2 +--------------------------------------------------------------------+
3 | libmemcached - C/C++ Client Library for memcached |
4 +--------------------------------------------------------------------+
5 | Redistribution and use in source and binary forms, with or without |
6 | modification, are permitted under the terms of the BSD license. |
7 | You should have received a copy of the license in a bundled file |
8 | named LICENSE; in case you did not receive a copy you can review |
9 | the terms online at: https://opensource.org/licenses/BSD-3-Clause |
10 +--------------------------------------------------------------------+
11 | Copyright (c) 2006-2014 Brian Aker https://datadifferential.com/ |
12 | Copyright (c) 2020 Michael Wallner <mike@php.net> |
13 +--------------------------------------------------------------------+
16 #include "libmemcached/common.h"
18 #include "p9y/socket.hpp"
19 #include "p9y/poll.hpp"
21 void initialize_binary_request(memcached_instance_st
*server
,
22 protocol_binary_request_header
&header
) {
24 header
.request
.magic
= PROTOCOL_BINARY_REQ
;
25 header
.request
.opaque
= htons(server
->request_id
);
28 enum memc_read_or_write
{ MEM_READ
, MEM_WRITE
};
31 * Try to fill the input buffer for a server with as much
34 * @param instance the server to pack
36 static bool repack_input_buffer(memcached_instance_st
*instance
) {
37 if (instance
->read_ptr
!= instance
->read_buffer
) {
38 /* Move all of the data to the beginning of the buffer so
39 ** that we can fit more data into the buffer...
41 memmove(instance
->read_buffer
, instance
->read_ptr
, instance
->read_buffer_length
);
42 instance
->read_ptr
= instance
->read_buffer
;
45 /* There is room in the buffer, try to fill it! */
46 if (instance
->read_buffer_length
!= MEMCACHED_MAX_BUFFER
) {
48 /* Just try a single read to grab what's available */
50 if ((nr
= ::recv(instance
->fd
, instance
->read_ptr
+ instance
->read_buffer_length
,
51 MEMCACHED_MAX_BUFFER
- instance
->read_buffer_length
, MSG_NOSIGNAL
))
55 memcached_set_error(*instance
, MEMCACHED_CONNECTION_FAILURE
, MEMCACHED_AT
);
57 switch (get_socket_errno()) {
61 #if EWOULDBLOCK != EAGAIN
68 break; // No IO is fine, we can just move on
71 memcached_set_errno(*instance
, get_socket_errno(), MEMCACHED_AT
);
76 } else // We read data, append to our read buffer
78 instance
->read_buffer_length
+= size_t(nr
);
89 * If the we have callbacks connected to this server structure
90 * we may start process the input queue and fire the callbacks
91 * for the incomming messages. This function is _only_ called
92 * when the input buffer is full, so that we _know_ that we have
93 * at least _one_ message to process.
95 * @param instance the server to star processing iput messages for
96 * @return true if we processed anything, false otherwise
98 static bool process_input_buffer(memcached_instance_st
*instance
) {
100 ** We might be able to process some of the response messages if we
101 ** have a callback set up
103 if (instance
->root
->callbacks
) {
105 * We might have responses... try to read them out and fire
108 memcached_callback_st cb
= *instance
->root
->callbacks
;
110 memcached_set_processing_input((Memcached
*) instance
->root
, true);
112 char buffer
[MEMCACHED_DEFAULT_COMMAND_SIZE
];
113 Memcached
*root
= (Memcached
*) instance
->root
;
114 memcached_return_t error
= memcached_response(instance
, buffer
, sizeof(buffer
), &root
->result
);
116 memcached_set_processing_input(root
, false);
118 if (error
== MEMCACHED_SUCCESS
) {
119 for (unsigned int x
= 0; x
< cb
.number_of_callback
; x
++) {
120 error
= (*cb
.callback
[x
])(instance
->root
, &root
->result
, cb
.context
);
121 if (error
!= MEMCACHED_SUCCESS
) {
126 /* @todo what should I do with the error message??? */
128 /* @todo what should I do with other error messages?? */
135 static memcached_return_t
io_wait(memcached_instance_st
*instance
, const short events
) {
137 ** We are going to block on write, but at least on Solaris we might block
138 ** on write if we haven't read anything from our input buffer..
139 ** Try to purge the input buffer if we don't do any flow control in the
140 ** application layer (just sending a lot of data etc)
141 ** The test is moved down in the purge function to avoid duplication of
144 if (events
& POLLOUT
) {
145 if (memcached_purge(instance
) == false) {
146 return MEMCACHED_FAILURE
;
151 fds
.fd
= instance
->fd
;
155 if (fds
.events
& POLLOUT
) /* write */ {
156 instance
->io_wait_count
.write
++;
158 instance
->io_wait_count
.read
++;
161 if (instance
->root
->poll_timeout
162 == 0) // Mimic 0 causes timeout behavior (not all platforms do this)
164 return memcached_set_error(*instance
, MEMCACHED_TIMEOUT
, MEMCACHED_AT
,
165 memcached_literal_param("poll_timeout() was set to zero"));
169 while (--loop_max
) // While loop is for ERESTART or EINTR
171 int active_fd
= poll(&fds
, 1, instance
->root
->poll_timeout
);
173 if (active_fd
>= 1) {
174 assert_msg(active_fd
== 1, "poll() returned an unexpected number of active file descriptors");
175 if (fds
.revents
& POLLIN
or fds
.revents
& POLLOUT
) {
176 return MEMCACHED_SUCCESS
;
179 if (fds
.revents
& POLLHUP
) {
180 return memcached_set_error(*instance
, MEMCACHED_CONNECTION_FAILURE
, MEMCACHED_AT
,
181 memcached_literal_param("poll() detected hang up"));
184 if (fds
.revents
& POLLERR
) {
185 int local_errno
= EINVAL
;
187 socklen_t len
= sizeof(err
);
188 if (getsockopt(instance
->fd
, SOL_SOCKET
, SO_ERROR
, (char *) &err
, &len
) == 0) {
189 if (err
== 0) // treat this as EINTR
195 memcached_quit_server(instance
, true);
196 return memcached_set_errno(*instance
, local_errno
, MEMCACHED_AT
,
197 memcached_literal_param("poll() returned POLLHUP"));
200 return memcached_set_error(
201 *instance
, MEMCACHED_FAILURE
, MEMCACHED_AT
,
202 memcached_literal_param("poll() returned a value that was not dealt with"));
205 if (active_fd
== 0) {
206 return memcached_set_error(*instance
, MEMCACHED_TIMEOUT
, MEMCACHED_AT
,
207 memcached_literal_param("No active_fd were found"));
210 // Only an error should result in this code being called.
211 int local_errno
= get_socket_errno(); // We cache in case memcached_quit_server() modifies errno
212 assert_msg(active_fd
== -1, "poll() returned an unexpected value");
213 switch (local_errno
) {
222 memcached_set_error(*instance
, MEMCACHED_MEMORY_ALLOCATION_FAILURE
, MEMCACHED_AT
);
226 memcached_set_error(*instance
, MEMCACHED_MEMORY_ALLOCATION_FAILURE
, MEMCACHED_AT
,
227 memcached_literal_param(
228 "RLIMIT_NOFILE exceeded, or if OSX the timeout value was invalid"));
232 memcached_set_errno(*instance
, local_errno
, MEMCACHED_AT
, memcached_literal_param("poll"));
238 memcached_quit_server(instance
, true);
240 if (memcached_has_error(instance
)) {
241 return memcached_instance_error_return(instance
);
244 return memcached_set_error(
245 *instance
, MEMCACHED_CONNECTION_FAILURE
, MEMCACHED_AT
,
246 memcached_literal_param("number of attempts to call io_wait() failed"));
249 static bool io_flush(memcached_instance_st
*instance
, const bool with_flush
,
250 memcached_return_t
&error
) {
252 ** We might want to purge the input buffer if we haven't consumed
253 ** any output yet... The test for the limits is the purge is inline
254 ** in the purge function to avoid duplicating the logic..
257 WATCHPOINT_ASSERT(instance
->fd
!= INVALID_SOCKET
);
259 if (memcached_purge(instance
) == false) {
263 char *local_write_ptr
= instance
->write_buffer
;
264 size_t write_length
= instance
->write_buffer_offset
;
266 error
= MEMCACHED_SUCCESS
;
268 WATCHPOINT_ASSERT(instance
->fd
!= INVALID_SOCKET
);
270 /* Looking for memory overflows */
272 if (write_length
== MEMCACHED_MAX_BUFFER
)
273 WATCHPOINT_ASSERT(instance
->write_buffer
== local_write_ptr
);
274 WATCHPOINT_ASSERT((instance
->write_buffer
+ MEMCACHED_MAX_BUFFER
)
275 >= (local_write_ptr
+ write_length
));
278 while (write_length
) {
279 WATCHPOINT_ASSERT(instance
->fd
!= INVALID_SOCKET
);
280 WATCHPOINT_ASSERT(write_length
> 0);
284 flags
= MSG_NOSIGNAL
;
286 flags
= MSG_NOSIGNAL
| MSG_MORE
;
289 ssize_t sent_length
= ::send(instance
->fd
, local_write_ptr
, write_length
, flags
);
290 int local_errno
= get_socket_errno(); // We cache in case memcached_quit_server() modifies errno
292 if (sent_length
== SOCKET_ERROR
) {
293 #if 0 // @todo I should look at why we hit this bit of code hard frequently
294 WATCHPOINT_ERRNO(get_socket_errno());
295 WATCHPOINT_NUMBER(get_socket_errno());
297 switch (get_socket_errno()) {
301 #if EWOULDBLOCK != EAGAIN
306 * We may be blocked on write because the input buffer
307 * is full. Let's check if we have room in our input
308 * buffer for more data and retry the write before
311 if (repack_input_buffer(instance
) or process_input_buffer(instance
)) {
315 memcached_return_t rc
= io_wait(instance
, POLLOUT
);
316 if (memcached_success(rc
)) {
318 } else if (rc
== MEMCACHED_TIMEOUT
) {
322 memcached_quit_server(instance
, true);
323 error
= memcached_set_errno(*instance
, local_errno
, MEMCACHED_AT
);
329 memcached_quit_server(instance
, true);
330 error
= memcached_set_errno(*instance
, local_errno
, MEMCACHED_AT
);
331 WATCHPOINT_ASSERT(instance
->fd
== INVALID_SOCKET
);
336 instance
->io_bytes_sent
+= uint32_t(sent_length
);
338 local_write_ptr
+= sent_length
;
339 write_length
-= uint32_t(sent_length
);
342 WATCHPOINT_ASSERT(write_length
== 0);
343 instance
->write_buffer_offset
= 0;
348 memcached_return_t
memcached_io_wait_for_write(memcached_instance_st
*instance
) {
349 return io_wait(instance
, POLLOUT
);
352 memcached_return_t
memcached_io_wait_for_read(memcached_instance_st
*instance
) {
353 return io_wait(instance
, POLLIN
);
356 static memcached_return_t
_io_fill(memcached_instance_st
*instance
) {
359 data_read
= ::recv(instance
->fd
, instance
->read_buffer
, MEMCACHED_MAX_BUFFER
, MSG_NOSIGNAL
);
360 int local_errno
= get_socket_errno(); // We cache in case memcached_quit_server() modifies errno
362 if (data_read
== SOCKET_ERROR
) {
363 switch (get_socket_errno()) {
364 case EINTR
: // We just retry
367 case ETIMEDOUT
: // OSX
368 #if EWOULDBLOCK != EAGAIN
376 memcached_return_t io_wait_ret
;
377 if (memcached_success(io_wait_ret
= io_wait(instance
, POLLIN
))) {
386 case ENOTCONN
: // Programmer Error
387 WATCHPOINT_ASSERT(0);
390 WATCHPOINT_ASSERT(0);
393 assert_msg(instance
->fd
!= INVALID_SOCKET
, "Programmer error, invalid socket");
399 memcached_quit_server(instance
, true);
400 memcached_set_errno(*instance
, local_errno
, MEMCACHED_AT
);
404 return memcached_instance_error_return(instance
);
405 } else if (data_read
== 0) {
407 EOF. Any data received so far is incomplete
408 so discard it. This always reads by byte in case of TCP
409 and protocol enforcement happens at memcached_response()
410 looking for '\n'. We do not care for UDB which requests 8 bytes
411 at once. Generally, this means that connection went away. Since
412 for blocking I/O we do not return 0 and for non-blocking case
413 it will return EGAIN if data is not immediatly available.
415 memcached_quit_server(instance
, true);
416 return memcached_set_error(
417 *instance
, MEMCACHED_CONNECTION_FAILURE
, MEMCACHED_AT
,
418 memcached_literal_param("::rec() returned zero, server has disconnected"));
420 instance
->io_wait_count
._bytes_read
+= data_read
;
421 } while (data_read
<= 0);
423 instance
->io_bytes_sent
= 0;
424 instance
->read_buffer_length
= (size_t) data_read
;
425 instance
->read_ptr
= instance
->read_buffer
;
427 return MEMCACHED_SUCCESS
;
430 memcached_return_t
memcached_io_read(memcached_instance_st
*instance
, void *buffer
, size_t length
,
432 assert(memcached_is_udp(instance
->root
) == false);
435 "Programmer error, memcached_io_read() recieved an invalid Instance"); // Programmer error
436 char *buffer_ptr
= static_cast<char *>(buffer
);
438 if (instance
->fd
== INVALID_SOCKET
) {
440 assert_msg(int(instance
->state
) <= int(MEMCACHED_SERVER_STATE_ADDRINFO
), "Programmer error, invalid socket state");
442 return MEMCACHED_CONNECTION_FAILURE
;
446 if (instance
->read_buffer_length
== 0) {
447 memcached_return_t io_fill_ret
;
448 if (memcached_fatal(io_fill_ret
= _io_fill(instance
))) {
456 (length
> instance
->read_buffer_length
) ? instance
->read_buffer_length
: length
;
458 memcpy(buffer_ptr
, instance
->read_ptr
, difference
);
459 length
-= difference
;
460 instance
->read_ptr
+= difference
;
461 instance
->read_buffer_length
-= difference
;
462 buffer_ptr
+= difference
;
464 *buffer_ptr
= *instance
->read_ptr
;
465 instance
->read_ptr
++;
466 instance
->read_buffer_length
--;
472 nread
= ssize_t(buffer_ptr
- (char *) buffer
);
474 return MEMCACHED_SUCCESS
;
477 memcached_return_t
memcached_io_slurp(memcached_instance_st
*instance
) {
478 assert_msg(instance
, "Programmer error, invalid Instance");
479 assert(memcached_is_udp(instance
->root
) == false);
481 if (instance
->fd
== INVALID_SOCKET
) {
482 assert_msg(int(instance
->state
) <= int(MEMCACHED_SERVER_STATE_ADDRINFO
),
483 "Invalid socket state");
484 return MEMCACHED_CONNECTION_FAILURE
;
488 char buffer
[MEMCACHED_MAX_BUFFER
];
490 data_read
= ::recv(instance
->fd
, instance
->read_buffer
, sizeof(buffer
), MSG_NOSIGNAL
);
491 if (data_read
== SOCKET_ERROR
) {
492 switch (get_socket_errno()) {
493 case EINTR
: // We just retry
496 case ETIMEDOUT
: // OSX
497 #if EWOULDBLOCK != EAGAIN
504 if (memcached_success(io_wait(instance
, POLLIN
))) {
507 return MEMCACHED_IN_PROGRESS
;
511 case ENOTCONN
: // Programmer Error
516 assert_msg(instance
->fd
!= INVALID_SOCKET
, "Invalid socket state");
522 return MEMCACHED_CONNECTION_FAILURE
; // We want this!
525 } while (data_read
> 0);
527 return MEMCACHED_CONNECTION_FAILURE
;
530 static bool _io_write(memcached_instance_st
*instance
, const void *buffer
, size_t length
,
531 bool with_flush
, size_t &written
) {
532 assert(instance
->fd
!= INVALID_SOCKET
);
533 assert(memcached_is_udp(instance
->root
) == false);
535 const char *buffer_ptr
= static_cast<const char *>(buffer
);
537 const size_t original_length
= length
;
541 size_t buffer_end
= MEMCACHED_MAX_BUFFER
;
542 size_t should_write
= buffer_end
- instance
->write_buffer_offset
;
543 should_write
= (should_write
< length
) ? should_write
: length
;
545 write_ptr
= instance
->write_buffer
+ instance
->write_buffer_offset
;
546 memcpy(write_ptr
, buffer_ptr
, should_write
);
547 instance
->write_buffer_offset
+= should_write
;
548 buffer_ptr
+= should_write
;
549 length
-= should_write
;
551 if (instance
->write_buffer_offset
== buffer_end
) {
552 WATCHPOINT_ASSERT(instance
->fd
!= INVALID_SOCKET
);
554 memcached_return_t rc
;
555 if (io_flush(instance
, with_flush
, rc
) == false) {
556 written
= original_length
- length
;
563 memcached_return_t rc
;
564 WATCHPOINT_ASSERT(instance
->fd
!= INVALID_SOCKET
);
565 if (io_flush(instance
, with_flush
, rc
) == false) {
566 written
= original_length
- length
;
571 written
= original_length
- length
;
576 bool memcached_io_write(memcached_instance_st
*instance
) {
578 return _io_write(instance
, NULL
, 0, true, written
);
581 ssize_t
memcached_io_write(memcached_instance_st
*instance
, const void *buffer
, const size_t length
,
582 const bool with_flush
) {
585 if (_io_write(instance
, buffer
, length
, with_flush
, written
) == false) {
589 return ssize_t(written
);
592 bool memcached_io_writev(memcached_instance_st
*instance
, libmemcached_io_vector_st vector
[],
593 const size_t number_of
, const bool with_flush
) {
594 ssize_t complete_total
= 0;
597 for (size_t x
= 0; x
< number_of
; x
++, vector
++) {
598 complete_total
+= vector
->length
;
599 if (vector
->length
) {
601 if ((_io_write(instance
, vector
->buffer
, vector
->length
, false, written
)) == false) {
609 if (memcached_io_write(instance
) == false) {
614 return (complete_total
== total
);
617 void memcached_instance_st::start_close_socket() {
618 if (fd
!= INVALID_SOCKET
) {
619 shutdown(fd
, SHUT_WR
);
620 options
.is_shutting_down
= true;
624 void memcached_instance_st::reset_socket() {
625 if (fd
!= INVALID_SOCKET
) {
626 (void) closesocket(fd
);
631 void memcached_instance_st::close_socket() {
632 if (fd
!= INVALID_SOCKET
) {
633 int shutdown_options
= SHUT_RD
;
634 if (options
.is_shutting_down
== false) {
635 shutdown_options
= SHUT_RDWR
;
638 /* in case of death shutdown to avoid blocking at close() */
639 if (shutdown(fd
, shutdown_options
) == SOCKET_ERROR
and get_socket_errno() != ENOTCONN
) {
640 WATCHPOINT_NUMBER(fd
);
641 WATCHPOINT_ERRNO(get_socket_errno());
642 WATCHPOINT_ASSERT(get_socket_errno());
646 state
= MEMCACHED_SERVER_STATE_NEW
;
649 state
= MEMCACHED_SERVER_STATE_NEW
;
652 write_buffer_offset
= size_t(root
and memcached_is_udp(root
) ? UDP_DATAGRAM_HEADER_LENGTH
: 0);
653 read_buffer_length
= 0;
654 read_ptr
= read_buffer
;
655 options
.is_shutting_down
= false;
656 memcached_server_response_reset(this);
658 // We reset the version so that if we end up talking to a different server
659 // we don't have stale server version information.
660 major_version
= minor_version
= micro_version
= UINT8_MAX
;
663 memcached_instance_st
*memcached_io_get_readable_server(Memcached
*memc
, memcached_return_t
&) {
664 #define MAX_SERVERS_TO_POLL 100
665 struct pollfd fds
[MAX_SERVERS_TO_POLL
];
666 nfds_t host_index
= 0;
668 for (uint32_t x
= 0; x
< memcached_server_count(memc
) and host_index
< MAX_SERVERS_TO_POLL
; ++x
) {
669 memcached_instance_st
*instance
= memcached_instance_fetch(memc
, x
);
671 if (instance
->read_buffer_length
> 0) /* I have data in the buffer */ {
675 if (instance
->response_count() > 0) {
676 fds
[host_index
].events
= POLLIN
;
677 fds
[host_index
].revents
= 0;
678 fds
[host_index
].fd
= instance
->fd
;
683 if (host_index
< 2) {
684 /* We have 0 or 1 server with pending events.. */
685 for (uint32_t x
= 0; x
< memcached_server_count(memc
); ++x
) {
686 memcached_instance_st
*instance
= memcached_instance_fetch(memc
, x
);
688 if (instance
->response_count() > 0) {
696 int error
= poll(fds
, host_index
, memc
->poll_timeout
);
699 memcached_set_errno(*memc
, get_socket_errno(), MEMCACHED_AT
);
705 for (nfds_t x
= 0; x
< host_index
; ++x
) {
706 if (fds
[x
].revents
& POLLIN
) {
707 for (uint32_t y
= 0; y
< memcached_server_count(memc
); ++y
) {
708 memcached_instance_st
*instance
= memcached_instance_fetch(memc
, y
);
710 if (instance
->fd
== fds
[x
].fd
) {
722 Eventually we will just kill off the server with the problem.
724 void memcached_io_reset(memcached_instance_st
*instance
) {
725 memcached_quit_server(instance
, true);
729 * Read a given number of bytes from the server and place it into a specific
730 * buffer. Reset the IO channel on this server if an error occurs.
732 memcached_return_t
memcached_safe_read(memcached_instance_st
*instance
, void *dta
,
735 char *data
= static_cast<char *>(dta
);
737 while (offset
< size
) {
739 memcached_return_t rc
;
742 memcached_continue(rc
= memcached_io_read(instance
, data
+ offset
, size
- offset
, nread
))) {
745 if (memcached_failed(rc
)) {
749 offset
+= size_t(nread
);
752 return MEMCACHED_SUCCESS
;
755 memcached_return_t
memcached_io_readline(memcached_instance_st
*instance
, char *buffer_ptr
,
756 size_t size
, size_t &total_nr
) {
758 bool line_complete
= false;
760 while (line_complete
== false) {
761 if (instance
->read_buffer_length
== 0) {
763 * We don't have any data in the buffer, so let's fill the read
764 * buffer. Call the standard read function to avoid duplicating
768 memcached_return_t rc
= memcached_io_read(instance
, buffer_ptr
, 1, nread
);
769 if (memcached_failed(rc
) and rc
== MEMCACHED_IN_PROGRESS
) {
770 memcached_quit_server(instance
, true);
771 return memcached_set_error(*instance
, rc
, MEMCACHED_AT
);
772 } else if (memcached_failed(rc
)) {
776 if (*buffer_ptr
== '\n') {
777 line_complete
= true;
784 /* Now let's look in the buffer and copy as we go! */
785 while (instance
->read_buffer_length
and total_nr
< size
and line_complete
== false) {
786 *buffer_ptr
= *instance
->read_ptr
;
787 if (*buffer_ptr
== '\n') {
788 line_complete
= true;
790 --instance
->read_buffer_length
;
791 ++instance
->read_ptr
;
796 if (total_nr
== size
) {
797 return MEMCACHED_PROTOCOL_ERROR
;
801 return MEMCACHED_SUCCESS
;