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_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
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_tflag, differ. Specifically, the macro
CAP_DIFFERS (status, flag) evaluates to non-zero if the returned
status differs in its flag components.
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.
This page is part of the libcap (capabilities commands and library)
project. Information about the project can be found at
⟨https://git.kernel.org/pub/scm/libs/libcap/libcap.git/⟩. If you have
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(please put "libcap" in the Subject line). This page was obtained
from the project's upstream Git repository
2020-08-13. (At that time, the date of the most recent commit that
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