chmode.c (was Re: chmod args)

[michael regoli]

In article <1771 at papaya.bbn.com> rsalz at bbn.com (Rich Salz) writes:
| [ Note the follow-ups.]
| 
| Why hasn't anyone written a chmod(1) that takes a bloody "rwsr-xr-x" string?
| 	/r$
| -- 
| Please send comp.sources.unix-related mail to rsalz at uunet.uu.net.

][

here's something i found lying around that does exactly that (well,
almost--but it's a start).

if an industrious soul wants to make improvements to allow more than
any combination of "rwxrwxrwx" (e.g., "rwsr-xr-x") the patches would
be most appreciated.

please post your patches here.  or rewrite the whole damn thing. 

--
michael regoli
regoli at iubacs.bitnet
regoli at sivler.bacs.indiana.edu
...rutgers!iuvax!silver!regoli
--
/*
 *
 *	CHMODE.C
 *
 *	New version of the chmod program: accepts inputs of the
 *	same format as given by the ls -l command, ie it can
 *	be invoked like 'chmode rwxrw-r-- *' to make the modes
 *	of each file specified match the template!
 *
 *	If automatic aggregate initialization is available, 
 *	compile with:
 *
 *		cc -Dauto chmode.c -o chmode
 *
 *	otherwise use:
 *
 *		cc chmode.c -o chmode
 *
 */

#include <whoami.h>
#include <stdio.h>

#define ERROR   -1

#define O_RD    256     /** 400 octal **/
#define O_WR    128     /** 200 octal **/
#define O_EX    64      /** 100 octal **/
#define G_RD    32      /**  40 octal **/
#define G_WR    16      /**  20 octal **/
#define G_EX    8       /**  10 octal **/
#define E_RD    4
#define E_WR    2
#define E_EX    1

main(argc, argv)
int argc;
char *argv[];
{
        register int newmode;
	register int j;
        char     buffer[16];

        if (argc < 3)
          exit(printf("Usage: %s <graphic mode> <file(s)>\n",argv[0]));

        --argc;
	newmode = 0;
	j = 1;

        strncpy(buffer,argv[j++], 9);

        if (strlen(buffer) != 9)
          exit(printf("Usage: %s <9 char graphic mode> <file(s)>\n",argv[0]));

        /** lets figure out the graphic mode translation! **/

        if ((newmode = translate(buffer)) == ERROR) {
          printf("Bad graphic mode designator!  Please use 'rwxrwxrwx' as a template, \n");
          printf("indicating those accesses that you desire to prevent with a dash\n");
          printf("      For example: 'chmode rw-r--r-- test.c'\n");
          exit(1);
        }

        while (--argc > 0)
          chmod(argv[j++], newmode);
}

int
translate(buffer)
char buffer[];
{
        /** translate a graphic representation of file access to
            an equivalent number as defined in CHMOD(2) **/

        register int loc = 0, sum = 0, val; 
#ifdef auto
        char type[] = "rwxrwxrwx"; 
        int mode[] = { O_RD, O_WR, O_EX, G_RD, G_WR, G_EX, E_RD, E_WR, E_EX };
#else
        char type[9]; 
        int mode[9];

        mode[0] = O_RD; mode[1] = O_WR; mode[2] = O_EX;
        mode[3] = G_RD; mode[4] = G_WR; mode[5] = G_EX;
        mode[6] = E_RD; mode[7] = E_WR; mode[8] = E_EX;

        strcpy(type,"rwxrwxrwx");
#endif

        for (loc = 0; loc < 9; loc++)
          if ((val = check(buffer[loc], type[loc], mode[loc])) == ERROR)
            return(ERROR);
          else sum += val;

        return(sum);
}

int
check(ch, type, mask)
char ch;
int mask;
{
        /** check to see if ch is either type or '-', returning
            either mask or ERROR **/

        if (ch == type) return(mask);
        else if (ch == '-') return(0);
        else return(ERROR);
}

/*
 *	CHMODE.C:  Finis.
 */