The acltomode() function converts an ACL pointed to by aclbufp into the permission bits buffer pointed to by modep. If the USER_OBJ ACL entry, GROUP_OBJ ACL entry, or the OTHER_OBJ ACL entry cannot be found in the ACL buffer, then the function fails with errno set to EINVAL.

The USER_OBJ ACL entry permission bits are copied to the file owner class bits in the permission bits buffer. The OTHER_OBJ ACL entry permission bits are copied to the file other class bits in the permission bits buffer. If there is a CLASS_OBJ (ACL mask) entry, the CLASS_OBJ ACL entry permission bits are copied to the file group class bits in the permission bits buffer. Otherwise, the GROUP_OBJ ACL entry permission bits are copied to the file group class bits in the permission bits buffer.

The aclfrommode() function converts the permission bits pointed to by modep into an ACL pointed to by aclbufp. If the USER_OBJ ACL entry, GROUP_OBJ ACL entry, or the OTHER_OBJ ACL entry cannot be found in the ACL buffer, the function fails with errno set to EINVAL.

The file owner class bits from the permission bits buffer are copied to the USER_OBJ ACL entry. The file other class bits from the permission bits buffer are copied to the OTHER_OBJ ACL entry. If there is a CLASS_OBJ (ACL mask) entry, the file group class bits from the permission bits buffer are copied to the CLASS_OBJ ACL entry, and the GROUP_OBJ ACL entry is not modified. Otherwise, the file group class bits from the permission bits buffer are copied to the GROUP_OBJ ACL entry.

The nentries argument represents the number of ACL entries in the buffer pointed to by aclbufp.

Upon successful completion, the function returns 0. Otherwise, it returns -1 and sets errno to indicate the error.

See attributes(5) for descriptions of the following attributes:

acl(2), attributes(5)