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f5eef98c | 1 | /* |
bde978a6 | 2 | * Copyright (C) 1996-2015 The Squid Software Foundation and contributors |
f5eef98c | 3 | * |
bbc27441 AJ |
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. | |
f5eef98c DK |
7 | */ |
8 | ||
bbc27441 AJ |
9 | /* DEBUG: section 54 Interprocess Communication */ |
10 | ||
f7f3304a | 11 | #include "squid.h" |
e08b0f77 | 12 | #include "base/TextException.h" |
c975f532 | 13 | #include "compat/shm.h" |
af69c635 FC |
14 | #include "Debug.h" |
15 | #include "fatal.h" | |
d8a82533 | 16 | #include "ipc/mem/Segment.h" |
1860fbac | 17 | #include "SBuf.h" |
5bed43d6 | 18 | #include "tools.h" |
f5eef98c | 19 | |
7e851a39 | 20 | #if HAVE_FCNTL_H |
f5eef98c | 21 | #include <fcntl.h> |
7e851a39 AJ |
22 | #endif |
23 | #if HAVE_SYS_MMAN_H | |
f5eef98c | 24 | #include <sys/mman.h> |
7e851a39 AJ |
25 | #endif |
26 | #if HAVE_SYS_STAT_H | |
f5eef98c | 27 | #include <sys/stat.h> |
7e851a39 AJ |
28 | #endif |
29 | #if HAVE_UNISTD_H | |
f5eef98c | 30 | #include <unistd.h> |
7e851a39 | 31 | #endif |
f5eef98c | 32 | |
ef8de464 AR |
33 | // test cases change this |
34 | const char *Ipc::Mem::Segment::BasePath = DEFAULT_STATEDIR; | |
35 | ||
be9cb908 DK |
36 | void * |
37 | Ipc::Mem::Segment::reserve(size_t chunkSize) | |
38 | { | |
39 | Must(theMem); | |
40 | // check for overflows | |
41 | // chunkSize >= 0 may result in warnings on systems where off_t is unsigned | |
42 | assert(!chunkSize || static_cast<off_t>(chunkSize) > 0); | |
43 | assert(static_cast<off_t>(chunkSize) <= theSize); | |
44 | assert(theReserved <= theSize - static_cast<off_t>(chunkSize)); | |
45 | void *result = reinterpret_cast<char*>(theMem) + theReserved; | |
46 | theReserved += chunkSize; | |
47 | return result; | |
48 | } | |
49 | ||
1860fbac AR |
50 | SBuf |
51 | Ipc::Mem::Segment::Name(const SBuf &prefix, const char *suffix) | |
52 | { | |
53 | SBuf result = prefix; | |
54 | result.append("_"); | |
55 | result.append(suffix); | |
56 | return result; | |
57 | } | |
58 | ||
be9cb908 DK |
59 | #if HAVE_SHM |
60 | ||
d8a82533 | 61 | Ipc::Mem::Segment::Segment(const char *const id): |
f53969cc SM |
62 | theFD(-1), theName(GenerateName(id)), theMem(NULL), |
63 | theSize(0), theReserved(0), doUnlink(false) | |
f5eef98c DK |
64 | { |
65 | } | |
66 | ||
9199139f AR |
67 | Ipc::Mem::Segment::~Segment() |
68 | { | |
f5eef98c DK |
69 | if (theFD >= 0) { |
70 | detach(); | |
d8a82533 | 71 | if (close(theFD) != 0) |
be1d3736 | 72 | debugs(54, 5, HERE << "close " << theName << ": " << xstrerror()); |
f5eef98c | 73 | } |
68353d5a DK |
74 | if (doUnlink) |
75 | unlink(); | |
f5eef98c DK |
76 | } |
77 | ||
be9cb908 | 78 | // fake Ipc::Mem::Segment::Enabled (!HAVE_SHM) is more selective |
c975f532 | 79 | bool |
9199139f AR |
80 | Ipc::Mem::Segment::Enabled() |
81 | { | |
c975f532 | 82 | return true; |
c975f532 DK |
83 | } |
84 | ||
f5eef98c | 85 | void |
e08b0f77 | 86 | Ipc::Mem::Segment::create(const off_t aSize) |
f5eef98c DK |
87 | { |
88 | assert(aSize > 0); | |
89 | assert(theFD < 0); | |
90 | ||
e1825c5d | 91 | theFD = shm_open(theName.termedBuf(), O_CREAT | O_RDWR | O_TRUNC, |
f5eef98c DK |
92 | S_IRUSR | S_IWUSR); |
93 | if (theFD < 0) { | |
be1d3736 | 94 | debugs(54, 5, HERE << "shm_open " << theName << ": " << xstrerror()); |
77915f06 AR |
95 | fatalf("Ipc::Mem::Segment::create failed to shm_open(%s): %s\n", |
96 | theName.termedBuf(), xstrerror()); | |
f5eef98c DK |
97 | } |
98 | ||
99 | if (ftruncate(theFD, aSize)) { | |
be1d3736 | 100 | debugs(54, 5, HERE << "ftruncate " << theName << ": " << xstrerror()); |
b46ae525 AR |
101 | fatalf("Ipc::Mem::Segment::create failed to ftruncate(%s): %s\n", |
102 | theName.termedBuf(), xstrerror()); | |
f5eef98c DK |
103 | } |
104 | ||
e08b0f77 AR |
105 | assert(statSize("Ipc::Mem::Segment::create") == aSize); // paranoid |
106 | ||
f5eef98c | 107 | theSize = aSize; |
937d0d3f | 108 | theReserved = 0; |
68353d5a | 109 | doUnlink = true; |
f5eef98c | 110 | |
446485d5 AR |
111 | debugs(54, 3, HERE << "created " << theName << " segment: " << theSize); |
112 | ||
f5eef98c DK |
113 | attach(); |
114 | } | |
115 | ||
116 | void | |
d8a82533 | 117 | Ipc::Mem::Segment::open() |
f5eef98c DK |
118 | { |
119 | assert(theFD < 0); | |
120 | ||
121 | theFD = shm_open(theName.termedBuf(), O_RDWR, 0); | |
122 | if (theFD < 0) { | |
be1d3736 | 123 | debugs(54, 5, HERE << "shm_open " << theName << ": " << xstrerror()); |
77915f06 AR |
124 | fatalf("Ipc::Mem::Segment::open failed to shm_open(%s): %s\n", |
125 | theName.termedBuf(), xstrerror()); | |
f5eef98c DK |
126 | } |
127 | ||
e08b0f77 | 128 | theSize = statSize("Ipc::Mem::Segment::open"); |
f5eef98c | 129 | |
446485d5 AR |
130 | debugs(54, 3, HERE << "opened " << theName << " segment: " << theSize); |
131 | ||
f5eef98c DK |
132 | attach(); |
133 | } | |
134 | ||
135 | /// Map the shared memory segment to the process memory space. | |
136 | void | |
d8a82533 | 137 | Ipc::Mem::Segment::attach() |
f5eef98c DK |
138 | { |
139 | assert(theFD >= 0); | |
f5eef98c DK |
140 | assert(!theMem); |
141 | ||
3a2ede14 AR |
142 | // mmap() accepts size_t for the size; we give it off_t which might |
143 | // be bigger; assert overflows until we support multiple mmap()s? | |
144 | assert(theSize == static_cast<off_t>(static_cast<size_t>(theSize))); | |
145 | ||
f5eef98c DK |
146 | void *const p = |
147 | mmap(NULL, theSize, PROT_READ | PROT_WRITE, MAP_SHARED, theFD, 0); | |
148 | if (p == MAP_FAILED) { | |
be1d3736 | 149 | debugs(54, 5, HERE << "mmap " << theName << ": " << xstrerror()); |
b46ae525 AR |
150 | fatalf("Ipc::Mem::Segment::attach failed to mmap(%s): %s\n", |
151 | theName.termedBuf(), xstrerror()); | |
f5eef98c DK |
152 | } |
153 | theMem = p; | |
154 | } | |
155 | ||
156 | /// Unmap the shared memory segment from the process memory space. | |
157 | void | |
d8a82533 | 158 | Ipc::Mem::Segment::detach() |
f5eef98c DK |
159 | { |
160 | if (!theMem) | |
161 | return; | |
162 | ||
163 | if (munmap(theMem, theSize)) { | |
be1d3736 | 164 | debugs(54, 5, HERE << "munmap " << theName << ": " << xstrerror()); |
b46ae525 AR |
165 | fatalf("Ipc::Mem::Segment::detach failed to munmap(%s): %s\n", |
166 | theName.termedBuf(), xstrerror()); | |
f5eef98c DK |
167 | } |
168 | theMem = 0; | |
169 | } | |
170 | ||
68353d5a DK |
171 | void |
172 | Ipc::Mem::Segment::unlink() | |
173 | { | |
174 | if (shm_unlink(theName.termedBuf()) != 0) | |
175 | debugs(54, 5, HERE << "shm_unlink(" << theName << "): " << xstrerror()); | |
176 | else | |
177 | debugs(54, 3, HERE << "unlinked " << theName << " segment"); | |
178 | } | |
179 | ||
e08b0f77 AR |
180 | /// determines the size of the underlying "file" |
181 | off_t | |
182 | Ipc::Mem::Segment::statSize(const char *context) const | |
183 | { | |
184 | Must(theFD >= 0); | |
185 | ||
186 | struct stat s; | |
187 | memset(&s, 0, sizeof(s)); | |
188 | ||
189 | if (fstat(theFD, &s) != 0) { | |
b46ae525 AR |
190 | debugs(54, 5, HERE << context << " fstat " << theName << ": " << xstrerror()); |
191 | fatalf("Ipc::Mem::Segment::statSize: %s failed to fstat(%s): %s\n", | |
192 | context, theName.termedBuf(), xstrerror()); | |
e08b0f77 AR |
193 | } |
194 | ||
195 | return s.st_size; | |
196 | } | |
197 | ||
ef8de464 AR |
198 | /// Generate name for shared memory segment. Starts with a prefix required |
199 | /// for cross-platform portability and replaces all slashes in ID with dots. | |
f5eef98c | 200 | String |
d8a82533 | 201 | Ipc::Mem::Segment::GenerateName(const char *id) |
f5eef98c | 202 | { |
38189e84 | 203 | assert(BasePath && *BasePath); |
ef8de464 | 204 | static const bool nameIsPath = shm_portable_segment_name_is_path(); |
38189e84 AJ |
205 | String name; |
206 | if (nameIsPath) { | |
207 | name.append(BasePath); | |
208 | if (name[name.size()-1] != '/') | |
209 | name.append('/'); | |
210 | } else | |
211 | name.append("/squid-"); | |
ef8de464 AR |
212 | |
213 | // append id, replacing slashes with dots | |
9a51593d DK |
214 | for (const char *slash = strchr(id, '/'); slash; slash = strchr(id, '/')) { |
215 | if (id != slash) { | |
216 | name.append(id, slash - id); | |
217 | name.append('.'); | |
218 | } | |
219 | id = slash + 1; | |
220 | } | |
f5eef98c | 221 | name.append(id); |
ef8de464 AR |
222 | |
223 | name.append(".shm"); // to distinguish from non-segments when nameIsPath | |
f5eef98c DK |
224 | return name; |
225 | } | |
be9cb908 DK |
226 | |
227 | #else // HAVE_SHM | |
228 | ||
229 | #include <map> | |
230 | ||
231 | typedef std::map<String, Ipc::Mem::Segment *> SegmentMap; | |
232 | static SegmentMap Segments; | |
233 | ||
234 | Ipc::Mem::Segment::Segment(const char *const id): | |
f53969cc | 235 | theName(id), theMem(NULL), theSize(0), theReserved(0), doUnlink(false) |
be9cb908 DK |
236 | { |
237 | } | |
238 | ||
239 | Ipc::Mem::Segment::~Segment() | |
240 | { | |
241 | if (doUnlink) { | |
242 | delete [] static_cast<char *>(theMem); | |
44c64af0 AR |
243 | theMem = NULL; |
244 | Segments.erase(theName); | |
245 | debugs(54, 3, HERE << "unlinked " << theName << " fake segment"); | |
be9cb908 DK |
246 | } |
247 | } | |
248 | ||
249 | bool | |
250 | Ipc::Mem::Segment::Enabled() | |
251 | { | |
38a129ef | 252 | return !UsingSmp() && IamWorkerProcess(); |
be9cb908 DK |
253 | } |
254 | ||
255 | void | |
256 | Ipc::Mem::Segment::create(const off_t aSize) | |
257 | { | |
258 | assert(aSize > 0); | |
259 | assert(!theMem); | |
260 | checkSupport("Fake segment creation"); | |
261 | ||
262 | const bool inserted = Segments.insert(std::make_pair(theName, this)).second; | |
263 | if (!inserted) | |
264 | fatalf("Duplicate fake segment creation: %s", theName.termedBuf()); | |
265 | ||
266 | theMem = new char[aSize]; | |
267 | theSize = aSize; | |
268 | doUnlink = true; | |
269 | ||
270 | debugs(54, 3, HERE << "created " << theName << " fake segment: " << theSize); | |
271 | } | |
272 | ||
273 | void | |
274 | Ipc::Mem::Segment::open() | |
275 | { | |
276 | assert(!theMem); | |
277 | checkSupport("Fake segment open"); | |
278 | ||
279 | const SegmentMap::const_iterator i = Segments.find(theName); | |
280 | if (i == Segments.end()) | |
281 | fatalf("Fake segment not found: %s", theName.termedBuf()); | |
282 | ||
283 | const Segment &segment = *i->second; | |
284 | theMem = segment.theMem; | |
285 | theSize = segment.theSize; | |
286 | ||
287 | debugs(54, 3, HERE << "opened " << theName << " fake segment: " << theSize); | |
288 | } | |
289 | ||
290 | void | |
291 | Ipc::Mem::Segment::checkSupport(const char *const context) | |
292 | { | |
293 | if (!Enabled()) { | |
b46ae525 AR |
294 | debugs(54, 5, HERE << context << |
295 | ": True shared memory segments are not supported. " | |
be9cb908 | 296 | "Cannot fake shared segments in SMP config."); |
b46ae525 AR |
297 | fatalf("Ipc::Mem::Segment: Cannot fake shared segments in SMP config (%s)\n", |
298 | context); | |
be9cb908 DK |
299 | } |
300 | } | |
301 | ||
302 | #endif // HAVE_SHM | |
f5480a9e DK |
303 | |
304 | void | |
21b7990f | 305 | Ipc::Mem::RegisteredRunner::useConfig() |
f5480a9e DK |
306 | { |
307 | // If Squid is built with real segments, we create() real segments | |
308 | // in the master process only. Otherwise, we create() fake | |
309 | // segments in each worker process. We assume that only workers | |
310 | // need and can work with fake segments. | |
311 | #if HAVE_SHM | |
312 | if (IamMasterProcess()) | |
313 | #else | |
9e3f96a4 | 314 | if (IamWorkerProcess()) |
f5480a9e | 315 | #endif |
21b7990f | 316 | create(); |
f5480a9e DK |
317 | |
318 | // we assume that master process does not need shared segments | |
319 | // unless it is also a worker | |
320 | if (!InDaemonMode() || !IamMasterProcess()) | |
21b7990f | 321 | open(); |
f5480a9e | 322 | } |
f53969cc | 323 |