BSD 1 development

[unix-history] / s1 / who.c

/*
* who
*/

int     fout;
int     buf[256];
char pbuf[100];

main(argc, argv)
char **argv;
{
       char *s, *cbuf;
       int n, fi, i;
       int tty;
       struct {
               char name[8];
               char tty;
               char changed;
               int time[2];
               int uid;
       } *p;

       s = "/etc/utmp";
       if(argc == 2)
               s = argv[1];
       fi = open(s, 0);
       if(fi < 0) {
               write("cannot open wtmp\n", 17);
               exit();
       }
       fout = dup(1);
       close(1);
       if (argc==3)
               tty = ttyn(2);

loop:
       n = read(fi, buf, 512);
       if(n == 0) {
               flush();
               if (argc==3)
                       write(fout, "Nobody.\n", 8);
               exit();
       }

       p = &buf;
       for(p = &buf; (n =- 16)>=0; p++) {
               if (argc==3 && tty!=p->tty)
                       continue;
               if(p->name[0] == '\0' && argc==1)
                       continue;
               for(i=0; i<8; i++) {
                       if (p->name[i]<' ' || p->name[i]>'z')
                               p->name[i] = ' ';
                       putchar(p->name[i]);
               }
               putchar(' ');
               for(i=0; i<3; i++)
                       putchar("tty"[i]);
               i = p->tty;
               if (i < 033) {
                       putchar('^');
                       putchar(i - 1 + 'a');
               } else {
                       putchar(i);
                       putchar(' ');
               }
               cbuf = ctime(p->time);
               for(i=3; i<16; i++)
                       putchar(cbuf[i]);
               if (p->changed && argc != 2)
               {
                       if (getpw(p->uid, pbuf))
                               goto out;
                       s = pbuf;
                       putchar(' ');
                       for(i=0; i < 8; i++)
                               if (*s == ':')
                                       break;
                               else    putchar(*s++);
               }
out:
               putchar('\n');
               if (argc==3) {
                       flush();
                       exit();
               }
       }
       goto loop;
}