/*      $NetBSD: lastcomm.c,v 1.23 2012/01/31 21:53:42 wiz Exp $        */

/*
 * Copyright (c) 1980, 1993
 *      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/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1980, 1993\
 The Regents of the University of California.  All rights reserved.");
#endif /* not lint */

#ifndef lint
#if 0
static char sccsid[] = "@(#)lastcomm.c  8.2 (Berkeley) 4/29/95";
#endif
__RCSID("$NetBSD: lastcomm.c,v 1.23 2012/01/31 21:53:42 wiz Exp $");
#endif /* not lint */

#include <sys/param.h>
#include <sys/stat.h>
#include <sys/acct.h>

#include <ctype.h>
#include <err.h>
#include <fcntl.h>
#include <math.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <struct.h>
#include <time.h>
#include <tzfile.h>
#include <unistd.h>
#include <utmp.h>
#include "pathnames.h"

static time_t            expand(u_int);
static char             *flagbits(int);
static const char       *getdev(dev_t);
static int               requested(char *[], const struct acct *);
static void              usage(void) __dead;

int
main(int argc, char *argv[])
{
        char *p;
        struct acct ab;
        struct stat sb;
        FILE *fp;
        off_t size;
        time_t t;
        double delta;
        int ch, wflag, lwidth;
        const char *acctfile = _PATH_ACCT;

        setprogname(argv[0]);
        wflag = 0;
        lwidth = -6;

        while ((ch = getopt(argc, argv, "f:w")) != -1)
                switch((char)ch) {
                case 'f':
                        acctfile = optarg;
                        break;
                case 'w':
                        wflag = 1;
                        break;
                case '?':
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        /* Open the file. */
        if ((fp = fopen(acctfile, "r")) == NULL || fstat(fileno(fp), &sb))
                err(1, "%s", acctfile);

        /*
         * Round off to integral number of accounting records, probably
         * not necessary, but it doesn't hurt.
         */
        size = sb.st_size - sb.st_size % sizeof(ab);

        /* Check if any records to display. */
        if (size < (off_t)sizeof(ab))
                return 0;

        size -= sizeof(ab);
        if (fseeko(fp, size, SEEK_SET) == -1)
                err(1, "%s", acctfile);

        lwidth = (int)fldsiz(acct, ac_comm) - ((wflag)? 0: 6);
        for (;;) {
                if (fread(&ab, sizeof(ab), 1, fp) != 1)
                        err(1, "%s", acctfile);

                if (ab.ac_comm[0] == '\0') {
                        ab.ac_comm[0] = '?';
                        ab.ac_comm[1] = '\0';
                } else
                        for (p = &ab.ac_comm[0];
                            p < &ab.ac_comm[fldsiz(acct, ac_comm)] && *p; ++p)
                                if (!isprint((unsigned char)*p))
                                        *p = '?';
                if (!*argv || requested(argv, &ab)) {

                        if (!wflag)
                                ab.ac_comm[10] = '\0';
                        t = expand(ab.ac_utime) + expand(ab.ac_stime);
                        (void)printf(
                            "%-*.*s %-7s %-*.*s %-*.*s %6.2f secs %.16s",
                            lwidth, lwidth,
                            ab.ac_comm, flagbits(ab.ac_flag),
                            UT_NAMESIZE, UT_NAMESIZE,
                            user_from_uid(ab.ac_uid, 0), UT_LINESIZE,
                            UT_LINESIZE, getdev(ab.ac_tty),
                            t / (double)AHZ, ctime(&ab.ac_btime));
                        delta = expand(ab.ac_etime) / (double)AHZ;
                        (void)printf(" (%1.0f:%02.0f:%05.2f)\n",
                            floor(delta / SECSPERHOUR),
                            floor(fmod(delta, SECSPERHOUR) / SECSPERMIN),
                            fmod(delta, SECSPERMIN));
                }
                /* are we at the beginning of the file yet? */
                if (size == 0)
                        break;
                /* seek backward over the one we read and the next to read */
                if (fseeko(fp, 2 * -(off_t)sizeof(ab), SEEK_CUR) == -1)
                        err(1, "%s", acctfile);
                /* and account for its size */
                size -= sizeof(ab);
        }
        return 0;
}

static time_t
expand(u_int t)
{
        time_t nt;

        nt = t & 017777;
        t >>= 13;
        while (t) {
                t--;
                nt <<= 3;
        }
        return nt;
}

static char *
flagbits(int f)
{
        static char flags[20] = "-";
        char *p;

#define BIT(flag, ch)   if (f & flag) *p++ = ch

        p = flags + 1;
        BIT(ASU, 'S');
        BIT(AFORK, 'F');
        BIT(ACOMPAT, 'C');
        BIT(ACORE, 'D');
        BIT(AXSIG, 'X');
        *p = '\0';
        return flags;
}

static int
requested(char *argv[], const struct acct *acp)
{
        do {
                if (!strcmp(user_from_uid(acp->ac_uid, 0), *argv))
                        return 1;
                if (!strcmp(getdev(acp->ac_tty), *argv))
                        return 1;
                if (!strncmp(acp->ac_comm, *argv, fldsiz(acct, ac_comm)))
                        return 1;
        } while (*++argv);
        return 0;
}

static const char *
getdev(dev_t dev)
{
        static dev_t lastdev = NODEV;
        static const char *lastname;

        if (dev == NODEV)                       /* Special case. */
                return "__";
        if (dev == lastdev)                     /* One-element cache. */
                return lastname;
        if ((lastname = devname(dev, S_IFCHR)) != NULL)
                return lastname;
        return "??";
}

static void
usage(void)
{
        (void)fprintf(stderr,
            "Usage: %s [-w] [-f file] [command ...] [user ...] [terminal ...]\n",
            getprogname());
        exit(1);
}