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git.ipfire.org Git - thirdparty/squid.git/blob - src/DiskIO/Mmapped/MmappedFile.cc
4 * DEBUG: section 47 Store Directory Routines
8 #include "DiskIO/IORequestor.h"
9 #include "DiskIO/Mmapped/MmappedFile.h"
10 #include "DiskIO/ReadRequest.h"
11 #include "DiskIO/WriteRequest.h"
14 CBDATA_CLASS_INIT(MmappedFile
);
16 // helper class to deal with mmap(2) offset alignment and other low-level specs
20 Mmapping(int fd
, size_t length
, int prot
, int flags
, off_t offset
);
23 void *map(); ///< calls mmap(2); returns usable buffer or nil on failure
24 bool unmap(); ///< unmaps previously mapped buffer, if any
27 const int fd
; ///< descriptor of the mmapped file
28 const size_t length
; ///< user-requested data length, needed for munmap
29 const int prot
; ///< mmap(2) "protection" flags
30 const int flags
; ///< other mmap(2) flags
31 const off_t offset
; ///< user-requested data offset
33 off_t delta
; ///< mapped buffer increment to hit user offset
34 void *buf
; ///< buffer returned by mmap, needed for munmap
39 MmappedFile::operator new(size_t sz
)
41 CBDATA_INIT_TYPE(MmappedFile
);
42 MmappedFile
*result
= cbdataAlloc(MmappedFile
);
43 /* Mark result as being owned - we want the refcounter to do the delete
49 MmappedFile::operator delete(void *address
)
51 MmappedFile
*t
= static_cast<MmappedFile
*>(address
);
55 MmappedFile::MmappedFile(char const *aPath
): fd(-1),
56 minOffset(0), maxOffset(-1), error_(false)
59 path_
= xstrdup(aPath
);
60 debugs(79,5, HERE
<< this << ' ' << path_
);
63 MmappedFile::~MmappedFile()
69 // XXX: almost a copy of BlockingFile::open
71 MmappedFile::open(int flags
, mode_t mode
, RefCount
<IORequestor
> callback
)
75 /* Simulate async calls */
76 fd
= file_open(path_
, flags
);
77 ioRequestor
= callback
;
80 debugs(79,3, HERE
<< "open error: " << xstrerror());
84 debugs(79,3, HERE
<< "FD " << fd
);
86 // setup mapping boundaries
88 if (fstat(fd
, &sb
) == 0)
89 maxOffset
= sb
.st_size
; // we do not expect it to change
92 callback
->ioCompletedNotification();
96 * Alias for MmappedFile::open(...)
97 \copydoc MmappedFile::open(int flags, mode_t mode, RefCount<IORequestor> callback)
100 MmappedFile::create(int flags
, mode_t mode
, RefCount
<IORequestor
> callback
)
102 /* We use the same logic path for open */
103 open(flags
, mode
, callback
);
106 void MmappedFile::doClose()
111 store_open_disk_fd
--;
118 debugs(79, 3, HERE
<< this << " closing for " << ioRequestor
);
120 assert(ioRequestor
!= NULL
);
121 ioRequestor
->closeCompleted();
125 MmappedFile::canRead() const
131 MmappedFile::canWrite() const
137 MmappedFile::error() const
143 MmappedFile::read(ReadRequest
*aRequest
)
145 debugs(79,3, HERE
<< "(FD " << fd
<< ", " << aRequest
->len
<< ", " <<
146 aRequest
->offset
<< ")");
149 assert(ioRequestor
!= NULL
);
150 assert(aRequest
->len
> 0); // TODO: work around mmap failures on zero-len?
151 assert(aRequest
->offset
>= 0);
152 assert(!error_
); // TODO: propagate instead?
154 assert(minOffset
< 0 || minOffset
<= aRequest
->offset
);
155 assert(maxOffset
< 0 || static_cast<uint64_t>(aRequest
->offset
+ aRequest
->len
) <= static_cast<uint64_t>(maxOffset
));
157 Mmapping
mapping(fd
, aRequest
->len
, PROT_READ
, MAP_PRIVATE
| MAP_NORESERVE
,
161 if (void *buf
= mapping
.map()) {
162 memcpy(aRequest
->buf
, buf
, aRequest
->len
);
163 done
= mapping
.unmap();
167 const ssize_t rlen
= error_
? -1 : (ssize_t
)aRequest
->len
;
168 const int errflag
= error_
? DISK_ERROR
:DISK_OK
;
169 ioRequestor
->readCompleted(aRequest
->buf
, rlen
, errflag
, aRequest
);
173 MmappedFile::write(WriteRequest
*aRequest
)
175 debugs(79,3, HERE
<< "(FD " << fd
<< ", " << aRequest
->len
<< ", " <<
176 aRequest
->offset
<< ")");
179 assert(ioRequestor
!= NULL
);
180 assert(aRequest
->len
> 0); // TODO: work around mmap failures on zero-len?
181 assert(aRequest
->offset
>= 0);
182 assert(!error_
); // TODO: propagate instead?
184 assert(minOffset
< 0 || minOffset
<= aRequest
->offset
);
185 assert(maxOffset
< 0 || static_cast<uint64_t>(aRequest
->offset
+ aRequest
->len
) <= static_cast<uint64_t>(maxOffset
));
187 const ssize_t written
=
188 pwrite(fd
, aRequest
->buf
, aRequest
->len
, aRequest
->offset
);
190 debugs(79,1, HERE
<< "error: " << xstrerr(errno
));
192 } else if (static_cast<size_t>(written
) != aRequest
->len
) {
193 debugs(79,1, HERE
<< "problem: " << written
<< " < " << aRequest
->len
);
197 if (aRequest
->free_func
)
198 (aRequest
->free_func
)(const_cast<char*>(aRequest
->buf
)); // broken API?
201 debugs(79,5, HERE
<< "wrote " << aRequest
->len
<< " to FD " << fd
<< " at " << aRequest
->offset
);
206 const ssize_t rlen
= error_
? 0 : (ssize_t
)aRequest
->len
;
207 const int errflag
= error_
? DISK_ERROR
:DISK_OK
;
208 ioRequestor
->writeCompleted(errflag
, rlen
, aRequest
);
211 /// we only support blocking I/O
213 MmappedFile::ioInProgress() const
218 Mmapping::Mmapping(int aFd
, size_t aLength
, int aProt
, int aFlags
, off_t anOffset
):
219 fd(aFd
), length(aLength
), prot(aProt
), flags(aFlags
), offset(anOffset
),
224 Mmapping::~Mmapping()
233 // mmap(2) requires that offset is a multiple of the page size
234 static const int pageSize
= getpagesize();
235 delta
= offset
% pageSize
;
237 buf
= mmap(NULL
, length
+ delta
, prot
, flags
, fd
, offset
- delta
);
239 if (buf
== MAP_FAILED
) {
240 const int errNo
= errno
;
241 debugs(79,3, HERE
<< "error FD " << fd
<< "mmap(" << length
<< '+' <<
242 delta
<< ", " << offset
<< '-' << delta
<< "): " << xstrerr(errNo
));
247 return static_cast<char*>(buf
) + delta
;
253 debugs(79,9, HERE
<< "FD " << fd
<<
254 " munmap(" << buf
<< ", " << length
<< '+' << delta
<< ')');
256 if (!buf
) // forgot or failed to map
259 const bool error
= munmap(buf
, length
+ delta
) != 0;
261 const int errNo
= errno
;
262 debugs(79,3, HERE
<< "error FD " << fd
<<
263 " munmap(" << buf
<< ", " << length
<< '+' << delta
<< "): " <<
264 "): " << xstrerr(errNo
));
270 // TODO: check MAP_NORESERVE, consider MAP_POPULATE and MAP_FIXED