Provided by: libcap-dev_2.17-2ubuntu1_i386 bug

NAME

       cap_copy_ext,   cap_size,  cap_copy_int  -  capability  state  external
       representation translation

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.

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.

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.

CONFORMING TO

       These  functions  are  specified  in  the  withdrawn   POSIX.1e   draft
       specification.

SEE ALSO

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

                                  2008-05-11                   CAP_COPY_EXT(3)