gno/usr.bin/who/who.c

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/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Michael Fischbein.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef lint
static char copyright[] =
"@(#) Copyright (c) 1989, 1993\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
static char sccsid[] = "@(#)who.c 8.1 (Berkeley) 6/6/93";
#endif /* not lint */
#include <sys/types.h>
#include <sys/file.h>
#include <time.h>
#include <pwd.h>
#include <utmp.h>
#include <stdio.h>
#ifdef __GNO__
#include <sys/errno.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#endif
static void output(struct utmp *up);
static FILE *file(char *name);
int
main(int argc, char **argv)
{
register char *p;
static struct utmp usr;
struct passwd *pw;
#ifdef __GNO__
FILE *ufp;
char *t;
#else
FILE *ufp, *file();
char *t, *rindex(), *strcpy(), *strncpy(), *ttyname();
#endif
switch (argc) {
case 1: /* who */
ufp = file(_PATH_UTMP);
/* only entries with both name and line fields */
while (fread((char *)&usr, sizeof(usr), 1, ufp) == 1)
if (*usr.ut_name && *usr.ut_line)
output(&usr);
break;
case 2: /* who utmp_file */
ufp = file(argv[1]);
/* all entries */
while (fread((char *)&usr, sizeof(usr), 1, ufp) == 1)
output(&usr);
break;
case 3: /* who am i */
ufp = file(_PATH_UTMP);
/* search through the utmp and find an entry for this tty */
if (p = ttyname(0)) {
/* strip any directory component */
if (t = rindex(p, '/'))
p = t + 1;
while (fread((char *)&usr, sizeof(usr), 1, ufp) == 1)
if (*usr.ut_name && !strcmp(usr.ut_line, p)) {
output(&usr);
exit(0);
}
/* well, at least we know what the tty is */
(void)strncpy(usr.ut_line, p, UT_LINESIZE);
} else
(void)strcpy(usr.ut_line, "tty??");
pw = getpwuid(getuid());
(void)strncpy(usr.ut_name, pw ? pw->pw_name : "?", UT_NAMESIZE);
(void)time(&usr.ut_time);
*usr.ut_host = '\0';
output(&usr);
break;
default:
(void)fprintf(stderr, "usage: who [ file ]\n who am i\n");
exit(1);
}
exit(0);
}
static void
output(struct utmp *up)
{
static char buf[80];
(void)printf("%-*.*s %-*.*s", UT_NAMESIZE, UT_NAMESIZE, up->ut_name,
UT_LINESIZE, UT_LINESIZE, up->ut_line);
#ifdef __GNO__
sprintf(buf, "%s", asctime(localtime(&up->ut_time)));
#else
(void)strftime(buf, sizeof(buf), "%c", localtime(&up->ut_time));
#endif
(void)printf("%.12s", buf + 4);
if (*up->ut_host)
printf("\t(%.*s)", UT_HOSTSIZE, up->ut_host);
(void)putchar('\n');
}
static FILE *
file(char *name)
{
extern int errno;
FILE *ufp;
#ifndef __GNO__
char *strerror();
#endif
if (!(ufp = fopen(name, "r"))) {
(void)fprintf(stderr, "who: %s: %s.\n", name, strerror(errno));
exit(1);
}
return(ufp);
}