acl_get_entry

Library

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

Synopsis

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

int
acl_get_entry(acl_t acl, int entry_id, acl_entry_t *entry_p);

Description

The acl_get_entry() function obtains a descriptor for an ACL entry as specified by entry_id within the ACL indicated by the argument acl. If the value of entry_id is ACL_FIRST_ENTRY, then the function returns in entry_p a descriptor for the first ACL entry within acl. If the value of entry_id is ACL_NEXT_ENTRY, then the function returns in entry_p a descriptor for the next ACL entry within acl.

If a call is made to acl_get_entry() with entry_id set to ACL_NEXT_ENTRY when there has not been either an initial successful call to acl_get_entry(), or a previous successful call to acl_get_entry() following a call to acl_calc_mask(), acl_copy_int(), acl_create_entry(), acl_delete_entry(), acl_dup(), acl_from_text(), acl_get_fd(), acl_get_file(), acl_set_fd(), acl_set_file(), or acl_valid(), then the effect is unspecified.

Calls to acl_get_entry() do not modify any ACL entries. Subsequent operations using the returned ACL entry descriptor operate on the ACL entry within the ACL in working storage. The order of all existing entries in the ACL remains unchanged. Any existing ACL entry descriptors that refer to entries within the ACL continue to refer to those entries. Any existing ACL pointers that refer to the ACL referred to by acl continue to refer to the ACL.

Return Value

If the function successfully obtains an ACL entry, the function returns a value of 1. If the ACL has no ACL entries, the function returns the value 0. If the value of entry_id is ACL_NEXT_ENTRY and the last ACL entry in the ACL has already been returned by a previous call to acl_get_entry(), the function returns the value 0 until a successful call with an entry_id of ACL_FIRST_ENTRY is made. Otherwise, the value -1 is returned and errno is set to indicate the error.

Errors

If any of the following conditions occur, the acl_get_entry() function returns -1 and sets errno to the corresponding value:

[EINVAL]

The argument acl_p is not a valid pointer to an ACL.

The argument entry_id is neither ACL_NEXT_ENTRY nor ACL_FIRST_ENTRY.

Standards

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

See Also

acl_calc_mask(3), acl_create_entry(3), acl_copy_entry(3), acl_delete_entry(3), acl_get_file(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 ⟨a.gruenbacher@bestbits.at⟩.

Referenced By

acl(5), acl_calc_mask(3), acl_copy_entry(3), acl_copy_int(3), acl_delete_entry(3), acl_dup(3), acl_from_text(3), acl_get_fd(3), acl_get_file(3), acl_get_qualifier(3), acl_get_tag_type(3).