Kernel+LibPthread: Implement pthread_detach()

Author: https://github.com/awesomekling
Commit: https://github.com/SerenityOS/serenity/commit/95b086f47f4

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))

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);

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 {
 

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