Privilege Interfaces

The following table lists the interfaces for using privileges. Descriptions of some major privilege interfaces are provided after the table.

Table 2–1 Interfaces for Using Privileges

Purpose	Functions	Additional Comments
Getting and setting privilege sets	setppriv(2), getppriv(2), priv_set(3C), priv_ineffect(3C)	setppriv() and getppriv() are system calls. priv_ineffect() and priv_set() are wrappers for convenience.
Identifying and translating privileges	priv_str_to_set(3C), priv_set_to_str(3C), priv_getbyname(3C), priv_getbynum(3C), priv_getsetbyname(3C), priv_getsetbynum(3C)	These functions map the specified privilege or privilege set to a name or a number.
Manipulating privilege sets	priv_allocset(3C), priv_freeset(3C), priv_emptyset(3C), priv_fillset(3C), priv_isemptyset(3C), priv_isfullset(3C), priv_isequalset(3C), priv_issubset(3C), priv_intersect(3C), priv_union(3C), priv_inverse(3C), priv_addset(3C), priv_copyset(3C), priv_delset(3C), priv_ismember(3C)	These functions are concerned with privilege memory allocation, testing, and various set operations.
Getting and setting process flags	getpflags(2), setpflags(2)	The PRIV_AWARE process flag indicates whether the process understands privileges or runs under the superuser model. PRIV_DEBUG is used for privilege debugging.
Low-level credential manipulation	ucred_get(3C)	These routines are used for debugging, low-level system calls, and kernel calls.

setppriv(): for Setting Privileges

The main function for setting privileges is setppriv(), which has the following syntax:

int setppriv(priv_op_t op, priv_ptype_t which, \
const priv_set_t *set);

op represents the privilege operation that is to be performed. The op parameter has one of three possible values:

• PRIV_ON – Adds the privileges that are specified by the set variable to the set type that is specified by which

• PRIV_OFF – Removes the privileges that are specified by the set variable from the set type that is specified by which

• PRIV_SET – Uses the privileges that are specified by the set variable to replace privileges in the set type that is specified by which

which specifies the type of privilege set to be changed, as follows:

• PRIV_PERMITTED

• PRIV_EFFECTIVE

• PRIV_INHERITABLE

• PRIV_LIMIT

set specifies the privileges to be used in the change operation.

In addition, a convenience function is provided: priv_set().

priv_str_to_set() for Mapping Privileges

These functions are convenient for mapping privilege names with their numeric values. priv_str_to_set() is a typical function in this family. priv_str_to_set() has the following syntax:

priv_set_t *priv_str_to_set(const char *buf, const char *set, \
const char **endptr);

priv_str_to_set() takes a string of privilege names that are specified in buf. priv_str_to_set() returns a set of privilege values that can be combined with one of the four privilege sets. **endptr can be used to debug parsing errors. Note that the following keywords can be included in buf:

• “all” indicates all defined privileges. “all,!priv_name,...” enables you to specify all privileges except the indicated privileges.

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  Note –

  Constructions that use “priv_set, “!priv_name,...” subtract the specified privilege from the specified set of privileges. Do not use “!priv_name,...” without first specifying a set because with no privilege set to subtract from, the construction subtracts the specified privileges from an empty set of privileges and effectively indicates no privileges.

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• “none” indicates no privileges.

• “basic” indicates the set of privileges that are required to perform operations that are traditionally granted to all users on login to a standard UNIX operating system.