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/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "mem_map.h"
#include <corkscrew/map_info.h>
#include "base/stringprintf.h"
#include "ScopedFd.h"
#include "utils.h"
#define USE_ASHMEM 1
#ifdef USE_ASHMEM
#include <cutils/ashmem.h>
#endif
namespace art {
#if !defined(NDEBUG)
static std::ostream& operator<<(std::ostream& os, map_info_t* rhs) {
for (map_info_t* m = rhs; m != NULL; m = m->next) {
os << StringPrintf("0x%08x-0x%08x %c%c %s\n",
static_cast<uint32_t>(m->start),
static_cast<uint32_t>(m->end),
m->is_readable ? 'r' : '-', m->is_executable ? 'x' : '-', m->name);
}
return os;
}
static void CheckMapRequest(byte* addr, size_t byte_count) {
if (addr == NULL) {
return;
}
uint32_t base = reinterpret_cast<size_t>(addr);
uint32_t limit = base + byte_count;
map_info_t* map_info_list = load_map_info_list(getpid());
for (map_info_t* m = map_info_list; m != NULL; m = m->next) {
CHECK(!(base >= m->start && base < m->end) // start of new within old
&& !(limit > m->start && limit < m->end) // end of new within old
&& !(base <= m->start && limit > m->end)) // start/end of new includes all of old
<< StringPrintf("Requested region 0x%08x-0x%08x overlaps with existing map 0x%08x-0x%08x (%s)\n",
base, limit,
static_cast<uint32_t>(m->start), static_cast<uint32_t>(m->end), m->name)
<< map_info_list;
}
free_map_info_list(map_info_list);
}
#else
static void CheckMapRequest(byte*, size_t) { }
#endif
MemMap* MemMap::MapAnonymous(const char* name, byte* addr, size_t byte_count, int prot) {
CHECK_NE(0U, byte_count);
size_t page_aligned_byte_count = RoundUp(byte_count, kPageSize);
CheckMapRequest(addr, page_aligned_byte_count);
#ifdef USE_ASHMEM
// android_os_Debug.cpp read_mapinfo assumes all ashmem regions associated with the VM are
// prefixed "dalvik-".
std::string debug_friendly_name("dalvik-");
debug_friendly_name += name;
ScopedFd fd(ashmem_create_region(debug_friendly_name.c_str(), page_aligned_byte_count));
int flags = MAP_PRIVATE;
if (fd.get() == -1) {
PLOG(ERROR) << "ashmem_create_region failed (" << name << ")";
return NULL;
}
#else
ScopedFd fd(-1);
int flags = MAP_PRIVATE | MAP_ANONYMOUS;
#endif
byte* actual = reinterpret_cast<byte*>(mmap(addr, page_aligned_byte_count, prot, flags, fd.get(), 0));
if (actual == MAP_FAILED) {
std::string maps;
ReadFileToString("/proc/self/maps", &maps);
PLOG(ERROR) << "mmap(" << reinterpret_cast<void*>(addr) << ", " << page_aligned_byte_count
<< ", " << prot << ", " << flags << ", " << fd.get() << ", 0) failed for " << name
<< "\n" << maps;
return NULL;
}
return new MemMap(name, actual, byte_count, actual, page_aligned_byte_count, prot);
}
MemMap* MemMap::MapFileAtAddress(byte* addr, size_t byte_count,
int prot, int flags, int fd, off_t start, bool reuse) {
CHECK_NE(0U, byte_count);
CHECK_NE(0, prot);
CHECK_NE(0, flags & (MAP_SHARED | MAP_PRIVATE));
// Adjust 'offset' to be page-aligned as required by mmap.
int page_offset = start % kPageSize;
off_t page_aligned_offset = start - page_offset;
// Adjust 'byte_count' to be page-aligned as we will map this anyway.
size_t page_aligned_byte_count = RoundUp(byte_count + page_offset, kPageSize);
// The 'addr' is modified (if specified, ie non-null) to be page aligned to the file but not
// necessarily to virtual memory. mmap will page align 'addr' for us.
byte* page_aligned_addr = (addr == NULL) ? NULL : (addr - page_offset);
if (!reuse) {
// reuse means it is okay that it overlaps an existing page mapping.
// Only use this if you actually made the page reservation yourself.
CheckMapRequest(page_aligned_addr, page_aligned_byte_count);
} else {
CHECK(addr != NULL);
}
byte* actual = reinterpret_cast<byte*>(mmap(page_aligned_addr,
page_aligned_byte_count,
prot,
flags,
fd,
page_aligned_offset));
if (actual == MAP_FAILED) {
std::string maps;
ReadFileToString("/proc/self/maps", &maps);
PLOG(ERROR) << "mmap(" << reinterpret_cast<void*>(page_aligned_addr)
<< ", " << page_aligned_byte_count
<< ", " << prot << ", " << flags << ", " << fd << ", " << page_aligned_offset
<< ") failed\n" << maps;
return NULL;
}
return new MemMap("file", actual + page_offset, byte_count, actual, page_aligned_byte_count,
prot);
}
MemMap::~MemMap() {
if (base_begin_ == NULL && base_size_ == 0) {
return;
}
int result = munmap(base_begin_, base_size_);
if (result == -1) {
PLOG(FATAL) << "munmap failed";
}
}
MemMap::MemMap(const std::string& name, byte* begin, size_t size, void* base_begin,
size_t base_size, int prot)
: name_(name), begin_(begin), size_(size), base_begin_(base_begin), base_size_(base_size),
prot_(prot) {
CHECK(begin_ != NULL);
CHECK_NE(size_, 0U);
CHECK(base_begin_ != NULL);
CHECK_NE(base_size_, 0U);
};
void MemMap::UnMapAtEnd(byte* new_end) {
DCHECK_GE(new_end, Begin());
DCHECK_LE(new_end, End());
size_t unmap_size = End() - new_end;
munmap(new_end, unmap_size);
size_ -= unmap_size;
}
bool MemMap::Protect(int prot) {
if (base_begin_ == NULL && base_size_ == 0) {
prot_ = prot;
return true;
}
if (mprotect(base_begin_, base_size_, prot) == 0) {
prot_ = prot;
return true;
}
PLOG(ERROR) << "mprotect(" << reinterpret_cast<void*>(base_begin_) << ", " << base_size_ << ", "
<< prot << ") failed";
return false;
}
bool MemMap::ProtectRegion(uint8_t* addr, size_t length, int prot) {
CHECK_GE(addr, base_begin_);
CHECK_LT(addr + length, reinterpret_cast<const uint8_t*>(base_begin_) + base_size_);
/*
* Align "addr" to a page boundary and adjust "length" appropriately.
* (The address must be page-aligned, the length doesn't need to be,
* but we do need to ensure we cover the same range.)
*/
uint8_t* alignAddr = (uint8_t*) ((uintptr_t) addr & ~(kPageSize-1));
size_t alignLength = length + (addr - alignAddr);
if (mprotect(alignAddr, alignLength, prot) == 0) {
prot_ = prot;
return true;
}
PLOG(ERROR) << "mprotect(" << reinterpret_cast<void*>(alignAddr) << ", " << alignLength << ", "
<< prot << ") failed";
return false;
}
} // namespace art
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