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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | CONFORMING TO | SEE ALSO | COLOPHON |
CAP_CLEAR(3) Linux Programmer's Manual CAP_CLEAR(3)
cap_clear, cap_clear_flag, cap_get_flag, cap_set_flag, cap_compare -
capability data object manipulation
#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.
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.
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.
These functions are as per the withdrawn POSIX.1e draft
specification. cap_clear_flag() and cap_compare() are Linux
extensions.
libcap(3), cap_copy_ext(3), cap_from_text(3), cap_get_file(3),
cap_get_proc(3), cap_init(3), capabilities(7)
This page is part of the libcap (capabilities commands and library)
project. Information about the project can be found at
⟨https://git.kernel.org/cgit/linux/kernel/git/morgan/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
⟨git://git.kernel.org/pub/scm/linux/kernel/git/morgan/libcap.git⟩ on
2017-07-05. If you discover any rendering problems in this HTML ver‐
sion 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 man‐
ual 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)