attr_set, attr_setf - set the value of a user attribute of
a filesystem object
C SYNOPSIS
#include <attr/attributes.h>
int attr_set (const char *path, const char *attrname,
const char *attrvalue, const int valuelength,
int flags);
int attr_setf (int fd, const char *attrname,
const char *attrvalue, const int valuelength,
int flags);
DESCRIPTION
The attr_set and attr_setf functions provide a way to cre
ate attributes and set/change their values.
Path points to a path name for a filesystem object, and fd
refers to the file descriptor associated with a file. If
the attribute attrname does not exist, an attribute with
the given name and value will be created and associated
with that indicated filesystem object. If an attribute
with that name already exists on that filesystem object,
the existing value is replaced with the new value given in
this call. The new attribute value is copied from the
attrvalue buffer for a total of valuelength bytes. The
flags argument can contain the following symbols bitwise
OR´ed together:
ATTR_ROOT
Look for attrname in the root address space, not in
the user address space. (limited to use by super-
user only)
ATTR_DONTFOLLOW
Do not follow symbolic links when resolving a path
on an attr_set function call. The default is to
follow symbolic links.
ATTR_CREATE
Return an error (EEXIST) if an attribute of the
given name already exists on the indicated filesys
tem object, otherwise create an attribute with the
given name and value. This flag is used to imple
ment a pure create operation, without this flag
attr_set will create the attribute if it does not
already exist. An error (EINVAL) will be returned
if both ATTR_CREATE and ATTR_REPLACE are set in the
same call.
ATTR_REPLACE
Return an error (ENOATTR) if an attribute of the
filesystem object, otherwise replace the existing
attribute´s value with the given value. This flag
is used to implement a pure replacement operation,
without this flag attr_set will create the
attribute if it does not already exist. An error
(EINVAL) will be returned if both ATTR_CREATE and
ATTR_REPLACE are set in the same call.
attr_set will fail if one or more of the following are
true:
[ENOATTR] The attribute name given is not associ
ated with the indicated filesystem object
and the ATTR_REPLACE flag bit was set.
[E2BIG] The value of the given attribute is too
large, it exceeds the maximum allowable
size of an attribute value.
[EEXIST] The attribute name given is already asso
ciated with the indicated filesystem
object and the ATTR_CREATE flag bit was
set.
[ENOENT] The named file does not exist.
[EPERM] The effective user ID does not match the
owner of the file and the effective user
ID is not super-user.
[ENOTDIR] A component of the path prefix is not a
directory.
[EACCES] Search permission is denied on a compo
nent of the path prefix.
[EINVAL] A bit was set in the flag argument that
is not defined for this system call, or
both the ATTR_CREATE and ATTR_REPLACE
flags bits were set.
[EFAULT] Path, attrname, or attrvalue points out
side the allocated address space of the
process.
[ELOOP] A path name lookup involved too many sym
bolic links.
[ENAMETOOLONG] The length of path exceeds {MAXPATHLEN},
or a pathname component is longer than
{MAXNAMELEN}.
attr_setf will fail if:
with the indicated filesystem object and
the ATTR_REPLACE flag bit was set.
[E2BIG] The value of the given attribute is too
large, it exceeds the maximum allowable
size of an attribute value.
[EEXIST] The attribute name given is already associ
ated with the indicated filesystem object
and the ATTR_CREATE flag bit was set.
[EINVAL] A bit was set in the flag argument that is
not defined for this system call, or both
the ATTR_CREATE and ATTR_REPLACE flags bits
were set, or fd refers to a socket, not a
file.
[EFAULT] Attrname, or attrvalue points outside the
allocated address space of the process.
[EBADF] Fd does not refer to a valid descriptor.
DIAGNOSTICS
Upon successful completion, a value of 0 is returned.
Otherwise, a value of -1 is returned and errno is set to
indicate the error.
SEE ALSO
attr(1), attr_get(3), attr_multi(3), and attr_remove(3).
Man(1) output converted with
man2html