преобразование внешнего представления состояния возможности (capability state external representation translation)
Имя (Name)
cap_copy_ext, cap_size, cap_copy_int - capability state external
representation translation
Синопсис (Synopsis)
#include <sys/capability.h>
ssize_t cap_size(cap_t cap_p);
ssize_t cap_copy_ext(void *ext_p, cap_t cap_p, ssize_t size);
cap_t cap_copy_int(const void * ext_p);
Link with -lcap.
Описание (Description)
These functions translate between internal and external
representations of a capability state. The external
representation is an exportable, contiguous, persistent
representation of a capability state in user-managed space. The
internal representation is managed by the capability functions in
working storage.
cap_size() returns the total length (in bytes) that the
capability state in working storage identified by cap_p would
require when converted by cap_copy_ext(). This function is used
primarily to determine the amount of buffer space that must be
provided to the cap_copy_ext() function in order to hold the
capability data record created from cap_p.
cap_copy_ext() copies a capability state in working storage,
identified by cap_p, from system-managed space to user-managed
space (pointed to by ext_p) and returns the length of the
resulting data record. The size parameter represents the maximum
size, in bytes, of the resulting data record. The cap_copy_ext()
function will do any conversions necessary to convert the
capability state from the undefined internal format to an
exportable, contiguous, persistent data record. It is the
responsibility of the user to allocate a buffer large enough to
hold the copied data. The buffer length required to hold the
copied data may be obtained by a call to the cap_size() function.
cap_copy_int() copies a capability state from a capability data
record in user-managed space to a new capability state in working
storage, allocating any memory necessary, and returning a pointer
to the newly created capability state. The function initializes
the capability state and then copies the capability state from
the record pointed to by ext_p into the capability state,
converting, if necessary, the data from a contiguous, persistent
format to an undefined, internal format. Once copied into
internal format, the object can be manipulated by the capability
state manipulation functions (see cap_clear(3)). Note that the
record pointed to by ext_p must have been obtained from a
previous, successful call to cap_copy_ext() for this function to
work successfully. The caller should free any releasable memory,
when the capability state in working storage is no longer
required, by calling cap_free() with the cap_t as an argument.
Возвращаемое значение (Return value)
cap_size() returns the length required to hold a capability data
record on success, and -1 on failure.
cap_copy_ext() returns the number of bytes placed in the user
managed space pointed to by ext_p on success, and -1 on failure.
cap_copy_int() returns a pointer to the newly created capability
state in working storage on success, and NULL on failure.
On failure, errno is set to EINVAL, ENOMEM, or ERANGE.
Стандарты (Conforming to)
These functions are specified in the withdrawn POSIX.1e draft
specification.
Смотри также (See also)
libcap(3), cap_clear(3), cap_from_text(3), cap_get_file(3),
cap_get_proc(3), cap_init(3), capabilities(7)
