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
)
159 /* @todo what should I do with the error message??? */
161 /* @todo what should I do with other error messages?? */
168 static memcached_return_t
io_wait(memcached_server_write_instance_st ptr
,
169 const memc_read_or_write read_or_write
)
175 if (read_or_write
== MEM_WRITE
) /* write */
178 WATCHPOINT_SET(ptr
->io_wait_count
.write
++);
182 WATCHPOINT_SET(ptr
->io_wait_count
.read
++);
186 ** We are going to block on write, but at least on Solaris we might block
187 ** on write if we haven't read anything from our input buffer..
188 ** Try to purge the input buffer if we don't do any flow control in the
189 ** application layer (just sending a lot of data etc)
190 ** The test is moved down in the purge function to avoid duplication of
193 if (read_or_write
== MEM_WRITE
)
195 memcached_return_t rc
= memcached_purge(ptr
);
196 if (memcached_fatal(rc
))
198 return MEMCACHED_FAILURE
;
202 if (ptr
->root
->poll_timeout
== 0) // Mimic 0 causes timeout behavior (not all platforms do this)
204 return memcached_set_error(*ptr
, MEMCACHED_TIMEOUT
, MEMCACHED_AT
);
208 while (--loop_max
) // While loop is for ERESTART or EINTR
211 int error
= poll(&fds
, 1, ptr
->root
->poll_timeout
);
215 WATCHPOINT_IF_LABELED_NUMBER(read_or_write
&& loop_max
< 4, "read() times we had to loop, decremented down from 5", loop_max
);
216 WATCHPOINT_IF_LABELED_NUMBER(!read_or_write
&& loop_max
< 4, "write() times we had to loop, decremented down from 5", loop_max
);
218 return MEMCACHED_SUCCESS
;
220 case 0: // Timeout occured, we let the while() loop do its thing.
221 return memcached_set_error(*ptr
, MEMCACHED_TIMEOUT
, MEMCACHED_AT
);
224 WATCHPOINT_ERRNO(get_socket_errno());
225 switch (get_socket_errno())
227 #ifdef TARGET_OS_LINUX
235 return memcached_set_error(*ptr
, MEMCACHED_MEMORY_ALLOCATION_FAILURE
, MEMCACHED_AT
);
238 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"));
241 if (fds
.revents
& POLLERR
)
244 socklen_t len
= sizeof (err
);
245 if (getsockopt(ptr
->fd
, SOL_SOCKET
, SO_ERROR
, &err
, &len
) == 0)
256 memcached_set_errno(*ptr
, get_socket_errno(), MEMCACHED_AT
);
258 int local_errno
= get_socket_errno(); // We cache in case memcached_quit_server() modifies errno
259 memcached_quit_server(ptr
, true);
261 return memcached_set_errno(*ptr
, local_errno
, MEMCACHED_AT
);
266 memcached_quit_server(ptr
, true);
268 return memcached_set_errno(*ptr
, get_socket_errno(), MEMCACHED_AT
);
271 static bool io_flush(memcached_server_write_instance_st ptr
,
272 const bool with_flush
,
273 memcached_return_t
& error
)
276 ** We might want to purge the input buffer if we haven't consumed
277 ** any output yet... The test for the limits is the purge is inline
278 ** in the purge function to avoid duplicating the logic..
281 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
282 memcached_return_t rc
= memcached_purge(ptr
);
284 if (rc
!= MEMCACHED_SUCCESS
and rc
!= MEMCACHED_STORED
)
289 char *local_write_ptr
= ptr
->write_buffer
;
290 size_t write_length
= ptr
->write_buffer_offset
;
292 error
= MEMCACHED_SUCCESS
;
294 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
296 /* Looking for memory overflows */
298 if (write_length
== MEMCACHED_MAX_BUFFER
)
299 WATCHPOINT_ASSERT(ptr
->write_buffer
== local_write_ptr
);
300 WATCHPOINT_ASSERT((ptr
->write_buffer
+ MEMCACHED_MAX_BUFFER
) >= (local_write_ptr
+ write_length
));
305 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
306 WATCHPOINT_ASSERT(write_length
> 0);
308 ssize_t sent_length
= 0;
309 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
312 sent_length
= ::send(ptr
->fd
, local_write_ptr
, write_length
, MSG_NOSIGNAL
|MSG_DONTWAIT
);
316 sent_length
= ::send(ptr
->fd
, local_write_ptr
, write_length
, MSG_NOSIGNAL
|MSG_DONTWAIT
|MSG_MORE
);
319 if (sent_length
== SOCKET_ERROR
)
321 #if 0 // @todo I should look at why we hit this bit of code hard frequently
322 WATCHPOINT_ERRNO(get_socket_errno());
323 WATCHPOINT_NUMBER(get_socket_errno());
325 switch (get_socket_errno())
330 #if EWOULDBLOCK != EAGAIN
336 * We may be blocked on write because the input buffer
337 * is full. Let's check if we have room in our input
338 * buffer for more data and retry the write before
341 if (repack_input_buffer(ptr
) or process_input_buffer(ptr
))
346 memcached_return_t rc
= io_wait(ptr
, MEM_WRITE
);
347 if (memcached_success(rc
))
351 else if (rc
== MEMCACHED_TIMEOUT
)
353 error
= memcached_set_error(*ptr
, MEMCACHED_TIMEOUT
, MEMCACHED_AT
);
357 memcached_quit_server(ptr
, true);
358 error
= memcached_set_errno(*ptr
, get_socket_errno(), MEMCACHED_AT
);
364 memcached_quit_server(ptr
, true);
365 error
= memcached_set_errno(*ptr
, get_socket_errno(), MEMCACHED_AT
);
366 WATCHPOINT_ASSERT(ptr
->fd
== INVALID_SOCKET
);
371 ptr
->io_bytes_sent
+= uint32_t(sent_length
);
373 local_write_ptr
+= sent_length
;
374 write_length
-= uint32_t(sent_length
);
377 WATCHPOINT_ASSERT(write_length
== 0);
378 ptr
->write_buffer_offset
= 0;
383 memcached_return_t
memcached_io_wait_for_write(memcached_server_write_instance_st ptr
)
385 return io_wait(ptr
, MEM_WRITE
);
388 memcached_return_t
memcached_io_read(memcached_server_write_instance_st ptr
,
389 void *buffer
, size_t length
, ssize_t
& nread
)
391 assert(memcached_is_udp(ptr
->root
) == false);
392 assert_msg(ptr
, "Programmer error, memcached_io_read() recieved an invalid memcached_server_write_instance_st"); // Programmer error
393 char *buffer_ptr
= static_cast<char *>(buffer
);
395 if (ptr
->fd
== INVALID_SOCKET
)
398 assert_msg(int(ptr
->state
) <= int(MEMCACHED_SERVER_STATE_ADDRINFO
), "Programmer error, invalid socket state");
400 return MEMCACHED_CONNECTION_FAILURE
;
405 if (not ptr
->read_buffer_length
)
410 data_read
= ::recv(ptr
->fd
, ptr
->read_buffer
, MEMCACHED_MAX_BUFFER
, MSG_DONTWAIT
);
411 if (data_read
== SOCKET_ERROR
)
413 switch (get_socket_errno())
415 case EINTR
: // We just retry
418 case ETIMEDOUT
: // OSX
419 #if EWOULDBLOCK != EAGAIN
423 #ifdef TARGET_OS_LINUX
426 if (memcached_success(io_wait(ptr
, MEM_READ
)))
430 return MEMCACHED_IN_PROGRESS
;
434 case ENOTCONN
: // Programmer Error
435 WATCHPOINT_ASSERT(0);
437 WATCHPOINT_ASSERT(0);
439 assert_msg(ptr
->fd
!= INVALID_SOCKET
, "Programmer error, invalid socket");
445 memcached_quit_server(ptr
, true);
447 return memcached_set_errno(*ptr
, get_socket_errno(), MEMCACHED_AT
);
451 else if (data_read
== 0)
454 EOF. Any data received so far is incomplete
455 so discard it. This always reads by byte in case of TCP
456 and protocol enforcement happens at memcached_response()
457 looking for '\n'. We do not care for UDB which requests 8 bytes
458 at once. Generally, this means that connection went away. Since
459 for blocking I/O we do not return 0 and for non-blocking case
460 it will return EGAIN if data is not immediatly available.
462 WATCHPOINT_STRING("We had a zero length recv()");
463 memcached_quit_server(ptr
, true);
465 return memcached_set_error(*ptr
, MEMCACHED_CONNECTION_FAILURE
, MEMCACHED_AT
,
466 memcached_literal_param("::rec() returned zero, server has disconnected"));
468 } while (data_read
<= 0);
470 ptr
->io_bytes_sent
= 0;
471 ptr
->read_data_length
= (size_t) data_read
;
472 ptr
->read_buffer_length
= (size_t) data_read
;
473 ptr
->read_ptr
= ptr
->read_buffer
;
480 difference
= (length
> ptr
->read_buffer_length
) ? ptr
->read_buffer_length
: length
;
482 memcpy(buffer_ptr
, ptr
->read_ptr
, difference
);
483 length
-= difference
;
484 ptr
->read_ptr
+= difference
;
485 ptr
->read_buffer_length
-= difference
;
486 buffer_ptr
+= difference
;
490 *buffer_ptr
= *ptr
->read_ptr
;
492 ptr
->read_buffer_length
--;
498 nread
= ssize_t(buffer_ptr
- (char*)buffer
);
500 return MEMCACHED_SUCCESS
;
503 memcached_return_t
memcached_io_slurp(memcached_server_write_instance_st ptr
)
505 assert_msg(ptr
, "Programmer error, invalid memcached_server_write_instance_st");
506 assert(memcached_is_udp(ptr
->root
) == false);
508 if (ptr
->fd
== INVALID_SOCKET
)
510 assert_msg(int(ptr
->state
) <= int(MEMCACHED_SERVER_STATE_ADDRINFO
), "Invalid socket state");
511 return MEMCACHED_CONNECTION_FAILURE
;
515 char buffer
[MEMCACHED_MAX_BUFFER
];
518 data_read
= recv(ptr
->fd
, ptr
->read_buffer
, sizeof(buffer
), MSG_DONTWAIT
);
519 if (data_read
== SOCKET_ERROR
)
521 switch (get_socket_errno())
523 case EINTR
: // We just retry
526 case ETIMEDOUT
: // OSX
527 #if EWOULDBLOCK != EAGAIN
531 #ifdef TARGET_OS_LINUX
534 if (memcached_success(io_wait(ptr
, MEM_READ
)))
538 return MEMCACHED_IN_PROGRESS
;
542 case ENOTCONN
: // Programmer Error
543 WATCHPOINT_ASSERT(0);
545 WATCHPOINT_ASSERT(0);
547 assert_msg(ptr
->fd
!= INVALID_SOCKET
, "Invalid socket state");
552 return MEMCACHED_CONNECTION_FAILURE
; // We want this!
555 } while (data_read
> 0);
557 return MEMCACHED_CONNECTION_FAILURE
;
560 static ssize_t
_io_write(memcached_server_write_instance_st ptr
,
561 const void *buffer
, size_t length
, bool with_flush
)
563 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
564 assert(memcached_is_udp(ptr
->root
) == false);
566 size_t original_length
= length
;
567 const char *buffer_ptr
= static_cast<const char *>(buffer
);
572 size_t buffer_end
= MEMCACHED_MAX_BUFFER
;
573 size_t should_write
= buffer_end
-ptr
->write_buffer_offset
;
574 should_write
= (should_write
< length
) ? should_write
: length
;
576 write_ptr
= ptr
->write_buffer
+ ptr
->write_buffer_offset
;
577 memcpy(write_ptr
, buffer_ptr
, should_write
);
578 ptr
->write_buffer_offset
+= should_write
;
579 buffer_ptr
+= should_write
;
580 length
-= should_write
;
582 if (ptr
->write_buffer_offset
== buffer_end
)
584 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
586 memcached_return_t rc
;
587 if (io_flush(ptr
, with_flush
, rc
) == false)
596 memcached_return_t rc
;
597 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
598 if (io_flush(ptr
, with_flush
, rc
) == false)
604 return (ssize_t
) original_length
;
607 bool memcached_io_write(memcached_server_write_instance_st ptr
)
609 return (_io_write(ptr
, NULL
, 0, true) >= 0);
612 ssize_t
memcached_io_write(memcached_server_write_instance_st ptr
,
613 const void *buffer
, const size_t length
, const bool with_flush
)
615 return _io_write(ptr
, buffer
, length
, with_flush
);
618 ssize_t
memcached_io_writev(memcached_server_write_instance_st ptr
,
619 libmemcached_io_vector_st vector
[],
620 const size_t number_of
, const bool with_flush
)
624 for (size_t x
= 0; x
< number_of
; x
++, vector
++)
630 if ((returnable
= _io_write(ptr
, vector
->buffer
, vector
->length
, false)) == -1)
640 if (memcached_io_write(ptr
) == false)
650 void memcached_io_close(memcached_server_write_instance_st ptr
)
652 if (ptr
->fd
== INVALID_SOCKET
)
657 /* in case of death shutdown to avoid blocking at close() */
658 if (shutdown(ptr
->fd
, SHUT_RDWR
) == SOCKET_ERROR
&& get_socket_errno() != ENOTCONN
)
660 WATCHPOINT_NUMBER(ptr
->fd
);
661 WATCHPOINT_ERRNO(get_socket_errno());
662 WATCHPOINT_ASSERT(get_socket_errno());
665 if (closesocket(ptr
->fd
) == SOCKET_ERROR
)
667 WATCHPOINT_ERRNO(get_socket_errno());
669 ptr
->state
= MEMCACHED_SERVER_STATE_NEW
;
670 ptr
->fd
= INVALID_SOCKET
;
673 memcached_server_write_instance_st
memcached_io_get_readable_server(memcached_st
*memc
)
675 #define MAX_SERVERS_TO_POLL 100
676 struct pollfd fds
[MAX_SERVERS_TO_POLL
];
677 nfds_t host_index
= 0;
679 for (uint32_t x
= 0; x
< memcached_server_count(memc
) and host_index
< MAX_SERVERS_TO_POLL
; ++x
)
681 memcached_server_write_instance_st instance
= memcached_server_instance_fetch(memc
, x
);
683 if (instance
->read_buffer_length
> 0) /* I have data in the buffer */
688 if (memcached_server_response_count(instance
) > 0)
690 fds
[host_index
].events
= POLLIN
;
691 fds
[host_index
].revents
= 0;
692 fds
[host_index
].fd
= instance
->fd
;
699 /* We have 0 or 1 server with pending events.. */
700 for (uint32_t x
= 0; x
< memcached_server_count(memc
); ++x
)
702 memcached_server_write_instance_st instance
=
703 memcached_server_instance_fetch(memc
, x
);
705 if (memcached_server_response_count(instance
) > 0)
714 int error
= poll(fds
, host_index
, memc
->poll_timeout
);
718 memcached_set_errno(*memc
, get_socket_errno(), MEMCACHED_AT
);
724 for (nfds_t x
= 0; x
< host_index
; ++x
)
726 if (fds
[x
].revents
& POLLIN
)
728 for (uint32_t y
= 0; y
< memcached_server_count(memc
); ++y
)
730 memcached_server_write_instance_st instance
= memcached_server_instance_fetch(memc
, y
);
732 if (instance
->fd
== fds
[x
].fd
)
745 Eventually we will just kill off the server with the problem.
747 void memcached_io_reset(memcached_server_write_instance_st ptr
)
749 memcached_quit_server(ptr
, true);
753 * Read a given number of bytes from the server and place it into a specific
754 * buffer. Reset the IO channel on this server if an error occurs.
756 memcached_return_t
memcached_safe_read(memcached_server_write_instance_st ptr
,
761 char *data
= static_cast<char *>(dta
);
763 while (offset
< size
)
766 memcached_return_t rc
;
768 while (memcached_continue(rc
= memcached_io_read(ptr
, data
+ offset
, size
- offset
, nread
))) { };
770 if (memcached_failed(rc
))
775 offset
+= size_t(nread
);
778 return MEMCACHED_SUCCESS
;
781 memcached_return_t
memcached_io_readline(memcached_server_write_instance_st ptr
,
787 bool line_complete
= false;
789 while (line_complete
== false)
791 if (ptr
->read_buffer_length
== 0)
794 * We don't have any data in the buffer, so let's fill the read
795 * buffer. Call the standard read function to avoid duplicating
799 memcached_return_t rc
= memcached_io_read(ptr
, buffer_ptr
, 1, nread
);
800 if (memcached_failed(rc
) and rc
== MEMCACHED_IN_PROGRESS
)
802 memcached_quit_server(ptr
, true);
803 return memcached_set_error(*ptr
, rc
, MEMCACHED_AT
);
805 else if (memcached_failed(rc
))
810 if (*buffer_ptr
== '\n')
819 /* Now let's look in the buffer and copy as we go! */
820 while (ptr
->read_buffer_length
&& total_nr
< size
&& !line_complete
)
822 *buffer_ptr
= *ptr
->read_ptr
;
823 if (*buffer_ptr
== '\n')
825 line_complete
= true;
827 --ptr
->read_buffer_length
;
833 if (total_nr
== size
)
835 return MEMCACHED_PROTOCOL_ERROR
;
839 return MEMCACHED_SUCCESS
;