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VACCESS_ACL_POSIX1E(9)	 BSD Kernel Developer's	Manual	VACCESS_ACL_POSIX1E(9)

NAME
     vaccess_acl_posix1e -- generate a POSIX.1e	ACL access control decision
     using vnode parameters

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

     int
     vaccess_acl_posix1e(enum vtype type, uid_t	file_uid, gid_t	file_gid,
	 struct	acl *acl, accmode_t accmode, struct ucred *cred,
	 int *privused);

DESCRIPTION
     This call implements the logic for	the UNIX discretionary file security
     model with	POSIX.1e ACL extensions.  It accepts the vnodes	type type,
     owning UID	file_uid, owning GID file_gid, access ACL for the file acl,
     desired access mode accmode, requesting credential	cred, and an optional
     call-by-reference int pointer returning whether or	not privilege was re-
     quired for	successful evaluation of the call; the privused	pointer	may be
     set to NULL by the	caller in order	not to be informed of privilege	infor-
     mation, or	it may point to	an integer that	will be	set to 1 if privilege
     is	used, and 0 otherwise.

     This call is intended to support implementations of VOP_ACCESS(9),	which
     will use their own	access methods to retrieve the vnode properties, and
     then invoke vaccess_acl_posix1e() in order	to perform the actual check.
     Implementations of	VOP_ACCESS(9) may choose to implement additional secu-
     rity mechanisms whose results will	be composed with the return value.

     The algorithm used	by vaccess_acl_posix1e() is based on the POSIX.1e ACL
     evaluation	algorithm.  The	algorithm selects a matching entry from	the
     access ACL, which may then	be composed with an available ACL mask entry,
     providing UNIX security compatibility.

     Once appropriate protections are selected for the current credential, the
     requested access mode, in combination with	the vnode type,	will be	com-
     pared with	the discretionary rights available for the credential.	If the
     rights granted by discretionary protections are insufficient, then	super-
     user privilege, if	available for the credential, will also	be considered.

RETURN VALUES
     vaccess_acl_posix1e() will	return 0 on success, or	a non-zero error value
     on	failure.

ERRORS
     [EACCES]		Permission denied.  An attempt was made	to access a
			file in	a way forbidden	by its file access permis-
			sions.

     [EPERM]		Operation not permitted.  An attempt was made to per-
			form an	operation limited to processes with appropri-
			ate privileges or to the owner of a file or other re-
			source.

SEE ALSO
     vaccess(9), vnode(9), VOP_ACCESS(9)

AUTHORS
     This manual page and the current implementation of	vaccess_acl_posix1e()
     were written by Robert Watson.

BUGS
     This manual page should include a full description	of the POSIX.1e	ACL
     evaluation	algorithm, or cross reference another page that	does.

BSD				August 22, 2001				   BSD

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

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