/*      $OpenBSD: util.c,v 1.29 2025/08/20 10:40:21 henning Exp $ */

/*
 * Copyright (c) 2004 Alexander Guy <alexander.guy@andern.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <fcntl.h>
#include <limits.h>
#include <math.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>

#include "ntpd.h"

double
gettime_corrected(void)
{
        return (gettime() + getoffset());
}

double
getoffset(void)
{
        struct timeval  tv;
        if (adjtime(NULL, &tv) == -1)
                return (0.0);
        return (tv.tv_sec + 1.0e-6 * tv.tv_usec);
}

double
gettime(void)
{
        struct timeval  tv;

        if (gettimeofday(&tv, NULL) == -1)
                fatal("gettimeofday");

        return (gettime_from_timeval(&tv));
}

double
gettime_from_timeval(struct timeval *tv)
{
        /*
         * Account for overflow on OSes that have a 32-bit time_t.
         */
        return ((uint64_t)tv->tv_sec + JAN_1970 + 1.0e-6 * tv->tv_usec);
}

time_t
getmonotime(void)
{
        struct timespec ts;

        if (clock_gettime(CLOCK_MONOTONIC, &ts) != 0)
                fatal("clock_gettime");

        return (ts.tv_sec);
}


int
d_to_tv(double d, struct timeval *tv)
{
        /* this assumes a 64 bit time_t */
        if (!isfinite(d) || d > (double)LLONG_MAX || d < (double)LLONG_MIN)
                return (-1);

        tv->tv_sec = d;
        tv->tv_usec = (d - tv->tv_sec) * 1000000;
        while (tv->tv_usec < 0) {
                tv->tv_usec += 1000000;
                tv->tv_sec -= 1;
        }

        return (0);
}

double
lfp_to_d(struct l_fixedpt lfp)
{
        double  base, ret;

        lfp.int_partl = ntohl(lfp.int_partl);
        lfp.fractionl = ntohl(lfp.fractionl);

        /* see comment in ntp.h */
        base = NTP_ERA;
        if (lfp.int_partl <= INT32_MAX)
                base++; 
        ret = base * SECS_IN_ERA;
        ret += (double)(lfp.int_partl) + ((double)lfp.fractionl / L_DENOMINATOR);

        return (ret);
}

struct l_fixedpt
d_to_lfp(double d)
{
        struct l_fixedpt        lfp;

        while (d > SECS_IN_ERA)
                d -= SECS_IN_ERA;
        lfp.int_partl = htonl((u_int32_t)d);
        lfp.fractionl = htonl((u_int32_t)((d - (u_int32_t)d) * L_DENOMINATOR));

        return (lfp);
}

double
sfp_to_d(struct s_fixedpt sfp)
{
        double  ret;

        sfp.int_parts = ntohs(sfp.int_parts);
        sfp.fractions = ntohs(sfp.fractions);

        ret = (double)(sfp.int_parts) + ((double)sfp.fractions / S_DENOMINATOR);

        return (ret);
}

struct s_fixedpt
d_to_sfp(double d)
{
        struct s_fixedpt        sfp;

        sfp.int_parts = htons((u_int16_t)d);
        sfp.fractions = htons((u_int16_t)((d - (u_int16_t)d) * S_DENOMINATOR));

        return (sfp);
}

char *
print_rtable(int r)
{
        static char b[11];

        b[0] = 0;
        if (r > 0)
                snprintf(b, sizeof(b), "rtable %d", r);

        return (b);
}

const char *
log_sockaddr(struct sockaddr *sa)
{
        static char     buf[NI_MAXHOST];

        if (getnameinfo(sa, SA_LEN(sa), buf, sizeof(buf), NULL, 0,
            NI_NUMERICHOST))
                return ("(unknown)");
        else
                return (buf);
}

const char *
log_ntp_addr(struct ntp_addr *addr)
{
        if (addr == NULL)
                return ("(unknown)");
        return log_sockaddr((struct sockaddr *)&addr->ss);
}

pid_t
start_child(char *pname, int cfd, int argc, char **argv)
{
        char            **nargv;
        int               nargc, i;
        pid_t             pid;

        /* Prepare the child process new argv. */
        nargv = calloc(argc + 3, sizeof(char *));
        if (nargv == NULL)
                fatal("%s: calloc", __func__);

        /* Copy the program name first. */
        nargc = 0;
        nargv[nargc++] = argv[0];

        /* Set the process name and copy the original args. */
        nargv[nargc++] = "-P";
        nargv[nargc++] = pname;
        for (i = 1; i < argc; i++)
                nargv[nargc++] = argv[i];

        nargv[nargc] = NULL;

        switch (pid = fork()) {
        case -1:
                fatal("%s: fork", __func__);
                break;
        case 0:
                /* Prepare the parent socket and execute. */
                if (cfd != PARENT_SOCK_FILENO) {
                        if (dup2(cfd, PARENT_SOCK_FILENO) == -1)
                                fatal("dup2");
                } else if (fcntl(cfd, F_SETFD, 0) == -1)
                        fatal("fcntl");

                execvp(argv[0], nargv);
                fatal("%s: execvp", __func__);
                break;

        default:
                /* Close child's socket end. */
                close(cfd);
                break;
        }

        free(nargv);
        return (pid);
}

int
sanitize_argv(int *argc, char ***argv)
{
        char            **nargv;
        int               nargc;
        int               i;

        /*
         * We need at least three arguments:
         * Example: '/usr/sbin/ntpd' '-P' 'foobar'.
         */
        if (*argc < 3)
                return (-1);

        *argc -= 2;

        /* Allocate new arguments vector and copy pointers. */
        nargv = calloc((*argc) + 1, sizeof(char *));
        if (nargv == NULL)
                return (-1);

        nargc = 0;
        nargv[nargc++] = (*argv)[0];
        for (i = 1; i < *argc; i++)
                nargv[nargc++] = (*argv)[i + 2];

        nargv[nargc] = NULL;
        *argv = nargv;
        return (0);
}