mirror of
https://github.com/SerenityOS/serenity
synced 2024-09-06 17:06:31 +00:00
182 lines
6.1 KiB
C++
182 lines
6.1 KiB
C++
/*
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* Copyright (c) 2020, the SerenityOS developers.
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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/String.h>
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#include <AK/Types.h>
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#include <AK/Userspace.h>
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#include <Kernel/StdLib.h>
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#include <Kernel/UnixTypes.h>
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#include <Kernel/VM/MemoryManager.h>
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#include <LibC/errno_numbers.h>
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namespace Kernel {
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class UserOrKernelBuffer {
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public:
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UserOrKernelBuffer() = delete;
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static UserOrKernelBuffer for_kernel_buffer(u8* kernel_buffer)
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{
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ASSERT(!kernel_buffer || !is_user_address(VirtualAddress(kernel_buffer)));
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return UserOrKernelBuffer(kernel_buffer);
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}
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static Optional<UserOrKernelBuffer> for_user_buffer(u8* user_buffer, size_t size)
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{
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if (user_buffer && !is_user_range(VirtualAddress(user_buffer), size))
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return {};
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return UserOrKernelBuffer(user_buffer);
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}
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template<typename UserspaceType>
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static Optional<UserOrKernelBuffer> for_user_buffer(UserspaceType userspace, size_t size)
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{
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if (!is_user_range(VirtualAddress(userspace.unsafe_userspace_ptr()), size))
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return {};
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return UserOrKernelBuffer(const_cast<u8*>((const u8*)userspace.unsafe_userspace_ptr()));
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}
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bool is_kernel_buffer() const;
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const void* user_or_kernel_ptr() const { return m_buffer; }
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UserOrKernelBuffer offset(ssize_t offset) const
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{
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if (!m_buffer)
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return *this;
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UserOrKernelBuffer offset_buffer = *this;
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offset_buffer.m_buffer += offset;
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ASSERT(offset_buffer.is_kernel_buffer() == is_kernel_buffer());
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return offset_buffer;
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}
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String copy_into_string(size_t size) const;
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[[nodiscard]] bool write(const void* src, size_t offset, size_t len);
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[[nodiscard]] bool write(const void* src, size_t len)
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{
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return write(src, 0, len);
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}
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[[nodiscard]] bool write(ReadonlyBytes bytes)
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{
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return write(bytes.data(), bytes.size());
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}
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[[nodiscard]] bool read(void* dest, size_t offset, size_t len) const;
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[[nodiscard]] bool read(void* dest, size_t len) const
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{
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return read(dest, 0, len);
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}
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[[nodiscard]] bool read(Bytes bytes) const
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{
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return read(bytes.data(), bytes.size());
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}
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[[nodiscard]] bool memset(int value, size_t offset, size_t len);
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[[nodiscard]] bool memset(int value, size_t len)
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{
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return memset(value, 0, len);
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}
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template<size_t BUFFER_BYTES, typename F>
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[[nodiscard]] ssize_t write_buffered(size_t offset, size_t len, F f)
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{
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if (!m_buffer)
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return -EFAULT;
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if (is_kernel_buffer()) {
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// We're transferring directly to a kernel buffer, bypass
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return f(m_buffer + offset, len);
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}
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// The purpose of using a buffer on the stack is that we can
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// avoid a bunch of small (e.g. 1-byte) copy_to_user calls
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u8 buffer[BUFFER_BYTES];
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size_t nwritten = 0;
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while (nwritten < len) {
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auto to_copy = min(sizeof(buffer), len - nwritten);
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ssize_t copied = f(buffer, to_copy);
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if (copied < 0)
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return copied;
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ASSERT((size_t)copied <= to_copy);
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if (!write(buffer, nwritten, (size_t)copied))
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return -EFAULT;
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nwritten += (size_t)copied;
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if ((size_t)copied < to_copy)
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break;
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}
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return (ssize_t)nwritten;
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}
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template<size_t BUFFER_BYTES, typename F>
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[[nodiscard]] ssize_t write_buffered(size_t len, F f)
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{
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return write_buffered<BUFFER_BYTES, F>(0, len, f);
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}
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template<size_t BUFFER_BYTES, typename F>
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[[nodiscard]] ssize_t read_buffered(size_t offset, size_t len, F f) const
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{
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if (!m_buffer)
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return -EFAULT;
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if (is_kernel_buffer()) {
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// We're transferring directly from a kernel buffer, bypass
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return f(m_buffer + offset, len);
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}
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// The purpose of using a buffer on the stack is that we can
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// avoid a bunch of small (e.g. 1-byte) copy_from_user calls
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u8 buffer[BUFFER_BYTES];
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size_t nread = 0;
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while (nread < len) {
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auto to_copy = min(sizeof(buffer), len - nread);
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if (!read(buffer, nread, to_copy))
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return -EFAULT;
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ssize_t copied = f(buffer, to_copy);
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if (copied < 0)
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return copied;
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ASSERT((size_t)copied <= to_copy);
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nread += (size_t)copied;
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if ((size_t)copied < to_copy)
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break;
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}
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return nread;
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}
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template<size_t BUFFER_BYTES, typename F>
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[[nodiscard]] ssize_t read_buffered(size_t len, F f) const
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{
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return read_buffered<BUFFER_BYTES, F>(0, len, f);
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}
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private:
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explicit UserOrKernelBuffer(u8* buffer)
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: m_buffer(buffer)
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{
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}
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u8* m_buffer;
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};
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}
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