From 0d89cfcd9a4ef7c0d5aa283747e09bbe392e61b7 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Sat, 17 Jul 2021 22:11:41 +0200
Subject: [PATCH] Kernel/DevFS: Use KString for DevFSLinkInode::m_link

---
 Kernel/FileSystem/DevFS.cpp | 14 +++++++++-----
 Kernel/FileSystem/DevFS.h   |  2 +-
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/Kernel/FileSystem/DevFS.cpp b/Kernel/FileSystem/DevFS.cpp
index 94bb95e72c..4321f92218 100644
--- a/Kernel/FileSystem/DevFS.cpp
+++ b/Kernel/FileSystem/DevFS.cpp
@@ -158,10 +158,10 @@ KResultOr<size_t> DevFSLinkInode::read_bytes(off_t offset, size_t, UserOrKernelB
 {
     Locker locker(m_inode_lock);
     VERIFY(offset == 0);
-    VERIFY(!m_link.is_null());
-    if (!buffer.write(((const u8*)m_link.substring_view(0).characters_without_null_termination()) + offset, m_link.length()))
+    VERIFY(m_link);
+    if (!buffer.write(m_link->characters() + offset, m_link->length()))
         return EFAULT;
-    return m_link.length();
+    return m_link->length();
 }
 
 InodeMetadata DevFSLinkInode::metadata() const
@@ -176,12 +176,16 @@ InodeMetadata DevFSLinkInode::metadata() const
     return metadata;
 }
 
-KResultOr<size_t> DevFSLinkInode::write_bytes(off_t offset, size_t count, const UserOrKernelBuffer& buffer, FileDescription*)
+KResultOr<size_t> DevFSLinkInode::write_bytes(off_t offset, size_t count, UserOrKernelBuffer const& buffer, FileDescription*)
 {
+    auto kstring_or_error = buffer.try_copy_into_kstring(count);
+    if (kstring_or_error.is_error())
+        return kstring_or_error.error();
+
     Locker locker(m_inode_lock);
     VERIFY(offset == 0);
     VERIFY(buffer.is_kernel_buffer());
-    m_link = buffer.copy_into_string(count);
+    m_link = kstring_or_error.release_value();
     return count;
 }
 
diff --git a/Kernel/FileSystem/DevFS.h b/Kernel/FileSystem/DevFS.h
index fed150869c..a0782f6ac9 100644
--- a/Kernel/FileSystem/DevFS.h
+++ b/Kernel/FileSystem/DevFS.h
@@ -104,7 +104,7 @@ protected:
     virtual KResultOr<size_t> write_bytes(off_t, size_t, const UserOrKernelBuffer& buffer, FileDescription*) override;
 
     NonnullOwnPtr<KString> m_name;
-    String m_link;
+    OwnPtr<KString> m_link;
 };
 
 class DevFSDirectoryInode : public DevFSInode {