PROTOCOLS

AdvisoryLocking

Defined in fuchsia.io/locking.fidl

Advisory locking protocol.

This protocol is intended to be composed into the |File| protocol to provide support for advisory locking.

Advisory locks are purely advisory. They do not prevent actual read or write operations from occurring on the file, either through this connection or through other connections.

These primitives are designed to support the flock() and fcntl(), specifically F_SETLK, F_SETLKW, and F_GETLK, functionality that code running on Fuchsia expects from other operating systems.

AdvisoryLock

Acquires an advisory lock on the underlying file.

The lock lasts until either this connection is closed or this method is called with |AdvisoryLockType.UNLOCK| to release the lock explicitly.

Advisory locks are purely advisory. They do not prevent actual read or write operations from occurring on the file, either through this connection or through other connections.

This method requires the following rights:

• Rights.READ_BYTES if request.type is AdvisoryLockType.READ.
• Rights.WRITE_BYTES if request.type is AdvisoryLockType.WRITE.

Errors

• ZX_ERR_BAD_STATE The specified type of lock cannot be acquired. For example, another connection might hold a conflicting lock type.
• ZX_ERR_NOT_SUPPORTED This file does not support advisory locking.
• ZX_ERR_ACCESS_DENIED This connection does not have sufficient rights to acquire the given type of lock.

Request

Response

Directory

Defined in fuchsia.io/directory.fidl

AddInotifyFilter

Adds a new inotify filter for an object relative to this directory object.

• 'filter` is a mask of different inotify events that need to be watched by the server for a specific file/directory.

• path may contain multiple segments, separated by "/" characters, and should never be empty; i.e., "" is an invalid path. Paths should not contain a leading "/".

+watch_descriptor is client assigned value to identify a filter. Server shouldn't trust the client-assigned watch_descriptor. They should just send it back to the client in the socket. This value is not used by server, but it is returned back as part of InotifyEvent, to help the client correlate filter with events on this filter.

• socket is shared between different filter objects i.e every new filter will have a different server end of the socket and there will be a single client end per inotify instance on inotify init.

Request

Response

<EMPTY>

AdvisoryLock

Acquires an advisory lock on the underlying file.

The lock lasts until either this connection is closed or this method is called with |AdvisoryLockType.UNLOCK| to release the lock explicitly.

Advisory locks are purely advisory. They do not prevent actual read or write operations from occurring on the file, either through this connection or through other connections.

This method requires the following rights:

• Rights.READ_BYTES if request.type is AdvisoryLockType.READ.
• Rights.WRITE_BYTES if request.type is AdvisoryLockType.WRITE.

Errors

• ZX_ERR_BAD_STATE The specified type of lock cannot be acquired. For example, another connection might hold a conflicting lock type.
• ZX_ERR_NOT_SUPPORTED This file does not support advisory locking.
• ZX_ERR_ACCESS_DENIED This connection does not have sufficient rights to acquire the given type of lock.

Request

Response

Clone

Create another connection to the same remote object.

flags may be any of:

• OpenFlags.RIGHT_*
• OpenFlags.APPEND
• OpenFlags.DESCRIBE
• OpenFlags.CLONE_SAME_RIGHTS

All other flags are ignored.

The OpenFlags.RIGHT_* bits in flags request corresponding rights over the resulting cloned object. The cloned object must have rights less than or equal to the original object, otherwise returns ZX_ERR_ACCESS_DENIED. Alternatively, pass OpenFlags.CLONE_SAME_RIGHTS to inherit the rights on the source connection. It is invalid to pass any of the OpenFlags.RIGHT_* flags together with OpenFlags.CLONE_SAME_RIGHTS.

Request

Close

Terminates the connection.

After calling Close, the client must not send any other requests.

Servers, after sending the status response, should close the connection regardless of status and without sending an epitaph.

Closing the client end of the channel should be semantically equivalent to calling Close without knowing when the close has completed or its status.

Request

<EMPTY>

Response

Enumerate

Initiates a directory listing operation over the input channel, starting at seek offset 0.

This method requires the Rights.ENUMERATE right. If this right is absent, iterator will be closed with a ZX_ERR_ACCESS_DENIED epitaph.

Request

GetAttr

Acquires information about the node.

This method does not require any rights.

Request

<EMPTY>

Response

GetAttributes

Acquires information about the node.

The attributes of a node should be stable, independent of the specific protocol used to access it.

If a particular attribute is not applicable or not supported, filesystems should leave the corresponding field absent.

• query a bit-mask specifying which attributes to fetch. The server should not return more than necessary.

• attributes the returned attributes.

This method requires the Rights.GET_ATTRIBUTES right.

Request

Response

GetConnectionInfo

Acquires information about the connection.

This method does not require any rights.

Request

<EMPTY>

Response

GetFlags

Acquires the Directory.Open rights and flags used to access this file.

This method does not require any rights.

Request

<EMPTY>

Response

GetToken

Acquires a token to a Directory which can be used to identify access to it at a later point in time. The token will remain valid for as long as the connection requesting the token remains open.

This method requires following rights: OpenFlags.RIGHT_WRITABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

<EMPTY>

Response

Link

Creates a link to an object named src by the name dst, within a directory represented by token.

src must be a resolved object name. Including "/" in the string will return ZX_ERR_INVALID_ARGS.

dst must be a resolved object name. Including "/" in the string will return ZX_ERR_INVALID_ARGS.

This method requires following rights: OpenFlags.RIGHT_WRITABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

Response

OnOpen

An event produced eagerly by a FIDL server if requested by OpenFlags.DESCRIBE.

Indicates the success or failure of the open operation, and optionally describes the object. If the status is ZX_OK, info contains descriptive information about the object (the same as would be returned by Describe).

Response

OnRepresentation

An event produced eagerly by the server if requested by NodeFlags.GET_REPRESENTATION. This event will be the first message from the server, and is sent exactly once.

The active variant corresponds to one of the supported protocols of the node, and represents the result of the connection-time negotiation. Provides auxiliary handles if applicable.

If the client specified more than one protocol in protocols during Directory.Open, the Representation carries additionally the result of the connection-time negotiation via its tag.

The elements have one-to-one correspondence with the members of NodeProtocolKinds.

This is a special case of fuchsia.unknown/Queryable.Query + inherent Describe methods on the specific protocols. It exists as an optimization to avoid an additional round trip.

Response

Open

Opens a new object relative to this directory object.

path may contain multiple segments, separated by "/" characters, and should never be empty; i.e. "" is an invalid path. A trailing slash implies OpenFlags.DIRECTORY. Components must not be empty (i.e. "foo//bar" is invalid). ".." is disallowed anywhere in the path. "." is only allowed if the path is exactly ".", but not otherwise. A leading '/' is allowed (and is treated the same way as if not present, i.e. "/foo/bar' and "foo/bar" are the same).

If an unknown value is sent for flags the connection should be closed.

OpenFlags.RIGHT_* flags provided in flags will restrict access rights on the object channel which will be connected to the opened entity.

Rights are never increased. When you open a nested entity within a directory, you may only request the same rights as what the directory connection already has, or a subset of those. Exceeding those rights causes an access denied error to be transmitted in the OnOpen event if applicable, and the object connection closed.

mode is only used if an object is created and indicates the type of object to be created. An unsupported mode will cause the connection to be closed. The mode type, if set, must always be consistent with the OpenFlags.DIRECTORY and OpenFlags.NOT_DIRECTORY flags, even if an object is not being created. If an object is not being created, mode is otherwise ignored. If an object is being created and the mode type is not set, a directory will be created if OpenFlags.DIRECTORY is set (explicitly or implicitly), or otherwise a server chosen object type.

Request

Open2

Opens or creates a new node relative to this directory node.

This method requires the following rights on the current connection:

• Rights.ENUMERATE
• Rights.TRAVERSE

Errors are presented as an epitaph on the object_request channel.

• error ZX_ERR_ACCESS_DENIED if the requested rights exceeds what is allowed.
• error ZX_ERR_BAD_PATH if path is invalid.

Request

Query

Request

<EMPTY>

Response

QueryFilesystem

Query the filesystem for filesystem-specific information.

Request

<EMPTY>

Response

ReadDirents

Reads a collection of variably sized dirents into a buffer. The number of dirents in a directory may be very large: akin to calling read multiple times on a file, directories have a seek offset which is updated on subsequent calls to ReadDirents. Each call to ReadDirents will only return whole dirent structures, they will not get split across ReadDirent calls. When the seek offset reaches the end, dirents will be empty.

These dirents are of the form:

struct dirent {
  // Describes the inode of the entry.
  uint64 ino;
  // Describes the length of the dirent name in bytes.
  uint8 size;
  // Describes the type of the entry. Aligned with the
  // POSIX d_type values. Use `DirentType` constants.
  uint8 type;
  // Unterminated name of entry.
  char name[0];
}

This method does not require any rights, since one could always probe for directory contents by triggering name conflicts during file creation.

Request

Response

Rename

Renames a node named src to the name dst, in a directory represented by dst_parent_token.

src and dst must be valid node names. See Name for what constitutes a valid name.

This method requires the following rights on both the current connection, and the connection identified by dst_parent_token:

• Rights.ENUMERATE

• Rights.MODIFY_DIRECTORY

• error ZX_ERR_INVALID_ARGS if src or dst is invalid.

Request

Response

Reopen

Creates another connection to the same node.

• object_request is the server end of a channel created for the new connection. The caller may proceed to send messages on the corresponding client end right away.

Request

Rewind

Resets the directory seek offset.

This method does not require any rights, similar to ReadDirents.

Request

<EMPTY>

Response

SetAttr

Updates information about the node.

This method requires following rights: OpenFlags.RIGHT_WRITABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

Response

SetFlags

Changes the Directory.Open flags used to access the file. Supported flags which can be turned on / off:

• OpenFlags.APPEND

This method does not require any rights.

Request

Response

Sync

Synchronizes updates to the node to the underlying media, if it exists.

This method will return when the filesystem server has flushed the relevant updates to the underlying media, but does not guarantee the underlying media has persisted the information, nor that any information is committed to hardware. Clients may use Sync to ensure ordering between operations.

This method does not require any rights.

Request

<EMPTY>

Response

Unlink

Removes a child node from the this directory's list of entries.

Note: this does not guarantee that the underlying object is destroyed. Although the link will be removed from the containing directory, objects with multiple references (such as files which are still open) will not actually be destroyed until all references are closed.

• error ZX_ERR_ACCESS_DENIED if the connection does not have Rights.WRITE_BYTES.
• error ZX_ERR_NOT_SUPPORTED if the underlying filesystem does not support writing.
• error ZX_ERR_BAD_PATH if name is invalid.
• error ZX_ERR_NOT_EMPTY if name refers to a non-empty directory.
• error ZX_ERR_UNAVAILABLE if name refers to a mount point, containing a remote channel.
• error ZX_ERR_NOT_DIR if the options requested a directory but something other than a directory was found.

Other errors may be returned for filesystem-specific reasons.

This method requires the following rights:

• Rights.ENUMERATE
• Rights.MODIFY_DIRECTORY

Request

Response

UpdateAttributes

Updates information about the node.

• attributes the presence of a table field in attributes indicates the intent to update the corresponding attribute.

This method requires the Rights.UPDATE_ATTRIBUTES right.

Request

Response

Watch

Watches a directory, receiving events of added messages on the watcher request channel.

Options must be zero; it is reserved.

This method does not require any rights, similar to ReadDirents.

Request

Response

Directory1

Defined in fuchsia.io/directory.fidl

Directory defines a node which is capable of containing other Objects.

Clone

Create another connection to the same remote object.

flags may be any of:

• OpenFlags.RIGHT_*
• OpenFlags.APPEND
• OpenFlags.DESCRIBE
• OpenFlags.CLONE_SAME_RIGHTS

All other flags are ignored.

The OpenFlags.RIGHT_* bits in flags request corresponding rights over the resulting cloned object. The cloned object must have rights less than or equal to the original object, otherwise returns ZX_ERR_ACCESS_DENIED. Alternatively, pass OpenFlags.CLONE_SAME_RIGHTS to inherit the rights on the source connection. It is invalid to pass any of the OpenFlags.RIGHT_* flags together with OpenFlags.CLONE_SAME_RIGHTS.

Request

GetAttr

Acquires information about the node.

This method does not require any rights.

Request

<EMPTY>

Response

GetFlags

Acquires the Directory.Open rights and flags used to access this file.

This method does not require any rights.

Request

<EMPTY>

Response

GetToken

Acquires a token to a Directory which can be used to identify access to it at a later point in time. The token will remain valid for as long as the connection requesting the token remains open.

This method requires following rights: OpenFlags.RIGHT_WRITABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

<EMPTY>

Response

Link

Creates a link to an object named src by the name dst, within a directory represented by token.

src must be a resolved object name. Including "/" in the string will return ZX_ERR_INVALID_ARGS.

dst must be a resolved object name. Including "/" in the string will return ZX_ERR_INVALID_ARGS.

This method requires following rights: OpenFlags.RIGHT_WRITABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

Response

OnOpen

An event produced eagerly by a FIDL server if requested by OpenFlags.DESCRIBE.

Indicates the success or failure of the open operation, and optionally describes the object. If the status is ZX_OK, info contains descriptive information about the object (the same as would be returned by Describe).

Response

Open

Opens a new object relative to this directory object.

path may contain multiple segments, separated by "/" characters, and should never be empty; i.e. "" is an invalid path. A trailing slash implies OpenFlags.DIRECTORY. Components must not be empty (i.e. "foo//bar" is invalid). ".." is disallowed anywhere in the path. "." is only allowed if the path is exactly ".", but not otherwise. A leading '/' is allowed (and is treated the same way as if not present, i.e. "/foo/bar' and "foo/bar" are the same).

If an unknown value is sent for flags the connection should be closed.

OpenFlags.RIGHT_* flags provided in flags will restrict access rights on the object channel which will be connected to the opened entity.

Rights are never increased. When you open a nested entity within a directory, you may only request the same rights as what the directory connection already has, or a subset of those. Exceeding those rights causes an access denied error to be transmitted in the OnOpen event if applicable, and the object connection closed.

mode is only used if an object is created and indicates the type of object to be created. An unsupported mode will cause the connection to be closed. The mode type, if set, must always be consistent with the OpenFlags.DIRECTORY and OpenFlags.NOT_DIRECTORY flags, even if an object is not being created. If an object is not being created, mode is otherwise ignored. If an object is being created and the mode type is not set, a directory will be created if OpenFlags.DIRECTORY is set (explicitly or implicitly), or otherwise a server chosen object type.

Request

QueryFilesystem

Query the filesystem for filesystem-specific information.

Request

<EMPTY>

Response

ReadDirents

Reads a collection of variably sized dirents into a buffer. The number of dirents in a directory may be very large: akin to calling read multiple times on a file, directories have a seek offset which is updated on subsequent calls to ReadDirents. Each call to ReadDirents will only return whole dirent structures, they will not get split across ReadDirent calls. When the seek offset reaches the end, dirents will be empty.

These dirents are of the form:

struct dirent {
  // Describes the inode of the entry.
  uint64 ino;
  // Describes the length of the dirent name in bytes.
  uint8 size;
  // Describes the type of the entry. Aligned with the
  // POSIX d_type values. Use `DirentType` constants.
  uint8 type;
  // Unterminated name of entry.
  char name[0];
}

This method does not require any rights, since one could always probe for directory contents by triggering name conflicts during file creation.

Request

Response

Rewind

Resets the directory seek offset.

This method does not require any rights, similar to ReadDirents.

Request

<EMPTY>

Response

SetAttr

Updates information about the node.

This method requires following rights: OpenFlags.RIGHT_WRITABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

Response

SetFlags

Changes the Directory.Open flags used to access the file. Supported flags which can be turned on / off:

• OpenFlags.APPEND

This method does not require any rights.

Request

Response

Watch

Watches a directory, receiving events of added messages on the watcher request channel.

Options must be zero; it is reserved.

This method does not require any rights, similar to ReadDirents.

Request

Response

Directory2

Defined in fuchsia.io/directory2.fidl

A Node2 that is capable of containing other nodes.

AddInotifyFilter

Adds a new inotify filter for an object relative to this directory object.

• 'filter` is a mask of different inotify events that need to be watched by the server for a specific file/directory.

• path may contain multiple segments, separated by "/" characters, and should never be empty; i.e., "" is an invalid path. Paths should not contain a leading "/".

+watch_descriptor is client assigned value to identify a filter. Server shouldn't trust the client-assigned watch_descriptor. They should just send it back to the client in the socket. This value is not used by server, but it is returned back as part of InotifyEvent, to help the client correlate filter with events on this filter.

• socket is shared between different filter objects i.e every new filter will have a different server end of the socket and there will be a single client end per inotify instance on inotify init.

Request

Response

<EMPTY>

AdvisoryLock

Acquires an advisory lock on the underlying file.

The lock lasts until either this connection is closed or this method is called with |AdvisoryLockType.UNLOCK| to release the lock explicitly.

Advisory locks are purely advisory. They do not prevent actual read or write operations from occurring on the file, either through this connection or through other connections.

This method requires the following rights:

• Rights.READ_BYTES if request.type is AdvisoryLockType.READ.
• Rights.WRITE_BYTES if request.type is AdvisoryLockType.WRITE.

Errors

• ZX_ERR_BAD_STATE The specified type of lock cannot be acquired. For example, another connection might hold a conflicting lock type.
• ZX_ERR_NOT_SUPPORTED This file does not support advisory locking.
• ZX_ERR_ACCESS_DENIED This connection does not have sufficient rights to acquire the given type of lock.

Request

Response

Close

Terminates the connection.

After calling Close, the client must not send any other requests.

Servers, after sending the status response, should close the connection regardless of status and without sending an epitaph.

Closing the client end of the channel should be semantically equivalent to calling Close without knowing when the close has completed or its status.

Request

<EMPTY>

Response

Enumerate

Initiates a directory listing operation over the input channel, starting at seek offset 0.

This method requires the Rights.ENUMERATE right. If this right is absent, iterator will be closed with a ZX_ERR_ACCESS_DENIED epitaph.

Request

GetAttributes

Acquires information about the node.

The attributes of a node should be stable, independent of the specific protocol used to access it.

If a particular attribute is not applicable or not supported, filesystems should leave the corresponding field absent.

• query a bit-mask specifying which attributes to fetch. The server should not return more than necessary.

• attributes the returned attributes.

This method requires the Rights.GET_ATTRIBUTES right.

Request

Response

GetConnectionInfo

Acquires information about the connection.

This method does not require any rights.

Request

<EMPTY>

Response

OnRepresentation

An event produced eagerly by the server if requested by NodeFlags.GET_REPRESENTATION. This event will be the first message from the server, and is sent exactly once.

The active variant corresponds to one of the supported protocols of the node, and represents the result of the connection-time negotiation. Provides auxiliary handles if applicable.

If the client specified more than one protocol in protocols during Directory.Open, the Representation carries additionally the result of the connection-time negotiation via its tag.

The elements have one-to-one correspondence with the members of NodeProtocolKinds.

This is a special case of fuchsia.unknown/Queryable.Query + inherent Describe methods on the specific protocols. It exists as an optimization to avoid an additional round trip.

Response

Open2

Opens or creates a new node relative to this directory node.

This method requires the following rights on the current connection:

• Rights.ENUMERATE
• Rights.TRAVERSE

Errors are presented as an epitaph on the object_request channel.

• error ZX_ERR_ACCESS_DENIED if the requested rights exceeds what is allowed.
• error ZX_ERR_BAD_PATH if path is invalid.

Request

Query

Request

<EMPTY>

Response

Rename

Renames a node named src to the name dst, in a directory represented by dst_parent_token.

src and dst must be valid node names. See Name for what constitutes a valid name.

This method requires the following rights on both the current connection, and the connection identified by dst_parent_token:

• Rights.ENUMERATE

• Rights.MODIFY_DIRECTORY

• error ZX_ERR_INVALID_ARGS if src or dst is invalid.

Request

Response

Reopen

Creates another connection to the same node.

• object_request is the server end of a channel created for the new connection. The caller may proceed to send messages on the corresponding client end right away.

Request

Sync

Synchronizes updates to the node to the underlying media, if it exists.

This method will return when the filesystem server has flushed the relevant updates to the underlying media, but does not guarantee the underlying media has persisted the information, nor that any information is committed to hardware. Clients may use Sync to ensure ordering between operations.

This method does not require any rights.

Request

<EMPTY>

Response

Unlink

Removes a child node from the this directory's list of entries.

Note: this does not guarantee that the underlying object is destroyed. Although the link will be removed from the containing directory, objects with multiple references (such as files which are still open) will not actually be destroyed until all references are closed.

• error ZX_ERR_ACCESS_DENIED if the connection does not have Rights.WRITE_BYTES.
• error ZX_ERR_NOT_SUPPORTED if the underlying filesystem does not support writing.
• error ZX_ERR_BAD_PATH if name is invalid.
• error ZX_ERR_NOT_EMPTY if name refers to a non-empty directory.
• error ZX_ERR_UNAVAILABLE if name refers to a mount point, containing a remote channel.
• error ZX_ERR_NOT_DIR if the options requested a directory but something other than a directory was found.

Other errors may be returned for filesystem-specific reasons.

This method requires the following rights:

• Rights.ENUMERATE
• Rights.MODIFY_DIRECTORY

Request

Response

UpdateAttributes

Updates information about the node.

• attributes the presence of a table field in attributes indicates the intent to update the corresponding attribute.

This method requires the Rights.UPDATE_ATTRIBUTES right.

Request

Response

DirectoryIterator

Defined in fuchsia.io/directory2.fidl

GetNext

Reads a collection of variably sized directory entries into a buffer.

The number of entries in a directory may be very large: akin to calling read multiple times on a file, directories have a seek offset which is updated on subsequent calls to Enumerate. The caller should always use a receiving buffer size as large as the maximum channel limit.

When the end of iteration is reached, the returned entries vector will be empty.

This method does not require any rights, as the rights are checked in the Directory.Enumerate call.

Request

<EMPTY>

Response

DirectoryWatcher

Defined in fuchsia.io/directory.fidl

DirectoryWatcher transmits messages from a filesystem server about events happening in the filesystem. Clients can register new watchers using the Directory.Watch method, where they can filter which events they want to receive notifications for.

The DirectoryWatcher will send messages of the form:

struct {
  uint8 event;
  uint8 len;
  char name[];
};

Where names are NOT null-terminated. The name is the relative path to the entry the event is refering to. It will be empty if the event isn't referencing a particular entry (e.g. for the IDLE event).

File

Defined in fuchsia.io/file2.fidl

A Node which contains a sequence of bytes of definite length.

NOTE: cloned connections do not share their seek offset with their source connection.

AdvisoryLock

Acquires an advisory lock on the underlying file.

The lock lasts until either this connection is closed or this method is called with |AdvisoryLockType.UNLOCK| to release the lock explicitly.

Advisory locks are purely advisory. They do not prevent actual read or write operations from occurring on the file, either through this connection or through other connections.

This method requires the following rights:

• Rights.READ_BYTES if request.type is AdvisoryLockType.READ.
• Rights.WRITE_BYTES if request.type is AdvisoryLockType.WRITE.

Errors

• ZX_ERR_BAD_STATE The specified type of lock cannot be acquired. For example, another connection might hold a conflicting lock type.
• ZX_ERR_NOT_SUPPORTED This file does not support advisory locking.
• ZX_ERR_ACCESS_DENIED This connection does not have sufficient rights to acquire the given type of lock.

Request

Response

Clone

Create another connection to the same remote object.

flags may be any of:

• OpenFlags.RIGHT_*
• OpenFlags.APPEND
• OpenFlags.DESCRIBE
• OpenFlags.CLONE_SAME_RIGHTS

All other flags are ignored.

The OpenFlags.RIGHT_* bits in flags request corresponding rights over the resulting cloned object. The cloned object must have rights less than or equal to the original object, otherwise returns ZX_ERR_ACCESS_DENIED. Alternatively, pass OpenFlags.CLONE_SAME_RIGHTS to inherit the rights on the source connection. It is invalid to pass any of the OpenFlags.RIGHT_* flags together with OpenFlags.CLONE_SAME_RIGHTS.

Request

Close

Terminates the connection.

After calling Close, the client must not send any other requests.

Servers, after sending the status response, should close the connection regardless of status and without sending an epitaph.

Closing the client end of the channel should be semantically equivalent to calling Close without knowing when the close has completed or its status.

Request

<EMPTY>

Response

Describe

Request

<EMPTY>

Response

GetAttr

Acquires information about the node.

This method does not require any rights.

Request

<EMPTY>

Response

GetAttributes

Acquires information about the node.

The attributes of a node should be stable, independent of the specific protocol used to access it.

If a particular attribute is not applicable or not supported, filesystems should leave the corresponding field absent.

• query a bit-mask specifying which attributes to fetch. The server should not return more than necessary.

• attributes the returned attributes.

This method requires the Rights.GET_ATTRIBUTES right.

Request

Response

GetBackingMemory

Acquires a zx.handle:VMO representing this file, if there is one, with the requested access rights.

Implementations are not required to implement files backed by VMOs so this request may fail. Additionally, implementations may only support a certain subset of the flags. Clients should be prepared with fallback behavior if this request fails.

If a client specifies neither PRIVATE_CLONE nor SHARED_BUFFER, the implementation is free to choose the semantics of the returned VMO.

• request flags a VmoFlags indicating the desired mode of access.

• response vmo the requested zx.handle:VMO.

• error a zx.status value indicating the failure.

This method requires the following rights:

• Rights.READ_BYTES if flags includes VmoFlags.READ.
• Rights.WRITE_BYTES if flags includes VmoFlags.WRITE.
• Rights.EXECUTE if flags includes VmoFlags.EXECUTE.

Request

Response

GetConnectionInfo

Acquires information about the connection.

This method does not require any rights.

Request

<EMPTY>

Response

GetFlags

Acquires the Directory.Open rights and flags used to access this file.

This method does not require any rights.

Request

<EMPTY>

Response

OnOpen

An event produced eagerly by a FIDL server if requested by OpenFlags.DESCRIBE.

Indicates the success or failure of the open operation, and optionally describes the object. If the status is ZX_OK, info contains descriptive information about the object (the same as would be returned by Describe).

Response

OnRepresentation

An event produced eagerly by the server if requested by NodeFlags.GET_REPRESENTATION. This event will be the first message from the server, and is sent exactly once.

The active variant corresponds to one of the supported protocols of the node, and represents the result of the connection-time negotiation. Provides auxiliary handles if applicable.

If the client specified more than one protocol in protocols during Directory.Open, the Representation carries additionally the result of the connection-time negotiation via its tag.

The elements have one-to-one correspondence with the members of NodeProtocolKinds.

This is a special case of fuchsia.unknown/Queryable.Query + inherent Describe methods on the specific protocols. It exists as an optimization to avoid an additional round trip.

Response

Query

Request

<EMPTY>

Response

QueryFilesystem

Query the filesystem for filesystem-specific information.

Request

<EMPTY>

Response

Read

Reads up to 'count' bytes at the seek offset. The seek offset is moved forward by the number of bytes read.

Invariants

• The returned data.length will never be greater than count.
• If data.length is less than count, it means that the seek offset has reached the end of file as part of this operation.
• If data.length is zero while count is not, it means that the seek offset is already at or beyond the end of file, and no data could be read.
• If count is zero, the server should perform all the checks ensuring read access without actually read anything, and return an empty data vector.

This method requires the Rights.READ_BYTES right.

Returns ZX_ERR_OUT_OF_RANGE if count is greater than MAX_TRANSFER_SIZE.

Request

Response

ReadAt

Reads up to 'count' bytes at the provided offset. Does not affect the seek offset.

Invariants

• The returned data.length will never be greater than count.
• If data.length is less than count, it means that ReadAt has hit the end of file as part of this operation.
• If data.length is zero while count is not, it means that offset is at or past the end of file, and no data can be read.
• If count is zero, the server should perform all the checks ensuring read access without actually reading anything, and return an empty data vector.

This method requires the Rights.READ_BYTES right.

Returns ZX_ERR_OUT_OF_RANGE if count is greater than MAX_TRANSFER_SIZE.

Request

Response

Reopen

Creates another connection to the same node.

• object_request is the server end of a channel created for the new connection. The caller may proceed to send messages on the corresponding client end right away.

Request

Resize

Shrinks or grows the file size to 'length' bytes.

If file size is reduced by this operation, the extra trailing data' is discarded. If file size is increased by this operation, the extended area appears as if it was zeroed.

This method requires the Rights.WRITE_BYTES right.

Request

Response

Seek

Moves the offset at which the next invocation of Read or Write will occur. The seek offset is specific to each file connection.

• request origin the reference point where offset will be based on.
• request offset the number of bytes to seek.

• response offset_from_start the adjusted seek offset, from the start of the file.

This method does not require any rights.

Request

Response

SetAttr

Updates information about the node.

This method requires following rights: OpenFlags.RIGHT_WRITABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

Response

SetFlags

Changes the Directory.Open flags used to access the file. Supported flags which can be turned on / off:

• OpenFlags.APPEND

This method does not require any rights.

Request

Response

Sync

Synchronizes updates to the node to the underlying media, if it exists.

This method will return when the filesystem server has flushed the relevant updates to the underlying media, but does not guarantee the underlying media has persisted the information, nor that any information is committed to hardware. Clients may use Sync to ensure ordering between operations.

This method does not require any rights.

Request

<EMPTY>

Response

UpdateAttributes

Updates information about the node.

• attributes the presence of a table field in attributes indicates the intent to update the corresponding attribute.

This method requires the Rights.UPDATE_ATTRIBUTES right.

Request

Response

Write

Writes data at the seek offset. The seek offset is moved forward by the number of bytes written. If the file is in append mode, the seek offset is first set to the end of the file, followed by the write, in one atomic step.

The file size may grow if the seek offset plus data.length is beyond the current end of file.

• request data the byte buffer to write to the file.

• response actual_count the number of bytes written.

Invariants

• The returned actual_count will never be greater than data.length.
• If the server is unable to write all the data due to e.g. not enough space, actual_count may be less than data.length. If no bytes could be written, an error is returned.
• If data.length is zero, the server should perform all the checks ensuring write access without mutating the file and return a successful write of zero bytes. The seek offset is still updated if in append mode.

This method requires the Rights.WRITE_BYTES right.

Request

Response

WriteAt

Writes data at the provided offset. Does not affect the seek offset.

The file size may grow if offset plus data.length is past the current end of file.

• request data the byte buffer to write to the file.
• request offset the offset from start of the file to begin writing.

• response actual_count the number of bytes written.

Invariants

• The returned actual_count will never be greater than data.length.
• If the server is unable to write all the data due to e.g. not enough space, actual_count may be less than data.length. If no bytes could be written, an error is returned.
• If data.length is zero, the server should perform all the checks ensuring write access without mutating the file, and will return a successful write of zero bytes.

This method requires the Rights.WRITE_BYTES right.

Request

Response

Inotifier

Defined in fuchsia.io/inotify.fidl

Inotifier implements the linux Inotify functionality. It provides a mechanism for monitoring filesystem events. Inotify can be used to monitor individual files, or to monitor directories. When a directory is monitored, inotify will return events for the directory itself, and for files inside the directory.

Node

Defined in fuchsia.io/node.fidl

Clone

Create another connection to the same remote object.

flags may be any of:

• OpenFlags.RIGHT_*
• OpenFlags.APPEND
• OpenFlags.DESCRIBE
• OpenFlags.CLONE_SAME_RIGHTS

All other flags are ignored.

The OpenFlags.RIGHT_* bits in flags request corresponding rights over the resulting cloned object. The cloned object must have rights less than or equal to the original object, otherwise returns ZX_ERR_ACCESS_DENIED. Alternatively, pass OpenFlags.CLONE_SAME_RIGHTS to inherit the rights on the source connection. It is invalid to pass any of the OpenFlags.RIGHT_* flags together with OpenFlags.CLONE_SAME_RIGHTS.

Request

Close

Terminates the connection.

After calling Close, the client must not send any other requests.

Servers, after sending the status response, should close the connection regardless of status and without sending an epitaph.

Closing the client end of the channel should be semantically equivalent to calling Close without knowing when the close has completed or its status.

Request

<EMPTY>

Response

GetAttr

Acquires information about the node.

This method does not require any rights.

Request

<EMPTY>

Response

GetAttributes

Acquires information about the node.

The attributes of a node should be stable, independent of the specific protocol used to access it.

If a particular attribute is not applicable or not supported, filesystems should leave the corresponding field absent.

• query a bit-mask specifying which attributes to fetch. The server should not return more than necessary.

• attributes the returned attributes.

This method requires the Rights.GET_ATTRIBUTES right.

Request

Response

GetConnectionInfo

Acquires information about the connection.

This method does not require any rights.

Request

<EMPTY>

Response

GetFlags

Acquires the Directory.Open rights and flags used to access this file.

This method does not require any rights.

Request

<EMPTY>

Response

OnOpen

An event produced eagerly by a FIDL server if requested by OpenFlags.DESCRIBE.

Indicates the success or failure of the open operation, and optionally describes the object. If the status is ZX_OK, info contains descriptive information about the object (the same as would be returned by Describe).

Response

OnRepresentation

An event produced eagerly by the server if requested by NodeFlags.GET_REPRESENTATION. This event will be the first message from the server, and is sent exactly once.

The active variant corresponds to one of the supported protocols of the node, and represents the result of the connection-time negotiation. Provides auxiliary handles if applicable.

If the client specified more than one protocol in protocols during Directory.Open, the Representation carries additionally the result of the connection-time negotiation via its tag.

The elements have one-to-one correspondence with the members of NodeProtocolKinds.

This is a special case of fuchsia.unknown/Queryable.Query + inherent Describe methods on the specific protocols. It exists as an optimization to avoid an additional round trip.

Response

Query

Request

<EMPTY>

Response

QueryFilesystem

Query the filesystem for filesystem-specific information.

Request

<EMPTY>

Response

Reopen

Creates another connection to the same node.

• object_request is the server end of a channel created for the new connection. The caller may proceed to send messages on the corresponding client end right away.

Request

SetAttr

Updates information about the node.

This method requires following rights: OpenFlags.RIGHT_WRITABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

Response

SetFlags

Changes the Directory.Open flags used to access the file. Supported flags which can be turned on / off:

• OpenFlags.APPEND

This method does not require any rights.

Request

Response

Sync

Synchronizes updates to the node to the underlying media, if it exists.

This method will return when the filesystem server has flushed the relevant updates to the underlying media, but does not guarantee the underlying media has persisted the information, nor that any information is committed to hardware. Clients may use Sync to ensure ordering between operations.

This method does not require any rights.

Request

<EMPTY>

Response

UpdateAttributes

Updates information about the node.

• attributes the presence of a table field in attributes indicates the intent to update the corresponding attribute.

This method requires the Rights.UPDATE_ATTRIBUTES right.

Request

Response

Node1

Defined in fuchsia.io/node.fidl

Node defines the minimal interface for entities which can be accessed in a filesystem.

Clone

Create another connection to the same remote object.

flags may be any of:

• OpenFlags.RIGHT_*
• OpenFlags.APPEND
• OpenFlags.DESCRIBE
• OpenFlags.CLONE_SAME_RIGHTS

All other flags are ignored.

The OpenFlags.RIGHT_* bits in flags request corresponding rights over the resulting cloned object. The cloned object must have rights less than or equal to the original object, otherwise returns ZX_ERR_ACCESS_DENIED. Alternatively, pass OpenFlags.CLONE_SAME_RIGHTS to inherit the rights on the source connection. It is invalid to pass any of the OpenFlags.RIGHT_* flags together with OpenFlags.CLONE_SAME_RIGHTS.

Request

GetAttr

Acquires information about the node.

This method does not require any rights.

Request

<EMPTY>

Response

GetFlags

Acquires the Directory.Open rights and flags used to access this file.

This method does not require any rights.

Request

<EMPTY>

Response

OnOpen

An event produced eagerly by a FIDL server if requested by OpenFlags.DESCRIBE.

Indicates the success or failure of the open operation, and optionally describes the object. If the status is ZX_OK, info contains descriptive information about the object (the same as would be returned by Describe).

Response

QueryFilesystem

Query the filesystem for filesystem-specific information.

Request

<EMPTY>

Response

SetAttr

Updates information about the node.

This method requires following rights: OpenFlags.RIGHT_WRITABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

Response

SetFlags

Changes the Directory.Open flags used to access the file. Supported flags which can be turned on / off:

• OpenFlags.APPEND

This method does not require any rights.

Request

Response

Node2

Defined in fuchsia.io/node2.fidl

Node defines the minimal protocol for entities which can be accessed in a filesystem.

Close

Terminates the connection.

After calling Close, the client must not send any other requests.

Servers, after sending the status response, should close the connection regardless of status and without sending an epitaph.

Closing the client end of the channel should be semantically equivalent to calling Close without knowing when the close has completed or its status.

Request

<EMPTY>

Response

GetAttributes

Acquires information about the node.

The attributes of a node should be stable, independent of the specific protocol used to access it.

If a particular attribute is not applicable or not supported, filesystems should leave the corresponding field absent.

• query a bit-mask specifying which attributes to fetch. The server should not return more than necessary.

• attributes the returned attributes.

This method requires the Rights.GET_ATTRIBUTES right.

Request

Response

GetConnectionInfo

Acquires information about the connection.

This method does not require any rights.

Request

<EMPTY>

Response

OnRepresentation

An event produced eagerly by the server if requested by NodeFlags.GET_REPRESENTATION. This event will be the first message from the server, and is sent exactly once.

The active variant corresponds to one of the supported protocols of the node, and represents the result of the connection-time negotiation. Provides auxiliary handles if applicable.

If the client specified more than one protocol in protocols during Directory.Open, the Representation carries additionally the result of the connection-time negotiation via its tag.

The elements have one-to-one correspondence with the members of NodeProtocolKinds.

This is a special case of fuchsia.unknown/Queryable.Query + inherent Describe methods on the specific protocols. It exists as an optimization to avoid an additional round trip.

Response

Query

Request

<EMPTY>

Response

Reopen

Creates another connection to the same node.

• object_request is the server end of a channel created for the new connection. The caller may proceed to send messages on the corresponding client end right away.

Request

Sync

Synchronizes updates to the node to the underlying media, if it exists.

This method will return when the filesystem server has flushed the relevant updates to the underlying media, but does not guarantee the underlying media has persisted the information, nor that any information is committed to hardware. Clients may use Sync to ensure ordering between operations.

This method does not require any rights.

Request

<EMPTY>

Response

UpdateAttributes

Updates information about the node.

• attributes the presence of a table field in attributes indicates the intent to update the corresponding attribute.

This method requires the Rights.UPDATE_ATTRIBUTES right.

Request

Response

Openable

Defined in fuchsia.io/directory.fidl

Open

Opens a new object relative to this directory object.

path may contain multiple segments, separated by "/" characters, and should never be empty; i.e. "" is an invalid path. A trailing slash implies OpenFlags.DIRECTORY. Components must not be empty (i.e. "foo//bar" is invalid). ".." is disallowed anywhere in the path. "." is only allowed if the path is exactly ".", but not otherwise. A leading '/' is allowed (and is treated the same way as if not present, i.e. "/foo/bar' and "foo/bar" are the same).

If an unknown value is sent for flags the connection should be closed.

OpenFlags.RIGHT_* flags provided in flags will restrict access rights on the object channel which will be connected to the opened entity.

Rights are never increased. When you open a nested entity within a directory, you may only request the same rights as what the directory connection already has, or a subset of those. Exceeding those rights causes an access denied error to be transmitted in the OnOpen event if applicable, and the object connection closed.

mode is only used if an object is created and indicates the type of object to be created. An unsupported mode will cause the connection to be closed. The mode type, if set, must always be consistent with the OpenFlags.DIRECTORY and OpenFlags.NOT_DIRECTORY flags, even if an object is not being created. If an object is not being created, mode is otherwise ignored. If an object is being created and the mode type is not set, a directory will be created if OpenFlags.DIRECTORY is set (explicitly or implicitly), or otherwise a server chosen object type.

Request

Readable

Defined in fuchsia.io/file2.fidl

Read

Reads up to 'count' bytes at the seek offset. The seek offset is moved forward by the number of bytes read.

Invariants

• The returned data.length will never be greater than count.
• If data.length is less than count, it means that the seek offset has reached the end of file as part of this operation.
• If data.length is zero while count is not, it means that the seek offset is already at or beyond the end of file, and no data could be read.
• If count is zero, the server should perform all the checks ensuring read access without actually read anything, and return an empty data vector.

This method requires the Rights.READ_BYTES right.

Returns ZX_ERR_OUT_OF_RANGE if count is greater than MAX_TRANSFER_SIZE.

Request

Response

Writable

Defined in fuchsia.io/file2.fidl

Write

Writes data at the seek offset. The seek offset is moved forward by the number of bytes written. If the file is in append mode, the seek offset is first set to the end of the file, followed by the write, in one atomic step.

The file size may grow if the seek offset plus data.length is beyond the current end of file.

• request data the byte buffer to write to the file.

• response actual_count the number of bytes written.

Invariants

• The returned actual_count will never be greater than data.length.
• If the server is unable to write all the data due to e.g. not enough space, actual_count may be less than data.length. If no bytes could be written, an error is returned.
• If data.length is zero, the server should perform all the checks ensuring write access without mutating the file and return a successful write of zero bytes. The seek offset is still updated if in append mode.

This method requires the Rights.WRITE_BYTES right.

Request

Response

STRUCTS

AdvisoryLockRange

Defined in fuchsia.io/locking.fidl

AdvisoryLocking_AdvisoryLock_Response

Defined in fuchsia.io/locking.fidl

<EMPTY>

Directory2_Rename_Response

Defined in fuchsia.io/directory2.fidl

<EMPTY>

Directory2_Unlink_Response

Defined in fuchsia.io/directory2.fidl

<EMPTY>

DirectoryIterator_GetNext_Response

Defined in fuchsia.io/directory2.fidl

DirectoryObject

Defined in fuchsia.io/node.fidl

<EMPTY>

FileObject resource

Defined in fuchsia.io/node.fidl

File_GetBackingMemory_Response resource

Defined in fuchsia.io/file2.fidl

File_ReadAt_Response

Defined in fuchsia.io/file2.fidl

File_Resize_Response

Defined in fuchsia.io/file2.fidl

<EMPTY>

File_Seek_Response

Defined in fuchsia.io/file2.fidl

File_WriteAt_Response

Defined in fuchsia.io/file2.fidl

FilesystemInfo

Defined in fuchsia.io/node.fidl

InotifyEvent

Defined in fuchsia.io/inotify.fidl

Node2_Sync_Response

Defined in fuchsia.io/node2.fidl

<EMPTY>

Node2_UpdateAttributes_Response

Defined in fuchsia.io/node2.fidl

<EMPTY>

NodeAttributes

Defined in fuchsia.io/node.fidl

NodeAttributes defines generic information about a filesystem node.

NodeAttributes2

Defined in fuchsia.io/node2.fidl

Readable_Read_Response

Defined in fuchsia.io/file2.fidl

RightsRequest

Defined in fuchsia.io/rights-request.fidl

Options for requesting rights on the new connection.

Rights Hierarchy

Respecting principles of least privileges, rights in general must meet the following restrictions:

• A connection must have nonzero rights.
• From the perspective of a client, rights must never increase in a derived connection.
• From the perspective of a directory proxy, it must ensure that new connections opened through it cannot have more rights than the connection where the proxy received the Open/Reopen call.

The proper enforcement of the rights hierarchy is a powerful refinement over the existing access control facilities offered by directory sandboxing.

Rights vs Abilities

The rights on a connection limits the set of operations allowed on that connection, but does not guarantee their availability, because the object may not support it.

See Rights and Abilities.

Implementation Notes

When a directory proxy encounters an absent rights field, let r be the rights on the connection where it received this request, the proxy should fill in this field with the following:

RightsRequest {
    at_most: r,
    at_least: 0,
    resolution: RightsResolution.MAXIMIZE,
}

before forwarding the request to the remote party.

Because opening a new connection may involve multiple hops through directory proxies, we require the client to set an upper bound and lower bound on the rights request, and intermediate proxies to refine these bounds.

The rights manipulation should be implemented mechanically without knowledge of any specific rights, and servers should propagate unknown bits members, to gracefully handle future rights extensions.

Implementation Notes

It could be common for a client to request an exact set of rights. We recommend client libraries to define a helper function like follows:

fn Exact(exact_rights: Rights) -> RightsRequest {
    RightsRequest {
        at_most: exact_rights,
        at_least: exact_rights,
        resolution: RightsResolution.MAXIMIZE,
    }
}

at_most ⊋ {}
at_most ⊃ at_least
rights_on_connection_where_open_is_received ⊋ {}
rights_on_connection_where_open_is_received ⊃ at_least

Service

Defined in fuchsia.io/node.fidl

<EMPTY>

Writable_Write_Response

Defined in fuchsia.io/file2.fidl

ENUMS

AdvisoryLockType strict

Type: uint32

Defined in fuchsia.io/locking.fidl

DirentType strict

Type: uint8

Defined in fuchsia.io/directory.fidl

OpenMode strict

Type: uint32

Defined in fuchsia.io/directory2.fidl

RightsResolution strict

Type: uint32

Defined in fuchsia.io/rights-request.fidl

SeekOrigin strict

Type: uint32

Defined in fuchsia.io/file2.fidl

The reference point for updating the seek offset. See File.Seek.

This enum matches the zx_stream_seek_origin_t enum.

WatchEvent strict

Type: uint8

Defined in fuchsia.io/directory.fidl

TABLES

AdvisoryLockRequest

Defined in fuchsia.io/locking.fidl

ConnectionInfo resource

Defined in fuchsia.io/node2.fidl

ConnectorInfo

Defined in fuchsia.io/node2.fidl

DirectoryEntry

Defined in fuchsia.io/directory2.fidl

DirectoryEnumerateOptions

Defined in fuchsia.io/directory2.fidl

DirectoryInfo

Defined in fuchsia.io/node2.fidl

FileInfo resource

Defined in fuchsia.io/file2.fidl

Auxiliary data for the file representation of a node.

ImmutableNodeAttributes

Defined in fuchsia.io/node2.fidl

MutableNodeAttributes

Defined in fuchsia.io/node2.fidl

NodeOptions

Defined in fuchsia.io/directory2.fidl

NodeProtocols

Defined in fuchsia.io/directory2.fidl

UnlinkOptions

Defined in fuchsia.io/directory2.fidl

UNIONS

AdvisoryLocking_AdvisoryLock_Result strict

Defined in fuchsia.io/locking.fidl

ConnectionProtocols flexible

Defined in fuchsia.io/directory2.fidl

Directory2_Rename_Result strict

Defined in fuchsia.io/directory2.fidl

Directory2_Unlink_Result strict

Defined in fuchsia.io/directory2.fidl

DirectoryIterator_GetNext_Result strict

Defined in fuchsia.io/directory2.fidl

File_GetBackingMemory_Result strict resource

Defined in fuchsia.io/file2.fidl

File_ReadAt_Result strict

Defined in fuchsia.io/file2.fidl

File_Resize_Result strict

Defined in fuchsia.io/file2.fidl

File_Seek_Result strict

Defined in fuchsia.io/file2.fidl

File_WriteAt_Result strict

Defined in fuchsia.io/file2.fidl

Node2_GetAttributes_Result strict

Defined in fuchsia.io/node2.fidl

Node2_Sync_Result strict

Defined in fuchsia.io/node2.fidl

Node2_UpdateAttributes_Result strict

Defined in fuchsia.io/node2.fidl

NodeInfoDeprecated strict resource

Defined in fuchsia.io/node.fidl

Readable_Read_Result strict

Defined in fuchsia.io/file2.fidl

Representation flexible resource

Defined in fuchsia.io/node2.fidl

Writable_Write_Result strict

Defined in fuchsia.io/file2.fidl

BITS

ConnectorFlags flexible

Type: uint64

Defined in fuchsia.io/directory2.fidl

DirectoryProtocolFlags flexible

Type: uint64

Defined in fuchsia.io/directory2.fidl

FileProtocolFlags flexible

Type: uint64

Defined in fuchsia.io/directory2.fidl

FileSignal strict

Type: uint32

Defined in fuchsia.io/file2.fidl

InotifyWatchMask strict

Type: uint32

Defined in fuchsia.io/inotify.fidl

Used by InotifyAddWatch to indicate the server the events to be watched on. Also used by Node.Inotify to indicate the types of events that occurred on server side, to be notified to clients. See InotifyEvent.

NodeAttributeFlags strict

Type: uint32

Defined in fuchsia.io/node.fidl

The fields of 'attributes' which are used to update the Node are indicated by the 'flags' argument.

NodeAttributesQuery strict

Type: uint64

Defined in fuchsia.io/node2.fidl

NodeFlags flexible

Type: uint64

Defined in fuchsia.io/directory2.fidl

NodeProtocolKinds flexible

Type: uint64

Defined in fuchsia.io/node-protocols.fidl

A node may have multiple supported representations when opening, even though it may have a fixed underlying identity.

Today, a file is accessed via the File protocol, and sends a Representation.FileInfo when opened with GET_REPRESENTATION. However, in the future we might introduce a more sophisticated FileV2 protocol, or a more efficient SuperFastFile backed by a specialized kernel object. New clients can request the more advanced representations by specifying the corresponding bits in NodeProtocolKinds, whereas existing clients would continue to talk to the node via the old representation.

NodeProtocolKinds enables forward-compatibility through a form of protocol negotiation.

The elements have one-to-one correspondence with the members of Representation.

OpenFlags strict

Type: uint32

Defined in fuchsia.io/directory.fidl

Operations strict

Type: uint64

Defined in fuchsia.io/rights-abilities.fidl

The common members definition behind Rights and Abilities. Note that Directory operations are distinct from File operations, with the exception of some common operations (e.g. GET_ATTRIBUTES) defined on the underlying Node.

UnlinkFlags strict

Type: uint64

Defined in fuchsia.io/directory2.fidl

VmoFlags strict

Type: uint32

Defined in fuchsia.io/file2.fidl

WatchMask strict

Type: uint32

Defined in fuchsia.io/directory.fidl

CONSTANTS

ALIASES