Provided by: libcap-dev_2.21-2_i386 bug

NAME

       cap_clear,  cap_clear_flag,  cap_get_flag,  cap_set_flag, cap_compare -
       capability data object manipulation

SYNOPSIS

       #include <sys/capability.h>

       int cap_clear(cap_t cap_p);

       int cap_clear_flag(cap_t cap_p, cap_flag_t flag);

       int cap_get_flag(cap_t cap_p, cap_value_t cap,
                        cap_flag_t flag, cap_flag_value_t *value_p);

       int cap_set_flag(cap_t cap_p, cap_flag_t flag, int ncap,
                        const cap_value_t *caps, cap_flag_value_t value);

       int cap_compare(cap_t cap_a, cap_t cap_b);

       Link with -lcap.

DESCRIPTION

       These functions work on a capability state held in working storage.   A
       cap_t  holds  information  about  the capabilities in each of the three
       sets, Permitted, Inheritable, and Effective.  Each capability in a  set
       may be clear (disabled, 0) or set (enabled, 1).

       These functions work with the following data types:

       cap_value_t       identifies a capability, such as CAP_CHOWN.

       cap_flag_t        identifies  one  of the three flags associated with a
                         capability (i.e., it  identifies  one  of  the  three
                         capability  sets).   Valid  values  for this type are
                         CAP_EFFECTIVE, CAP_INHERITABLE or CAP_PERMITTED.

       cap_flag_value_t  identifies the setting  of  a  particular  capability
                         flag  (i.e,  the  value  of  a  capability in a set).
                         Valid values for  this  type  are  CAP_CLEAR  (0)  or
                         CAP_SET (1).

       cap_clear()   initializes  the  capability  state  in  working  storage
       identified by cap_p so that all capability flags are cleared.

       cap_clear_flag() clears  all  of  the  capabilities  of  the  specified
       capability flag, flag.

       cap_get_flag()  obtains the current value of the capability flag, flag,
       of the capability, cap, from the capability state identified  by  cap_p
       and places it in the location pointed to by value_p.

       cap_set_flag()  sets  the  flag,  flag, of each capability in the array
       caps in the  capability  state  identified  by  cap_p  to  value.   The
       argument,  ncap,  is  used to specify the number of capabilities in the
       array, caps.

       cap_compare() compares two full capability sets and, in the  spirit  of
       memcmp(),  returns  zero  if  the  two capability sets are identical. A
       positive return value, status, indicates there is a difference  between
       them.  The  returned  value  carries further information about which of
       three  sets,  cap_flag_t  flag,   differ.   Specifically,   the   macro
       CAP_DIFFERS (status, flag) evaluates to non-zero if the returned status
       differs in its flag components.

RETURN VALUE

       cap_clear(),  cap_clear_flag(),   cap_get_flag()   cap_set_flag()   and
       cap_compare()  return  zero on success, and -1 on failure. Other return
       values for cap_compare() are described above.

       On failure, errno  is  set  to  EINVAL,  indicating  that  one  of  the
       arguments is invalid.

CONFORMING TO

       These  functions are as per the withdrawn POSIX.1e draft specification.
       cap_clear_flag() and cap_compare() are Linux extensions.

SEE ALSO

       libcap(3),    cap_copy_ext(3),    cap_from_text(3),    cap_get_file(3),
       cap_get_proc(3), cap_init(3), capabilities(7)

                                  2008-05-11                      CAP_CLEAR(3)