keyctl_describe()
describes the attributes of a key as a NUL-terminated string.
The caller must have
view
permission on a key to be able to get a description of it.
buffer
and
buflen
specify the buffer into which the key description will be placed. If the
buffer is too small, the full size of the description will be returned, and no
copy will take place.
keyctl_describe_alloc()
is similar to
keyctl_describe()
except that it allocates a buffer big enough to hold the description and
places the description in it. If successful, A pointer to the buffer is
placed in
*_buffer.
The caller must free the buffer.
The description will be a string of format:
``%s;%d;%d;%08x;%s''
where the arguments are: key type name, key UID, key GID, key permissions mask
and key description.
NOTE!
The key description will not contain any semicolons, so that should be
separated out by working backwards from the end of the string. This permits
extra information to be inserted before it by later versions of the kernel
simply by inserting more semicolon-terminated substrings.
RETURN VALUE
On success
keyctl_describe()
returns the amount of data placed into the buffer. If the buffer was too
small, then the size of buffer required will be returned, but no data will be
transferred. On error, the value
-1
will be returned and errno will have been set to an appropriate error.
On success
keyctl_describe_alloc()
returns the amount of data in the buffer, less the NUL terminator. On error, the value
-1
will be returned and errno will have been set to an appropriate error.
ERRORS
ENOKEY
The key specified is invalid.
EKEYEXPIRED
The key specified has expired.
EKEYREVOKED
The key specified had been revoked.
EACCES
The key exists, but is not
viewable
by the calling process.
LINKING
This is a library function that can be found in
libkeyutils.
When linking,
-lkeyutils
should be specified to the linker.
