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"
17 #include "p9y/poll.hpp"
19 void initialize_binary_request(memcached_instance_st
*server
,
20 protocol_binary_request_header
&header
) {
22 header
.request
.magic
= PROTOCOL_BINARY_REQ
;
23 header
.request
.opaque
= htons(server
->request_id
);
26 enum memc_read_or_write
{ MEM_READ
, MEM_WRITE
};
29 * Try to fill the input buffer for a server with as much
32 * @param instance the server to pack
34 static bool repack_input_buffer(memcached_instance_st
*instance
) {
35 if (instance
->read_ptr
!= instance
->read_buffer
) {
36 /* Move all of the data to the beginning of the buffer so
37 ** that we can fit more data into the buffer...
39 memmove(instance
->read_buffer
, instance
->read_ptr
, instance
->read_buffer_length
);
40 instance
->read_ptr
= instance
->read_buffer
;
43 /* There is room in the buffer, try to fill it! */
44 if (instance
->read_buffer_length
!= MEMCACHED_MAX_BUFFER
) {
46 /* Just try a single read to grab what's available */
48 if ((nr
= ::recv(instance
->fd
, instance
->read_ptr
+ instance
->read_buffer_length
,
49 MEMCACHED_MAX_BUFFER
- instance
->read_buffer_length
, MSG_NOSIGNAL
))
53 memcached_set_error(*instance
, MEMCACHED_CONNECTION_FAILURE
, MEMCACHED_AT
);
55 switch (get_socket_errno()) {
59 #if EWOULDBLOCK != EAGAIN
66 break; // No IO is fine, we can just move on
69 memcached_set_errno(*instance
, get_socket_errno(), MEMCACHED_AT
);
74 } else // We read data, append to our read buffer
76 instance
->read_buffer_length
+= size_t(nr
);
87 * If the we have callbacks connected to this server structure
88 * we may start process the input queue and fire the callbacks
89 * for the incomming messages. This function is _only_ called
90 * when the input buffer is full, so that we _know_ that we have
91 * at least _one_ message to process.
93 * @param instance the server to star processing iput messages for
94 * @return true if we processed anything, false otherwise
96 static bool process_input_buffer(memcached_instance_st
*instance
) {
98 ** We might be able to process some of the response messages if we
99 ** have a callback set up
101 if (instance
->root
->callbacks
) {
103 * We might have responses... try to read them out and fire
106 memcached_callback_st cb
= *instance
->root
->callbacks
;
108 memcached_set_processing_input((Memcached
*) instance
->root
, true);
110 char buffer
[MEMCACHED_DEFAULT_COMMAND_SIZE
];
111 Memcached
*root
= (Memcached
*) instance
->root
;
112 memcached_return_t error
= memcached_response(instance
, buffer
, sizeof(buffer
), &root
->result
);
114 memcached_set_processing_input(root
, false);
116 if (error
== MEMCACHED_SUCCESS
) {
117 for (unsigned int x
= 0; x
< cb
.number_of_callback
; x
++) {
118 error
= (*cb
.callback
[x
])(instance
->root
, &root
->result
, cb
.context
);
119 if (error
!= MEMCACHED_SUCCESS
) {
124 /* @todo what should I do with the error message??? */
126 /* @todo what should I do with other error messages?? */
133 static memcached_return_t
io_wait(memcached_instance_st
*instance
, const short events
) {
135 ** We are going to block on write, but at least on Solaris we might block
136 ** on write if we haven't read anything from our input buffer..
137 ** Try to purge the input buffer if we don't do any flow control in the
138 ** application layer (just sending a lot of data etc)
139 ** The test is moved down in the purge function to avoid duplication of
142 if (events
& POLLOUT
) {
143 if (memcached_purge(instance
) == false) {
144 return MEMCACHED_FAILURE
;
149 fds
.fd
= instance
->fd
;
153 if (fds
.events
& POLLOUT
) /* write */ {
154 instance
->io_wait_count
.write
++;
156 instance
->io_wait_count
.read
++;
159 if (instance
->root
->poll_timeout
160 == 0) // Mimic 0 causes timeout behavior (not all platforms do this)
162 return memcached_set_error(*instance
, MEMCACHED_TIMEOUT
, MEMCACHED_AT
,
163 memcached_literal_param("poll_timeout() was set to zero"));
167 while (--loop_max
) // While loop is for ERESTART or EINTR
169 int active_fd
= poll(&fds
, 1, instance
->root
->poll_timeout
);
171 if (active_fd
>= 1) {
172 assert_msg(active_fd
== 1, "poll() returned an unexpected number of active file descriptors");
173 if (fds
.revents
& POLLIN
or fds
.revents
& POLLOUT
) {
174 return MEMCACHED_SUCCESS
;
177 if (fds
.revents
& POLLHUP
) {
178 return memcached_set_error(*instance
, MEMCACHED_CONNECTION_FAILURE
, MEMCACHED_AT
,
179 memcached_literal_param("poll() detected hang up"));
182 if (fds
.revents
& POLLERR
) {
183 int local_errno
= EINVAL
;
185 socklen_t len
= sizeof(err
);
186 if (getsockopt(instance
->fd
, SOL_SOCKET
, SO_ERROR
, (char *) &err
, &len
) == 0) {
187 if (err
== 0) // treat this as EINTR
193 memcached_quit_server(instance
, true);
194 return memcached_set_errno(*instance
, local_errno
, MEMCACHED_AT
,
195 memcached_literal_param("poll() returned POLLHUP"));
198 return memcached_set_error(
199 *instance
, MEMCACHED_FAILURE
, MEMCACHED_AT
,
200 memcached_literal_param("poll() returned a value that was not dealt with"));
203 if (active_fd
== 0) {
204 return memcached_set_error(*instance
, MEMCACHED_TIMEOUT
, MEMCACHED_AT
,
205 memcached_literal_param("No active_fd were found"));
208 // Only an error should result in this code being called.
209 int local_errno
= get_socket_errno(); // We cache in case memcached_quit_server() modifies errno
210 assert_msg(active_fd
== -1, "poll() returned an unexpected value");
211 switch (local_errno
) {
220 memcached_set_error(*instance
, MEMCACHED_MEMORY_ALLOCATION_FAILURE
, MEMCACHED_AT
);
224 memcached_set_error(*instance
, MEMCACHED_MEMORY_ALLOCATION_FAILURE
, MEMCACHED_AT
,
225 memcached_literal_param(
226 "RLIMIT_NOFILE exceeded, or if OSX the timeout value was invalid"));
230 memcached_set_errno(*instance
, local_errno
, MEMCACHED_AT
, memcached_literal_param("poll"));
236 memcached_quit_server(instance
, true);
238 if (memcached_has_error(instance
)) {
239 return memcached_instance_error_return(instance
);
242 return memcached_set_error(
243 *instance
, MEMCACHED_CONNECTION_FAILURE
, MEMCACHED_AT
,
244 memcached_literal_param("number of attempts to call io_wait() failed"));
247 static bool io_flush(memcached_instance_st
*instance
, const bool with_flush
,
248 memcached_return_t
&error
) {
250 ** We might want to purge the input buffer if we haven't consumed
251 ** any output yet... The test for the limits is the purge is inline
252 ** in the purge function to avoid duplicating the logic..
255 WATCHPOINT_ASSERT(instance
->fd
!= INVALID_SOCKET
);
257 if (memcached_purge(instance
) == false) {
261 char *local_write_ptr
= instance
->write_buffer
;
262 size_t write_length
= instance
->write_buffer_offset
;
264 error
= MEMCACHED_SUCCESS
;
266 WATCHPOINT_ASSERT(instance
->fd
!= INVALID_SOCKET
);
268 /* Looking for memory overflows */
270 if (write_length
== MEMCACHED_MAX_BUFFER
)
271 WATCHPOINT_ASSERT(instance
->write_buffer
== local_write_ptr
);
272 WATCHPOINT_ASSERT((instance
->write_buffer
+ MEMCACHED_MAX_BUFFER
)
273 >= (local_write_ptr
+ write_length
));
276 while (write_length
) {
277 WATCHPOINT_ASSERT(instance
->fd
!= INVALID_SOCKET
);
278 WATCHPOINT_ASSERT(write_length
> 0);
282 flags
= MSG_NOSIGNAL
;
284 flags
= MSG_NOSIGNAL
| MSG_MORE
;
287 ssize_t sent_length
= ::send(instance
->fd
, local_write_ptr
, write_length
, flags
);
288 int local_errno
= get_socket_errno(); // We cache in case memcached_quit_server() modifies errno
290 if (sent_length
== SOCKET_ERROR
) {
291 #if 0 // @todo I should look at why we hit this bit of code hard frequently
292 WATCHPOINT_ERRNO(get_socket_errno());
293 WATCHPOINT_NUMBER(get_socket_errno());
295 switch (get_socket_errno()) {
299 #if EWOULDBLOCK != EAGAIN
304 * We may be blocked on write because the input buffer
305 * is full. Let's check if we have room in our input
306 * buffer for more data and retry the write before
309 if (repack_input_buffer(instance
) or process_input_buffer(instance
)) {
313 memcached_return_t rc
= io_wait(instance
, POLLOUT
);
314 if (memcached_success(rc
)) {
316 } else if (rc
== MEMCACHED_TIMEOUT
) {
320 memcached_quit_server(instance
, true);
321 error
= memcached_set_errno(*instance
, local_errno
, MEMCACHED_AT
);
327 memcached_quit_server(instance
, true);
328 error
= memcached_set_errno(*instance
, local_errno
, MEMCACHED_AT
);
329 WATCHPOINT_ASSERT(instance
->fd
== INVALID_SOCKET
);
334 instance
->io_bytes_sent
+= uint32_t(sent_length
);
336 local_write_ptr
+= sent_length
;
337 write_length
-= uint32_t(sent_length
);
340 WATCHPOINT_ASSERT(write_length
== 0);
341 instance
->write_buffer_offset
= 0;
346 memcached_return_t
memcached_io_wait_for_write(memcached_instance_st
*instance
) {
347 return io_wait(instance
, POLLOUT
);
350 memcached_return_t
memcached_io_wait_for_read(memcached_instance_st
*instance
) {
351 return io_wait(instance
, POLLIN
);
354 static memcached_return_t
_io_fill(memcached_instance_st
*instance
) {
357 data_read
= ::recv(instance
->fd
, instance
->read_buffer
, MEMCACHED_MAX_BUFFER
, MSG_NOSIGNAL
);
358 int local_errno
= get_socket_errno(); // We cache in case memcached_quit_server() modifies errno
360 if (data_read
== SOCKET_ERROR
) {
361 switch (get_socket_errno()) {
362 case EINTR
: // We just retry
365 case ETIMEDOUT
: // OSX
366 #if EWOULDBLOCK != EAGAIN
374 memcached_return_t io_wait_ret
;
375 if (memcached_success(io_wait_ret
= io_wait(instance
, POLLIN
))) {
384 case ENOTCONN
: // Programmer Error
385 WATCHPOINT_ASSERT(0);
388 WATCHPOINT_ASSERT(0);
391 assert_msg(instance
->fd
!= INVALID_SOCKET
, "Programmer error, invalid socket");
397 memcached_quit_server(instance
, true);
398 memcached_set_errno(*instance
, local_errno
, MEMCACHED_AT
);
402 return memcached_instance_error_return(instance
);
403 } else if (data_read
== 0) {
405 EOF. Any data received so far is incomplete
406 so discard it. This always reads by byte in case of TCP
407 and protocol enforcement happens at memcached_response()
408 looking for '\n'. We do not care for UDB which requests 8 bytes
409 at once. Generally, this means that connection went away. Since
410 for blocking I/O we do not return 0 and for non-blocking case
411 it will return EGAIN if data is not immediatly available.
413 memcached_quit_server(instance
, true);
414 return memcached_set_error(
415 *instance
, MEMCACHED_CONNECTION_FAILURE
, MEMCACHED_AT
,
416 memcached_literal_param("::rec() returned zero, server has disconnected"));
418 instance
->io_wait_count
._bytes_read
+= data_read
;
419 } while (data_read
<= 0);
421 instance
->io_bytes_sent
= 0;
422 instance
->read_buffer_length
= (size_t) data_read
;
423 instance
->read_ptr
= instance
->read_buffer
;
425 return MEMCACHED_SUCCESS
;
428 memcached_return_t
memcached_io_read(memcached_instance_st
*instance
, void *buffer
, size_t length
,
430 assert(memcached_is_udp(instance
->root
) == false);
433 "Programmer error, memcached_io_read() recieved an invalid Instance"); // Programmer error
434 char *buffer_ptr
= static_cast<char *>(buffer
);
436 if (instance
->fd
== INVALID_SOCKET
) {
438 assert_msg(int(instance
->state
) <= int(MEMCACHED_SERVER_STATE_ADDRINFO
), "Programmer error, invalid socket state");
440 return MEMCACHED_CONNECTION_FAILURE
;
444 if (instance
->read_buffer_length
== 0) {
445 memcached_return_t io_fill_ret
;
446 if (memcached_fatal(io_fill_ret
= _io_fill(instance
))) {
454 (length
> instance
->read_buffer_length
) ? instance
->read_buffer_length
: length
;
456 memcpy(buffer_ptr
, instance
->read_ptr
, difference
);
457 length
-= difference
;
458 instance
->read_ptr
+= difference
;
459 instance
->read_buffer_length
-= difference
;
460 buffer_ptr
+= difference
;
462 *buffer_ptr
= *instance
->read_ptr
;
463 instance
->read_ptr
++;
464 instance
->read_buffer_length
--;
470 nread
= ssize_t(buffer_ptr
- (char *) buffer
);
472 return MEMCACHED_SUCCESS
;
475 memcached_return_t
memcached_io_slurp(memcached_instance_st
*instance
) {
476 assert_msg(instance
, "Programmer error, invalid Instance");
477 assert(memcached_is_udp(instance
->root
) == false);
479 if (instance
->fd
== INVALID_SOCKET
) {
480 assert_msg(int(instance
->state
) <= int(MEMCACHED_SERVER_STATE_ADDRINFO
),
481 "Invalid socket state");
482 return MEMCACHED_CONNECTION_FAILURE
;
486 char buffer
[MEMCACHED_MAX_BUFFER
];
488 data_read
= ::recv(instance
->fd
, instance
->read_buffer
, sizeof(buffer
), MSG_NOSIGNAL
);
489 if (data_read
== SOCKET_ERROR
) {
490 switch (get_socket_errno()) {
491 case EINTR
: // We just retry
494 case ETIMEDOUT
: // OSX
495 #if EWOULDBLOCK != EAGAIN
502 if (memcached_success(io_wait(instance
, POLLIN
))) {
505 return MEMCACHED_IN_PROGRESS
;
509 case ENOTCONN
: // Programmer Error
514 assert_msg(instance
->fd
!= INVALID_SOCKET
, "Invalid socket state");
520 return MEMCACHED_CONNECTION_FAILURE
; // We want this!
523 } while (data_read
> 0);
525 return MEMCACHED_CONNECTION_FAILURE
;
528 static bool _io_write(memcached_instance_st
*instance
, const void *buffer
, size_t length
,
529 bool with_flush
, size_t &written
) {
530 assert(instance
->fd
!= INVALID_SOCKET
);
531 assert(memcached_is_udp(instance
->root
) == false);
533 const char *buffer_ptr
= static_cast<const char *>(buffer
);
535 const size_t original_length
= length
;
539 size_t buffer_end
= MEMCACHED_MAX_BUFFER
;
540 size_t should_write
= buffer_end
- instance
->write_buffer_offset
;
541 should_write
= (should_write
< length
) ? should_write
: length
;
543 write_ptr
= instance
->write_buffer
+ instance
->write_buffer_offset
;
544 memcpy(write_ptr
, buffer_ptr
, should_write
);
545 instance
->write_buffer_offset
+= should_write
;
546 buffer_ptr
+= should_write
;
547 length
-= should_write
;
549 if (instance
->write_buffer_offset
== buffer_end
) {
550 WATCHPOINT_ASSERT(instance
->fd
!= INVALID_SOCKET
);
552 memcached_return_t rc
;
553 if (io_flush(instance
, with_flush
, rc
) == false) {
554 written
= original_length
- length
;
561 memcached_return_t rc
;
562 WATCHPOINT_ASSERT(instance
->fd
!= INVALID_SOCKET
);
563 if (io_flush(instance
, with_flush
, rc
) == false) {
564 written
= original_length
- length
;
569 written
= original_length
- length
;
574 bool memcached_io_write(memcached_instance_st
*instance
) {
576 return _io_write(instance
, NULL
, 0, true, written
);
579 ssize_t
memcached_io_write(memcached_instance_st
*instance
, const void *buffer
, const size_t length
,
580 const bool with_flush
) {
583 if (_io_write(instance
, buffer
, length
, with_flush
, written
) == false) {
587 return ssize_t(written
);
590 bool memcached_io_writev(memcached_instance_st
*instance
, libmemcached_io_vector_st vector
[],
591 const size_t number_of
, const bool with_flush
) {
592 ssize_t complete_total
= 0;
595 for (size_t x
= 0; x
< number_of
; x
++, vector
++) {
596 complete_total
+= vector
->length
;
597 if (vector
->length
) {
599 if ((_io_write(instance
, vector
->buffer
, vector
->length
, false, written
)) == false) {
607 if (memcached_io_write(instance
) == false) {
612 return (complete_total
== total
);
615 void memcached_instance_st::start_close_socket() {
616 if (fd
!= INVALID_SOCKET
) {
617 shutdown(fd
, SHUT_WR
);
618 options
.is_shutting_down
= true;
622 void memcached_instance_st::reset_socket() {
623 if (fd
!= INVALID_SOCKET
) {
624 (void) closesocket(fd
);
629 void memcached_instance_st::close_socket() {
630 if (fd
!= INVALID_SOCKET
) {
631 int shutdown_options
= SHUT_RD
;
632 if (options
.is_shutting_down
== false) {
633 shutdown_options
= SHUT_RDWR
;
636 /* in case of death shutdown to avoid blocking at close() */
637 if (shutdown(fd
, shutdown_options
) == SOCKET_ERROR
and get_socket_errno() != ENOTCONN
) {
638 WATCHPOINT_NUMBER(fd
);
639 WATCHPOINT_ERRNO(get_socket_errno());
640 WATCHPOINT_ASSERT(get_socket_errno());
644 state
= MEMCACHED_SERVER_STATE_NEW
;
647 state
= MEMCACHED_SERVER_STATE_NEW
;
650 write_buffer_offset
= size_t(root
and memcached_is_udp(root
) ? UDP_DATAGRAM_HEADER_LENGTH
: 0);
651 read_buffer_length
= 0;
652 read_ptr
= read_buffer
;
653 options
.is_shutting_down
= false;
654 memcached_server_response_reset(this);
656 // We reset the version so that if we end up talking to a different server
657 // we don't have stale server version information.
658 major_version
= minor_version
= micro_version
= UINT8_MAX
;
661 memcached_instance_st
*memcached_io_get_readable_server(Memcached
*memc
, memcached_return_t
&) {
662 #define MAX_SERVERS_TO_POLL 100
663 struct pollfd fds
[MAX_SERVERS_TO_POLL
];
664 nfds_t host_index
= 0;
666 for (uint32_t x
= 0; x
< memcached_server_count(memc
) and host_index
< MAX_SERVERS_TO_POLL
; ++x
) {
667 memcached_instance_st
*instance
= memcached_instance_fetch(memc
, x
);
669 if (instance
->read_buffer_length
> 0) /* I have data in the buffer */ {
673 if (instance
->response_count() > 0) {
674 fds
[host_index
].events
= POLLIN
;
675 fds
[host_index
].revents
= 0;
676 fds
[host_index
].fd
= instance
->fd
;
681 if (host_index
< 2) {
682 /* We have 0 or 1 server with pending events.. */
683 for (uint32_t x
= 0; x
< memcached_server_count(memc
); ++x
) {
684 memcached_instance_st
*instance
= memcached_instance_fetch(memc
, x
);
686 if (instance
->response_count() > 0) {
694 int error
= poll(fds
, host_index
, memc
->poll_timeout
);
697 memcached_set_errno(*memc
, get_socket_errno(), MEMCACHED_AT
);
703 for (nfds_t x
= 0; x
< host_index
; ++x
) {
704 if (fds
[x
].revents
& POLLIN
) {
705 for (uint32_t y
= 0; y
< memcached_server_count(memc
); ++y
) {
706 memcached_instance_st
*instance
= memcached_instance_fetch(memc
, y
);
708 if (instance
->fd
== fds
[x
].fd
) {
720 Eventually we will just kill off the server with the problem.
722 void memcached_io_reset(memcached_instance_st
*instance
) {
723 memcached_quit_server(instance
, true);
727 * Read a given number of bytes from the server and place it into a specific
728 * buffer. Reset the IO channel on this server if an error occurs.
730 memcached_return_t
memcached_safe_read(memcached_instance_st
*instance
, void *dta
,
733 char *data
= static_cast<char *>(dta
);
735 while (offset
< size
) {
737 memcached_return_t rc
;
740 memcached_continue(rc
= memcached_io_read(instance
, data
+ offset
, size
- offset
, nread
))) {
743 if (memcached_failed(rc
)) {
747 offset
+= size_t(nread
);
750 return MEMCACHED_SUCCESS
;
753 memcached_return_t
memcached_io_readline(memcached_instance_st
*instance
, char *buffer_ptr
,
754 size_t size
, size_t &total_nr
) {
756 bool line_complete
= false;
758 while (line_complete
== false) {
759 if (instance
->read_buffer_length
== 0) {
761 * We don't have any data in the buffer, so let's fill the read
762 * buffer. Call the standard read function to avoid duplicating
766 memcached_return_t rc
= memcached_io_read(instance
, buffer_ptr
, 1, nread
);
767 if (memcached_failed(rc
) and rc
== MEMCACHED_IN_PROGRESS
) {
768 memcached_quit_server(instance
, true);
769 return memcached_set_error(*instance
, rc
, MEMCACHED_AT
);
770 } else if (memcached_failed(rc
)) {
774 if (*buffer_ptr
== '\n') {
775 line_complete
= true;
782 /* Now let's look in the buffer and copy as we go! */
783 while (instance
->read_buffer_length
and total_nr
< size
and line_complete
== false) {
784 *buffer_ptr
= *instance
->read_ptr
;
785 if (*buffer_ptr
== '\n') {
786 line_complete
= true;
788 --instance
->read_buffer_length
;
789 ++instance
->read_ptr
;
794 if (total_nr
== size
) {
795 return MEMCACHED_PROTOCOL_ERROR
;
799 return MEMCACHED_SUCCESS
;