From d1db1c791195f3c0cf148e2be8bd46c5a51ca535 Mon Sep 17 00:00:00 2001
From: Palo Kisa <palo.kisa@gmail.com>
Date: Tue, 7 Mar 2023 14:21:40 +0100
Subject: [PATCH 978/978] reaper: Build/Run on systems with procps-ng >= 4.0.0
 (#456)

On Linux, make it possible to use libproc2 or libprocps whichever is
available.
---
 CMakeLists.txt                  |  6 +++++-
 lxqt-session/src/procreaper.cpp | 24 +++++++++++++++++++++++-
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index a3c5e0d..f208600 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -35,7 +35,11 @@ find_package(X11 REQUIRED)
 message(STATUS "Building with Qt${Qt5Core_VERSION}")
 find_package(PkgConfig REQUIRED)
 if (CMAKE_SYSTEM_NAME STREQUAL "Linux")
-    pkg_search_module(PROCPS REQUIRED libprocps)
+    pkg_search_module(PROCPS REQUIRED libproc2 libprocps)
+    message(STATUS "Using PROCPS -> ${PROCPS_MODULE_NAME} v${PROCPS_VERSION}")
+    if (PROCPS_VERSION VERSION_GREATER_EQUAL 4.0.0)
+        add_definitions("-DUSING_LIBPROC2")
+    endif()
 endif()
 
 # Please don't move, must be after lxqt
diff --git a/lxqt-session/src/procreaper.cpp b/lxqt-session/src/procreaper.cpp
index 2acd030..1ea4bdc 100644
--- a/lxqt-session/src/procreaper.cpp
+++ b/lxqt-session/src/procreaper.cpp
@@ -29,7 +29,11 @@
 #include "log.h"
 #if defined(Q_OS_LINUX)
 #include <sys/prctl.h>
-#include <proc/readproc.h>
+# if defined(USING_LIBPROC2)
+#  include <libproc2/pids.h>
+# else
+#  include <proc/readproc.h>
+# endif
 #elif defined(Q_OS_FREEBSD)
 #include <sys/procctl.h>
 #include <libutil.h>
@@ -109,6 +113,23 @@ void ProcReaper::stop(const std::set<int64_t> & excludedPids)
     const pid_t my_pid = ::getpid();
     std::vector<pid_t> children;
 #if defined(Q_OS_LINUX)
+# if defined(USING_LIBPROC2)
+    constexpr pids_item items[] = { PIDS_ID_PPID, PIDS_ID_TGID };
+    enum rel_items { rel_ppid, rel_tgid };
+    pids_info * info = nullptr;
+    procps_pids_new(&info, const_cast<pids_item *>(items), sizeof(items) / sizeof(pids_item));
+    pids_stack * stack = nullptr;
+    while ((stack = procps_pids_get(info, PIDS_FETCH_TASKS_ONLY)))
+    {
+        const int ppid = PIDS_VAL(rel_ppid, s_int, stack, info);
+        if (ppid == my_pid)
+        {
+            const int tgid = PIDS_VAL(rel_tgid, s_int, stack, info);
+            children.push_back(tgid);
+        }
+    }
+    procps_pids_unref(&info);
+# else
     PROCTAB * proc_dir = ::openproc(PROC_FILLSTAT);
     while (proc_t * proc = ::readproc(proc_dir, nullptr))
     {
@@ -119,6 +140,7 @@ void ProcReaper::stop(const std::set<int64_t> & excludedPids)
         ::freeproc(proc);
     }
     ::closeproc(proc_dir);
+# endif
 #elif defined(Q_OS_FREEBSD)
     int cnt = 0;
     if (kinfo_proc *proc_info = kinfo_getallproc(&cnt))
-- 
2.39.2