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620 lines
24 KiB
Plaintext
620 lines
24 KiB
Plaintext
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━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
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THE NEW SAMBA VFS
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Ralph Böhme, SerNet, Samba Team
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━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
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2021-01-14
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Table of Contents
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─────────────────
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1. The new VFS
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.. 1. Summary
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.. 2. Samba and O_PATH
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..... 1. Background
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..... 2. Usecases for O_PATH in Samba
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..... 3. When to open with O_PATH
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..... 4. Fallback on systems without O_PATH support
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..... 5. When to use fsp_get_io_fd() or fsp_get_pathref_fd()
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2. VFS status quo and remaining work
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.. 1. VFS Functions Tables [2]
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..... 1. Existing VFS Functions
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..... 2. New VFS Functions
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.. 2. VFS functions by category
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..... 1. Disk operations
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..... 2. Handle based VFS functions
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..... 3. Namespace changing VFS functions
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..... 4. Path based VFS functions
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..... 5. AT VFS functions that can't be based on handles
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..... 6. AT VFS functions needed for directory enumeration
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..... 7. Handle based VFS functions not allowed on O_PATH opened handles
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..... 8. Pure path to path translation
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..... 9. Special cases
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1 The new VFS
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═════════════
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1.1 Summary
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───────────
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The effort to modernize Samba's VFS interface has reached a major
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milestone with the next release Samba 4.14.
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Starting with version 4.14 Samba provides core infrastructure code that
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allows basing all access to the server's filesystem on file handles and
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not on paths. An example of this is using `fstat()' instead of `stat()',
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or `SMB_VFS_FSTAT()' instead of `SMB_VFS_STAT()' in Samba parlance.
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Historically Samba's fileserver code had to deal a lot with processing
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path based SMB requests. While the SMB protocol itself has been
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streamlined to be purely handle based starting with SMB2, large parts of
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infrastructure code remains in place that will "degrade" handle based SMB2
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requests to path based filesystem access.
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In order to fully leverage the handle based nature of the SMB2 protocol we
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came up with a straight forward way to convert this infrastructure code.
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At the core, we introduced a helper function that opens a file handle that
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only serves as a path reference and hence can not be used for any sort of
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access to file data.
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Samba's internal file handle structure is of type `struct files_struct'
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and all variable pointing to objects of such type are typically called
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`fsp'. Until very recently the only function that would open such a file
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handle and return an fsp was `SMB_VFS_CREATE_FILE()'.
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Internally `SMB_VFS_CREATE_FILE()' consisted of processing through Samba's
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VFS open function to open the low level file and then going through
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Samba's Windows NTFS emulation code.
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The key point of the new helper function which is called
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`openat_pathref_fsp()' is that it skips the NTFS emulation
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logic. Additionally, the handle is restricted internally to be only usable
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as a path reference but not for any sort of IO. On Linux this is achieved
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by using the `O_PATH' `open()' flag, on systems without `O_PATH' support
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other mechanisms are used described in more detail below.
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Path processing in Samba typically means processing client supplied paths
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by Samba's core path processing function `filename_convert()' which returs
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a pointer to an object of type `struct smb_filename'. Pointers to such
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objects are then passed around, often passing many layers of code.
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By attaching an `fsp' file handle returned from `openat_pathref_fsp()' to
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all `struct smb_filename' objects returned from `filename_convert()', the
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whole infrastructure code has immediate access to a file handle and so the
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large infrastructure codebase can be converted to use handle based VFS
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functions whenever VFS access is done in a piecemeal fashion.
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1.2 Samba and O_PATH
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────────────────────
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1.2.1 Background
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╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌
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On Linux the `O_PATH' flag to `open()' can be used to open a filehandle on
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a file or directory with interesting properties: [1]
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• the file-handle indicates a location in the filesystem tree,
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• no permission checks are done by the kernel on the filesystem object and
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• only operations that act purely at the file descriptor level are
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allowed.
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The file itself is not opened, and other file operations (e.g., `read(2)',
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`write(2)', `fchmod(2)', `fchown(2)', `fgetxattr(2)', `ioctl(2)',
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`mmap(2)') fail with the error `EBADF'.
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The following subset of operations that is relevant to Samba is allowed:
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• `close(2)',
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• `fchdir(2)', if the file descriptor refers to a directory,
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• `fstat(2)',
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• `fstatfs(2)' and
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• passing the file descriptor as the dirfd argument of `openat()' and the
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other "*at()" system calls. This includes `linkat(2)' with AT_EMPTY_PATH
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(or via procfs using AT_SYMLINK_FOLLOW) even if the file is not a
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directory.
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Opening a file or directory with the `O_PATH' flag requires no permissions
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on the object itself (but does require execute permission on the
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directories in the path prefix). By contrast, obtaining a reference to a
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filesystem object by opening it with the `O_RDONLY' flag requires that the
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caller have read permission on the object, even when the subsequent
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operation (e.g., `fchdir(2)', `fstat(2)') does not require read permis‐
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sion on the object.
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If for example Samba receives an SMB request to open a file requesting
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`SEC_FILE_READ_ATTRIBUTE' access rights because the client wants to read
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the file's metadata from the handle, Samba will have to call `open()' with
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at least `O_RDONLY' access rights.
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1.2.2 Usecases for O_PATH in Samba
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╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌
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The `O_PATH' flag is currently not used in Samba. By leveraging this Linux
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specific flags we can avoid permission mismatches as described above.
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Additionally `O_PATH' allows basing all filesystem accesses done by the
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fileserver on handle based syscalls by opening all client pathnames with
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`O_PATH' and consistently using for example `fstat()' instead of `stat()'
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throughout the codebase.
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Subsequent parts of this document will call such file-handles opened with
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O_PATH *path referencing file-handles* or *pathref*s for short.
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1.2.3 When to open with O_PATH
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╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌
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In Samba the decision whether to call POSIX `open()' on a client pathname
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or whether to leave the low-level handle at -1 (what we call a stat-open)
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is based on the client requested SMB acccess mask.
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The set of access rights that trigger an `open()' includes
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`READ_CONTROL_ACCESS'. As a result, the open() will be done with at least
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`O_RDONLY'. If the filesystem supports NT style ACLs natively (like GPFS
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or ZFS), the filesystem may grant the user requested right
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`READ_CONTROL_ACCESS', but it may not grant `READ_DATA' (`O_RDONLY').
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Currently the full set of access rights that trigger opening a file is:
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• FILE_READ_DATA
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• FILE_WRITE_DATA
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• FILE_APPEND_DATA
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• FILE_EXECUTE
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• WRITE_DAC_ACCESS
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• WRITE_OWNER_ACCESS
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• SEC_FLAG_SYSTEM_SECURITY
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• READ_CONTROL_ACCESS
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In the future we can remove the following rights from the list on systems
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that support O_PATH:
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• WRITE_DAC_ACCESS
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• WRITE_OWNER_ACCESS
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• SEC_FLAG_SYSTEM_SECURITY
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• READ_CONTROL_ACCESS
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1.2.4 Fallback on systems without O_PATH support
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╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌
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The code of higher level file-handle consumers must be kept simple and
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streamlined, avoiding special casing the handling of the file-handles
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opened with or without `O_PATH'. To achieve this, a fallback that allows
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opening a file-handle with the same higher level semantics even if the
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system doesn't support `O_PATH' is needed.
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The way this is implemented on such systems is impersonating the root user
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for the `open()' syscall. In order to avoid privelege escalations security
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issues, we must carefully control the use these file-handles.
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The low level filehandle is stored in a public struct `struct file_handle'
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that is part of the widely used `struct files_struct'. Consumers used to
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simply access the fd directly by derefencing pointers to `struct
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files_struct'.
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In order to guard access to such file-handles we do two things:
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• tag the pathref file-handles and
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• control access to the file-handle by making the structure `struct
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file_handle' private, only allowing access with accessor functions
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that implement a security boundary.
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In order to avoid bypassing restrictive permissions on intermediate
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directories of a client path, the root user is only impersonated after
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changing directory to the parent directory of the client requested
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pathname.
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Two functions can then be used to fetch the low-level system file-handle
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from a `struct files_struct':
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• `fsp_get_io_fd(fsp)': enforces fsp is NOT a pathref file-handle and
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• `fsp_get_pathref_fd(fsp)': allows fsp to be either a pathref file-handle
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or a traditional POSIX file-handle opened with O_RDONLY or any other
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POSIX open flag.
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Note that the name `fsp_get_pathref_fd()' may sound confusing at first
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given that the fsp can be either a pathref fsp or a "normal/full" fsp, but
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as any full file-handle can be used for IO and as path reference, the name
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correctly reflects the intended usage of the caller.
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1.2.5 When to use fsp_get_io_fd() or fsp_get_pathref_fd()
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╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌
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The general guideline is:
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• if you do something like `fstat(fd)', use `fsp_get_pathref_fd()',
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• if you do something like `*at(dirfd, ...)', use `fsp_get_pathref_fd()',
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• if you want to print the fd for example in `DEBUG' messages, use
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`fsp_get_pathref_fd()',
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• if you want to call `close(fd)', use `fsp_get_pathref_fd()',
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• if you're doing a logical comparison of fd values, use
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`fsp_get_pathref_fd()'.
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In any other case use `fsp_get_io_fd()'.
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2 VFS status quo and remaining work
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═══════════════════════════════════
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2.1 VFS Functions Tables [2]
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────────────────────────────
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2.1.1 Existing VFS Functions
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╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌
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━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
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VFS Function Group Status
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───────────────────────────────────────────────────────
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SMB_VFS_AIO_FORCE() [fsp] -
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SMB_VFS_AUDIT_FILE() [Special] -
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SMB_VFS_BRL_LOCK_WINDOWS() [fsp] -
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SMB_VFS_BRL_UNLOCK_WINDOWS() [fsp] -
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SMB_VFS_CHDIR() [Path] Todo
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SMB_VFS_CHFLAGS() [Path] Todo
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SMB_VFS_CHMOD() [Path] Todo
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SMB_VFS_CLOSE() [fsp] -
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SMB_VFS_CLOSEDIR() [fsp] -
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SMB_VFS_CONNECT() [Disk] -
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SMB_VFS_CONNECTPATH() [P2px] -
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SMB_VFS_CREATE_DFS_PATHAT() [NsC] Todo
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SMB_VFS_CREATE_FILE() [NsC] -
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SMB_VFS_DISCONNECT() [Disk] -
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SMB_VFS_DISK_FREE() [Disk] -
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SMB_VFS_DURABLE_COOKIE() [fsp] -
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SMB_VFS_DURABLE_DISCONNECT() [fsp] -
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SMB_VFS_DURABLE_RECONNECT() [fsp] -
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SMB_VFS_FALLOCATE() [fsp] -
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SMB_VFS_FCHMOD() [fsp] -
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SMB_VFS_FCHOWN() [fsp] -
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SMB_VFS_FCNTL() [fsp] -
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SMB_VFS_FDOPENDIR() [fsp] -
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SMB_VFS_FGET_COMPRESSION() [fsp] -
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SMB_VFS_FGET_DOS_ATTRIBUTES() [fsp] -
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SMB_VFS_FGET_NT_ACL() [fsp] -
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SMB_VFS_FGETXATTR() [xpathref] -
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SMB_VFS_FILE_ID_CREATE() [Special] -
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SMB_VFS_FLISTXATTR() [xpathref] -
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SMB_VFS_FREMOVEXATTR() [xpathref] -
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SMB_VFS_FS_CAPABILITIES() [Disk] -
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SMB_VFS_FSCTL() [fsp] -
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SMB_VFS_FSET_DOS_ATTRIBUTES() [fsp] -
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SMB_VFS_FSET_NT_ACL() [fsp] -
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SMB_VFS_FSETXATTR() [xpathref] -
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SMB_VFS_FS_FILE_ID() [Special] -
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SMB_VFS_FSTAT() [fsp] -
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SMB_VFS_FSYNC() [fsp] -
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SMB_VFS_FSYNC_SEND() [fsp] -
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SMB_VFS_FTRUNCATE() [fsp] -
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SMB_VFS_GET_ALLOC_SIZE() [fsp] -
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SMB_VFS_GET_DFS_REFERRALS() [Disk] -
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SMB_VFS_GET_DOS_ATTRIBUTES_RECV() [Enum] -
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SMB_VFS_GET_DOS_ATTRIBUTES_SEND() [Enum] -
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SMB_VFS_GETLOCK() [fsp] -
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SMB_VFS_GET_NT_ACL_AT() [Path] Todo
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SMB_VFS_GET_QUOTA() [Special] -
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SMB_VFS_GET_REAL_FILENAME() [P2px] -
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SMB_VFS_GET_SHADOW_COPY_DATA() [fsp] -
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SMB_VFS_GETWD() [Special] -
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SMB_VFS_GETXATTR() [Path] Todo
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SMB_VFS_GETXATTRAT_RECV() [Enum] -
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SMB_VFS_GETXATTRAT_SEND() [Enum] -
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SMB_VFS_KERNEL_FLOCK() [fsp] -
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SMB_VFS_LCHOWN() [Path] Todo
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SMB_VFS_LINKAT() [NsC] Todo
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SMB_VFS_LINUX_SETLEASE() [fsp] -
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SMB_VFS_LISTXATTR() [Path] Todo
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SMB_VFS_LOCK() [fsp] -
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SMB_VFS_LSEEK() [fsp] -
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SMB_VFS_LSTAT() [Path] Todo
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SMB_VFS_MKDIRAT() [NsC] Todo
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SMB_VFS_MKNODAT() [NsC] Todo
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SMB_VFS_NTIMES() [Path] Todo
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SMB_VFS_OFFLOAD_READ_RECV() [fsp] -
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SMB_VFS_OFFLOAD_READ_SEND() [fsp] -
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SMB_VFS_OFFLOAD_WRITE_RECV() [fsp] -
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SMB_VFS_OFFLOAD_WRITE_SEND() [fsp] -
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SMB_VFS_OPENAT() [NsC] -
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SMB_VFS_PREAD() [fsp] -
|
|||
|
SMB_VFS_PREAD_SEND() [fsp] -
|
|||
|
SMB_VFS_PWRITE() [fsp] -
|
|||
|
SMB_VFS_PWRITE_SEND() [fsp] -
|
|||
|
SMB_VFS_READ_DFS_PATHAT() [Symlink] Todo
|
|||
|
SMB_VFS_READDIR() [fsp] -
|
|||
|
SMB_VFS_READDIR_ATTR() [Path] Todo
|
|||
|
SMB_VFS_READLINKAT() [Symlink] Todo
|
|||
|
SMB_VFS_REALPATH() [P2px] -
|
|||
|
SMB_VFS_RECVFILE() [fsp] -
|
|||
|
SMB_VFS_REMOVEXATTR() [Path] Todo
|
|||
|
SMB_VFS_RENAMEAT() [Path] Todo
|
|||
|
SMB_VFS_REWINDDIR() [fsp] -
|
|||
|
SMB_VFS_SEEKDIR() [fsp] -
|
|||
|
SMB_VFS_SENDFILE() [fsp] -
|
|||
|
SMB_VFS_SET_COMPRESSION() [fsp] -
|
|||
|
SMB_VFS_SET_DOS_ATTRIBUTES() [Path] -
|
|||
|
SMB_VFS_SET_QUOTA() [Special] -
|
|||
|
SMB_VFS_SETXATTR() [Path] Todo
|
|||
|
SMB_VFS_SNAP_CHECK_PATH() [Disk] -
|
|||
|
SMB_VFS_SNAP_CREATE() [Disk] -
|
|||
|
SMB_VFS_SNAP_DELETE() [Disk] -
|
|||
|
SMB_VFS_STAT() [Path] Todo
|
|||
|
SMB_VFS_STATVFS() [Disk] -
|
|||
|
SMB_VFS_STREAMINFO() [Path] Todo
|
|||
|
SMB_VFS_STRICT_LOCK_CHECK() [fsp] -
|
|||
|
SMB_VFS_SYMLINKAT() [NsC] Todo
|
|||
|
SMB_VFS_SYS_ACL_BLOB_GET_FD() [xpathref] -
|
|||
|
SMB_VFS_SYS_ACL_BLOB_GET_FILE() [Path] Todo
|
|||
|
SMB_VFS_SYS_ACL_DELETE_DEF_FILE() [Path] Todo
|
|||
|
SMB_VFS_SYS_ACL_GET_FD() [xpathref] -
|
|||
|
SMB_VFS_SYS_ACL_GET_FILE() [Path] Todo
|
|||
|
SMB_VFS_SYS_ACL_SET_FD() [xpathref] -
|
|||
|
SMB_VFS_TELLDIR() [fsp] -
|
|||
|
SMB_VFS_TRANSLATE_NAME() [P2px] -
|
|||
|
SMB_VFS_UNLINKAT() [NsC] Todo
|
|||
|
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
|
|||
|
|
|||
|
|
|||
|
[fsp] See section 2.2.2
|
|||
|
|
|||
|
[Special] See section 2.2.9
|
|||
|
|
|||
|
[Path] See section 2.2.4
|
|||
|
|
|||
|
[Disk] See section 2.2.1
|
|||
|
|
|||
|
[P2px] See section 2.2.8
|
|||
|
|
|||
|
[NsC] See section 2.2.3
|
|||
|
|
|||
|
[xpathref] See section 2.2.7
|
|||
|
|
|||
|
[Enum] See section 2.2.6
|
|||
|
|
|||
|
[Symlink] See section 2.2.5
|
|||
|
|
|||
|
|
|||
|
2.1.2 New VFS Functions
|
|||
|
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌
|
|||
|
|
|||
|
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
|
|||
|
VFS Function Group Status
|
|||
|
─────────────────────────────────────────────────────
|
|||
|
SMB_VFS_SYS_ACL_DELETE_DEF_FD() [xpathref] Todo
|
|||
|
SMB_VFS_READDIR_ATTRAT() [Enum] Todo
|
|||
|
SMB_VFS_STATX() [Enum] Todo
|
|||
|
SMB_VFS_FUTIMENS() [fsp] Todo
|
|||
|
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
|
|||
|
|
|||
|
|
|||
|
[xpathref] See section 2.2.7
|
|||
|
|
|||
|
[Enum] See section 2.2.6
|
|||
|
|
|||
|
[fsp] See section 2.2.2
|
|||
|
|
|||
|
|
|||
|
2.2 VFS functions by category
|
|||
|
─────────────────────────────
|
|||
|
|
|||
|
2.2.1 Disk operations
|
|||
|
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌
|
|||
|
|
|||
|
• SMB_VFS_CONNECT()
|
|||
|
• SMB_VFS_DISCONNECT()
|
|||
|
• SMB_VFS_DISK_FREE()
|
|||
|
• SMB_VFS_FS_CAPABILITIES()
|
|||
|
• SMB_VFS_GET_DFS_REFERRALS()
|
|||
|
• SMB_VFS_SNAP_CHECK_PATH()
|
|||
|
• SMB_VFS_SNAP_CREATE()
|
|||
|
• SMB_VFS_SNAP_DELETE()
|
|||
|
• SMB_VFS_STATVFS()
|
|||
|
|
|||
|
No changes needed.
|
|||
|
|
|||
|
|
|||
|
2.2.2 Handle based VFS functions
|
|||
|
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌
|
|||
|
|
|||
|
• SMB_VFS_AIO_FORCE()
|
|||
|
• SMB_VFS_BRL_LOCK_WINDOWS()
|
|||
|
• SMB_VFS_BRL_UNLOCK_WINDOWS()
|
|||
|
• SMB_VFS_CLOSE()
|
|||
|
• SMB_VFS_CLOSEDIR()
|
|||
|
• SMB_VFS_DURABLE_COOKIE()
|
|||
|
• SMB_VFS_DURABLE_DISCONNECT()
|
|||
|
• SMB_VFS_FALLOCATE()
|
|||
|
• SMB_VFS_FCHMOD()
|
|||
|
• SMB_VFS_FCHOWN()
|
|||
|
• SMB_VFS_FCNTL()
|
|||
|
• SMB_VFS_FDOPENDIR()
|
|||
|
• SMB_VFS_FGET_DOS_ATTRIBUTES()
|
|||
|
• SMB_VFS_FGET_NT_ACL()
|
|||
|
• SMB_VFS_FSCTL()
|
|||
|
• SMB_VFS_FSET_DOS_ATTRIBUTES()
|
|||
|
• SMB_VFS_FSET_NT_ACL()
|
|||
|
• SMB_VFS_FSTAT()
|
|||
|
• SMB_VFS_FSYNC()
|
|||
|
• SMB_VFS_FSYNC_SEND()
|
|||
|
• SMB_VFS_FTRUNCATE()
|
|||
|
• SMB_VFS_GETLOCK()
|
|||
|
• SMB_VFS_GET_ALLOC_SIZE()
|
|||
|
• SMB_VFS_GET_SHADOW_COPY_DATA()
|
|||
|
• SMB_VFS_KERNEL_FLOCK()
|
|||
|
• SMB_VFS_LINUX_SETLEASE()
|
|||
|
• SMB_VFS_LOCK()
|
|||
|
• SMB_VFS_LSEEK()
|
|||
|
• SMB_VFS_OFFLOAD_READ_SEND()
|
|||
|
• SMB_VFS_OFFLOAD_WRITE_SEND()
|
|||
|
• SMB_VFS_PREAD()
|
|||
|
• SMB_VFS_PREAD_SEND()
|
|||
|
• SMB_VFS_PWRITE()
|
|||
|
• SMB_VFS_PWRITE_SEND()
|
|||
|
• SMB_VFS_READDIR()
|
|||
|
• SMB_VFS_RECVFILE()
|
|||
|
• SMB_VFS_REWINDDIR()
|
|||
|
• SMB_VFS_SEEKDIR()
|
|||
|
• SMB_VFS_SENDFILE()
|
|||
|
• SMB_VFS_SET_COMPRESSION()
|
|||
|
• SMB_VFS_STRICT_LOCK_CHECK()
|
|||
|
• SMB_VFS_TELLDIR()
|
|||
|
|
|||
|
If an fsp is provided by the SMB layer we use that, otherwise we use the
|
|||
|
pathref fsp `smb_fname->fsp' provided by `filename_convert()'.
|
|||
|
|
|||
|
|
|||
|
2.2.3 Namespace changing VFS functions
|
|||
|
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌
|
|||
|
|
|||
|
• SMB_VFS_CREATE_FILE()
|
|||
|
|
|||
|
All intermediate VFS calls within `SMB_VFS_CREATE_FILE()' will be based on
|
|||
|
`smb_fname->fsp' if the requested path exists. When creating a file we
|
|||
|
rely on `non_widelink_open()' which doesn't depend on a dirfsp.
|
|||
|
|
|||
|
• SMB_VFS_MKDIRAT()
|
|||
|
|
|||
|
Needs a real dirfsp (done).
|
|||
|
|
|||
|
• SMB_VFS_OPENAT()
|
|||
|
|
|||
|
Is only called from within `non_widelink_open()' with a dirfsp equivalent
|
|||
|
of `AT_FDCWD' and so doesn't need a real dirfsp.
|
|||
|
|
|||
|
The following operations need a real dirfsp:
|
|||
|
|
|||
|
• SMB_VFS_LINKAT()
|
|||
|
• SMB_VFS_MKNODAT()
|
|||
|
• SMB_VFS_RENAMEAT()
|
|||
|
• SMB_VFS_SYMLINKAT()
|
|||
|
• SMB_VFS_UNLINKAT()
|
|||
|
|
|||
|
Callers use `openat_pathref_fsp()' to open a fsp on the parent directory.
|
|||
|
|
|||
|
|
|||
|
2.2.4 Path based VFS functions
|
|||
|
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌
|
|||
|
|
|||
|
All path based VFS functtions will be replaced by handle based variants
|
|||
|
using the `smb_fname->fsp' provided by `filename_convert()'.
|
|||
|
|
|||
|
• SMB_VFS_CHDIR()
|
|||
|
• SMB_VFS_CHFLAGS()
|
|||
|
• SMB_VFS_CHMOD()
|
|||
|
• SMB_VFS_DURABLE_RECONNECT()
|
|||
|
• SMB_VFS_GETXATTR()
|
|||
|
• SMB_VFS_GET_COMPRESSION()
|
|||
|
• SMB_VFS_GET_DOS_ATTRIBUTES()
|
|||
|
• SMB_VFS_GET_NT_ACL_AT()
|
|||
|
• SMB_VFS_LCHOWN()
|
|||
|
• SMB_VFS_LISTXATTR()
|
|||
|
• SMB_VFS_LSTAT()
|
|||
|
• SMB_VFS_NTIMES()
|
|||
|
• SMB_VFS_REMOVEXATTR()
|
|||
|
• SMB_VFS_SETXATTR()
|
|||
|
• SMB_VFS_SET_DOS_ATTRIBUTES()
|
|||
|
• SMB_VFS_STAT()
|
|||
|
• SMB_VFS_STREAMINFO()
|
|||
|
• SMB_VFS_SYS_ACL_BLOB_GET_FILE()
|
|||
|
• SMB_VFS_SYS_ACL_DELETE_DEF_FILE()
|
|||
|
• SMB_VFS_SYS_ACL_GET_FILE()
|
|||
|
• SMB_VFS_SYS_ACL_SET_FILE()
|
|||
|
|
|||
|
Replace with corresponding handle based VFS calls.
|
|||
|
|
|||
|
|
|||
|
2.2.5 AT VFS functions that can't be based on handles
|
|||
|
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌
|
|||
|
|
|||
|
• SMB_VFS_CREATE_DFS_PATHAT()
|
|||
|
• SMB_VFS_READ_DFS_PATHAT()
|
|||
|
• SMB_VFS_READLINKAT()
|
|||
|
|
|||
|
As the DFS link implementation is based on symlinks, we have to use *AT
|
|||
|
based functions with real dirfsps.
|
|||
|
|
|||
|
|
|||
|
2.2.6 AT VFS functions needed for directory enumeration
|
|||
|
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌
|
|||
|
|
|||
|
• SMB_VFS_GET_DOS_ATTRIBUTES_SEND()
|
|||
|
• SMB_VFS_GETXATTRAT_SEND()
|
|||
|
• SMB_VFS_READDIR_ATTRAT() (NEW)
|
|||
|
• SMB_VFS_STATX() (NEW)
|
|||
|
|
|||
|
We can't open file-handles on all directory children for performance
|
|||
|
reasons. Therefor we need *AT based VFS functions for all metadata VFS
|
|||
|
queries done in the directory enumeration loop.
|
|||
|
|
|||
|
|
|||
|
2.2.7 Handle based VFS functions not allowed on O_PATH opened handles
|
|||
|
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌
|
|||
|
|
|||
|
• SMB_VFS_FGETXATTR()
|
|||
|
• SMB_VFS_FLISTXATTR()
|
|||
|
• SMB_VFS_FREMOVEXATTR()
|
|||
|
• SMB_VFS_FSETXATTR()
|
|||
|
• SMB_VFS_SYS_ACL_BLOB_GET_FD()
|
|||
|
• SMB_VFS_SYS_ACL_GET_FD()
|
|||
|
• SMB_VFS_SYS_ACL_DELETE_DEF_FD() (NEW)
|
|||
|
• SMB_VFS_SYS_ACL_SET_FD()
|
|||
|
|
|||
|
Based upon securely opening a full fd based on `/proc/self/fd/%d' as in
|
|||
|
the case of xattrs, pathref handles can't be used for xattr IO, and in the
|
|||
|
case of ACLs pathref handles can't be used to access default ACEs.
|
|||
|
|
|||
|
|
|||
|
2.2.8 Pure path to path translation
|
|||
|
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌
|
|||
|
|
|||
|
• SMB_VFS_CONNECTPATH()
|
|||
|
• SMB_VFS_GET_REAL_FILENAME()
|
|||
|
• SMB_VFS_REALPATH()
|
|||
|
• SMB_VFS_TRANSLATE_NAME()
|
|||
|
|
|||
|
No changes needed.
|
|||
|
|
|||
|
|
|||
|
2.2.9 Special cases
|
|||
|
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌
|
|||
|
|
|||
|
• SMB_VFS_FILE_ID_CREATE()
|
|||
|
• SMB_VFS_FS_FILE_ID()
|
|||
|
• SMB_VFS_GET_QUOTA()
|
|||
|
• SMB_VFS_GETWD()
|
|||
|
• SMB_VFS_SET_QUOTA()
|
|||
|
|
|||
|
No changes needed.
|
|||
|
|
|||
|
• SMB_VFS_AUDIT_FILE()
|
|||
|
|
|||
|
This is currently unused.
|
|||
|
|
|||
|
|
|||
|
|
|||
|
Footnotes
|
|||
|
─────────
|
|||
|
|
|||
|
[1] parts of the following sections copied from man open(2)
|
|||
|
|
|||
|
[2] `grep 'SMB_VFS_*' source3/include/vfs_macros.h | grep -v NEXT_ | sed
|
|||
|
's|.*\(SMB_VFS_.*\)(.*|\1()|' | sort'
|