From 29b103c3762d01c9711aba33985f27869238143d Mon Sep 17 00:00:00 2001
From: Nikolai Nechaev <nikolay_nechaev@mail.ru>
Date: Wed, 24 Sep 2025 02:32:48 +0900
Subject: exec: Spawn processes as direct children (#11735)

* exec: Spawn processes as direct children

Spawn processes as children rather than grandchildren.
This way, spawned processes may track Hyprland's state
by watching their parent, either directly or indirectly
(e.g., Linux's `PR_SET_PDEATH_SIG`).

Fixes #11728

* tests/exec: Add the test on process spawning

Add a test that ensures that:
- A spawned process remains a direct child of Hyprland;
- Upon termination, the process does not become a zombie.
---
 src/managers/KeybindManager.cpp | 53 +++++++++++++----------------------------
 1 file changed, 16 insertions(+), 37 deletions(-)

(limited to 'src/managers/KeybindManager.cpp')

diff --git a/src/managers/KeybindManager.cpp b/src/managers/KeybindManager.cpp
index cd69289e..3120157f 100644
--- a/src/managers/KeybindManager.cpp
+++ b/src/managers/KeybindManager.cpp
@@ -949,17 +949,9 @@ uint64_t CKeybindManager::spawnRawProc(std::string args, PHLWORKSPACE pInitialWo
 
     const auto HLENV = getHyprlandLaunchEnv(pInitialWorkspace);
 
-    int        socket[2];
-    if (pipe(socket) != 0) {
-        Debug::log(LOG, "Unable to create pipe for fork");
-    }
-
-    CFileDescriptor pipeSock[2] = {CFileDescriptor{socket[0]}, CFileDescriptor{socket[1]}};
-
-    pid_t           child, grandchild;
-    child = fork();
+    pid_t      child = fork();
     if (child < 0) {
-        Debug::log(LOG, "Fail to create the first fork");
+        Debug::log(LOG, "Fail to fork");
         return 0;
     }
     if (child == 0) {
@@ -970,41 +962,28 @@ uint64_t CKeybindManager::spawnRawProc(std::string args, PHLWORKSPACE pInitialWo
         sigemptyset(&set);
         sigprocmask(SIG_SETMASK, &set, nullptr);
 
-        grandchild = fork();
-        if (grandchild == 0) {
-            // run in grandchild
-            for (auto const& e : HLENV) {
-                setenv(e.first.c_str(), e.second.c_str(), 1);
-            }
-            setenv("WAYLAND_DISPLAY", g_pCompositor->m_wlDisplaySocket.c_str(), 1);
-
-            int devnull = open("/dev/null", O_WRONLY | O_CLOEXEC);
-            if (devnull != -1) {
-                dup2(devnull, STDOUT_FILENO);
-                dup2(devnull, STDERR_FILENO);
-                close(devnull);
-            }
+        for (auto const& e : HLENV) {
+            setenv(e.first.c_str(), e.second.c_str(), 1);
+        }
+        setenv("WAYLAND_DISPLAY", g_pCompositor->m_wlDisplaySocket.c_str(), 1);
 
-            execl("/bin/sh", "/bin/sh", "-c", args.c_str(), nullptr);
-            // exit grandchild
-            _exit(0);
+        int devnull = open("/dev/null", O_WRONLY | O_CLOEXEC);
+        if (devnull != -1) {
+            dup2(devnull, STDOUT_FILENO);
+            dup2(devnull, STDERR_FILENO);
+            close(devnull);
         }
-        write(pipeSock[1].get(), &grandchild, sizeof(grandchild));
+
+        execl("/bin/sh", "/bin/sh", "-c", args.c_str(), nullptr);
+
         // exit child
         _exit(0);
     }
     // run in parent
-    read(pipeSock[0].get(), &grandchild, sizeof(grandchild));
-    // clear child and leave grandchild to init
-    waitpid(child, nullptr, 0);
-    if (grandchild < 0) {
-        Debug::log(LOG, "Fail to create the second fork");
-        return 0;
-    }
 
-    Debug::log(LOG, "Process Created with pid {}", grandchild);
+    Debug::log(LOG, "Process Created with pid {}", child);
 
-    return grandchild;
+    return child;
 }
 
 SDispatchResult CKeybindManager::killActive(std::string args) {
-- 
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