1/* 2 * Copyright (c) 2006 Apple Computer, Inc. All rights reserved. 3 * 4 * @APPLE_LICENSE_HEADER_START@ 5 * 6 * This file contains Original Code and/or Modifications of Original Code 7 * as defined in and that are subject to the Apple Public Source License 8 * Version 2.0 (the 'License'). You may not use this file except in 9 * compliance with the License. Please obtain a copy of the License at 10 * http://www.opensource.apple.com/apsl/ and read it before using this 11 * file. 12 * 13 * The Original Code and all software distributed under the License are 14 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 15 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 16 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 17 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 18 * Please see the License for the specific language governing rights and 19 * limitations under the License. 20 * 21 * @APPLE_LICENSE_HEADER_END@ 22 */ 23 24#include <errno.h> 25#include <libkern/OSMemoryNotification.h> 26#include <mach/mach.h> 27#include <notify.h> 28#include <stdlib.h> 29#include <sys/time.h> 30#include <dispatch/dispatch.h> 31#include <dispatch/private.h> 32 33const char *kOSMemoryNotificationName = "com.apple.system.memorystatus"; 34 35struct _OSMemoryNotification { 36 int token; 37 mach_port_t port; 38}; 39 40int 41OSMemoryNotificationCreate(OSMemoryNotificationRef *note) 42{ 43 OSMemoryNotificationRef ref = malloc(sizeof(struct _OSMemoryNotification)); 44 45 if (NULL == ref) { 46 return ENOMEM; 47 } 48 49 if (NOTIFY_STATUS_OK != notify_register_mach_port(kOSMemoryNotificationName, &ref->port, 0, &ref->token)) 50 return ENOMEM; 51 52 *note = ref; 53 54 return 0; 55} 56 57int 58OSMemoryNotificationDestroy(OSMemoryNotificationRef note) 59{ 60 if (NOTIFY_STATUS_OK != notify_cancel(note->token)) 61 return EINVAL; 62 63 if (KERN_SUCCESS != mach_port_deallocate(mach_task_self(), note->port)) 64 return EINVAL; 65 66 free(note); 67 68 return 0; 69} 70 71int 72OSMemoryNotificationWait(OSMemoryNotificationRef note, OSMemoryNotificationLevel *level) 73{ 74 return OSMemoryNotificationTimedWait(note, level, NULL); 75} 76 77static mach_msg_timeout_t 78abs_to_timeout(const struct timeval *abstime) 79{ 80 struct timeval rel, now; 81 82 gettimeofday(&now, NULL); 83 84 rel.tv_usec = abstime->tv_usec - now.tv_usec; 85 rel.tv_sec = abstime->tv_sec - now.tv_sec; 86 if (rel.tv_usec < 0) { 87 rel.tv_usec += 1000000; 88 rel.tv_sec--; 89 } 90 if (((int)rel.tv_sec < 0) || ((rel.tv_sec == 0) && (rel.tv_usec == 0))) { 91 return 0; 92 } 93 return rel.tv_sec * 1000 + rel.tv_usec / 1000; 94} 95 96int 97OSMemoryNotificationTimedWait(OSMemoryNotificationRef note, OSMemoryNotificationLevel *level, const struct timeval *abstime) 98{ 99 dispatch_semaphore_t sema = dispatch_semaphore_create(0); 100 dispatch_retain(sema); 101 102 dispatch_source_t memoryNotificationSource = dispatch_source_create(DISPATCH_SOURCE_TYPE_VM, 0, DISPATCH_VM_PRESSURE, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)); 103 dispatch_source_set_event_handler(memoryNotificationSource, ^{ 104 dispatch_semaphore_signal(sema); 105 dispatch_release(sema); 106 }); 107 108 dispatch_resume(memoryNotificationSource); 109 110 dispatch_time_t waitTime = DISPATCH_TIME_FOREVER; 111 if (abstime) { 112 mach_msg_timeout_t timeout = abs_to_timeout(abstime); 113 waitTime = dispatch_time(DISPATCH_TIME_NOW, timeout * 1e6); 114 } 115 116 long ret = dispatch_semaphore_wait(sema, waitTime); 117 118 dispatch_release(sema); 119 dispatch_release(memoryNotificationSource); 120 121 if (ret != 0) { 122 return ETIMEDOUT; 123 } 124 125 if (level) { 126 *level = OSMemoryNotificationLevelUrgent; 127 } 128 129 return 0; 130} 131 132OSMemoryNotificationLevel OSMemoryNotificationCurrentLevel(void) 133{ 134 return OSMemoryNotificationLevelNormal; 135} 136