From 95b086f47f4f63eadcb70c9b817739db77a0e197 Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Sat, 7 Dec 2019 14:47:00 +0100
Subject: [PATCH] Kernel+LibPthread: Implement pthread_detach()

---
 Kernel/Process.cpp               | 21 +++++++++++++++++++++
 Kernel/Process.h                 |  1 +
 Kernel/Syscall.h                 |  3 ++-
 Libraries/LibPthread/pthread.cpp |  5 +++++
 4 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/Kernel/Process.cpp b/Kernel/Process.cpp
index b7041c190a8..be12cef9377 100644
--- a/Kernel/Process.cpp
+++ b/Kernel/Process.cpp
@@ -2915,6 +2915,27 @@ void Process::sys$exit_thread(void* exit_value)
     ASSERT_NOT_REACHED();
 }
 
+int Process::sys$detach_thread(int tid)
+{
+    Thread* thread = nullptr;
+    for_each_thread([&](auto& child_thread) {
+        if (child_thread.tid() == tid) {
+            thread = &child_thread;
+            return IterationDecision::Break;
+        }
+        return IterationDecision::Continue;
+    });
+
+    if (!thread)
+        return -ESRCH;
+
+    if (!thread->is_joinable())
+        return -EINVAL;
+
+    thread->set_joinable(false);
+    return 0;
+}
+
 int Process::sys$join_thread(int tid, void** exit_value)
 {
     if (exit_value && !validate_write_typed(exit_value))
diff --git a/Kernel/Process.h b/Kernel/Process.h
index 192605afee3..bfa31ee58de 100644
--- a/Kernel/Process.h
+++ b/Kernel/Process.h
@@ -204,6 +204,7 @@ public:
     int sys$create_thread(void* (*)(void*), void* argument, const Syscall::SC_create_thread_params*);
     void sys$exit_thread(void*);
     int sys$join_thread(int tid, void** exit_value);
+    int sys$detach_thread(int tid);
     int sys$rename(const char* oldpath, const char* newpath);
     int sys$systrace(pid_t);
     int sys$mknod(const char* pathname, mode_t, dev_t);
diff --git a/Kernel/Syscall.h b/Kernel/Syscall.h
index d72199f55ba..dcafa120e2d 100644
--- a/Kernel/Syscall.h
+++ b/Kernel/Syscall.h
@@ -141,7 +141,8 @@ typedef u32 socklen_t;
     __ENUMERATE_SYSCALL(openat)                 \
     __ENUMERATE_SYSCALL(join_thread)            \
     __ENUMERATE_SYSCALL(module_load)            \
-    __ENUMERATE_SYSCALL(module_unload)
+    __ENUMERATE_SYSCALL(module_unload)          \
+    __ENUMERATE_SYSCALL(detach_thread)
 
 namespace Syscall {
 
diff --git a/Libraries/LibPthread/pthread.cpp b/Libraries/LibPthread/pthread.cpp
index d3a54b8e69f..8e5e368005d 100644
--- a/Libraries/LibPthread/pthread.cpp
+++ b/Libraries/LibPthread/pthread.cpp
@@ -85,6 +85,11 @@ int pthread_join(pthread_t thread, void** exit_value_ptr)
     return syscall(SC_join_thread, thread, exit_value_ptr);
 }
 
+int pthread_detach(pthread_t thread)
+{
+    return syscall(SC_detach_thread, thread);
+}
+
 int pthread_mutex_init(pthread_mutex_t* mutex, const pthread_mutexattr_t* attributes)
 {
     // FIXME: Implement mutex attributes