acl_get_qualifier

ACL_GET_QUALIFIER(3)      BSD Library Functions Manual      ACL_GET_QUALIFIER(3)

NAME
     acl_get_qualifier — retrieve the qualifier from an ACL entry

LIBRARY
     Linux Access Control Lists library (libacl, -lacl).

SYNOPSIS
     #include <sys/types.h>
     #include <sys/acl.h>

     void *
     acl_get_qualifier(acl_entry_t entry_d);

DESCRIPTION
     The acl_get_qualifier() function retrieves the qualifier from the ACL entry
     indicated by the argument entry_d into working storage and returns a
     pointer to that storage.

     If the value of the tag type in the ACL entry referred to by entry_d is
     ACL_USER, then the value returned by acl_get_qualifier() is a pointer to
     type uid_t.  If the value of the tag type in the ACL entry referred to by
     entry_d is ACL_GROUP, then the value returned by acl_get_qualifier() is a
     pointer to type gid_t.  If the tag type in the ACL entry referred to by
     entry_d is a tag type for which a qualifier is not supported,
     acl_get_qualifier() returns a value of (void *)NULL and the function fails.
     Subsequent operations using the returned pointer operate on an independent
     copy of the qualifier in working storage, and will not change the qualifier
     of the ACL entry.

     This function may cause memory to be allocated. The caller should free any
     releasable memory, when the new qualifier is no longer required, by calling
     acl_free() with the void * value returned by acl_get_qualifier() as an
     argument.

     The argument entry_d and any other ACL entry descriptors that refer to
     entries within the ACL containing the entry referred to by entry_d continue
     to refer to those entries. The order of all existing entries in the ACL
     containing the entry referred to by entry_d remains unchanged.

RETURN VALUE
     On success, the function returns a pointer to the tag qualifier that was
     retrieved into ACL working storage. On error, a value of (void *)NULL is
     returned and errno is set appropriately.

ERRORS
     If any of the following conditions occur, the acl_get_qualifier() function
     returns (void *)NULL and sets errno to the corresponding value:

     [EINVAL]           The argument entry_d is not a valid descriptor for an
                        ACL entry.

                        The value of the tag type in the ACL entry referenced by
                        the argument entry_d is neither ACL_USER nor ACL_GROUP.

     [ENOMEM]           The value to be returned requires more memory than is
                        allowed by the hardware or system-imposed memory
                        management constraints.

STANDARDS
     IEEE Std 1003.1e draft 17 (“POSIX.1e”, abandoned)

SEE ALSO
     acl_create_entry(3), acl_free(3), acl_get_entry(3), acl_get_permset(3),
     acl_get_tag_type(3), acl_set_permset(3), acl_set_qualifier(3),
     acl_set_tag_type(3), acl(5)

AUTHOR
     Derived from the FreeBSD manual pages written by Robert N M Watson
     <rwatson@FreeBSD.org>, and adapted for Linux by Andreas Gruenbacher
     <andreas.gruenbacher@gmail.com>.

Linux ACL                        March 23, 2002                        Linux ACL