/*************************************************************************\
*                  Copyright (C) Michael Kerrisk, 2015.                   *
*                                                                         *
* This program is free software. You may use, modify, and redistribute it *
* under the terms of the GNU General Public License as published by the   *
* Free Software Foundation, either version 3 or (at your option) any      *
* later version. This program is distributed without any warranty.  See   *
* the file COPYING.gpl-v3 for details.                                    *
\*************************************************************************/

/* Listing 28-2 */

#include <fcntl.h>
#include <time.h>
#include <sys/stat.h>
#include <sys/acct.h>
#include <limits.h>
#include "ugid_functions.h"             /* Declaration of userNameFromId() */
#include "tlpi_hdr.h"

#define TIME_BUF_SIZE 100

static long long                /* Convert comp_t value into long long */
comptToLL(comp_t ct)
{
    const int EXP_SIZE = 3;             /* 3-bit, base-8 exponent */
    const int MANTISSA_SIZE = 13;       /* Followed by 13-bit mantissa */
    const int MANTISSA_MASK = (1 << MANTISSA_SIZE) - 1;
    long long mantissa, exp;

    mantissa = ct & MANTISSA_MASK;
    exp = (ct >> MANTISSA_SIZE) & ((1 << EXP_SIZE) - 1);
    return mantissa << (exp * 3);       /* Power of 8 = left shift 3 bits */
}

int
main(int argc, char *argv[])
{
    int acctFile;
    struct acct ac;
    ssize_t numRead;
    char *s;
    char timeBuf[TIME_BUF_SIZE];
    struct tm *loc;
    time_t t;

    if (argc != 2 || strcmp(argv[1], "--help") == 0)
        usageErr("%s file\n", argv[0]);

    acctFile = open(argv[1], O_RDONLY);
    if (acctFile == -1)
        errExit("open");

    printf("command  flags   term.  user     "
            "start time            CPU   elapsed\n");
    printf("                status           "
            "                      time    time\n");

    while ((numRead = read(acctFile, &ac, sizeof(struct acct))) > 0) {
        if (numRead != sizeof(struct acct))
            fatal("partial read");

        printf("%-8.8s  ", ac.ac_comm);

        printf("%c", (ac.ac_flag & AFORK) ? 'F' : '-') ;
        printf("%c", (ac.ac_flag & ASU)   ? 'S' : '-') ;
        printf("%c", (ac.ac_flag & AXSIG) ? 'X' : '-') ;
        printf("%c", (ac.ac_flag & ACORE) ? 'C' : '-') ;

#ifdef __linux__
        printf(" %#6lx   ", (unsigned long) ac.ac_exitcode);
#else   /* Many other implementations provide ac_stat instead */
        printf(" %#6lx   ", (unsigned long) ac.ac_stat);
#endif

        s = userNameFromId(ac.ac_uid);
        printf("%-8.8s ", (s == NULL) ? "???" : s);

        t = ac.ac_btime;
        loc = localtime(&t);
        if (loc == NULL) {
            printf("???Unknown time???  ");
        } else {
            strftime(timeBuf, TIME_BUF_SIZE, "%Y-%m-%d %T ", loc);
            printf("%s ", timeBuf);
        }

        printf("%5.2f %7.2f ", (double) (comptToLL(ac.ac_utime) +
                    comptToLL(ac.ac_stime)) / sysconf(_SC_CLK_TCK),
                (double) comptToLL(ac.ac_etime) / sysconf(_SC_CLK_TCK));
        printf("\n");
    }

    if (numRead == -1)
        errExit("read");

    exit(EXIT_SUCCESS);
}