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VOP_GETEXTATTR(9)      FreeBSD Kernel Developer's Manual     VOP_GETEXTATTR(9)

NAME
     VOP_GETEXTATTR -- retrieve	named extended attribute from a	vnode

SYNOPSIS
     #include <sys/param.h>
     #include <sys/vnode.h>
     #include <sys/extattr.h>

     int
     VOP_GETEXTATTR(struct vnode *vp, int attrnamespace, const char *name,
	 struct	uio *uio, size_t *size,	struct ucred *cred,
	 struct	thread *td);

DESCRIPTION
     This vnode	call may be used to retrieve a specific	named extended
     attribute from a file or directory.

     Its arguments are:

     vp		    The	vnode of the file or directory.

     attrnamespace  Integer constant indicating	which extended attribute
		    namespace the attribute name is present in.

     name	    Pointer to a null-terminated character string containing
		    the	attribute name.

     uio	    The	location of the	data to	be read.

     size	    If not NULL, on return it will contain the number of bytes
		    required to	read all of the	attribute data.	 In most cases
		    uio	will be	NULL when size is not, and vice	versa.

     cred	    The	user credentials to use	in authorizing the request.

     td		    The	thread requesting the extended attribute.

     The cred pointer may be NULL to indicate that access control checks are
     not to be performed, if possible.	This cred setting might	be used	to
     allow the kernel to authorize extended attribute retrieval	that the
     active process might not be permitted to do.

     Extended attribute	semantics may vary by file system implementing the
     call.  More information on	extended attributes may	be found in
     extattr(9).

LOCKS
     The vnode will be locked on entry and should remain locked	on return.

RETURN VALUES
     On	success, zero will be returned,	and the	uio structure will be updated
     to	reflect	data read.  Otherwise, an appropriate error code is returned.

ERRORS
     [ENOATTR]		The requested attribute	was not	defined	for this
			vnode.

     [EACCES]		The caller does	not have the appropriate privilege.

     [ENXIO]		The request was	not valid in this file system for the
			specified vnode	and attribute name.

     [ENOMEM]		Sufficient memory is not available to fulfill the
			request.

     [EFAULT]		The uio	structure refers to an invalid userspace
			address.

     [EINVAL]		The name, namespace, or	uio argument is	invalid.

     [EOPNOTSUPP]	The file system	does not support VOP_GETEXTATTR().

SEE ALSO
     extattr(9), vnode(9), VOP_LISTEXTATTR(9), VOP_SETEXTATTR(9)

BUGS
     By	passing	in the empty string as the attribute name, some	file systems
     will return a list	of defined names on the	target vnode for the requested
     namespace.	 This is a bad API, and	will be	replaced by an explicit	VOP.

FreeBSD	10.1		       December	23, 1999		  FreeBSD 10.1

NAME | SYNOPSIS | DESCRIPTION | LOCKS | RETURN VALUES | ERRORS | SEE ALSO | BUGS

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