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>
11
12        int nbd_set_pread_initialize (
13              struct nbd_handle *h, bool request
14            );
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DESCRIPTION

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

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

38       On error -1 is returned.
39
40       Refer to "ERROR HANDLING" in libnbd(3) for how to get further details
41       of the error.
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43       The following parameters must not be NULL: "h".  For more information
44       see "Non-NULL parameters" in libnbd(3).
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VERSION

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

55       nbd_aio_pread(3), nbd_aio_pread_structured(3), nbd_create(3),
56       nbd_get_pread_initialize(3), nbd_pread(3), nbd_pread_structured(3),
57       nbd_set_strict_mode(3), libnbd(3).
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AUTHORS

60       Eric Blake
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62       Richard W.M. Jones
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65       Copyright Red Hat
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LICENSE

68       This library is free software; you can redistribute it and/or modify it
69       under the terms of the GNU Lesser General Public License as published
70       by the Free Software Foundation; either version 2 of the License, or
71       (at your option) any later version.
72
73       This library is distributed in the hope that it will be useful, but
74       WITHOUT ANY WARRANTY; without even the implied warranty of
75       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
76       Lesser General Public License for more details.
77
78       You should have received a copy of the GNU Lesser General Public
79       License along with this library; if not, write to the Free Software
80       Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
81       02110-1301 USA
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85libnbd-1.18.1                     2023-10-31       nbd_set_pread_initialize(3)
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