mgorny updated this revision to Diff 331688.
mgorny added a comment.
Actually wait for two signals. Store the extra info on parent signal, and use
it when handling the fork. For now, the handler just detaches the child and
resumes the parent.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D98822/new/
https://reviews.llvm.org/D98822
Files:
lldb/include/lldb/Host/common/NativeProcessProtocol.h
lldb/include/lldb/Host/linux/Host.h
lldb/packages/Python/lldbsuite/test/tools/lldb-server/gdbremote_testcase.py
lldb/source/Host/linux/Host.cpp
lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
lldb/source/Plugins/Process/Linux/NativeProcessLinux.h
lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.h
lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.h
Index: lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.h
===================================================================
--- lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.h
+++ lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.h
@@ -201,6 +201,8 @@
PacketResult Handle_g(StringExtractorGDBRemote &packet);
+ PacketResult Handle_qSupported_LLGS(StringExtractorGDBRemote &packet);
+
void SetCurrentThreadID(lldb::tid_t tid);
lldb::tid_t GetCurrentThreadID() const;
@@ -255,6 +257,9 @@
bool allow_any = false,
bool allow_all = false);
+ // Call SetEnabledExtensions() with appropriate flags on the process.
+ void SetEnabledExtensions(NativeProcessProtocol& process);
+
// For GDBRemoteCommunicationServerLLGS only
GDBRemoteCommunicationServerLLGS(const GDBRemoteCommunicationServerLLGS &) =
delete;
Index: lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
===================================================================
--- lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
+++ lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
@@ -184,6 +184,9 @@
RegisterMemberFunctionHandler(
StringExtractorGDBRemote::eServerPacketType_QPassSignals,
&GDBRemoteCommunicationServerLLGS::Handle_QPassSignals);
+ RegisterMemberFunctionHandler(
+ StringExtractorGDBRemote::eServerPacketType_qSupported,
+ &GDBRemoteCommunicationServerLLGS::Handle_qSupported_LLGS);
RegisterMemberFunctionHandler(
StringExtractorGDBRemote::eServerPacketType_jTraceStart,
@@ -254,6 +257,8 @@
m_debugged_process_up = std::move(*process_or);
}
+ SetEnabledExtensions(*m_debugged_process_up);
+
// Handle mirroring of inferior stdout/stderr over the gdb-remote protocol as
// needed. llgs local-process debugging may specify PTY paths, which will
// make these file actions non-null process launch -i/e/o will also make
@@ -321,6 +326,7 @@
return status;
}
m_debugged_process_up = std::move(*process_or);
+ SetEnabledExtensions(*m_debugged_process_up);
// Setup stdout/stderr mapping from inferior.
auto terminal_fd = m_debugged_process_up->GetTerminalFileDescriptor();
@@ -3703,3 +3709,28 @@
return tid;
}
+
+GDBRemoteCommunication::PacketResult
+GDBRemoteCommunicationServerLLGS::Handle_qSupported_LLGS(
+ StringExtractorGDBRemote &packet) {
+ auto ret = Handle_qSupported(packet);
+ if (m_debugged_process_up)
+ SetEnabledExtensions(*m_debugged_process_up);
+ return ret;
+}
+
+void GDBRemoteCommunicationServerLLGS::SetEnabledExtensions(
+ NativeProcessProtocol &process) {
+ Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_PROCESS));
+
+ uint32_t flags = 0;
+ if (m_fork_events_supported)
+ flags |= NativeProcessProtocol::Extension::fork;
+ if (m_vfork_events_supported)
+ flags |= NativeProcessProtocol::Extension::vfork;
+
+ llvm::Error error = process.SetEnabledExtensions(flags);
+ if (error)
+ LLDB_LOG_ERROR(log, std::move(error),
+ "Enabling protocol extensions failed: {0}");
+}
Index: lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.h
===================================================================
--- lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.h
+++ lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.h
@@ -38,6 +38,8 @@
uint32_t m_proc_infos_index;
bool m_thread_suffix_supported;
bool m_list_threads_in_stop_reply;
+ bool m_fork_events_supported;
+ bool m_vfork_events_supported;
PacketResult Handle_A(StringExtractorGDBRemote &packet);
Index: lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
===================================================================
--- lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
+++ lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
@@ -61,7 +61,8 @@
: GDBRemoteCommunicationServer(comm_name, listener_name),
m_process_launch_info(), m_process_launch_error(), m_proc_infos(),
m_proc_infos_index(0), m_thread_suffix_supported(false),
- m_list_threads_in_stop_reply(false) {
+ m_list_threads_in_stop_reply(false), m_fork_events_supported(false),
+ m_vfork_events_supported(false) {
RegisterMemberFunctionHandler(StringExtractorGDBRemote::eServerPacketType_A,
&GDBRemoteCommunicationServerCommon::Handle_A);
RegisterMemberFunctionHandler(
@@ -849,6 +850,19 @@
response.PutCString(";qXfer:libraries-svr4:read+");
#endif
response.PutCString(";multiprocess+");
+ response.PutCString(";fork-events+");
+ response.PutCString(";vfork-events+");
+
+ // Parse client-indicated features.
+ llvm::StringRef view = packet.GetStringRef();
+ llvm::SmallVector<llvm::StringRef, 4> client_features;
+ view.split(client_features, ';');
+ for (const auto &x : client_features) {
+ if (x == "fork-events+")
+ m_fork_events_supported = true;
+ else if (x == "vfork-events+")
+ m_vfork_events_supported = true;
+ }
return SendPacketNoLock(response.GetString());
}
Index: lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
===================================================================
--- lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
+++ lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
@@ -559,6 +559,8 @@
LazyBool m_supports_QPassSignals;
LazyBool m_supports_error_string_reply;
LazyBool m_supports_multiprocess;
+ LazyBool m_supports_fork_events;
+ LazyBool m_supports_vfork_events;
bool m_supports_qProcessInfoPID : 1, m_supports_qfProcessInfo : 1,
m_supports_qUserName : 1, m_supports_qGroupName : 1,
Index: lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
===================================================================
--- lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
+++ lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
@@ -90,6 +90,8 @@
m_supports_QPassSignals(eLazyBoolCalculate),
m_supports_error_string_reply(eLazyBoolCalculate),
m_supports_multiprocess(eLazyBoolCalculate),
+ m_supports_fork_events(eLazyBoolCalculate),
+ m_supports_vfork_events(eLazyBoolCalculate),
m_supports_qProcessInfoPID(true), m_supports_qfProcessInfo(true),
m_supports_qUserName(true), m_supports_qGroupName(true),
m_supports_qThreadStopInfo(true), m_supports_z0(true),
@@ -294,6 +296,8 @@
m_attach_or_wait_reply = eLazyBoolCalculate;
m_avoid_g_packets = eLazyBoolCalculate;
m_supports_multiprocess = eLazyBoolCalculate;
+ m_supports_fork_events = eLazyBoolCalculate;
+ m_supports_vfork_events = eLazyBoolCalculate;
m_supports_qXfer_auxv_read = eLazyBoolCalculate;
m_supports_qXfer_libraries_read = eLazyBoolCalculate;
m_supports_qXfer_libraries_svr4_read = eLazyBoolCalculate;
@@ -345,12 +349,16 @@
m_supports_qXfer_features_read = eLazyBoolNo;
m_supports_qXfer_memory_map_read = eLazyBoolNo;
m_supports_multiprocess = eLazyBoolNo;
+ m_supports_fork_events = eLazyBoolNo;
+ m_supports_vfork_events = eLazyBoolNo;
m_max_packet_size = UINT64_MAX; // It's supposed to always be there, but if
// not, we assume no limit
// build the qSupported packet
std::vector<std::string> features = {"xmlRegisters=i386,arm,mips,arc",
- "multiprocess+"};
+ "multiprocess+",
+ "fork-events+",
+ "vfork-events+"};
StreamString packet;
packet.PutCString("qSupported");
for (uint32_t i = 0; i < features.size(); ++i) {
@@ -442,6 +450,16 @@
else
m_supports_multiprocess = eLazyBoolNo;
+ if (::strstr(response_cstr, "fork-events+"))
+ m_supports_fork_events = eLazyBoolYes;
+ else
+ m_supports_fork_events = eLazyBoolNo;
+
+ if (::strstr(response_cstr, "vfork-events+"))
+ m_supports_vfork_events = eLazyBoolYes;
+ else
+ m_supports_vfork_events = eLazyBoolNo;
+
const char *packet_size_str = ::strstr(response_cstr, "PacketSize=");
if (packet_size_str) {
StringExtractorGDBRemote packet_response(packet_size_str +
Index: lldb/source/Plugins/Process/Linux/NativeProcessLinux.h
===================================================================
--- lldb/source/Plugins/Process/Linux/NativeProcessLinux.h
+++ lldb/source/Plugins/Process/Linux/NativeProcessLinux.h
@@ -128,6 +128,8 @@
bool SupportHardwareSingleStepping() const;
+ llvm::Error SetEnabledExtensions(uint32_t flags) override;
+
protected:
llvm::Expected<llvm::ArrayRef<uint8_t>>
GetSoftwareBreakpointTrapOpcode(size_t size_hint) override;
@@ -146,6 +148,8 @@
/// Inferior memory (allocated by us) and its size.
llvm::DenseMap<lldb::addr_t, lldb::addr_t> m_allocated_memory;
+ uint32_t m_enabled_extensions;
+
// Private Instance Methods
NativeProcessLinux(::pid_t pid, int terminal_fd, NativeDelegate &delegate,
const ArchSpec &arch, MainLoop &mainloop,
@@ -154,7 +158,7 @@
// Returns a list of process threads that we have attached to.
static llvm::Expected<std::vector<::pid_t>> Attach(::pid_t pid);
- static Status SetDefaultPtraceOpts(const lldb::pid_t);
+ static Status SetPtraceOpts(const lldb::pid_t, uint32_t extensions = 0);
void MonitorCallback(lldb::pid_t pid, bool exited, WaitStatus status);
@@ -248,6 +252,19 @@
lldb::user_id_t m_pt_proces_trace_id = LLDB_INVALID_UID;
TraceOptions m_pt_process_trace_config;
+
+ struct ForkInfo {
+ uint32_t event;
+ lldb::tid_t parent_tid;
+ };
+
+ // Map of child processes that have been signaled once, and we are
+ // waiting for the second signal.
+ llvm::DenseMap<lldb::pid_t, llvm::Optional<ForkInfo>> m_pending_process_map;
+
+ // Handle a fork-like event. If received by parent, fork_info contains
+ // additional info.
+ void MonitorFork(lldb::pid_t child_pid, llvm::Optional<ForkInfo> fork_info);
};
} // namespace process_linux
Index: lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
===================================================================
--- lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
+++ lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
@@ -30,6 +30,7 @@
#include "lldb/Host/PseudoTerminal.h"
#include "lldb/Host/ThreadLauncher.h"
#include "lldb/Host/common/NativeRegisterContext.h"
+#include "lldb/Host/linux/Host.h"
#include "lldb/Host/linux/Ptrace.h"
#include "lldb/Host/linux/Uio.h"
#include "lldb/Host/posix/ProcessLauncherPosixFork.h"
@@ -247,7 +248,7 @@
LLDB_LOG(log, "pid = {0:x}, detected architecture {1}", pid,
Info.GetArchitecture().GetArchitectureName());
- status = SetDefaultPtraceOpts(pid);
+ status = SetPtraceOpts(pid);
if (status.Fail()) {
LLDB_LOG(log, "failed to set default ptrace options: {0}", status);
return status.ToError();
@@ -286,7 +287,8 @@
NativeDelegate &delegate,
const ArchSpec &arch, MainLoop &mainloop,
llvm::ArrayRef<::pid_t> tids)
- : NativeProcessELF(pid, terminal_fd, delegate), m_arch(arch) {
+ : NativeProcessELF(pid, terminal_fd, delegate), m_arch(arch),
+ m_enabled_extensions(0) {
if (m_terminal_fd != -1) {
Status status = EnsureFDFlags(m_terminal_fd, O_NONBLOCK);
assert(status.Success());
@@ -351,7 +353,7 @@
std::error_code(errno, std::generic_category()));
}
- if ((status = SetDefaultPtraceOpts(tid)).Fail())
+ if ((status = SetPtraceOpts(tid)).Fail())
return status.ToError();
LLDB_LOG(log, "adding tid = {0}", tid);
@@ -375,7 +377,8 @@
return std::move(tids);
}
-Status NativeProcessLinux::SetDefaultPtraceOpts(lldb::pid_t pid) {
+Status NativeProcessLinux::SetPtraceOpts(lldb::pid_t pid,
+ uint32_t extensions) {
long ptrace_opts = 0;
// Have the child raise an event on exit. This is used to keep the child in
@@ -383,14 +386,17 @@
ptrace_opts |= PTRACE_O_TRACEEXIT;
// Have the tracer trace threads which spawn in the inferior process.
- // TODO: if we want to support tracing the inferiors' child, add the
- // appropriate ptrace flags here (PTRACE_O_TRACEFORK, PTRACE_O_TRACEVFORK)
ptrace_opts |= PTRACE_O_TRACECLONE;
// Have the tracer notify us before execve returns (needed to disable legacy
// SIGTRAP generation)
ptrace_opts |= PTRACE_O_TRACEEXEC;
+ // Have the tracer trace forked children if the fork-events extension
+ // is supported.
+ if (extensions & Extension::fork)
+ ptrace_opts |= PTRACE_O_TRACEFORK;
+
return PtraceWrapper(PTRACE_SETOPTIONS, pid, nullptr, (void *)ptrace_opts);
}
@@ -444,6 +450,14 @@
LLDB_LOG(log, "tid {0}, si_code: {1}, si_pid: {2}", pid, info.si_code,
info.si_pid);
+ llvm::Optional<lldb::pid_t> tgid = getPIDForTID(pid);
+ if (tgid && tgid.getValue() != GetID()) {
+ LLDB_LOG(log, "tid {0} belongs to a different tgid {1}, assuming child",
+ pid, tgid.getValue());
+ MonitorFork(pid, llvm::None);
+ return;
+ }
+
NativeThreadLinux &thread = AddThread(pid);
// Resume the newly created thread.
@@ -649,6 +663,14 @@
break;
}
+ case (SIGTRAP | (PTRACE_EVENT_FORK << 8)): {
+ unsigned long data = 0;
+ if (GetEventMessage(thread.GetID(), &data).Fail())
+ data = 0;
+
+ MonitorFork(data, {{PTRACE_EVENT_FORK, thread.GetID()}});
+ break;
+ }
case 0:
case TRAP_TRACE: // We receive this on single stepping.
case TRAP_HWBKPT: // We receive this on watchpoint hit
@@ -858,6 +880,40 @@
StopRunningThreads(thread.GetID());
}
+void NativeProcessLinux::MonitorFork(
+ lldb::pid_t child_pid,
+ llvm::Optional<NativeProcessLinux::ForkInfo> fork_info) {
+ Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
+ LLDB_LOG(log, "fork, child_pid={0}, fork info?={1}", child_pid,
+ fork_info.hasValue());
+
+ auto find_it = m_pending_process_map.find(child_pid);
+ if (find_it == m_pending_process_map.end()) {
+ // not in the map, so this is the first signal for the PID
+ m_pending_process_map.insert({child_pid, fork_info});
+ return;
+ }
+
+ // second signal for the pid
+ assert(fork_info.hasValue() != find_it->second.hasValue());
+ if (!fork_info) {
+ // child signal does not indicate the event, so grab the one stored
+ // earlier
+ fork_info = find_it->second;
+ }
+
+ LLDB_LOG(log, "second signal for child_pid={0}, parent_tid={1}, event={2}",
+ child_pid, fork_info->parent_tid, fork_info->event);
+
+ m_pending_process_map.erase(child_pid);
+
+ // for now, just detach the child and resume the parent
+ Detach(child_pid);
+ auto thread = GetThreadByID(fork_info->parent_tid);
+ if (thread)
+ ResumeThread(*thread, thread->GetState(), LLDB_INVALID_SIGNAL_NUMBER);
+}
+
bool NativeProcessLinux::SupportHardwareSingleStepping() const {
if (m_arch.GetMachine() == llvm::Triple::arm || m_arch.IsMIPS())
return false;
@@ -2021,3 +2077,16 @@
return error;
}
+
+llvm::Error NativeProcessLinux::SetEnabledExtensions(uint32_t flags) {
+ m_enabled_extensions = flags;
+ for (const auto &thread : m_threads) {
+ assert(thread && "thread list should not contain NULL threads");
+
+ Status status = SetPtraceOpts(thread->GetID(), flags);
+ if (status.Fail())
+ return status.ToError();
+ }
+
+ return llvm::Error::success();
+}
Index: lldb/source/Host/linux/Host.cpp
===================================================================
--- lldb/source/Host/linux/Host.cpp
+++ lldb/source/Host/linux/Host.cpp
@@ -53,7 +53,8 @@
}
static bool GetStatusInfo(::pid_t Pid, ProcessInstanceInfo &ProcessInfo,
- ProcessState &State, ::pid_t &TracerPid) {
+ ProcessState &State, ::pid_t &TracerPid,
+ ::pid_t &Tgid) {
Log *log = GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST);
auto BufferOrError = getProcFile(Pid, "status");
@@ -107,6 +108,9 @@
} else if (Line.consume_front("TracerPid:")) {
Line = Line.ltrim();
Line.consumeInteger(10, TracerPid);
+ } else if (Line.consume_front("Tgid:")) {
+ Line = Line.ltrim();
+ Line.consumeInteger(10, Tgid);
}
}
return true;
@@ -204,6 +208,7 @@
static bool GetProcessAndStatInfo(::pid_t pid,
ProcessInstanceInfo &process_info,
ProcessState &State, ::pid_t &tracerpid) {
+ ::pid_t tgid;
tracerpid = 0;
process_info.Clear();
@@ -214,7 +219,7 @@
GetProcessEnviron(pid, process_info);
// Get User and Group IDs and get tracer pid.
- if (!GetStatusInfo(pid, process_info, State, tracerpid))
+ if (!GetStatusInfo(pid, process_info, State, tracerpid, tgid))
return false;
return true;
@@ -308,3 +313,15 @@
Status Host::ShellExpandArguments(ProcessLaunchInfo &launch_info) {
return Status("unimplemented");
}
+
+namespace lldb_private {
+llvm::Optional<::pid_t> getPIDForTID(::pid_t tid) {
+ ::pid_t tracerpid, tgid = LLDB_INVALID_PROCESS_ID;
+ ProcessInstanceInfo process_info;
+ ProcessState state;
+
+ if (!GetStatusInfo(tid, process_info, state, tracerpid, tgid) || tgid == 0)
+ return llvm::None;
+ return tgid;
+}
+}
Index: lldb/packages/Python/lldbsuite/test/tools/lldb-server/gdbremote_testcase.py
===================================================================
--- lldb/packages/Python/lldbsuite/test/tools/lldb-server/gdbremote_testcase.py
+++ lldb/packages/Python/lldbsuite/test/tools/lldb-server/gdbremote_testcase.py
@@ -904,6 +904,8 @@
"qEcho",
"QPassSignals",
"multiprocess",
+ "fork-events",
+ "vfork-events",
]
def parse_qSupported_response(self, context):
Index: lldb/include/lldb/Host/linux/Host.h
===================================================================
--- /dev/null
+++ lldb/include/lldb/Host/linux/Host.h
@@ -0,0 +1,21 @@
+//===-- Host.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 LLDB_HOST_LINUX_HOST_H
+#define LLDB_HOST_LINUX_HOST_H
+
+#include "llvm/ADT/Optional.h"
+
+namespace lldb_private {
+
+// Get PID (i.e. the primary thread ID) corresponding to the specified TID.
+llvm::Optional<lldb::pid_t> getPIDForTID(::pid_t tid);
+
+} // namespace lldb_private
+
+#endif // #ifndef LLDB_HOST_LINUX_HOST_H
Index: lldb/include/lldb/Host/common/NativeProcessProtocol.h
===================================================================
--- lldb/include/lldb/Host/common/NativeProcessProtocol.h
+++ lldb/include/lldb/Host/common/NativeProcessProtocol.h
@@ -397,6 +397,24 @@
return llvm::make_error<UnimplementedError>();
}
+ /// Extension flag constants, passed to SetEnabledExtension().
+ struct Extension {
+ static constexpr uint32_t fork = 1;
+ static constexpr uint32_t vfork = 2;
+ };
+
+ /// Method called in order to propagate the bitmap of protocol
+ /// extensions supported by the client.
+ ///
+ /// \param[in] flags
+ /// The bitmap of enabled extensions.
+ ///
+ /// \return An error if extension-related setup failed, success
+ /// otherwise.
+ virtual llvm::Error SetEnabledExtensions(uint32_t flags) {
+ return llvm::Error::success();
+ }
+
protected:
struct SoftwareBreakpoint {
uint32_t ref_count;
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