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#include "mem_map.h"
#include <sys/mman.h>
#include "utils.h"
/*
* 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 <sys/mman.h>
namespace art {
size_t ParseHex(const std::string& string) {
CHECK_EQ(8U, string.size());
const char* str = string.c_str();
char* end;
size_t value = strtoul(str, &end, 16);
CHECK(end != str) << "Failed to parse hexadecimal value from " << string;
CHECK(*end == '\0') << "Failed to parse hexadecimal value from " << string;
return value;
}
void CheckMapRequest(byte* addr, size_t length) {
#ifndef NDEBUG
if (addr == NULL) {
return;
}
size_t base = reinterpret_cast<size_t>(addr);
size_t limit = base + length;
std::string maps;
bool read = ReadFileToString("/proc/self/maps", &maps);
if (!read) {
PLOG(FATAL) << "Failed to read /proc/self/maps";
}
// Quick and dirty parse of output like shown below. We only focus
// on grabbing the two 32-bit hex values at the start of each line
// and will fail on wider addresses found on 64-bit systems.
// 00008000-0001f000 r-xp 00000000 b3:01 273 /system/bin/toolbox
// 0001f000-00021000 rw-p 00017000 b3:01 273 /system/bin/toolbox
// 00021000-00029000 rw-p 00000000 00:00 0 [heap]
// 40011000-40053000 r-xp 00000000 b3:01 1050 /system/lib/libc.so
// 40053000-40056000 rw-p 00042000 b3:01 1050 /system/lib/libc.so
// 40056000-40061000 rw-p 00000000 00:00 0
// 40061000-40063000 r-xp 00000000 b3:01 1107 /system/lib/libusbhost.so
// 40063000-40064000 rw-p 00002000 b3:01 1107 /system/lib/libusbhost.so
// 4009d000-400a0000 r-xp 00000000 b3:01 1022 /system/lib/liblog.so
// 400a0000-400a1000 rw-p 00003000 b3:01 1022 /system/lib/liblog.so
// 400b7000-400cc000 r-xp 00000000 b3:01 932 /system/lib/libm.so
// 400cc000-400cd000 rw-p 00015000 b3:01 932 /system/lib/libm.so
// 400cf000-400d0000 r--p 00000000 00:00 0
// 400e4000-400ec000 r--s 00000000 00:0b 388 /dev/__properties__ (deleted)
// 400ec000-400fa000 r-xp 00000000 b3:01 1101 /system/lib/libcutils.so
// 400fa000-400fb000 rw-p 0000e000 b3:01 1101 /system/lib/libcutils.so
// 400fb000-4010a000 rw-p 00000000 00:00 0
// 4010d000-4010e000 r-xp 00000000 b3:01 929 /system/lib/libstdc++.so
// 4010e000-4010f000 rw-p 00001000 b3:01 929 /system/lib/libstdc++.so
// b0001000-b0009000 r-xp 00001000 b3:01 1098 /system/bin/linker
// b0009000-b000a000 rw-p 00009000 b3:01 1098 /system/bin/linker
// b000a000-b0015000 rw-p 00000000 00:00 0
// bee35000-bee56000 rw-p 00000000 00:00 0 [stack]
// ffff0000-ffff1000 r-xp 00000000 00:00 0 [vectors]
for (size_t i = 0; i < maps.size(); i++) {
size_t remaining = maps.size() - i;
if (remaining < 8+1+8) { // 00008000-0001f000
LOG(FATAL) << "Failed to parse at pos " << i << "\n" << maps;
}
std::string start_str = maps.substr(i, 8);
std::string end_str = maps.substr(i+1+8, 8);
uint32_t start = ParseHex(start_str);
uint32_t end = ParseHex(end_str);
CHECK(!(base >= start && base < end) // start of new within old
&& !(limit > start && limit < end) // end of new within old
&& !(base <= start && limit > end)) // start/end of new includes all of old
<< StringPrintf("Requested region %08x-%08x overlaps with existing map %08x-%08x\n",
base, limit, start, end)
<< maps;
i += 8+1+8;
i = maps.find('\n', i);
CHECK(i != std::string::npos) << "Failed to find newline from pos " << i << "\n" << maps;
}
#endif
}
MemMap* MemMap::Map(byte* addr, size_t length, int prot) {
CHECK_NE(0U, length);
CHECK_NE(0, prot);
size_t page_aligned_size = RoundUp(length, kPageSize);
CheckMapRequest(addr, page_aligned_size);
byte* actual = reinterpret_cast<byte*>(mmap(addr,
page_aligned_size,
prot,
MAP_PRIVATE | MAP_ANONYMOUS,
-1,
0));
if (actual == MAP_FAILED) {
PLOG(ERROR) << "mmap failed";
return NULL;
}
return new MemMap(actual, length, actual, page_aligned_size);
}
MemMap* MemMap::Map(byte* addr, size_t length, int prot, int flags, int fd, off_t start) {
CHECK_NE(0U, length);
CHECK_NE(0, prot);
CHECK_NE(0, flags & (MAP_SHARED | MAP_PRIVATE));
// adjust to be page-aligned
int page_offset = start % kPageSize;
off_t page_aligned_offset = start - page_offset;
size_t page_aligned_size = RoundUp(length + page_offset, kPageSize);
CheckMapRequest(addr, page_aligned_size);
byte* actual = reinterpret_cast<byte*>(mmap(addr,
page_aligned_size,
prot,
flags,
fd,
page_aligned_offset));
if (actual == MAP_FAILED) {
PLOG(ERROR) << "mmap failed";
return NULL;
}
return new MemMap(actual + page_offset, length, actual, page_aligned_size);
}
MemMap::~MemMap() {
if (base_addr_ == NULL && base_length_ == 0) {
return;
}
int result = munmap(base_addr_, base_length_);
base_addr_ = NULL;
base_length_ = 0;
if (result == -1) {
PLOG(FATAL) << "munmap failed";
}
}
MemMap::MemMap(byte* addr, size_t length, void* base_addr, size_t base_length)
: addr_(addr), length_(length), base_addr_(base_addr), base_length_(base_length) {
CHECK(addr_ != NULL);
CHECK(length_ != 0);
CHECK(base_addr_ != NULL);
CHECK(base_length_ != 0);
};
} // namespace art
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