procexec/acct_view.c

This is procexec/acct_view.c (Listing 28-2, page 596), an example from the book, The Linux Programming Interface.

The source code file is copyright 2022, Michael Kerrisk, and is licensed under the GNU General Public License, version 3.

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/* acct_view.c

   Display contents of a process accounting file.
*/
#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' : '-') ;

        /* Not all implementations support AXSIG and ACORE */

#ifdef AXSIG
        printf("%c", (ac.ac_flag & AXSIG) ? 'X' : '-') ;
#else
        printf(" ");
#endif
#ifdef ACORE
        printf("%c", (ac.ac_flag & ACORE) ? 'C' : '-') ;
#else
        printf(" ");
#endif

#ifdef __linux__
        printf(" %#6lx   ", (unsigned long) ac.ac_exitcode);
#else   /* Many other implementations provide ac_stat instead */
        /* But the BSDs don't provide this field either */
#if ! defined(__FreeBSD__) && ! defined(__NetBSD__) && \
        ! defined(__APPLE__)
        printf(" %#6lx   ", (unsigned long) ac.ac_stat);
#else
        printf("          ");
#endif
#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);
}

 

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