cap_clear(3) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | CONFORMING TO | SEE ALSO | COLOPHON

CAP_CLEAR(3)            Linux Programmer's Manual           CAP_CLEAR(3)

NAME         top

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

SYNOPSIS         top

       #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         top

       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         top

       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         top

       These functions are as per the withdrawn POSIX.1e draft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

SEE ALSO         top

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

COLOPHON         top

       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 a bug report for this manual page, send it to
       morgan@kernel.org (please put "libcap" in the Subject line).
       This page was obtained from the project's upstream Git repository
       ⟨https://git.kernel.org/pub/scm/libs/libcap/libcap.git/⟩ on
       2020-12-18.  (At that time, the date of the most recent commit
       that was found in the repository was 2020-12-12.)  If you
       discover any rendering problems in this HTML version of the page,
       or you believe there is a better or more up-to-date source for
       the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original
       manual page), send a mail to man-pages@man7.org

                               2008-05-11                   CAP_CLEAR(3)

Pages that refer to this page: cap_copy_ext(3)cap_from_text(3)cap_get_file(3)cap_get_proc(3)cap_init(3)libcap(3)capabilities(7)