/*      $NetBSD: who.c,v 1.25 2015/11/21 15:01:43 christos Exp $        */

/*
 * 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. 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.
 */

#include <sys/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1989, 1993\
 The Regents of the University of California.  All rights reserved.");
#endif /* not lint */

#ifndef lint
#if 0
static char sccsid[] = "@(#)who.c       8.1 (Berkeley) 6/6/93";
#endif
__RCSID("$NetBSD: who.c,v 1.25 2015/11/21 15:01:43 christos Exp $");
#endif /* not lint */

#include <sys/types.h>
#include <sys/stat.h>

#include <err.h>
#include <locale.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#ifdef SUPPORT_UTMP
#include <utmp.h>
#endif
#ifdef SUPPORT_UTMPX
#include <utmpx.h>
#endif

#include "utmpentry.h"

static void output_labels(void);
static void who_am_i(const char *, int);
static void usage(void) __dead;
static void process(const char *, int);
static void eprint(const struct utmpentry *);
static void print(const char *, const char *, time_t, const char *, pid_t pid,
    uint16_t term, uint16_t xit, uint16_t sess, uint16_t type);
static void quick(const char *);

static int show_term;                   /* show term state */
static int show_idle;                   /* show idle time */
static int show_details;                /* show exit status etc. */

struct ut_type_names {
  int type;
  const char *name;
} ut_type_names[] = {
#ifdef SUPPORT_UTMPX
  { EMPTY, "empty" }, 
  { RUN_LVL, "run level" }, 
  { BOOT_TIME, "boot time" }, 
  { OLD_TIME, "old time" }, 
  { NEW_TIME, "new time" }, 
  { INIT_PROCESS, "init process" }, 
  { LOGIN_PROCESS, "login process" }, 
  { USER_PROCESS, "user process" }, 
  { DEAD_PROCESS, "dead process" }, 
#if defined(_NETBSD_SOURCE)
  { ACCOUNTING, "accounting" }, 
  { SIGNATURE, "signature" },
  { DOWN_TIME, "down time" },
#endif /* _NETBSD_SOURCE */
#endif /* SUPPORT_UTMPX */
  { -1, "unknown" }
};

int
main(int argc, char *argv[])
{
        int c, only_current_term, show_labels, quick_mode, default_mode;
        int et = 0;

        setlocale(LC_ALL, "");

        only_current_term = show_term = show_idle = show_labels = 0;
        quick_mode = default_mode = 0;

        while ((c = getopt(argc, argv, "abdHlmpqrsTtuv")) != -1) {
                switch (c) {
                case 'a':
                        et = -1;
                        show_idle = show_details = 1;
                        break;
                case 'b':
                        et |= (1 << BOOT_TIME);
                        break;
                case 'd':
                        et |= (1 << DEAD_PROCESS);
                        break;
                case 'H':
                        show_labels = 1;
                        break;
                case 'l':
                        et |= (1 << LOGIN_PROCESS);
                        break;
                case 'm':
                        only_current_term = 1;
                        break;
                case 'p':
                        et |= (1 << INIT_PROCESS);
                        break;
                case 'q':
                        quick_mode = 1;
                        break;
                case 'r':
                        et |= (1 << RUN_LVL);
                        break;
                case 's':
                        default_mode = 1;
                        break;
                case 'T':
                        show_term = 1;
                        break;
                case 't':
                        et |= (1 << NEW_TIME);
                        break;
                case 'u':
                        show_idle = 1;
                        break;
                case 'v':
                        show_details = 1;
                        break;
                default:
                        usage();
                        /* NOTREACHED */
                }
        }
        argc -= optind;
        argv += optind;

        if (et != 0)
                etype = et;

        if (chdir("/dev")) {
                err(EXIT_FAILURE, "cannot change directory to /dev");
                /* NOTREACHED */
        }

        if (default_mode)
                only_current_term = show_term = show_idle = 0;

        switch (argc) {
        case 0:                                 /* who */
                if (quick_mode) {
                        quick(NULL);
                } else if (only_current_term) {
                        who_am_i(NULL, show_labels);
                } else {
                        process(NULL, show_labels);
                }
                break;
        case 1:                                 /* who utmp_file */
                if (quick_mode) {
                        quick(*argv);
                } else if (only_current_term) {
                        who_am_i(*argv, show_labels);
                } else {
                        process(*argv, show_labels);
                }
                break;
        case 2:                                 /* who am i */
                who_am_i(NULL, show_labels);
                break;
        default:
                usage();
                /* NOTREACHED */
        }

        return 0;
}

static char *
strrstr(const char *str, const char *pat)
{
        const char *estr;
        size_t len;
        if (*pat == '\0')
                return __UNCONST(str);

        len = strlen(pat);

        for (estr = str + strlen(str); str < estr; estr--)
                if (strncmp(estr, pat, len) == 0)
                        return __UNCONST(estr);
        return NULL;
}

static void
who_am_i(const char *fname, int show_labels)
{
        struct passwd *pw;
        const char *p;
        char *t;
        time_t now;
        struct utmpentry *ehead, *ep;

        /* search through the utmp and find an entry for this tty */
        if ((p = ttyname(STDIN_FILENO)) != NULL) {

                /* strip directory prefixes for ttys */
                if ((t = strrstr(p, "/pts/")) != NULL ||
                    (t = strrchr(p, '/')) != NULL)
                        p = t + 1;

                (void)getutentries(fname, &ehead);
                for (ep = ehead; ep; ep = ep->next)
                        if (strcmp(ep->line, p) == 0) {
                                if (show_labels)
                                        output_labels();
                                eprint(ep);
                                return;
                        }
        } else
                p = "tty??";

        (void)time(&now);
        pw = getpwuid(getuid());
        if (show_labels)
                output_labels();
        print(pw ? pw->pw_name : "?", p, now, "", getpid(), 0, 0, 0, 0);
}

static void
process(const char *fname, int show_labels)
{
        struct utmpentry *ehead, *ep;
        (void)getutentries(fname, &ehead);
        if (show_labels)
                output_labels();
        for (ep = ehead; ep != NULL; ep = ep->next)
                eprint(ep);
}

static void
eprint(const struct utmpentry *ep)
{
        print(ep->name, ep->line, (time_t)ep->tv.tv_sec, ep->host, ep->pid,
            ep->term, ep->exit, ep->sess, ep->type);
}

static void
print(const char *name, const char *line, time_t t, const char *host,
    pid_t pid, uint16_t term, uint16_t xit, uint16_t sess, uint16_t type)
{
        struct stat sb;
        char state;
        static time_t now = 0;
        time_t idle;
        const char *types = NULL;
        size_t i;
        char *tstr;

        state = '?';
        idle = 0;

        for (i = 0; ut_type_names[i].type >= 0; i++) {
                types = ut_type_names[i].name;
                if (ut_type_names[i].type == type)
                        break;
        }
        
        if (show_term || show_idle) {
                if (now == 0)
                        time(&now);
                
                if (stat(line, &sb) == 0) {
                        state = (sb.st_mode & 020) ? '+' : '-';
                        idle = now - sb.st_atime;
                }
                
        }

        (void)printf("%-*.*s ", (int)maxname, (int)maxname, name);

        if (show_term)
                (void)printf("%c ", state);

        (void)printf("%-*.*s ", (int)maxline, (int)maxline, line);
        tstr = ctime(&t);
        (void)printf("%.12s ", tstr ? tstr + 4 : "?");

        if (show_idle) {
                if (idle < 60) 
                        (void)printf("  .   ");
                else if (idle < (24 * 60 * 60))
                        (void)printf("%02ld:%02ld ", 
                                     (long)(idle / (60 * 60)),
                                     (long)(idle % (60 * 60)) / 60);
                else
                        (void)printf(" old  ");

                (void)printf("\t%6d", pid);
                
                if (show_details) {
                        if (type == RUN_LVL)
                                (void)printf("\tnew=%c old=%c", term, xit);
                        else
                                (void)printf("\tterm=%d exit=%d", term, xit);
                        (void)printf(" sess=%d", sess);
                        (void)printf(" type=%s ", types);
                }
        }
        
        if (*host)
                (void)printf("\t(%.*s)", (int)maxhost, host);
        (void)putchar('\n');
}

static void
output_labels(void)
{
        (void)printf("%-*.*s ", (int)maxname, (int)maxname, "USER");

        if (show_term)
                (void)printf("S ");
        
        (void)printf("%-*.*s ", (int)maxline, (int)maxline, "LINE");
        (void)printf("WHEN         ");

        if (show_idle) {
                (void)printf("IDLE  ");
                (void)printf("\t   PID");
        
                (void)printf("\tCOMMENT");
        }               

        (void)putchar('\n');
}

static void
quick(const char *fname)
{
        struct utmpentry *ehead, *ep;
        int num = 0;

        (void)getutentries(fname, &ehead);
        for (ep = ehead; ep != NULL; ep = ep->next) {
                (void)printf("%-*s ", (int)maxname, ep->name);
                if ((++num % 8) == 0)
                        (void)putchar('\n');
        }
        if (num % 8)
                (void)putchar('\n');

        (void)printf("# users = %d\n", num);
}

static void
usage(void)
{
        (void)fprintf(stderr, "Usage: %s [-abdHlmqrsTtuv] [file]\n\t%s am i\n",
            getprogname(), getprogname());
        exit(EXIT_FAILURE);
}