mpd/src/lib/curl/Global.cxx

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/*
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* Copyright (C) 2008-2016 Max Kellermann <max.kellermann@gmail.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "Global.hxx"
#include "Request.hxx"
#include "Log.hxx"
#include "event/Loop.hxx"
#include "event/SocketMonitor.hxx"
#include "util/RuntimeError.hxx"
#include "util/Domain.hxx"
static constexpr Domain curlm_domain("curlm");
/**
* Monitor for one socket created by CURL.
*/
class CurlSocket final : SocketMonitor {
CurlGlobal &global;
public:
CurlSocket(CurlGlobal &_global, EventLoop &_loop, SocketDescriptor _fd)
:SocketMonitor(_fd, _loop), global(_global) {}
~CurlSocket() {
/* TODO: sometimes, CURL uses CURL_POLL_REMOVE after
closing the socket, and sometimes, it uses
CURL_POLL_REMOVE just to move the (still open)
connection to the pool; in the first case,
Abandon() would be most appropriate, but it breaks
the second case - is that a CURL bug? is there a
better solution? */
}
/**
* Callback function for CURLMOPT_SOCKETFUNCTION.
*/
static int SocketFunction(CURL *easy,
curl_socket_t s, int action,
void *userp, void *socketp) noexcept;
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bool OnSocketReady(unsigned flags) noexcept override;
private:
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static constexpr int FlagsToCurlCSelect(unsigned flags) noexcept {
return (flags & (READ | HANGUP) ? CURL_CSELECT_IN : 0) |
(flags & WRITE ? CURL_CSELECT_OUT : 0) |
(flags & ERROR ? CURL_CSELECT_ERR : 0);
}
gcc_const
static unsigned CurlPollToFlags(int action) noexcept {
switch (action) {
case CURL_POLL_NONE:
return 0;
case CURL_POLL_IN:
return READ;
case CURL_POLL_OUT:
return WRITE;
case CURL_POLL_INOUT:
return READ|WRITE;
}
assert(false);
gcc_unreachable();
}
};
CurlGlobal::CurlGlobal(EventLoop &_loop)
:defer_read_info(_loop, BIND_THIS_METHOD(ReadInfo)),
timeout_event(_loop, BIND_THIS_METHOD(OnTimeout))
{
multi.SetOption(CURLMOPT_SOCKETFUNCTION, CurlSocket::SocketFunction);
multi.SetOption(CURLMOPT_SOCKETDATA, this);
multi.SetOption(CURLMOPT_TIMERFUNCTION, TimerFunction);
multi.SetOption(CURLMOPT_TIMERDATA, this);
}
int
CurlSocket::SocketFunction(gcc_unused CURL *easy,
curl_socket_t s, int action,
void *userp, void *socketp) noexcept {
auto &global = *(CurlGlobal *)userp;
CurlSocket *cs = (CurlSocket *)socketp;
assert(global.GetEventLoop().IsInside());
if (action == CURL_POLL_REMOVE) {
delete cs;
return 0;
}
if (cs == nullptr) {
cs = new CurlSocket(global, global.GetEventLoop(),
SocketDescriptor(s));
global.Assign(s, *cs);
} else {
#ifdef USE_EPOLL
/* when using epoll, we need to unregister the socket
each time this callback is invoked, because older
CURL versions may omit the CURL_POLL_REMOVE call
when the socket has been closed and recreated with
the same file number (bug found in CURL 7.26, CURL
7.33 not affected); in that case, epoll refuses the
EPOLL_CTL_MOD because it does not know the new
socket yet */
cs->Cancel();
#endif
}
unsigned flags = CurlPollToFlags(action);
if (flags != 0)
cs->Schedule(flags);
return 0;
}
bool
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CurlSocket::OnSocketReady(unsigned flags) noexcept
{
assert(GetEventLoop().IsInside());
global.SocketAction(GetSocket().Get(), FlagsToCurlCSelect(flags));
return true;
}
/**
* Runs in the I/O thread. No lock needed.
*
* Throws std::runtime_error on error.
*/
void
CurlGlobal::Add(CURL *easy, CurlRequest &request)
{
assert(GetEventLoop().IsInside());
assert(easy != nullptr);
curl_easy_setopt(easy, CURLOPT_PRIVATE, &request);
CURLMcode mcode = curl_multi_add_handle(multi.Get(), easy);
if (mcode != CURLM_OK)
throw FormatRuntimeError("curl_multi_add_handle() failed: %s",
curl_multi_strerror(mcode));
InvalidateSockets();
}
void
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CurlGlobal::Remove(CURL *easy) noexcept
{
assert(GetEventLoop().IsInside());
assert(easy != nullptr);
curl_multi_remove_handle(multi.Get(), easy);
InvalidateSockets();
}
static CurlRequest *
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ToRequest(CURL *easy) noexcept
{
void *p;
CURLcode code = curl_easy_getinfo(easy, CURLINFO_PRIVATE, &p);
if (code != CURLE_OK)
return nullptr;
return (CurlRequest *)p;
}
/**
* Check for finished HTTP responses.
*
* Runs in the I/O thread. The caller must not hold locks.
*/
inline void
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CurlGlobal::ReadInfo() noexcept
{
assert(GetEventLoop().IsInside());
CURLMsg *msg;
int msgs_in_queue;
while ((msg = curl_multi_info_read(multi.Get(),
&msgs_in_queue)) != nullptr) {
if (msg->msg == CURLMSG_DONE) {
auto *request = ToRequest(msg->easy_handle);
if (request != nullptr)
request->Done(msg->data.result);
}
}
}
inline void
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CurlGlobal::UpdateTimeout(long timeout_ms) noexcept
{
if (timeout_ms < 0) {
timeout_event.Cancel();
return;
}
if (timeout_ms < 10)
/* CURL 7.21.1 likes to report "timeout=0", which
means we're running in a busy loop. Quite a bad
idea to waste so much CPU. Let's use a lower limit
of 10ms. */
timeout_ms = 10;
timeout_event.Schedule(std::chrono::milliseconds(timeout_ms));
}
int
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CurlGlobal::TimerFunction(gcc_unused CURLM *_global, long timeout_ms,
void *userp) noexcept
{
auto &global = *(CurlGlobal *)userp;
assert(_global == global.multi.Get());
global.UpdateTimeout(timeout_ms);
return 0;
}
void
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CurlGlobal::OnTimeout() noexcept
{
SocketAction(CURL_SOCKET_TIMEOUT, 0);
}
void
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CurlGlobal::SocketAction(curl_socket_t fd, int ev_bitmask) noexcept
{
int running_handles;
CURLMcode mcode = curl_multi_socket_action(multi.Get(), fd, ev_bitmask,
&running_handles);
if (mcode != CURLM_OK)
FormatError(curlm_domain,
"curl_multi_socket_action() failed: %s",
curl_multi_strerror(mcode));
defer_read_info.Schedule();
}