src/dyldNew.cpp

   1 /* -*- mode: C++; c-basic-offset: 4; tab-width: 4 -*-
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   3  * Copyright (c) 2004-2008 Apple Inc. All rights reserved.
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  24
  25
  26 #include <stdlib.h>
  27 #include <stdint.h>
  28 #include <string.h>
  29 #include <mach/mach.h>
  30 #include <sys/mman.h>
  31
  32 extern "C" void* __dso_handle;
  33
  34 #include "dyld.h"
  35 #include "dyldLibSystemInterface.h"
  36
  37 //
  38 //       dyld initially allocates all memory from a pool inside dyld.
  39 //   Once libSystem.dylib is initialized, dyld uses libSystem's malloc/free.
  40 //
  41
  42 #if __LP64__
  43         // room for about ~1000 initial dylibs
  44         #define DYLD_POOL_CHUNK_SIZE 200*1024
  45 #else
  46         // room for about ~900 initial dylibs
  47         #define DYLD_POOL_CHUNK_SIZE 150*1024
  48 #endif
  49
  50 struct dyld_static_pool {
  51         dyld_static_pool*       previousPool;
  52         uint8_t*                        current;
  53         uint8_t*                        end;
  54         uint8_t                         pool[1];
  55 };
  56
  57 // allocate initial pool independently of pool header to take less space on disk
  58 static uint8_t initialPoolContent[DYLD_POOL_CHUNK_SIZE] __attribute__((__aligned__(16)));
  59 static dyld_static_pool initialPool = { NULL, initialPoolContent, &initialPoolContent[DYLD_POOL_CHUNK_SIZE] };
  60 static dyld_static_pool* currentPool = &initialPool;
  61
  62
  63 void* malloc(size_t size)
  64 {
  65         if ( (dyld::gLibSystemHelpers != NULL) && dyld::gProcessInfo->libSystemInitialized ) {
  66                 void* p = dyld::gLibSystemHelpers->malloc(size);
  67                 //dyld::log("malloc(%lu) => %p from libSystem\n", size, p);
  68                 return p;
  69         }
  70         else {
  71                 if ( size > DYLD_POOL_CHUNK_SIZE ) {
  72                         dyld::log("dyld malloc overflow: size=%zu\n", size);
  73                         exit(1);
  74                 }
  75                 size = (size+sizeof(void*)-1) & (-sizeof(void*)); // pointer align
  76                 uint8_t* result = currentPool->current;
  77                 currentPool->current += size;
  78                 if ( currentPool->current > currentPool->end ) {
  79                         vm_address_t addr = 0;
  80                         kern_return_t r = vm_allocate(mach_task_self(), &addr, DYLD_POOL_CHUNK_SIZE, VM_FLAGS_ANYWHERE);
  81                         if ( r != KERN_SUCCESS ) {
  82                                 dyld::log("out of address space for dyld memory pool\n");
  83                                 exit(1);
  84                         }
  85                         dyld_static_pool* newPool = (dyld_static_pool*)addr;
  86                         newPool->previousPool = NULL;
  87                         newPool->current = newPool->pool;
  88                         newPool->end = (uint8_t*)(addr + DYLD_POOL_CHUNK_SIZE);
  89                         newPool->previousPool = currentPool;
  90                         currentPool = newPool;
  91                         if ( (currentPool->current + size) > currentPool->end ) {
  92                                 dyld::log("dyld memory pool exhausted: size=%lu\n", size);
  93                                 exit(1);
  94                         }
  95                         result = currentPool->current;
  96                         currentPool->current += size;
  97                 }
  98                 //dyld::log("%p = malloc(%3lu) from pool %p, free space = %lu\n", result, size, currentPool, (long)(currentPool->end - currentPool->current));
  99                 return result;
 100         }
 101 }
 102
 103
 104 void free(void* ptr)
 105 {
 106         // ignore any pointer within dyld (i.e. stuff from pool or static strings)
 107         if ( (dyld::gLibSystemHelpers != NULL) && ((ptr < &__dso_handle) || (ptr >= &initialPoolContent[DYLD_POOL_CHUNK_SIZE])) ) {
 108                 // ignore stuff in any dynamically alloated dyld pools
 109                 for (dyld_static_pool* p = currentPool; p != NULL; p = p->previousPool) {
 110                         if ( (p->pool <= ptr) && (ptr < p->end) ) {
 111                                 // do nothing, pool entries can't be reclaimed
 112                                 //dyld::log("free(%p) from dynamic pool\n", ptr);
 113                                 return;
 114                         }
 115                 }
 116
 117                 //dyld::log("free(%p) from libSystem\n", ptr);
 118                 return dyld::gLibSystemHelpers->free(ptr);
 119         }
 120         else {
 121                 // do nothing, pool entries can't be reclaimed
 122                 //dyld::log("free(%p) from static pool\n", ptr);
 123         }
 124 }
 125
 126
 127 void* calloc(size_t count, size_t size)
 128 {
 129         if ( dyld::gLibSystemHelpers != NULL ) {
 130                 void* result = dyld::gLibSystemHelpers->malloc(size*count);
 131                 bzero(result, size*count);
 132                 return result;
 133         }
 134         else {
 135                 // Check for overflow of integer multiplication
 136                 size_t total = count * size;
 137                 if ( total/count != size ) {
 138                         dyld::log("dyld calloc overflow: count=%zu, size=%zu\n", count, size);
 139                         exit(1);
 140                 }
 141                 return malloc(total);
 142         }
 143 }
 144
 145
 146 void* realloc(void *ptr, size_t size)
 147 {
 148         void* result = malloc(size);
 149         memcpy(result, ptr, size);
 150         return result;
 151 }
 152
 153 //     void* reallocf(void *ptr, size_t size);
 154 //     void* valloc(size_t size);
 155
 156 // needed __libc_init()
 157 extern "C" int _malloc_lock;
 158 int _malloc_lock = 0;
 159
 160
 161 // <rdar://problem/12857033> dyld calls this which uses libSystem.dylib's vm_allocate if available
 162 int vm_alloc(vm_address_t* addr, vm_size_t size, uint32_t flags)
 163 {
 164         if ( (dyld::gLibSystemHelpers != NULL) && (dyld::gLibSystemHelpers->version >= 12) ) {
 165                 return dyld::gLibSystemHelpers->vm_alloc(mach_task_self(), addr, size, flags);
 166         }
 167         else {
 168                 return ::vm_allocate(mach_task_self(), addr, size, flags);
 169         }
 170 }
 171
 172 void* xmmap(void* addr, size_t len, int prot, int flags, int fd, off_t offset)
 173 {
 174         if ( (dyld::gLibSystemHelpers != NULL) && (dyld::gLibSystemHelpers->version >= 12) ) {
 175                 return dyld::gLibSystemHelpers->mmap(addr, len, prot, flags, fd, offset);
 176         }
 177         else {
 178                 return ::mmap(addr, len, prot, flags, fd, offset);
 179         }
 180 }
 181
 182
 183