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 */
71 if ((nr
= recv(ptr
->fd
,
72 ptr
->read_ptr
+ ptr
->read_data_length
,
73 MEMCACHED_MAX_BUFFER
- ptr
->read_data_length
,
78 memcached_set_error(*ptr
, MEMCACHED_CONNECTION_FAILURE
, MEMCACHED_AT
);
82 switch (get_socket_errno())
87 #if EWOULDBLOCK != EAGAIN
91 #ifdef TARGET_OS_LINUX
94 break; // No IO is fine, we can just move on
97 memcached_set_errno(*ptr
, get_socket_errno(), MEMCACHED_AT
);
103 else // We read data, append to our read buffer
105 ptr
->read_data_length
+= size_t(nr
);
106 ptr
->read_buffer_length
+= size_t(nr
);
117 * If the we have callbacks connected to this server structure
118 * we may start process the input queue and fire the callbacks
119 * for the incomming messages. This function is _only_ called
120 * when the input buffer is full, so that we _know_ that we have
121 * at least _one_ message to process.
123 * @param ptr the server to star processing iput messages for
124 * @return true if we processed anything, false otherwise
126 static bool process_input_buffer(memcached_server_write_instance_st ptr
)
129 ** We might be able to process some of the response messages if we
130 ** have a callback set up
132 if (ptr
->root
->callbacks
!= NULL
)
135 * We might have responses... try to read them out and fire
138 memcached_callback_st cb
= *ptr
->root
->callbacks
;
140 memcached_set_processing_input((memcached_st
*)ptr
->root
, true);
142 char buffer
[MEMCACHED_DEFAULT_COMMAND_SIZE
];
143 memcached_st
*root
= (memcached_st
*)ptr
->root
;
144 memcached_return_t error
= memcached_response(ptr
, buffer
, sizeof(buffer
), &root
->result
);
146 memcached_set_processing_input(root
, false);
148 if (error
== MEMCACHED_SUCCESS
)
150 for (unsigned int x
= 0; x
< cb
.number_of_callback
; x
++)
152 error
= (*cb
.callback
[x
])(ptr
->root
, &root
->result
, cb
.context
);
153 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
)
172 ** We are going to block on write, but at least on Solaris we might block
173 ** on write if we haven't read anything from our input buffer..
174 ** Try to purge the input buffer if we don't do any flow control in the
175 ** application layer (just sending a lot of data etc)
176 ** The test is moved down in the purge function to avoid duplication of
179 if (read_or_write
== MEM_WRITE
)
181 if (memcached_purge(ptr
) == false)
183 return MEMCACHED_FAILURE
;
192 if (read_or_write
== MEM_WRITE
) /* write */
195 ptr
->io_wait_count
.write
++;
199 ptr
->io_wait_count
.read
++;
202 if (ptr
->root
->poll_timeout
== 0) // Mimic 0 causes timeout behavior (not all platforms do this)
204 ptr
->io_wait_count
.timeouts
++;
205 return memcached_set_error(*ptr
, MEMCACHED_TIMEOUT
, MEMCACHED_AT
);
210 while (--loop_max
) // While loop is for ERESTART or EINTR
212 int active_fd
= poll(&fds
, 1, ptr
->root
->poll_timeout
);
216 assert_msg(active_fd
== 1 , "poll() returned an unexpected value");
217 return MEMCACHED_SUCCESS
;
219 else if (active_fd
== 0)
221 ptr
->io_wait_count
.timeouts
++;
222 return memcached_set_error(*ptr
, MEMCACHED_TIMEOUT
, MEMCACHED_AT
);
225 // Only an error should result in this code being called.
226 local_errno
= get_socket_errno(); // We cache in case memcached_quit_server() modifies errno
227 assert_msg(active_fd
== -1 , "poll() returned an unexpected value");
230 #ifdef TARGET_OS_LINUX
238 return memcached_set_error(*ptr
, MEMCACHED_MEMORY_ALLOCATION_FAILURE
, MEMCACHED_AT
);
241 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"));
244 if (fds
.revents
& POLLERR
)
247 socklen_t len
= sizeof (err
);
248 if (getsockopt(ptr
->fd
, SOL_SOCKET
, SO_ERROR
, &err
, &len
) == 0)
250 if (err
== 0) // treat this as EINTR
260 break; // should only occur from poll error
263 memcached_quit_server(ptr
, true);
265 return memcached_set_errno(*ptr
, local_errno
, MEMCACHED_AT
);
268 static bool io_flush(memcached_server_write_instance_st ptr
,
269 const bool with_flush
,
270 memcached_return_t
& error
)
273 ** We might want to purge the input buffer if we haven't consumed
274 ** any output yet... The test for the limits is the purge is inline
275 ** in the purge function to avoid duplicating the logic..
278 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
280 if (memcached_purge(ptr
) == false)
285 char *local_write_ptr
= ptr
->write_buffer
;
286 size_t write_length
= ptr
->write_buffer_offset
;
288 error
= MEMCACHED_SUCCESS
;
290 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
292 /* Looking for memory overflows */
294 if (write_length
== MEMCACHED_MAX_BUFFER
)
295 WATCHPOINT_ASSERT(ptr
->write_buffer
== local_write_ptr
);
296 WATCHPOINT_ASSERT((ptr
->write_buffer
+ MEMCACHED_MAX_BUFFER
) >= (local_write_ptr
+ write_length
));
301 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
302 WATCHPOINT_ASSERT(write_length
> 0);
304 int flags
= with_flush
? MSG_NOSIGNAL
|MSG_DONTWAIT
: MSG_NOSIGNAL
|MSG_DONTWAIT
|MSG_MORE
;
305 ssize_t sent_length
= ::send(ptr
->fd
, local_write_ptr
, write_length
, flags
);
307 if (sent_length
== SOCKET_ERROR
)
309 #if 0 // @todo I should look at why we hit this bit of code hard frequently
310 WATCHPOINT_ERRNO(get_socket_errno());
311 WATCHPOINT_NUMBER(get_socket_errno());
313 switch (get_socket_errno())
318 #if EWOULDBLOCK != EAGAIN
324 * We may be blocked on write because the input buffer
325 * is full. Let's check if we have room in our input
326 * buffer for more data and retry the write before
329 if (repack_input_buffer(ptr
) or process_input_buffer(ptr
))
334 memcached_return_t rc
= io_wait(ptr
, MEM_WRITE
);
335 if (memcached_success(rc
))
339 else if (rc
== MEMCACHED_TIMEOUT
)
344 memcached_quit_server(ptr
, true);
345 error
= memcached_set_errno(*ptr
, get_socket_errno(), MEMCACHED_AT
);
351 memcached_quit_server(ptr
, true);
352 error
= memcached_set_errno(*ptr
, get_socket_errno(), MEMCACHED_AT
);
353 WATCHPOINT_ASSERT(ptr
->fd
== INVALID_SOCKET
);
358 ptr
->io_bytes_sent
+= uint32_t(sent_length
);
360 local_write_ptr
+= sent_length
;
361 write_length
-= uint32_t(sent_length
);
364 WATCHPOINT_ASSERT(write_length
== 0);
365 ptr
->write_buffer_offset
= 0;
370 memcached_return_t
memcached_io_wait_for_write(memcached_server_write_instance_st ptr
)
372 return io_wait(ptr
, MEM_WRITE
);
375 memcached_return_t
memcached_io_read(memcached_server_write_instance_st ptr
,
376 void *buffer
, size_t length
, ssize_t
& nread
)
378 assert(memcached_is_udp(ptr
->root
) == false);
379 assert_msg(ptr
, "Programmer error, memcached_io_read() recieved an invalid memcached_server_write_instance_st"); // Programmer error
380 char *buffer_ptr
= static_cast<char *>(buffer
);
382 if (ptr
->fd
== INVALID_SOCKET
)
385 assert_msg(int(ptr
->state
) <= int(MEMCACHED_SERVER_STATE_ADDRINFO
), "Programmer error, invalid socket state");
387 return MEMCACHED_CONNECTION_FAILURE
;
392 if (ptr
->read_buffer_length
== 0)
397 data_read
= ::recv(ptr
->fd
, ptr
->read_buffer
, MEMCACHED_MAX_BUFFER
, MSG_DONTWAIT
);
398 if (data_read
== SOCKET_ERROR
)
400 switch (get_socket_errno())
402 case EINTR
: // We just retry
405 case ETIMEDOUT
: // OSX
406 #if EWOULDBLOCK != EAGAIN
410 #ifdef TARGET_OS_LINUX
414 memcached_return_t io_wait_ret
;
415 if (memcached_success(io_wait_ret
= io_wait(ptr
, MEM_READ
)))
425 case ENOTCONN
: // Programmer Error
426 WATCHPOINT_ASSERT(0);
428 WATCHPOINT_ASSERT(0);
430 assert_msg(ptr
->fd
!= INVALID_SOCKET
, "Programmer error, invalid socket");
436 memcached_quit_server(ptr
, true);
438 return memcached_set_errno(*ptr
, get_socket_errno(), MEMCACHED_AT
);
442 else if (data_read
== 0)
445 EOF. Any data received so far is incomplete
446 so discard it. This always reads by byte in case of TCP
447 and protocol enforcement happens at memcached_response()
448 looking for '\n'. We do not care for UDB which requests 8 bytes
449 at once. Generally, this means that connection went away. Since
450 for blocking I/O we do not return 0 and for non-blocking case
451 it will return EGAIN if data is not immediatly available.
453 WATCHPOINT_STRING("We had a zero length recv()");
454 memcached_quit_server(ptr
, true);
456 return memcached_set_error(*ptr
, MEMCACHED_CONNECTION_FAILURE
, MEMCACHED_AT
,
457 memcached_literal_param("::rec() returned zero, server has disconnected"));
459 } while (data_read
<= 0);
461 ptr
->io_bytes_sent
= 0;
462 ptr
->read_data_length
= (size_t) data_read
;
463 ptr
->read_buffer_length
= (size_t) data_read
;
464 ptr
->read_ptr
= ptr
->read_buffer
;
471 difference
= (length
> ptr
->read_buffer_length
) ? ptr
->read_buffer_length
: length
;
473 memcpy(buffer_ptr
, ptr
->read_ptr
, difference
);
474 length
-= difference
;
475 ptr
->read_ptr
+= difference
;
476 ptr
->read_buffer_length
-= difference
;
477 buffer_ptr
+= difference
;
481 *buffer_ptr
= *ptr
->read_ptr
;
483 ptr
->read_buffer_length
--;
489 nread
= ssize_t(buffer_ptr
- (char*)buffer
);
491 return MEMCACHED_SUCCESS
;
494 memcached_return_t
memcached_io_slurp(memcached_server_write_instance_st ptr
)
496 assert_msg(ptr
, "Programmer error, invalid memcached_server_write_instance_st");
497 assert(memcached_is_udp(ptr
->root
) == false);
499 if (ptr
->fd
== INVALID_SOCKET
)
501 assert_msg(int(ptr
->state
) <= int(MEMCACHED_SERVER_STATE_ADDRINFO
), "Invalid socket state");
502 return MEMCACHED_CONNECTION_FAILURE
;
506 char buffer
[MEMCACHED_MAX_BUFFER
];
509 data_read
= recv(ptr
->fd
, ptr
->read_buffer
, sizeof(buffer
), MSG_DONTWAIT
);
510 if (data_read
== SOCKET_ERROR
)
512 switch (get_socket_errno())
514 case EINTR
: // We just retry
517 case ETIMEDOUT
: // OSX
518 #if EWOULDBLOCK != EAGAIN
522 #ifdef TARGET_OS_LINUX
525 if (memcached_success(io_wait(ptr
, MEM_READ
)))
529 return MEMCACHED_IN_PROGRESS
;
533 case ENOTCONN
: // Programmer Error
538 assert_msg(ptr
->fd
!= INVALID_SOCKET
, "Invalid socket state");
543 return MEMCACHED_CONNECTION_FAILURE
; // We want this!
546 } while (data_read
> 0);
548 return MEMCACHED_CONNECTION_FAILURE
;
551 static bool _io_write(memcached_server_write_instance_st ptr
,
552 const void *buffer
, size_t length
, bool with_flush
,
555 assert(ptr
->fd
!= INVALID_SOCKET
);
556 assert(memcached_is_udp(ptr
->root
) == false);
558 const char *buffer_ptr
= static_cast<const char *>(buffer
);
560 const size_t original_length
= length
;
565 size_t buffer_end
= MEMCACHED_MAX_BUFFER
;
566 size_t should_write
= buffer_end
-ptr
->write_buffer_offset
;
567 should_write
= (should_write
< length
) ? should_write
: length
;
569 write_ptr
= ptr
->write_buffer
+ ptr
->write_buffer_offset
;
570 memcpy(write_ptr
, buffer_ptr
, should_write
);
571 ptr
->write_buffer_offset
+= should_write
;
572 buffer_ptr
+= should_write
;
573 length
-= should_write
;
575 if (ptr
->write_buffer_offset
== buffer_end
)
577 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
579 memcached_return_t rc
;
580 if (io_flush(ptr
, with_flush
, rc
) == false)
582 written
= original_length
-length
;
590 memcached_return_t rc
;
591 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
592 if (io_flush(ptr
, with_flush
, rc
) == false)
594 written
= original_length
-length
;
599 written
= original_length
-length
;
604 bool memcached_io_write(memcached_server_write_instance_st ptr
)
607 return _io_write(ptr
, NULL
, 0, true, written
);
610 ssize_t
memcached_io_write(memcached_server_write_instance_st ptr
,
611 const void *buffer
, const size_t length
, const bool with_flush
)
615 if (_io_write(ptr
, buffer
, length
, with_flush
, written
) == false)
620 return ssize_t(written
);
623 bool memcached_io_writev(memcached_server_write_instance_st ptr
,
624 libmemcached_io_vector_st vector
[],
625 const size_t number_of
, const bool with_flush
)
627 ssize_t complete_total
= 0;
630 for (size_t x
= 0; x
< number_of
; x
++, vector
++)
632 complete_total
+= vector
->length
;
636 if ((_io_write(ptr
, vector
->buffer
, vector
->length
, false, written
)) == false)
646 if (memcached_io_write(ptr
) == false)
652 return (complete_total
== total
);
656 void memcached_io_close(memcached_server_write_instance_st ptr
)
658 if (ptr
->fd
== INVALID_SOCKET
)
663 /* in case of death shutdown to avoid blocking at close() */
664 if (shutdown(ptr
->fd
, SHUT_RDWR
) == SOCKET_ERROR
&& get_socket_errno() != ENOTCONN
)
666 WATCHPOINT_NUMBER(ptr
->fd
);
667 WATCHPOINT_ERRNO(get_socket_errno());
668 WATCHPOINT_ASSERT(get_socket_errno());
671 if (closesocket(ptr
->fd
) == SOCKET_ERROR
)
673 WATCHPOINT_ERRNO(get_socket_errno());
675 ptr
->state
= MEMCACHED_SERVER_STATE_NEW
;
676 ptr
->fd
= INVALID_SOCKET
;
679 memcached_server_write_instance_st
memcached_io_get_readable_server(memcached_st
*memc
)
681 #define MAX_SERVERS_TO_POLL 100
682 struct pollfd fds
[MAX_SERVERS_TO_POLL
];
683 nfds_t host_index
= 0;
685 for (uint32_t x
= 0; x
< memcached_server_count(memc
) and host_index
< MAX_SERVERS_TO_POLL
; ++x
)
687 memcached_server_write_instance_st instance
= memcached_server_instance_fetch(memc
, x
);
689 if (instance
->read_buffer_length
> 0) /* I have data in the buffer */
694 if (memcached_server_response_count(instance
) > 0)
696 fds
[host_index
].events
= POLLIN
;
697 fds
[host_index
].revents
= 0;
698 fds
[host_index
].fd
= instance
->fd
;
705 /* We have 0 or 1 server with pending events.. */
706 for (uint32_t x
= 0; x
< memcached_server_count(memc
); ++x
)
708 memcached_server_write_instance_st instance
=
709 memcached_server_instance_fetch(memc
, x
);
711 if (memcached_server_response_count(instance
) > 0)
720 int error
= poll(fds
, host_index
, memc
->poll_timeout
);
724 memcached_set_errno(*memc
, get_socket_errno(), MEMCACHED_AT
);
730 for (nfds_t x
= 0; x
< host_index
; ++x
)
732 if (fds
[x
].revents
& POLLIN
)
734 for (uint32_t y
= 0; y
< memcached_server_count(memc
); ++y
)
736 memcached_server_write_instance_st instance
= memcached_server_instance_fetch(memc
, y
);
738 if (instance
->fd
== fds
[x
].fd
)
751 Eventually we will just kill off the server with the problem.
753 void memcached_io_reset(memcached_server_write_instance_st ptr
)
755 memcached_quit_server(ptr
, true);
759 * Read a given number of bytes from the server and place it into a specific
760 * buffer. Reset the IO channel on this server if an error occurs.
762 memcached_return_t
memcached_safe_read(memcached_server_write_instance_st ptr
,
767 char *data
= static_cast<char *>(dta
);
769 while (offset
< size
)
772 memcached_return_t rc
;
774 while (memcached_continue(rc
= memcached_io_read(ptr
, data
+ offset
, size
- offset
, nread
))) { };
776 if (memcached_failed(rc
))
781 offset
+= size_t(nread
);
784 return MEMCACHED_SUCCESS
;
787 memcached_return_t
memcached_io_readline(memcached_server_write_instance_st ptr
,
793 bool line_complete
= false;
795 while (line_complete
== false)
797 if (ptr
->read_buffer_length
== 0)
800 * We don't have any data in the buffer, so let's fill the read
801 * buffer. Call the standard read function to avoid duplicating
805 memcached_return_t rc
= memcached_io_read(ptr
, buffer_ptr
, 1, nread
);
806 if (memcached_failed(rc
) and rc
== MEMCACHED_IN_PROGRESS
)
808 memcached_quit_server(ptr
, true);
809 return memcached_set_error(*ptr
, rc
, MEMCACHED_AT
);
811 else if (memcached_failed(rc
))
816 if (*buffer_ptr
== '\n')
825 /* Now let's look in the buffer and copy as we go! */
826 while (ptr
->read_buffer_length
and total_nr
< size
and line_complete
== false)
828 *buffer_ptr
= *ptr
->read_ptr
;
829 if (*buffer_ptr
== '\n')
831 line_complete
= true;
833 --ptr
->read_buffer_length
;
839 if (total_nr
== size
)
841 return MEMCACHED_PROTOCOL_ERROR
;
845 return MEMCACHED_SUCCESS
;