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	 c3351d4b9f
			
		
	
	
		c3351d4b9f
		
	
	
	
	
		
			
			Instead of getting credentials from Process::current(), we now require that they be provided as input to the various VFS functions. This ensures that an atomic set of credentials is used throughout an entire VFS operation.
		
			
				
	
	
		
			61 lines
		
	
	
	
		
			2 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			61 lines
		
	
	
	
		
			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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| 
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| #include <AK/RefPtr.h>
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| #include <Kernel/FileSystem/Custody.h>
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| #include <Kernel/FileSystem/VirtualFileSystem.h>
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| #include <Kernel/Process.h>
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| 
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| namespace Kernel {
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| 
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| ErrorOr<FlatPtr> Process::sys$chdir(Userspace<char const*> user_path, size_t path_length)
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| {
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|     VERIFY_NO_PROCESS_BIG_LOCK(this);
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|     TRY(require_promise(Pledge::rpath));
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|     auto path = TRY(get_syscall_path_argument(user_path, path_length));
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|     auto current_directory = m_current_directory.with([](auto& current_directory) -> NonnullRefPtr<Custody> {
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|         return *current_directory;
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|     });
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|     RefPtr<Custody> new_directory = TRY(VirtualFileSystem::the().open_directory(credentials(), path->view(), *current_directory));
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|     m_current_directory.with([&](auto& current_directory) {
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|         // NOTE: We use swap() here to avoid manipulating the ref counts while holding the lock.
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|         swap(current_directory, new_directory);
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|     });
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|     return 0;
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| }
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| 
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| ErrorOr<FlatPtr> Process::sys$fchdir(int fd)
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| {
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|     VERIFY_NO_PROCESS_BIG_LOCK(this);
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|     TRY(require_promise(Pledge::stdio));
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|     auto description = TRY(open_file_description(fd));
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|     if (!description->is_directory())
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|         return ENOTDIR;
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|     if (!description->metadata().may_execute(credentials()))
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|         return EACCES;
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|     m_current_directory.with([&](auto& current_directory) {
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|         current_directory = description->custody();
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|     });
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|     return 0;
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| }
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| 
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| ErrorOr<FlatPtr> Process::sys$getcwd(Userspace<char*> buffer, size_t size)
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| {
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|     VERIFY_NO_PROCESS_BIG_LOCK(this);
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|     TRY(require_promise(Pledge::rpath));
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| 
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|     if (size > NumericLimits<ssize_t>::max())
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|         return EINVAL;
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| 
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|     auto path = TRY(current_directory()->try_serialize_absolute_path());
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|     size_t ideal_size = path->length() + 1;
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|     auto size_to_copy = min(ideal_size, size);
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|     TRY(copy_to_user(buffer, path->characters(), size_to_copy));
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|     // Note: we return the whole size here, not the copied size.
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|     return ideal_size;
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| }
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| 
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| }
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