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())
84 #if EWOULDBLOCK != EAGAIN
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_st
*root
= (memcached_st
*)ptr
->root
;
146 memcached_return_t error
= memcached_response(ptr
, buffer
, sizeof(buffer
), &root
->result
);
148 memcached_set_processing_input(root
, false);
150 if (error
== MEMCACHED_SUCCESS
)
152 for (unsigned int x
= 0; x
< cb
.number_of_callback
; x
++)
154 error
= (*cb
.callback
[x
])(ptr
->root
, &root
->result
, cb
.context
);
155 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
)
174 ** We are going to block on write, but at least on Solaris we might block
175 ** on write if we haven't read anything from our input buffer..
176 ** Try to purge the input buffer if we don't do any flow control in the
177 ** application layer (just sending a lot of data etc)
178 ** The test is moved down in the purge function to avoid duplication of
181 if (read_or_write
== MEM_WRITE
)
183 if (memcached_fatal(memcached_purge(ptr
)))
185 return MEMCACHED_FAILURE
;
190 memset(&fds
, 0, sizeof(pollfd
));
194 if (read_or_write
== MEM_WRITE
) /* write */
197 ptr
->io_wait_count
.write
++;
201 ptr
->io_wait_count
.read
++;
204 if (ptr
->root
->poll_timeout
== 0) // Mimic 0 causes timeout behavior (not all platforms do this)
206 ptr
->io_wait_count
.timeouts
++;
207 return memcached_set_error(*ptr
, MEMCACHED_TIMEOUT
, MEMCACHED_AT
);
212 while (--loop_max
) // While loop is for ERESTART or EINTR
214 int active_fd
= poll(&fds
, 1, ptr
->root
->poll_timeout
);
218 assert_msg(active_fd
== 1 , "poll() returned an unexpected value");
219 return MEMCACHED_SUCCESS
;
221 else if (active_fd
== 0)
223 ptr
->io_wait_count
.timeouts
++;
224 return memcached_set_error(*ptr
, MEMCACHED_TIMEOUT
, MEMCACHED_AT
);
227 // Only an error should result in this code being called.
228 local_errno
= get_socket_errno(); // We cache in case memcached_quit_server() modifies errno
229 assert_msg(active_fd
== -1 , "poll() returned an unexpected value");
232 #ifdef TARGET_OS_LINUX
240 return memcached_set_error(*ptr
, MEMCACHED_MEMORY_ALLOCATION_FAILURE
, MEMCACHED_AT
);
243 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"));
246 if (fds
.revents
& POLLERR
)
249 socklen_t len
= sizeof (err
);
250 if (getsockopt(ptr
->fd
, SOL_SOCKET
, SO_ERROR
, &err
, &len
) == 0)
252 if (err
== 0) // treat this as EINTR
262 break; // should only occur from poll error
265 memcached_quit_server(ptr
, true);
267 return memcached_set_errno(*ptr
, local_errno
, MEMCACHED_AT
);
270 static bool io_flush(memcached_server_write_instance_st ptr
,
271 const bool with_flush
,
272 memcached_return_t
& error
)
275 ** We might want to purge the input buffer if we haven't consumed
276 ** any output yet... The test for the limits is the purge is inline
277 ** in the purge function to avoid duplicating the logic..
280 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
281 memcached_return_t rc
= memcached_purge(ptr
);
283 if (rc
!= MEMCACHED_SUCCESS
and rc
!= MEMCACHED_STORED
)
288 char *local_write_ptr
= ptr
->write_buffer
;
289 size_t write_length
= ptr
->write_buffer_offset
;
291 error
= MEMCACHED_SUCCESS
;
293 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
295 /* Looking for memory overflows */
297 if (write_length
== MEMCACHED_MAX_BUFFER
)
298 WATCHPOINT_ASSERT(ptr
->write_buffer
== local_write_ptr
);
299 WATCHPOINT_ASSERT((ptr
->write_buffer
+ MEMCACHED_MAX_BUFFER
) >= (local_write_ptr
+ write_length
));
304 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
305 WATCHPOINT_ASSERT(write_length
> 0);
307 int flags
= with_flush
? MSG_NOSIGNAL
|MSG_DONTWAIT
: MSG_NOSIGNAL
|MSG_DONTWAIT
|MSG_MORE
;
308 ssize_t sent_length
= ::send(ptr
->fd
, local_write_ptr
, write_length
, flags
);
310 if (sent_length
== SOCKET_ERROR
)
312 #if 0 // @todo I should look at why we hit this bit of code hard frequently
313 WATCHPOINT_ERRNO(get_socket_errno());
314 WATCHPOINT_NUMBER(get_socket_errno());
316 switch (get_socket_errno())
321 #if EWOULDBLOCK != EAGAIN
327 * We may be blocked on write because the input buffer
328 * is full. Let's check if we have room in our input
329 * buffer for more data and retry the write before
332 if (repack_input_buffer(ptr
) or process_input_buffer(ptr
))
337 memcached_return_t rc
= io_wait(ptr
, MEM_WRITE
);
338 if (memcached_success(rc
))
342 else if (rc
== MEMCACHED_TIMEOUT
)
347 memcached_quit_server(ptr
, true);
348 error
= memcached_set_errno(*ptr
, get_socket_errno(), MEMCACHED_AT
);
354 memcached_quit_server(ptr
, true);
355 error
= memcached_set_errno(*ptr
, get_socket_errno(), MEMCACHED_AT
);
356 WATCHPOINT_ASSERT(ptr
->fd
== INVALID_SOCKET
);
361 ptr
->io_bytes_sent
+= uint32_t(sent_length
);
363 local_write_ptr
+= sent_length
;
364 write_length
-= uint32_t(sent_length
);
367 WATCHPOINT_ASSERT(write_length
== 0);
368 ptr
->write_buffer_offset
= 0;
373 memcached_return_t
memcached_io_wait_for_write(memcached_server_write_instance_st ptr
)
375 return io_wait(ptr
, MEM_WRITE
);
378 memcached_return_t
memcached_io_read(memcached_server_write_instance_st ptr
,
379 void *buffer
, size_t length
, ssize_t
& nread
)
381 assert(memcached_is_udp(ptr
->root
) == false);
382 assert_msg(ptr
, "Programmer error, memcached_io_read() recieved an invalid memcached_server_write_instance_st"); // Programmer error
383 char *buffer_ptr
= static_cast<char *>(buffer
);
385 if (ptr
->fd
== INVALID_SOCKET
)
388 assert_msg(int(ptr
->state
) <= int(MEMCACHED_SERVER_STATE_ADDRINFO
), "Programmer error, invalid socket state");
390 return MEMCACHED_CONNECTION_FAILURE
;
395 if (ptr
->read_buffer_length
== 0)
400 data_read
= ::recv(ptr
->fd
, ptr
->read_buffer
, MEMCACHED_MAX_BUFFER
, MSG_DONTWAIT
);
401 if (data_read
== SOCKET_ERROR
)
403 switch (get_socket_errno())
405 case EINTR
: // We just retry
408 case ETIMEDOUT
: // OSX
409 #if EWOULDBLOCK != EAGAIN
413 #ifdef TARGET_OS_LINUX
417 memcached_return_t io_wait_ret
;
418 if (memcached_success(io_wait_ret
= io_wait(ptr
, MEM_READ
)))
428 case ENOTCONN
: // Programmer Error
429 WATCHPOINT_ASSERT(0);
431 WATCHPOINT_ASSERT(0);
433 assert_msg(ptr
->fd
!= INVALID_SOCKET
, "Programmer error, invalid socket");
439 memcached_quit_server(ptr
, true);
441 return memcached_set_errno(*ptr
, get_socket_errno(), MEMCACHED_AT
);
445 else if (data_read
== 0)
448 EOF. Any data received so far is incomplete
449 so discard it. This always reads by byte in case of TCP
450 and protocol enforcement happens at memcached_response()
451 looking for '\n'. We do not care for UDB which requests 8 bytes
452 at once. Generally, this means that connection went away. Since
453 for blocking I/O we do not return 0 and for non-blocking case
454 it will return EGAIN if data is not immediatly available.
456 WATCHPOINT_STRING("We had a zero length recv()");
457 memcached_quit_server(ptr
, true);
459 return memcached_set_error(*ptr
, MEMCACHED_CONNECTION_FAILURE
, MEMCACHED_AT
,
460 memcached_literal_param("::rec() returned zero, server has disconnected"));
462 } while (data_read
<= 0);
464 ptr
->io_bytes_sent
= 0;
465 ptr
->read_data_length
= (size_t) data_read
;
466 ptr
->read_buffer_length
= (size_t) data_read
;
467 ptr
->read_ptr
= ptr
->read_buffer
;
474 difference
= (length
> ptr
->read_buffer_length
) ? ptr
->read_buffer_length
: length
;
476 memcpy(buffer_ptr
, ptr
->read_ptr
, difference
);
477 length
-= difference
;
478 ptr
->read_ptr
+= difference
;
479 ptr
->read_buffer_length
-= difference
;
480 buffer_ptr
+= difference
;
484 *buffer_ptr
= *ptr
->read_ptr
;
486 ptr
->read_buffer_length
--;
492 nread
= ssize_t(buffer_ptr
- (char*)buffer
);
494 return MEMCACHED_SUCCESS
;
497 memcached_return_t
memcached_io_slurp(memcached_server_write_instance_st ptr
)
499 assert_msg(ptr
, "Programmer error, invalid memcached_server_write_instance_st");
500 assert(memcached_is_udp(ptr
->root
) == false);
502 if (ptr
->fd
== INVALID_SOCKET
)
504 assert_msg(int(ptr
->state
) <= int(MEMCACHED_SERVER_STATE_ADDRINFO
), "Invalid socket state");
505 return MEMCACHED_CONNECTION_FAILURE
;
509 char buffer
[MEMCACHED_MAX_BUFFER
];
512 data_read
= recv(ptr
->fd
, ptr
->read_buffer
, sizeof(buffer
), MSG_DONTWAIT
);
513 if (data_read
== SOCKET_ERROR
)
515 switch (get_socket_errno())
517 case EINTR
: // We just retry
520 case ETIMEDOUT
: // OSX
521 #if EWOULDBLOCK != EAGAIN
525 #ifdef TARGET_OS_LINUX
528 if (memcached_success(io_wait(ptr
, MEM_READ
)))
532 return MEMCACHED_IN_PROGRESS
;
536 case ENOTCONN
: // Programmer Error
537 WATCHPOINT_ASSERT(0);
539 WATCHPOINT_ASSERT(0);
541 assert_msg(ptr
->fd
!= INVALID_SOCKET
, "Invalid socket state");
546 return MEMCACHED_CONNECTION_FAILURE
; // We want this!
549 } while (data_read
> 0);
551 return MEMCACHED_CONNECTION_FAILURE
;
554 static ssize_t
_io_write(memcached_server_write_instance_st ptr
,
555 const void *buffer
, size_t length
, bool with_flush
)
557 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
558 assert(memcached_is_udp(ptr
->root
) == false);
560 size_t original_length
= length
;
561 const char *buffer_ptr
= static_cast<const char *>(buffer
);
566 size_t buffer_end
= MEMCACHED_MAX_BUFFER
;
567 size_t should_write
= buffer_end
-ptr
->write_buffer_offset
;
568 should_write
= (should_write
< length
) ? should_write
: length
;
570 write_ptr
= ptr
->write_buffer
+ ptr
->write_buffer_offset
;
571 memcpy(write_ptr
, buffer_ptr
, should_write
);
572 ptr
->write_buffer_offset
+= should_write
;
573 buffer_ptr
+= should_write
;
574 length
-= should_write
;
576 if (ptr
->write_buffer_offset
== buffer_end
)
578 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
580 memcached_return_t rc
;
581 if (io_flush(ptr
, with_flush
, rc
) == false)
590 memcached_return_t rc
;
591 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
592 if (io_flush(ptr
, with_flush
, rc
) == false)
598 return ssize_t(original_length
);
601 bool memcached_io_write(memcached_server_write_instance_st ptr
)
603 return (_io_write(ptr
, NULL
, 0, true) >= 0);
606 ssize_t
memcached_io_write(memcached_server_write_instance_st ptr
,
607 const void *buffer
, const size_t length
, const bool with_flush
)
609 return _io_write(ptr
, buffer
, length
, with_flush
);
612 ssize_t
memcached_io_writev(memcached_server_write_instance_st ptr
,
613 libmemcached_io_vector_st vector
[],
614 const size_t number_of
, const bool with_flush
)
618 for (size_t x
= 0; x
< number_of
; x
++, vector
++)
624 if ((returnable
= _io_write(ptr
, vector
->buffer
, vector
->length
, false)) == -1)
634 if (memcached_io_write(ptr
) == false)
644 void memcached_io_close(memcached_server_write_instance_st ptr
)
646 if (ptr
->fd
== INVALID_SOCKET
)
651 /* in case of death shutdown to avoid blocking at close() */
652 if (shutdown(ptr
->fd
, SHUT_RDWR
) == SOCKET_ERROR
&& get_socket_errno() != ENOTCONN
)
654 WATCHPOINT_NUMBER(ptr
->fd
);
655 WATCHPOINT_ERRNO(get_socket_errno());
656 WATCHPOINT_ASSERT(get_socket_errno());
659 if (closesocket(ptr
->fd
) == SOCKET_ERROR
)
661 WATCHPOINT_ERRNO(get_socket_errno());
663 ptr
->state
= MEMCACHED_SERVER_STATE_NEW
;
664 ptr
->fd
= INVALID_SOCKET
;
667 memcached_server_write_instance_st
memcached_io_get_readable_server(memcached_st
*memc
)
669 #define MAX_SERVERS_TO_POLL 100
670 struct pollfd fds
[MAX_SERVERS_TO_POLL
];
671 nfds_t host_index
= 0;
673 for (uint32_t x
= 0; x
< memcached_server_count(memc
) and host_index
< MAX_SERVERS_TO_POLL
; ++x
)
675 memcached_server_write_instance_st instance
= memcached_server_instance_fetch(memc
, x
);
677 if (instance
->read_buffer_length
> 0) /* I have data in the buffer */
682 if (memcached_server_response_count(instance
) > 0)
684 fds
[host_index
].events
= POLLIN
;
685 fds
[host_index
].revents
= 0;
686 fds
[host_index
].fd
= instance
->fd
;
693 /* We have 0 or 1 server with pending events.. */
694 for (uint32_t x
= 0; x
< memcached_server_count(memc
); ++x
)
696 memcached_server_write_instance_st instance
=
697 memcached_server_instance_fetch(memc
, x
);
699 if (memcached_server_response_count(instance
) > 0)
708 int error
= poll(fds
, host_index
, memc
->poll_timeout
);
712 memcached_set_errno(*memc
, get_socket_errno(), MEMCACHED_AT
);
718 for (nfds_t x
= 0; x
< host_index
; ++x
)
720 if (fds
[x
].revents
& POLLIN
)
722 for (uint32_t y
= 0; y
< memcached_server_count(memc
); ++y
)
724 memcached_server_write_instance_st instance
= memcached_server_instance_fetch(memc
, y
);
726 if (instance
->fd
== fds
[x
].fd
)
739 Eventually we will just kill off the server with the problem.
741 void memcached_io_reset(memcached_server_write_instance_st ptr
)
743 memcached_quit_server(ptr
, true);
747 * Read a given number of bytes from the server and place it into a specific
748 * buffer. Reset the IO channel on this server if an error occurs.
750 memcached_return_t
memcached_safe_read(memcached_server_write_instance_st ptr
,
755 char *data
= static_cast<char *>(dta
);
757 while (offset
< size
)
760 memcached_return_t rc
;
762 while (memcached_continue(rc
= memcached_io_read(ptr
, data
+ offset
, size
- offset
, nread
))) { };
764 if (memcached_failed(rc
))
769 offset
+= size_t(nread
);
772 return MEMCACHED_SUCCESS
;
775 memcached_return_t
memcached_io_readline(memcached_server_write_instance_st ptr
,
781 bool line_complete
= false;
783 while (line_complete
== false)
785 if (ptr
->read_buffer_length
== 0)
788 * We don't have any data in the buffer, so let's fill the read
789 * buffer. Call the standard read function to avoid duplicating
793 memcached_return_t rc
= memcached_io_read(ptr
, buffer_ptr
, 1, nread
);
794 if (memcached_failed(rc
) and rc
== MEMCACHED_IN_PROGRESS
)
796 memcached_quit_server(ptr
, true);
797 return memcached_set_error(*ptr
, rc
, MEMCACHED_AT
);
799 else if (memcached_failed(rc
))
804 if (*buffer_ptr
== '\n')
813 /* Now let's look in the buffer and copy as we go! */
814 while (ptr
->read_buffer_length
&& total_nr
< size
&& !line_complete
)
816 *buffer_ptr
= *ptr
->read_ptr
;
817 if (*buffer_ptr
== '\n')
819 line_complete
= true;
821 --ptr
->read_buffer_length
;
827 if (total_nr
== size
)
829 return MEMCACHED_PROTOCOL_ERROR
;
833 return MEMCACHED_SUCCESS
;