1 /* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
5 * Copyright (C) 2011 Data Differential, http://datadifferential.com/
6 * Copyright (C) 2006-2009 Brian Aker
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions are
13 * * Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
16 * * Redistributions in binary form must reproduce the above
17 * copyright notice, this list of conditions and the following disclaimer
18 * in the documentation and/or other materials provided with the
21 * * The names of its contributors may not be used to endorse or
22 * promote products derived from this software without specific prior
25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
26 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
27 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
28 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
29 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
35 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 #include <libmemcached/common.h>
42 enum memc_read_or_write
{
48 * Try to fill the input buffer for a server with as much
51 * @param ptr the server to pack
53 static bool repack_input_buffer(memcached_server_write_instance_st ptr
)
55 if (ptr
->read_ptr
!= ptr
->read_buffer
)
57 /* Move all of the data to the beginning of the buffer so
58 ** that we can fit more data into the buffer...
60 memmove(ptr
->read_buffer
, ptr
->read_ptr
, ptr
->read_buffer_length
);
61 ptr
->read_ptr
= ptr
->read_buffer
;
62 ptr
->read_data_length
= ptr
->read_buffer_length
;
65 /* There is room in the buffer, try to fill it! */
66 if (ptr
->read_buffer_length
!= MEMCACHED_MAX_BUFFER
)
69 /* Just try a single read to grab what's available */
70 ssize_t nr
= recv(ptr
->fd
,
71 ptr
->read_ptr
+ ptr
->read_data_length
,
72 MEMCACHED_MAX_BUFFER
- ptr
->read_data_length
,
79 switch (get_socket_errno())
88 #ifdef TARGET_OS_LINUX
91 break; // No IO is fine, we can just move on
94 memcached_set_errno(*ptr
, get_socket_errno(), MEMCACHED_AT
);
99 case 0: // Shutdown on the socket has occurred
101 memcached_set_error(*ptr
, MEMCACHED_CONNECTION_FAILURE
, MEMCACHED_AT
);
107 ptr
->read_data_length
+= size_t(nr
);
108 ptr
->read_buffer_length
+= size_t(nr
);
119 * If the we have callbacks connected to this server structure
120 * we may start process the input queue and fire the callbacks
121 * for the incomming messages. This function is _only_ called
122 * when the input buffer is full, so that we _know_ that we have
123 * at least _one_ message to process.
125 * @param ptr the server to star processing iput messages for
126 * @return true if we processed anything, false otherwise
128 static bool process_input_buffer(memcached_server_write_instance_st ptr
)
131 ** We might be able to process some of the response messages if we
132 ** have a callback set up
134 if (ptr
->root
->callbacks
!= NULL
)
137 * We might have responses... try to read them out and fire
140 memcached_callback_st cb
= *ptr
->root
->callbacks
;
142 memcached_set_processing_input((memcached_st
*)ptr
->root
, true);
144 char buffer
[MEMCACHED_DEFAULT_COMMAND_SIZE
];
145 memcached_return_t error
;
146 memcached_st
*root
= (memcached_st
*)ptr
->root
;
147 error
= memcached_response(ptr
, buffer
, sizeof(buffer
),
150 memcached_set_processing_input(root
, false);
152 if (error
== MEMCACHED_SUCCESS
)
154 for (unsigned int x
= 0; x
< cb
.number_of_callback
; x
++)
156 error
= (*cb
.callback
[x
])(ptr
->root
, &root
->result
, cb
.context
);
157 if (error
!= MEMCACHED_SUCCESS
)
161 /* @todo what should I do with the error message??? */
163 /* @todo what should I do with other error messages?? */
170 static memcached_return_t
io_wait(memcached_server_write_instance_st ptr
,
171 const memc_read_or_write read_or_write
)
177 if (read_or_write
== MEM_WRITE
) /* write */
180 WATCHPOINT_SET(ptr
->io_wait_count
.write
++);
184 WATCHPOINT_SET(ptr
->io_wait_count
.read
++);
188 ** We are going to block on write, but at least on Solaris we might block
189 ** on write if we haven't read anything from our input buffer..
190 ** Try to purge the input buffer if we don't do any flow control in the
191 ** application layer (just sending a lot of data etc)
192 ** The test is moved down in the purge function to avoid duplication of
195 if (read_or_write
== MEM_WRITE
)
197 memcached_return_t rc
= memcached_purge(ptr
);
198 if (rc
!= MEMCACHED_SUCCESS
&& rc
!= MEMCACHED_STORED
)
200 return MEMCACHED_FAILURE
;
204 if (ptr
->root
->poll_timeout
== 0) // Mimic 0 causes timeout behavior (not all platforms do this)
206 return memcached_set_error(*ptr
, MEMCACHED_TIMEOUT
, MEMCACHED_AT
);
210 while (--loop_max
) // While loop is for ERESTART or EINTR
213 int error
= poll(&fds
, 1, ptr
->root
->poll_timeout
);
217 WATCHPOINT_IF_LABELED_NUMBER(read_or_write
&& loop_max
< 4, "read() times we had to loop, decremented down from 5", loop_max
);
218 WATCHPOINT_IF_LABELED_NUMBER(!read_or_write
&& loop_max
< 4, "write() times we had to loop, decremented down from 5", loop_max
);
220 return MEMCACHED_SUCCESS
;
222 case 0: // Timeout occured, we let the while() loop do its thing.
223 return memcached_set_error(*ptr
, MEMCACHED_TIMEOUT
, MEMCACHED_AT
);
226 WATCHPOINT_ERRNO(get_socket_errno());
227 switch (get_socket_errno())
229 #ifdef TARGET_OS_LINUX
237 return memcached_set_error(*ptr
, MEMCACHED_MEMORY_ALLOCATION_FAILURE
, MEMCACHED_AT
);
240 return memcached_set_error(*ptr
, MEMCACHED_MEMORY_ALLOCATION_FAILURE
, MEMCACHED_AT
, memcached_literal_param("RLIMIT_NOFILE exceeded, or if OSX the timeout value was invalid"));
243 if (fds
.revents
& POLLERR
)
246 socklen_t len
= sizeof (err
);
247 if (getsockopt(ptr
->fd
, SOL_SOCKET
, SO_ERROR
, &err
, &len
) == 0)
258 memcached_set_errno(*ptr
, get_socket_errno(), MEMCACHED_AT
);
260 int local_errno
= get_socket_errno(); // We cache in case memcached_quit_server() modifies errno
261 memcached_quit_server(ptr
, true);
263 return memcached_set_errno(*ptr
, local_errno
, MEMCACHED_AT
);
268 memcached_quit_server(ptr
, true);
270 return memcached_set_errno(*ptr
, get_socket_errno(), MEMCACHED_AT
);
273 static bool io_flush(memcached_server_write_instance_st ptr
,
274 const bool with_flush
,
275 memcached_return_t
& error
)
278 ** We might want to purge the input buffer if we haven't consumed
279 ** any output yet... The test for the limits is the purge is inline
280 ** in the purge function to avoid duplicating the logic..
283 memcached_return_t rc
;
284 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
285 rc
= memcached_purge(ptr
);
287 if (rc
!= MEMCACHED_SUCCESS
&& rc
!= MEMCACHED_STORED
)
292 char *local_write_ptr
= ptr
->write_buffer
;
293 size_t write_length
= ptr
->write_buffer_offset
;
295 error
= MEMCACHED_SUCCESS
;
297 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
299 /* Looking for memory overflows */
301 if (write_length
== MEMCACHED_MAX_BUFFER
)
302 WATCHPOINT_ASSERT(ptr
->write_buffer
== local_write_ptr
);
303 WATCHPOINT_ASSERT((ptr
->write_buffer
+ MEMCACHED_MAX_BUFFER
) >= (local_write_ptr
+ write_length
));
308 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
309 WATCHPOINT_ASSERT(write_length
> 0);
311 ssize_t sent_length
= 0;
312 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
315 sent_length
= ::send(ptr
->fd
, local_write_ptr
, write_length
, MSG_NOSIGNAL
|MSG_DONTWAIT
);
319 sent_length
= ::send(ptr
->fd
, local_write_ptr
, write_length
, MSG_NOSIGNAL
|MSG_DONTWAIT
|MSG_MORE
);
322 if (sent_length
== SOCKET_ERROR
)
324 memcached_set_errno(*ptr
, get_socket_errno(), MEMCACHED_AT
);
325 #if 0 // @todo I should look at why we hit this bit of code hard frequently
326 WATCHPOINT_ERRNO(get_socket_errno());
327 WATCHPOINT_NUMBER(get_socket_errno());
329 switch (get_socket_errno())
339 * We may be blocked on write because the input buffer
340 * is full. Let's check if we have room in our input
341 * buffer for more data and retry the write before
344 if (repack_input_buffer(ptr
) or process_input_buffer(ptr
))
349 memcached_return_t rc
= io_wait(ptr
, MEM_WRITE
);
350 if (memcached_success(rc
))
354 else if (rc
== MEMCACHED_TIMEOUT
)
356 error
= memcached_set_error(*ptr
, MEMCACHED_TIMEOUT
, MEMCACHED_AT
);
360 memcached_quit_server(ptr
, true);
361 error
= memcached_set_errno(*ptr
, get_socket_errno(), MEMCACHED_AT
);
367 memcached_quit_server(ptr
, true);
368 error
= memcached_set_errno(*ptr
, get_socket_errno(), MEMCACHED_AT
);
369 WATCHPOINT_ASSERT(ptr
->fd
== INVALID_SOCKET
);
374 ptr
->io_bytes_sent
+= uint32_t(sent_length
);
376 local_write_ptr
+= sent_length
;
377 write_length
-= uint32_t(sent_length
);
380 WATCHPOINT_ASSERT(write_length
== 0);
381 if (memcached_is_udp(ptr
->root
))
383 ptr
->write_buffer_offset
= UDP_DATAGRAM_HEADER_LENGTH
;
387 ptr
->write_buffer_offset
= 0;
393 memcached_return_t
memcached_io_wait_for_write(memcached_server_write_instance_st ptr
)
395 return io_wait(ptr
, MEM_WRITE
);
398 memcached_return_t
memcached_io_read(memcached_server_write_instance_st ptr
,
399 void *buffer
, size_t length
, ssize_t
& nread
)
401 assert(memcached_is_udp(ptr
->root
) == false);
402 assert_msg(ptr
, "Programmer error, memcached_io_read() recieved an invalid memcached_server_write_instance_st"); // Programmer error
403 char *buffer_ptr
= static_cast<char *>(buffer
);
405 if (ptr
->fd
== INVALID_SOCKET
)
408 assert_msg(int(ptr
->state
) <= int(MEMCACHED_SERVER_STATE_ADDRINFO
), "Programmer error, invalid socket state");
410 return MEMCACHED_CONNECTION_FAILURE
;
415 if (not ptr
->read_buffer_length
)
420 data_read
= ::recv(ptr
->fd
, ptr
->read_buffer
, MEMCACHED_MAX_BUFFER
, MSG_DONTWAIT
);
421 if (data_read
== SOCKET_ERROR
)
423 switch (get_socket_errno())
425 case EINTR
: // We just retry
428 case ETIMEDOUT
: // OSX
433 #ifdef TARGET_OS_LINUX
436 if (memcached_success(io_wait(ptr
, MEM_READ
)))
440 return MEMCACHED_IN_PROGRESS
;
444 case ENOTCONN
: // Programmer Error
445 WATCHPOINT_ASSERT(0);
447 WATCHPOINT_ASSERT(0);
449 assert_msg(ptr
->fd
!= INVALID_SOCKET
, "Programmer error, invalid socket");
455 memcached_quit_server(ptr
, true);
457 return memcached_set_errno(*ptr
, get_socket_errno(), MEMCACHED_AT
);
461 else if (data_read
== 0)
464 EOF. Any data received so far is incomplete
465 so discard it. This always reads by byte in case of TCP
466 and protocol enforcement happens at memcached_response()
467 looking for '\n'. We do not care for UDB which requests 8 bytes
468 at once. Generally, this means that connection went away. Since
469 for blocking I/O we do not return 0 and for non-blocking case
470 it will return EGAIN if data is not immediatly available.
472 WATCHPOINT_STRING("We had a zero length recv()");
473 memcached_quit_server(ptr
, true);
475 return memcached_set_error(*ptr
, MEMCACHED_CONNECTION_FAILURE
, MEMCACHED_AT
,
476 memcached_literal_param("::rec() returned zero, server has disconnected"));
478 } while (data_read
<= 0);
480 ptr
->io_bytes_sent
= 0;
481 ptr
->read_data_length
= (size_t) data_read
;
482 ptr
->read_buffer_length
= (size_t) data_read
;
483 ptr
->read_ptr
= ptr
->read_buffer
;
490 difference
= (length
> ptr
->read_buffer_length
) ? ptr
->read_buffer_length
: length
;
492 memcpy(buffer_ptr
, ptr
->read_ptr
, difference
);
493 length
-= difference
;
494 ptr
->read_ptr
+= difference
;
495 ptr
->read_buffer_length
-= difference
;
496 buffer_ptr
+= difference
;
500 *buffer_ptr
= *ptr
->read_ptr
;
502 ptr
->read_buffer_length
--;
508 nread
= ssize_t(buffer_ptr
- (char*)buffer
);
510 return MEMCACHED_SUCCESS
;
513 memcached_return_t
memcached_io_slurp(memcached_server_write_instance_st ptr
)
515 assert_msg(ptr
, "Programmer error, invalid memcached_server_write_instance_st");
516 assert(memcached_is_udp(ptr
->root
) == false);
518 if (ptr
->fd
== INVALID_SOCKET
)
520 assert_msg(int(ptr
->state
) <= int(MEMCACHED_SERVER_STATE_ADDRINFO
), "Invalid socket state");
521 return MEMCACHED_CONNECTION_FAILURE
;
525 char buffer
[MEMCACHED_MAX_BUFFER
];
528 data_read
= recv(ptr
->fd
, ptr
->read_buffer
, sizeof(buffer
), MSG_DONTWAIT
);
529 if (data_read
== SOCKET_ERROR
)
531 switch (get_socket_errno())
533 case EINTR
: // We just retry
536 case ETIMEDOUT
: // OSX
541 #ifdef TARGET_OS_LINUX
544 if (memcached_success(io_wait(ptr
, MEM_READ
)))
548 return MEMCACHED_IN_PROGRESS
;
552 case ENOTCONN
: // Programmer Error
553 WATCHPOINT_ASSERT(0);
555 WATCHPOINT_ASSERT(0);
557 assert_msg(ptr
->fd
!= INVALID_SOCKET
, "Invalid socket state");
562 return MEMCACHED_CONNECTION_FAILURE
; // We want this!
565 } while (data_read
> 0);
567 return MEMCACHED_CONNECTION_FAILURE
;
570 static ssize_t
_io_write(memcached_server_write_instance_st ptr
,
571 const void *buffer
, size_t length
, bool with_flush
)
573 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
574 assert(memcached_is_udp(ptr
->root
) == false);
576 size_t original_length
= length
;
577 const char *buffer_ptr
= static_cast<const char *>(buffer
);
585 if (memcached_is_udp(ptr
->root
))
587 //UDP does not support partial writes
588 buffer_end
= MAX_UDP_DATAGRAM_LENGTH
;
589 should_write
= length
;
590 if (ptr
->write_buffer_offset
+ should_write
> buffer_end
)
597 buffer_end
= MEMCACHED_MAX_BUFFER
;
598 should_write
= buffer_end
- ptr
->write_buffer_offset
;
599 should_write
= (should_write
< length
) ? should_write
: length
;
602 write_ptr
= ptr
->write_buffer
+ ptr
->write_buffer_offset
;
603 memcpy(write_ptr
, buffer_ptr
, should_write
);
604 ptr
->write_buffer_offset
+= should_write
;
605 buffer_ptr
+= should_write
;
606 length
-= should_write
;
608 if (ptr
->write_buffer_offset
== buffer_end
and memcached_is_udp(ptr
->root
) == false)
610 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
612 memcached_return_t rc
;
613 if (io_flush(ptr
, with_flush
, rc
) == false)
622 memcached_return_t rc
;
623 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
624 if (io_flush(ptr
, with_flush
, rc
) == false)
630 return (ssize_t
) original_length
;
633 bool memcached_io_write(memcached_server_write_instance_st ptr
)
635 return (_io_write(ptr
, NULL
, 0, true) >= 0);
638 ssize_t
memcached_io_write(memcached_server_write_instance_st ptr
,
639 const void *buffer
, const size_t length
, const bool with_flush
)
641 return _io_write(ptr
, buffer
, length
, with_flush
);
644 ssize_t
memcached_io_writev(memcached_server_write_instance_st ptr
,
645 libmemcached_io_vector_st vector
[],
646 const size_t number_of
, const bool with_flush
)
650 for (size_t x
= 0; x
< number_of
; x
++, vector
++)
656 if ((returnable
= _io_write(ptr
, vector
->buffer
, vector
->length
, false)) == -1)
666 if (memcached_io_write(ptr
) == false)
676 void memcached_io_close(memcached_server_write_instance_st ptr
)
678 if (ptr
->fd
== INVALID_SOCKET
)
683 /* in case of death shutdown to avoid blocking at close() */
684 if (shutdown(ptr
->fd
, SHUT_RDWR
) == SOCKET_ERROR
&& get_socket_errno() != ENOTCONN
)
686 WATCHPOINT_NUMBER(ptr
->fd
);
687 WATCHPOINT_ERRNO(get_socket_errno());
688 WATCHPOINT_ASSERT(get_socket_errno());
691 if (closesocket(ptr
->fd
) == SOCKET_ERROR
)
693 WATCHPOINT_ERRNO(get_socket_errno());
695 ptr
->state
= MEMCACHED_SERVER_STATE_NEW
;
696 ptr
->fd
= INVALID_SOCKET
;
699 memcached_server_write_instance_st
memcached_io_get_readable_server(memcached_st
*memc
)
701 #define MAX_SERVERS_TO_POLL 100
702 struct pollfd fds
[MAX_SERVERS_TO_POLL
];
703 unsigned int host_index
= 0;
705 for (uint32_t x
= 0; x
< memcached_server_count(memc
) && host_index
< MAX_SERVERS_TO_POLL
; ++x
)
707 memcached_server_write_instance_st instance
= memcached_server_instance_fetch(memc
, x
);
709 if (instance
->read_buffer_length
> 0) /* I have data in the buffer */
714 if (memcached_server_response_count(instance
) > 0)
716 fds
[host_index
].events
= POLLIN
;
717 fds
[host_index
].revents
= 0;
718 fds
[host_index
].fd
= instance
->fd
;
725 /* We have 0 or 1 server with pending events.. */
726 for (uint32_t x
= 0; x
< memcached_server_count(memc
); ++x
)
728 memcached_server_write_instance_st instance
=
729 memcached_server_instance_fetch(memc
, x
);
731 if (memcached_server_response_count(instance
) > 0)
740 int error
= poll(fds
, host_index
, memc
->poll_timeout
);
744 memcached_set_errno(*memc
, get_socket_errno(), MEMCACHED_AT
);
750 for (size_t x
= 0; x
< host_index
; ++x
)
752 if (fds
[x
].revents
& POLLIN
)
754 for (uint32_t y
= 0; y
< memcached_server_count(memc
); ++y
)
756 memcached_server_write_instance_st instance
=
757 memcached_server_instance_fetch(memc
, y
);
759 if (instance
->fd
== fds
[x
].fd
)
770 Eventually we will just kill off the server with the problem.
772 void memcached_io_reset(memcached_server_write_instance_st ptr
)
774 memcached_quit_server(ptr
, true);
778 * Read a given number of bytes from the server and place it into a specific
779 * buffer. Reset the IO channel on this server if an error occurs.
781 memcached_return_t
memcached_safe_read(memcached_server_write_instance_st ptr
,
786 char *data
= static_cast<char *>(dta
);
788 while (offset
< size
)
791 memcached_return_t rc
;
793 while (memcached_continue(rc
= memcached_io_read(ptr
, data
+ offset
, size
- offset
, nread
))) { };
795 if (memcached_failed(rc
))
800 offset
+= size_t(nread
);
803 return MEMCACHED_SUCCESS
;
806 memcached_return_t
memcached_io_readline(memcached_server_write_instance_st ptr
,
812 bool line_complete
= false;
814 while (line_complete
== false)
816 if (ptr
->read_buffer_length
== 0)
819 * We don't have any data in the buffer, so let's fill the read
820 * buffer. Call the standard read function to avoid duplicating
824 memcached_return_t rc
= memcached_io_read(ptr
, buffer_ptr
, 1, nread
);
825 if (memcached_failed(rc
) and rc
== MEMCACHED_IN_PROGRESS
)
827 memcached_quit_server(ptr
, true);
828 return memcached_set_error(*ptr
, rc
, MEMCACHED_AT
);
830 else if (memcached_failed(rc
))
835 if (*buffer_ptr
== '\n')
844 /* Now let's look in the buffer and copy as we go! */
845 while (ptr
->read_buffer_length
&& total_nr
< size
&& !line_complete
)
847 *buffer_ptr
= *ptr
->read_ptr
;
848 if (*buffer_ptr
== '\n')
850 line_complete
= true;
852 --ptr
->read_buffer_length
;
858 if (total_nr
== size
)
860 return MEMCACHED_PROTOCOL_ERROR
;
864 return MEMCACHED_SUCCESS
;