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https://github.com/RGBCube/serenity
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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.
47 lines
1.4 KiB
C++
47 lines
1.4 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 <AK/StringView.h>
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#include <Kernel/FileSystem/FileDescription.h>
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#include <Kernel/FileSystem/VirtualFileSystem.h>
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#include <Kernel/Process.h>
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namespace Kernel {
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KResultOr<FlatPtr> Process::sys$readlink(Userspace<const Syscall::SC_readlink_params*> user_params)
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{
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VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
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REQUIRE_PROMISE(rpath);
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Syscall::SC_readlink_params params;
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if (!copy_from_user(¶ms, user_params))
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return EFAULT;
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auto path = get_syscall_path_argument(params.path);
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if (path.is_error())
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return path.error();
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auto result = VirtualFileSystem::the().open(path.value()->view(), O_RDONLY | O_NOFOLLOW_NOERROR, 0, current_directory());
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if (result.is_error())
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return result.error();
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auto description = result.value();
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if (!description->metadata().is_symlink())
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return EINVAL;
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auto contents = description->read_entire_file();
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if (contents.is_error())
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return contents.error();
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auto& link_target = *contents.value();
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auto size_to_copy = min(link_target.size(), params.buffer.size);
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if (!copy_to_user(params.buffer.data, link_target.data(), size_to_copy))
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return EFAULT;
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// Note: we return the whole size here, not the copied size.
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return link_target.size();
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}
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}
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