[lldb][AIX] get host info for AIX (cont..) (llvm#138687)

This PR is in reference to porting LLDB on AIX.

Link to discussions on llvm discourse and github:

1. https://discourse.llvm.org/t/port-lldb-to-ibm-aix/80640
2. llvm#101657
The complete changes for porting are present in this draft PR:
llvm#102601

- Added testcase for `GetProgramFileSpec()` & `FindProcesses()`
- Added changes to get the host information for AIX (info like
FindProcessesImpl() GetProgramFileSpec()),
continue from the PR llvm#134354

Author: HemangGadhavi

lldb/source/Host/aix/Host.cpp

@@ -13,6 +13,7 @@
 #include "lldb/Utility/ProcessInfo.h"
 #include "lldb/Utility/Status.h"
 #include "llvm/BinaryFormat/XCOFF.h"
+#include <dirent.h>
 #include <sys/proc.h>
 #include <sys/procfs.h>
 
@@ -133,7 +134,44 @@ static bool GetProcessAndStatInfo(::pid_t pid,
 
 uint32_t Host::FindProcessesImpl(const ProcessInstanceInfoMatch &match_info,
                                  ProcessInstanceInfoList &process_infos) {
-  return 0;
+  static const char procdir[] = "/proc/";
+
+  DIR *dirproc = opendir(procdir);
+  if (dirproc) {
+    struct dirent *direntry = nullptr;
+    const uid_t our_uid = getuid();
+    const lldb::pid_t our_pid = getpid();
+    bool all_users = match_info.GetMatchAllUsers();
+
+    while ((direntry = readdir(dirproc)) != nullptr) {
+      lldb::pid_t pid;
+      // Skip non-numeric name directories
+      if (!llvm::to_integer(direntry->d_name, pid))
+        continue;
+      // Skip this process.
+      if (pid == our_pid)
+        continue;
+
+      ProcessState State;
+      ProcessInstanceInfo process_info;
+      if (!GetProcessAndStatInfo(pid, process_info, State))
+        continue;
+
+      if (State == ProcessState::Zombie ||
+          State == ProcessState::TracedOrStopped)
+        continue;
+
+      // Check for user match if we're not matching all users and not running
+      // as root.
+      if (!all_users && (our_uid != 0) && (process_info.GetUserID() != our_uid))
+        continue;
+
+      if (match_info.Matches(process_info))
+        process_infos.push_back(process_info);
+    }
+    closedir(dirproc);
+  }
+  return process_infos.size();
 }
 
 bool Host::GetProcessInfo(lldb::pid_t pid, ProcessInstanceInfo &process_info) {

lldb/source/Host/aix/HostInfoAIX.cpp

@@ -7,6 +7,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "lldb/Host/aix/HostInfoAIX.h"
+#include "lldb/Host/posix/Support.h"
+#include <sys/procfs.h>
 
 using namespace lldb_private;
 
@@ -18,5 +20,17 @@ void HostInfoAIX::Terminate() { HostInfoBase::Terminate(); }
 
 FileSpec HostInfoAIX::GetProgramFileSpec() {
   static FileSpec g_program_filespec;
+  struct psinfo psinfoData;
+  auto BufferOrError = getProcFile(getpid(), "psinfo");
+  if (BufferOrError) {
+    std::unique_ptr<llvm::MemoryBuffer> PsinfoBuffer =
+        std::move(*BufferOrError);
+    memcpy(&psinfoData, PsinfoBuffer->getBufferStart(), sizeof(psinfoData));
+    llvm::StringRef exe_path(
+        psinfoData.pr_psargs,
+        strnlen(psinfoData.pr_psargs, sizeof(psinfoData.pr_psargs)));
+    if (!exe_path.empty())
+      g_program_filespec.SetFile(exe_path, FileSpec::Style::native);
+  }
   return g_program_filespec;
 }

lldb/unittests/Host/HostInfoTest.cpp

@@ -54,6 +54,11 @@ TEST_F(HostInfoTest, GetHostname) {
   EXPECT_TRUE(HostInfo::GetHostname(s));
 }
 
+TEST_F(HostInfoTest, GetProgramFileSpec) {
+  FileSpec filespec = HostInfo::GetProgramFileSpec();
+  EXPECT_TRUE(FileSystem::Instance().Exists(filespec));
+}
+
 #if defined(__APPLE__)
 TEST_F(HostInfoTest, GetXcodeSDK) {
   auto get_sdk = [](std::string sdk, bool error = false) -> llvm::StringRef {

lldb/unittests/Host/HostTest.cpp

@@ -9,15 +9,18 @@
 #include "lldb/Host/Host.h"
 #include "TestingSupport/SubsystemRAII.h"
 #include "lldb/Host/FileSystem.h"
+#include "lldb/Host/HostInfo.h"
 #include "lldb/Host/Pipe.h"
 #include "lldb/Host/ProcessLaunchInfo.h"
 #include "lldb/Utility/ProcessInfo.h"
+#include "llvm/ADT/ScopeExit.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Testing/Support/Error.h"
 #include "gtest/gtest.h"
 #include <future>
+#include <thread>
 
 using namespace lldb_private;
 using namespace llvm;
@@ -90,6 +93,44 @@ TEST(Host, LaunchProcessSetsArgv0) {
   ASSERT_THAT(exit_status.get_future().get(), 0);
 }
 
+TEST(Host, FindProcesses) {
+  SubsystemRAII<FileSystem, HostInfo> subsystems;
+
+  if (test_arg != 0) {
+    // Give the parent time to retrieve information about self.
+    // It will kill self when it is done.
+    std::this_thread::sleep_for(std::chrono::seconds(10));
+    exit(0);
+  }
+
+  bool foundPID = false;
+  ProcessLaunchInfo info;
+  ProcessInstanceInfoList processes;
+  ProcessInstanceInfoMatch match(TestMainArgv0, NameMatch::Equals);
+  info.SetExecutableFile(FileSpec(TestMainArgv0),
+                         /*add_exe_file_as_first_arg=*/true);
+  info.GetArguments().AppendArgument("--gtest_filter=Host.FindProcesses");
+  info.GetArguments().AppendArgument("--test-arg=48");
+  std::promise<int> exit_status;
+  info.SetMonitorProcessCallback([&](lldb::pid_t pid, int signal, int status) {
+    exit_status.set_value(status);
+  });
+  ASSERT_THAT_ERROR(Host::LaunchProcess(info).takeError(), Succeeded());
+  ASSERT_TRUE(Host::FindProcesses(match, processes));
+  for (const auto &process : processes) {
+    if (process.GetProcessID() == info.GetProcessID()) {
+      ASSERT_EQ(process.GetExecutableFile().GetFilename(),
+                info.GetExecutableFile().GetFilename());
+      foundPID = true;
+    }
+  }
+  ASSERT_TRUE(foundPID);
+  auto clean_up = llvm::make_scope_exit([&] {
+    Host::Kill(info.GetProcessID(), SIGKILL);
+    exit_status.get_future().get();
+  });
+}
+
 TEST(Host, LaunchProcessDuplicatesHandle) {
   static constexpr llvm::StringLiteral test_msg("Hello subprocess!");