server: Split get_thread_from_pid to allow lookups by tid or pid only.

server/ptrace.c

@@ -144,7 +144,12 @@ void sigchld_callback(void)
     for (;;)
     {
         if (!(pid = wait4_wrapper( -1, &status, WUNTRACED | WNOHANG, NULL ))) break;
-        if (pid != -1) handle_child_status( get_thread_from_pid(pid), pid, status, -1 );
+        if (pid != -1)
+        {
+            struct thread *thread = get_thread_from_tid( pid );
+            if (!thread) thread = get_thread_from_pid( pid );
+            handle_child_status( thread, pid, status, -1 );
+        }
         else break;
     }
 }

server/thread.c

@@ -297,15 +297,23 @@ struct thread *get_thread_from_handle( obj_handle_t handle, unsigned int access
                                             access, &thread_ops );
 }
 
-/* find a thread from a Unix pid */
-struct thread *get_thread_from_pid( int pid )
+/* find a thread from a Unix tid */
+struct thread *get_thread_from_tid( int tid )
 {
     struct thread *thread;
 
     LIST_FOR_EACH_ENTRY( thread, &thread_list, struct thread, entry )
     {
-        if (thread->unix_tid == pid) return thread;
+        if (thread->unix_tid == tid) return thread;
     }
+    return NULL;
+}
+
+/* find a thread from a Unix pid */
+struct thread *get_thread_from_pid( int pid )
+{
+    struct thread *thread;
+
     LIST_FOR_EACH_ENTRY( thread, &thread_list, struct thread, entry )
     {
         if (thread->unix_pid == pid) return thread;

server/thread.h

@@ -103,6 +103,7 @@ extern struct thread *current;
 extern struct thread *create_thread( int fd, struct process *process );
 extern struct thread *get_thread_from_id( thread_id_t id );
 extern struct thread *get_thread_from_handle( obj_handle_t handle, unsigned int access );
+extern struct thread *get_thread_from_tid( int tid );
 extern struct thread *get_thread_from_pid( int pid );
 extern void stop_thread( struct thread *thread );
 extern int wake_thread( struct thread *thread );