BSD 4_3_Tahoe release

[unix-history] / usr / src / ucb / users.c

/*
* Copyright (c) 1980, 1987 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the University of California, Berkeley.  The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1980, 1987 Regents of the University of California.\n\
All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)users.c     5.6 (Berkeley) 6/29/88";
#endif /* not lint */

/*
* users
*/
#include <sys/types.h>
#include <utmp.h>
#include <stdio.h>

#define NMAX            sizeof(utmp.ut_name)
#define MAXUSERS        200
#define UTMP_FILE       "/etc/utmp"

static struct utmp utmp;                /* read structure */
static int ncnt;                        /* count of names */
static char *names[MAXUSERS];           /* names table */

main()
{
       register FILE *fp;              /* file pointer */

       if (!(fp = fopen(UTMP_FILE, "r"))) {
               perror(UTMP_FILE);
               exit(1);
       }
       while (fread((char *)&utmp, sizeof(utmp), 1, fp) == 1)
               if (*utmp.ut_name) {
                       if (++ncnt > MAXUSERS) {
                               ncnt = MAXUSERS;
                               fputs("users: too many users.\n", stderr);
                               break;
                       }
                       nsave();
               }
       summary();
       exit(0);
}

nsave()
{
       static char **namp = names;     /* pointer to names table */
       char *calloc();

       if (!(*namp = calloc((u_int)(NMAX + 1), sizeof(char)))) {
               fputs("users: malloc error.\n", stderr);
               exit(1);
       }
       bcopy(utmp.ut_name, *namp++, NMAX);
}

summary()
{
       register char **p;
       int scmp();

       if (!ncnt)
               return;
       qsort((char *)names, ncnt, sizeof(names[0]), scmp);
       fputs(names[0], stdout);
       for (p = &names[1]; --ncnt; ++p) {
               putchar(' ');
               fputs(*p, stdout);
       }
       putchar('\n');
}

scmp(p, q)
       char **p, **q;
{
       return(strcmp(*p, *q));
}