guix/gnu/packages/patches/htop-fix-process-tree.patch

From 2971a187551e062ffefdab965f55377b36cd94eb Mon Sep 17 00:00:00 2001
From: Tobias Geerinckx-Rice <me@tobias.gr>
Date: Wed, 21 Feb 2018 06:00:50 +0100
Subject: [PATCH] Fix process tree
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This manually reverts:

  commit 584a9bceab948590dabd189d234a86e6bf4ec3f4
  Author: wangqr <wangqr@wangqr.tk>
  Date:   Fri Sep 1 21:27:24 2017 +0800

  Find roots when constructing process tree, fix #587

which breaks the process tree (‘t’) view in at least some cases.
I will investigate further...
---
 ProcessList.c | 63 +++++++++++++++++------------------------------------------
 1 file changed, 18 insertions(+), 45 deletions(-)

diff --git a/ProcessList.c b/ProcessList.c
index 48b2d95..225253d 100644
--- a/ProcessList.c
+++ b/ProcessList.c
@@ -213,51 +213,24 @@ void ProcessList_sort(ProcessList* this) {
       // Restore settings
       this->settings->sortKey = sortKey;
       this->settings->direction = direction;
-      int vsize = Vector_size(this->processes);
-      // Find all processes whose parent is not visible
-      int size;
-      while ((size = Vector_size(this->processes))) {
-         int i;
-         for (i = 0; i < size; i++) {
-            Process* process = (Process*)(Vector_get(this->processes, i));
-            // Immediately consume not shown processes
-            if (!process->show) {
-               process = (Process*)(Vector_take(this->processes, i));
-               process->indent = 0;
-               Vector_add(this->processes2, process);
-               ProcessList_buildTree(this, process->pid, 0, 0, direction, false);
-               break;
-            }
-            pid_t ppid = process->tgid == process->pid ? process->ppid : process->tgid;
-            // Bisect the process vector to find parent
-            int l = 0, r = size;
-            // If PID corresponds with PPID (e.g. "kernel_task" (PID:0, PPID:0)
-            // on Mac OS X 10.11.6) cancel bisecting and regard this process as
-            // root.
-            if (process->pid == ppid)
-               r = 0;
-            while (l < r) {
-               int c = (l + r) / 2;
-               pid_t pid = ((Process*)(Vector_get(this->processes, c)))->pid;
-               if (ppid == pid) {
-                  break;
-               } else if (ppid < pid) {
-                  r = c;
-               } else {
-                  l = c + 1;
-               }
-            }
-            // If parent not found, then construct the tree with this root
-            if (l >= r) {
-               process = (Process*)(Vector_take(this->processes, i));
-               process->indent = 0;
-               Vector_add(this->processes2, process);
-               ProcessList_buildTree(this, process->pid, 0, 0, direction, process->showChildren);
-               break;
-            }
-         }
-         // There should be no loop in the process tree
-         assert(i < size);
+
+      // Take PID 1 as root and add to the new listing
+       int vsize = Vector_size(this->processes);
+      Process* init = (Process*) (Vector_take(this->processes, 0));
+      if (!init) return;
+      // This assertion crashes on hardened kernels.
+      // I wonder how well tree view works on those systems.
+      // assert(init->pid == 1);
+      init->indent = 0;
+      Vector_add(this->processes2, init);
+      // Recursively empty list
+      ProcessList_buildTree(this, init->pid, 0, 0, direction, true);
+      // Add leftovers
+      while (Vector_size(this->processes)) {
+         Process* p = (Process*) (Vector_take(this->processes, 0));
+         p->indent = 0;
+         Vector_add(this->processes2, p);
+         ProcessList_buildTree(this, p->pid, 0, 0, direction, p->showChildren);
       }
       assert(Vector_size(this->processes2) == vsize); (void)vsize;
       assert(Vector_size(this->processes) == 0);
-- 
2.16.2