Simtel MSDOS 1992 June/SIMTEL_0692.cdr/msdos/dirutl/chmod2.arc/CHMOD.C

C/C++ Source or Header | 1987-01-16 | 5.1 KB | 204 lines

/*//////////////////////////////////////////////////////////////////////////
// c h m o d . c
////////////////
CHMOD(1)                    MS DOS USER COMMANDS                    CHMOD(1)

NAME
        chmod

SYNOPSIS
        chmod [=+-][r][h][s][a] file ...

DESCRIPTION

         Changes the attributes of 'file'. The file attributes can either
    be set (=),  or attributes can  be added (+)  or removed (-) from the
    the current attribute. If no attributes  are specified, then the file
    is marked 'normal' i.e. no attributes set except the archive bit.

Newman Lab        [e-mail]
Cornell Univ      [e-mail]
Ithaca NY 14853

I retain all rights to this program.         (c) Gene Cohler, January 1987
**************************************************************************/
/*
 *  N.B. I use tab set to 4
 *
 * History :
 *
 *    Feb 14 1986    - Version 1 peeks out the window ...
 *
 * Modified
 *     :- August 1 1986
 *            1) Looks more like unix version - choose to set attribute
 *               = or - or + to set or remove or add.
 *             2) Talks a little more .. old age maybe !
 *     :- January 1987
 *            1) Default works a little better - now Archive set is default.
 *                Also chmod file will set the archive bit only.
 *            2) Ready to hit the streets with v 1.0
 *            3) Directory Bugfix made, +- didnt work only =. Fixed.
 *****************************************************************************
 * Written in Microsoft C v 4.0. Should be linked together with ssetargv.obj
 * included in the standard library
 *****************************************************************************/
#include <stdio.h>
#include <dos.h>

#define        SET        1
#define        GET        0
#define        SUBDIR    0x10
#define     ARCHIVE    0x20

main(argc,argv)
    int argc;
    char **argv;
    {
    unsigned attrib = ARCHIVE ;
    unsigned oldattrib=0 ;
    unsigned newattrib=0 ;
    static int what='=' ;

    register unsigned i  ;
    register unsigned notfile ;

    if( argc == 1 )
        error("No file specified");

   /*
    * Find what attributes are being called for
    */

    for(i=1;i<argc;i++)
        {
        switch( argv[i][0] )
            {
            case '-' :
            case '+' :
            case '=' :
                parse(&attrib, argv[i], &what);
                notfile = i ;
            }
        }

   /*
      * Now set em one by one
    */

    for( i=1; i<argc ; i++)
        {
        if( i != notfile )
            {
            oldattrib = mode( argv[i], attrib, GET) ;
            /*
             * Directory attrib not settable
             */
            if (oldattrib & SUBDIR)
                oldattrib = (oldattrib & (~SUBDIR) ) & 0xff ;
            switch( what )
                {
                case '=' :
                    newattrib = attrib ;
                    break;
                case '+' :
                    if(oldattrib == -1)
                        {
                        fprintf(stderr,"Error finding mode of %s\n",argv[i]);
                        continue ;
                        }
                    newattrib = oldattrib | attrib ;
                    break ;
                case '-' :
                    if(oldattrib  == -1)
                        {
                        fprintf(stderr,"Error finding mode of %s\n",argv[i]);
                        continue ;
                        }
                    newattrib = (oldattrib & (~attrib))  & 0xff;
                    break;
                default :
                    error("No mode qualifier given");
                }
            if((oldattrib = mode( argv[i], newattrib, SET)) == -1)
                {
                fprintf(stderr,"Error setting mode of %s\n",argv[i]);
                continue ;
                }
            }
        }
    }


/********************************************
 * mode.c  - change/get the mode - DOS call *
 * action is 1 to set the mode :
 * action is 0 to get the mode ;
 *****************************************/

#define  SYSCALL    0x21

    int
mode(name, attrib, action )
    unsigned char name[]       ;
    unsigned attrib                 ;
    int action ;
    {
    struct SREGS segregs     ;
    union REGS regs         ;

    if( action == SET)    regs.x.ax = 0x4301     ;/* Set up for a chmod */
    else                regs.x.ax = 0x4300    ;
    regs.x.cx = attrib      ;
    segread(&segregs)       ;                       /* get current ds value */
    regs.x.dx = (unsigned int) name;             /* name is in ds:dx */
    regs.x.cflag = 0        ;                    /* Make sure flag is zeroed */

    int86x(SYSCALL, ®s, ®s, &segregs) ;      /* Do it */

    if (regs.x.cflag)    return (-1) ;            /* Return error */
    else                 return (regs.x.cx);        /* Return attrib */
    }

/*
 *  Attributes used in the file descriptor
 */

#define    NORMAL        0x00
#define    READONLY    0x01
#define    HIDDEN        0x02
#define    SYSTEM        0x04
#define    VOLUME        0x08

parse( attrib, arg, what)
    unsigned *attrib ;
    char arg[]   ;
    int *what    ;
    {
    register i ;
    unsigned numargs = strlen(arg) ;
    *attrib = NORMAL ;
    *what = arg[0] ;

    if (numargs == 1)        /* Set Archive as Default */
        {
        *attrib = ARCHIVE ;
        return ;
        }
    for(i=1; i<numargs ; i++)
        {
        if( toupper(arg[i]) == 'R' )    *attrib |= READONLY ;
        if( toupper(arg[i]) == 'S' )    *attrib |= SYSTEM ;
        if( toupper(arg[i]) == 'A' )    *attrib |= ARCHIVE ;
        if( toupper(arg[i]) == 'H' )    *attrib |= HIDDEN ;
        }
    }

error(msg)
    char *msg;
    {
    fprintf(stderr,"Error: %s\n", msg);
    fprintf(stderr,"Usage: chmod [+-=][rhsa] file(s)");
    exit(1) ;
    }