Fix copy / move behaviour of Maps object.
Currently, moving or copying a Maps object leads to double free of MapInfo.
Even moving a Maps object did not prevent this, as after a move
the object only has to be in an "unspecified but valid state", which can
be the original state for a vector of raw pointers (but not for a vector
of unique_ptrs).
Changing to unique_ptrs is the most failsafe way to make sure we never
accidentally destruct MapInfo.
Test: atest libuwindstack_test
Failed LocalUnwinderTest#unwind_after_dlopen which also fails at master.
Change-Id: Id1c9739b334da5c1ba532fd55366e115940a66d3
diff --git a/libunwindstack/Global.cpp b/libunwindstack/Global.cpp
index fdfd705..a20be00 100644
--- a/libunwindstack/Global.cpp
+++ b/libunwindstack/Global.cpp
@@ -77,7 +77,7 @@
// f0000-f2000 0 r-- /system/lib/libc.so
// f2000-f3000 2000 rw- /system/lib/libc.so
MapInfo* map_start = nullptr;
- for (MapInfo* info : *maps) {
+ for (const auto& info : *maps) {
if (map_start != nullptr) {
if (map_start->name == info->name) {
if (info->offset != 0 &&
@@ -96,7 +96,7 @@
}
if (map_start == nullptr && (info->flags & PROT_READ) && info->offset == 0 &&
!info->name.empty()) {
- map_start = info;
+ map_start = info.get();
}
}
}
diff --git a/libunwindstack/Maps.cpp b/libunwindstack/Maps.cpp
index 1e4f72e..5da73e4 100644
--- a/libunwindstack/Maps.cpp
+++ b/libunwindstack/Maps.cpp
@@ -47,9 +47,9 @@
size_t last = maps_.size();
while (first < last) {
size_t index = (first + last) / 2;
- MapInfo* cur = maps_[index];
+ const auto& cur = maps_[index];
if (pc >= cur->start && pc < cur->end) {
- return cur;
+ return cur.get();
} else if (pc < cur->start) {
last = index;
} else {
@@ -67,34 +67,31 @@
if (strncmp(name, "/dev/", 5) == 0 && strncmp(name + 5, "ashmem/", 7) != 0) {
flags |= unwindstack::MAPS_FLAGS_DEVICE_MAP;
}
- maps_.push_back(
- new MapInfo(maps_.empty() ? nullptr : maps_.back(), start, end, pgoff, flags, name));
+ maps_.emplace_back(
+ new MapInfo(maps_.empty() ? nullptr : maps_.back().get(), start, end, pgoff,
+ flags, name));
});
}
void Maps::Add(uint64_t start, uint64_t end, uint64_t offset, uint64_t flags,
const std::string& name, uint64_t load_bias) {
- MapInfo* map_info =
- new MapInfo(maps_.empty() ? nullptr : maps_.back(), start, end, offset, flags, name);
+ auto map_info =
+ std::make_unique<MapInfo>(maps_.empty() ? nullptr : maps_.back().get(), start, end, offset,
+ flags, name);
map_info->load_bias = load_bias;
- maps_.push_back(map_info);
+ maps_.emplace_back(std::move(map_info));
}
void Maps::Sort() {
std::sort(maps_.begin(), maps_.end(),
- [](const MapInfo* a, const MapInfo* b) { return a->start < b->start; });
+ [](const std::unique_ptr<MapInfo>& a, const std::unique_ptr<MapInfo>& b) {
+ return a->start < b->start; });
// Set the prev_map values on the info objects.
MapInfo* prev_map = nullptr;
- for (MapInfo* map_info : maps_) {
+ for (const auto& map_info : maps_) {
map_info->prev_map = prev_map;
- prev_map = map_info;
- }
-}
-
-Maps::~Maps() {
- for (auto& map : maps_) {
- delete map;
+ prev_map = map_info.get();
}
}
@@ -107,8 +104,9 @@
if (strncmp(name, "/dev/", 5) == 0 && strncmp(name + 5, "ashmem/", 7) != 0) {
flags |= unwindstack::MAPS_FLAGS_DEVICE_MAP;
}
- maps_.push_back(
- new MapInfo(maps_.empty() ? nullptr : maps_.back(), start, end, pgoff, flags, name));
+ maps_.emplace_back(
+ new MapInfo(maps_.empty() ? nullptr : maps_.back().get(), start, end, pgoff,
+ flags, name));
});
}
@@ -124,10 +122,6 @@
// New maps will be added at the end without deleting the old ones.
size_t last_map_idx = maps_.size();
if (!Parse()) {
- // Delete any maps added by the Parse call.
- for (size_t i = last_map_idx; i < maps_.size(); i++) {
- delete maps_[i];
- }
maps_.resize(last_map_idx);
return false;
}
@@ -135,17 +129,16 @@
size_t total_entries = maps_.size();
size_t search_map_idx = 0;
for (size_t new_map_idx = last_map_idx; new_map_idx < maps_.size(); new_map_idx++) {
- MapInfo* new_map_info = maps_[new_map_idx];
+ auto& new_map_info = maps_[new_map_idx];
uint64_t start = new_map_info->start;
uint64_t end = new_map_info->end;
uint64_t flags = new_map_info->flags;
std::string* name = &new_map_info->name;
for (size_t old_map_idx = search_map_idx; old_map_idx < last_map_idx; old_map_idx++) {
- MapInfo* info = maps_[old_map_idx];
+ auto& info = maps_[old_map_idx];
if (start == info->start && end == info->end && flags == info->flags && *name == info->name) {
// No need to check
search_map_idx = old_map_idx + 1;
- delete new_map_info;
maps_[new_map_idx] = nullptr;
total_entries--;
break;
@@ -158,7 +151,7 @@
// Never delete these maps, they may be in use. The assumption is
// that there will only every be a handfull of these so waiting
// to destroy them is not too expensive.
- saved_maps_.push_back(info);
+ saved_maps_.emplace_back(std::move(info));
maps_[old_map_idx] = nullptr;
total_entries--;
}
@@ -169,14 +162,14 @@
// Now move out any of the maps that never were found.
for (size_t i = search_map_idx; i < last_map_idx; i++) {
- saved_maps_.push_back(maps_[i]);
+ saved_maps_.emplace_back(std::move(maps_[i]));
maps_[i] = nullptr;
total_entries--;
}
// Sort all of the values such that the nullptrs wind up at the end, then
// resize them away.
- std::sort(maps_.begin(), maps_.end(), [](const auto* a, const auto* b) {
+ std::sort(maps_.begin(), maps_.end(), [](const auto& a, const auto& b) {
if (a == nullptr) {
return false;
} else if (b == nullptr) {
@@ -189,10 +182,4 @@
return true;
}
-LocalUpdatableMaps::~LocalUpdatableMaps() {
- for (auto map_info : saved_maps_) {
- delete map_info;
- }
-}
-
} // namespace unwindstack
diff --git a/libunwindstack/benchmarks/unwind_benchmarks.cpp b/libunwindstack/benchmarks/unwind_benchmarks.cpp
index 8caecc7..de9137a 100644
--- a/libunwindstack/benchmarks/unwind_benchmarks.cpp
+++ b/libunwindstack/benchmarks/unwind_benchmarks.cpp
@@ -92,9 +92,9 @@
// Find the libc.so share library and use that for benchmark purposes.
*build_id_map_info = nullptr;
- for (unwindstack::MapInfo* map_info : maps) {
+ for (auto& map_info : maps) {
if (map_info->offset == 0 && map_info->GetBuildID() != "") {
- *build_id_map_info = map_info;
+ *build_id_map_info = map_info.get();
break;
}
}
diff --git a/libunwindstack/include/unwindstack/Maps.h b/libunwindstack/include/unwindstack/Maps.h
index 67fbed2..1784394 100644
--- a/libunwindstack/include/unwindstack/Maps.h
+++ b/libunwindstack/include/unwindstack/Maps.h
@@ -20,6 +20,7 @@
#include <sys/types.h>
#include <unistd.h>
+#include <memory>
#include <string>
#include <vector>
@@ -37,8 +38,16 @@
class Maps {
public:
+ virtual ~Maps() = default;
+
Maps() = default;
- virtual ~Maps();
+
+ // Maps are not copyable but movable, because they own pointers to MapInfo
+ // objects.
+ Maps(const Maps&) = delete;
+ Maps& operator=(const Maps&) = delete;
+ Maps(Maps&&) = default;
+ Maps& operator=(Maps&&) = default;
MapInfo* Find(uint64_t pc);
@@ -51,11 +60,11 @@
void Sort();
- typedef std::vector<MapInfo*>::iterator iterator;
+ typedef std::vector<std::unique_ptr<MapInfo>>::iterator iterator;
iterator begin() { return maps_.begin(); }
iterator end() { return maps_.end(); }
- typedef std::vector<MapInfo*>::const_iterator const_iterator;
+ typedef std::vector<std::unique_ptr<MapInfo>>::const_iterator const_iterator;
const_iterator begin() const { return maps_.begin(); }
const_iterator end() const { return maps_.end(); }
@@ -63,11 +72,11 @@
MapInfo* Get(size_t index) {
if (index >= maps_.size()) return nullptr;
- return maps_[index];
+ return maps_[index].get();
}
protected:
- std::vector<MapInfo*> maps_;
+ std::vector<std::unique_ptr<MapInfo>> maps_;
};
class RemoteMaps : public Maps {
@@ -90,14 +99,14 @@
class LocalUpdatableMaps : public Maps {
public:
LocalUpdatableMaps() : Maps() {}
- virtual ~LocalUpdatableMaps();
+ virtual ~LocalUpdatableMaps() = default;
bool Reparse();
const std::string GetMapsFile() const override;
private:
- std::vector<MapInfo*> saved_maps_;
+ std::vector<std::unique_ptr<MapInfo>> saved_maps_;
};
class BufferMaps : public Maps {
diff --git a/libunwindstack/tests/MapsTest.cpp b/libunwindstack/tests/MapsTest.cpp
index b4197f2..9e7a6ab 100644
--- a/libunwindstack/tests/MapsTest.cpp
+++ b/libunwindstack/tests/MapsTest.cpp
@@ -61,6 +61,26 @@
ASSERT_EQ(0U, info->load_bias.load());
}
+TEST(MapsTest, map_move) {
+ Maps maps;
+
+ maps.Add(0x1000, 0x2000, 0, PROT_READ, "fake_map", 0);
+ maps.Add(0x3000, 0x4000, 0x10, 0, "", 0x1234);
+ maps.Add(0x5000, 0x6000, 1, 2, "fake_map2", static_cast<uint64_t>(-1));
+
+ Maps maps2 = std::move(maps);
+
+ ASSERT_EQ(3U, maps2.Total());
+ MapInfo* info = maps2.Get(0);
+ ASSERT_EQ(0x1000U, info->start);
+ ASSERT_EQ(0x2000U, info->end);
+ ASSERT_EQ(0U, info->offset);
+ ASSERT_EQ(PROT_READ, info->flags);
+ ASSERT_EQ("fake_map", info->name);
+ ASSERT_EQ(0U, info->elf_offset);
+ ASSERT_EQ(0U, info->load_bias.load());
+}
+
TEST(MapsTest, verify_parse_line) {
MapInfo info(nullptr, 0, 0, 0, 0, "");
diff --git a/libunwindstack/tests/UnwinderTest.cpp b/libunwindstack/tests/UnwinderTest.cpp
index d88531f..2dc5118 100644
--- a/libunwindstack/tests/UnwinderTest.cpp
+++ b/libunwindstack/tests/UnwinderTest.cpp
@@ -49,7 +49,7 @@
std::string str_name(name);
maps_->Add(start, end, offset, flags, name, static_cast<uint64_t>(-1));
if (elf != nullptr) {
- MapInfo* map_info = *--maps_->end();
+ const auto& map_info = *--maps_->end();
map_info->elf.reset(elf);
}
}
@@ -85,7 +85,7 @@
AddMapInfo(0x53000, 0x54000, 0, PROT_READ | PROT_WRITE, "/fake/fake.oat");
AddMapInfo(0xa3000, 0xa4000, 0, PROT_READ | PROT_WRITE | PROT_EXEC, "/fake/fake.vdex");
- MapInfo* info = *--maps_->end();
+ const auto& info = *--maps_->end();
info->load_bias = 0;
elf = new ElfFake(new MemoryFake);
@@ -98,8 +98,8 @@
elf->FakeSetInterface(new ElfInterfaceFake(nullptr));
AddMapInfo(0xa7000, 0xa8000, 0, PROT_READ | PROT_WRITE | PROT_EXEC, "/fake/fake_offset.oat",
elf);
- info = *--maps_->end();
- info->elf_offset = 0x8000;
+ const auto& info2 = *--maps_->end();
+ info2->elf_offset = 0x8000;
process_memory_.reset(new MemoryFake);
}