/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1989, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Tony Nardo of the Johns Hopkins University/Applied Physics Lab.
 *
 * 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.
 */

/*
 * Luke Mewburn <lm@rmit.edu.au> added the following on 940622:
 *    - mail status ("No Mail", "Mail read:...", or "New Mail ...,
 *      Unread since ...".)
 *    - 4 digit phone extensions (3210 is printed as x3210.)
 *    - host/office toggling in short format with -h & -o.
 *    - short day names (`Tue' printed instead of `Jun 21' if the
 *      login time is < 6 days.
 */

/*
 * Finger prints out information about users.  It is not portable since
 * certain fields (e.g. the full user name, office, and phone numbers) are
 * extracted from the gecos field of the passwd file which other UNIXes
 * may not have or may use for other things.
 *
 * There are currently two output formats; the short format is one line
 * per user and displays login name, tty, login time, real name, idle time,
 * and either remote host information (default) or office location/phone
 * number, depending on if -h or -o is used respectively.
 * The long format gives the same information (in a more legible format) as
 * well as home directory, shell, mail info, and .plan/.project files.
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <db.h>
#include <err.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <utmpx.h>
#include <locale.h>

#include "finger.h"
#include "pathnames.h"

DB *db;
time_t now;
static int kflag, mflag, sflag;
int entries, gflag, lflag, pplan, oflag;
sa_family_t family = PF_UNSPEC;
int d_first = -1;
char tbuf[1024];
int invoker_root = 0;

static void loginlist(void);
static int option(int, char **);
static void usage(void) __dead2;
static void userlist(int, char **);

static int
option(int argc, char **argv)
{
        int ch;

        optind = 1;             /* reset getopt */

        while ((ch = getopt(argc, argv, "46gklmpsho")) != -1)
                switch(ch) {
                case '4':
                        family = AF_INET;
                        break;
                case '6':
                        family = AF_INET6;
                        break;
                case 'g':
                        gflag = 1;
                        break;
                case 'k':
                        kflag = 1;              /* keep going without utmp */
                        break;
                case 'l':
                        lflag = 1;              /* long format */
                        break;
                case 'm':
                        mflag = 1;              /* force exact match of names */
                        break;
                case 'p':
                        pplan = 1;              /* don't show .plan/.project */
                        break;
                case 's':
                        sflag = 1;              /* short format */
                        break;
                case 'h':
                        oflag = 0;              /* remote host info */
                        break;
                case 'o':
                        oflag = 1;              /* office info */
                        break;
                case '?':
                default:
                        usage();
                }

        return optind;
}

static void
usage(void)
{
        (void)fprintf(stderr,
            "usage: finger [-46gklmpsho] [user ...] [user@host ...]\n");
        exit(1);
}

int
main(int argc, char **argv)
{
        int envargc, argcnt;
        char *envargv[3];
        struct passwd *pw;
        static char myname[] = "finger";

        if (getuid() == 0 || geteuid() == 0) {
                invoker_root = 1;
                if ((pw = getpwnam(UNPRIV_NAME)) && pw->pw_uid > 0) {
                        if (setgid(pw->pw_gid) != 0)
                                err(1, "setgid()");
                        if (setuid(pw->pw_uid) != 0)
                                err(1, "setuid()");
                } else {
                        if (setgid(UNPRIV_UGID) != 0)
                                err(1, "setgid()");
                        if (setuid(UNPRIV_UGID) != 0)
                                err(1, "setuid()");
                }
        }

        (void) setlocale(LC_ALL, "");

                                /* remove this line to get remote host */
        oflag = 1;              /* default to old "office" behavior */

        /*
         * Process environment variables followed by command line arguments.
         */
        if ((envargv[1] = getenv("FINGER"))) {
                envargc = 2;
                envargv[0] = myname;
                envargv[2] = NULL;
                (void) option(envargc, envargv);
        }

        argcnt = option(argc, argv);
        argc -= argcnt;
        argv += argcnt;

        (void)time(&now);
        setpassent(1);
        if (!*argv) {
                /*
                 * Assign explicit "small" format if no names given and -l
                 * not selected.  Force the -s BEFORE we get names so proper
                 * screening will be done.
                 */
                if (!lflag)
                        sflag = 1;      /* if -l not explicit, force -s */
                loginlist();
                if (entries == 0)
                        (void)printf("No one logged on.\n");
        } else {
                userlist(argc, argv);
                /*
                 * Assign explicit "large" format if names given and -s not
                 * explicitly stated.  Force the -l AFTER we get names so any
                 * remote finger attempts specified won't be mishandled.
                 */
                if (!sflag)
                        lflag = 1;      /* if -s not explicit, force -l */
        }
        if (entries) {
                if (lflag)
                        lflag_print();
                else
                        sflag_print();
        }
        return (0);
}

static void
loginlist(void)
{
        PERSON *pn;
        DBT data, key;
        struct passwd *pw;
        struct utmpx *user;
        int r, sflag1;

        if (kflag)
                errx(1, "can't list logins without reading utmp");

        setutxent();
        while ((user = getutxent()) != NULL) {
                if (user->ut_type != USER_PROCESS)
                        continue;
                if ((pn = find_person(user->ut_user)) == NULL) {
                        if ((pw = getpwnam(user->ut_user)) == NULL)
                                continue;
                        if (hide(pw))
                                continue;
                        pn = enter_person(pw);
                }
                enter_where(user, pn);
        }
        endutxent();
        if (db && lflag)
                for (sflag1 = R_FIRST;; sflag1 = R_NEXT) {
                        PERSON *tmp;

                        r = (*db->seq)(db, &key, &data, sflag1);
                        if (r == -1)
                                err(1, "db seq");
                        if (r == 1)
                                break;
                        memmove(&tmp, data.data, sizeof tmp);
                        enter_lastlog(tmp);
                }
}

static void
userlist(int argc, char **argv)
{
        PERSON *pn;
        DBT data, key;
        struct utmpx *user;
        struct passwd *pw;
        int r, sflag1, *used, *ip;
        char **ap, **nargv, **np, **p;
        FILE *conf_fp;
        char conf_alias[LINE_MAX];
        char *conf_realname;
        int conf_length;

        if ((nargv = malloc((argc+1) * sizeof(char *))) == NULL ||
            (used = calloc(argc, sizeof(int))) == NULL)
                err(1, NULL);

        /* Pull out all network requests. */
        for (ap = p = argv, np = nargv; *p; ++p)
                if (strchr(*p, '@'))
                        *np++ = *p;
                else
                        *ap++ = *p;

        *np++ = NULL;
        *ap++ = NULL;

        if (!*argv)
                goto net;

        /*
         * Mark any arguments beginning with '/' as invalid so that we
         * don't accidentally confuse them with expansions from finger.conf
         */
        for (p = argv, ip = used; *p; ++p, ++ip)
            if (**p == '/') {
                *ip = 1;
                warnx("%s: no such user", *p);
            }

        /*
         * Traverse the finger alias configuration file of the form
         * alias:(user|alias), ignoring comment lines beginning '#'.
         */
        if ((conf_fp = fopen(_PATH_FINGERCONF, "r")) != NULL) {
            while(fgets(conf_alias, sizeof(conf_alias), conf_fp) != NULL) {
                conf_length = strlen(conf_alias);
                if (*conf_alias == '#' || conf_alias[--conf_length] != '\n')
                    continue;
                conf_alias[conf_length] = '\0';      /* Remove trailing LF */
                if ((conf_realname = strchr(conf_alias, ':')) == NULL)
                    continue;
                *conf_realname = '\0';               /* Replace : with NUL */
                for (p = argv; *p; ++p) {
                    if (strcmp(*p, conf_alias) == 0) {
                        if ((*p = strdup(conf_realname+1)) == NULL) {
                            err(1, NULL);
                        }
                    }
                }
            }
            (void)fclose(conf_fp);
        }

        /*
         * Traverse the list of possible login names and check the login name
         * and real name against the name specified by the user. If the name
         * begins with a '/', try to read the file of that name instead of
         * gathering the traditional finger information.
         */
        if (mflag)
                for (p = argv, ip = used; *p; ++p, ++ip) {
                        if (**p != '/' || *ip == 1 || !show_text("", *p, "")) {
                                if (((pw = getpwnam(*p)) != NULL) && !hide(pw))
                                        enter_person(pw);
                                else if (!*ip)
                                        warnx("%s: no such user", *p);
                        }
                }
        else {
                while ((pw = getpwent()) != NULL) {
                        for (p = argv, ip = used; *p; ++p, ++ip)
                                if (**p == '/' && *ip != 1
                                    && show_text("", *p, ""))
                                        *ip = 1;
                                else if (match(pw, *p) && !hide(pw)) {
                                        enter_person(pw);
                                        *ip = 1;
                                }
                }
                for (p = argv, ip = used; *p; ++p, ++ip)
                        if (!*ip)
                                warnx("%s: no such user", *p);
        }

        /* Handle network requests. */
net:    for (p = nargv; *p;) {
                netfinger(*p++);
                if (*p || entries)
                    printf("\n");
        }

        free(nargv);
        free(used);
        if (entries == 0)
                return;

        if (kflag)
                return;

        /*
         * Scan thru the list of users currently logged in, saving
         * appropriate data whenever a match occurs.
         */
        setutxent();
        while ((user = getutxent()) != NULL) {
                if (user->ut_type != USER_PROCESS)
                        continue;
                if ((pn = find_person(user->ut_user)) == NULL)
                        continue;
                enter_where(user, pn);
        }
        endutxent();
        if (db)
                for (sflag1 = R_FIRST;; sflag1 = R_NEXT) {
                        PERSON *tmp;

                        r = (*db->seq)(db, &key, &data, sflag1);
                        if (r == -1)
                                err(1, "db seq");
                        if (r == 1)
                                break;
                        memmove(&tmp, data.data, sizeof tmp);
                        enter_lastlog(tmp);
                }
}