runtime/mem_map.cc - platform/art - Git at Google

 /*
  * 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 <inttypes.h>
 #include <backtrace/BacktraceMap.h>

 #include "UniquePtr.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,
     std::pair<BacktraceMap::const_iterator, BacktraceMap::const_iterator> iters) {
   for (BacktraceMap::const_iterator it = iters.first; it != iters.second; ++it) {
     os << StringPrintf("0x%08x-0x%08x %c%c%c %s\n",
                        static_cast<uint32_t>(it->start),
                        static_cast<uint32_t>(it->end),
                        (it->flags & PROT_READ) ? 'r' : '-',
                        (it->flags & PROT_WRITE) ? 'w' : '-',
                        (it->flags & PROT_EXEC) ? 'x' : '-', it->name.c_str());
   }
   return os;
 }

 static void CheckMapRequest(byte* addr, size_t byte_count) {
   if (addr == NULL) {
     return;
   }

   uintptr_t base = reinterpret_cast<uintptr_t>(addr);
   uintptr_t limit = base + byte_count;

   UniquePtr<BacktraceMap> map(BacktraceMap::Create(getpid()));
   if (!map->Build()) {
     PLOG(WARNING) << "Failed to build process map";
     return;
   }
   for (BacktraceMap::const_iterator it = map->begin(); it != map->end(); ++it) {
     CHECK(!(base >= it->start && base < it->end)     // start of new within old
         && !(limit > it->start && limit < it->end)   // end of new within old
         && !(base <= it->start && limit > it->end))  // start/end of new includes all of old
         << StringPrintf("Requested region 0x%08" PRIxPTR "-0x%08" PRIxPTR " overlaps with "
                         "existing map 0x%08" PRIxPTR "-0x%08" PRIxPTR " (%s)\n",
                         base, limit,
                         static_cast<uintptr_t>(it->start), static_cast<uintptr_t>(it->end),
                         it->name.c_str())
         << std::make_pair(it, map->end());
   }
 }

 #else
 static void CheckMapRequest(byte*, size_t) { }
 #endif

 MemMap* MemMap::MapAnonymous(const char* name, byte* addr, size_t byte_count, int prot,
                              bool low_4gb, std::string* error_msg) {
   if (byte_count == 0) {
     return new MemMap(name, NULL, 0, NULL, 0, prot);
   }
   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) {
     *error_msg = StringPrintf("ashmem_create_region failed for '%s': %s", name, strerror(errno));
     return nullptr;
   }
 #else
   ScopedFd fd(-1);
   int flags = MAP_PRIVATE | MAP_ANONYMOUS;
 #endif
 #ifdef __LP64__
   if (low_4gb) {
     flags |= MAP_32BIT;
   }
 #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);
     *error_msg = StringPrintf("anonymous mmap(%p, %zd, %x, %x, %d, 0) failed\n%s",
                               addr, page_aligned_byte_count, prot, flags, fd.get(),
                               maps.c_str());
     return nullptr;
   }
   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, const char* filename,
                                  std::string* error_msg) {
   CHECK_NE(0, prot);
   CHECK_NE(0, flags & (MAP_SHARED | MAP_PRIVATE));
   if (byte_count == 0) {
     return new MemMap(filename, NULL, 0, NULL, 0, prot);
   }
   // 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 strerr(strerror(errno));
     std::string maps;
     ReadFileToString("/proc/self/maps", &maps);
     *error_msg = StringPrintf("mmap(%p, %zd, %x, %x, %d, %" PRId64 ") of file '%s' failed: %s\n%s",
                               page_aligned_addr, page_aligned_byte_count, prot, flags, fd,
                               static_cast<int64_t>(page_aligned_offset), filename, strerr.c_str(),
                               maps.c_str());
     return NULL;
   }
   return new MemMap(filename, 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) {
   if (size_ == 0) {
     CHECK(begin_ == NULL);
     CHECK(base_begin_ == NULL);
     CHECK_EQ(base_size_, 0U);
   } else {
     CHECK(begin_ != NULL);
     CHECK(base_begin_ != NULL);
     CHECK_NE(base_size_, 0U);
   }
 };

 MemMap* MemMap::RemapAtEnd(byte* new_end, const char* tail_name, int tail_prot,
                            std::string* error_msg) {
   DCHECK_GE(new_end, Begin());
   DCHECK_LE(new_end, End());
   DCHECK_LE(begin_ + size_, reinterpret_cast<byte*>(base_begin_) + base_size_);
   DCHECK(IsAligned<kPageSize>(begin_));
   DCHECK(IsAligned<kPageSize>(base_begin_));
   DCHECK(IsAligned<kPageSize>(reinterpret_cast<byte*>(base_begin_) + base_size_));
   DCHECK(IsAligned<kPageSize>(new_end));
   byte* old_end = begin_ + size_;
   byte* old_base_end = reinterpret_cast<byte*>(base_begin_) + base_size_;
   byte* new_base_end = new_end;
   DCHECK_LE(new_base_end, old_base_end);
   if (new_base_end == old_base_end) {
     return new MemMap(tail_name, NULL, 0, NULL, 0, tail_prot);
   }
   size_ = new_end - reinterpret_cast<byte*>(begin_);
   base_size_ = new_base_end - reinterpret_cast<byte*>(base_begin_);
   DCHECK_LE(begin_ + size_, reinterpret_cast<byte*>(base_begin_) + base_size_);
   size_t tail_size = old_end - new_end;
   byte* tail_base_begin = new_base_end;
   size_t tail_base_size = old_base_end - new_base_end;
   DCHECK_EQ(tail_base_begin + tail_base_size, old_base_end);
   DCHECK(IsAligned<kPageSize>(tail_base_size));

 #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 += tail_name;
   ScopedFd fd(ashmem_create_region(debug_friendly_name.c_str(), tail_base_size));
   int flags = MAP_PRIVATE;
   if (fd.get() == -1) {
     *error_msg = StringPrintf("ashmem_create_region failed for '%s': %s",
                               tail_name, strerror(errno));
     return nullptr;
   }
 #else
   ScopedFd fd(-1);
   int flags = MAP_PRIVATE | MAP_ANONYMOUS;
 #endif

   // Unmap/map the tail region.
   int result = munmap(tail_base_begin, tail_base_size);
   if (result == -1) {
     std::string maps;
     ReadFileToString("/proc/self/maps", &maps);
     *error_msg = StringPrintf("munmap(%p, %zd) failed for '%s'\n%s",
                               tail_base_begin, tail_base_size, name_.c_str(),
                               maps.c_str());
     return nullptr;
   }
   // Don't cause memory allocation between the munmap and the mmap
   // calls. Otherwise, libc (or something else) might take this memory
   // region. Note this isn't perfect as there's no way to prevent
   // other threads to try to take this memory region here.
   byte* actual = reinterpret_cast<byte*>(mmap(tail_base_begin, tail_base_size, tail_prot,
                                               flags, fd.get(), 0));
   if (actual == MAP_FAILED) {
     std::string maps;
     ReadFileToString("/proc/self/maps", &maps);
     *error_msg = StringPrintf("anonymous mmap(%p, %zd, %x, %x, %d, 0) failed\n%s",
                               tail_base_begin, tail_base_size, tail_prot, flags, fd.get(),
                               maps.c_str());
     return nullptr;
   }
   return new MemMap(tail_name, actual, tail_size, actual, tail_base_size, tail_prot);
 }

 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;
 }

 std::ostream& operator<<(std::ostream& os, const MemMap& mem_map) {
   os << StringPrintf("[MemMap: %s prot=%x %p-%p]",
                      mem_map.GetName().c_str(), mem_map.GetProtect(),
                      mem_map.BaseBegin(), mem_map.BaseEnd());
   return os;
 }

 }  // namespace art
	/*
	* 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 <inttypes.h>
	#include <backtrace/BacktraceMap.h>

	#include "UniquePtr.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,
	std::pair<BacktraceMap::const_iterator, BacktraceMap::const_iterator> iters) {
	for (BacktraceMap::const_iterator it = iters.first; it != iters.second; ++it) {
	os << StringPrintf("0x%08x-0x%08x %c%c%c %s\n",
	static_cast<uint32_t>(it->start),
	static_cast<uint32_t>(it->end),
	(it->flags & PROT_READ) ? 'r' : '-',
	(it->flags & PROT_WRITE) ? 'w' : '-',
	(it->flags & PROT_EXEC) ? 'x' : '-', it->name.c_str());
	}
	return os;
	}

	static void CheckMapRequest(byte* addr, size_t byte_count) {
	if (addr == NULL) {
	return;
	}

	uintptr_t base = reinterpret_cast<uintptr_t>(addr);
	uintptr_t limit = base + byte_count;

	UniquePtr<BacktraceMap> map(BacktraceMap::Create(getpid()));
	if (!map->Build()) {
	PLOG(WARNING) << "Failed to build process map";
	return;
	}
	for (BacktraceMap::const_iterator it = map->begin(); it != map->end(); ++it) {
	CHECK(!(base >= it->start && base < it->end) // start of new within old
	&& !(limit > it->start && limit < it->end) // end of new within old
	&& !(base <= it->start && limit > it->end)) // start/end of new includes all of old
	<< StringPrintf("Requested region 0x%08" PRIxPTR "-0x%08" PRIxPTR " overlaps with "
	"existing map 0x%08" PRIxPTR "-0x%08" PRIxPTR " (%s)\n",
	base, limit,
	static_cast<uintptr_t>(it->start), static_cast<uintptr_t>(it->end),
	it->name.c_str())
	<< std::make_pair(it, map->end());
	}
	}

	#else
	static void CheckMapRequest(byte*, size_t) { }
	#endif

	MemMap* MemMap::MapAnonymous(const char* name, byte* addr, size_t byte_count, int prot,
	bool low_4gb, std::string* error_msg) {
	if (byte_count == 0) {
	return new MemMap(name, NULL, 0, NULL, 0, prot);
	}
	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) {
	*error_msg = StringPrintf("ashmem_create_region failed for '%s': %s", name, strerror(errno));
	return nullptr;
	}
	#else
	ScopedFd fd(-1);
	int flags = MAP_PRIVATE \| MAP_ANONYMOUS;
	#endif
	#ifdef __LP64__
	if (low_4gb) {
	flags \|= MAP_32BIT;
	}
	#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);
	*error_msg = StringPrintf("anonymous mmap(%p, %zd, %x, %x, %d, 0) failed\n%s",
	addr, page_aligned_byte_count, prot, flags, fd.get(),
	maps.c_str());
	return nullptr;
	}
	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, const char* filename,
	std::string* error_msg) {
	CHECK_NE(0, prot);
	CHECK_NE(0, flags & (MAP_SHARED \| MAP_PRIVATE));
	if (byte_count == 0) {
	return new MemMap(filename, NULL, 0, NULL, 0, prot);
	}
	// 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 strerr(strerror(errno));
	std::string maps;
	ReadFileToString("/proc/self/maps", &maps);
	*error_msg = StringPrintf("mmap(%p, %zd, %x, %x, %d, %" PRId64 ") of file '%s' failed: %s\n%s",
	page_aligned_addr, page_aligned_byte_count, prot, flags, fd,
	static_cast<int64_t>(page_aligned_offset), filename, strerr.c_str(),
	maps.c_str());
	return NULL;
	}
	return new MemMap(filename, 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) {
	if (size_ == 0) {
	CHECK(begin_ == NULL);
	CHECK(base_begin_ == NULL);
	CHECK_EQ(base_size_, 0U);
	} else {
	CHECK(begin_ != NULL);
	CHECK(base_begin_ != NULL);
	CHECK_NE(base_size_, 0U);
	}
	};

	MemMap* MemMap::RemapAtEnd(byte* new_end, const char* tail_name, int tail_prot,
	std::string* error_msg) {
	DCHECK_GE(new_end, Begin());
	DCHECK_LE(new_end, End());
	DCHECK_LE(begin_ + size_, reinterpret_cast<byte*>(base_begin_) + base_size_);
	DCHECK(IsAligned<kPageSize>(begin_));
	DCHECK(IsAligned<kPageSize>(base_begin_));
	DCHECK(IsAligned<kPageSize>(reinterpret_cast<byte*>(base_begin_) + base_size_));
	DCHECK(IsAligned<kPageSize>(new_end));
	byte* old_end = begin_ + size_;
	byte* old_base_end = reinterpret_cast<byte*>(base_begin_) + base_size_;
	byte* new_base_end = new_end;
	DCHECK_LE(new_base_end, old_base_end);
	if (new_base_end == old_base_end) {
	return new MemMap(tail_name, NULL, 0, NULL, 0, tail_prot);
	}
	size_ = new_end - reinterpret_cast<byte*>(begin_);
	base_size_ = new_base_end - reinterpret_cast<byte*>(base_begin_);
	DCHECK_LE(begin_ + size_, reinterpret_cast<byte*>(base_begin_) + base_size_);
	size_t tail_size = old_end - new_end;
	byte* tail_base_begin = new_base_end;
	size_t tail_base_size = old_base_end - new_base_end;
	DCHECK_EQ(tail_base_begin + tail_base_size, old_base_end);
	DCHECK(IsAligned<kPageSize>(tail_base_size));

	#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 += tail_name;
	ScopedFd fd(ashmem_create_region(debug_friendly_name.c_str(), tail_base_size));
	int flags = MAP_PRIVATE;
	if (fd.get() == -1) {
	*error_msg = StringPrintf("ashmem_create_region failed for '%s': %s",
	tail_name, strerror(errno));
	return nullptr;
	}
	#else
	ScopedFd fd(-1);
	int flags = MAP_PRIVATE \| MAP_ANONYMOUS;
	#endif

	// Unmap/map the tail region.
	int result = munmap(tail_base_begin, tail_base_size);
	if (result == -1) {
	std::string maps;
	ReadFileToString("/proc/self/maps", &maps);
	*error_msg = StringPrintf("munmap(%p, %zd) failed for '%s'\n%s",
	tail_base_begin, tail_base_size, name_.c_str(),
	maps.c_str());
	return nullptr;
	}
	// Don't cause memory allocation between the munmap and the mmap
	// calls. Otherwise, libc (or something else) might take this memory
	// region. Note this isn't perfect as there's no way to prevent
	// other threads to try to take this memory region here.
	byte* actual = reinterpret_cast<byte*>(mmap(tail_base_begin, tail_base_size, tail_prot,
	flags, fd.get(), 0));
	if (actual == MAP_FAILED) {
	std::string maps;
	ReadFileToString("/proc/self/maps", &maps);
	*error_msg = StringPrintf("anonymous mmap(%p, %zd, %x, %x, %d, 0) failed\n%s",
	tail_base_begin, tail_base_size, tail_prot, flags, fd.get(),
	maps.c_str());
	return nullptr;
	}
	return new MemMap(tail_name, actual, tail_size, actual, tail_base_size, tail_prot);
	}

	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;
	}

	std::ostream& operator<<(std::ostream& os, const MemMap& mem_map) {
	os << StringPrintf("[MemMap: %s prot=%x %p-%p]",
	mem_map.GetName().c_str(), mem_map.GetProtect(),
	mem_map.BaseBegin(), mem_map.BaseEnd());
	return os;
	}

	} // namespace art