User Access List Data Structure

struct access_list {
    unsigned char  acl_ugname[UNLEN+1];
    unsigned char  acl_ugname_pad_1;
    short          acl_access;
};

where:

• acl_ugname is an ASCIIZ string specifying a particular user name or group name.

• acl_ugname_pad_1 word-aligns the data structure components.

• acl_access specifies permission of a user name or a group name. acl_access is defined in the ACCESS.H header file as follows: ┌─────────────────────────┬───────┬────────────────────────────────────────────┐
  │ SYMBOLIC CONSTANT │ VALUE │ MEANING │
  ├─────────────────────────┼───────┼────────────────────────────────────────────┤
  │ ACCESS_NONE │ 0 │ No permission to access the resource. │
  ├─────────────────────────┼───────┼────────────────────────────────────────────┤
  │ ACCESS_READ │ 0x01 │ Permission to read data from a resource │
  │ │ │ and, by default, run the resource. │
  ├─────────────────────────┼───────┼────────────────────────────────────────────┤
  │ ACCESS_WRITE │ 0x02 │ Permission to write data to the resource. │
  ├─────────────────────────┼───────┼────────────────────────────────────────────┤
  │ ACCESS_CREATE │ 0x04 │ Permission to create an instance of the │
  │ │ │ resource (such as a file); data can be │
  │ │ │ written to the resource when the resource │
  │ │ │ is being created. │
  ├─────────────────────────┼───────┼────────────────────────────────────────────┤
  │ ACCESS_EXEC │ 0x08 │ Permission to run the resource. │
  ├─────────────────────────┼───────┼────────────────────────────────────────────┤
  │ ACCESS_DELETE │ 0x10 │ Permission to delete the resource. │
  ├─────────────────────────┼───────┼────────────────────────────────────────────┤
  │ ACCESS_ATRIB │ 0x20 │ Permission to change the attributes of a │
  │ │ │ resource (such as the date and time a file │
  │ │ │ was last changed). │
  ├─────────────────────────┼───────┼────────────────────────────────────────────┤
  │ ACCESS_PERM │ 0x40 │ Permission to change the permissions │
  │ │ │ (read, write, create, execute, and delete) │
  │ │ │ assigned to a resource for a user or │
  │ │ │ application. │
  ├─────────────────────────┼───────┼────────────────────────────────────────────┤
  │ ACCESS_ALL │ 0x7F │ Permission to read, write, create, │
  │ │ │ execute, or delete a resource, or to │
  │ │ │ change attributes or permissions. │
  ├─────────────────────────┼───────┼────────────────────────────────────────────┤
  │ ACCESS_GROUP │ 0x8000│ Permission for a particular group; if │
  │ │ │ returned, indicates that the entry is for │
  │ │ │ a group. │
  └─────────────────────────┴───────┴────────────────────────────────────────────┘