ARCHIVE_ENTRY_ACL

Section: C Library Functions (3)
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NAME

archive_entry_acl_add_entry archive_entry_acl_add_entry_w archive_entry_acl_clear archive_entry_acl_count archive_entry_acl_from_text archive_entry_acl_from_text_w archive_entry_acl_next archive_entry_acl_reset archive_entry_acl_to_text archive_entry_acl_to_text_w archive_entry_acl_types - functions for manipulating Access Control Lists in archive entry descriptions

LIBRARY

Streaming Archive Library (libarchive, -larchive)

SYNOPSIS

In archive_entry.h Ft void Fo archive_entry_acl_add_entry Fa struct archive_entry *a Fa int type Fa int permset Fa int tag Fa int qualifier Fa const char *name Fc Ft void Fo archive_entry_acl_add_entry_w Fa struct archive_entry *a Fa int type Fa int permset Fa int tag Fa int qualifier Fa const wchar_t *name Fc Ft void Fn archive_entry_acl_clear struct archive_entry *a Ft int Fn archive_entry_acl_count struct archive_entry *a int type Ft int Fo archive_entry_acl_from_text Fa struct archive_entry *a Fa const char *text Fa int type Fc Ft int Fo archive_entry_acl_from_text_w Fa struct archive_entry *a Fa const wchar_t *text Fa int type Fc Ft int Fo archive_entry_acl_next Fa struct archive_entry *a Fa int type Fa int *ret_type Fa int *ret_permset Fa int *ret_tag Fa int *ret_qual Fa const char **ret_name Fc Ft int Fn archive_entry_acl_reset struct archive_entry *a int type Ft char * Fo archive_entry_acl_to_text Fa struct archive_entry *a Fa ssize_t *len_p Fa int flags Fc Ft wchar_t * Fo archive_entry_acl_to_text_w Fa struct archive_entry *a Fa ssize_t *len_p Fa int flags Fc Ft int Fn archive_entry_acl_types struct archive_entry *a

DESCRIPTION

The ``Access Control Lists (ACLs)'' extend the standard Unix permission model. The ACL interface of libarchive supports both POSIX.1e and NFSv4 style ACLs. Use of ACLs is restricted by various levels of ACL support in operating systems, file systems and archive formats.

POSIX.1e Access Control Lists

A POSIX.1e ACL consists of a number of independent entries. Each entry specifies the permission set as a bitmask of basic permissions. Valid permissions in the Fa permset are:

ARCHIVE_ENTRY_ACL_READ ( r
ARCHIVE_ENTRY_ACL_WRITE ( w
ARCHIVE_ENTRY_ACL_EXECUTE ( x

The permissions correspond to the normal Unix permissions.

The Fa 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 specified by the name field.
ARCHIVE_ENTRY_ACL_GROUP_OBJ: The group which owns the file.
ARCHIVE_ENTRY_ACL_MASK: The maximum permissions to be obtained via group permissions.
ARCHIVE_ENTRY_ACL_OTHER: Any principal who is not the file owner or a member of the owning group.

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.

NFSv4 Access Control Lists

A NFSv4 ACL consists of multiple individual entries called Access Control Entries (ACEs).

There are four possible types of a NFSv4 ACE:

ARCHIVE_ENTRY_ACL_TYPE_ALLOW: Allow principal to perform actions requiring given permissions.
ARCHIVE_ENTRY_ACL_TYPE_DENY: Prevent principal from performing actions requiring given permissions.
ARCHIVE_ENTRY_ACL_TYPE_AUDIT: Log access attempts by principal which require given permissions.
ARCHIVE_ENTRY_ACL_TYPE_ALARM: Trigger a system alarm on access attempts by principal which require given permissions.

The Fa 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 specified by the name field.
ARCHIVE_ENTRY_ACL_GROUP_OBJ: The group which owns the file.
ARCHIVE_ENTRY_ACL_EVERYONE: Any principal who is not the file owner or a member of the owning group.

Entries with the ARCHIVE_ENTRY_ACL_USER or ARCHIVE_ENTRY_ACL_GROUP tag store the user and group name in the Fa name string and optionally the user or group ID in the Fa qualifier integer.

NFSv4 ACE permissions and flags are stored in the same Fa permset bitfield. Some permissions share the same constant and permission character but have different effect on directories than on files. The following ACE permissions are supported:

ARCHIVE_ENTRY_ACL_READ_DATA ( r: Read data (file).
ARCHIVE_ENTRY_ACL_LIST_DIRECTORY ( r: List entries (directory).
ARCHIVE_ENTRY_ACL_WRITE_DATA ( w: Write data (file).
ARCHIVE_ENTRY_ACL_ADD_FILE ( w: Create files (directory).
ARCHIVE_ENTRY_ACL_EXECUTE ( x: Execute file or change into a directory.
ARCHIVE_ENTRY_ACL_APPEND_DATA ( p: Append data (file).
ARCHIVE_ENTRY_ACL_ADD_SUBDIRECTORY ( p: Create subdirectories (directory).
ARCHIVE_ENTRY_ACL_DELETE_CHILD ( D: Remove files and subdirectories inside a directory.
ARCHIVE_ENTRY_ACL_DELETE ( d: Remove file or directory.
ARCHIVE_ENTRY_ACL_READ_ATTRIBUTES ( a: Read file or directory attributes.
ARCHIVE_ENTRY_ACL_WRITE_ATTRIBUTES ( A: Write file or directory attributes.
ARCHIVE_ENTRY_ACL_READ_NAMED_ATTRS ( R: Read named file or directory attributes.
ARCHIVE_ENTRY_ACL_WRITE_NAMED_ATTRS ( W: Write named file or directory attributes.
ARCHIVE_ENTRY_ACL_READ_ACL ( c: Read file or directory ACL.
ARCHIVE_ENTRY_ACL_WRITE_ACL ( C: Write file or directory ACL.
ARCHIVE_ENTRY_ACL_WRITE_OWNER ( o: Change owner of a file or directory.
ARCHIVE_ENTRY_ACL_SYNCHRONIZE ( s: Use synchronous I/O.

The following NFSv4 ACL inheritance flags are supported:

ARCHIVE_ENTRY_ACL_ENTRY_FILE_INHERIT ( f: Inherit parent directory ACE to files.
ARCHIVE_ENTRY_ACL_ENTRY_DIRECTORY_INHERIT ( d: Inherit parent directory ACE to subdirectories.
ARCHIVE_ENTRY_ACL_ENTRY_INHERIT_ONLY ( i: Only inherit, do not apply the permission on the directory itself.
ARCHIVE_ENTRY_ACL_ENTRY_NO_PROPAGATE_INHERIT ( n: Do not propagate inherit flags. Only first-level entries inherit ACLs.
ARCHIVE_ENTRY_ACL_ENTRY_SUCCESSFUL_ACCESS ( S: Trigger alarm or audit on successful access.
ARCHIVE_ENTRY_ACL_ENTRY_FAILED_ACCESS ( F: Trigger alarm or audit on failed access.
ARCHIVE_ENTRY_ACL_ENTRY_INHERITED ( I: Mark that ACE was inherited.

Functions

Fn archive_entry_acl_add_entry and Fn 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. An archive entry cannot contain both POSIX.1e and NFSv4 ACL entries.

Fn archive_entry_acl_clear removes all ACL entries and resets the enumeration pointer.

Fn archive_entry_acl_count counts the ACL entries that have the given type mask. Fa type can be the bitwise-or of

ARCHIVE_ENTRY_ACL_TYPE_ACCESS
ARCHIVE_ENTRY_ACL_TYPE_DEFAULT

for POSIX.1e ACLs and

ARCHIVE_ENTRY_ACL_TYPE_ALLOW
ARCHIVE_ENTRY_ACL_TYPE_DENY
ARCHIVE_ENTRY_ACL_TYPE_AUDIT
ARCHIVE_ENTRY_ACL_TYPE_ALARM

for NFSv4 ACLs. For POSIX.1e ACLs if ARCHIVE_ENTRY_ACL_TYPE_ACCESS is included and at least one extended ACL entry is found, the three non-extended ACLs are added.

Fn archive_entry_acl_from_text and Fn archive_entry_acl_from_text_w add new (or merge with existing) ACL entries from (wide) text. The argument Fa type may take one of the following values:

ARCHIVE_ENTRY_ACL_TYPE_ACCESS
ARCHIVE_ENTRY_ACL_TYPE_DEFAULT
ARCHIVE_ENTRY_ACL_TYPE_NFS4

Supports all formats that can be created with Fn archive_entry_acl_to_text or respectively Fn archive_entry_acl_to_text_w . Existing ACL entries are preserved. To get a clean new ACL from text Fn archive_entry_acl_clear must be called first. Entries prefixed with ``default:'' are treated as ARCHIVE_ENTRY_ACL_TYPE_DEFAULT unless Fa type is ARCHIVE_ENTRY_ACL_TYPE_NFS4 Invalid entries, non-parseable ACL entries and entries beginning with the `#' character (comments) are skipped.

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

Fn archive_entry_acl_reset prepare reading the list of ACL entries with Fn archive_entry_acl_next . The function returns 0 if no non-extended ACLs are found. In this case, the access permissions should be obtained by archive_entry_mode3 or set using chmod(2). Otherwise, the function returns the same value as Fn archive_entry_acl_count .

Fn archive_entry_acl_to_text and Fn archive_entry_acl_to_text_w convert the ACL entries for the given type into a (wide) string of ACL entries separated by newline. If the pointer Fa len_p is not NULL, then the function shall return the length of the string (not including the NULL terminator) in the location pointed to by Fa len_p . The Fa flag argument is a bitwise-or.

The following flags are effective only on POSIX.1e ACL:

ARCHIVE_ENTRY_ACL_TYPE_ACCESS: Output access ACLs.
ARCHIVE_ENTRY_ACL_TYPE_DEFAULT: Output POSIX.1e default ACLs.
ARCHIVE_ENTRY_ACL_STYLE_MARK_DEFAULT: Prefix each default ACL entry with the word ``default:''
ARCHIVE_ENTRY_ACL_STYLE_SOLARIS: The mask and other ACLs don not contain a double colon.

The following flags are effecive only on NFSv4 ACL:

ARCHIVE_ENTRY_ACL_STYLE_COMPACT: Do not output minus characters for unset permissions and flags in NFSv4 ACL permission and flag fields.

The following flags are effective on both POSIX.1e and NFSv4 ACL:

ARCHIVE_ENTRY_ACL_STYLE_EXTRA_ID: Add an additional colon-separated field containing the user or group id.
ARCHIVE_ENTRY_ACL_STYLE_SEPARATOR_COMMA: Separate ACL entries with comma instead of newline.

If the archive entry contains NFSv4 ACLs, all types of NFSv4 ACLs are returned. It the entry contains POSIX.1e ACLs and none of the flags ARCHIVE_ENTRY_ACL_TYPE_ACCESS or ARCHIVE_ENTRY_ACL_TYPE_DEFAULT are specified, both access and default entries are returned and default entries are prefixed with ``default:''

Fn archive_entry_acl_types get ACL entry types contained in an archive entry's ACL. As POSIX.1e and NFSv4 ACL entries cannot be mixed, this function is a very efficient way to detect if an ACL already contains POSIX.1e or NFSv4 ACL entries.

RETURN VALUES

Fn archive_entry_acl_count and Fn archive_entry_acl_reset returns the number of ACL entries that match the given type mask. For POSIX.1e ACLS 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.

Fn archive_entry_acl_from_text and Fn archive_entry_acl_from_text_w return ARCHIVE_OK if all entries were successfully parsed and ARCHIVE_WARN if one or more entries were invalid or non-parseable.

Fn archive_entry_acl_next returns ARCHIVE_OK on success, ARCHIVE_EOF if no more ACL entries exist and ARCHIVE_WARN if Fn archive_entry_acl_reset has not been called first.

Fn archive_entry_acl_to_text returns a string representing the ACL entries matching the given type and flags on success or NULL on error.

Fn archive_entry_acl_to_text_w returns a wide string representing the ACL entries matching the given type and flags on success or NULL on error.

Fn archive_entry_acl_types returns a bitmask of ACL entry types or 0 if archive entry has no ACL entries.