common/misc/fs3d.c

	fs3d.c revision 7c2fbfb345896881c631598ee3852ce9ce33fb07
/***********************************************************************
*                                                                      *
*               This software is part of the ast package               *
*          Copyright (c) 1985-2008 AT&T Intellectual Property          *
*                      and is licensed under the                       *
*                  Common Public License, Version 1.0                  *
*                    by AT&T Intellectual Property                     *
*                                                                      *
*                A copy of the License is available at                 *
*            http://www.opensource.org/licenses/cpl1.0.txt             *
*         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
*                                                                      *
*              Information and Software Systems Research               *
*                            AT&T Research                             *
*                           Florham Park NJ                            *
*                                                                      *
*                 Glenn Fowler <gsf@research.att.com>                  *
*                  David Korn <dgk@research.att.com>                   *
*                   Phong Vo <kpv@research.att.com>                    *
*                                                                      *
***********************************************************************/
#pragma prototyped
/*
 * Glenn Fowler
 * AT&T Bell Laboratories
 *
 * 3d fs operations
 * only active for non-shared 3d library
 */

#include <ast.h>
#include <fs3d.h>

int
fs3d(register int op)
{
    register int    cur;
    register char*  v;
    char        val[sizeof(FS3D_off) + 8];

    static int  fsview;
    static char on[] = FS3D_on;
    static char off[] = FS3D_off;

    if (fsview < 0)
        return 0;

    /*
     * get the current setting
     */

    if (!fsview && (!getenv("LD_PRELOAD") || mount("", "", 0, NiL)))
        goto nope;
    if (FS3D_op(op) == FS3D_OP_INIT && mount(FS3D_init, NiL, FS3D_VIEW, NiL))
        goto nope;
    if (mount(on, val, FS3D_VIEW|FS3D_GET|FS3D_SIZE(sizeof(val)), NiL))
        goto nope;
    if (v = strchr(val, ' '))
        v++;
    else
        v = val;
    if (!strcmp(v, on))
        cur = FS3D_ON;
    else if (!strncmp(v, off, sizeof(off) - 1) && v[sizeof(off)] == '=')
        cur = FS3D_LIMIT((int)strtol(v + sizeof(off) + 1, NiL, 0));
    else
        cur = FS3D_OFF;
    if (cur != op)
    {
        switch (FS3D_op(op))
        {
        case FS3D_OP_OFF:
            v = off;
            break;
        case FS3D_OP_ON:
            v = on;
            break;
        case FS3D_OP_LIMIT:
            sfsprintf(val, sizeof(val), "%s=%d", off, FS3D_arg(op));
            v = val;
            break;
        default:
            v = 0;
            break;
        }
        if (v && mount(v, NiL, FS3D_VIEW, NiL))
            goto nope;
    }
    fsview = 1;
    return cur;
 nope:
    fsview = -1;
    return 0;
}