Kernel+LibC: Add sys$disown() for disowning child processes

This syscall allows a parent process to disown a child process, setting
its parent PID to 0.

Unparented processes are automatically reaped by the kernel upon exit,
and no sys$waitid() is required. This will make it much nicer to do
spawn-and-forget which is common in the GUI environment.

2 files changed, 8 insertions, 0 deletions

diff --git a/Libraries/LibC/serenity.cpp b/Libraries/LibC/serenity.cpp
index 68e10accb0..5837aee15f 100644
--- a/Libraries/LibC/serenity.cpp
+++ b/Libraries/LibC/serenity.cpp
@@ -30,6 +30,12 @@
 
 extern "C" {
 
+int disown(pid_t pid)
+{
+    int rc = syscall(SC_disown, pid);
+    __RETURN_WITH_ERRNO(rc, rc, -1);
+}
+
 int module_load(const char* path, size_t path_length)
 {
     int rc = syscall(SC_module_load, path, path_length);
diff --git a/Libraries/LibC/serenity.h b/Libraries/LibC/serenity.h
index 6ed6bba428..55423f13c2 100644
--- a/Libraries/LibC/serenity.h
+++ b/Libraries/LibC/serenity.h
@@ -31,6 +31,8 @@
 
 __BEGIN_DECLS
 
+int disown(pid_t);
+
 int shbuf_create(int, void** buffer);
 int shbuf_allow_pid(int, pid_t peer_pid);
 int shbuf_allow_all(int);