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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <Kernel/FileSystem/FileDescription.h>
#include <Kernel/Process.h>
//#define DEBUG_IO
namespace Kernel {
ssize_t Process::sys$read(int fd, Userspace<u8*> buffer, ssize_t size)
{
REQUIRE_PROMISE(stdio);
if (size < 0)
return -EINVAL;
if (size == 0)
return 0;
#ifdef DEBUG_IO
dbg() << "sys$read(" << fd << ", " << (const void*)buffer.ptr() << ", " << size << ")";
#endif
auto description = file_description(fd);
if (!description)
return -EBADF;
if (!description->is_readable())
return -EBADF;
if (description->is_directory())
return -EISDIR;
if (description->is_blocking()) {
if (!description->can_read()) {
auto unblock_flags = Thread::FileBlocker::BlockFlags::None;
if (Thread::current()->block<Thread::ReadBlocker>({}, *description, unblock_flags).was_interrupted())
return -EINTR;
if (!((u32)unblock_flags & (u32)Thread::FileBlocker::BlockFlags::Read))
return -EAGAIN;
// TODO: handle exceptions in unblock_flags
}
}
auto user_buffer = UserOrKernelBuffer::for_user_buffer(buffer, size);
if (!user_buffer.has_value())
return -EFAULT;
auto result = description->read(user_buffer.value(), size);
if (result.is_error())
return result.error();
return result.value();
}
}
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