1nbd_set_pread_initialize(3)         LIBNBD         nbd_set_pread_initialize(3)
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NAME

6       nbd_set_pread_initialize - control whether libnbd pre-initializes read
7       buffers
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SYNOPSIS

10        #include <libnbd.h>
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12        int nbd_set_pread_initialize (struct nbd_handle *h,
13                                      bool request);
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DESCRIPTION

16       By default, libnbd will pre-initialize the contents of a buffer passed
17       to calls such as nbd_pread(3) to all zeroes prior to checking for any
18       other errors, so that even if a client application passed in an
19       uninitialized buffer but fails to check for errors, it will not result
20       in a potential security risk caused by an accidental leak of prior heap
21       contents (see CVE-2022-0485 in libnbd-security(3) for an example of a
22       security hole in an application built against an earlier version of
23       libnbd that lacked consistent pre-initialization).  However, for a
24       client application that has audited that an uninitialized buffer is
25       never dereferenced, or which performs its own pre-initialization,
26       libnbd's sanitization efforts merely pessimize performance (although
27       the time spent in pre-initialization may pale in comparison to time
28       spent waiting on network packets).
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30       Calling this function with "request" set to false tells libnbd to skip
31       the buffer initialization step in read commands.
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RETURN VALUE

34       If the call is successful the function returns 0.
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ERRORS

37       On error "-1" is returned.
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39       Refer to "ERROR HANDLING" in libnbd(3) for how to get further details
40       of the error.
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VERSION

43       This function first appeared in libnbd 1.12.
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45       If you need to test if this function is available at compile time check
46       if the following macro is defined:
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48        #define LIBNBD_HAVE_NBD_SET_PREAD_INITIALIZE 1
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SEE ALSO

51       nbd_aio_pread(3), nbd_aio_pread_structured(3), nbd_create(3),
52       nbd_get_pread_initialize(3), nbd_pread(3), nbd_pread_structured(3),
53       nbd_set_strict_mode(3), libnbd(3).
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AUTHORS

56       Eric Blake
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58       Richard W.M. Jones
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61       Copyright (C) 2019-2021 Red Hat Inc.
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LICENSE

64       This library is free software; you can redistribute it and/or modify it
65       under the terms of the GNU Lesser General Public License as published
66       by the Free Software Foundation; either version 2 of the License, or
67       (at your option) any later version.
68
69       This library is distributed in the hope that it will be useful, but
70       WITHOUT ANY WARRANTY; without even the implied warranty of
71       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
72       Lesser General Public License for more details.
73
74       You should have received a copy of the GNU Lesser General Public
75       License along with this library; if not, write to the Free Software
76       Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
77       02110-1301 USA
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81libnbd-1.12.5                     2022-07-10       nbd_set_pread_initialize(3)
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