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1 : // Copyright (c) 2012-2021 Made to Order Software Corp. All Rights Reserved
2 : //
3 : // https://snapwebsites.org/project/eventdispatcher
4 : // contact@m2osw.com
5 : //
6 : // This program is free software; you can redistribute it and/or modify
7 : // it under the terms of the GNU General Public License as published by
8 : // the Free Software Foundation; either version 2 of the License, or
9 : // (at your option) any later version.
10 : //
11 : // This program is distributed in the hope that it will be useful,
12 : // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 : // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 : // GNU General Public License for more details.
15 : //
16 : // You should have received a copy of the GNU General Public License
17 : // along with this program; if not, write to the Free Software
18 : // Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19 :
20 : /** \file
21 : * \brief Implementation of the Snap Communicator class.
22 : *
23 : * This class wraps the C poll() interface in a C++ object with many types
24 : * of objects:
25 : *
26 : * \li Server Connections; for software that want to offer a port to
27 : * which clients can connect to; the server will call accept()
28 : * once a new client connection is ready; this results in a
29 : * Server/Client connection object
30 : * \li Client Connections; for software that want to connect to
31 : * a server; these expect the IP address and port to connect to
32 : * \li Server/Client Connections; for the server when it accepts a new
33 : * connection; in this case the server gets a socket from accept()
34 : * and creates one of these objects to handle the connection
35 : *
36 : * Using the poll() function is the easiest and allows us to listen
37 : * on pretty much any number of sockets (on my server it is limited
38 : * at 16,768 and frankly over 1,000 we probably will start to have
39 : * real slowness issues on small VPN servers.)
40 : */
41 :
42 : // self
43 : //
44 : #include "eventdispatcher/tcp_server_client_buffer_connection.h"
45 :
46 : #include "eventdispatcher/utils.h"
47 :
48 :
49 : // snaplogger lib
50 : //
51 : #include <snaplogger/message.h>
52 :
53 :
54 : // C++ lib
55 : //
56 : #include <algorithm>
57 : #include <cstring>
58 :
59 :
60 : // last include
61 : //
62 : #include <snapdev/poison.h>
63 :
64 :
65 :
66 : namespace ed
67 : {
68 :
69 :
70 :
71 : /** \brief Initialize a client socket.
72 : *
73 : * The client socket gets initialized with the specified 'socket'
74 : * parameter.
75 : *
76 : * If you are a pure client (opposed to a client that was just accepted)
77 : * you may want to consider using the tcp_client_buffer_connection
78 : * instead. That gives you a way to open the socket from a set of address
79 : * and port definitions among other things.
80 : *
81 : * This initialization, so things work as expected in our environment,
82 : * the function marks the socket as non-blocking. This is important for
83 : * the reader and writer capabilities.
84 : *
85 : * \param[in] client The client to be used for reading and writing.
86 : */
87 0 : tcp_server_client_buffer_connection::tcp_server_client_buffer_connection(tcp_bio_client::pointer_t client)
88 0 : : tcp_server_client_connection(client)
89 : {
90 0 : non_blocking();
91 0 : }
92 :
93 :
94 : /** \brief Check whether this connection still has some input in its buffer.
95 : *
96 : * This function returns true if there is partial incoming data in this
97 : * object's buffer.
98 : *
99 : * \return true if some buffered input is waiting for completion.
100 : */
101 0 : bool tcp_server_client_buffer_connection::has_input() const
102 : {
103 0 : return !f_line.empty();
104 : }
105 :
106 :
107 :
108 : /** \brief Check whether this connection still has some output in its buffer.
109 : *
110 : * This function returns true if there is still some output in the client
111 : * buffer. Output is added by the write() function, which is called by
112 : * the send_message() function.
113 : *
114 : * \return true if some buffered output is waiting to be sent out.
115 : */
116 0 : bool tcp_server_client_buffer_connection::has_output() const
117 : {
118 0 : return !f_output.empty();
119 : }
120 :
121 :
122 :
123 : /** \brief Tells that this connection is a writer when we have data to write.
124 : *
125 : * This function checks to know whether there is data to be written to
126 : * this connection socket. If so then the function returns true. Otherwise
127 : * it just returns false.
128 : *
129 : * This happens whenever you called the write() function and our cache
130 : * is not empty yet.
131 : *
132 : * \return true if there is data to write to the socket, false otherwise.
133 : */
134 0 : bool tcp_server_client_buffer_connection::is_writer() const
135 : {
136 0 : return get_socket() != -1 && !f_output.empty();
137 : }
138 :
139 :
140 : /** \brief Write data to the connection.
141 : *
142 : * This function can be used to send data to this TCP/IP connection.
143 : * The data is bufferized and as soon as the connection can WRITE
144 : * to the socket, it will wake up and send the data. In other words,
145 : * we cannot just sleep and wait for an answer. The transfer will
146 : * be asynchronous.
147 : *
148 : * \todo
149 : * Determine whether we may end up with really large buffers that
150 : * grow for a long time. This function only inserts and the
151 : * process_signal() function only reads some of the bytes but it
152 : * does not reduce the size of the buffer until all the data was
153 : * sent.
154 : *
155 : * \param[in] data The pointer to the buffer of data to be sent.
156 : * \param[out] length The number of bytes to send.
157 : */
158 0 : ssize_t tcp_server_client_buffer_connection::write(void const * data, size_t const length)
159 : {
160 0 : if(get_socket() == -1)
161 : {
162 0 : errno = EBADF;
163 0 : return -1;
164 : }
165 :
166 0 : if(data != nullptr && length > 0)
167 : {
168 0 : char const * d(reinterpret_cast<char const *>(data));
169 0 : f_output.insert(f_output.end(), d, d + length);
170 0 : return length;
171 : }
172 :
173 0 : return 0;
174 : }
175 :
176 :
177 : /** \brief Read and process as much data as possible.
178 : *
179 : * This function reads as much incoming data as possible and processes
180 : * it.
181 : *
182 : * If the input includes a newline character ('\n') then this function
183 : * calls the process_line() callback which can further process that
184 : * line of data.
185 : *
186 : * \todo
187 : * Look into a way, if possible, to have a single instantiation since
188 : * as far as I know this code matches the one written in the
189 : * process_read() of the tcp_client_buffer_connection and
190 : * the pipe_buffer_connection classes.
191 : */
192 0 : void tcp_server_client_buffer_connection::process_read()
193 : {
194 : // we read one character at a time until we get a '\n'
195 : // since we have a non-blocking socket we can read as
196 : // much as possible and then check for a '\n' and keep
197 : // any extra data in a cache.
198 : //
199 0 : if(get_socket() != -1)
200 : {
201 0 : int count_lines(0);
202 0 : std::int64_t const date_limit(get_current_date() + get_processing_time_limit());
203 0 : std::vector<char> buffer;
204 0 : buffer.resize(1024);
205 : for(;;)
206 : {
207 0 : errno = 0;
208 0 : ssize_t const r(read(&buffer[0], buffer.size()));
209 0 : if(r > 0)
210 : {
211 0 : for(ssize_t position(0); position < r; )
212 : {
213 0 : std::vector<char>::const_iterator it(std::find(buffer.begin() + position, buffer.begin() + r, '\n'));
214 0 : if(it == buffer.begin() + r)
215 : {
216 : // no newline, just add the whole thing
217 0 : f_line += std::string(&buffer[position], r - position);
218 0 : break; // do not waste time, we know we are done
219 : }
220 :
221 : // retrieve the characters up to the newline
222 : // character and process the line
223 : //
224 0 : f_line += std::string(&buffer[position], it - buffer.begin() - position);
225 0 : process_line(f_line);
226 0 : ++count_lines;
227 :
228 : // done with that line
229 : //
230 0 : f_line.clear();
231 :
232 : // we had a newline, we may still have some data
233 : // in that buffer; (+1 to skip the '\n' itself)
234 : //
235 0 : position = it - buffer.begin() + 1;
236 : }
237 :
238 : // when we reach here all the data read in `buffer` is
239 : // now either fully processed or in f_line
240 : //
241 : // TODO: change the way this works so we can test the
242 : // limit after each process_line() call
243 : //
244 0 : if(count_lines >= get_event_limit()
245 0 : || get_current_date() >= date_limit)
246 : {
247 : // we reach one or both limits, stop processing so
248 : // the other events have a chance to run
249 : //
250 0 : break;
251 : }
252 : }
253 0 : else if(r == 0 || errno == 0 || errno == EAGAIN || errno == EWOULDBLOCK)
254 : {
255 : // no more data available at this time
256 : break;
257 : }
258 : else //if(r < 0)
259 : {
260 0 : int const e(errno);
261 0 : SNAP_LOG_WARNING
262 0 : << "an error occurred while reading from socket (errno: "
263 : << e
264 : << " -- "
265 0 : << strerror(e)
266 : << ")."
267 : << SNAP_LOG_SEND;
268 0 : process_error();
269 0 : return;
270 : }
271 0 : }
272 : }
273 :
274 : // process next level too
275 0 : tcp_server_client_connection::process_read();
276 : }
277 :
278 :
279 : /** \brief Write to the connection's socket.
280 : *
281 : * This function implementation writes as much data as possible to the
282 : * connection's socket.
283 : *
284 : * This function calls the process_empty_buffer() callback whenever the
285 : * output buffer goes empty.
286 : */
287 0 : void tcp_server_client_buffer_connection::process_write()
288 : {
289 0 : if(get_socket() != -1)
290 : {
291 0 : errno = 0;
292 0 : ssize_t const r(tcp_server_client_connection::write(&f_output[f_position], f_output.size() - f_position));
293 0 : if(r > 0)
294 : {
295 : // some data was written
296 0 : f_position += r;
297 0 : if(f_position >= f_output.size())
298 : {
299 0 : f_output.clear();
300 0 : f_position = 0;
301 0 : process_empty_buffer();
302 : }
303 : }
304 0 : else if(r != 0 && errno != 0 && errno != EAGAIN && errno != EWOULDBLOCK)
305 : {
306 : // connection is considered bad, get rid of it
307 : //
308 0 : int const e(errno);
309 0 : SNAP_LOG_ERROR
310 0 : << "an error occurred while writing to socket of \""
311 0 : << get_name()
312 0 : << "\" (errno: "
313 : << e
314 : << " -- "
315 0 : << strerror(e)
316 : << ")."
317 : << SNAP_LOG_SEND;
318 0 : process_error();
319 0 : return;
320 : }
321 : }
322 :
323 : // process next level too
324 0 : tcp_server_client_connection::process_write();
325 : }
326 :
327 :
328 : /** \brief The remote hanged up.
329 : *
330 : * This function makes sure that the local connection gets closed properly.
331 : */
332 0 : void tcp_server_client_buffer_connection::process_hup()
333 : {
334 : // this connection is dead...
335 : //
336 0 : close();
337 :
338 0 : tcp_server_client_connection::process_hup();
339 0 : }
340 :
341 :
342 :
343 6 : } // namespace ed
344 : // vim: ts=4 sw=4 et
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