/*      @(#)last.c      8.2 (Berkeley) 4/2/94 */
/*      $NetBSD: last.c,v 1.15 2000/06/30 06:19:58 simonb Exp $ */

/*
 * Copyright (c) 1987, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 *
 * 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/param.h>
#include <sys/stat.h>

#include <err.h>
#include <fcntl.h>
#include <paths.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <tzfile.h>
#include <unistd.h>
#include <utmpx.h>

#ifndef UT_NAMESIZE
#define UT_NAMESIZE 8
#define UT_LINESIZE 8
#define UT_HOSTSIZE 16
#endif
#ifndef SIGNATURE
#define SIGNATURE -1
#endif



#define NO      0                       /* false/no */
#define YES     1                       /* true/yes */

#define TBUFLEN 30                      /* length of time string buffer */
#define TFMT    "%a %b %d %R"           /* strftime format string */
#define LTFMT   "%a %b %d %Y %T"        /* strftime long format string */
#define TFMTS   "%R"                    /* strftime format string - time only */
#define LTFMTS  "%T"                    /* strftime long format string - " */

/* fmttime() flags */
#define FULLTIME        0x1             /* show year, seconds */
#define TIMEONLY        0x2             /* show time only, not date */
#define GMT             0x4             /* show time at GMT, for offsets only */

#define MAXUTMP         1024;

typedef struct arg {
        char    *name;                  /* argument */
#define HOST_TYPE       -2
#define TTY_TYPE        -3
#define USER_TYPE       -4
        int     type;                   /* type of arg */
        struct arg      *next;          /* linked list pointer */
} ARG;
static ARG      *arglist;               /* head of linked list */

typedef struct ttytab {
        time_t  logout;                 /* log out time */
        char    tty[128];               /* terminal name */
        struct ttytab   *next;          /* linked list pointer */
} TTY;
static TTY      *ttylist;               /* head of linked list */

static struct utmpx *bufx;
static time_t   currentout;             /* current logout value */
static long     maxrec;                 /* records to display */
static int      fulltime = 0;           /* Display seconds? */

static void      addarg(int, char *);
static TTY      *addtty(const char *);
static void      hostconv(char *);
static char     *ttyconv(char *);
static void      wtmpx(const char *, int, int, int);
static char     *fmttime(time_t, int);
static void      usage(void);
static void      onintrx(int);
static int       wantx(struct utmpx *, int);

static
void usage(void)
{
        fprintf(stderr, "Usage: %s [-#%s] [-T] [-f file]"
            " [-h host] [-H hostsize] [-L linesize]\n"
            "\t    [-N namesize] [-t tty] [user ...]\n", getprogname(),
#if 0 /* XXX NOTYET_SUPPORT_UTMPX??? */
            "w"
#else
            ""
#endif
        );
        exit(1);
}

int
main(int argc, char *argv[])
{
        int ch;
        char *p;
        const char *file = NULL;
        int namesize = UT_NAMESIZE;
        int linesize = UT_LINESIZE;
        int hostsize = UT_HOSTSIZE;

        maxrec = -1;

        while ((ch = getopt(argc, argv, "0123456789f:h:H:L:N:t:T")) != -1)
                switch (ch) {
                case '0': case '1': case '2': case '3': case '4':
                case '5': case '6': case '7': case '8': case '9':
                        /*
                         * kludge: last was originally designed to take
                         * a number after a dash.
                         */
                        if (maxrec == -1) {
                                p = argv[optind - 1];
                                if (p[0] == '-' && p[1] == ch && !p[2])
                                        maxrec = atol(++p);
                                else
                                        maxrec = atol(argv[optind] + 1);
                                if (!maxrec)
                                        exit(0);
                        }
                        break;
                case 'f':
                        file = optarg;
                        break;
                case 'h':
                        hostconv(optarg);
                        addarg(HOST_TYPE, optarg);
                        break;
                case 't':
                        addarg(TTY_TYPE, ttyconv(optarg));
                        break;
                case 'U':
                        namesize = atoi(optarg);
                        break;
                case 'L':
                        linesize = atoi(optarg);
                        break;
                case 'H':
                        hostsize = atoi(optarg);
                        break;
                case 'T':
                        fulltime = 1;
                        break;
                case '?':
                default:
                        usage();
                }

        if (argc) {
                setlinebuf(stdout);
                for (argv += optind; *argv; ++argv) {
#define COMPATIBILITY
#ifdef  COMPATIBILITY
                        /* code to allow "last p5" to work */
                        addarg(TTY_TYPE, ttyconv(*argv));
#endif
                        addarg(USER_TYPE, *argv);
                }
        }
        if (file == NULL) {
                if (access(_PATH_WTMPX, R_OK) == 0)
                        file = _PATH_WTMPX;
                if (file == NULL)
                        errx(1, "Cannot access `%s'", _PATH_WTMPX);
        }
        wtmpx(file, namesize, linesize, hostsize);
        exit(0);
}


/*
 * addarg --
 *      add an entry to a linked list of arguments
 */
static void
addarg(int type, char *arg)
{
        ARG *cur;

        if (!(cur = (ARG *)malloc((u_int)sizeof(ARG))))
                err(1, "malloc failure");
        cur->next = arglist;
        cur->type = type;
        cur->name = arg;
        arglist = cur;
}

/*
 * addtty --
 *      add an entry to a linked list of ttys
 */
static TTY *
addtty(const char *tty)
{
        TTY *cur;

        if (!(cur = (TTY *)malloc((u_int)sizeof(TTY))))
                err(1, "malloc failure");
        cur->next = ttylist;
        cur->logout = currentout;
        memmove(cur->tty, tty, sizeof(cur->tty));
        return (ttylist = cur);
}

/*
 * hostconv --
 *      convert the hostname to search pattern; if the supplied host name
 *      has a domain attached that is the same as the current domain, rip
 *      off the domain suffix since that's what login(1) does.
 */
static void
hostconv(char *arg)
{
        static int first = 1;
        static char *hostdot, name[MAXHOSTNAMELEN + 1];
        char *argdot;

        if (!(argdot = strchr(arg, '.')))
                return;
        if (first) {
                first = 0;
                if (gethostname(name, sizeof(name)))
                        err(1, "gethostname");
                name[sizeof(name) - 1] = '\0';
                hostdot = strchr(name, '.');
        }
        if (hostdot && !strcasecmp(hostdot, argdot))
                *argdot = '\0';
}

/*
 * ttyconv --
 *      convert tty to correct name.
 */
static char *
ttyconv(char *arg)
{
        char *mval;

        /*
         * kludge -- we assume that all tty's end with
         * a two character suffix.
         */
        if (strlen(arg) == 2) {
                /* either 6 for "ttyxx" or 8 for "console" */
                if (!(mval = malloc((u_int)8)))
                        err(1, "malloc failure");
                if (!strcmp(arg, "co"))
                        strcpy(mval, "console");
                else {
                        strcpy(mval, "tty");
                        strcpy(mval + 3, arg);
                }
                return (mval);
        }
        if (!strncmp(arg, _PATH_DEV, sizeof(_PATH_DEV) - 1))
                return (arg + 5);
        return (arg);
}

/*
 * fmttime --
 *      return pointer to (static) formatted time string.
 */
static char *
fmttime(time_t t, int flags)
{
        struct tm *tm;
        static char tbuf[TBUFLEN];

        tm = (flags & GMT) ? gmtime(&t) : localtime(&t);
        if (tm == NULL) {
                strcpy(tbuf, "????");
                return tbuf;
        }
        strftime(tbuf, sizeof(tbuf),
            (flags & TIMEONLY)
             ? (flags & FULLTIME ? LTFMTS : TFMTS)
             : (flags & FULLTIME ? LTFMT : TFMT),
            tm);
        return (tbuf);
}

/*
 * wtmpx --
 *      read through the wtmpx file
 */
static void
wtmpx(const char *file, int namesz, int linesz, int hostsz)
{
        struct utmpx    *bp;            /* current structure */
        TTY     *T;                     /* tty list entry */
        struct stat     stb;            /* stat of file for sz */
        time_t  delta;                  /* time difference */
        off_t   bl;
        int     bytes, wfd;
        char    *ct;
        const char *crmsg;
        size_t  len = sizeof(*bufx) * MAXUTMP;

        if ((bufx = malloc(len)) == NULL)
                err(1, "Cannot allocate utmpx buffer");

        crmsg = NULL;

        if ((wfd = open(file, O_RDONLY, 0)) < 0 || fstat(wfd, &stb) == -1)
                err(1, "%s", file);
        bl = (stb.st_size + len - 1) / len;

        bufx[1].ut_xtime = time(NULL);
        (void)signal(SIGINT, onintrx);
        (void)signal(SIGQUIT, onintrx);

        while (--bl >= 0) {
                if (lseek(wfd, bl * len, SEEK_SET) == -1 ||
                    (bytes = read(wfd, bufx, len)) == -1)
                        err(1, "%s", file);
                for (bp = &bufx[bytes / sizeof(*bufx) - 1]; bp >= bufx; --bp) {
                        /*
                         * if the terminal line is '~', the machine stopped.
                         * see utmpx(5) for more info.
                         */
                        if (bp->ut_line[0] == '~' && !bp->ut_line[1]) {
                                /* everybody just logged out */
                                for (T = ttylist; T; T = T->next)
                                        T->logout = -bp->ut_xtime;
                                currentout = -bp->ut_xtime;
#ifdef __DragonFly__    /* XXX swildner: this should not be needed afaict */
                                if (!strncmp(bp->ut_name, "shutdown", namesz))
                                        crmsg = "shutdown";
                                else if (!strncmp(bp->ut_name, "reboot", namesz))
                                        crmsg = "reboot";
                                else
                                        crmsg = "crash";
#else
                                crmsg = strncmp(bp->ut_name, "shutdown",
                                    namesz) ? "crash" : "shutdown";
#endif
                                if (wantx(bp, NO)) {
                                        ct = fmttime(bp->ut_xtime, fulltime);
                                        printf("%-*.*s  %-*.*s %-*.*s %s\n",
                                            namesz, namesz, bp->ut_name,
                                            linesz, linesz, bp->ut_line,
                                            hostsz, hostsz, bp->ut_host, ct);
                                        if (maxrec != -1 && !--maxrec)
                                                return;
                                }
                                continue;
                        }
                        /*
                         * if the line is '{' or '|', date got set; see
                         * utmpx(5) for more info.
                         */
                        if ((bp->ut_line[0] == '{' || bp->ut_line[0] == '|')
                            && !bp->ut_line[1]) {
                                if (wantx(bp, NO)) {
                                        ct = fmttime(bp->ut_xtime, fulltime);
                                printf("%-*.*s  %-*.*s %-*.*s %s\n",
                                    namesz, namesz,
                                    bp->ut_name,
                                    linesz, linesz,
                                    bp->ut_line,
                                    hostsz, hostsz,
                                    bp->ut_host,
                                    ct);
                                        if (maxrec && !--maxrec)
                                                return;
                                }
                                continue;
                        }
                        /* find associated tty */
                        for (T = ttylist;; T = T->next) {
                                if (!T) {
                                        /* add new one */
                                        T = addtty(bp->ut_line);
                                        break;
                                }
                                if (!strncmp(T->tty, bp->ut_line, UTX_LINESIZE))
                                        break;
                        }
                        if (bp->ut_type == SIGNATURE)
                                continue;
                        if (bp->ut_name[0] && wantx(bp, YES)) {
                                ct = fmttime(bp->ut_xtime, fulltime);
                                printf("%-*.*s  %-*.*s %-*.*s %s ",
                                    namesz, namesz, bp->ut_name,
                                    linesz, linesz, bp->ut_line,
                                    hostsz, hostsz, bp->ut_host,
                                    ct);
                                if (!T->logout)
                                        puts("  still logged in");
                                else {
                                        if (T->logout < 0) {
                                                T->logout = -T->logout;
                                                printf("- %s", crmsg);
                                        }
                                        else
                                                printf("- %s",
                                                    fmttime(T->logout,
                                                    fulltime | TIMEONLY));
                                        delta = T->logout - bp->ut_xtime;
                                        if (delta < SECSPERDAY)
                                                printf("  (%s)\n",
                                                    fmttime(delta,
                                                    fulltime | TIMEONLY | GMT));
                                        else
                                                printf(" (%ld+%s)\n",
                                                    delta / SECSPERDAY,
                                                    fmttime(delta,
                                                    fulltime | TIMEONLY | GMT));
                                }
                                if (maxrec != -1 && !--maxrec)
                                        return;
                        }
                        T->logout = bp->ut_xtime;
                }
        }
        fulltime = 1;   /* show full time */
        crmsg = fmttime(bufx[1].ut_xtime, FULLTIME);
        if ((ct = strrchr(file, '/')) != NULL)
                ct++;
        printf("\n%s begins %s\n", ct ? ct : file, crmsg);
}

/*
 * wantx --
 *      see if want this entry
 */
static int
wantx(struct utmpx *bp, int check)
{
        ARG *step;

        if (check) {
                /*
                 * when uucp and ftp log in over a network, the entry in
                 * the utmpx file is the name plus their process id.  See
                 * etc/ftpd.c and usr.bin/uucp/uucpd.c for more information.
                 */
                if (!strncmp(bp->ut_line, "ftp", sizeof("ftp") - 1))
                        bp->ut_line[3] = '\0';
                else if (!strncmp(bp->ut_line, "uucp", sizeof("uucp") - 1))
                        bp->ut_line[4] = '\0';
        }
        if (!arglist)
                return (YES);

        for (step = arglist; step; step = step->next)
                switch(step->type) {
                case HOST_TYPE:
                        if (!strncasecmp(step->name, bp->ut_host, UTX_HOSTSIZE))
                                return (YES);
                        break;
                case TTY_TYPE:
                        if (!strncmp(step->name, bp->ut_line, UTX_LINESIZE))
                                return (YES);
                        break;
                case USER_TYPE:
                        if (!strncmp(step->name, bp->ut_name, UTX_USERSIZE))
                                return (YES);
                        break;
        }
        return (NO);
}

/*
 * onintrx --
 *      on interrupt, we inform the user how far we've gotten
 */
static void
onintrx(int signo)
{

        printf("\ninterrupted %s\n", fmttime(bufx[1].ut_xtime,
            FULLTIME));
        if (signo == SIGINT)
                exit(1);
        (void)fflush(stdout);           /* fix required for rsh */
}