.\" Copyright (c) 2001 Chris Costello <chris@FreeBSD.org>
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.\" $FreeBSD: src/lib/libc/sys/kldsym.2,v 1.6.34.1.2.1 2009/10/25 01:10:29 kensmith Exp $
.\"
.Dd July 26, 2001
.Dt KLDSYM 2
.Os
.Sh NAME
.Nm kldsym
.Nd look up address by symbol name in a KLD
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/param.h
.In sys/linker.h
.Ft int
.Fn kldsym "int fileid" "int command" "void *data"
.Sh DESCRIPTION
The
.Fn kldsym
system call returns the address of the symbol specified in
.Fa data
in the module specified by
.Fa fileid .
If
.Fa fileid
is 0, all loaded modules are searched.
Currently, the only
.Fa command
implemented is
.Dv KLDSYM_LOOKUP .
.Pp
The
.Fa data
argument is of the following structure:
.Pp
.Bd -literal -offset indent
struct kld_sym_lookup {
    int         version;        /* sizeof(struct kld_sym_lookup) */
    char        *symname;       /* Symbol name we are looking up */
    u_long      symvalue;
    size_t      symsize;
};
.Ed
.Pp
The
.Va version
member is to be set
by the code calling
.Fn kldsym
to
.Fn sizeof "struct kld_sym_lookup" .
The next two members,
.Va version
and
.Va symname ,
are specified by the user.
The last two,
.Va symvalue
and
.Va symsize ,
are filled in by
.Fn kldsym
and contain the address associated with
.Va symname
and the size of the data it points to, respectively.
.Sh RETURN VALUES
.Rv -std kldsym
.Sh ERRORS
The
.Fn kldsym
system call will fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
Invalid value in
.Fa data->version
or
.Fa command .
.It Bq Er ENOENT
The
.Fa fileid
argument
is invalid,
or the specified symbol could not be found.
.El
.Sh SEE ALSO
.Xr kldfind 2 ,
.Xr kldfirstmod 2 ,
.Xr kldload 2 ,
.Xr kldnext 2 ,
.Xr kldunload 2 ,
.Xr modfind 2 ,
.Xr modnext 2 ,
.Xr modstat 2 ,
.Xr kld 4
.Sh HISTORY
The
.Fn kldsym
system call first appeared in
.Fx 3.0 .