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git.ipfire.org Git - thirdparty/squid.git/blob - src/comm/Read.cc
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2 * Copyright (C) 1996-2017 The Squid Software Foundation and contributors
4 * Squid software is distributed under GPLv2+ license and includes
5 * contributions from numerous individuals and organizations.
6 * Please see the COPYING and CONTRIBUTORS files for details.
9 /* DEBUG: section 05 Socket Functions */
13 #include "comm/IoCallback.h"
14 #include "comm/Loops.h"
15 #include "comm/Read.h"
16 #include "comm_internal.h"
17 #include "CommCalls.h"
21 #include "sbuf/SBuf.h"
22 #include "StatCounters.h"
24 // Does comm check this fd for read readiness?
25 // Note that when comm is not monitoring, there can be a pending callback
26 // call, which may resume comm monitoring once fired.
28 Comm::MonitorsRead(int fd
)
30 assert(isOpen(fd
) && COMMIO_FD_READCB(fd
) != NULL
);
31 // Being active is usually the same as monitoring because we always
32 // start monitoring the FD when we configure Comm::IoCallback for I/O
33 // and we usually configure Comm::IoCallback for I/O when we starting
34 // monitoring a FD for reading.
35 return COMMIO_FD_READCB(fd
)->active();
39 Comm::Read(const Comm::ConnectionPointer
&conn
, AsyncCall::Pointer
&callback
)
41 // TODO: move comm_read_base() internals into here
42 // when comm_read() char* API is no longer needed
43 comm_read_base(conn
, NULL
, 0, callback
);
48 * If a buffer is given the callback is scheduled when the read
49 * completes, on error, or on file descriptor close.
51 * If no buffer (NULL) is given the callback is scheduled when
52 * the socket FD is ready for a read(2)/recv(2).
55 comm_read_base(const Comm::ConnectionPointer
&conn
, char *buf
, int size
, AsyncCall::Pointer
&callback
)
57 debugs(5, 5, "comm_read, queueing read for " << conn
<< "; asynCall " << callback
);
59 /* Make sure we are open and not closing */
60 assert(Comm::IsConnOpen(conn
));
61 assert(!fd_table
[conn
->fd
].closing());
62 Comm::IoCallback
*ccb
= COMMIO_FD_READCB(conn
->fd
);
64 // Make sure we are either not reading or just passively monitoring.
65 // Active/passive conflicts are OK and simply cancel passive monitoring.
67 // if the assertion below fails, we have an active comm_read conflict
68 assert(fd_table
[conn
->fd
].halfClosedReader
!= NULL
);
69 commStopHalfClosedMonitor(conn
->fd
);
70 assert(!ccb
->active());
75 ccb
->setCallback(Comm::IOCB_READ
, callback
, (char *)buf
, NULL
, size
);
76 Comm::SetSelect(conn
->fd
, COMM_SELECT_READ
, Comm::HandleRead
, ccb
, 0);
80 Comm::ReadNow(CommIoCbParams
¶ms
, SBuf
&buf
)
83 ++ statCounter
.syscalls
.sock
.reads
;
84 SBuf::size_type sz
= buf
.spaceSize();
85 if (params
.size
> 0 && params
.size
< sz
)
87 char *inbuf
= buf
.rawAppendStart(sz
);
89 const int retval
= FD_READ_METHOD(params
.conn
->fd
, inbuf
, sz
);
90 params
.xerrno
= errno
;
92 debugs(5, 3, params
.conn
<< ", size " << sz
<< ", retval " << retval
<< ", errno " << params
.xerrno
);
94 if (retval
> 0) { // data read most common case
95 buf
.rawAppendFinish(inbuf
, retval
);
96 fd_bytes(params
.conn
->fd
, retval
, FD_READ
);
97 params
.flag
= Comm::OK
;
100 } else if (retval
== 0) { // remote closure (somewhat less) common
101 // Note - read 0 == socket EOF, which is a valid read.
102 params
.flag
= Comm::ENDFILE
;
104 } else if (retval
< 0) { // connection errors are worst-case
105 debugs(5, 3, params
.conn
<< " Comm::COMM_ERROR: " << xstrerr(params
.xerrno
));
106 if (ignoreErrno(params
.xerrno
))
107 params
.flag
= Comm::INPROGRESS
;
109 params
.flag
= Comm::COMM_ERROR
;
116 * Handle an FD which is ready for read(2).
118 * If there is no provided buffer to fill call the callback.
120 * Otherwise attempt a read into the provided buffer.
121 * If the read attempt succeeds or fails, call the callback.
122 * Else, wait for another IO notification.
125 Comm::HandleRead(int fd
, void *data
)
127 Comm::IoCallback
*ccb
= (Comm::IoCallback
*) data
;
129 assert(data
== COMMIO_FD_READCB(fd
));
130 assert(ccb
->active());
132 // Without a buffer, just call back.
133 // The callee may ReadMore() to get the data.
135 ccb
->finish(Comm::OK
, 0);
139 /* For legacy callers : Attempt a read */
140 // Keep in sync with Comm::ReadNow()!
141 ++ statCounter
.syscalls
.sock
.reads
;
142 int xerrno
= errno
= 0;
143 int retval
= FD_READ_METHOD(fd
, ccb
->buf
, ccb
->size
);
145 debugs(5, 3, "FD " << fd
<< ", size " << ccb
->size
<< ", retval " << retval
<< ", errno " << xerrno
);
147 /* See if we read anything */
148 /* Note - read 0 == socket EOF, which is a valid read */
150 fd_bytes(fd
, retval
, FD_READ
);
151 ccb
->offset
= retval
;
152 ccb
->finish(Comm::OK
, 0);
154 } else if (retval
< 0 && !ignoreErrno(xerrno
)) {
155 debugs(5, 3, "comm_read_try: scheduling Comm::COMM_ERROR");
157 ccb
->finish(Comm::COMM_ERROR
, xerrno
);
161 /* Nope, register for some more IO */
162 Comm::SetSelect(fd
, COMM_SELECT_READ
, Comm::HandleRead
, data
, 0);
166 * Cancel a pending read. Assert that we have the right parameters,
167 * and that there are no pending read events!
169 * XXX: We do not assert that there are no pending read events and
170 * with async calls it becomes even more difficult.
171 * The whole interface should be reworked to do callback->cancel()
172 * instead of searching for places where the callback may be stored and
173 * updating the state of those places.
175 * AHC Don't call the comm handlers?
178 comm_read_cancel(int fd
, IOCB
*callback
, void *data
)
181 debugs(5, 4, "fails: FD " << fd
<< " closed");
185 Comm::IoCallback
*cb
= COMMIO_FD_READCB(fd
);
186 // TODO: is "active" == "monitors FD"?
188 debugs(5, 4, "fails: FD " << fd
<< " inactive");
192 typedef CommCbFunPtrCallT
<CommIoCbPtrFun
> Call
;
193 Call
*call
= dynamic_cast<Call
*>(cb
->callback
.getRaw());
195 debugs(5, 4, "fails: FD " << fd
<< " lacks callback");
199 call
->cancel("old comm_read_cancel");
201 typedef CommIoCbParams Params
;
202 const Params
¶ms
= GetCommParams
<Params
>(cb
->callback
);
204 /* Ok, we can be reasonably sure we won't lose any data here! */
205 assert(call
->dialer
.handler
== callback
);
206 assert(params
.data
== data
);
208 /* Delete the callback */
209 cb
->cancel("old comm_read_cancel");
211 /* And the IO event */
212 Comm::SetSelect(fd
, COMM_SELECT_READ
, NULL
, NULL
, 0);
216 Comm::ReadCancel(int fd
, AsyncCall::Pointer
&callback
)
218 callback
->cancel("comm_read_cancel");
221 debugs(5, 4, "fails: FD " << fd
<< " closed");
225 Comm::IoCallback
*cb
= COMMIO_FD_READCB(fd
);
228 debugs(5, 4, "fails: FD " << fd
<< " inactive");
232 AsyncCall::Pointer call
= cb
->callback
;
234 /* Ok, we can be reasonably sure we won't lose any data here! */
235 assert(call
== callback
);
237 /* Delete the callback */
238 cb
->cancel("comm_read_cancel");
240 /* And the IO event */
241 Comm::SetSelect(fd
, COMM_SELECT_READ
, NULL
, NULL
, 0);