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c8d9f1b9c9
Since the CPU already does almost all necessary validation steps for us, we don't really need to attempt to do this. Doing it ourselves doesn't really work very reliably, because we'd have to account for other processors modifying virtual memory, and we'd have to account for e.g. pages not being able to be allocated due to insufficient resources. So change the copy_to/from_user (and associated helper functions) to use the new safe_memcpy, which will return whether it succeeded or not. The only manual validation step needed (which the CPU can't perform for us) is making sure the pointers provided by user mode aren't pointing to kernel mappings. To make it easier to read/write from/to either kernel or user mode data add the UserOrKernelBuffer helper class, which will internally either use copy_from/to_user or directly memcpy, or pass the data through directly using a temporary buffer on the stack. Last but not least we need to keep syscall params trivial as we need to copy them from/to user mode using copy_from/to_user.
103 lines
3.7 KiB
C++
103 lines
3.7 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#pragma once
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#include <AK/CircularDeque.h>
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#include <AK/WeakPtr.h>
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#include <Kernel/Devices/CharacterDevice.h>
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#include <Kernel/DoubleBuffer.h>
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#include <Kernel/ProcessGroup.h>
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#include <Kernel/UnixTypes.h>
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namespace Kernel {
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class TTY : public CharacterDevice {
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public:
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virtual ~TTY() override;
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virtual KResultOr<size_t> read(FileDescription&, size_t, UserOrKernelBuffer&, size_t) override;
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virtual KResultOr<size_t> write(FileDescription&, size_t, const UserOrKernelBuffer&, size_t) override;
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virtual bool can_read(const FileDescription&, size_t) const override;
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virtual bool can_write(const FileDescription&, size_t) const override;
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virtual int ioctl(FileDescription&, unsigned request, FlatPtr arg) override final;
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virtual String absolute_path(const FileDescription&) const override { return tty_name(); }
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virtual String tty_name() const = 0;
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unsigned short rows() const { return m_rows; }
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unsigned short columns() const { return m_columns; }
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ProcessGroupID pgid() const { return m_pg ? m_pg->pgid() : 0; }
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void set_termios(const termios&);
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bool should_generate_signals() const { return m_termios.c_lflag & ISIG; }
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bool should_flush_on_signal() const { return !(m_termios.c_lflag & NOFLSH); }
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bool should_echo_input() const { return m_termios.c_lflag & ECHO; }
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bool in_canonical_mode() const { return m_termios.c_lflag & ICANON; }
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void set_default_termios();
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void hang_up();
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protected:
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virtual ssize_t on_tty_write(const UserOrKernelBuffer&, ssize_t) = 0;
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void set_size(unsigned short columns, unsigned short rows);
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TTY(unsigned major, unsigned minor);
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void emit(u8);
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virtual void echo(u8) = 0;
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bool can_do_backspace() const;
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void do_backspace();
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void erase_word();
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void erase_character();
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void kill_line();
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void flush_input();
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bool is_eol(u8) const;
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bool is_eof(u8) const;
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bool is_kill(u8) const;
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bool is_erase(u8) const;
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bool is_werase(u8) const;
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void generate_signal(int signal);
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int m_available_lines { 0 };
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private:
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// ^CharacterDevice
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virtual bool is_tty() const final override { return true; }
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CircularDeque<u8, 1024> m_input_buffer;
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WeakPtr<Process> m_original_process_parent;
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WeakPtr<ProcessGroup> m_pg;
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termios m_termios;
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unsigned short m_rows { 0 };
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unsigned short m_columns { 0 };
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};
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}
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