Some fixes to issues that could cause client hangs.
[cubemap] / server.cpp
index d6b5b5b8b783446ce08e87972b34430b9bf4e547..54e6b5e804d9959632b1ef70df6a53fee7f52fac 100644 (file)
 #include <vector>
 #include <string>
 #include <map>
+#include <algorithm>
 
 #include "metacube.h"
 #include "server.h"
 #include "mutexlock.h"
+#include "parse.h"
+#include "state.pb.h"
 
 using namespace std;
 
+Client::Client(int sock)
+       : sock(sock),
+         state(Client::READING_REQUEST),
+         stream(NULL),
+         header_or_error_bytes_sent(0),
+         bytes_sent(0)
+{
+       request.reserve(1024);
+}
+       
+Client::Client(const ClientProto &serialized, Stream *stream)
+       : sock(serialized.sock()),
+         state(State(serialized.state())),
+         request(serialized.request()),
+         stream_id(serialized.stream_id()),
+         stream(stream),
+         header_or_error(serialized.header_or_error()),
+         header_or_error_bytes_sent(serialized.header_or_error_bytes_sent()),
+         bytes_sent(serialized.bytes_sent())
+{
+}
+
+ClientProto Client::serialize() const
+{
+       ClientProto serialized;
+       serialized.set_sock(sock);
+       serialized.set_state(state);
+       serialized.set_request(request);
+       serialized.set_stream_id(stream_id);
+       serialized.set_header_or_error(header_or_error);
+       serialized.set_header_or_error_bytes_sent(serialized.header_or_error_bytes_sent());
+       serialized.set_bytes_sent(bytes_sent);
+       return serialized;
+}
+
+Stream::Stream(const string &stream_id)
+       : stream_id(stream_id),
+         data(new char[BACKLOG_SIZE]),
+         data_size(0)
+{
+       memset(data, 0, BACKLOG_SIZE);
+}
+
+Stream::~Stream()
+{
+       delete[] data;
+}
+
+Stream::Stream(const StreamProto &serialized)
+       : stream_id(serialized.stream_id()),
+         header(serialized.header()),
+         data(new char[BACKLOG_SIZE]),
+         data_size(serialized.data_size())
+{
+       assert(serialized.data().size() == BACKLOG_SIZE);
+       memcpy(data, serialized.data().data(), BACKLOG_SIZE);
+}
+
+StreamProto Stream::serialize() const
+{
+       StreamProto serialized;
+       serialized.set_header(header);
+       serialized.set_data(string(data, data + BACKLOG_SIZE));
+       serialized.set_data_size(data_size);
+       serialized.set_stream_id(stream_id);
+       return serialized;
+}
+
 Server::Server()
 {
        pthread_mutex_init(&mutex, NULL);
@@ -31,10 +102,40 @@ Server::Server()
        }
 }
 
+Server::~Server()
+{
+       int ret;
+       do {
+               ret = close(epoll_fd);
+       } while (ret == -1 && errno == EINTR);
+
+       if (ret == -1) {
+               perror("close(epoll_fd)");
+       }
+}
+
 void Server::run()
 {
-       pthread_t thread;
-       pthread_create(&thread, NULL, Server::do_work_thunk, this);
+       should_stop = false;
+       
+       // Joinable is already the default, but it's good to be certain.
+       pthread_attr_t attr;
+       pthread_attr_init(&attr);
+       pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
+       pthread_create(&worker_thread, &attr, Server::do_work_thunk, this);
+}
+       
+void Server::stop()
+{
+       {
+               MutexLock lock(&mutex);
+               should_stop = true;
+       }
+
+       if (pthread_join(worker_thread, NULL) == -1) {
+               perror("pthread_join");
+               exit(1);
+       }
 }
 
 void *Server::do_work_thunk(void *arg)
@@ -48,13 +149,20 @@ void Server::do_work()
 {
        for ( ;; ) {
                int nfds = epoll_wait(epoll_fd, events, EPOLL_MAX_EVENTS, EPOLL_TIMEOUT_MS);
-
-               MutexLock lock(&mutex);  // We release the mutex between iterations.
+               if (nfds == -1 && errno == EINTR) {
+                       continue;
+               }
                if (nfds == -1) {
                        perror("epoll_wait");
                        exit(1);
                }
-               
+
+               MutexLock lock(&mutex);  // We release the mutex between iterations.
+       
+               if (should_stop) {
+                       return;
+               }
+       
                for (int i = 0; i < nfds; ++i) {
                        int fd = events[i].data.fd;
                        assert(clients.count(fd) != 0);
@@ -69,69 +177,148 @@ void Server::do_work()
                }
        }
 }
-       
+
+CubemapStateProto Server::serialize() const
+{
+       CubemapStateProto serialized;
+       for (map<int, Client>::const_iterator client_it = clients.begin();
+            client_it != clients.end();
+            ++client_it) {
+               serialized.add_clients()->MergeFrom(client_it->second.serialize());
+       }
+       for (map<string, Stream *>::const_iterator stream_it = streams.begin();
+            stream_it != streams.end();
+            ++stream_it) {
+               serialized.add_streams()->MergeFrom(stream_it->second->serialize());
+       }
+       return serialized;
+}
+
 void Server::add_client(int sock)
 {
        MutexLock lock(&mutex);
-       Client new_client;
-       new_client.sock = sock;
-       new_client.client_request.reserve(1024);
-       new_client.state = Client::READING_REQUEST;
-       new_client.header_bytes_sent = 0;
-       new_client.bytes_sent = 0;
-
-       clients.insert(make_pair(sock, new_client));
+       clients.insert(make_pair(sock, Client(sock)));
 
        // Start listening on data from this socket.
        epoll_event ev;
        ev.events = EPOLLIN | EPOLLRDHUP;
+       ev.data.u64 = 0;  // Keep Valgrind happy.
        ev.data.fd = sock;
        if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sock, &ev) == -1) {
                perror("epoll_ctl(EPOLL_CTL_ADD)");
                exit(1);
        }
 }
-       
+
+void Server::add_client_from_serialized(const ClientProto &client)
+{
+       MutexLock lock(&mutex);
+       Stream *stream = find_stream(client.stream_id());
+       clients.insert(make_pair(client.sock(), Client(client, stream)));
+
+       // Start listening on data from this socket.
+       epoll_event ev;
+       if (client.state() == Client::READING_REQUEST) {
+               ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
+       } else {
+               // If we don't have more data for this client, we'll be putting it into
+               // the sleeping array again soon.
+               ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
+       }
+       ev.data.u64 = 0;  // Keep Valgrind happy.
+       ev.data.fd = client.sock();
+       if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client.sock(), &ev) == -1) {
+               perror("epoll_ctl(EPOLL_CTL_ADD)");
+               exit(1);
+       }
+
+       process_client(&clients[client.sock()]);
+}
+
 void Server::add_stream(const string &stream_id)
 {
        MutexLock lock(&mutex);
-       streams.insert(make_pair(stream_id, Stream()));
+       streams.insert(make_pair(stream_id, new Stream(stream_id)));
+}
+
+void Server::add_stream_from_serialized(const StreamProto &stream)
+{
+       MutexLock lock(&mutex);
+       streams.insert(make_pair(stream.stream_id(), new Stream(stream)));
 }
        
 void Server::set_header(const string &stream_id, const string &header)
 {
        MutexLock lock(&mutex);
-       assert(streams.count(stream_id) != 0);
-       streams[stream_id].header = header;
+       find_stream(stream_id)->header = header;
+
+       // If there are clients we haven't sent anything to yet, we should give
+       // them the header, so push back into the SENDING_HEADER state.
+       for (map<int, Client>::iterator client_it = clients.begin();
+            client_it != clients.end();
+            ++client_it) {
+               Client *client = &client_it->second;
+               if (client->state == Client::SENDING_DATA &&
+                   client->bytes_sent == 0) {
+                       construct_header(client);
+               }
+       }
 }
        
 void Server::add_data(const string &stream_id, const char *data, size_t bytes)
 {
-       // TODO
+       if (bytes == 0) {
+               return;
+       }
+
+       MutexLock lock(&mutex);
+       Stream *stream = find_stream(stream_id);
+       size_t pos = stream->data_size % BACKLOG_SIZE;
+       stream->data_size += bytes;
+
+       if (pos + bytes > BACKLOG_SIZE) {
+               size_t to_copy = BACKLOG_SIZE - pos;
+               memcpy(stream->data + pos, data, to_copy);
+               data += to_copy;
+               bytes -= to_copy;
+               pos = 0;
+       }
+
+       memcpy(stream->data + pos, data, bytes);
+       wake_up_all_clients();
 }
-       
+
+// See the .h file for postconditions after this function.     
 void Server::process_client(Client *client)
 {
        switch (client->state) {
        case Client::READING_REQUEST: {
+read_request_again:
                // Try to read more of the request.
                char buf[1024];
-               int ret = read(client->sock, buf, sizeof(buf));
+               int ret;
+               do {
+                       ret = read(client->sock, buf, sizeof(buf));
+               } while (ret == -1 && errno == EINTR);
+
+               if (ret == -1 && errno == EAGAIN) {
+                       // No more data right now. Nothing to do.
+                       // This is postcondition #2.
+                       return;
+               }
                if (ret == -1) {
                        perror("read");
                        close_client(client);
                        return;
                }
                if (ret == 0) {
-                       // No data? This really means that we were triggered for something else than
-                       // POLLIN (which suggests a logic error in epoll).
-                       fprintf(stderr, "WARNING: fd %d returned unexpectedly 0 bytes!\n", client->sock);
+                       // OK, the socket is closed.
                        close_client(client);
                        return;
                }
 
                // Guard against overlong requests gobbling up all of our space.
-               if (client->client_request.size() + ret > MAX_CLIENT_REQUEST) {
+               if (client->request.size() + ret > MAX_CLIENT_REQUEST) {
                        fprintf(stderr, "WARNING: fd %d sent overlong request!\n", client->sock);
                        close_client(client);
                        return;
@@ -139,105 +326,208 @@ void Server::process_client(Client *client)
 
                // See if we have \r\n\r\n anywhere in the request. We start three bytes
                // before what we just appended, in case we just got the final character.
-               size_t existing_req_bytes = client->client_request.size();
-               client->client_request.append(string(buf, buf + ret));
+               size_t existing_req_bytes = client->request.size();
+               client->request.append(string(buf, buf + ret));
        
                size_t start_at = (existing_req_bytes >= 3 ? existing_req_bytes - 3 : 0);
                const char *ptr = reinterpret_cast<char *>(
-                       memmem(client->client_request.data() + start_at, client->client_request.size() - start_at,
+                       memmem(client->request.data() + start_at, client->request.size() - start_at,
                               "\r\n\r\n", 4));
                if (ptr == NULL) {
                        // OK, we don't have the entire header yet. Fine; we'll get it later.
-                       return;
+                       // See if there's more data for us.
+                       goto read_request_again;
                }
 
-               if (ptr != client->client_request.data() + client->client_request.size() - 4) {
+               if (ptr != client->request.data() + client->request.size() - 4) {
                        fprintf(stderr, "WARNING: fd %d had junk data after request!\n", client->sock);
                        close_client(client);
                        return;
                }
 
-               parse_request(client);
-               break;
+               int error_code = parse_request(client);
+               if (error_code == 200) {
+                       construct_header(client);
+               } else {
+                       construct_error(client, error_code);
+               }
+
+               // We've changed states, so fall through.
+               assert(client->state == Client::SENDING_ERROR ||
+                      client->state == Client::SENDING_HEADER);
        }
+       case Client::SENDING_ERROR:
        case Client::SENDING_HEADER: {
-               int ret = write(client->sock,
-                               client->header.data() + client->header_bytes_sent,
-                               client->header.size() - client->header_bytes_sent);
+sending_header_or_error_again:
+               int ret;
+               do {
+                       ret = write(client->sock,
+                                   client->header_or_error.data() + client->header_or_error_bytes_sent,
+                                   client->header_or_error.size() - client->header_or_error_bytes_sent);
+               } while (ret == -1 && errno == EINTR);
+
+               if (ret == -1 && errno == EAGAIN) {
+                       // We're out of socket space, so now we're at the “low edge” of epoll's
+                       // edge triggering. epoll will tell us when there is more room, so for now,
+                       // just return.
+                       // This is postcondition #4.
+                       return;
+               }
+
                if (ret == -1) {
+                       // Error! Postcondition #1.
                        perror("write");
                        close_client(client);
                        return;
                }
                
-               client->header_bytes_sent += ret;
-               assert(client->header_bytes_sent <= client->header.size());
+               client->header_or_error_bytes_sent += ret;
+               assert(client->header_or_error_bytes_sent <= client->header_or_error.size());
 
-               if (client->header_bytes_sent < client->header.size()) {
-                       // We haven't sent all yet. Fine; we'll do that later.
-                       return;
+               if (client->header_or_error_bytes_sent < client->header_or_error.size()) {
+                       // We haven't sent all yet. Fine; go another round.
+                       goto sending_header_or_error_again;
                }
 
-               // We're done sending the header! Clear the entire header to release some memory.
-               client->header.clear();
+               // We're done sending the header or error! Clear it to release some memory.
+               client->header_or_error.clear();
+
+               if (client->state == Client::SENDING_ERROR) {
+                       // We're done sending the error, so now close.  
+                       // This is postcondition #1.
+                       close_client(client);
+                       return;
+               }
 
                // Start sending from the end. In other words, we won't send any of the backlog,
                // but we'll start sending immediately as we get data.
+               // This is postcondition #3.
                client->state = Client::SENDING_DATA;
-               client->bytes_sent = streams[client->stream_id].data_size;
-               break;
+               client->bytes_sent = client->stream->data_size;
+               sleeping_clients.push_back(client);
+               return;
        }
        case Client::SENDING_DATA: {
                // See if there's some data we've lost. Ideally, we should drop to a block boundary,
                // but resync will be the mux's problem.
-               const Stream &stream = streams[client->stream_id];
-               size_t bytes_to_send = stream.data_size - client->bytes_sent;
+               const Stream *stream = client->stream;
+               size_t bytes_to_send = stream->data_size - client->bytes_sent;
                if (bytes_to_send > BACKLOG_SIZE) {
                        fprintf(stderr, "WARNING: fd %d lost %lld bytes, maybe too slow connection\n",
                                client->sock,
                                (long long int)(bytes_to_send - BACKLOG_SIZE));
-                       client->bytes_sent = streams[client->stream_id].data_size - BACKLOG_SIZE;
+                       client->bytes_sent = stream->data_size - BACKLOG_SIZE;
                        bytes_to_send = BACKLOG_SIZE;
                }
 
                // See if we need to split across the circular buffer.
-               int ret;
+               ssize_t ret;
                if ((client->bytes_sent % BACKLOG_SIZE) + bytes_to_send > BACKLOG_SIZE) {
-                       // TODO: writev
-                       assert(false);
+                       size_t bytes_first_part = BACKLOG_SIZE - (client->bytes_sent % BACKLOG_SIZE);
+
+                       iovec iov[2];
+                       iov[0].iov_base = const_cast<char *>(stream->data + (client->bytes_sent % BACKLOG_SIZE));
+                       iov[0].iov_len = bytes_first_part;
+
+                       iov[1].iov_base = const_cast<char *>(stream->data);
+                       iov[1].iov_len = bytes_to_send - bytes_first_part;
+
+                       do {
+                               ret = writev(client->sock, iov, 2);
+                       } while (ret == -1 && errno == EINTR);
                } else {
-                       ret = write(client->sock,
-                                   stream.data + (client->bytes_sent % BACKLOG_SIZE),
-                                   bytes_to_send);
+                       do {
+                               ret = write(client->sock,
+                                           stream->data + (client->bytes_sent % BACKLOG_SIZE),
+                                           bytes_to_send);
+                       } while (ret == -1 && errno == EINTR);
+               }
+               if (ret == -1 && errno == EAGAIN) {
+                       // We're out of socket space, so return; epoll will wake us up
+                       // when there is more room.
+                       // This is postcondition #4.
+                       return;
                }
                if (ret == -1) {
+                       // Error, close; postcondition #1.
                        perror("write/writev");
                        close_client(client);
                        return;
                }
-               client->bytes_sent += ret;      
+               client->bytes_sent += ret;
+
+               if (client->bytes_sent == stream->data_size) {
+                       // We don't have any more data for this client, so put it to sleep.
+                       // This is postcondition #3.
+                       put_client_to_sleep(client);
+               } else {
+                       // XXX: Do we need to go another round here to explicitly
+                       // get the EAGAIN?
+               }
                break;
        }
        default:
-               // TODO
                assert(false);
        }
 }
 
-void Server::parse_request(Client *client)
+int Server::parse_request(Client *client)
 {
-       // TODO: Actually parse the request. :-)
-       client->stream_id = "stream";
+       vector<string> lines = split_lines(client->request);
+       if (lines.empty()) {
+               return 400;  // Bad request (empty).
+       }
+
+       vector<string> request_tokens = split_tokens(lines[0]);
+       if (request_tokens.size() < 2) {
+               return 400;  // Bad request (empty).
+       }
+       if (request_tokens[0] != "GET") {
+               return 400;  // Should maybe be 405 instead?
+       }
+       if (streams.count(request_tokens[1]) == 0) {
+               return 404;  // Not found.
+       }
+
+       client->stream_id = request_tokens[1];
+       client->stream = find_stream(client->stream_id);
+       client->request.clear();
 
-       // Construct the header.
-       client->header = "HTTP/1.0 200 OK\r\nContent-type: todo/fixme\r\n\r\n" +
-               streams[client->stream_id].header;
+       return 200;  // OK!
+}
+
+void Server::construct_header(Client *client)
+{
+       client->header_or_error = "HTTP/1.0 200 OK\r\nContent-type: video/x-flv\r\nCache-Control: no-cache\r\n\r\n" +
+               find_stream(client->stream_id)->header;
 
        // Switch states.
        client->state = Client::SENDING_HEADER;
 
        epoll_event ev;
-       ev.events = EPOLLOUT | EPOLLRDHUP;
+       ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
+       ev.data.u64 = 0;  // Keep Valgrind happy.
+       ev.data.fd = client->sock;
+
+       if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
+               perror("epoll_ctl(EPOLL_CTL_MOD)");
+               exit(1);
+       }
+}
+       
+void Server::construct_error(Client *client, int error_code)
+{
+       char error[256];
+       snprintf(error, 256, "HTTP/1.0 %d Error\r\nContent-type: text/plain\r\n\r\nSomething went wrong. Sorry.\r\n",
+               error_code);
+       client->header_or_error = error;
+
+       // Switch states.
+       client->state = Client::SENDING_ERROR;
+
+       epoll_event ev;
+       ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
+       ev.data.u64 = 0;  // Keep Valgrind happy.
        ev.data.fd = client->sock;
 
        if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
@@ -252,8 +542,42 @@ void Server::close_client(Client *client)
                perror("epoll_ctl(EPOLL_CTL_DEL)");
                exit(1);
        }
+
+       // This client could be sleeping, so we'll need to fix that. (Argh, O(n).)
+       vector<Client *>::iterator new_end =
+               remove(sleeping_clients.begin(), sleeping_clients.end(), client);
+       sleeping_clients.erase(new_end, sleeping_clients.end());
        
        // Bye-bye!
-       close(client->sock);
+       int ret;
+       do {
+               ret = close(client->sock);
+       } while (ret == -1 && errno == EINTR);
+
+       if (ret == -1) {
+               perror("close");
+       }
+
        clients.erase(client->sock);
 }
+       
+void Server::put_client_to_sleep(Client *client)
+{
+       sleeping_clients.push_back(client);
+}
+
+void Server::wake_up_all_clients()
+{
+       vector<Client *> to_process;
+       swap(sleeping_clients, to_process);
+       for (unsigned i = 0; i < to_process.size(); ++i) {
+               process_client(to_process[i]);
+       }
+}
+       
+Stream *Server::find_stream(const string &stream_id)
+{
+       map<string, Stream *>::iterator it = streams.find(stream_id);
+       assert(it != streams.end());
+       return it->second;
+}