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1 #include "jemalloc/internal/jemalloc_preamble.h"
2 #include "jemalloc/internal/jemalloc_internal_includes.h"
3 
4 #include "jemalloc/internal/assert.h"
5 
6 #ifndef JEMALLOC_ZONE
7 #  error "This source file is for zones on Darwin (OS X)."
8 #endif
9 
10 /* Definitions of the following structs in malloc/malloc.h might be too old
11  * for the built binary to run on newer versions of OSX. So use the newest
12  * possible version of those structs.
13  */
14 typedef struct _malloc_zone_t {
15 	void *reserved1;
16 	void *reserved2;
17 	size_t (*size)(struct _malloc_zone_t *, const void *);
18 	void *(*malloc)(struct _malloc_zone_t *, size_t);
19 	void *(*calloc)(struct _malloc_zone_t *, size_t, size_t);
20 	void *(*valloc)(struct _malloc_zone_t *, size_t);
21 	void (*free)(struct _malloc_zone_t *, void *);
22 	void *(*realloc)(struct _malloc_zone_t *, void *, size_t);
23 	void (*destroy)(struct _malloc_zone_t *);
24 	const char *zone_name;
25 	unsigned (*batch_malloc)(struct _malloc_zone_t *, size_t, void **, unsigned);
26 	void (*batch_free)(struct _malloc_zone_t *, void **, unsigned);
27 	struct malloc_introspection_t *introspect;
28 	unsigned version;
29 	void *(*memalign)(struct _malloc_zone_t *, size_t, size_t);
30 	void (*free_definite_size)(struct _malloc_zone_t *, void *, size_t);
31 	size_t (*pressure_relief)(struct _malloc_zone_t *, size_t);
32 } malloc_zone_t;
33 
34 typedef struct {
35 	vm_address_t address;
36 	vm_size_t size;
37 } vm_range_t;
38 
39 typedef struct malloc_statistics_t {
40 	unsigned blocks_in_use;
41 	size_t size_in_use;
42 	size_t max_size_in_use;
43 	size_t size_allocated;
44 } malloc_statistics_t;
45 
46 typedef kern_return_t memory_reader_t(task_t, vm_address_t, vm_size_t, void **);
47 
48 typedef void vm_range_recorder_t(task_t, void *, unsigned type, vm_range_t *, unsigned);
49 
50 typedef struct malloc_introspection_t {
51 	kern_return_t (*enumerator)(task_t, void *, unsigned, vm_address_t, memory_reader_t, vm_range_recorder_t);
52 	size_t (*good_size)(malloc_zone_t *, size_t);
53 	boolean_t (*check)(malloc_zone_t *);
54 	void (*print)(malloc_zone_t *, boolean_t);
55 	void (*log)(malloc_zone_t *, void *);
56 	void (*force_lock)(malloc_zone_t *);
57 	void (*force_unlock)(malloc_zone_t *);
58 	void (*statistics)(malloc_zone_t *, malloc_statistics_t *);
59 	boolean_t (*zone_locked)(malloc_zone_t *);
60 	boolean_t (*enable_discharge_checking)(malloc_zone_t *);
61 	boolean_t (*disable_discharge_checking)(malloc_zone_t *);
62 	void (*discharge)(malloc_zone_t *, void *);
63 #ifdef __BLOCKS__
64 	void (*enumerate_discharged_pointers)(malloc_zone_t *, void (^)(void *, void *));
65 #else
66 	void *enumerate_unavailable_without_blocks;
67 #endif
68 	void (*reinit_lock)(malloc_zone_t *);
69 } malloc_introspection_t;
70 
71 extern kern_return_t malloc_get_all_zones(task_t, memory_reader_t, vm_address_t **, unsigned *);
72 
73 extern malloc_zone_t *malloc_default_zone(void);
74 
75 extern void malloc_zone_register(malloc_zone_t *zone);
76 
77 extern void malloc_zone_unregister(malloc_zone_t *zone);
78 
79 /*
80  * The malloc_default_purgeable_zone() function is only available on >= 10.6.
81  * We need to check whether it is present at runtime, thus the weak_import.
82  */
83 extern malloc_zone_t *malloc_default_purgeable_zone(void)
84 JEMALLOC_ATTR(weak_import);
85 
86 /******************************************************************************/
87 /* Data. */
88 
89 static malloc_zone_t *default_zone, *purgeable_zone;
90 static malloc_zone_t jemalloc_zone;
91 static struct malloc_introspection_t jemalloc_zone_introspect;
92 static pid_t zone_force_lock_pid = -1;
93 
94 /******************************************************************************/
95 /* Function prototypes for non-inline static functions. */
96 
97 static size_t	zone_size(malloc_zone_t *zone, const void *ptr);
98 static void	*zone_malloc(malloc_zone_t *zone, size_t size);
99 static void	*zone_calloc(malloc_zone_t *zone, size_t num, size_t size);
100 static void	*zone_valloc(malloc_zone_t *zone, size_t size);
101 static void	zone_free(malloc_zone_t *zone, void *ptr);
102 static void	*zone_realloc(malloc_zone_t *zone, void *ptr, size_t size);
103 static void	*zone_memalign(malloc_zone_t *zone, size_t alignment,
104     size_t size);
105 static void	zone_free_definite_size(malloc_zone_t *zone, void *ptr,
106     size_t size);
107 static void	zone_destroy(malloc_zone_t *zone);
108 static unsigned	zone_batch_malloc(struct _malloc_zone_t *zone, size_t size,
109     void **results, unsigned num_requested);
110 static void	zone_batch_free(struct _malloc_zone_t *zone,
111     void **to_be_freed, unsigned num_to_be_freed);
112 static size_t	zone_pressure_relief(struct _malloc_zone_t *zone, size_t goal);
113 static size_t	zone_good_size(malloc_zone_t *zone, size_t size);
114 static kern_return_t	zone_enumerator(task_t task, void *data, unsigned type_mask,
115     vm_address_t zone_address, memory_reader_t reader,
116     vm_range_recorder_t recorder);
117 static boolean_t	zone_check(malloc_zone_t *zone);
118 static void	zone_print(malloc_zone_t *zone, boolean_t verbose);
119 static void	zone_log(malloc_zone_t *zone, void *address);
120 static void	zone_force_lock(malloc_zone_t *zone);
121 static void	zone_force_unlock(malloc_zone_t *zone);
122 static void	zone_statistics(malloc_zone_t *zone,
123     malloc_statistics_t *stats);
124 static boolean_t	zone_locked(malloc_zone_t *zone);
125 static void	zone_reinit_lock(malloc_zone_t *zone);
126 
127 /******************************************************************************/
128 /*
129  * Functions.
130  */
131 
132 static size_t
zone_size(malloc_zone_t * zone,const void * ptr)133 zone_size(malloc_zone_t *zone, const void *ptr) {
134 	/*
135 	 * There appear to be places within Darwin (such as setenv(3)) that
136 	 * cause calls to this function with pointers that *no* zone owns.  If
137 	 * we knew that all pointers were owned by *some* zone, we could split
138 	 * our zone into two parts, and use one as the default allocator and
139 	 * the other as the default deallocator/reallocator.  Since that will
140 	 * not work in practice, we must check all pointers to assure that they
141 	 * reside within a mapped extent before determining size.
142 	 */
143 	return ivsalloc(tsdn_fetch(), ptr);
144 }
145 
146 static void *
zone_malloc(malloc_zone_t * zone,size_t size)147 zone_malloc(malloc_zone_t *zone, size_t size) {
148 	return je_malloc(size);
149 }
150 
151 static void *
zone_calloc(malloc_zone_t * zone,size_t num,size_t size)152 zone_calloc(malloc_zone_t *zone, size_t num, size_t size) {
153 	return je_calloc(num, size);
154 }
155 
156 static void *
zone_valloc(malloc_zone_t * zone,size_t size)157 zone_valloc(malloc_zone_t *zone, size_t size) {
158 	void *ret = NULL; /* Assignment avoids useless compiler warning. */
159 
160 	je_posix_memalign(&ret, PAGE, size);
161 
162 	return ret;
163 }
164 
165 static void
zone_free(malloc_zone_t * zone,void * ptr)166 zone_free(malloc_zone_t *zone, void *ptr) {
167 	if (ivsalloc(tsdn_fetch(), ptr) != 0) {
168 		je_free(ptr);
169 		return;
170 	}
171 
172 	free(ptr);
173 }
174 
175 static void *
zone_realloc(malloc_zone_t * zone,void * ptr,size_t size)176 zone_realloc(malloc_zone_t *zone, void *ptr, size_t size) {
177 	if (ivsalloc(tsdn_fetch(), ptr) != 0) {
178 		return je_realloc(ptr, size);
179 	}
180 
181 	return realloc(ptr, size);
182 }
183 
184 static void *
zone_memalign(malloc_zone_t * zone,size_t alignment,size_t size)185 zone_memalign(malloc_zone_t *zone, size_t alignment, size_t size) {
186 	void *ret = NULL; /* Assignment avoids useless compiler warning. */
187 
188 	je_posix_memalign(&ret, alignment, size);
189 
190 	return ret;
191 }
192 
193 static void
zone_free_definite_size(malloc_zone_t * zone,void * ptr,size_t size)194 zone_free_definite_size(malloc_zone_t *zone, void *ptr, size_t size) {
195 	size_t alloc_size;
196 
197 	alloc_size = ivsalloc(tsdn_fetch(), ptr);
198 	if (alloc_size != 0) {
199 		assert(alloc_size == size);
200 		je_free(ptr);
201 		return;
202 	}
203 
204 	free(ptr);
205 }
206 
207 static void
zone_destroy(malloc_zone_t * zone)208 zone_destroy(malloc_zone_t *zone) {
209 	/* This function should never be called. */
210 	not_reached();
211 }
212 
213 static unsigned
zone_batch_malloc(struct _malloc_zone_t * zone,size_t size,void ** results,unsigned num_requested)214 zone_batch_malloc(struct _malloc_zone_t *zone, size_t size, void **results,
215     unsigned num_requested) {
216 	unsigned i;
217 
218 	for (i = 0; i < num_requested; i++) {
219 		results[i] = je_malloc(size);
220 		if (!results[i])
221 			break;
222 	}
223 
224 	return i;
225 }
226 
227 static void
zone_batch_free(struct _malloc_zone_t * zone,void ** to_be_freed,unsigned num_to_be_freed)228 zone_batch_free(struct _malloc_zone_t *zone, void **to_be_freed,
229     unsigned num_to_be_freed) {
230 	unsigned i;
231 
232 	for (i = 0; i < num_to_be_freed; i++) {
233 		zone_free(zone, to_be_freed[i]);
234 		to_be_freed[i] = NULL;
235 	}
236 }
237 
238 static size_t
zone_pressure_relief(struct _malloc_zone_t * zone,size_t goal)239 zone_pressure_relief(struct _malloc_zone_t *zone, size_t goal) {
240 	return 0;
241 }
242 
243 static size_t
zone_good_size(malloc_zone_t * zone,size_t size)244 zone_good_size(malloc_zone_t *zone, size_t size) {
245 	if (size == 0) {
246 		size = 1;
247 	}
248 	return sz_s2u(size);
249 }
250 
251 static kern_return_t
zone_enumerator(task_t task,void * data,unsigned type_mask,vm_address_t zone_address,memory_reader_t reader,vm_range_recorder_t recorder)252 zone_enumerator(task_t task, void *data, unsigned type_mask,
253     vm_address_t zone_address, memory_reader_t reader,
254     vm_range_recorder_t recorder) {
255 	return KERN_SUCCESS;
256 }
257 
258 static boolean_t
zone_check(malloc_zone_t * zone)259 zone_check(malloc_zone_t *zone) {
260 	return true;
261 }
262 
263 static void
zone_print(malloc_zone_t * zone,boolean_t verbose)264 zone_print(malloc_zone_t *zone, boolean_t verbose) {
265 }
266 
267 static void
zone_log(malloc_zone_t * zone,void * address)268 zone_log(malloc_zone_t *zone, void *address) {
269 }
270 
271 static void
zone_force_lock(malloc_zone_t * zone)272 zone_force_lock(malloc_zone_t *zone) {
273 	if (isthreaded) {
274 		/*
275 		 * See the note in zone_force_unlock, below, to see why we need
276 		 * this.
277 		 */
278 		assert(zone_force_lock_pid == -1);
279 		zone_force_lock_pid = getpid();
280 		jemalloc_prefork();
281 	}
282 }
283 
284 static void
zone_force_unlock(malloc_zone_t * zone)285 zone_force_unlock(malloc_zone_t *zone) {
286 	/*
287 	 * zone_force_lock and zone_force_unlock are the entry points to the
288 	 * forking machinery on OS X.  The tricky thing is, the child is not
289 	 * allowed to unlock mutexes locked in the parent, even if owned by the
290 	 * forking thread (and the mutex type we use in OS X will fail an assert
291 	 * if we try).  In the child, we can get away with reinitializing all
292 	 * the mutexes, which has the effect of unlocking them.  In the parent,
293 	 * doing this would mean we wouldn't wake any waiters blocked on the
294 	 * mutexes we unlock.  So, we record the pid of the current thread in
295 	 * zone_force_lock, and use that to detect if we're in the parent or
296 	 * child here, to decide which unlock logic we need.
297 	 */
298 	if (isthreaded) {
299 		assert(zone_force_lock_pid != -1);
300 		if (getpid() == zone_force_lock_pid) {
301 			jemalloc_postfork_parent();
302 		} else {
303 			jemalloc_postfork_child();
304 		}
305 		zone_force_lock_pid = -1;
306 	}
307 }
308 
309 static void
zone_statistics(malloc_zone_t * zone,malloc_statistics_t * stats)310 zone_statistics(malloc_zone_t *zone, malloc_statistics_t *stats) {
311 	/* We make no effort to actually fill the values */
312 	stats->blocks_in_use = 0;
313 	stats->size_in_use = 0;
314 	stats->max_size_in_use = 0;
315 	stats->size_allocated = 0;
316 }
317 
318 static boolean_t
zone_locked(malloc_zone_t * zone)319 zone_locked(malloc_zone_t *zone) {
320 	/* Pretend no lock is being held */
321 	return false;
322 }
323 
324 static void
zone_reinit_lock(malloc_zone_t * zone)325 zone_reinit_lock(malloc_zone_t *zone) {
326 	/* As of OSX 10.12, this function is only used when force_unlock would
327 	 * be used if the zone version were < 9. So just use force_unlock. */
328 	zone_force_unlock(zone);
329 }
330 
331 static void
zone_init(void)332 zone_init(void) {
333 	jemalloc_zone.size = zone_size;
334 	jemalloc_zone.malloc = zone_malloc;
335 	jemalloc_zone.calloc = zone_calloc;
336 	jemalloc_zone.valloc = zone_valloc;
337 	jemalloc_zone.free = zone_free;
338 	jemalloc_zone.realloc = zone_realloc;
339 	jemalloc_zone.destroy = zone_destroy;
340 	jemalloc_zone.zone_name = "jemalloc_zone";
341 	jemalloc_zone.batch_malloc = zone_batch_malloc;
342 	jemalloc_zone.batch_free = zone_batch_free;
343 	jemalloc_zone.introspect = &jemalloc_zone_introspect;
344 	jemalloc_zone.version = 9;
345 	jemalloc_zone.memalign = zone_memalign;
346 	jemalloc_zone.free_definite_size = zone_free_definite_size;
347 	jemalloc_zone.pressure_relief = zone_pressure_relief;
348 
349 	jemalloc_zone_introspect.enumerator = zone_enumerator;
350 	jemalloc_zone_introspect.good_size = zone_good_size;
351 	jemalloc_zone_introspect.check = zone_check;
352 	jemalloc_zone_introspect.print = zone_print;
353 	jemalloc_zone_introspect.log = zone_log;
354 	jemalloc_zone_introspect.force_lock = zone_force_lock;
355 	jemalloc_zone_introspect.force_unlock = zone_force_unlock;
356 	jemalloc_zone_introspect.statistics = zone_statistics;
357 	jemalloc_zone_introspect.zone_locked = zone_locked;
358 	jemalloc_zone_introspect.enable_discharge_checking = NULL;
359 	jemalloc_zone_introspect.disable_discharge_checking = NULL;
360 	jemalloc_zone_introspect.discharge = NULL;
361 #ifdef __BLOCKS__
362 	jemalloc_zone_introspect.enumerate_discharged_pointers = NULL;
363 #else
364 	jemalloc_zone_introspect.enumerate_unavailable_without_blocks = NULL;
365 #endif
366 	jemalloc_zone_introspect.reinit_lock = zone_reinit_lock;
367 }
368 
369 static malloc_zone_t *
zone_default_get(void)370 zone_default_get(void) {
371 	malloc_zone_t **zones = NULL;
372 	unsigned int num_zones = 0;
373 
374 	/*
375 	 * On OSX 10.12, malloc_default_zone returns a special zone that is not
376 	 * present in the list of registered zones. That zone uses a "lite zone"
377 	 * if one is present (apparently enabled when malloc stack logging is
378 	 * enabled), or the first registered zone otherwise. In practice this
379 	 * means unless malloc stack logging is enabled, the first registered
380 	 * zone is the default.  So get the list of zones to get the first one,
381 	 * instead of relying on malloc_default_zone.
382 	 */
383 	if (KERN_SUCCESS != malloc_get_all_zones(0, NULL,
384 	    (vm_address_t**)&zones, &num_zones)) {
385 		/*
386 		 * Reset the value in case the failure happened after it was
387 		 * set.
388 		 */
389 		num_zones = 0;
390 	}
391 
392 	if (num_zones) {
393 		return zones[0];
394 	}
395 
396 	return malloc_default_zone();
397 }
398 
399 /* As written, this function can only promote jemalloc_zone. */
400 static void
zone_promote(void)401 zone_promote(void) {
402 	malloc_zone_t *zone;
403 
404 	do {
405 		/*
406 		 * Unregister and reregister the default zone.  On OSX >= 10.6,
407 		 * unregistering takes the last registered zone and places it
408 		 * at the location of the specified zone.  Unregistering the
409 		 * default zone thus makes the last registered one the default.
410 		 * On OSX < 10.6, unregistering shifts all registered zones.
411 		 * The first registered zone then becomes the default.
412 		 */
413 		malloc_zone_unregister(default_zone);
414 		malloc_zone_register(default_zone);
415 
416 		/*
417 		 * On OSX 10.6, having the default purgeable zone appear before
418 		 * the default zone makes some things crash because it thinks it
419 		 * owns the default zone allocated pointers.  We thus
420 		 * unregister/re-register it in order to ensure it's always
421 		 * after the default zone.  On OSX < 10.6, there is no purgeable
422 		 * zone, so this does nothing.  On OSX >= 10.6, unregistering
423 		 * replaces the purgeable zone with the last registered zone
424 		 * above, i.e. the default zone.  Registering it again then puts
425 		 * it at the end, obviously after the default zone.
426 		 */
427 		if (purgeable_zone != NULL) {
428 			malloc_zone_unregister(purgeable_zone);
429 			malloc_zone_register(purgeable_zone);
430 		}
431 
432 		zone = zone_default_get();
433 	} while (zone != &jemalloc_zone);
434 }
435 
JEMALLOC_ATTR(constructor)436 JEMALLOC_ATTR(constructor)
437 void
438 zone_register(void) {
439 	/*
440 	 * If something else replaced the system default zone allocator, don't
441 	 * register jemalloc's.
442 	 */
443 	default_zone = zone_default_get();
444 	if (!default_zone->zone_name || strcmp(default_zone->zone_name,
445 	    "DefaultMallocZone") != 0) {
446 		return;
447 	}
448 
449 	/*
450 	 * The default purgeable zone is created lazily by OSX's libc.  It uses
451 	 * the default zone when it is created for "small" allocations
452 	 * (< 15 KiB), but assumes the default zone is a scalable_zone.  This
453 	 * obviously fails when the default zone is the jemalloc zone, so
454 	 * malloc_default_purgeable_zone() is called beforehand so that the
455 	 * default purgeable zone is created when the default zone is still
456 	 * a scalable_zone.  As purgeable zones only exist on >= 10.6, we need
457 	 * to check for the existence of malloc_default_purgeable_zone() at
458 	 * run time.
459 	 */
460 	purgeable_zone = (malloc_default_purgeable_zone == NULL) ? NULL :
461 	    malloc_default_purgeable_zone();
462 
463 	/* Register the custom zone.  At this point it won't be the default. */
464 	zone_init();
465 	malloc_zone_register(&jemalloc_zone);
466 
467 	/* Promote the custom zone to be default. */
468 	zone_promote();
469 }
470