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9201a06027
Before we start disabling acquisition of the big process lock for specific syscalls, make sure to document and assert that all the lock is held during all syscalls.
108 lines
3.2 KiB
C++
108 lines
3.2 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <Kernel/Debug.h>
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#include <Kernel/FileSystem/FileDescription.h>
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#include <Kernel/Process.h>
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namespace Kernel {
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using BlockFlags = Thread::FileBlocker::BlockFlags;
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KResultOr<FlatPtr> Process::sys$readv(int fd, Userspace<const struct iovec*> iov, int iov_count)
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{
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VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
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REQUIRE_PROMISE(stdio);
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if (iov_count < 0)
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return EINVAL;
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// Arbitrary pain threshold.
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if (iov_count > (int)MiB)
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return EFAULT;
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u64 total_length = 0;
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Vector<iovec, 32> vecs;
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if (!vecs.try_resize(iov_count))
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return ENOMEM;
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if (!copy_n_from_user(vecs.data(), iov, iov_count))
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return EFAULT;
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for (auto& vec : vecs) {
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total_length += vec.iov_len;
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if (total_length > NumericLimits<i32>::max())
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return EINVAL;
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}
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auto description = fds().file_description(fd);
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if (!description)
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return EBADF;
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if (!description->is_readable())
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return EBADF;
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if (description->is_directory())
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return EISDIR;
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int nread = 0;
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for (auto& vec : vecs) {
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if (description->is_blocking()) {
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if (!description->can_read()) {
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auto unblock_flags = BlockFlags::None;
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if (Thread::current()->block<Thread::ReadBlocker>({}, *description, unblock_flags).was_interrupted())
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return EINTR;
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if (!has_flag(unblock_flags, BlockFlags::Read))
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return EAGAIN;
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// TODO: handle exceptions in unblock_flags
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}
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}
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auto buffer = UserOrKernelBuffer::for_user_buffer((u8*)vec.iov_base, vec.iov_len);
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if (!buffer.has_value())
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return EFAULT;
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auto result = description->read(buffer.value(), vec.iov_len);
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if (result.is_error())
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return result.error();
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nread += result.value();
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}
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return nread;
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}
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KResultOr<FlatPtr> Process::sys$read(int fd, Userspace<u8*> buffer, size_t size)
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{
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VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
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REQUIRE_PROMISE(stdio);
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if (size == 0)
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return 0;
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if (size > NumericLimits<ssize_t>::max())
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return EINVAL;
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dbgln_if(IO_DEBUG, "sys$read({}, {}, {})", fd, buffer.ptr(), size);
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auto description = fds().file_description(fd);
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if (!description)
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return EBADF;
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if (!description->is_readable())
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return EBADF;
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if (description->is_directory())
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return EISDIR;
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if (description->is_blocking()) {
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if (!description->can_read()) {
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auto unblock_flags = BlockFlags::None;
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if (Thread::current()->block<Thread::ReadBlocker>({}, *description, unblock_flags).was_interrupted())
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return EINTR;
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if (!has_flag(unblock_flags, BlockFlags::Read))
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return EAGAIN;
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// TODO: handle exceptions in unblock_flags
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}
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}
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auto user_buffer = UserOrKernelBuffer::for_user_buffer(buffer, size);
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if (!user_buffer.has_value())
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return EFAULT;
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auto result = description->read(user_buffer.value(), size);
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if (result.is_error())
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return result.error();
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return result.value();
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}
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}
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