From 1658df9b6e7441c49db005ea5812bbc10a562818 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Tue, 2 Feb 2021 19:48:39 +0100
Subject: [PATCH] LibC: Add LibC wrapper for sys$readlink()

To avoid having to make direct syscalls in LibCore, let's add a wrapper
for the kernel's readlink syscall in LibC.
---
 Userland/Libraries/LibC/serenity.cpp | 13 ++++++++++++-
 Userland/Libraries/LibC/serenity.h   |  5 ++++-
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/Userland/Libraries/LibC/serenity.cpp b/Userland/Libraries/LibC/serenity.cpp
index 5fade72705..7f2bf8364f 100644
--- a/Userland/Libraries/LibC/serenity.cpp
+++ b/Userland/Libraries/LibC/serenity.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -27,6 +27,7 @@
 #include <Kernel/API/Syscall.h>
 #include <errno.h>
 #include <serenity.h>
+#include <string.h>
 
 extern "C" {
 
@@ -118,4 +119,14 @@ int anon_create(size_t size, int options)
     int rc = syscall(SC_anon_create, size, options);
     __RETURN_WITH_ERRNO(rc, rc, -1);
 }
+
+int serenity_readlink(const char* path, size_t path_length, char* buffer, size_t buffer_size)
+{
+    Syscall::SC_readlink_params small_params {
+        { path, path_length },
+        { buffer, buffer_size }
+    };
+    int rc = syscall(SC_readlink, &small_params);
+    __RETURN_WITH_ERRNO(rc, rc, -1);
+}
 }
diff --git a/Userland/Libraries/LibC/serenity.h b/Userland/Libraries/LibC/serenity.h
index 7aa4f97a6c..d2e3b8f96b 100644
--- a/Userland/Libraries/LibC/serenity.h
+++ b/Userland/Libraries/LibC/serenity.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -28,6 +28,7 @@
 
 #include <stdio.h>
 #include <unistd.h>
+#include <sys/types.h>
 
 __BEGIN_DECLS
 
@@ -103,6 +104,8 @@ int get_stack_bounds(uintptr_t* user_stack_base, size_t* user_stack_size);
 
 int anon_create(size_t size, int options);
 
+int serenity_readlink(const char* path, size_t path_length, char* buffer, size_t buffer_size);
+
 #ifdef __i386__
 ALWAYS_INLINE void send_secret_data_to_userspace_emulator(uintptr_t data1, uintptr_t data2, uintptr_t data3)
 {