/* vi: set sw=4 ts=4: */
/*
 * adjtimex.c - read, and possibly modify, the Linux kernel 'timex' variables.
 *
 * Originally written: October 1997
 * Last hack: March 2001
 * Copyright 1997, 2000, 2001 Larry Doolittle <LRDoolittle@lbl.gov>
 *
 * busyboxed 20 March 2001, Larry Doolittle <ldoolitt@recycle.lbl.gov>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */
//config:config ADJTIMEX
//config:       bool "adjtimex (4.7 kb)"
//config:       default y
//config:       help
//config:       Adjtimex reads and optionally sets adjustment parameters for
//config:       the Linux clock adjustment algorithm.

//applet:IF_ADJTIMEX(APPLET_NOFORK(adjtimex, adjtimex, BB_DIR_SBIN, BB_SUID_DROP, adjtimex))

//kbuild:lib-$(CONFIG_ADJTIMEX) += adjtimex.o

//usage:#define adjtimex_trivial_usage
//usage:       "[-q] [-o OFS] [-f FREQ] [-p TCONST] [-t TICK]"
//usage:#define adjtimex_full_usage "\n\n"
//usage:       "Read or set kernel time variables. See adjtimex(2)\n"
//usage:     "\n        -q      Quiet"
//usage:     "\n        -o OFF  Time offset, microseconds"
//usage:     "\n        -f FREQ Frequency adjust, integer kernel units (65536 is 1ppm)"
//usage:     "\n        -t TICK Microseconds per tick, usually 10000"
//usage:     "\n                (positive -t or -f values make clock run faster)"
//usage:     "\n        -p TCONST"

#include "libbb.h"
#ifdef __BIONIC__
# include <linux/timex.h>
#else
# include <sys/timex.h>
#endif

static const uint16_t statlist_bit[] ALIGN2 = {
        STA_PLL,
        STA_PPSFREQ,
        STA_PPSTIME,
        STA_FLL,
        STA_INS,
        STA_DEL,
        STA_UNSYNC,
        STA_FREQHOLD,
        STA_PPSSIGNAL,
        STA_PPSJITTER,
        STA_PPSWANDER,
        STA_PPSERROR,
        STA_CLOCKERR,
        0
};
static const char statlist_name[] ALIGN1 =
        "PLL"       "\0"
        "PPSFREQ"   "\0"
        "PPSTIME"   "\0"
        "FFL"       "\0"
        "INS"       "\0"
        "DEL"       "\0"
        "UNSYNC"    "\0"
        "FREQHOLD"  "\0"
        "PPSSIGNAL" "\0"
        "PPSJITTER" "\0"
        "PPSWANDER" "\0"
        "PPSERROR"  "\0"
        "CLOCKERR"
;

static const char ret_code_descript[] ALIGN1 =
        "clock synchronized" "\0"
        "insert leap second" "\0"
        "delete leap second" "\0"
        "leap second in progress" "\0"
        "leap second has occurred" "\0"
        "clock not synchronized"
;

int adjtimex_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int adjtimex_main(int argc UNUSED_PARAM, char **argv)
{
        enum {
                OPT_quiet = 0x1
        };
        unsigned opt;
        char *opt_o, *opt_f, *opt_p, *opt_t;
        struct timex txc;
        int ret;
        const char *descript;

        memset(&txc, 0, sizeof(txc));

        opt = getopt32(argv, "^" "qo:f:p:t:"
                        "\0" "=0"/*no valid non-option args*/,
                        &opt_o, &opt_f, &opt_p, &opt_t
        );
        //if (opt & 0x1) // -q
        if (opt & 0x2) { // -o
                txc.offset = xatol(opt_o);
                txc.modes |= ADJ_OFFSET_SINGLESHOT;
        }
        if (opt & 0x4) { // -f
                txc.freq = xatol(opt_f);
                txc.modes |= ADJ_FREQUENCY;
        }
        if (opt & 0x8) { // -p
                txc.constant = xatol(opt_p);
                txc.modes |= ADJ_TIMECONST;
        }
        if (opt & 0x10) { // -t
                txc.tick = xatol(opt_t);
                txc.modes |= ADJ_TICK;
        }

        /* It's NOFORK applet because the code is very simple:
         * just some printf. No opens, no allocs.
         * If you need to make it more complex, feel free to downgrade to NOEXEC
         */

        ret = adjtimex(&txc);
        if (ret < 0)
                bb_perror_nomsg_and_die();

        if (!(opt & OPT_quiet)) {
                const char *sep;
                const char *name;
                int i;

                printf(
                        "    mode:         %d\n"
                        "-o  offset:       %ld us\n"
                        "-f  freq.adjust:  %ld (65536 = 1ppm)\n"
                        "    maxerror:     %ld\n"
                        "    esterror:     %ld\n"
                        "    status:       %d (",
                        txc.modes, txc.offset, txc.freq, txc.maxerror,
                        txc.esterror, txc.status
                );

                /* representative output of next code fragment:
                 * "PLL | PPSTIME"
                 */
                name = statlist_name;
                sep = "";
                for (i = 0; statlist_bit[i]; i++) {
                        if (txc.status & statlist_bit[i]) {
                                printf("%s%s", sep, name);
                                sep = " | ";
                        }
                        name += strlen(name) + 1;
                }

                descript = "error";
                if (ret <= 5)
                        descript = nth_string(ret_code_descript, ret);
                printf(")\n"
                        "-p  timeconstant: %ld\n"
                        "    precision:    %ld us\n"
                        "    tolerance:    %ld\n"
                        "-t  tick:         %ld us\n"
                        "    time.tv_sec:  %ld\n"
                        "    time.tv_usec: %ld\n"
                        "    return value: %d (%s)\n",
                        txc.constant,
                        txc.precision, txc.tolerance, txc.tick,
                        (long)txc.time.tv_sec, (long)txc.time.tv_usec,
                        ret, descript
                );
        }

        return 0;
}