fuchsia.io

PROTOCOLS

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

Name	Type
`request`	`fuchsia.io2/AdvisoryLockRequest`

Response

Name	Type
`result`	`fuchsia.io2/AdvisoryLocking_AdvisoryLock_Result`

Clone

Create another connection to the same remote object.

flags may be any of:

OPEN_RIGHT_*
OPEN_FLAG_APPEND
OPEN_FLAG_NO_REMOTE
OPEN_FLAG_DESCRIBE
CLONE_FLAG_SAME_RIGHTS

All other flags are ignored.

The OPEN_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 CLONE_FLAG_SAME_RIGHTS to inherit the rights on the source connection. It is invalid to pass any of the OPEN_RIGHT_* flags together with CLONE_FLAG_SAME_RIGHTS.

Request

Name	Type
`flags`	`uint32`
`object`	`request<Node>`

Close

Terminates connection with object.

This method does not require any rights.

Request

Name	Type

Response

Name	Type
`s`	`zx/status`

Describe

Returns extra information about the type of the object. If the Describe operation fails, the connection is closed.

This method does not require any rights.

Request

Name	Type

Response

Name	Type
`info`	`NodeInfo`

GetAttr

Acquires information about the node.

This method does not require any rights.

Request

Name	Type

Response

Name	Type
`s`	`zx/status`
`attributes`	`NodeAttributes`

GetToken

Acquires a token to a Directory which can be used to identify access to it at a later point in time.

This method requires following rights: OPEN_RIGHT_WRITABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

Name	Type

Response

Name	Type
`s`	`zx/status`
`token`	`handle<handle>?`

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: OPEN_RIGHT_WRITABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

Name	Type
`src`	`string[4096]`
`dst_parent_token`	`handle<handle>`
`dst`	`string[4096]`

Response

Name	Type
`s`	`zx/status`

NodeGetFlags

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

This method does not require any rights. This method has the same functionality as GetFlags for File and is meant as an in-progress replacement.

Request

Name	Type

Response

Name	Type
`s`	`zx/status`
`flags`	`uint32`

NodeSetFlags

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

OPEN_FLAG_APPEND

This method does not require any rights. This method has the same functionality as SetFlags for File and is meant as an in-progress replacement.

Request

Name	Type
`flags`	`uint32`

Response

Name	Type
`s`	`zx/status`

OnOpen

An event produced eagerly by a FIDL server if requested by OPEN_FLAG_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

Name	Type
`s`	`zx/status`
`info`	`NodeInfo?`

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 OPEN_FLAG_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).

flags may be any of the OPEN_FLAG_* and OPEN_RIGHT_* values, bitwise ORed together. The OPEN_FLAG_DESCRIBE flag may cause an OnOpen event to be transmitted on the object handle, indicating the type of object opened.

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

OPEN_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.

The caller must specify either one or more of the OPEN_RIGHT_* flags, or the OPEN_FLAG_NODE_REFERENCE flag.

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 OPEN_FLAG_DIRECTORY and OPEN_FLAG_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 OPEN_FLAG_DIRECTORY is set (explicitly or implicitly), or otherwise a server chosen object type.

Request

Name	Type
`flags`	`uint32`
`mode`	`uint32`
`path`	`string[4096]`
`object`	`request<Node>`

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.

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 `DIRENT_TYPE_*` 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

Name	Type
`max_bytes`	`uint64`

Response

Name	Type
`s`	`zx/status`
`dirents`	`vector<uint8>[8192]`

Rename

Renames an object named src to the name dst, in a directory represented by token.

src/dst must be resolved object names. Including "/" in any position other than the end of the string will return ZX_ERR_INVALID_ARGS. Returning "/" at the end of either string implies that it must be a directory, or else ZX_ERR_NOT_DIR should be returned.

This method requires following rights: OPEN_RIGHT_WRITABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

Name	Type
`src`	`string[4096]`
`dst_parent_token`	`handle<handle>`
`dst`	`string[4096]`

Response

Name	Type
`s`	`zx/status`

Rename2

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 fuchsia.io2/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

Name	Type
`src`	`fuchsia.io2/Name`
`dst_parent_token`	`fuchsia.io2/Token`
`dst`	`fuchsia.io2/Name`

Response

Name	Type
`result`	`Directory_Rename2_Result`

Rewind

Resets the directory seek offset.

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

Request

Name	Type

Response

Name	Type
`s`	`zx/status`

SetAttr

Updates information about the node. flags may be any of NODE_ATTRIBUTE_FLAG_*.

This method requires following rights: OPEN_RIGHT_WRITABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

Name	Type
`flags`	`uint32`
`attributes`	`NodeAttributes`

Response

Name	Type
`s`	`zx/status`

Sync

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

This method does not require any rights.

Request

Name	Type

Response

Name	Type
`s`	`zx/status`

Unlink

Detaches an object from this directory object.

The underlying object may or may not be deleted after this method completes: 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 removed.

If a directory is unlinked while it still has an open reference, it must become read-only, preventing new entries from being created until all references close and the directory is destroyed.

path identifies the file which should be detached. If path contains multiple segments, separated by "/" characters, then the directory is traversed, one segment at a time, relative to the originally accessed Directory.

Returns: ZX_ERR_ACCESS_DENIED if the connection (or the underlying filesystem) does not allow writable access. ZX_ERR_INVALID_ARGS if path contains ".." segments. ZX_ERR_NOT_EMPTY if path refers to a non-empty directory. ZX_ERR_UNAVAILABLE if path refers to a mount point, containing a remote channel. ZX_ERR_UNAVAILABLE if path is ".".

Other errors may be returned for filesystem-specific reasons.

This method requires following rights: OPEN_RIGHT_WRITABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

Name	Type
`path`	`string[4096]`

Response

Name	Type
`s`	`zx/status`

Unlink2

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

Name	Type
`name`	`fuchsia.io2/Name`
`options`	`fuchsia.io2/UnlinkOptions`

Response

Name	Type
`result`	`Directory_Unlink2_Result`

Watch

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

The watcher handle will send messages of the form:

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

Where names are NOT null-terminated.

This API is unstable; in the future, watcher will be a DirectoryWatcher client.

Mask specifies a bitmask of events to observe. Options must be zero; it is reserved.

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

Request

Name	Type
`mask`	`uint32`
`options`	`uint32`
`watcher`	`handle<channel>`

Response

Name	Type
`s`	`zx/status`

DirectoryAdmin

Defined in fuchsia.io/io.fidl

DirectoryAdmin defines a directory which is capable of handling administrator tasks within the filesystem.

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 "/".

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

Name	Type
`path`	`fuchsia.io2/Path`
`filter`	`fuchsia.io2/InotifyWatchMask`
`watch_descriptor`	`uint32`
`socket`	`handle<socket>`

Response

Name	Type

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

Name	Type
`request`	`fuchsia.io2/AdvisoryLockRequest`

Response

Name	Type
`result`	`fuchsia.io2/AdvisoryLocking_AdvisoryLock_Result`

Clone

Create another connection to the same remote object.

flags may be any of:

OPEN_RIGHT_*
OPEN_FLAG_APPEND
OPEN_FLAG_NO_REMOTE
OPEN_FLAG_DESCRIBE
CLONE_FLAG_SAME_RIGHTS

All other flags are ignored.

Request

Name	Type
`flags`	`uint32`
`object`	`request<Node>`

Close

Terminates connection with object.

This method does not require any rights.

Request

Name	Type

Response

Name	Type
`s`	`zx/status`

Describe

Returns extra information about the type of the object. If the Describe operation fails, the connection is closed.

This method does not require any rights.

Request

Name	Type

Response

Name	Type
`info`	`NodeInfo`

GetAttr

Acquires information about the node.

This method does not require any rights.

Request

Name	Type

Response

Name	Type
`s`	`zx/status`
`attributes`	`NodeAttributes`

GetDevicePath

Acquire the path to the device backing this filesystem, if there is one.

Request

Name	Type

Response

Name	Type
`s`	`zx/status`
`path`	`string[4096]?`

GetToken

Acquires a token to a Directory which can be used to identify access to it at a later point in time.

This method requires following rights: OPEN_RIGHT_WRITABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

Name	Type

Response

Name	Type
`s`	`zx/status`
`token`	`handle<handle>?`

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: OPEN_RIGHT_WRITABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

Name	Type
`src`	`string[4096]`
`dst_parent_token`	`handle<handle>`
`dst`	`string[4096]`

Response

Name	Type
`s`	`zx/status`

Mount

Mount a channel representing a remote filesystem onto this directory. All future requests to this node will be forwarded to the remote filesystem. To re-open a node without forwarding to the remote target, the node should be opened with OPEN_FLAG_NO_REMOTE.

Request

Name	Type
`remote`	`Directory`

Response

Name	Type
`s`	`zx/status`

MountAndCreate

Atomically create a directory with a provided path, and mount the remote handle to the newly created directory.

Request

Name	Type
`remote`	`Directory`
`name`	`string[255]`
`flags`	`uint32`

Response

Name	Type
`s`	`zx/status`

NodeGetFlags

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

This method does not require any rights. This method has the same functionality as GetFlags for File and is meant as an in-progress replacement.

Request

Name	Type

Response

Name	Type
`s`	`zx/status`
`flags`	`uint32`

NodeSetFlags

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

OPEN_FLAG_APPEND

This method does not require any rights. This method has the same functionality as SetFlags for File and is meant as an in-progress replacement.

Request

Name	Type
`flags`	`uint32`

Response

Name	Type
`s`	`zx/status`

OnOpen

An event produced eagerly by a FIDL server if requested by OPEN_FLAG_DESCRIBE.

Response

Name	Type
`s`	`zx/status`
`info`	`NodeInfo?`

Open

Opens a new object relative to this directory object.

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

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

The caller must specify either one or more of the OPEN_RIGHT_* flags, or the OPEN_FLAG_NODE_REFERENCE flag.

Request

Name	Type
`flags`	`uint32`
`mode`	`uint32`
`path`	`string[4096]`
`object`	`request<Node>`

QueryFilesystem

Query the filesystem for filesystem-specific information.

Request

Name	Type

Response

Name	Type
`s`	`zx/status`
`info`	`FilesystemInfo?`

ReadDirents

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 `DIRENT_TYPE_*` 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

Name	Type
`max_bytes`	`uint64`

Response

Name	Type
`s`	`zx/status`
`dirents`	`vector<uint8>[8192]`

Rename

Renames an object named src to the name dst, in a directory represented by token.

This method requires following rights: OPEN_RIGHT_WRITABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

Name	Type
`src`	`string[4096]`
`dst_parent_token`	`handle<handle>`
`dst`	`string[4096]`

Response

Name	Type
`s`	`zx/status`

Rename2

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 fuchsia.io2/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

Name	Type
`src`	`fuchsia.io2/Name`
`dst_parent_token`	`fuchsia.io2/Token`
`dst`	`fuchsia.io2/Name`

Response

Name	Type
`result`	`Directory_Rename2_Result`

Rewind

Resets the directory seek offset.

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

Request

Name	Type

Response

Name	Type
`s`	`zx/status`

SetAttr

Updates information about the node. flags may be any of NODE_ATTRIBUTE_FLAG_*.

This method requires following rights: OPEN_RIGHT_WRITABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

Name	Type
`flags`	`uint32`
`attributes`	`NodeAttributes`

Response

Name	Type
`s`	`zx/status`

Sync

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

This method does not require any rights.

Request

Name	Type

Response

Name	Type
`s`	`zx/status`

Unlink

Detaches an object from this directory object.

If a directory is unlinked while it still has an open reference, it must become read-only, preventing new entries from being created until all references close and the directory is destroyed.

Other errors may be returned for filesystem-specific reasons.

This method requires following rights: OPEN_RIGHT_WRITABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

Name	Type
`path`	`string[4096]`

Response

Name	Type
`s`	`zx/status`

Unlink2

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

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

Name	Type
`name`	`fuchsia.io2/Name`
`options`	`fuchsia.io2/UnlinkOptions`

Response

Name	Type
`result`	`Directory_Unlink2_Result`

Unmount

Unmount this filesystem. After this function returns successfully, all connections to the filesystem will be terminated.

Request

Name	Type

Response

Name	Type
`s`	`zx/status`

UnmountNode

Detach a node which was previously attached to this directory with Mount.

Request

Name	Type

Response

Name	Type
`s`	`zx/status`
`remote`	`Directory?`

Watch

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

The watcher handle will send messages of the form:

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

Where names are NOT null-terminated.

This API is unstable; in the future, watcher will be a DirectoryWatcher client.

Mask specifies a bitmask of events to observe. Options must be zero; it is reserved.

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

Request

Name	Type
`mask`	`uint32`
`options`	`uint32`
`watcher`	`handle<channel>`

Response

Name	Type
`s`	`zx/status`

DirectoryWatcher

Defined in fuchsia.io/io.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.

OnEvent

Request

Name	Type
`events`	`vector<uint8>[8192]`

File

Defined in fuchsia.io/io.fidl

File defines the interface of a node which contains a flat layout of data.

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

Name	Type
`request`	`fuchsia.io2/AdvisoryLockRequest`

Response

Name	Type
`result`	`fuchsia.io2/AdvisoryLocking_AdvisoryLock_Result`

Clone

Create another connection to the same remote object.

flags may be any of:

OPEN_RIGHT_*
OPEN_FLAG_APPEND
OPEN_FLAG_NO_REMOTE
OPEN_FLAG_DESCRIBE
CLONE_FLAG_SAME_RIGHTS

All other flags are ignored.

Request

Name	Type
`flags`	`uint32`
`object`	`request<Node>`

Close

Terminates connection with object.

This method does not require any rights.

Request

Name	Type

Response

Name	Type
`s`	`zx/status`

Describe

Returns extra information about the type of the object. If the Describe operation fails, the connection is closed.

This method does not require any rights.

Request

Name	Type

Response

Name	Type
`info`	`NodeInfo`

GetAttr

Acquires information about the node.

This method does not require any rights.

Request

Name	Type

Response

Name	Type
`s`	`zx/status`
`attributes`	`NodeAttributes`

GetBuffer

Acquires a buffer representing this file, if there is one, with the requested access rights.

flags may be any of VMO_FLAG_*.

This method requires following rights:

OPEN_RIGHT_WRITABLE if flags includes VMO_FLAG_WRITE.
OPEN_RIGHT_READABLE if flags includes VMO_FLAG_READ or VMO_FLAG_EXEC.

Request

Name	Type
`flags`	`uint32`

Response

Name	Type
`s`	`zx/status`
`buffer`	`fuchsia.mem/Buffer?`

GetFlags

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

This method does not require any rights.

Request

Name	Type

Response

Name	Type
`s`	`zx/status`
`flags`	`uint32`

NodeGetFlags

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

This method does not require any rights. This method has the same functionality as GetFlags for File and is meant as an in-progress replacement.

Request

Name	Type

Response

Name	Type
`s`	`zx/status`
`flags`	`uint32`

NodeSetFlags

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

OPEN_FLAG_APPEND

This method does not require any rights. This method has the same functionality as SetFlags for File and is meant as an in-progress replacement.

Request

Name	Type
`flags`	`uint32`

Response

Name	Type
`s`	`zx/status`

OnOpen

An event produced eagerly by a FIDL server if requested by OPEN_FLAG_DESCRIBE.

Response

Name	Type
`s`	`zx/status`
`info`	`NodeInfo?`

Read

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

This method requires following rights: OPEN_RIGHT_READABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

Name	Type
`count`	`uint64`

Response

Name	Type
`s`	`zx/status`
`data`	`vector<uint8>[8192]`

ReadAt

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

This method requires following rights: OPEN_RIGHT_READABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

Name	Type
`count`	`uint64`
`offset`	`uint64`

Response

Name	Type
`s`	`zx/status`
`data`	`vector<uint8>[8192]`

Seek

Moves the offset at which the next invocation of Read() or Write() will occur.

This method does not require any rights.

Request

Name	Type
`offset`	`int64`
`start`	`SeekOrigin`

Response

Name	Type
`s`	`zx/status`
`offset`	`uint64`

SetAttr

Updates information about the node. flags may be any of NODE_ATTRIBUTE_FLAG_*.

This method requires following rights: OPEN_RIGHT_WRITABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

Name	Type
`flags`	`uint32`
`attributes`	`NodeAttributes`

Response

Name	Type
`s`	`zx/status`

SetFlags

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

OPEN_FLAG_APPEND

This method does not require any rights.

Request

Name	Type
`flags`	`uint32`

Response

Name	Type
`s`	`zx/status`

Sync

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

This method does not require any rights.

Request

Name	Type

Response

Name	Type
`s`	`zx/status`

Truncate

Shrinks the file size to 'length' bytes.

This method requires following rights: OPEN_RIGHT_WRITABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

Name	Type
`length`	`uint64`

Response

Name	Type
`s`	`zx/status`

Write

Writes data at the seek offset. The seek offset is moved forward by the number of bytes written.

This method requires following rights: OPEN_RIGHT_WRITABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

Name	Type
`data`	`vector<uint8>[8192]`

Response

Name	Type
`s`	`zx/status`
`actual`	`uint64`

WriteAt

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

This method requires following rights: OPEN_RIGHT_WRITABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

Name	Type
`data`	`vector<uint8>[8192]`
`offset`	`uint64`

Response

Name	Type
`s`	`zx/status`
`actual`	`uint64`

Node

Defined in fuchsia.io/io.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:

OPEN_RIGHT_*
OPEN_FLAG_APPEND
OPEN_FLAG_NO_REMOTE
OPEN_FLAG_DESCRIBE
CLONE_FLAG_SAME_RIGHTS

All other flags are ignored.

Request

Name	Type
`flags`	`uint32`
`object`	`request<Node>`

Close

Terminates connection with object.

This method does not require any rights.

Request

Name	Type

Response

Name	Type
`s`	`zx/status`

Describe

Returns extra information about the type of the object. If the Describe operation fails, the connection is closed.

This method does not require any rights.

Request

Name	Type

Response

Name	Type
`info`	`NodeInfo`

GetAttr

Acquires information about the node.

This method does not require any rights.

Request

Name	Type

Response

Name	Type
`s`	`zx/status`
`attributes`	`NodeAttributes`

NodeGetFlags

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

This method does not require any rights. This method has the same functionality as GetFlags for File and is meant as an in-progress replacement.

Request

Name	Type

Response

Name	Type
`s`	`zx/status`
`flags`	`uint32`

NodeSetFlags

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

OPEN_FLAG_APPEND

This method does not require any rights. This method has the same functionality as SetFlags for File and is meant as an in-progress replacement.

Request

Name	Type
`flags`	`uint32`

Response

Name	Type
`s`	`zx/status`

OnOpen

An event produced eagerly by a FIDL server if requested by OPEN_FLAG_DESCRIBE.

Response

Name	Type
`s`	`zx/status`
`info`	`NodeInfo?`

SetAttr

Updates information about the node. flags may be any of NODE_ATTRIBUTE_FLAG_*.

This method requires following rights: OPEN_RIGHT_WRITABLE, otherwise returns ZX_ERR_BAD_HANDLE.

Request

Name	Type
`flags`	`uint32`
`attributes`	`NodeAttributes`

Response

Name	Type
`s`	`zx/status`

Sync

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

This method does not require any rights.

Request

Name	Type

Response

Name	Type
`s`	`zx/status`

STRUCTS

DatagramSocket resource

Defined in fuchsia.io/io.fidl

A NodeInfo variant.

Name	Type	Description	Default
`event`	`handle<eventpair>`	See fuchsia.posix.socket.DatagramSocket for details.	No default

Device resource

Defined in fuchsia.io/io.fidl

A NodeInfo variant.

Name Type Description Default

event

handle<eventpair>?

An optional event which transmits information about a device's state.

The "DEVICE_SIGNAL_" values may be observed on this event.

No default

DirectoryObject

Defined in fuchsia.io/io.fidl

A NodeInfo variant.

Name	Type	Description	Default

Directory_Rename2_Response

Defined in fuchsia.io/io.fidl

Name	Type	Description	Default

Directory_Unlink2_Response

Defined in fuchsia.io/io.fidl

Name	Type	Description	Default

FileObject resource

Defined in fuchsia.io/io.fidl

A NodeInfo variant.

Name Type Description Default

event

handle<event>?

An optional event which transmits information about an object's readability or writability. This event relays information about the underlying object, not the capability granted to client: this event may be signalled "readable" on a connection that does not have the capability to read.

The "FILE_SIGNAL_" values may be observed on this event.

No default

stream

handle<stream>?

A placeholder for future stream support.

Currently, servers are required not to send a handle in this field.

No default

FilesystemInfo

Defined in fuchsia.io/io.fidl

Name	Type	Description	Default
`total_bytes`	`uint64`	The number of data bytes which may be stored in a filesystem.	No default
`used_bytes`	`uint64`	The number of data bytes which are in use by the filesystem.	No default
`total_nodes`	`uint64`	The number of nodes which may be stored in the filesystem.	No default
`used_nodes`	`uint64`	The number of nodes used by the filesystem.	No default
`free_shared_pool_bytes`	`uint64`	The amount of space which may be allocated from the underlying volume manager. If unsupported, this will be zero.	No default
`fs_id`	`uint64`	A unique identifier for this filesystem instance. Will not be preserved across reboots.	No default
`block_size`	`uint32`	The size of a single filesystem block.	No default
`max_filename_size`	`uint32`	The maximum length of a filesystem name.	No default
`fs_type`	`uint32`	A unique identifier for the type of the underlying filesystem.	No default
`padding`	`uint32`		No default
`name`	`int8[32]`		No default

NodeAttributes

Defined in fuchsia.io/io.fidl

NodeAttributes defines generic information about a filesystem node.

Name	Type	Description	Default
`mode`	`uint32`	Protection bits and node type information describe in 'mode'.	No default
`id`	`uint64`	A filesystem-unique ID.	No default
`content_size`	`uint64`	Node size, in bytes.	No default
`storage_size`	`uint64`	Space needed to store node (possibly larger than size), in bytes.	No default
`link_count`	`uint64`	Hard link count.	No default
`creation_time`	`uint64`	Time of creation (may be updated manually after creation) in ns since Unix epoch, UTC.	No default
`modification_time`	`uint64`	Time of last modification in ns since Unix epoch, UTC.	No default

Pipe resource

Defined in fuchsia.io/io.fidl

A NodeInfo variant.

Name	Type	Description	Default
`socket`	`handle<socket>`		No default

Service

Defined in fuchsia.io/io.fidl

A NodeInfo variant.

Name	Type	Description	Default

StreamSocket resource

Defined in fuchsia.io/io.fidl

A NodeInfo variant.

Name	Type	Description	Default
`socket`	`handle<socket>`		No default

Tty resource

Defined in fuchsia.io/io.fidl

A NodeInfo variant.

Name	Type	Description	Default
`event`	`handle<eventpair>?`		No default

Vmofile resource

Defined in fuchsia.io/io.fidl

A NodeInfo variant.

Name	Type	Description	Default
`vmo`	`handle<vmo>`	The VMO which backs this file.	No default
`offset`	`uint64`	The index into `vmo` which represents the first byte of the file.	No default
`length`	`uint64`	The number of bytes, starting at `offset`, which may be used to represent this file.	No default

WatchedEvent

Defined in fuchsia.io/io.fidl

WatchedEvent describes events returned from a DirectoryWatcher.

Name	Type	Default
`event`	`uint8`	No default
`len`	`uint8`	No default
`name`	`vector<uint8>[255]`	No default

ENUMS

SeekOrigin strict

Type: uint32

Defined in fuchsia.io/io.fidl

Update the Seek offset.

Name	Value	Description
`START`	`0`	Seek from the start of the file.
`CURRENT`	`1`	Seek from the current position in the file.
`END`	`2`	Seek from the end of the file.

UNIONS

Directory_Rename2_Result strict

Defined in fuchsia.io/io.fidl

Name	Type	Description
`response`	`Directory_Rename2_Response`
`err`	`zx/status`

Directory_Unlink2_Result strict

Defined in fuchsia.io/io.fidl

Name	Type	Description
`response`	`Directory_Unlink2_Response`
`err`	`zx/status`

NodeInfo strict resource

Defined in fuchsia.io/io.fidl

Connection information.

Refer to Node.Describe and Node.OnOpen for usage.

Name	Type	Description
`service`	`Service`	No protocol information was supplied by the connection.
`file`	`FileObject`	The connection composes File.
`directory`	`DirectoryObject`	The connection composes Directory.
`pipe`	`Pipe`
`vmofile`	`Vmofile`	The connection composes File. Its implementation is backed by a VMO.
`device`	`Device`
`tty`	`Tty`

`datagram_socket`	`DatagramSocket`	The connection composes fuchsia.posix.socket/DatagramSocket.
`stream_socket`	`StreamSocket`	The connection composes fuchsia.posix.socket/StreamSocket.

CONSTANTS

Name	Value	Type	Description
CLONE_FLAG_SAME_RIGHTS	`67108864`	`uint32`	When used during clone, the new connection inherits the rights on the source connection, regardless if it is a file or directory. Otherwise, clone attempts to use the requested rights. It is invalid to pass any of the `OPEN_RIGHT_*` flags together with `CLONE_FLAG_SAME_RIGHTS`.
DEVICE_SIGNAL_ERROR	`134217728`	`uint32`	Indicates the device has encountered an error state.
DEVICE_SIGNAL_HANGUP	`268435456`	`uint32`	Indicates the device has hung up on the current connection.
DEVICE_SIGNAL_OOB	`33554432`	`uint32`	Indicates an out-of-band state transition has occurred.
DEVICE_SIGNAL_READABLE	`16777216`	`uint32`	Indicates the device is ready for reading.
DEVICE_SIGNAL_WRITABLE	`67108864`	`uint32`	Indicates the device is ready for writing.
DIRENT_TYPE_BLOCK_DEVICE	`6`	`uint8`	A dirent representing a block device object.
DIRENT_TYPE_DIRECTORY	`4`	`uint8`	A dirent representing a directory object.
DIRENT_TYPE_FILE	`8`	`uint8`	A dirent representing a file object.
DIRENT_TYPE_SERVICE	`16`	`uint8`	A dirent representing a service object.
DIRENT_TYPE_SOCKET	`12`	`uint8`	A dirent representing a socket object.
DIRENT_TYPE_UNKNOWN	`0`	`uint8`	A dirent with an unknown type.
FILE_SIGNAL_READABLE	`16777216`	`uint32`	Indicates the file is ready for reading.
FILE_SIGNAL_WRITABLE	`33554432`	`uint32`	Indicates the file is ready for writing.
INO_UNKNOWN	`18446744073709551615`	`uint64`	Nodes which do not have ino values should return this value from Readdir and GetAttr.
MAX_BUF	`8192`	`uint64`	The maximal buffer size which can be transmitted for buffered operations. This capacity is currently set somewhat arbitrarily.
MAX_FILENAME	`255`	`uint64`	The maximum length, in bytes, of a single filesystem component.
MAX_FS_NAME_BUFFER	`32`	`uint64`
MAX_PATH	`4096`	`uint64`	The maximum length, in bytes, of a filesystem string.
MODE_PROTECTION_MASK	`4095`	`uint32`	Bits reserved for posix protections. Native fuchsia filesystems are not required to set bits contained within `MODE_PROTECTION_MASK`, but filesystems that wish to do so may refer to sys/stat.h for their definitions.
MODE_TYPE_BLOCK_DEVICE	`24576`	`uint32`
MODE_TYPE_DIRECTORY	`16384`	`uint32`
MODE_TYPE_FILE	`32768`	`uint32`
MODE_TYPE_MASK	`1044480`	`uint32`	Bits indicating node type. The canonical mechanism to check for a node type is to take 'mode', bitwise AND it with the `MODE_TYPE_MASK`, and check exact equality against a mode type.
MODE_TYPE_SERVICE	`65536`	`uint32`
MODE_TYPE_SOCKET	`49152`	`uint32`
MOUNT_CREATE_FLAG_REPLACE	`1`	`uint32`
NODE_ATTRIBUTE_FLAG_CREATION_TIME	`1`	`uint32`	The fields of 'attributes' which are used to update the Node are indicated by the 'flags' argument.
NODE_ATTRIBUTE_FLAG_MODIFICATION_TIME	`2`	`uint32`
OPEN_FLAGS_ALLOWED_WITH_NODE_REFERENCE	`46661632`	`uint32`	Binary OR of `OPEN_FLAG_DIRECTORY`, OPEN_FLAG_NOT_DIRECTORY, OPEN_FLAG_DESCRIBE, and `OPEN_FLAG_NODE_REFERENCE`. Flags used when opening a node reference must fall within this mask.
OPEN_FLAG_APPEND	`1048576`	`uint32`	Seek to the end of the object before all writes.
OPEN_FLAG_CREATE	`65536`	`uint32`	Create the object if it doesn't exist.
OPEN_FLAG_CREATE_IF_ABSENT	`131072`	`uint32`	(with Create) Fail if the object already exists.
OPEN_FLAG_DESCRIBE	`8388608`	`uint32`	Requests that an "OnOpen" event is sent to the interface request. The event will contain a non-null NodeInfo if the open/clone is successful.
OPEN_FLAG_DIRECTORY	`524288`	`uint32`	Assert that the object to be opened is a directory. Return an error if the target object is not a directory.
OPEN_FLAG_NODE_REFERENCE	`4194304`	`uint32`	Open a reference to the object, not the object itself. It is ONLY valid to pass the following flags together with `OPEN_FLAG_NODE_REFERENCE`: `OPEN_FLAG_DIRECTORY` `OPEN_FLAG_NOT_DIRECTORY` `OPEN_FLAG_DESCRIBE` otherwise an error is returned. If an object is opened or cloned using this method, the resulting connection does not carry any permission flags. The resulting node allows a limited set of operations: `GetAttr`, `Clone`, `Close`, `Describe`, and, if the node is a file, these extra operations: `GetFlags`, `SetFlags`.
OPEN_FLAG_NOT_DIRECTORY	`33554432`	`uint32`	Assert that the object to be opened is not a directory. Return an error if the target object is a directory.
OPEN_FLAG_NO_REMOTE	`2097152`	`uint32`	If the object is a mount point, open the local directory.
OPEN_FLAG_POSIX	`16777216`	`uint32`	Specify this flag to request POSIX-compatibility with respect to execute and write permissions. This flag implies OPEN_FLAG_POSIX_WRITABLE and OPEN_FLAG_POSIX_EXECUTABLE. Use of this flag is being deprecated, and should be replaced with a combination of OPEN_FLAG_POSIX_WRITABLE and/or OPEN_FLAG_POSIX_EXECUTABLE.
OPEN_FLAG_POSIX_EXECUTABLE	`268435456`	`uint32`	Specify this flag to request POSIX-compatibility with respect to execute permission handling. Currently, it affects permission handling specifically during Open: If the target path is a directory, the rights on the new connection expand to include `OPEN_RIGHT_EXECUTABLE` if and only if the current connection and all intermediate mount points are executable. Otherwise, this flag is ignored. It is an access denied error to request more rights than those on the current connection, or any intermediate mount points. If this flag is omitted, opening always uses the requested rights, failing the operation with access denied error if requested rights exceeds the rights attached to the current connection. If the requesting connection is read-only and the requested rights are read-only, the flag may be ignored by the server, and is not forwarded downstream. This is an implementation detail, necessary to enforce hierarchical permissions across mount points, and should have no effect on the expected behavior for clients.
OPEN_FLAG_POSIX_WRITABLE	`134217728`	`uint32`	Specify this flag to request POSIX-compatibility with respect to write permission handling. Currently, it affects permission handling specifically during Open: If the target path is a directory, the rights on the new connection expand to include `OPEN_RIGHT_WRITABLE` if and only if the current connection and all intermediate mount points are writable. Otherwise, this flag is ignored. It is an access denied error to request more rights than those on the current connection, or any intermediate mount points. If this flag is omitted, opening always uses the requested rights, failing the operation with access denied error if requested rights exceeds the rights attached to the current connection. If the requesting connection is read-only and the requested rights are read-only, the flag may be ignored by the server, and is not forwarded downstream. This is an implementation detail, necessary to enforce hierarchical permissions across mount points, and should have no effect on the expected behavior for clients.
OPEN_FLAG_TRUNCATE	`262144`	`uint32`	Truncate the object before usage.
OPEN_RIGHT_ADMIN	`4`	`uint32`	Connection can mount/umount filesystem.
OPEN_RIGHT_EXECUTABLE	`8`	`uint32`	Connection can map target object executable.
OPEN_RIGHT_READABLE	`1`	`uint32`	Can read from target object.
OPEN_RIGHT_WRITABLE	`2`	`uint32`	Can write to target object.
VMO_FLAG_EXACT	`131072`	`uint32`	Require an exact (non-cloned) handle to the underlying VMO. The request should fail if a handle to the exact VMO is not returned. May not be supplied with `VMO_FLAG_PRIVATE`.
VMO_FLAG_EXEC	`4`	`uint32`	Requests that the VMO be executable.
VMO_FLAG_PRIVATE	`65536`	`uint32`	Require a copy-on-write clone of the underlying VMO. The request should fail if the VMO is not cloned. May not be supplied with fuchsia_io_`VMO_FLAG_EXACT`.
VMO_FLAG_READ	`1`	`uint32`	Requests that the VMO be readable.
VMO_FLAG_WRITE	`2`	`uint32`	Requests that the VMO be writable.
WATCH_EVENT_ADDED	`1`	`uint8`	Indicates a node has been created (either new or moved) into a directory.
WATCH_EVENT_DELETED	`0`	`uint8`	Indicates the directory being watched has been deleted.
WATCH_EVENT_EXISTING	`3`	`uint8`	Identifies a node already existed in the directory when watching started.
WATCH_EVENT_IDLE	`4`	`uint8`	Identifies that no more `WATCH_EVENT_EXISTING` events will be sent.
WATCH_EVENT_REMOVED	`2`	`uint8`	Identifies a node has been removed (either deleted or moved) from the directory.
WATCH_MASK_ADDED	`2`	`uint32`	Used by `Directory.Watch`. Requests transmission of `WATCH_EVENT_ADDED`.
WATCH_MASK_ALL	`31`	`uint32`	Used by `Directory.Watch`. Requests transmission of all watcher events.
WATCH_MASK_DELETED	`1`	`uint32`	Used by `Directory.Watch`. Requests transmission of `WATCH_EVENT_DELETED`.
WATCH_MASK_EXISTING	`8`	`uint32`	Used by `Directory.Watch`. Requests transmission of `WATCH_EVENT_EXISTING`.
WATCH_MASK_IDLE	`16`	`uint32`	Used by `Directory.Watch`. Requests transmission of `WATCH_EVENT_IDLE`.
WATCH_MASK_REMOVED	`4`	`uint32`	Used by `Directory.Watch`. Requests transmission of `WATCH_EVENT_REMOVED`.