110 lines
3.2 KiB
Groff
110 lines
3.2 KiB
Groff
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.\" $NetBSD: mremap.2,v 1.3 2008/02/16 17:45:39 tnn Exp $
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.\"
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.\" Copyright (c) 2007 Thomas Klausner and Joerg Sonnenberger
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" ------------------------------------------------------------
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.Dd February 14, 2008
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.Dt MREMAP 2
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.Os
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.Sh NAME
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.Nm mremap
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.Nd re-map a virtual memory address
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.\" ------------------------------------------------------------
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In sys/mman.h
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.Ft void *
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.Fn mremap "void *oldp" "size_t oldsize" "void *newp" "size_t newsize" \
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"int flags"
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.\" ------------------------------------------------------------
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.Sh DESCRIPTION
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The
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.Fn mremap
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function resizes the mapped range (see
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.Xr mmap 2 )
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starting at
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.Ar oldp
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and having size
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.Ar oldsize
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to
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.Ar newsize .
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The following arguments can be
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.Dv OR Ap ed
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together in the
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.Ar flags
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argument:
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.Bl -tag -width XXMAPXALIGNEDXnXX
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.It Dv MAP_ALIGNED Ns Pq Ar n
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The allocation should be aligned to the given boundary, i.e. ensure
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that the lowest
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.Ar n
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bits of the address are zero.
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The parameter
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.Ar n
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should be the base 2 logarithm of the desired alignment (e.g., to
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request alignment to 16K, use 14 as the value for n).
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The alignment must be equal to or greater than the platform's page
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size as returned by
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.Xr sysconf 3
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with the
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.Dv _SC_PAGESIZE
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request.
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.It Dv MAP_FIXED
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.Ar newp
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is tried and
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.Fn mremap
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fails if that address can't be used as new base address for the range.
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Otherwise,
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.Ar oldp
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and
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.Ar newp
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are used as hints for the position, factoring in the given alignment.
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.El
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.Sh RETURN VALUES
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.Fn mremap
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returns the new address or
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.Dv MAP_FAILED ,
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if the remap failed.
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.Sh HISTORY
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The
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.Fn mremap
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system call appeared in
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.Nx 5.0 .
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It was based on the code that supports
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.Fn mremap
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compatibility for Linux binaries.
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.Sh COMPATIBILITY
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The semantics of
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.Fn mremap
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differ from the one provided by glibc on Linux in that the
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.Ar newp
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argument was added and a different set of
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.Ar flags
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are implemented.
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.Sh SEE ALSO
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.Xr mmap 2 ,
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.Xr munmap 2
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