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// Copyright 2017 The Crashpad Authors
//
// 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 "snapshot/linux/debug_rendezvous.h"
#include <stdint.h>
#include <set>
#include "base/logging.h"
#include "build/build_config.h"
#if BUILDFLAG(IS_ANDROID)
#include <android/api-level.h>
#endif
namespace crashpad {
namespace {
struct Traits32 {
using Integer = int32_t;
using Address = uint32_t;
};
struct Traits64 {
using Integer = int64_t;
using Address = uint64_t;
};
template <typename Traits>
struct DebugRendezvousSpecific {
typename Traits::Integer r_version;
typename Traits::Address r_map;
typename Traits::Address r_brk;
typename Traits::Integer r_state;
typename Traits::Address r_ldbase;
};
template <typename Traits>
struct LinkEntrySpecific {
typename Traits::Address l_addr;
typename Traits::Address l_name;
typename Traits::Address l_ld;
typename Traits::Address l_next;
typename Traits::Address l_prev;
};
template <typename Traits>
bool ReadLinkEntry(const ProcessMemoryRange& memory,
LinuxVMAddress* address,
DebugRendezvous::LinkEntry* entry_out) {
LinkEntrySpecific<Traits> entry;
if (!memory.Read(*address, sizeof(entry), &entry)) {
return false;
}
std::string name;
if (!memory.ReadCStringSizeLimited(entry.l_name, 4096, &name)) {
name.clear();
}
entry_out->load_bias = entry.l_addr;
entry_out->dynamic_array = entry.l_ld;
entry_out->name.swap(name);
*address = entry.l_next;
return true;
}
} // namespace
DebugRendezvous::LinkEntry::LinkEntry()
: name(), load_bias(0), dynamic_array(0) {}
DebugRendezvous::DebugRendezvous()
: modules_(), executable_(), initialized_() {}
DebugRendezvous::~DebugRendezvous() {}
bool DebugRendezvous::Initialize(const ProcessMemoryRange& memory,
LinuxVMAddress address) {
INITIALIZATION_STATE_SET_INITIALIZING(initialized_);
if (!(memory.Is64Bit() ? InitializeSpecific<Traits64>(memory, address)
: InitializeSpecific<Traits32>(memory, address))) {
return false;
}
INITIALIZATION_STATE_SET_VALID(initialized_);
return true;
}
const DebugRendezvous::LinkEntry* DebugRendezvous::Executable() const {
INITIALIZATION_STATE_DCHECK_VALID(initialized_);
return &executable_;
}
const std::vector<DebugRendezvous::LinkEntry>& DebugRendezvous::Modules()
const {
INITIALIZATION_STATE_DCHECK_VALID(initialized_);
return modules_;
}
template <typename Traits>
bool DebugRendezvous::InitializeSpecific(const ProcessMemoryRange& memory,
LinuxVMAddress address) {
DebugRendezvousSpecific<Traits> debug;
if (!memory.Read(address, sizeof(debug), &debug)) {
return false;
}
if (debug.r_version != 1) {
LOG(ERROR) << "unexpected version " << debug.r_version;
return false;
}
LinuxVMAddress link_entry_address = debug.r_map;
if (!ReadLinkEntry<Traits>(memory, &link_entry_address, &executable_)) {
return false;
}
std::set<LinuxVMAddress> visited;
while (link_entry_address) {
if (!visited.insert(link_entry_address).second) {
LOG(ERROR) << "cycle at address 0x" << std::hex << link_entry_address;
return false;
}
LinkEntry entry;
if (!ReadLinkEntry<Traits>(memory, &link_entry_address, &entry)) {
return false;
}
modules_.push_back(entry);
}
#if BUILDFLAG(IS_ANDROID)
// Android P (API 28) mistakenly places the vdso in the first entry in the
// link map.
const int android_runtime_api = android_get_device_api_level();
if (android_runtime_api == 28 && executable_.name == "[vdso]") {
LinkEntry executable = modules_[0];
modules_[0] = executable_;
executable_ = executable;
}
#endif // BUILDFLAG(IS_ANDROID)
return true;
}
} // namespace crashpad