diff --git a/kernel/include/kernel/Process.h b/kernel/include/kernel/Process.h
index 6eb394ca..3db255dc 100644
--- a/kernel/include/kernel/Process.h
+++ b/kernel/include/kernel/Process.h
@@ -176,7 +176,7 @@ namespace Kernel
 		BAN::ErrorOr<long> sys_smo_delete(SharedMemoryObjectManager::Key);
 		BAN::ErrorOr<long> sys_smo_map(SharedMemoryObjectManager::Key);
 
-		BAN::ErrorOr<long> sys_ttyname(int fildes, char* storage);
+		BAN::ErrorOr<long> sys_ttyname(int fildes, char* name, size_t namesize);
 		BAN::ErrorOr<long> sys_isatty(int fildes);
 		BAN::ErrorOr<long> sys_posix_openpt(int flags);
 		BAN::ErrorOr<long> sys_ptsname(int fildes, char* buffer, size_t buffer_len);
diff --git a/kernel/kernel/Process.cpp b/kernel/kernel/Process.cpp
index 74e70a3f..ac424de5 100644
--- a/kernel/kernel/Process.cpp
+++ b/kernel/kernel/Process.cpp
@@ -2275,17 +2275,17 @@ namespace Kernel
 		return m_mapped_regions.back()->vaddr();
 	}
 
-	BAN::ErrorOr<long> Process::sys_ttyname(int fildes, char* storage)
+	BAN::ErrorOr<long> Process::sys_ttyname(int fildes, char* name, size_t namesize)
 	{
 		LockGuard _(m_process_lock);
-		TRY(validate_pointer_access(storage, TTY_NAME_MAX, true));
+		TRY(validate_pointer_access(name, namesize, true));
 		auto inode = TRY(m_open_file_descriptors.inode_of(fildes));
 		if (!inode->is_tty())
 			return BAN::Error::from_errno(ENOTTY);
 		auto path = TRY(m_open_file_descriptors.path_of(fildes));
-		ASSERT(path.size() < TTY_NAME_MAX);
-		strncpy(storage, path.data(), path.size());
-		storage[path.size()] = '\0';
+		if (namesize < path.size() + 1)
+			return BAN::Error::from_errno(ERANGE);
+		strcpy(name, path.data());
 		return 0;
 	}
 
diff --git a/userspace/libraries/LibC/unistd.cpp b/userspace/libraries/LibC/unistd.cpp
index 1f57d1ed..19d9a8ce 100644
--- a/userspace/libraries/LibC/unistd.cpp
+++ b/userspace/libraries/LibC/unistd.cpp
@@ -787,12 +787,19 @@ char* getlogin(void)
 
 char* ttyname(int fildes)
 {
-	static char storage[_POSIX_TTY_NAME_MAX];
-	if (syscall(SYS_TTYNAME, fildes, storage) == -1)
+	static char storage[TTY_NAME_MAX];
+	if (ttyname_r(fildes, storage, sizeof(storage)) != 0)
 		return nullptr;
 	return storage;
 }
 
+int ttyname_r(int fildes, char* name, size_t namesize)
+{
+	if (syscall(SYS_TTYNAME, fildes, name, namesize))
+		return errno;
+	return 0;
+}
+
 int access(const char* path, int amode)
 {
 	return syscall(SYS_ACCESS, path, amode);