[Lldb-commits] [lldb] [lldb][AIX] Added base files for NativeProcess Support for AIX (PR #118160)

[David Spickett via lldb-commits]

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@@ -0,0 +1,256 @@
+//===-- NativeProcessAIX.cpp --------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "NativeProcessAIX.h"
+#include "Plugins/Process/POSIX/ProcessPOSIXLog.h"
+#include "lldb/Host/Host.h"
+#include "lldb/Host/HostProcess.h"
+#include "lldb/Host/ProcessLaunchInfo.h"
+#include "lldb/Host/posix/ProcessLauncherPosixFork.h"
+#include "lldb/Symbol/ObjectFile.h"
+#include "lldb/Utility/Log.h"
+#include "lldb/Utility/State.h"
+#include "lldb/Utility/Status.h"
+#include "llvm/Support/Errno.h"
+#include "llvm/Support/Error.h"
+#include <cerrno>
+#include <cstdint>
+#include <cstring>
+#include <sstream>
+#include <string>
+#include <sys/ptrace.h>
+#include <unistd.h>
+
+using namespace lldb;
+using namespace lldb_private;
+using namespace lldb_private::process_aix;
+using namespace llvm;
+
+static constexpr unsigned k_ptrace_word_size = sizeof(void *);
+static_assert(sizeof(long) >= k_ptrace_word_size,
+              "Size of long must be larger than ptrace word size");
+
+// Simple helper function to ensure flags are enabled on the given file
+// descriptor.
+static llvm::Error EnsureFDFlags(int fd, int flags) {
+  int status = fcntl(fd, F_GETFL);
+  if (status == -1)
+    return errorCodeToError(errnoAsErrorCode());
+  if (fcntl(fd, F_SETFL, status | flags) == -1)
+    return errorCodeToError(errnoAsErrorCode());
+  return Error::success();
+}
+
+NativeProcessAIX::Manager::Manager(MainLoop &mainloop)
+    : NativeProcessProtocol::Manager(mainloop) {
+  Status status;
+  m_sigchld_handle = mainloop.RegisterSignal(
+      SIGCHLD, [this](MainLoopBase &) { SigchldHandler(); }, status);
+  assert(m_sigchld_handle && status.Success());
+}
+
+// Public Static Methods
+
+llvm::Expected<std::unique_ptr<NativeProcessProtocol>>
+NativeProcessAIX::Manager::Launch(ProcessLaunchInfo &launch_info,
+                                  NativeDelegate &native_delegate) {
+  Log *log = GetLog(POSIXLog::Process);
+
+  Status status;
+  ::pid_t pid = ProcessLauncherPosixFork()
+                    .LaunchProcess(launch_info, status)
+                    .GetProcessId();
+  LLDB_LOG(log, "pid = {0:x}", pid);
+  if (status.Fail()) {
+    LLDB_LOG(log, "failed to launch process: {0}", status);
+    return status.ToError();
+  }
+
+  // Wait for the child process to trap on its call to execve.
+  int wstatus = 0;
+  ::pid_t wpid = llvm::sys::RetryAfterSignal(-1, ::waitpid, pid, &wstatus, 0);
+  assert(wpid == pid);
+  UNUSED_IF_ASSERT_DISABLED(wpid);
+  if (!WIFSTOPPED(wstatus)) {
+    LLDB_LOG(log, "Could not sync with inferior process: wstatus={1}",
+             WaitStatus::Decode(wstatus));
+    return llvm::make_error<StringError>("Could not sync with inferior process",
+                                         llvm::inconvertibleErrorCode());
+  }
+  LLDB_LOG(log, "inferior started, now in stopped state");
+
+  ProcessInstanceInfo Info;
+  if (!Host::GetProcessInfo(pid, Info)) {
+    return llvm::make_error<StringError>("Cannot get process architectrue",
+                                         llvm::inconvertibleErrorCode());
+  }
+
+  // Set the architecture to the exe architecture.
+  LLDB_LOG(log, "pid = {0}, detected architecture {1}", pid,
+           Info.GetArchitecture().GetArchitectureName());
+
+  return std::unique_ptr<NativeProcessAIX>(new NativeProcessAIX(
+      pid, launch_info.GetPTY().ReleasePrimaryFileDescriptor(), native_delegate,
+      Info.GetArchitecture(), *this, {pid}));
+}
+
+llvm::Expected<std::unique_ptr<NativeProcessProtocol>>
+NativeProcessAIX::Manager::Attach(
+    lldb::pid_t pid, NativeProcessProtocol::NativeDelegate &native_delegate) {
+  Log *log = GetLog(POSIXLog::Process);
+  LLDB_LOG(log, "pid = {0:x}", pid);
+
+  ProcessInstanceInfo Info;
+  if (!Host::GetProcessInfo(pid, Info)) {
+    return llvm::make_error<StringError>("Cannot get process architectrue",
+                                         llvm::inconvertibleErrorCode());
+  }
+  auto tids_or = NativeProcessAIX::Attach(pid);
+  if (!tids_or)
+    return tids_or.takeError();
+
+  return std::unique_ptr<NativeProcessAIX>(new NativeProcessAIX(
+      pid, -1, native_delegate, Info.GetArchitecture(), *this, *tids_or));
+}
+
+lldb::addr_t NativeProcessAIX::GetSharedLibraryInfoAddress() {
+  return LLDB_INVALID_ADDRESS;
+}
+
+NativeProcessAIX::Extension
+NativeProcessAIX::Manager::GetSupportedExtensions() const {
+  NativeProcessAIX::Extension supported = {};
+
+  return supported;
+}
+
+void NativeProcessAIX::Manager::SigchldHandler() {}
+
+void NativeProcessAIX::Manager::CollectThread(::pid_t tid) {}
+
+// Public Instance Methods
+
+NativeProcessAIX::NativeProcessAIX(::pid_t pid, int terminal_fd,
+                                   NativeDelegate &delegate,
+                                   const ArchSpec &arch, Manager &manager,
+                                   llvm::ArrayRef<::pid_t> tids)
+    : NativeProcessProtocol(pid, terminal_fd, delegate), m_manager(manager),
+      m_arch(arch) {
+  manager.AddProcess(*this);
+  if (m_terminal_fd != -1)
+    cantFail(EnsureFDFlags(m_terminal_fd, O_NONBLOCK));
----------------
DavidSpickett wrote:

First time seeing this `cantFail` usage. What's the effect of using it here?

Just looking at this line, it seems like you have EnsureFDFlags that can fail, but then wrap it in something that prevents it failing. Or is it just reporting if it does fail?

If it silences the failure, then I question what the utility of EnsureFDFlags is.

https://github.com/llvm/llvm-project/pull/118160