			curl_easy_cleanup(*it);
+		}
+	}
+	CURL * alloc()
+	{
+		CURL *curl;
+		if (handles.empty()) {
+			curl = curl_easy_init();
+			if (curl == NULL) {
+				errorstream<<"curl_easy_init returned NULL"<<std::endl;
+			}
+		}
+		else {
+			curl = handles.front();
+			handles.pop_front();
+		}
+		return curl;
+	}
+	void free(CURL *handle)
+	{
+		if (handle)
+			handles.push_back(handle);
+	}
+};
+
+class HTTPFetchOngoing
+{
+public:
+	HTTPFetchOngoing(const HTTPFetchRequest &request, CurlHandlePool *pool);
+	~HTTPFetchOngoing();
+
+	CURLcode start(CURLM *multi);
+	const HTTPFetchResult * complete(CURLcode res);
+
+	const HTTPFetchRequest &getRequest()    const { return request; };
+	const CURL             *getEasyHandle() const { return curl; };
+
+private:
+	CurlHandlePool *pool;
+	CURL *curl;
+	CURLM *multi;
+	HTTPFetchRequest request;
+	HTTPFetchResult result;
+	std::ostringstream oss;
+	struct curl_slist *http_header;
+	curl_httppost *post;
+};
+
+
+HTTPFetchOngoing::HTTPFetchOngoing(const HTTPFetchRequest &request_,
+		CurlHandlePool *pool_):
+	pool(pool_),
+	curl(NULL),
+	multi(NULL),
+	request(request_),
+	result(request_),
+	oss(std::ios::binary),
+	http_header(NULL),
+	post(NULL)
+{
+	curl = pool->alloc();
+	if (curl == NULL) {
+		return;
+	}
+
+	// Set static cURL options
+	curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1);
+	curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1);
+	curl_easy_setopt(curl, CURLOPT_MAXREDIRS, 3);
+	curl_easy_setopt(curl, CURLOPT_ENCODING, "gzip");
+
+	std::string bind_address = g_settings->get("bind_address");
+	if (!bind_address.empty()) {
+		curl_easy_setopt(curl, CURLOPT_INTERFACE, bind_address.c_str());
+	}
+
+	if (!g_settings->getBool("enable_ipv6")) {
+		curl_easy_setopt(curl, CURLOPT_IPRESOLVE, CURL_IPRESOLVE_V4);
+	}
+
+#if LIBCURL_VERSION_NUM >= 0x071304
+	// Restrict protocols so that curl vulnerabilities in
+	// other protocols don't affect us.
+	// These settings were introduced in curl 7.19.4.
+	long protocols =
+		CURLPROTO_HTTP |
+		CURLPROTO_HTTPS |
+		CURLPROTO_FTP |
+		CURLPROTO_FTPS;
+	curl_easy_setopt(curl, CURLOPT_PROTOCOLS, protocols);
+	curl_easy_setopt(curl, CURLOPT_REDIR_PROTOCOLS, protocols);
+#endif
+
+	// Set cURL options based on HTTPFetchRequest
+	curl_easy_setopt(curl, CURLOPT_URL,
+			request.url.c_str());
+	curl_easy_setopt(curl, CURLOPT_TIMEOUT_MS,
+			request.timeout);
+	curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT_MS,
+			request.connect_timeout);
+
+	if (!request.useragent.empty())
+		curl_easy_setopt(curl, CURLOPT_USERAGENT, request.useragent.c_str());
+
+	// Set up a write callback that writes to the
+	// ostringstream ongoing->oss, unless the data
+	// is to be discarded
+	if (request.caller == HTTPFETCH_DISCARD) {
+		curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION,
+				httpfetch_discardfunction);
+		curl_easy_setopt(curl, CURLOPT_WRITEDATA, NULL);
+	} else {
+		curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION,
+				httpfetch_writefunction);
+		curl_easy_setopt(curl, CURLOPT_WRITEDATA, &oss);
+	}
+
+	// Set data from fields or raw_data
+	if (request.multipart) {
+		curl_httppost *last = NULL;
+		for (StringMap::iterator it = request.fields.begin();
+				it != request.fields.end(); ++it) {
+			curl_formadd(&post, &last,
+					CURLFORM_NAMELENGTH, it->first.size(),
+					CURLFORM_PTRNAME, it->first.c_str(),
+					CURLFORM_CONTENTSLENGTH, it->second.size(),
+					CURLFORM_PTRCONTENTS, it->second.c_str(),
+					CURLFORM_END);
+		}
+		curl_easy_setopt(curl, CURLOPT_HTTPPOST, post);
+		// request.post_fields must now *never* be
+		// modified until CURLOPT_HTTPPOST is cleared
+	} else {
+		switch (request.method) {
+		case HTTP_GET:
+			curl_easy_setopt(curl, CURLOPT_HTTPGET, 1);
+			break;
+		case HTTP_POST:
+			curl_easy_setopt(curl, CURLOPT_POST, 1);
+			break;
+		case HTTP_PUT:
+			curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "PUT");
+			break;
+		case HTTP_DELETE:
+			curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "DELETE");
+			break;
+		}
+		if (request.method != HTTP_GET) {
+			if (!request.raw_data.empty()) {
+				curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE,
+						request.raw_data.size());
+				curl_easy_setopt(curl, CURLOPT_POSTFIELDS,
+						request.raw_data.c_str());
+			} else if (!request.fields.empty()) {
+				std::string str;
+				for (auto &field : request.fields) {
+					if (!str.empty())
+						str += "&";
+					str += urlencode(field.first);
+					str += "=";
+					str += urlencode(field.second);
+				}
+				curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE,
+						str.size());
+				curl_easy_setopt(curl, CURLOPT_COPYPOSTFIELDS,
+						str.c_str());
+			}
+		}
+	}
+	// Set additional HTTP headers
+	for (const std::string &extra_header : request.extra_headers) {
+		http_header = curl_slist_append(http_header, extra_header.c_str());
+	}
+	curl_easy_setopt(curl, CURLOPT_HTTPHEADER, http_header);
+
+	if (!g_settings->getBool("curl_verify_cert")) {
+		curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, false);
+	}
+}
+
+CURLcode HTTPFetchOngoing::start(CURLM *multi_)
+{
+	if (!curl)
+		return CURLE_FAILED_INIT;
+
+	if (!multi_) {
+		// Easy interface (sync)
+		return curl_easy_perform(curl);
+	}
+
+	// Multi interface (async)
+	CURLMcode mres = curl_multi_add_handle(multi_, curl);
+	if (mres != CURLM_OK) {
+		errorstream << "curl_multi_add_handle"
+			<< " returned error code " << mres
+			<< std::endl;
+		return CURLE_FAILED_INIT;
+	}
+	multi = multi_; // store for curl_multi_remove_handle
+	return CURLE_OK;
+}
+
+const HTTPFetchResult * HTTPFetchOngoing::complete(CURLcode res)
+{
+	result.succeeded = (res == CURLE_OK);
+	result.timeout = (res == CURLE_OPERATION_TIMEDOUT);
+	result.data = oss.str();
+
+	// Get HTTP/FTP response code
+	result.response_code = 0;
+	if (curl && (curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE,
+				&result.response_code) != CURLE_OK)) {
+		// We failed to get a return code, make sure it is still 0
+		result.response_code = 0;
+	}
+
+	if (res != CURLE_OK) {
+		errorstream << "HTTPFetch for " << request.url << " failed ("
+			<< curl_easy_strerror(res) << ")" << std::endl;
+	} else if (result.response_code >= 400) {
+		errorstream << "HTTPFetch for " << request.url
+			<< " returned response code " << result.response_code
+			<< std::endl;
+		if (result.caller == HTTPFETCH_PRINT_ERR && !result.data.empty()) {
+			errorstream << "Response body:" << std::endl;
+			safe_print_string(errorstream, result.data);
+			errorstream << std::endl;
+		}
+	}
+
+	return &result;
+}
+
+HTTPFetchOngoing::~HTTPFetchOngoing()
+{
+	if (multi) {
+		CURLMcode mres = curl_multi_remove_handle(multi, curl);
+		if (mres != CURLM_OK) {
+			errorstream << "curl_multi_remove_handle"
+				<< " returned error code " << mres
+				<< std::endl;
+		}
+	}
+
+	// Set safe options for the reusable cURL handle
+	curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION,
+			httpfetch_discardfunction);
+	curl_easy_setopt(curl, CURLOPT_WRITEDATA, NULL);
+	curl_easy_setopt(curl, CURLOPT_POSTFIELDS, NULL);
+	if (http_header) {
+		curl_easy_setopt(curl, CURLOPT_HTTPHEADER, NULL);
+		curl_slist_free_all(http_header);
+	}
+	if (post) {
+		curl_easy_setopt(curl, CURLOPT_HTTPPOST, NULL);
+		curl_formfree(post);
+	}
+
+	// Store the cURL handle for reuse
+	pool->free(curl);
+}
+
+
+class CurlFetchThread : public Thread
+{
+protected:
+	enum RequestType {
+		RT_FETCH,
+		RT_CLEAR,
+		RT_WAKEUP,
+	};
+
+	struct Request {
+		RequestType type;
+		HTTPFetchRequest fetch_request;
+		Event *event;
+	};
+
+	CURLM *m_multi;
+	MutexedQueue<Request> m_requests;
+	size_t m_parallel_limit;
+
+	// Variables exclusively used within thread
+	std::vector<HTTPFetchOngoing*> m_all_ongoing;
+	std::list<HTTPFetchRequest> m_queued_fetches;
+
+public:
+	CurlFetchThread(int parallel_limit) :
+		Thread("CurlFetch")
+	{
+		if (parallel_limit >= 1)
+			m_parallel_limit = parallel_limit;
+		else
+			m_parallel_limit = 1;
+	}
+
+	void requestFetch(const HTTPFetchRequest &fetch_request)
+	{
+		Request req;
+		req.type = RT_FETCH;
+		req.fetch_request = fetch_request;
+		req.event = NULL;
+		m_requests.push_back(req);
+	}
+
+	void requestClear(u64 caller, Event *event)
+	{
+		Request req;
+		req.type = RT_CLEAR;
+		req.fetch_request.caller = caller;
+		req.event = event;
+		m_requests.push_back(req);
+	}
+
+	void requestWakeUp()
+	{
+		Request req;
+		req.type = RT_WAKEUP;
+		req.event = NULL;
+		m_requests.push_back(req);
+	}
+
+protected:
+	// Handle a request from some other thread
+	// E.g. new fetch; clear fetches for one caller; wake up
+	void processRequest(const Request &req)
+	{
+		if (req.type == RT_FETCH) {
+			// New fetch, queue until there are less
+			// than m_parallel_limit ongoing fetches
+			m_queued_fetches.push_back(req.fetch_request);
+
+			// see processQueued() for what happens next
+
+		}
+		else if (req.type == RT_CLEAR) {
+			u64 caller = req.fetch_request.caller;
+
+			// Abort all ongoing fetches for the caller
+			for (std::vector<HTTPFetchOngoing*>::iterator
+					it = m_all_ongoing.begin();
+					it != m_all_ongoing.end();) {
+				if ((*it)->getRequest().caller == caller) {
+					delete (*it);
+					it = m_all_ongoing.erase(it);
+				} else {
+					++it;
+				}
+			}
+
+			// Also abort all queued fetches for the caller
+			for (std::list<HTTPFetchRequest>::iterator
+					it = m_queued_fetches.begin();
+					it != m_queued_fetches.end();) {
+				if ((*it).caller == caller)
+					it = m_queued_fetches.erase(it);
+				else
+					++it;
+			}
+		}
+		else if (req.type == RT_WAKEUP) {
+			// Wakeup: Nothing to do, thread is awake at this point
+		}
+
+		if (req.event != NULL)
+			req.event->signal();
+	}
+
+	// Start new ongoing fetches if m_parallel_limit allows
+	void processQueued(CurlHandlePool *pool)
+	{
+		while (m_all_ongoing.size() < m_parallel_limit &&
+				!m_queued_fetches.empty()) {
+			HTTPFetchRequest request = m_queued_fetches.front();
+			m_queued_fetches.pop_front();
+
+			// Create ongoing fetch data and make a cURL handle
+			// Set cURL options based on HTTPFetchRequest
+			HTTPFetchOngoing *ongoing =
+				new HTTPFetchOngoing(request, pool);
+
+			// Initiate the connection (curl_multi_add_handle)
+			CURLcode res = ongoing->start(m_multi);
+			if (res == CURLE_OK) {
+				m_all_ongoing.push_back(ongoing);
+			}
+			else {
+				httpfetch_deliver_result(*ongoing->complete(res));
+				delete ongoing;
+			}
+		}
+	}
+
+	// Process CURLMsg (indicates completion of a fetch)
+	void processCurlMessage(CURLMsg *msg)
+	{
+		// Determine which ongoing fetch the message pertains to
+		size_t i = 0;
+		bool found = false;
+		for (i = 0; i < m_all_ongoing.size(); ++i) {
+			if (m_all_ongoing[i]->getEasyHandle() == msg->easy_handle) {
+				found = true;
+				break;
+			}
+		}
+		if (msg->msg == CURLMSG_DONE && found) {
+			// m_all_ongoing[i] succeeded or failed.
+			HTTPFetchOngoing *ongoing = m_all_ongoing[i];
+			httpfetch_deliver_result(*ongoing->complete(msg->data.result));
+			delete ongoing;
+			m_all_ongoing.erase(m_all_ongoing.begin() + i);
+		}
+	}
+
+	// Wait for a request from another thread, or timeout elapses
+	void waitForRequest(long timeout)
+	{
+		if (m_queued_fetches.empty()) {
+			try {
+				Request req = m_requests.pop_front(timeout);
+				processRequest(req);
+			}
+			catch (ItemNotFoundException &e) {}
+		}
+	}
+
+	// Wait until some IO happens, or timeout elapses
+	void waitForIO(long timeout)
+	{
+		fd_set read_fd_set;
+		fd_set write_fd_set;
+		fd_set exc_fd_set;
+		int max_fd;
+		long select_timeout = -1;
+		struct timeval select_tv;
+		CURLMcode mres;
+
+		FD_ZERO(&read_fd_set);
+		FD_ZERO(&write_fd_set);
+		FD_ZERO(&exc_fd_set);
+
+		mres = curl_multi_fdset(m_multi, &read_fd_set,
+				&write_fd_set, &exc_fd_set, &max_fd);
+		if (mres != CURLM_OK) {
+			errorstream<<"curl_multi_fdset"
+				<<" returned error code "<<mres
+				<<std::endl;
+			select_timeout = 0;
+		}
+
+		mres = curl_multi_timeout(m_multi, &select_timeout);
+		if (mres != CURLM_OK) {
+			errorstream<<"curl_multi_timeout"
+				<<" returned error code "<<mres
+				<<std::endl;
+			select_timeout = 0;
+		}
+
+		// Limit timeout so new requests get through
+		if (select_timeout < 0 || select_timeout > timeout)
+			select_timeout = timeout;
+
+		if (select_timeout > 0) {
+			// in Winsock it is forbidden to pass three empty
+			// fd_sets to select(), so in that case use sleep_ms
+			if (max_fd != -1) {
+				select_tv.tv_sec = select_timeout / 1000;
+				select_tv.tv_usec = (select_timeout % 1000) * 1000;
+				int retval = select(max_fd + 1, &read_fd_set,
+						&write_fd_set, &exc_fd_set,
+						&select_tv);
+				if (retval == -1) {
+					#ifdef _WIN32
+					errorstream<<"select returned error code "
+						<<WSAGetLastError()<<std::endl;
+					#else
+					errorstream<<"select returned error code "
+						<<errno<<std::endl;
+					#endif
+				}
+			}
+			else {
+				sleep_ms(select_timeout);
+			}
+		}
+	}
+
+	void *run()
+	{
+		CurlHandlePool pool;
+
+		m_multi = curl_multi_init();
+		if (m_multi == NULL) {
+			errorstream<<"curl_multi_init returned NULL\n";
+			return NULL;
+		}
+
+		FATAL_ERROR_IF(!m_all_ongoing.empty(), "Expected empty");
+
+		while (!stopRequested()) {
+			BEGIN_DEBUG_EXCEPTION_HANDLER
+
+			/*
+				Handle new async requests
+			*/
+
+			while (!m_requests.empty()) {
+				Request req = m_requests.pop_frontNoEx();
+				processRequest(req);
+			}
+			processQueued(&pool);
+
+			/*
+				Handle ongoing async requests
+			*/
+
+			int still_ongoing = 0;
+			while (curl_multi_perform(m_multi, &still_ongoing) ==
+					CURLM_CALL_MULTI_PERFORM)
+				/* noop */;
+
+			/*
+				Handle completed async requests
+			*/
+			if (still_ongoing < (int) m_all_ongoing.size()) {
+				CURLMsg *msg;
+				int msgs_in_queue;
+				msg = curl_multi_info_read(m_multi, &msgs_in_queue);
+				while (msg != NULL) {
+					processCurlMessage(msg);
+					msg = curl_multi_info_read(m_multi, &msgs_in_queue);
+				}
+			}
+
+			/*
+				If there are ongoing requests, wait for data
+				(with a timeout of 100ms so that new requests
+				can be processed).
+
+				If no ongoing requests, wait for a new request.
+				(Possibly an empty request that signals
+				that the thread should be stopped.)
+			*/
+			if (m_all_ongoing.empty())
+				waitForRequest(100000000);
+			else
+				waitForIO(100);
+
+			END_DEBUG_EXCEPTION_HANDLER
+		}
+
+		// Call curl_multi_remove_handle and cleanup easy handles
+		for (HTTPFetchOngoing *i : m_all_ongoing) {
+			delete i;
+		}
+		m_all_ongoing.clear();
+
+		m_queued_fetches.clear();
+
+		CURLMcode mres = curl_multi_cleanup(m_multi);
+		if (mres != CURLM_OK) {
+			errorstream<<"curl_multi_cleanup"
+				<<" returned error code "<<mres
+				<<std::endl;
+		}
+
+		return NULL;
+	}
+};
+
+CurlFetchThread *g_httpfetch_thread = NULL;
+
+void httpfetch_init(int parallel_limit)
+{
+	verbosestream<<"httpfetch_init: parallel_limit="<<parallel_limit
+			<<std::endl;
+
+	CURLcode res = curl_global_init(CURL_GLOBAL_DEFAULT);
+	FATAL_ERROR_IF(res != CURLE_OK, "CURL init failed");
+
+	g_httpfetch_thread = new CurlFetchThread(parallel_limit);
+
+	// Initialize g_callerid_randomness for httpfetch_caller_alloc_secure
+	u64 randbuf[2];
+	porting::secure_rand_fill_buf(randbuf, sizeof(u64) * 2);
+	g_callerid_randomness = PcgRandom(randbuf[0], randbuf[1]);
+}
+
+void httpfetch_cleanup()
+{
+	verbosestream<<"httpfetch_cleanup: cleaning up"<<std::endl;
+
+	if (g_httpfetch_thread) {
+		g_httpfetch_thread->stop();
+		g_httpfetch_thread->requestWakeUp();
+		g_httpfetch_thread->wait();
+		delete g_httpfetch_thread;
+	}
+
+	curl_global_cleanup();
+}
+
+void httpfetch_async(const HTTPFetchRequest &fetch_request)
+{
+	g_httpfetch_thread->requestFetch(fetch_request);
+	if (!g_httpfetch_thread->isRunning())
+		g_httpfetch_thread->start();
+}
+
+static void httpfetch_request_clear(u64 caller)
+{
+	if (g_httpfetch_thread->isRunning()) {
+		Event event;
+		g_httpfetch_thread->requestClear(caller, &event);
+		event.wait();
+	} else {
+		g_httpfetch_thread->requestClear(caller, NULL);
+	}
+}
+
+void httpfetch_sync(const HTTPFetchRequest &fetch_request,
+		HTTPFetchResult &fetch_result)
+{
+	// Create ongoing fetch data and make a cURL handle
+	// Set cURL options based on HTTPFetchRequest
+	CurlHandlePool pool;
+	HTTPFetchOngoing ongoing(fetch_request, &pool);
+	// Do the fetch (curl_easy_perform)
+	CURLcode res = ongoing.start(NULL);
+	// Update fetch result
+	fetch_result = *ongoing.complete(res);
+}
+
+#else  // USE_CURL
+
+/*
+	USE_CURL is off:
+
+	Dummy httpfetch implementation that always returns an error.
+*/
+
+void httpfetch_init(int parallel_limit)
+{
+}
+
+void httpfetch_cleanup()
+{
+}
+
+void httpfetch_async(const HTTPFetchRequest &fetch_request)
+{
+	errorstream << "httpfetch_async: unable to fetch " << fetch_request.url
+			<< " because USE_CURL=0" << std::endl;
+
+	HTTPFetchResult fetch_result(fetch_request); // sets succeeded = false etc.
+	httpfetch_deliver_result(fetch_result);
+}
+
+static void httpfetch_request_clear(u64 caller)
+{
+}
+
+void httpfetch_sync(const HTTPFetchRequest &fetch_request,
+		HTTPFetchResult &fetch_result)
+{
+	errorstream << "httpfetch_sync: unable to fetch " << fetch_request.url
+			<< " because USE_CURL=0" << std::endl;
+
+	fetch_result = HTTPFetchResult(fetch_request); // sets succeeded = false etc.
+}
+
+#endif  // USE_CURL