Technical Reference: Base Operating System and Extensions, Volume 1

acl_chg or acl_fchg Subroutine

Purpose

Changes the access control information on a file.

Library

Security Library (libc.a)

Syntax

#include <sys/access.h>

int acl_chg (Path, How, Mode, Who) char * Path; int How; int Mode; int Who;

int acl_fchg (FileDescriptor, How, Mode, Who) int FileDescriptor; int How; int Mode; int Who;

Description

The acl_chg and acl_fchg subroutines modify the access control information of a specified file.

Parameters

FileDescriptor	Specifies the file descriptor of an open file.
How	Specifies how the permissions are to be altered for the affected entries of the Access Control List (ACL). This parameter takes one of the following values: ACC_PERMIT Allows the types of access included in the Mode parameter. ACC_DENY Denies the types of access included in the Mode parameter. ACC_SPECIFY Grants the access modes included in the Mode parameter and restricts the access modes not included in the Mode parameter.
Mode	Specifies the access modes to be changed. The Mode parameter is a bit mask containing zero or more of the following values: R_ACC Allows read permission. W_ACC Allows write permission. X_ACC Allows execute or search permission.
Path	Specifies a pointer to the path name of a file.
Who	Specifies which entries in the ACL are affected. This parameter takes one of the following values: ACC_OBJ_OWNER Changes the owner entry in the base ACL. ACC_OBJ_GROUP Changes the group entry in the base ACL. ACC_OTHERS Changes all entries in the ACL except the base entry for the owner. ACC_ALL Changes all entries in the ACL.

Return Values

On successful completion, the acl_chg and acl_fchg subroutines return a value of 0. Otherwise, a value of -1 is returned and the errno global variable is set to indicate the error.

Error Codes

The acl_chg subroutine fails and the access control information for a file remains unchanged if one or more of the following are true:

EACCES	Search permission is denied on a component of the Path prefix.
EFAULT	The Path parameter points to a location outside of the allocated address space of the process.
ELOOP	Too many symbolic links were encountered in translating the Path parameter.
ENAMETOOLONG	A component of the Path parameter exceeded 255 characters, or the entire Path parameter exceeded 1023 characters.
ENOENT	A component of the Path does not exist or has the disallow truncation attribute (see the ulimit subroutine).
ENOENT	The Path parameter was null.
ENOENT	A symbolic link was named, but the file to which it refers does not exist.
ENOTDIR	A component of the Path prefix is not a directory.
ESTALE	The process' root or current directory is located in a virtual file system that has been unmounted.

The acl_fchg subroutine fails and the file permissions remain unchanged if the following is true:

EBADF

The FileDescriptor value is not valid.

The acl_chg or acl_fchg subroutine fails and the access control information for a file remains unchanged if one or more of the following are true:

EINVAL	The How parameter is not one of ACC_PERMIT, ACC_DENY, or ACC_SPECIFY.
EINVAL	The Who parameter is not ACC_OWNER, ACC_GROUP, ACC_OTHERS, or ACC_ALL.
EROFS	The named file resides on a read-only file system.

The acl_chg or acl_fchg subroutine fails and the access control information for a file remains unchanged if one or more of the following are true:

EIO	An I/O error occurred during the operation.
EPERM	The effective user ID does not match the ID of the owner of the file and the invoker does not have root user authority.

If Network File System (NFS) is installed on your system, the acl_chg and acl_fchg subroutines can also fail if the following is true:

ETIMEDOUT

The connection timed out.

Implementation Specifics

These subroutines are part of Base Operating System (BOS) Runtime.

Related Information

The acl_get (acl_get or acl_fget Subroutine) subroutine, acl_put (acl_put or acl_fput Subroutine) subroutine, acl_set (acl_set or acl_fset Subroutine) subroutine, chacl (chacl or fchacl Subroutine) subroutine, chmod (chmod or fchmod Subroutine) subroutine, stat subroutine, statacl subroutine.

The aclget command, aclput command, chmod command.

List of Security and Auditing Subroutines and Subroutines Overview in AIX 5L Version 5.1 General Programming Concepts: Writing and Debugging Programs.