NAME

       nbd_set_pread_initialize - control whether libnbd pre-initializes read buffers

SYNOPSIS

        #include <libnbd.h>

        int nbd_set_pread_initialize (
              struct nbd_handle *h, bool request
            );

DESCRIPTION

       By default, libnbd will pre-initialize the contents of a buffer passed to calls such as
       nbd_pread(3) to all zeroes prior to checking for any other errors, so that even if a
       client application passed in an uninitialized buffer but fails to check for errors, it
       will not result in a potential security risk caused by an accidental leak of prior heap
       contents (see CVE-2022-0485 in libnbd-security(3) for an example of a security hole in an
       application built against an earlier version of libnbd that lacked consistent pre-
       initialization).  However, for a client application that has audited that an uninitialized
       buffer is never dereferenced, or which performs its own pre-initialization, libnbd's
       sanitization efforts merely pessimize performance (although the time spent in pre-
       initialization may pale in comparison to time spent waiting on network packets).

       Calling this function with "request" set to false tells libnbd to skip the buffer
       initialization step in read commands.

RETURN VALUE

       If the call is successful the function returns 0.

ERRORS

       On error -1 is returned.

       Refer to "ERROR HANDLING" in libnbd(3) for how to get further details of the error.

       The following parameters must not be NULL: "h".  For more information see "Non-NULL
       parameters" in libnbd(3).

VERSION

       This function first appeared in libnbd 1.12.

       If you need to test if this function is available at compile time check if the following
       macro is defined:

        #define LIBNBD_HAVE_NBD_SET_PREAD_INITIALIZE 1

SEE ALSO

       nbd_aio_pread(3), nbd_aio_pread_structured(3), nbd_create(3), nbd_get_pread_initialize(3),
       nbd_pread(3), nbd_pread_structured(3), nbd_set_strict_mode(3), libnbd(3).

AUTHORS

       Eric Blake

       Richard W.M. Jones

COPYRIGHT

       Copyright Red Hat

LICENSE

       This library is free software; you can redistribute it and/or modify it under the terms of
       the GNU Lesser General Public License as published by the Free Software Foundation; either
       version 2 of the License, or (at your option) any later version.

       This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
       without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
       See the GNU Lesser General Public License for more details.

       You should have received a copy of the GNU Lesser General Public License along with this
       library; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
       Floor, Boston, MA 02110-1301 USA