cleanups

[unix-history] / usr / src / usr.bin / who / who.c

/*
* Copyright (c) 1980 Regents of the University of California.
* All rights reserved.  The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*/

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1980 Regents of the University of California.\n\
All rights reserved.\n";
#endif not lint

#ifndef lint
static char sccsid[] = "@(#)who.c       5.2 (Berkeley) %G%";
#endif not lint

/*
* who
*/

#include <sys/param.h>
#include <utmp.h>
#include <pwd.h>
#include <stdio.h>
#include <strings.h>
#include <ctype.h>

#define NMAX    sizeof(utmp.ut_name)
#define LMAX    sizeof(utmp.ut_line)
#define HMAX    sizeof(utmp.ut_host)

static struct utmp      utmp;           /* read buffer */

main(argc,argv)
int     argc;
char    **argv;
{
       register FILE   *fp;                    /* utmp file pointer */
       register char   *tp,                    /* tty name */
                       *fname;                 /* utmp file name */
       struct passwd   *pw,                    /* user passwd structure */
                       *getpwuid();
       char    hostname[MAXHOSTNAMELEN],       /* host name */
               *ttyname();
       uid_t   getuid();
       long    time();

       switch(argc) {
               case 2:
                       fname = argv[1];
                       break;
               case 3:
                       if (!(tp = ttyname(0))) {
                               /*
                                * no tty -- use best guess from passwd file.
                                * next line is a kludge, but as of now getuid
                                * returns a "uid_t" and getpwuid takes an int.
                                */
                               pw = getpwuid((int)getuid());
                               strncpy(utmp.ut_name,pw ? pw->pw_name : "?",NMAX);
                               strcpy(utmp.ut_line,"tty??");
                               time(&utmp.ut_time);
                               putline();
                               exit(0);
                       }
                       tp = rindex(tp,'/') + 1;
                       if (gethostname(hostname,sizeof(hostname)) == -1) {
                               perror("gethostname");
                               exit(1);
                       }
               case 1:
                       fname = "/etc/utmp";
                       break;
               default:
                       fputs("usage: who [ utmp_file ]\nor who am i\n",stderr);
                       exit(1);
       }
       if (!(fp = fopen(fname,"r"))) {
               perror(fname);
               exit(1);
       }
       while (fread((char *)&utmp,sizeof(utmp),1,fp) == 1)
               if (argc == 3) {
                       if (!strcmp(utmp.ut_line,tp)) {
                               printf("%s!",hostname);
                               putline();
                               exit(0);
                       }
               }
               else if (argc != 1 || *utmp.ut_name)
                       putline();
}

putline()
{
       register char   *cbuf;
       char    *ctime();

       cbuf = ctime(&utmp.ut_time) + 4;
       printf("%-*.*s %-*.*s%.12s",NMAX,NMAX,utmp.ut_name,LMAX,LMAX,utmp.ut_line,cbuf);
       if (*utmp.ut_host)
               printf("\t(%.*s)",HMAX,utmp.ut_host);
       putchar('\n');
}