1#define _GNU_SOURCE
2#include <sys/mman.h>
3#include <stdint.h>
4#include <stdio.h>
5#include <stdlib.h>
6#include <unistd.h>
7#include <string.h>
8#include <sys/time.h>
9#include <sys/resource.h>
10#include <syscall.h>
11#include <errno.h>
12#include <stdbool.h>
13
14#ifndef MLOCK_ONFAULT
15#define MLOCK_ONFAULT 1
16#endif
17
18#ifndef MCL_ONFAULT
19#define MCL_ONFAULT (MCL_FUTURE << 1)
20#endif
21
22static int mlock2_(void *start, size_t len, int flags)
23{
24#ifdef __NR_mlock2
25 return syscall(__NR_mlock2, start, len, flags);
26#else
27 errno = ENOSYS;
28 return -1;
29#endif
30}
31
32struct vm_boundaries {
33 unsigned long start;
34 unsigned long end;
35};
36
37static int get_vm_area(unsigned long addr, struct vm_boundaries *area)
38{
39 FILE *file;
40 int ret = 1;
41 char line[1024] = {0};
42 char *end_addr;
43 char *stop;
44 unsigned long start;
45 unsigned long end;
46
47 if (!area)
48 return ret;
49
50 file = fopen("/proc/self/maps", "r");
51 if (!file) {
52 perror("fopen");
53 return ret;
54 }
55
56 memset(area, 0, sizeof(struct vm_boundaries));
57
58 while(fgets(line, 1024, file)) {
59 end_addr = strchr(line, '-');
60 if (!end_addr) {
61 printf("cannot parse /proc/self/maps\n");
62 goto out;
63 }
64 *end_addr = '\0';
65 end_addr++;
66 stop = strchr(end_addr, ' ');
67 if (!stop) {
68 printf("cannot parse /proc/self/maps\n");
69 goto out;
70 }
71 stop = '\0';
72
73 sscanf(line, "%lx", &start);
74 sscanf(end_addr, "%lx", &end);
75
76 if (start <= addr && end > addr) {
77 area->start = start;
78 area->end = end;
79 ret = 0;
80 goto out;
81 }
82 }
83out:
84 fclose(file);
85 return ret;
86}
87
88static uint64_t get_pageflags(unsigned long addr)
89{
90 FILE *file;
91 uint64_t pfn;
92 unsigned long offset;
93
94 file = fopen("/proc/self/pagemap", "r");
95 if (!file) {
96 perror("fopen pagemap");
97 _exit(1);
98 }
99
100 offset = addr / getpagesize() * sizeof(pfn);
101
102 if (fseek(file, offset, SEEK_SET)) {
103 perror("fseek pagemap");
104 _exit(1);
105 }
106
107 if (fread(&pfn, sizeof(pfn), 1, file) != 1) {
108 perror("fread pagemap");
109 _exit(1);
110 }
111
112 fclose(file);
113 return pfn;
114}
115
116static uint64_t get_kpageflags(unsigned long pfn)
117{
118 uint64_t flags;
119 FILE *file;
120
121 file = fopen("/proc/kpageflags", "r");
122 if (!file) {
123 perror("fopen kpageflags");
124 _exit(1);
125 }
126
127 if (fseek(file, pfn * sizeof(flags), SEEK_SET)) {
128 perror("fseek kpageflags");
129 _exit(1);
130 }
131
132 if (fread(&flags, sizeof(flags), 1, file) != 1) {
133 perror("fread kpageflags");
134 _exit(1);
135 }
136
137 fclose(file);
138 return flags;
139}
140
141static FILE *seek_to_smaps_entry(unsigned long addr)
142{
143 FILE *file;
144 char *line = NULL;
145 size_t size = 0;
146 unsigned long start, end;
147 char perms[5];
148 unsigned long offset;
149 char dev[32];
150 unsigned long inode;
151 char path[BUFSIZ];
152
153 file = fopen("/proc/self/smaps", "r");
154 if (!file) {
155 perror("fopen smaps");
156 _exit(1);
157 }
158
159 while (getline(&line, &size, file) > 0) {
160 if (sscanf(line, "%lx-%lx %s %lx %s %lu %s\n",
161 &start, &end, perms, &offset, dev, &inode, path) < 6)
162 goto next;
163
164 if (start <= addr && addr < end)
165 goto out;
166
167next:
168 free(line);
169 line = NULL;
170 size = 0;
171 }
172
173 fclose(file);
174 file = NULL;
175
176out:
177 free(line);
178 return file;
179}
180
181#define VMFLAGS "VmFlags:"
182
183static bool is_vmflag_set(unsigned long addr, const char *vmflag)
184{
185 char *line = NULL;
186 char *flags;
187 size_t size = 0;
188 bool ret = false;
189 FILE *smaps;
190
191 smaps = seek_to_smaps_entry(addr);
192 if (!smaps) {
193 printf("Unable to parse /proc/self/smaps\n");
194 goto out;
195 }
196
197 while (getline(&line, &size, smaps) > 0) {
198 if (!strstr(line, VMFLAGS)) {
199 free(line);
200 line = NULL;
201 size = 0;
202 continue;
203 }
204
205 flags = line + strlen(VMFLAGS);
206 ret = (strstr(flags, vmflag) != NULL);
207 goto out;
208 }
209
210out:
211 free(line);
212 fclose(smaps);
213 return ret;
214}
215
216#define SIZE "Size:"
217#define RSS "Rss:"
218#define LOCKED "lo"
219
220static bool is_vma_lock_on_fault(unsigned long addr)
221{
222 bool ret = false;
223 bool locked;
224 FILE *smaps = NULL;
225 unsigned long vma_size, vma_rss;
226 char *line = NULL;
227 char *value;
228 size_t size = 0;
229
230 locked = is_vmflag_set(addr, LOCKED);
231 if (!locked)
232 goto out;
233
234 smaps = seek_to_smaps_entry(addr);
235 if (!smaps) {
236 printf("Unable to parse /proc/self/smaps\n");
237 goto out;
238 }
239
240 while (getline(&line, &size, smaps) > 0) {
241 if (!strstr(line, SIZE)) {
242 free(line);
243 line = NULL;
244 size = 0;
245 continue;
246 }
247
248 value = line + strlen(SIZE);
249 if (sscanf(value, "%lu kB", &vma_size) < 1) {
250 printf("Unable to parse smaps entry for Size\n");
251 goto out;
252 }
253 break;
254 }
255
256 while (getline(&line, &size, smaps) > 0) {
257 if (!strstr(line, RSS)) {
258 free(line);
259 line = NULL;
260 size = 0;
261 continue;
262 }
263
264 value = line + strlen(RSS);
265 if (sscanf(value, "%lu kB", &vma_rss) < 1) {
266 printf("Unable to parse smaps entry for Rss\n");
267 goto out;
268 }
269 break;
270 }
271
272 ret = locked && (vma_rss < vma_size);
273out:
274 free(line);
275 if (smaps)
276 fclose(smaps);
277 return ret;
278}
279
280#define PRESENT_BIT 0x8000000000000000ULL
281#define PFN_MASK 0x007FFFFFFFFFFFFFULL
282#define UNEVICTABLE_BIT (1UL << 18)
283
284static int lock_check(char *map)
285{
286 unsigned long page_size = getpagesize();
287 uint64_t page1_flags, page2_flags;
288
289 page1_flags = get_pageflags((unsigned long)map);
290 page2_flags = get_pageflags((unsigned long)map + page_size);
291
292
293 if (((page1_flags & PRESENT_BIT) == 0) ||
294 ((page2_flags & PRESENT_BIT) == 0)) {
295 printf("Failed to make both pages present\n");
296 return 1;
297 }
298
299 page1_flags = get_kpageflags(page1_flags & PFN_MASK);
300 page2_flags = get_kpageflags(page2_flags & PFN_MASK);
301
302
303 if (((page1_flags & UNEVICTABLE_BIT) == 0) ||
304 ((page2_flags & UNEVICTABLE_BIT) == 0)) {
305 printf("Failed to make both pages unevictable\n");
306 return 1;
307 }
308
309 if (!is_vmflag_set((unsigned long)map, LOCKED)) {
310 printf("VMA flag %s is missing on page 1\n", LOCKED);
311 return 1;
312 }
313
314 if (!is_vmflag_set((unsigned long)map + page_size, LOCKED)) {
315 printf("VMA flag %s is missing on page 2\n", LOCKED);
316 return 1;
317 }
318
319 return 0;
320}
321
322static int unlock_lock_check(char *map)
323{
324 unsigned long page_size = getpagesize();
325 uint64_t page1_flags, page2_flags;
326
327 page1_flags = get_pageflags((unsigned long)map);
328 page2_flags = get_pageflags((unsigned long)map + page_size);
329 page1_flags = get_kpageflags(page1_flags & PFN_MASK);
330 page2_flags = get_kpageflags(page2_flags & PFN_MASK);
331
332 if ((page1_flags & UNEVICTABLE_BIT) || (page2_flags & UNEVICTABLE_BIT)) {
333 printf("A page is still marked unevictable after unlock\n");
334 return 1;
335 }
336
337 if (is_vmflag_set((unsigned long)map, LOCKED)) {
338 printf("VMA flag %s is present on page 1 after unlock\n", LOCKED);
339 return 1;
340 }
341
342 if (is_vmflag_set((unsigned long)map + page_size, LOCKED)) {
343 printf("VMA flag %s is present on page 2 after unlock\n", LOCKED);
344 return 1;
345 }
346
347 return 0;
348}
349
350static int test_mlock_lock()
351{
352 char *map;
353 int ret = 1;
354 unsigned long page_size = getpagesize();
355
356 map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
357 MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
358 if (map == MAP_FAILED) {
359 perror("test_mlock_locked mmap");
360 goto out;
361 }
362
363 if (mlock2_(map, 2 * page_size, 0)) {
364 if (errno == ENOSYS) {
365 printf("Cannot call new mlock family, skipping test\n");
366 _exit(0);
367 }
368 perror("mlock2(0)");
369 goto unmap;
370 }
371
372 if (lock_check(map))
373 goto unmap;
374
375
376 if (munlock(map, 2 * page_size)) {
377 perror("munlock()");
378 goto unmap;
379 }
380
381 ret = unlock_lock_check(map);
382
383unmap:
384 munmap(map, 2 * page_size);
385out:
386 return ret;
387}
388
389static int onfault_check(char *map)
390{
391 unsigned long page_size = getpagesize();
392 uint64_t page1_flags, page2_flags;
393
394 page1_flags = get_pageflags((unsigned long)map);
395 page2_flags = get_pageflags((unsigned long)map + page_size);
396
397
398 if ((page1_flags & PRESENT_BIT) || (page2_flags & PRESENT_BIT)) {
399 printf("Pages were made present by MLOCK_ONFAULT\n");
400 return 1;
401 }
402
403 *map = 'a';
404 page1_flags = get_pageflags((unsigned long)map);
405 page2_flags = get_pageflags((unsigned long)map + page_size);
406
407
408 if ((page1_flags & PRESENT_BIT) == 0) {
409 printf("Page 1 is not present after fault\n");
410 return 1;
411 } else if (page2_flags & PRESENT_BIT) {
412 printf("Page 2 was made present\n");
413 return 1;
414 }
415
416 page1_flags = get_kpageflags(page1_flags & PFN_MASK);
417
418
419 if ((page1_flags & UNEVICTABLE_BIT) == 0) {
420 printf("Failed to make faulted page unevictable\n");
421 return 1;
422 }
423
424 if (!is_vma_lock_on_fault((unsigned long)map)) {
425 printf("VMA is not marked for lock on fault\n");
426 return 1;
427 }
428
429 if (!is_vma_lock_on_fault((unsigned long)map + page_size)) {
430 printf("VMA is not marked for lock on fault\n");
431 return 1;
432 }
433
434 return 0;
435}
436
437static int unlock_onfault_check(char *map)
438{
439 unsigned long page_size = getpagesize();
440 uint64_t page1_flags;
441
442 page1_flags = get_pageflags((unsigned long)map);
443 page1_flags = get_kpageflags(page1_flags & PFN_MASK);
444
445 if (page1_flags & UNEVICTABLE_BIT) {
446 printf("Page 1 is still marked unevictable after unlock\n");
447 return 1;
448 }
449
450 if (is_vma_lock_on_fault((unsigned long)map) ||
451 is_vma_lock_on_fault((unsigned long)map + page_size)) {
452 printf("VMA is still lock on fault after unlock\n");
453 return 1;
454 }
455
456 return 0;
457}
458
459static int test_mlock_onfault()
460{
461 char *map;
462 int ret = 1;
463 unsigned long page_size = getpagesize();
464
465 map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
466 MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
467 if (map == MAP_FAILED) {
468 perror("test_mlock_locked mmap");
469 goto out;
470 }
471
472 if (mlock2_(map, 2 * page_size, MLOCK_ONFAULT)) {
473 if (errno == ENOSYS) {
474 printf("Cannot call new mlock family, skipping test\n");
475 _exit(0);
476 }
477 perror("mlock2(MLOCK_ONFAULT)");
478 goto unmap;
479 }
480
481 if (onfault_check(map))
482 goto unmap;
483
484
485 if (munlock(map, 2 * page_size)) {
486 if (errno == ENOSYS) {
487 printf("Cannot call new mlock family, skipping test\n");
488 _exit(0);
489 }
490 perror("munlock()");
491 goto unmap;
492 }
493
494 ret = unlock_onfault_check(map);
495unmap:
496 munmap(map, 2 * page_size);
497out:
498 return ret;
499}
500
501static int test_lock_onfault_of_present()
502{
503 char *map;
504 int ret = 1;
505 unsigned long page_size = getpagesize();
506 uint64_t page1_flags, page2_flags;
507
508 map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
509 MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
510 if (map == MAP_FAILED) {
511 perror("test_mlock_locked mmap");
512 goto out;
513 }
514
515 *map = 'a';
516
517 if (mlock2_(map, 2 * page_size, MLOCK_ONFAULT)) {
518 if (errno == ENOSYS) {
519 printf("Cannot call new mlock family, skipping test\n");
520 _exit(0);
521 }
522 perror("mlock2(MLOCK_ONFAULT)");
523 goto unmap;
524 }
525
526 page1_flags = get_pageflags((unsigned long)map);
527 page2_flags = get_pageflags((unsigned long)map + page_size);
528 page1_flags = get_kpageflags(page1_flags & PFN_MASK);
529 page2_flags = get_kpageflags(page2_flags & PFN_MASK);
530
531
532 if ((page1_flags & UNEVICTABLE_BIT) == 0) {
533 printf("Failed to make present page unevictable\n");
534 goto unmap;
535 }
536
537 if (!is_vma_lock_on_fault((unsigned long)map) ||
538 !is_vma_lock_on_fault((unsigned long)map + page_size)) {
539 printf("VMA with present pages is not marked lock on fault\n");
540 goto unmap;
541 }
542 ret = 0;
543unmap:
544 munmap(map, 2 * page_size);
545out:
546 return ret;
547}
548
549static int test_munlockall()
550{
551 char *map;
552 int ret = 1;
553 unsigned long page_size = getpagesize();
554
555 map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
556 MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
557
558 if (map == MAP_FAILED) {
559 perror("test_munlockall mmap");
560 goto out;
561 }
562
563 if (mlockall(MCL_CURRENT)) {
564 perror("mlockall(MCL_CURRENT)");
565 goto out;
566 }
567
568 if (lock_check(map))
569 goto unmap;
570
571 if (munlockall()) {
572 perror("munlockall()");
573 goto unmap;
574 }
575
576 if (unlock_lock_check(map))
577 goto unmap;
578
579 munmap(map, 2 * page_size);
580
581 map = mmap(NULL, 2 * page_size, PROT_READ | PROT_WRITE,
582 MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
583
584 if (map == MAP_FAILED) {
585 perror("test_munlockall second mmap");
586 goto out;
587 }
588
589 if (mlockall(MCL_CURRENT | MCL_ONFAULT)) {
590 perror("mlockall(MCL_CURRENT | MCL_ONFAULT)");
591 goto unmap;
592 }
593
594 if (onfault_check(map))
595 goto unmap;
596
597 if (munlockall()) {
598 perror("munlockall()");
599 goto unmap;
600 }
601
602 if (unlock_onfault_check(map))
603 goto unmap;
604
605 if (mlockall(MCL_CURRENT | MCL_FUTURE)) {
606 perror("mlockall(MCL_CURRENT | MCL_FUTURE)");
607 goto out;
608 }
609
610 if (lock_check(map))
611 goto unmap;
612
613 if (munlockall()) {
614 perror("munlockall()");
615 goto unmap;
616 }
617
618 ret = unlock_lock_check(map);
619
620unmap:
621 munmap(map, 2 * page_size);
622out:
623 munlockall();
624 return ret;
625}
626
627static int test_vma_management(bool call_mlock)
628{
629 int ret = 1;
630 void *map;
631 unsigned long page_size = getpagesize();
632 struct vm_boundaries page1;
633 struct vm_boundaries page2;
634 struct vm_boundaries page3;
635
636 map = mmap(NULL, 3 * page_size, PROT_READ | PROT_WRITE,
637 MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
638 if (map == MAP_FAILED) {
639 perror("mmap()");
640 return ret;
641 }
642
643 if (call_mlock && mlock2_(map, 3 * page_size, MLOCK_ONFAULT)) {
644 if (errno == ENOSYS) {
645 printf("Cannot call new mlock family, skipping test\n");
646 _exit(0);
647 }
648 perror("mlock(ONFAULT)\n");
649 goto out;
650 }
651
652 if (get_vm_area((unsigned long)map, &page1) ||
653 get_vm_area((unsigned long)map + page_size, &page2) ||
654 get_vm_area((unsigned long)map + page_size * 2, &page3)) {
655 printf("couldn't find mapping in /proc/self/maps\n");
656 goto out;
657 }
658
659
660
661
662
663
664 if (page1.start != page2.start || page2.start != page3.start) {
665 printf("VMAs are not merged to start, aborting test\n");
666 ret = 0;
667 goto out;
668 }
669
670 if (munlock(map + page_size, page_size)) {
671 perror("munlock()");
672 goto out;
673 }
674
675 if (get_vm_area((unsigned long)map, &page1) ||
676 get_vm_area((unsigned long)map + page_size, &page2) ||
677 get_vm_area((unsigned long)map + page_size * 2, &page3)) {
678 printf("couldn't find mapping in /proc/self/maps\n");
679 goto out;
680 }
681
682
683 if (page1.start == page2.start || page2.start == page3.start) {
684 printf("failed to split VMA for munlock\n");
685 goto out;
686 }
687
688
689 if (munlock(map, page_size * 3)) {
690 perror("munlock()");
691 goto out;
692 }
693
694 if (get_vm_area((unsigned long)map, &page1) ||
695 get_vm_area((unsigned long)map + page_size, &page2) ||
696 get_vm_area((unsigned long)map + page_size * 2, &page3)) {
697 printf("couldn't find mapping in /proc/self/maps\n");
698 goto out;
699 }
700
701
702 if (page1.start != page2.start || page2.start != page3.start) {
703 printf("failed to merge VMAs after munlock\n");
704 goto out;
705 }
706
707 ret = 0;
708out:
709 munmap(map, 3 * page_size);
710 return ret;
711}
712
713static int test_mlockall(int (test_function)(bool call_mlock))
714{
715 int ret = 1;
716
717 if (mlockall(MCL_CURRENT | MCL_ONFAULT | MCL_FUTURE)) {
718 perror("mlockall");
719 return ret;
720 }
721
722 ret = test_function(false);
723 munlockall();
724 return ret;
725}
726
727int main(int argc, char **argv)
728{
729 int ret = 0;
730 ret += test_mlock_lock();
731 ret += test_mlock_onfault();
732 ret += test_munlockall();
733 ret += test_lock_onfault_of_present();
734 ret += test_vma_management(true);
735 ret += test_mlockall(test_vma_management);
736 return ret;
737}
738
