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16e9f408 LP |
1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2012 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
16e9f408 LP |
22 | #include <errno.h> |
23 | #include <stdlib.h> | |
f8019684 | 24 | #include <sys/mman.h> |
16e9f408 | 25 | |
b5efdb8a | 26 | #include "alloc-util.h" |
f8019684 LP |
27 | #include "hashmap.h" |
28 | #include "list.h" | |
29 | #include "log.h" | |
f8019684 | 30 | #include "macro.h" |
16e9f408 | 31 | #include "mmap-cache.h" |
cf0fbc49 TA |
32 | #include "sigbus.h" |
33 | #include "util.h" | |
16e9f408 | 34 | |
f8019684 LP |
35 | typedef struct Window Window; |
36 | typedef struct Context Context; | |
37 | typedef struct FileDescriptor FileDescriptor; | |
84168d80 | 38 | |
f8019684 LP |
39 | struct Window { |
40 | MMapCache *cache; | |
41 | ||
fa6ac760 | 42 | bool invalidated; |
1b8951e5 | 43 | bool keep_always; |
f8019684 | 44 | bool in_unused; |
16e9f408 | 45 | |
68667801 | 46 | int prot; |
16e9f408 LP |
47 | void *ptr; |
48 | uint64_t offset; | |
f8019684 LP |
49 | size_t size; |
50 | ||
51 | FileDescriptor *fd; | |
16e9f408 | 52 | |
f8019684 LP |
53 | LIST_FIELDS(Window, by_fd); |
54 | LIST_FIELDS(Window, unused); | |
55 | ||
56 | LIST_HEAD(Context, contexts); | |
57 | }; | |
16e9f408 | 58 | |
f8019684 LP |
59 | struct Context { |
60 | MMapCache *cache; | |
61 | unsigned id; | |
62 | Window *window; | |
16e9f408 | 63 | |
f8019684 LP |
64 | LIST_FIELDS(Context, by_window); |
65 | }; | |
66 | ||
67 | struct FileDescriptor { | |
68 | MMapCache *cache; | |
16e9f408 | 69 | int fd; |
fa6ac760 | 70 | bool sigbus; |
f8019684 LP |
71 | LIST_HEAD(Window, windows); |
72 | }; | |
16e9f408 LP |
73 | |
74 | struct MMapCache { | |
f8019684 | 75 | int n_ref; |
68667801 | 76 | unsigned n_windows; |
16e9f408 | 77 | |
bf807d4d LP |
78 | unsigned n_hit, n_missed; |
79 | ||
80 | ||
f8019684 | 81 | Hashmap *fds; |
69adae51 | 82 | Context *contexts[MMAP_CACHE_MAX_CONTEXTS]; |
16e9f408 | 83 | |
f8019684 LP |
84 | LIST_HEAD(Window, unused); |
85 | Window *last_unused; | |
16e9f408 LP |
86 | }; |
87 | ||
f8019684 | 88 | #define WINDOWS_MIN 64 |
fad5a6c6 MS |
89 | |
90 | #ifdef ENABLE_DEBUG_MMAP_CACHE | |
91 | /* Tiny windows increase mmap activity and the chance of exposing unsafe use. */ | |
92 | # define WINDOW_SIZE (page_size()) | |
93 | #else | |
94 | # define WINDOW_SIZE (8ULL*1024ULL*1024ULL) | |
95 | #endif | |
16e9f408 | 96 | |
f8019684 LP |
97 | MMapCache* mmap_cache_new(void) { |
98 | MMapCache *m; | |
16e9f408 | 99 | |
f8019684 LP |
100 | m = new0(MMapCache, 1); |
101 | if (!m) | |
102 | return NULL; | |
16e9f408 | 103 | |
f8019684 LP |
104 | m->n_ref = 1; |
105 | return m; | |
16e9f408 LP |
106 | } |
107 | ||
f8019684 | 108 | MMapCache* mmap_cache_ref(MMapCache *m) { |
16e9f408 | 109 | assert(m); |
f8019684 | 110 | assert(m->n_ref > 0); |
16e9f408 | 111 | |
f8019684 LP |
112 | m->n_ref ++; |
113 | return m; | |
114 | } | |
f65425cb | 115 | |
f8019684 LP |
116 | static void window_unlink(Window *w) { |
117 | Context *c; | |
f65425cb | 118 | |
f8019684 | 119 | assert(w); |
16e9f408 | 120 | |
f8019684 LP |
121 | if (w->ptr) |
122 | munmap(w->ptr, w->size); | |
16e9f408 | 123 | |
f8019684 | 124 | if (w->fd) |
71fda00f | 125 | LIST_REMOVE(by_fd, w->fd->windows, w); |
16e9f408 | 126 | |
f8019684 LP |
127 | if (w->in_unused) { |
128 | if (w->cache->last_unused == w) | |
129 | w->cache->last_unused = w->unused_prev; | |
16e9f408 | 130 | |
71fda00f | 131 | LIST_REMOVE(unused, w->cache->unused, w); |
f65425cb | 132 | } |
16e9f408 | 133 | |
f8019684 LP |
134 | LIST_FOREACH(by_window, c, w->contexts) { |
135 | assert(c->window == w); | |
136 | c->window = NULL; | |
f65425cb | 137 | } |
16e9f408 LP |
138 | } |
139 | ||
fa6ac760 LP |
140 | static void window_invalidate(Window *w) { |
141 | assert(w); | |
142 | ||
143 | if (w->invalidated) | |
144 | return; | |
145 | ||
146 | /* Replace the window with anonymous pages. This is useful | |
147 | * when we hit a SIGBUS and want to make sure the file cannot | |
148 | * trigger any further SIGBUS, possibly overrunning the sigbus | |
149 | * queue. */ | |
150 | ||
151 | assert_se(mmap(w->ptr, w->size, w->prot, MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, -1, 0) == w->ptr); | |
152 | w->invalidated = true; | |
153 | } | |
154 | ||
f8019684 LP |
155 | static void window_free(Window *w) { |
156 | assert(w); | |
f65425cb | 157 | |
f8019684 | 158 | window_unlink(w); |
89de6947 | 159 | w->cache->n_windows--; |
f8019684 LP |
160 | free(w); |
161 | } | |
f65425cb | 162 | |
44a6b1b6 | 163 | _pure_ static bool window_matches(Window *w, int fd, int prot, uint64_t offset, size_t size) { |
f8019684 LP |
164 | assert(w); |
165 | assert(fd >= 0); | |
166 | assert(size > 0); | |
16e9f408 | 167 | |
f8019684 LP |
168 | return |
169 | w->fd && | |
170 | fd == w->fd->fd && | |
171 | prot == w->prot && | |
172 | offset >= w->offset && | |
173 | offset + size <= w->offset + w->size; | |
16e9f408 LP |
174 | } |
175 | ||
f8019684 LP |
176 | static Window *window_add(MMapCache *m) { |
177 | Window *w; | |
16e9f408 LP |
178 | |
179 | assert(m); | |
16e9f408 | 180 | |
f8019684 | 181 | if (!m->last_unused || m->n_windows <= WINDOWS_MIN) { |
f65425cb | 182 | |
f8019684 LP |
183 | /* Allocate a new window */ |
184 | w = new0(Window, 1); | |
185 | if (!w) | |
186 | return NULL; | |
89de6947 | 187 | m->n_windows++; |
f65425cb | 188 | } else { |
16e9f408 | 189 | |
f8019684 LP |
190 | /* Reuse an existing one */ |
191 | w = m->last_unused; | |
192 | window_unlink(w); | |
193 | zero(*w); | |
f65425cb | 194 | } |
f8019684 LP |
195 | |
196 | w->cache = m; | |
197 | return w; | |
16e9f408 LP |
198 | } |
199 | ||
f8019684 LP |
200 | static void context_detach_window(Context *c) { |
201 | Window *w; | |
16e9f408 | 202 | |
f8019684 | 203 | assert(c); |
16e9f408 | 204 | |
f8019684 | 205 | if (!c->window) |
16e9f408 LP |
206 | return; |
207 | ||
f8019684 LP |
208 | w = c->window; |
209 | c->window = NULL; | |
71fda00f | 210 | LIST_REMOVE(by_window, w->contexts, c); |
16e9f408 | 211 | |
1b8951e5 | 212 | if (!w->contexts && !w->keep_always) { |
f8019684 | 213 | /* Not used anymore? */ |
fad5a6c6 MS |
214 | #ifdef ENABLE_DEBUG_MMAP_CACHE |
215 | /* Unmap unused windows immediately to expose use-after-unmap | |
216 | * by SIGSEGV. */ | |
217 | window_free(w); | |
218 | #else | |
71fda00f | 219 | LIST_PREPEND(unused, c->cache->unused, w); |
f8019684 LP |
220 | if (!c->cache->last_unused) |
221 | c->cache->last_unused = w; | |
16e9f408 | 222 | |
f8019684 | 223 | w->in_unused = true; |
fad5a6c6 | 224 | #endif |
f8019684 | 225 | } |
16e9f408 LP |
226 | } |
227 | ||
f8019684 LP |
228 | static void context_attach_window(Context *c, Window *w) { |
229 | assert(c); | |
230 | assert(w); | |
16e9f408 | 231 | |
f8019684 | 232 | if (c->window == w) |
16e9f408 LP |
233 | return; |
234 | ||
f8019684 | 235 | context_detach_window(c); |
16e9f408 | 236 | |
e18021f7 | 237 | if (w->in_unused) { |
f8019684 | 238 | /* Used again? */ |
71fda00f | 239 | LIST_REMOVE(unused, c->cache->unused, w); |
a2ab7ee6 CG |
240 | if (c->cache->last_unused == w) |
241 | c->cache->last_unused = w->unused_prev; | |
16e9f408 | 242 | |
f8019684 LP |
243 | w->in_unused = false; |
244 | } | |
f65425cb | 245 | |
f8019684 | 246 | c->window = w; |
71fda00f | 247 | LIST_PREPEND(by_window, w->contexts, c); |
16e9f408 LP |
248 | } |
249 | ||
f8019684 LP |
250 | static Context *context_add(MMapCache *m, unsigned id) { |
251 | Context *c; | |
16e9f408 LP |
252 | |
253 | assert(m); | |
254 | ||
69adae51 | 255 | c = m->contexts[id]; |
f8019684 LP |
256 | if (c) |
257 | return c; | |
258 | ||
f8019684 LP |
259 | c = new0(Context, 1); |
260 | if (!c) | |
261 | return NULL; | |
16e9f408 | 262 | |
f8019684 LP |
263 | c->cache = m; |
264 | c->id = id; | |
16e9f408 | 265 | |
69adae51 MS |
266 | assert(!m->contexts[id]); |
267 | m->contexts[id] = c; | |
16e9f408 | 268 | |
f8019684 | 269 | return c; |
16e9f408 LP |
270 | } |
271 | ||
f8019684 LP |
272 | static void context_free(Context *c) { |
273 | assert(c); | |
16e9f408 | 274 | |
f8019684 | 275 | context_detach_window(c); |
16e9f408 | 276 | |
69adae51 MS |
277 | if (c->cache) { |
278 | assert(c->cache->contexts[c->id] == c); | |
279 | c->cache->contexts[c->id] = NULL; | |
280 | } | |
16e9f408 | 281 | |
f8019684 LP |
282 | free(c); |
283 | } | |
284 | ||
285 | static void fd_free(FileDescriptor *f) { | |
286 | assert(f); | |
287 | ||
288 | while (f->windows) | |
289 | window_free(f->windows); | |
290 | ||
291 | if (f->cache) | |
292 | assert_se(hashmap_remove(f->cache->fds, INT_TO_PTR(f->fd + 1))); | |
293 | ||
294 | free(f); | |
295 | } | |
296 | ||
297 | static FileDescriptor* fd_add(MMapCache *m, int fd) { | |
298 | FileDescriptor *f; | |
299 | int r; | |
300 | ||
301 | assert(m); | |
302 | assert(fd >= 0); | |
303 | ||
304 | f = hashmap_get(m->fds, INT_TO_PTR(fd + 1)); | |
305 | if (f) | |
306 | return f; | |
307 | ||
d5099efc | 308 | r = hashmap_ensure_allocated(&m->fds, NULL); |
f8019684 | 309 | if (r < 0) |
16e9f408 | 310 | return NULL; |
16e9f408 | 311 | |
f8019684 LP |
312 | f = new0(FileDescriptor, 1); |
313 | if (!f) | |
16e9f408 | 314 | return NULL; |
16e9f408 | 315 | |
f8019684 LP |
316 | f->cache = m; |
317 | f->fd = fd; | |
318 | ||
319 | r = hashmap_put(m->fds, UINT_TO_PTR(fd + 1), f); | |
320 | if (r < 0) { | |
321 | free(f); | |
16e9f408 LP |
322 | return NULL; |
323 | } | |
324 | ||
f8019684 | 325 | return f; |
16e9f408 LP |
326 | } |
327 | ||
f8019684 | 328 | static void mmap_cache_free(MMapCache *m) { |
f8019684 | 329 | FileDescriptor *f; |
69adae51 | 330 | int i; |
f8019684 | 331 | |
16e9f408 | 332 | assert(m); |
16e9f408 | 333 | |
69adae51 MS |
334 | for (i = 0; i < MMAP_CACHE_MAX_CONTEXTS; i++) |
335 | if (m->contexts[i]) | |
336 | context_free(m->contexts[i]); | |
8e6d9397 | 337 | |
f8019684 LP |
338 | while ((f = hashmap_first(m->fds))) |
339 | fd_free(f); | |
340 | ||
8e6d9397 GM |
341 | hashmap_free(m->fds); |
342 | ||
f8019684 LP |
343 | while (m->unused) |
344 | window_free(m->unused); | |
345 | ||
346 | free(m); | |
16e9f408 LP |
347 | } |
348 | ||
349 | MMapCache* mmap_cache_unref(MMapCache *m) { | |
350 | assert(m); | |
351 | assert(m->n_ref > 0); | |
352 | ||
f8019684 LP |
353 | m->n_ref --; |
354 | if (m->n_ref == 0) | |
16e9f408 | 355 | mmap_cache_free(m); |
16e9f408 LP |
356 | |
357 | return NULL; | |
358 | } | |
359 | ||
f8019684 LP |
360 | static int make_room(MMapCache *m) { |
361 | assert(m); | |
362 | ||
363 | if (!m->last_unused) | |
364 | return 0; | |
365 | ||
366 | window_free(m->last_unused); | |
367 | return 1; | |
368 | } | |
369 | ||
370 | static int try_context( | |
371 | MMapCache *m, | |
372 | int fd, | |
373 | int prot, | |
374 | unsigned context, | |
375 | bool keep_always, | |
376 | uint64_t offset, | |
377 | size_t size, | |
1b8951e5 | 378 | void **ret) { |
f8019684 LP |
379 | |
380 | Context *c; | |
f65425cb | 381 | |
16e9f408 | 382 | assert(m); |
f8019684 LP |
383 | assert(m->n_ref > 0); |
384 | assert(fd >= 0); | |
385 | assert(size > 0); | |
1b8951e5 | 386 | assert(ret); |
16e9f408 | 387 | |
69adae51 | 388 | c = m->contexts[context]; |
f8019684 | 389 | if (!c) |
16e9f408 | 390 | return 0; |
16e9f408 | 391 | |
f8019684 | 392 | assert(c->id == context); |
16e9f408 | 393 | |
f8019684 LP |
394 | if (!c->window) |
395 | return 0; | |
f65425cb | 396 | |
f8019684 | 397 | if (!window_matches(c->window, fd, prot, offset, size)) { |
f65425cb | 398 | |
f8019684 LP |
399 | /* Drop the reference to the window, since it's unnecessary now */ |
400 | context_detach_window(c); | |
401 | return 0; | |
f65425cb LP |
402 | } |
403 | ||
fa6ac760 LP |
404 | if (c->window->fd->sigbus) |
405 | return -EIO; | |
406 | ||
1b8951e5 | 407 | c->window->keep_always |= keep_always; |
16e9f408 | 408 | |
1b8951e5 | 409 | *ret = (uint8_t*) c->window->ptr + (offset - c->window->offset); |
f8019684 | 410 | return 1; |
16e9f408 LP |
411 | } |
412 | ||
f8019684 LP |
413 | static int find_mmap( |
414 | MMapCache *m, | |
415 | int fd, | |
416 | int prot, | |
417 | unsigned context, | |
418 | bool keep_always, | |
419 | uint64_t offset, | |
420 | size_t size, | |
1b8951e5 | 421 | void **ret) { |
f8019684 LP |
422 | |
423 | FileDescriptor *f; | |
424 | Window *w; | |
425 | Context *c; | |
16e9f408 LP |
426 | |
427 | assert(m); | |
f8019684 LP |
428 | assert(m->n_ref > 0); |
429 | assert(fd >= 0); | |
430 | assert(size > 0); | |
16e9f408 | 431 | |
f8019684 LP |
432 | f = hashmap_get(m->fds, INT_TO_PTR(fd + 1)); |
433 | if (!f) | |
434 | return 0; | |
16e9f408 | 435 | |
f8019684 | 436 | assert(f->fd == fd); |
16e9f408 | 437 | |
fa6ac760 LP |
438 | if (f->sigbus) |
439 | return -EIO; | |
440 | ||
f8019684 LP |
441 | LIST_FOREACH(by_fd, w, f->windows) |
442 | if (window_matches(w, fd, prot, offset, size)) | |
443 | break; | |
16e9f408 | 444 | |
f8019684 LP |
445 | if (!w) |
446 | return 0; | |
447 | ||
448 | c = context_add(m, context); | |
449 | if (!c) | |
450 | return -ENOMEM; | |
451 | ||
452 | context_attach_window(c, w); | |
ae97089d | 453 | w->keep_always += keep_always; |
16e9f408 | 454 | |
1b8951e5 | 455 | *ret = (uint8_t*) w->ptr + (offset - w->offset); |
f8019684 | 456 | return 1; |
16e9f408 LP |
457 | } |
458 | ||
f8019684 | 459 | static int add_mmap( |
16e9f408 LP |
460 | MMapCache *m, |
461 | int fd, | |
16e9f408 LP |
462 | int prot, |
463 | unsigned context, | |
fcde2389 | 464 | bool keep_always, |
16e9f408 | 465 | uint64_t offset, |
f8019684 | 466 | size_t size, |
fcde2389 | 467 | struct stat *st, |
1b8951e5 | 468 | void **ret) { |
16e9f408 | 469 | |
16e9f408 | 470 | uint64_t woffset, wsize; |
f8019684 LP |
471 | Context *c; |
472 | FileDescriptor *f; | |
473 | Window *w; | |
474 | void *d; | |
16e9f408 LP |
475 | int r; |
476 | ||
477 | assert(m); | |
f8019684 | 478 | assert(m->n_ref > 0); |
16e9f408 | 479 | assert(fd >= 0); |
16e9f408 | 480 | assert(size > 0); |
1b8951e5 | 481 | assert(ret); |
16e9f408 LP |
482 | |
483 | woffset = offset & ~((uint64_t) page_size() - 1ULL); | |
484 | wsize = size + (offset - woffset); | |
485 | wsize = PAGE_ALIGN(wsize); | |
486 | ||
487 | if (wsize < WINDOW_SIZE) { | |
488 | uint64_t delta; | |
489 | ||
beec0085 | 490 | delta = PAGE_ALIGN((WINDOW_SIZE - wsize) / 2); |
16e9f408 LP |
491 | |
492 | if (delta > offset) | |
493 | woffset = 0; | |
494 | else | |
495 | woffset -= delta; | |
496 | ||
497 | wsize = WINDOW_SIZE; | |
498 | } | |
499 | ||
fcde2389 LP |
500 | if (st) { |
501 | /* Memory maps that are larger then the files | |
c5315881 | 502 | underneath have undefined behavior. Hence, clamp |
fcde2389 LP |
503 | things to the file size if we know it */ |
504 | ||
505 | if (woffset >= (uint64_t) st->st_size) | |
506 | return -EADDRNOTAVAIL; | |
507 | ||
508 | if (woffset + wsize > (uint64_t) st->st_size) | |
509 | wsize = PAGE_ALIGN(st->st_size - woffset); | |
510 | } | |
511 | ||
16e9f408 LP |
512 | for (;;) { |
513 | d = mmap(NULL, wsize, prot, MAP_SHARED, fd, woffset); | |
514 | if (d != MAP_FAILED) | |
515 | break; | |
516 | if (errno != ENOMEM) | |
517 | return -errno; | |
518 | ||
f8019684 | 519 | r = make_room(m); |
16e9f408 LP |
520 | if (r < 0) |
521 | return r; | |
522 | if (r == 0) | |
523 | return -ENOMEM; | |
524 | } | |
525 | ||
f8019684 LP |
526 | c = context_add(m, context); |
527 | if (!c) | |
b67ddc7b | 528 | goto outofmem; |
16e9f408 | 529 | |
f8019684 LP |
530 | f = fd_add(m, fd); |
531 | if (!f) | |
b67ddc7b | 532 | goto outofmem; |
16e9f408 | 533 | |
f8019684 LP |
534 | w = window_add(m); |
535 | if (!w) | |
b67ddc7b | 536 | goto outofmem; |
16e9f408 | 537 | |
f8019684 LP |
538 | w->keep_always = keep_always; |
539 | w->ptr = d; | |
540 | w->offset = woffset; | |
541 | w->prot = prot; | |
542 | w->size = wsize; | |
543 | w->fd = f; | |
16e9f408 | 544 | |
71fda00f | 545 | LIST_PREPEND(by_fd, f->windows, w); |
16e9f408 | 546 | |
f8019684 LP |
547 | context_detach_window(c); |
548 | c->window = w; | |
71fda00f | 549 | LIST_PREPEND(by_window, w->contexts, c); |
16e9f408 | 550 | |
1b8951e5 | 551 | *ret = (uint8_t*) w->ptr + (offset - w->offset); |
16e9f408 | 552 | return 1; |
b67ddc7b PDS |
553 | |
554 | outofmem: | |
555 | munmap(d, wsize); | |
556 | return -ENOMEM; | |
16e9f408 LP |
557 | } |
558 | ||
559 | int mmap_cache_get( | |
560 | MMapCache *m, | |
561 | int fd, | |
562 | int prot, | |
563 | unsigned context, | |
fcde2389 | 564 | bool keep_always, |
16e9f408 | 565 | uint64_t offset, |
f8019684 | 566 | size_t size, |
fcde2389 | 567 | struct stat *st, |
1b8951e5 | 568 | void **ret) { |
16e9f408 | 569 | |
16e9f408 LP |
570 | int r; |
571 | ||
572 | assert(m); | |
f8019684 | 573 | assert(m->n_ref > 0); |
16e9f408 | 574 | assert(fd >= 0); |
16e9f408 | 575 | assert(size > 0); |
1b8951e5 | 576 | assert(ret); |
69adae51 | 577 | assert(context < MMAP_CACHE_MAX_CONTEXTS); |
16e9f408 | 578 | |
f8019684 | 579 | /* Check whether the current context is the right one already */ |
1b8951e5 | 580 | r = try_context(m, fd, prot, context, keep_always, offset, size, ret); |
bf807d4d LP |
581 | if (r != 0) { |
582 | m->n_hit ++; | |
16e9f408 | 583 | return r; |
bf807d4d | 584 | } |
16e9f408 | 585 | |
f8019684 | 586 | /* Search for a matching mmap */ |
1b8951e5 | 587 | r = find_mmap(m, fd, prot, context, keep_always, offset, size, ret); |
bf807d4d LP |
588 | if (r != 0) { |
589 | m->n_hit ++; | |
16e9f408 | 590 | return r; |
bf807d4d LP |
591 | } |
592 | ||
593 | m->n_missed++; | |
16e9f408 | 594 | |
f8019684 | 595 | /* Create a new mmap */ |
1b8951e5 | 596 | return add_mmap(m, fd, prot, context, keep_always, offset, size, st, ret); |
ae97089d ZJS |
597 | } |
598 | ||
fa6ac760 LP |
599 | unsigned mmap_cache_get_hit(MMapCache *m) { |
600 | assert(m); | |
601 | ||
602 | return m->n_hit; | |
603 | } | |
604 | ||
605 | unsigned mmap_cache_get_missed(MMapCache *m) { | |
606 | assert(m); | |
607 | ||
608 | return m->n_missed; | |
609 | } | |
610 | ||
611 | static void mmap_cache_process_sigbus(MMapCache *m) { | |
612 | bool found = false; | |
f8019684 | 613 | FileDescriptor *f; |
fa6ac760 LP |
614 | Iterator i; |
615 | int r; | |
16e9f408 LP |
616 | |
617 | assert(m); | |
16e9f408 | 618 | |
fa6ac760 LP |
619 | /* Iterate through all triggered pages and mark their files as |
620 | * invalidated */ | |
621 | for (;;) { | |
622 | bool ours; | |
623 | void *addr; | |
624 | ||
625 | r = sigbus_pop(&addr); | |
626 | if (_likely_(r == 0)) | |
627 | break; | |
628 | if (r < 0) { | |
629 | log_error_errno(r, "SIGBUS handling failed: %m"); | |
630 | abort(); | |
631 | } | |
632 | ||
633 | ours = false; | |
634 | HASHMAP_FOREACH(f, m->fds, i) { | |
635 | Window *w; | |
636 | ||
637 | LIST_FOREACH(by_fd, w, f->windows) { | |
638 | if ((uint8_t*) addr >= (uint8_t*) w->ptr && | |
639 | (uint8_t*) addr < (uint8_t*) w->ptr + w->size) { | |
640 | found = ours = f->sigbus = true; | |
641 | break; | |
642 | } | |
643 | } | |
644 | ||
645 | if (ours) | |
646 | break; | |
647 | } | |
648 | ||
649 | /* Didn't find a matching window, give up */ | |
650 | if (!ours) { | |
651 | log_error("Unknown SIGBUS page, aborting."); | |
652 | abort(); | |
653 | } | |
654 | } | |
655 | ||
656 | /* The list of triggered pages is now empty. Now, let's remap | |
657 | * all windows of the triggered file to anonymous maps, so | |
658 | * that no page of the file in question is triggered again, so | |
659 | * that we can be sure not to hit the queue size limit. */ | |
660 | if (_likely_(!found)) | |
16e9f408 | 661 | return; |
16e9f408 | 662 | |
fa6ac760 LP |
663 | HASHMAP_FOREACH(f, m->fds, i) { |
664 | Window *w; | |
665 | ||
666 | if (!f->sigbus) | |
667 | continue; | |
668 | ||
669 | LIST_FOREACH(by_fd, w, f->windows) | |
670 | window_invalidate(w); | |
671 | } | |
f8019684 | 672 | } |
16e9f408 | 673 | |
fa6ac760 LP |
674 | bool mmap_cache_got_sigbus(MMapCache *m, int fd) { |
675 | FileDescriptor *f; | |
676 | ||
bf807d4d | 677 | assert(m); |
fa6ac760 | 678 | assert(fd >= 0); |
bf807d4d | 679 | |
fa6ac760 LP |
680 | mmap_cache_process_sigbus(m); |
681 | ||
682 | f = hashmap_get(m->fds, INT_TO_PTR(fd + 1)); | |
683 | if (!f) | |
684 | return false; | |
685 | ||
686 | return f->sigbus; | |
bf807d4d LP |
687 | } |
688 | ||
fa6ac760 LP |
689 | void mmap_cache_close_fd(MMapCache *m, int fd) { |
690 | FileDescriptor *f; | |
691 | ||
bf807d4d | 692 | assert(m); |
fa6ac760 | 693 | assert(fd >= 0); |
bf807d4d | 694 | |
fa6ac760 LP |
695 | /* Make sure that any queued SIGBUS are first dispatched, so |
696 | * that we don't end up with a SIGBUS entry we cannot relate | |
697 | * to any existing memory map */ | |
698 | ||
699 | mmap_cache_process_sigbus(m); | |
700 | ||
701 | f = hashmap_get(m->fds, INT_TO_PTR(fd + 1)); | |
702 | if (!f) | |
703 | return; | |
704 | ||
705 | fd_free(f); | |
bf807d4d | 706 | } |