Usenet 1994 January/usenetsourcesnewsgroupsinfomagicjanuary1994.iso/sources/unix/volume10/sps/part02/getcmd.c

C/C++ Source or Header | 1987-07-21 | 4.9 KB | 184 lines

# include       "sps.h"
# include       "flags.h"
# include       <h/vm.h>
# ifdef BSD42
# include    <machine/pte.h>
# else
# include       <h/pte.h>
# endif

/*
** GETCMD - Returns a character string read from a process' upage.
** This character string should represent the arguments to the current process.
*/
char    *getcmd ( p )

register struct process         *p ;

{
    register int            *ip ;
    register char           *cp ;
    register char           *cp0 ;
    unsigned                nbad ;
    struct dblock           db ;
    struct pte              ptetbl[ UPAGES + CLSIZE ] ;
    union
    {
        char            a_argc[ CLSIZE * NBPG ] ;
        int             a_argi[ CLSIZE * NBPG / sizeof( int ) ] ;
    } argbuf ;
    extern struct flags     Flg ;
    extern union userstate  User ;
    extern int              Flmem, Flswap ;
    char                    *strcat(), *strncpy(), *strsave() ;

    p->pr_csaved = 0 ;
    p->pr_upag = 0 ;
    if ( p->pr_p.p_stat == SZOMB )
        return ( "** Exit **" ) ;
    if ( !(p->pr_p.p_flag & SLOAD) && Flg.flg_o )
        return ( "** Swapped out **" ) ;
    /* Find the process' upage */
    if ( !getupage( p, ptetbl ) )
        return ( "** No upage **" ) ;
    /* Is this a system process ? */
    if ( p->pr_p.p_flag & SSYS )
        switch ( p->pr_p.p_pid )
        {
            case 0 :
                p->pr_upag = 1 ;
                return ( "Unix Swapper" ) ;
            case 2 :
                p->pr_upag = 1 ;
                return ( "Unix Pager" ) ;
            default :
                break ;
        }
    /* Fix by Alexander Dupuy <[e-mail]> */
    /* Check for lack of stack, jack! (Sun 3.0 biod's) */
    if (User.u_us.u_ssize == 0)
        goto getsysargs ;
    /* Look at the top of the upage to locate the command arguments.
       The page is loaded if the process itself is loaded and the pte
       contains is marked as valid. */
    if ( (p->pr_p.p_flag & SLOAD)
    && !ptetbl[0].pg_fod && ptetbl[0].pg_pfnum )
    {       /* If the page is loaded, read the arguments from
           physical memory. */
        memseek( Flmem, (long)ctob( ptetbl[0].pg_pfnum ) ) ;
        if ( read( Flmem, argbuf.a_argc, CLSIZE*NBPG ) != CLSIZE*NBPG )
            return ( "** Memory read error **" ) ;
    }
    else
    {       /* Otherwise the page is on the swap device */
        vstodb( 0, ctod( CLSIZE ), &User.u_us.u_smap, &db, 1 ) ;
# ifdef BSD42
        swseek( (long)dtob( db.db_base ) ) ;
# else
        swseek( (long)ctob( db.db_base ) ) ;
# endif
        if ( Flg.flg_o )
            return ( "** Swapped page **" ) ;
        if ( read( Flswap, argbuf.a_argc, CLSIZE*NBPG ) != CLSIZE*NBPG )
            return ( "** Swap device read error **" ) ;
    }
    /* Look down until the end of command arguments is found. */
    p->pr_upag = 1 ;
    p->pr_csaved = 1 ;
    ip = &argbuf.a_argi[ CLSIZE*NBPG / sizeof( int ) ] ;
    ip -= 2 ;
    while ( *--ip )
        if ( ip == &argbuf.a_argi[0] )
            goto getsysargs ;
    /* Process the command arguments, looking for nulls and unprintable
       characters. */
    cp0 = (char*)(ip + 1) ;
    if ( !*cp0 )
        cp0++ ;
    if ( *cp0 )
    {
        nbad = 0 ;
        for ( cp = cp0 ; cp < &argbuf.a_argc[ CLSIZE*NBPG ] ; cp++ )
        {
            *cp &= 0177 ;
            if ( !*cp )
            {       /* Replace nulls with spaces */
                *cp = ' ' ;
                continue ;
            }
            if ( *cp < ' ' || *cp == 0177 )
            {       /* Replace control characters with ?'s */
                if ( ++nbad > 5 )
                {
                    *cp++ = ' ' ;
                    break ;
                }
                *cp = '?' ;
                continue ;
            }
            if ( !Flg.flg_e && *cp == '=' )
            {       /* Break on an `=' if we are not interested
                   in the environment strings. */
                *cp = '\0' ;
                while ( cp > cp0 && *--cp != ' ' )
                    *cp = '\0' ;
                break ;
            }
        }
        while ( *--cp == ' ' )
            *cp = '\0' ;
        return ( strsave( cp0 ) ) ;
    }
getsysargs :
    /* If the command arguments cannot be accessed from the user's memory
       space, get the command name from the system's idea of what the
       name should be. */
    argbuf.a_argc[0] = '(' ;
    (void)strncpy( &argbuf.a_argc[1], User.u_us.u_comm,
        sizeof( User.u_us.u_comm ) ) ;
    (void)strcat( &argbuf.a_argc[0], ")" ) ;
    return ( strsave( argbuf.a_argc ) ) ;
}

/*
** VSTODB - Given a base/size pair in virtual swap area,
** return a physical base/size pair which is the
** (largest) initial, physically contiguous block.
/* This code is stolen from the kernel file /sys/sys/vm_drum.c.
*/
vstodb ( vsbase, vssize, dmp, dbp, rev )

register int                    vsbase ;
register int                    vssize;
struct dmap                     *dmp ;
register struct dblock          *dbp ;
int                             rev ;

{
    register int            blk ;
    register swblk_t        *ip ;
# ifdef BSD42
    extern struct info      Info ;
# endif

# ifdef BSD42
    blk = Info.i_dmmin ;
# else
    blk = DMMIN ;
# endif
    ip = dmp->dm_map ;
    while ( vsbase >= blk )
    {
        vsbase -= blk ;
# ifdef BSD42
        if ( blk < Info.i_dmmax )
# else
        if ( blk < DMMAX )
# endif
            blk *= 2 ;
        ip++ ;
    }
    dbp->db_size = vssize < blk - vsbase ? vssize : blk - vsbase ;
    dbp->db_base = *ip + (rev ? blk - (vsbase + dbp->db_size) : vsbase);
}