start: add parent-death handling for BSDs (#12863)

* Add parent-death handling for BSDs

prctl() is a system call specific to Linux. So we cannot use it on BSDs.

FreeBSD has a system call procctl() which is similar to prctl(). We can
use it with PROC_PDEATHSIG_CTL.

OpenBSD, NetBSD, and DragonFly BSD do not appear to have a similar
mechanism. So intead of relying on a system call, we need to manually
poll ppid to see if the parent process has died.

With the changes, the spawned Hyprland process is terminated when the
launcher process exits, matching Linux behavior as closely as possible
on BSD platforms.

* Remove ppid polling on OpenBSD, NetBSD, and DragonFly BSD

1 files changed, 13 insertions, 2 deletions

diff --git a/start/src/core/Instance.cpp b/start/src/core/Instance.cpp
index c89d9d0b..ec56cc75 100644
--- a/start/src/core/Instance.cpp
+++ b/start/src/core/Instance.cpp
@@ -7,11 +7,17 @@
 #include <sys/poll.h>
 #include <sys/types.h>
 #include <sys/wait.h>
-#include <sys/prctl.h>
 #include <unistd.h>
 #include <ranges>
 #include <string_view>
 
+#if defined(__linux__)
+#include <sys/prctl.h>
+#elif defined(__FreeBSD__)
+#include <signal.h>
+#include <sys/procctl.h>
+#endif
+
 #include <hyprutils/os/Process.hpp>
 
 using namespace Hyprutils::OS;
@@ -41,7 +47,12 @@ void CHyprlandInstance::runHyprlandThread(bool safeMode) {
     int forkRet = fork();
     if (forkRet == 0) {
         // Make hyprland die on our SIGKILL
+#if defined(__linux__)
         prctl(PR_SET_PDEATHSIG, SIGKILL);
+#elif defined(__FreeBSD__)
+        int sig = SIGKILL;
+        procctl(P_PID, getpid(), PROC_PDEATHSIG_CTL, &sig);
+#endif
 
         execvp(g_state->customPath.value_or("Hyprland").c_str(), args.data());
 
@@ -164,4 +175,4 @@ bool CHyprlandInstance::run(bool safeMode) {
     m_hlThread.join();
 
     return !m_hyprlandInitialized || m_hyprlandExiting;
-}
\ No newline at end of file
+}