#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);
DescriptionThe attr_set and attr_setf
functions provide a way to create 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 filesystem object, otherwise
create an attribute with the given name and value. This flag is used to
implement 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 given name does not already
exist on the indicated 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 associated 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 associated 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 component 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 outside
the allocated address space of the process. [ELOOP] A path name lookup
involved too many symbolic links. [ENAMETOOLONG] The length of path exceeds
{MAXPATHLEN}, or a pathname component is longer than {MAXNAMELEN}. attr_setf
will fail if:
[ENOATTR] The attribute name given is not associated 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 associated 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. DiagnosticsOn success,
zero is returned. On error, -1 is returned, and errno is set appropriately.
See Alsoattr(1), attr_get(3), attr_multi(3), and attr_remove(3).