archive_entry_acl man page

archive_entry_acl_add_entry, archive_entry_acl_add_entry_w, archive_entry_acl_clear, archive_entry_acl_count, archive_entry_acl_next, archive_entry_acl_next_w, archive_entry_acl_reset, archive_entry_acl_text_w — functions for manipulating Access Control Lists in archive entry descriptions

Library

Streaming Archive Library (libarchive, -larchive)

Synopsis

#include <archive_entry.h>

void
archive_entry_acl_add_entry(struct archive_entry *a, int type, int permset, int tag, int qualifier, const char *name);

void
archive_entry_acl_add_entry_w(struct archive_entry *a, int type, int permset, int tag, int qualifier, const wchar_t *name);

void
archive_entry_acl_clear(struct archive_entry *a);

int
archive_entry_acl_count(struct archive_entry *a, int type);

int
archive_entry_acl_next(struct archive_entry *a, int type, int *ret_type, int *ret_permset, int *ret_tag, int *ret_qual, const char **ret_name);

int
archive_entry_acl_next_w(struct archive_entry *a, int type, int *ret_type, int *ret_permset, int *ret_tag, int *ret_qual, const wchar_t **ret_name);

int
archive_entry_acl_reset(struct archive_entry *a, int type);

const wchar_t *
archive_entry_acl_text_w(struct archive_entry *a, int flags);

Description

An “Access Control List” is a generalisation of the classic Unix permission system. The ACL interface of libarchive is derived from the POSIX.1e draft, but restricted to simplify dealing with practical implementations in various Operating Systems and archive formats.

An ACL consists of a number of independent entries. Each entry specifies the permission set as bitmask of basic permissions. Valid permissions are:

ARCHIVE_ENTRY_ACL_EXECUTE
ARCHIVE_ENTRY_ACL_WRITE
ARCHIVE_ENTRY_ACL_READ

The permissions correspond to the normal Unix permissions.

The tag specifies the principal to which the permission applies. Valid values are:

ARCHIVE_ENTRY_ACL_USER
The user specified by the name field.
ARCHIVE_ENTRY_ACL_USER_OBJ
The owner of the file.
ARCHIVE_ENTRY_ACL_GROUP
The group specied by the name field.
ARCHIVE_ENTRY_ACL_GROUP_OBJ
The group who owns the file.
ARCHIVE_ENTRY_ACL_MASK
The maximum permissions to be obtained via group permissions.
ARCHIVE_ENTRY_ACL_OTHER
Any principal who doesn't have a user or group entry.

The principals ARCHIVE_ENTRY_ACL_USER_OBJ, ARCHIVE_ENTRY_ACL_GROUP_OBJ and ARCHIVE_ENTRY_ACL_OTHER are equivalent to user, group and other in the classic Unix permission model and specify non-extended ACL entries.

All files have an access ACL (ARCHIVE_ENTRY_ACL_TYPE_ACCESS). This specifies the permissions required for access to the file itself. Directories have an additional ACL (ARCHIVE_ENTRY_ACL_TYPE_DEFAULT), which controls the initial access ACL for newly created directory entries.

archive_entry_acl_add_entry() and archive_entry_acl_add_entry_w() add a single ACL entry. For the access ACL and non-extended principals, the classic Unix permissions are updated.

archive_entry_acl_clear() removes all ACL entries and resets the enumeration pointer.

archive_entry_acl_count() counts the ACL entries that have the given type mask. type can be the bitwise-or of ARCHIVE_ENTRY_ACL_TYPE_ACCESS and ARCHIVE_ENTRY_ACL_TYPE_DEFAULT. If ARCHIVE_ENTRY_ACL_TYPE_ACCESS is included and at least one extended ACL entry is found, the three non-extened ACLs are added.

archive_entry_acl_next() and archive_entry_acl_next_w() return the next entry of the ACL list. This functions may only be called after archive_entry_acl_reset() has indicated the presence of extended ACL entries.

archive_entry_acl_reset() prepare reading the list of ACL entries with archive_entry_acl_next() or archive_entry_acl_next_w(). The function returns either 0, if no non-extended ACLs are found. In this case, the access permissions should be obtained by archive_entry_mode(3) or set using chmod(2). Otherwise, the function returns the same value as archive_entry_acl_count().

archive_entry_acl_text_w() converts the ACL entries for the given type mask into a wide string. In addition to the normal type flags, ARCHIVE_ENTRY_ACL_STYLE_EXTRA_ID and ARCHIVE_ENTRY_ACL_STYLE_MARK_DEFAULT can be specified to further customize the result. The returned long string is valid until the next call to archive_entry_acl_clear(), archive_entry_acl_add_entry(), archive_entry_acl_add_entry_w() or archive_entry_acl_text_w().

Return Values

archive_entry_acl_count() and archive_entry_acl_reset() returns the number of ACL entries that match the given type mask. If the type mask includes ARCHIVE_ENTRY_ACL_TYPE_ACCESS and at least one extended ACL entry exists, the three classic Unix permissions are counted.

archive_entry_acl_next() and archive_entry_acl_next_w() return ARCHIVE_OK on success, ARCHIVE_EOF if no more ACL entries exist and ARCHIVE_WARN if archive_entry_acl_reset() has not been called first.

archive_entry_text_w() returns a wide string representation of the ACL entrise matching the given type mask. The returned long string is valid until the next call to archive_entry_acl_clear(), archive_entry_acl_add_entry(), archive_entry_acl_add_entry_w() or archive_entry_acl_text_w().

See Also

archive_entry(3) libarchive(3),

Bugs

ARCHIVE_ENTRY_ACL_STYLE_EXTRA_ID and ARCHIVE_ENTRY_ACL_STYLE_MARK_DEFAULT are not documented.

Referenced By

archive_entry(3), archive_entry_perms(3), archive_entry_stat(3).

February 2, 2012