124 lines
3.6 KiB
Groff
124 lines
3.6 KiB
Groff
.\" $NetBSD: ksyms.4,v 1.7 2010/03/22 18:58:31 joerg Exp $
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.\"
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.\" Copyright (c) 2003 The NetBSD Foundation, Inc.
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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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"
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.Dd November 12, 2008
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.Dt KSYMS 4
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.Os
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.Sh NAME
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.Nm ksyms
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.Nd kernel symbol table interface
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.Sh SYNOPSIS
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.Cd "pseudo-device ksyms"
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.Sh DESCRIPTION
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The
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.Pa /dev/ksyms
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character device provides a read-only interface to the current
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kernel symbol table.
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It can be accessed either as a sequential
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file, where it looks like an executable file but with zero-sized
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text and data segments, or via
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.Xr ioctl 2 .
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.Pp
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.Pa /dev/ksyms
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represents the symbol table at the time when the device is opened,
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and may not change until it is closed.
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.Pp
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The in-kernel symbol manager is designed to be able to handle
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any type of symbol table.
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However, only
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.Xr elf 5
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symbol tables are currently dealt with.
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.Sh IOCTLS
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The
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.Xr ioctl 2
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command codes below are defined in
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.In sys/ksyms.h .
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.Pp
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The (third) argument to the
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.Xr ioctl 2
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should be a pointer to the type indicated.
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.Bl -tag -width indent -offset indent
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.It Dv KIOCGSIZE (int)
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Returns the total size of the current symbol table.
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This should be used when allocating a buffer to read in the
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whole symbol table to memory.
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.It Dv KIOCGVALUE (struct ksyms_gsymbol)
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Returns the value for the given symbol name in a symtab-independent
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fashion.
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.Bd -literal -offset indent
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struct ksyms_gsymbol {
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const char *kg_name;
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unsigned long *kg_value;
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};
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.Ed
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.Pp
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The struct element
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.Va kg_name
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should be set to the name of the requested value, and the address that
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.Va kg_value
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points to will receive the symbol value.
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.It Dv KIOCGSYMBOL (struct ksyms_gsymbol)
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Returns the complete symbol for the given symbol name.
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.Bd -literal -offset indent
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struct ksyms_gsymbol {
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const char *kg_name;
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void *kg_sym;
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};
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.Ed
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.Pp
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The struct element
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.Va kg_name
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should be set to the name of the requested symbol, and the found
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symbol will be written to the
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.Va kg_sym
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address.
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It is the callers responsibility to ensure that enough space
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for the symbol is allocated.
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.El
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.Sh FILES
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.Bl -tag -width /dev/ksymsX
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.It Pa /dev/ksyms
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.El
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.Sh SEE ALSO
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.Xr ioctl 2 ,
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.Xr nlist 3 ,
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.Xr elf 5
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.Sh HISTORY
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A
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.Nm
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device exists in many different operating systems.
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This implementation is modelled in function after Solaris
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.Nm .
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This
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.Nm
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driver was written by Anders Magnusson for
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.Nx .
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.Pp
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The
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.Nm
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driver first appeared in
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.Nx 2.0 .
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