/*
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * 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/param.h>
#include <sys/stat.h>
#include <sys/acct.h>

#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include "pathnames.h"

/*XXX*/#include <inttypes.h>

time_t   expand(u_int);
char    *flagbits(int);
const    char *getdev(dev_t);
int      readrec_forward(FILE *f, struct acctv3 *av3);
int      readrec_backward(FILE *f, struct acctv3 *av3);
int      requested(char *[], struct acctv3 *);
static   void usage(void);

#define AC_UTIME 1 /* user */
#define AC_STIME 2 /* system */
#define AC_ETIME 4 /* elapsed */
#define AC_CTIME 8 /* user + system time, default */

#define AC_BTIME 16 /* starting time */
#define AC_FTIME 32 /* exit time (starting time + elapsed time )*/

int
main(int argc, char *argv[])
{
        struct acctv3 ab;
        char *p;
        FILE *fp;
        int (*readrec)(FILE *f, struct acctv3 *av3);
        time_t t;
        int ch, rv;
        const char *acctfile, *format;
        char buf[1024];
        int flags = 0;

        acctfile = _PATH_ACCT;
        format = NULL;
        while ((ch = getopt(argc, argv, "f:usecSE")) != -1)
                switch((char)ch) {
                case 'f':
                        acctfile = optarg;
                        break;

                case 'u': 
                        flags |= AC_UTIME; /* user time */
                        break;
                case 's':
                        flags |= AC_STIME; /* system time */
                        break;
                case 'e':
                        flags |= AC_ETIME; /* elapsed time */
                        break;
                case 'c':
                        flags |= AC_CTIME; /* user + system time */
                        break;

                case 'S':
                        flags |= AC_BTIME; /* starting time */
                        break;
                case 'E':
                        /* exit time (starting time + elapsed time )*/
                        flags |= AC_FTIME; 
                        break;

                case '?':
                default:
                        usage();
                }

        /* default user + system time and starting time */
        if (!flags) {
            flags = AC_CTIME | AC_BTIME;
        }

        argc -= optind;
        argv += optind;

        if (argc > 0 && **argv == '+') {
                format = *argv + 1; /* skip + */
                argc--;
                argv++;
        }

        if (strcmp(acctfile, "-") == 0) {
                fp = stdin;
                readrec = readrec_forward;
        } else {
                /* Open the file. */
                if ((fp = fopen(acctfile, "r")) == NULL)
                        err(1, "could not open %s", acctfile);
                if (fseek(fp, 0l, SEEK_END) == -1)
                        err(1, "seek to end of %s failed", acctfile);
                readrec = readrec_backward;
        }

        while ((rv = readrec(fp, &ab)) == 1) {
                for (p = &ab.ac_comm[0];
                    p < &ab.ac_comm[AC_COMM_LEN] && *p; ++p)
                        if (!isprint(*p))
                                *p = '?';

                if (*argv && !requested(argv, &ab))
                        continue;

                (void)printf("%-*.*s %-7s %-*s %-8s",
                             AC_COMM_LEN, AC_COMM_LEN, ab.ac_comm,
                             flagbits(ab.ac_flagx),
                             MAXLOGNAME - 1, user_from_uid(ab.ac_uid, 0),
                             getdev(ab.ac_tty));
                
                
                /* user + system time */
                if (flags & AC_CTIME) {
                        (void)printf(" %6.3f secs", 
                            (ab.ac_utime + ab.ac_stime) / 1000000);
                }
                
                /* usr time */
                if (flags & AC_UTIME) {
                        (void)printf(" %6.3f us", ab.ac_utime / 1000000);
                }
                
                /* system time */
                if (flags & AC_STIME) {
                        (void)printf(" %6.3f sy", ab.ac_stime / 1000000);
                }
                
                /* elapsed time */
                if (flags & AC_ETIME) {
                        (void)printf(" %8.3f es", ab.ac_etime / 1000000);
                }
                
                /* starting time */
                if (flags & AC_BTIME) {
                        if (format != NULL) {
                                (void)strftime(buf, sizeof(buf), format,
                                    localtime(&ab.ac_btime));
                                (void)printf(" %s", buf);
                        } else
                                (void)printf(" %.19s", ctime(&ab.ac_btime));
                }
                
                /* exit time (starting time + elapsed time )*/
                if (flags & AC_FTIME) {
                        t = ab.ac_btime;
                        t += (time_t)(ab.ac_etime / 1000000);
                        if (format != NULL) {
                                (void)strftime(buf, sizeof(buf), format,
                                    localtime(&t));
                                (void)printf(" %s", buf);
                        } else
                                (void)printf(" %.19s", ctime(&t));
                }
                printf("\n");
        }
        if (rv == EOF)
                err(1, "read record from %s failed", acctfile);

        if (fflush(stdout))
                err(1, "stdout");
        exit(0);
}

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);
}

int
requested(char *argv[], struct acctv3 *acp)
{
        const char *p;

        do {
                p = user_from_uid(acp->ac_uid, 0);
                if (!strcmp(p, *argv))
                        return (1);
                if ((p = getdev(acp->ac_tty)) && !strcmp(p, *argv))
                        return (1);
                if (!strncmp(acp->ac_comm, *argv, AC_COMM_LEN))
                        return (1);
        } while (*++argv);
        return (0);
}

const char *
getdev(dev_t dev)
{
        static dev_t lastdev = (dev_t)-1;
        static const char *lastname;

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

static void
usage(void)
{
        (void)fprintf(stderr,
            "usage: lastcomm [-EScesu] [-f file] [+format] [command ...] "
            "[user ...] [terminal ...]\n");
        exit(1);
}