/* * Copyright (c) 2006 Apple Computer, Inc. All rights reserved. * * @APPLE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this * file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_LICENSE_HEADER_END@ */ #include <stdbool.h> #include <stdint.h> #include <stdio.h> #include <sys/types.h> #include <unistd.h> #include <mach/mach.h> struct page { struct page* other; char pad[4096-sizeof(void*)]; }; struct page p1 = { &p1 }; struct page p2 = { &p1 }; struct page p3 = { &p1 }; struct page p4 = { &p1 }; struct page p5 = { &p1 }; struct page p6 = { &p1 }; struct page p7 = { &p1 }; struct page p8 = { &p1 }; struct page p9 = { &p1 }; struct page p10 = { &p1 }; // // This dylib has 10 pages of data and each page will be adjusted // by dyld if this dylib is not loaded at its preferred address. // bool checkRebasing() { int dirtyPageCount = 0; vm_address_t start = (((uintptr_t)&p1) + 4095) & (-4096); vm_address_t end = (((uintptr_t)&p10) + 4095) & (-4096); task_port_t task; task_for_pid(mach_task_self(), getpid(), &task); for (vm_address_t addr = start; addr < end; addr += 4096) { integer_t disposition = 0; integer_t ref_count = 0; vm_map_page_query(task, start, &disposition, &ref_count); if ( disposition & VM_PAGE_QUERY_PAGE_DIRTY ) ++dirtyPageCount; } //fprintf(stderr, "dirtyPageCount=%d\n", dirtyPageCount); // if there are too many dirty pages, then dyld is inefficient return ( dirtyPageCount < 2 ); }