llvm-project/lldb/source/Plugins/Process/NetBSD/NativeProcessNetBSD.h
Pavel Labath 2c4226f8ac [lldb-server][linux] Add ability to allocate memory
This patch adds support for the _M and _m gdb-remote packets, which
(de)allocate memory in the inferior. This works by "injecting" a
m(un)map syscall into the inferior. This consists of:
- finding an executable page of memory
- writing the syscall opcode to it
- setting up registers according to the os syscall convention
- single stepping over the syscall

The advantage of this approach over calling the mmap function is that
this works even in case the mmap function is buggy or unavailable. The
disadvantage is it is more platform-dependent, which is why this patch
only works on X86 (_32 and _64) right now. Adding support for other
linux architectures should be easy and consist of defining the
appropriate syscall constants. Adding support for other OSes depends on
the its ability to do a similar trick.

Differential Revision: https://reviews.llvm.org/D89124
2020-10-14 15:02:09 +02:00

117 lines
3.8 KiB
C++

//===-- NativeProcessNetBSD.h --------------------------------- -*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef liblldb_NativeProcessNetBSD_H_
#define liblldb_NativeProcessNetBSD_H_
#include "Plugins/Process/POSIX/NativeProcessELF.h"
#include "lldb/Target/MemoryRegionInfo.h"
#include "lldb/Utility/ArchSpec.h"
#include "lldb/Utility/FileSpec.h"
#include "NativeThreadNetBSD.h"
namespace lldb_private {
namespace process_netbsd {
/// \class NativeProcessNetBSD
/// Manages communication with the inferior (debugee) process.
///
/// Upon construction, this class prepares and launches an inferior process
/// for debugging.
///
/// Changes in the inferior process state are broadcasted.
class NativeProcessNetBSD : public NativeProcessELF {
public:
class Factory : public NativeProcessProtocol::Factory {
public:
llvm::Expected<std::unique_ptr<NativeProcessProtocol>>
Launch(ProcessLaunchInfo &launch_info, NativeDelegate &native_delegate,
MainLoop &mainloop) const override;
llvm::Expected<std::unique_ptr<NativeProcessProtocol>>
Attach(lldb::pid_t pid, NativeDelegate &native_delegate,
MainLoop &mainloop) const override;
};
// NativeProcessProtocol Interface
Status Resume(const ResumeActionList &resume_actions) override;
Status Halt() override;
Status Detach() override;
Status Signal(int signo) override;
Status Interrupt() override;
Status Kill() override;
Status GetMemoryRegionInfo(lldb::addr_t load_addr,
MemoryRegionInfo &range_info) override;
Status ReadMemory(lldb::addr_t addr, void *buf, size_t size,
size_t &bytes_read) override;
Status WriteMemory(lldb::addr_t addr, const void *buf, size_t size,
size_t &bytes_written) override;
lldb::addr_t GetSharedLibraryInfoAddress() override;
size_t UpdateThreads() override;
const ArchSpec &GetArchitecture() const override { return m_arch; }
Status SetBreakpoint(lldb::addr_t addr, uint32_t size,
bool hardware) override;
Status GetLoadedModuleFileSpec(const char *module_path,
FileSpec &file_spec) override;
Status GetFileLoadAddress(const llvm::StringRef &file_name,
lldb::addr_t &load_addr) override;
llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
GetAuxvData() const override;
// Interface used by NativeRegisterContext-derived classes.
static Status PtraceWrapper(int req, lldb::pid_t pid, void *addr = nullptr,
int data = 0, int *result = nullptr);
private:
MainLoop::SignalHandleUP m_sigchld_handle;
ArchSpec m_arch;
LazyBool m_supports_mem_region = eLazyBoolCalculate;
std::vector<std::pair<MemoryRegionInfo, FileSpec>> m_mem_region_cache;
// Private Instance Methods
NativeProcessNetBSD(::pid_t pid, int terminal_fd, NativeDelegate &delegate,
const ArchSpec &arch, MainLoop &mainloop);
bool HasThreadNoLock(lldb::tid_t thread_id);
NativeThreadNetBSD &AddThread(lldb::tid_t thread_id);
void RemoveThread(lldb::tid_t thread_id);
void MonitorCallback(lldb::pid_t pid, int signal);
void MonitorExited(lldb::pid_t pid, WaitStatus status);
void MonitorSIGSTOP(lldb::pid_t pid);
void MonitorSIGTRAP(lldb::pid_t pid);
void MonitorSignal(lldb::pid_t pid, int signal);
Status PopulateMemoryRegionCache();
void SigchldHandler();
Status Attach();
Status ReinitializeThreads();
};
} // namespace process_netbsd
} // namespace lldb_private
#endif // #ifndef liblldb_NativeProcessNetBSD_H_