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who.c revision 1.1.1.3 
      1 /*
      2  * Copyright (c) 1989, 1993
      3  *	The Regents of the University of California.  All rights reserved.
      4  *
      5  * This code is derived from software contributed to Berkeley by
      6  * Michael Fischbein.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  * 3. All advertising materials mentioning features or use of this software
     17  *    must display the following acknowledgement:
     18  *	This product includes software developed by the University of
     19  *	California, Berkeley and its contributors.
     20  * 4. Neither the name of the University nor the names of its contributors
     21  *    may be used to endorse or promote products derived from this software
     22  *    without specific prior written permission.
     23  *
     24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     34  * SUCH DAMAGE.
     35  */
     36 
     37 #ifndef lint
     38 static char copyright[] =
     39 "@(#) Copyright (c) 1989, 1993\n\
     40 	The Regents of the University of California.  All rights reserved.\n";
     41 #endif /* not lint */
     42 
     43 #ifndef lint
     44 static char sccsid[] = "@(#)who.c	8.1 (Berkeley) 6/6/93";
     45 #endif /* not lint */
     46 
     47 #include <sys/types.h>
     48 #include <sys/file.h>
     49 #include <sys/time.h>
     50 #include <pwd.h>
     51 #include <utmp.h>
     52 #include <stdio.h>
     53 
     54 main(argc, argv)
     55 	int argc;
     56 	char **argv;
     57 {
     58 	register char *p;
     59 	struct utmp usr;
     60 	struct passwd *pw;
     61 	FILE *ufp, *file();
     62 	char *t, *rindex(), *strcpy(), *strncpy(), *ttyname();
     63 	time_t time();
     64 
     65 	switch (argc) {
     66 	case 1:					/* who */
     67 		ufp = file(_PATH_UTMP);
     68 		/* only entries with both name and line fields */
     69 		while (fread((char *)&usr, sizeof(usr), 1, ufp) == 1)
     70 			if (*usr.ut_name && *usr.ut_line)
     71 				output(&usr);
     72 		break;
     73 	case 2:					/* who utmp_file */
     74 		ufp = file(argv[1]);
     75 		/* all entries */
     76 		while (fread((char *)&usr, sizeof(usr), 1, ufp) == 1)
     77 			output(&usr);
     78 		break;
     79 	case 3:					/* who am i */
     80 		ufp = file(_PATH_UTMP);
     81 
     82 		/* search through the utmp and find an entry for this tty */
     83 		if (p = ttyname(0)) {
     84 			/* strip any directory component */
     85 			if (t = rindex(p, '/'))
     86 				p = t + 1;
     87 			while (fread((char *)&usr, sizeof(usr), 1, ufp) == 1)
     88 				if (usr.ut_name && !strcmp(usr.ut_line, p)) {
     89 					output(&usr);
     90 					exit(0);
     91 				}
     92 			/* well, at least we know what the tty is */
     93 			(void)strncpy(usr.ut_line, p, UT_LINESIZE);
     94 		} else
     95 			(void)strcpy(usr.ut_line, "tty??");
     96 		pw = getpwuid(getuid());
     97 		(void)strncpy(usr.ut_name, pw ? pw->pw_name : "?", UT_NAMESIZE);
     98 		(void)time(&usr.ut_time);
     99 		*usr.ut_host = '\0';
    100 		output(&usr);
    101 		break;
    102 	default:
    103 		(void)fprintf(stderr, "usage: who [ file ]\n       who am i\n");
    104 		exit(1);
    105 	}
    106 	exit(0);
    107 }
    108 
    109 output(up)
    110 	struct utmp *up;
    111 {
    112 	char *ctime();
    113 
    114 	(void)printf("%-*.*s %-*.*s", UT_NAMESIZE, UT_NAMESIZE, up->ut_name,
    115 	    UT_LINESIZE, UT_LINESIZE, up->ut_line);
    116 	(void)printf("%.12s", ctime(&up->ut_time) + 4);
    117 	if (*up->ut_host)
    118 		printf("\t(%.*s)", UT_HOSTSIZE, up->ut_host);
    119 	(void)putchar('\n');
    120 }
    121 
    122 FILE *
    123 file(name)
    124 	char *name;
    125 {
    126 	extern int errno;
    127 	FILE *ufp;
    128 	char *strerror();
    129 
    130 	if (!(ufp = fopen(name, "r"))) {
    131 		(void)fprintf(stderr, "who: %s: %s.\n", name, strerror(errno));
    132 		exit(1);
    133 	}
    134 	return(ufp);
    135 }
    136