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git.ipfire.org Git - thirdparty/squid.git/blob - src/unlinkd.cc
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2 * Copyright (C) 1996-2016 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 02 Unlink Daemon */
18 #include "SquidConfig.h"
20 #include "SquidTime.h"
21 #include "StatCounters.h"
22 #include "store/Disk.h"
26 /* This code gets linked to Squid */
28 static int unlinkd_wfd
= -1;
29 static int unlinkd_rfd
= -1;
34 #define UNLINKD_QUEUE_LIMIT 20
37 unlinkdUnlink(const char *path
)
42 static int queuelen
= 0;
44 if (unlinkd_wfd
< 0) {
45 debug_trap("unlinkdUnlink: unlinkd_wfd < 0");
51 * If the queue length is greater than our limit, then we pause
52 * for a small amount of time, hoping that unlinkd has some
53 * feedback for us. Maybe it just needs a slice of the CPU's
56 if (queuelen
>= UNLINKD_QUEUE_LIMIT
) {
57 #if defined(USE_EPOLL) || defined(USE_KQUEUE) || defined(USE_DEVPOLL)
60 * We can't use fd_set when using epoll() or kqueue(). In
61 * these cases we block for 10 ms.
67 * When we can use select, block for up to 100 ms.
72 FD_SET(unlinkd_rfd
, &R
);
75 select(unlinkd_rfd
+ 1, &R
, NULL
, NULL
, &to
);
80 * If there is at least one outstanding unlink request, then
81 * try to read a response. If there's nothing to read we'll
82 * get an EWOULDBLOCK or whatever. If we get a response, then
83 * decrement the queue size by the number of newlines read.
89 bytes_read
= read(unlinkd_rfd
, rbuf
, 511);
92 rbuf
[bytes_read
] = '\0';
94 for (i
= 0; i
< bytes_read
; ++i
)
98 assert(queuelen
>= 0);
103 assert(l
< MAXPATHLEN
);
104 xstrncpy(buf
, path
, MAXPATHLEN
);
107 bytes_written
= write(unlinkd_wfd
, buf
, l
);
109 if (bytes_written
< 0) {
111 debugs(2, DBG_IMPORTANT
, "unlinkdUnlink: write FD " << unlinkd_wfd
<< " failed: " << xstrerr(xerrno
));
114 } else if (bytes_written
!= l
) {
115 debugs(2, DBG_IMPORTANT
, "unlinkdUnlink: FD " << unlinkd_wfd
<< " only wrote " << bytes_written
<< " of " << l
<< " bytes");
120 ++statCounter
.unlink
.requests
;
122 * Increment this syscalls counter here, even though the syscall
123 * is executed by the helper process. We try to be consistent
124 * in counting unlink operations.
126 ++statCounter
.syscalls
.disk
.unlinks
;
135 if (unlinkd_wfd
> -1) {
136 debugs(2, DBG_IMPORTANT
, "Closing unlinkd pipe on FD " << unlinkd_wfd
);
137 shutdown(unlinkd_wfd
, SD_BOTH
);
138 comm_close(unlinkd_wfd
);
140 if (unlinkd_wfd
!= unlinkd_rfd
)
141 comm_close(unlinkd_rfd
);
149 if (WaitForSingleObject(hIpc
, 5000) != WAIT_OBJECT_0
) {
151 debugs(2, DBG_IMPORTANT
, "unlinkdClose: WARNING: (unlinkd," << pid
<< "d) didn't exit in 5 seconds");
163 debugs(2, DBG_IMPORTANT
, "Closing unlinkd pipe on FD " << unlinkd_wfd
);
165 file_close(unlinkd_wfd
);
167 if (unlinkd_wfd
!= unlinkd_rfd
)
168 file_close(unlinkd_rfd
);
180 // we should start unlinkd if there are any cache_dirs using it
181 for (int i
= 0; i
< Config
.cacheSwap
.n_configured
; ++i
) {
182 const RefCount
<SwapDir
> sd
= Config
.cacheSwap
.swapDirs
[i
];
183 if (sd
->unlinkdUseful())
193 if (unlinkd_wfd
>= 0)
194 return; // unlinkd already started
197 Ip::Address localhost
;
199 args
[0] = "(unlinkd)";
201 localhost
.setLocalhost();
204 #if USE_POLL && _SQUID_OSF_
205 /* pipes and poll() don't get along on DUNIX -DW */
207 #elif _SQUID_WINDOWS_
208 /* select() will fail on a pipe */
211 /* We currently need to use FIFO.. see below */
214 Config
.Program
.unlinkd
,
223 fatal("Failed to create unlinkd subprocess");
227 fd_note(unlinkd_wfd
, "squid -> unlinkd");
229 fd_note(unlinkd_rfd
, "unlinkd -> squid");
231 commUnsetFdTimeout(unlinkd_rfd
);
232 commUnsetFdTimeout(unlinkd_wfd
);
235 * unlinkd_rfd should already be non-blocking because of
236 * ipcCreate. We change unlinkd_wfd to blocking mode because
237 * we never want to lose an unlink request, and we don't have
238 * code to retry if we get EWOULDBLOCK. Unfortunately, we can
239 * do this only for the IPC_FIFO case.
241 assert(fd_table
[unlinkd_rfd
].flags
.nonblocking
);
243 if (FD_PIPE
== fd_table
[unlinkd_wfd
].type
)
244 commUnsetNonBlocking(unlinkd_wfd
);
246 debugs(2, DBG_IMPORTANT
, "Unlinkd pipe opened on FD " << unlinkd_wfd
);
250 debugs(2, 4, "Unlinkd handle: 0x" << std::hex
<< hIpc
<< std::dec
<< ", PID: " << pid
);
255 #endif /* USE_UNLINKD */