BSD 3 release

[unix-history] / usr / src / cmd / chmod.c

/*
* chmod [ugoa][+-=][rwxstugo] files
*  change mode of files
*/
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>

#define USER    05700   /* user's bits */
#define GROUP   02070   /* group's bits */
#define OTHER   00007   /* other's bits */
#define ALL     01777   /* all (note absence of setuid, etc) */

#define READ    00444   /* read permit */
#define WRITE   00222   /* write permit */
#define EXEC    00111   /* exec permit */
#define SETID   06000   /* set[ug]id */
#define STICKY  01000   /* sticky bit */

char    *ms;
int     um;
struct  stat st;

main(argc,argv)
char **argv;
{
       register i;
       register char *p;
       int status = 0;

       if (argc < 3) {
               fprintf(stderr, "Usage: chmod [ugoa][+-=][rwxstugo] file ...\n");
               exit(255);
       }
       ms = argv[1];
       um = umask(0);
       newmode(0);
       for (i = 2; i < argc; i++) {
               p = argv[i];
               if (stat(p, &st) < 0) {
                       fprintf(stderr, "chmod: can't access %s\n", p);
                       ++status;
                       continue;
               }
               ms = argv[1];
               if (chmod(p, newmode(st.st_mode)) < 0) {
                       fprintf(stderr, "chmod: can't change %s\n", p);
                       ++status;
                       continue;
               }
       }
       exit(status);
}

newmode(nm)
unsigned nm;
{
       register o, m, b;

       m = abs();
       if (!*ms)
               return(m);
       do {
               m = who();
               while (o = what()) {
                       b = where(nm);
                       switch (o) {
                       case '+':
                               nm |= b & m;
                               break;
                       case '-':
                               nm &= ~(b & m);
                               break;
                       case '=':
                               nm &= ~m;
                               nm |= b & m;
                               break;
                       }
               }
       } while (*ms++ == ',');
       if (*--ms) {
               fprintf(stderr, "chmod: invalid mode\n");
               exit(255);
       }
       return(nm);
}

abs()
{
       register c, i;

       i = 0;
       while ((c = *ms++) >= '0' && c <= '7')
               i = (i << 3) + (c - '0');
       ms--;
       return(i);
}

who()
{
       register m;

       m = 0;
       for (;;) switch (*ms++) {
       case 'u':
               m |= USER;
               continue;
       case 'g':
               m |= GROUP;
               continue;
       case 'o':
               m |= OTHER;
               continue;
       case 'a':
               m |= ALL;
               continue;
       default:
               ms--;
               if (m == 0)
                       m = ALL & ~um;
               return m;
       }
}

what()
{
       switch (*ms) {
       case '+':
       case '-':
       case '=':
               return *ms++;
       }
       return(0);
}

where(om)
register om;
{
       register m;

       m = 0;
       switch (*ms) {
       case 'u':
               m = (om & USER) >> 6;
               goto dup;
       case 'g':
               m = (om & GROUP) >> 3;
               goto dup;
       case 'o':
               m = (om & OTHER);
       dup:
               m &= (READ|WRITE|EXEC);
               m |= (m << 3) | (m << 6);
               ++ms;
               return m;
       }
       for (;;) switch (*ms++) {
       case 'r':
               m |= READ;
               continue;
       case 'w':
               m |= WRITE;
               continue;
       case 'x':
               m |= EXEC;
               continue;
       case 's':
               m |= SETID;
               continue;
       case 't':
               m |= STICKY;
               continue;
       default:
               ms--;
               return m;
       }
}