/* $NetBSD: date.c,v 1.70 2024/09/17 15:25:39 kre Exp $ */

/*
 * Copyright (c) 1985, 1987, 1988, 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.
 */

#if HAVE_NBTOOL_CONFIG_H
#include "nbtool_config.h"
#endif

#include <sys/cdefs.h>
#ifndef lint
__COPYRIGHT(
"@(#) Copyright (c) 1985, 1987, 1988, 1993\
 The Regents of the University of California.  All rights reserved.");
#endif /* not lint */

#ifndef lint
#if 0
static char sccsid[] = "@(#)date.c      8.2 (Berkeley) 4/28/95";
#else
__RCSID("$NetBSD: date.c,v 1.70 2024/09/17 15:25:39 kre Exp $");
#endif
#endif /* not lint */

#include <sys/param.h>
#include <sys/time.h>

#include <ctype.h>
#include <err.h>
#include <fcntl.h>
#include <errno.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <time.h>
#include <tzfile.h>
#include <unistd.h>
#include <util.h>
#if !HAVE_NBTOOL_CONFIG_H
#include <utmpx.h>
#endif

#include "extern.h"

static time_t tval;
static int Rflag, aflag, jflag, rflag, nflag;

__dead static void badcanotime(const char *, const char *, size_t);
static void setthetime(const char *);
__dead static void usage(void);

#if HAVE_NBTOOL_CONFIG_H
static int parse_iso_datetime(time_t *, const char *);
#else
static char *fmt;
#endif

#if !defined(isleap)
# define isleap(y)   (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
#endif

int
main(int argc, char *argv[])
{
        char *buf;
        size_t bufsiz;
        const char *format;
        int ch;
        long long val;
        struct tm *tm;
        char *default_tz;

        setprogname(argv[0]);
        (void)setlocale(LC_ALL, "");

        default_tz = getenv("TZ");

        while ((ch = getopt(argc, argv, "ad:f:jnRr:Uuz:")) != -1) {
                switch (ch) {
                case 'a':               /* adjust time slowly */
                        aflag = 1;
                        nflag = 1;
                        break;
                case 'd':
                        rflag = 1;
#ifdef HAVE_NBTOOL_CONFIG_H
                        if (parse_iso_datetime(&tval, optarg))
                                break;
                        errx(EXIT_FAILURE,
                            "-d only supports ISO format in the tool version");
                        break;
#else
                        errno = 0;
                        tval = parsedate(optarg, NULL, NULL);
                        if (tval == -1 && errno != 0) {
                                errx(EXIT_FAILURE,
                                    "%s: Unrecognized date format", optarg);
                        }
                        break;
                case 'f':
                        fmt = optarg;
                        break;
#endif
                case 'j':               /* don't set time */
                        jflag = 1;
                        break;
                case 'n':               /* don't set network */
                        nflag = 1;
                        break;
                case 'R':               /* RFC-5322 email format */
                        Rflag = 1;
                        break;
                case 'r':               /* user specified seconds */
                        if (optarg[0] == '\0') {
                                errx(EXIT_FAILURE, "<empty>: Invalid number");
                        }
                        errno = 0;
                        val = strtoll(optarg, &buf, 0);
                        if (errno) {
                                err(EXIT_FAILURE, "%s", optarg);
                        }
                        if (optarg[0] == '\0' || *buf != '\0') {
                                errx(EXIT_FAILURE,
                                    "%s: Invalid number", optarg);
                        }
                        rflag = 1;
                        tval = (time_t)val;
                        break;
                case 'U':               /* reset to default timezone */
                        if (default_tz)
                                (void)setenv("TZ", default_tz, 1);
                        else
                                (void)unsetenv("TZ");
                        break;
                case 'u':               /* do everything in UTC */
                        (void)setenv("TZ", "UTC0", 1);
                        break;
                case 'z':
                        if (optarg[0] == '\0')
                                (void)unsetenv("TZ");
                        else
                                (void)setenv("TZ", optarg, 1);
                        break;
                default:
                        usage();
                }
        }
        argc -= optind;
        argv += optind;

        if (!rflag && time(&tval) == -1)
                err(EXIT_FAILURE, "time");


        /* allow the operands in any order */
        if (*argv && **argv == '+') {
                format = *argv;
                ++argv;
        } else if (Rflag) {
                (void)setlocale(LC_TIME, "C");
                format = "+%a, %-e %b %Y %H:%M:%S %z";
        } else
                format = "+%a %b %e %H:%M:%S %Z %Y";

        if (*argv) {
                setthetime(*argv);
                ++argv;
#ifndef HAVE_NBTOOL_CONFIG_H
        } else if (fmt) {
                usage();
#endif
        }

        if (*argv && **argv == '+')
                format = *argv;

        if ((buf = malloc(bufsiz = 1024)) == NULL)
                goto bad;

        if ((tm = localtime(&tval)) == NULL)
                err(EXIT_FAILURE, "%lld: localtime", (long long)tval);

        while (strftime(buf, bufsiz, format, tm) == 0)
                if ((buf = realloc(buf, bufsiz <<= 1)) == NULL)
                        goto bad;

        (void)printf("%s\n", buf + 1);
        free(buf);
        return 0;
bad:
        err(EXIT_FAILURE, "Cannot allocate format buffer");
}

static void
badcanotime(const char *msg, const char *val, size_t where)
{
        warnx("%s in canonical time", msg);
        warnx("%s", val);
        warnx("%*s", (int)where + 1, "^");
        usage();
}

#define ATOI2(s) ((s) += 2, ((s)[-2] - '0') * 10 + ((s)[-1] - '0'))

#if HAVE_NBTOOL_CONFIG_H

inline static int
digitstring(const char *s, int len)
{
        while (--len > 0) {
                if (!isdigit(*(unsigned char *)s))
                        return 0;
                s++;
        }
        return 1;
}

static int
parse_iso_datetime(time_t * res, const char * string)
{
        struct tm tm;
        time_t t;

        memset(&tm, 0, sizeof tm);

        if (!digitstring(string, 4))
                return 0;
        tm.tm_year = ATOI2(string) * 100;
        tm.tm_year += ATOI2(string);
        tm.tm_year -= 1900;

        if (*string == '-')
                string++;

        if (!digitstring(string, 2))
                return 0;

        tm.tm_mon = ATOI2(string);
        if (tm.tm_mon < 1 || tm.tm_mon > 12)
                return 0;
        tm.tm_mon--;

        if (*string == '-')
                string++;

        if (!digitstring(string, 2))
                return 0;

        tm.tm_mday = ATOI2(string);
        if (tm.tm_mday < 1)
                return 0;
        switch (tm.tm_mon) {
        case 0: case 2: case 4: case 6: case 7: case 9: case 11:
                if (tm.tm_mday > 31)
                        return 0;
                break;
        case 3: case 5: case 8: case 10:
                if (tm.tm_mday > 30)
                        return 0;
                break;
        case 1:
                if (tm.tm_mday > 28 + isleap(tm.tm_year + 1900))
                        return 0;
                break;
        default:
                abort();
        }

        do {
                if (*string == '\0')
                        break;
                if (*string == 'T' || *string == 't' || *string == ' ' ||
                    *string == '-')
                        string++;

                if (!digitstring(string, 2))
                        return 0;
                tm.tm_hour = ATOI2(string);
                if (tm.tm_hour > 23)
                        return 0;

                if (*string == '\0')
                        break;
                if (*string == ':')
                        string++;

                if (!digitstring(string, 2))
                        return 0;
                tm.tm_min = ATOI2(string);
                if (tm.tm_min >= 60)
                        return 0;

                if (*string == '\0')
                        break;
                if (*string == ':')
                        string++;

                if (!digitstring(string, 2))
                        return 0;
                tm.tm_sec = ATOI2(string);
                if (tm.tm_sec >= 60)
                        return 0;
        } while (0);

        if (*string != '\0')
                return 0;

        tm.tm_isdst = -1;
        tm.tm_wday = -1;

        t = mktime(&tm);
        if (tm.tm_wday == -1)
                return 0;

        *res = t;
        return 1;
}

#endif  /*NBTOOL*/

static void
setthetime(const char *p)
{
        struct timeval tv;
        time_t new_time;
        struct tm *lt;
        const char *dot, *t, *op;
        size_t len;
        int yearset;

        if ((lt = localtime(&tval)) == NULL)
                err(EXIT_FAILURE, "%lld: localtime", (long long)tval);

        lt->tm_isdst = -1;                      /* Divine correct DST */

#ifndef HAVE_NBTOOL_CONFIG_H
        if (fmt) {
                t = strptime(p, fmt, lt);
                if (t == NULL) {
                        warnx("Failed conversion of ``%s''"
                            " using format ``%s''\n", p, fmt);
                } else if (*t != '\0')
                        warnx("Ignoring %zu extraneous"
                                " characters in date string (%s)",
                                strlen(t), t);
                goto setit;
        }
        if (getenv("POSIXLY_CORRECT") != NULL) {
                int yrdigs;
                const char * const e = "Bad POSIX format date ``%s''";

                t = strptime(p, "%m%d%H%M", lt);
                if (t == NULL)
                        errx(EXIT_FAILURE, e, p);
                if (*t != '\0') {
                        yrdigs = strspn(t, "0123456789");
                        if (yrdigs != 2 && yrdigs != 4)
                                errx(EXIT_FAILURE, e, p);
                        t = strptime(t, yrdigs == 2 ? "%y" : "%Y", lt);
                        if (t == NULL || *t != '\0')
                                errx(EXIT_FAILURE, e, p);
                }
                goto setit;
        }
#endif
        for (t = p, dot = NULL; *t; ++t) {
                if (*t == '.') {
                        if (dot == NULL) {
                                dot = t;
                        } else {
                                badcanotime("Unexpected dot", p, t - p);
                        }
                } else if (!isdigit((unsigned char)*t)) {
                        badcanotime("Expected digit", p, t - p);
                }
        }


        if (dot != NULL) {                      /* .ss */
                len = strlen(dot);
                if (len > 3) {
                        badcanotime("Unexpected digit after seconds field",
                                    p, strlen(p) - 1);
                } else if (len < 3) {
                        badcanotime("Expected digit in seconds field",
                                    p, strlen(p));
                }
                ++dot;
                lt->tm_sec = ATOI2(dot);
                if (lt->tm_sec > 61)
                        badcanotime("Seconds out of range", p, strlen(p) - 1);
        } else {
                len = 0;
                lt->tm_sec = 0;
        }

        op = p;
        yearset = 0;
        switch (strlen(p) - len) {
        case 12:                                /* cc */
                lt->tm_year = ATOI2(p) * 100 - TM_YEAR_BASE;
                if (lt->tm_year < 0)
                        badcanotime("Year before 1900", op, p - op + 1);
                yearset = 1;
                /* FALLTHROUGH */
        case 10:                                /* yy */
                if (yearset) {
                        lt->tm_year += ATOI2(p);
                } else {
                        yearset = ATOI2(p);
                        if (yearset < 69)
                                lt->tm_year = yearset + 2000 - TM_YEAR_BASE;
                        else
                                lt->tm_year = yearset + 1900 - TM_YEAR_BASE;
                }
                /* FALLTHROUGH */
        case 8:                                 /* mm */
                lt->tm_mon = ATOI2(p);
                if (lt->tm_mon > 12 || lt->tm_mon == 0)
                        badcanotime("Month out of range", op, p - op - 1);
                --lt->tm_mon;                   /* time struct is 0 - 11 */
                /* FALLTHROUGH */
        case 6:                                 /* dd */
                lt->tm_mday = ATOI2(p);
                switch (lt->tm_mon) {
                case 0:
                case 2:
                case 4:
                case 6:
                case 7:
                case 9:
                case 11:
                        if (lt->tm_mday > 31 || lt->tm_mday == 0)
                                badcanotime("Day out of range (max 31)",
                                            op, p - op - 1);
                        break;
                case 3:
                case 5:
                case 8:
                case 10:
                        if (lt->tm_mday > 30 || lt->tm_mday == 0)
                                badcanotime("Day out of range (max 30)",
                                            op, p - op - 1);
                        break;
                case 1:
                        if (isleap(lt->tm_year + TM_YEAR_BASE)) {
                                if (lt->tm_mday > 29 || lt->tm_mday == 0) {
                                        badcanotime("Day out of range "
                                                    "(max 29)",
                                                    op, p - op - 1);
                                }
                        } else {
                                if (lt->tm_mday > 28 || lt->tm_mday == 0) {
                                        badcanotime("Day out of range "
                                                    "(max 28)",
                                                    op, p - op - 1);
                                }
                        }
                        break;
                default:
                        /*
                         * If the month was given, it's already been
                         * checked.  If a bad value came back from
                         * localtime, something's badly broken.
                         * (make this an assertion?)
                         */
                        errx(EXIT_FAILURE, "localtime gave invalid month %d",
                            lt->tm_mon);
                }
                /* FALLTHROUGH */
        case 4:                                 /* hh */
                lt->tm_hour = ATOI2(p);
                if (lt->tm_hour > 23)
                        badcanotime("Hour out of range", op, p - op - 1);
                /* FALLTHROUGH */
        case 2:                                 /* mm */
                lt->tm_min = ATOI2(p);
                if (lt->tm_min > 59)
                        badcanotime("Minute out of range", op, p - op - 1);
                break;
        case 0:                                 /* was just .sss */
                if (len != 0)
                        break;
                /* FALLTHROUGH */
        default:
            if (strlen(p) - len > 12) {
                    badcanotime("Too many digits", p, 12);
            } else {
                    badcanotime("Not enough digits", p, strlen(p) - len);
            }
        }
setit:
        /* convert broken-down time to UTC clock time */
        if ((new_time = mktime(lt)) == -1) {
                /* Can this actually happen? */
                err(EXIT_FAILURE, "mktime");
        }

        /* if jflag is set, don't actually change the time, just return */
        if (jflag) {
                tval = new_time;
                return;
        }

        /* set the time */
#ifndef HAVE_NBTOOL_CONFIG_H
        struct utmpx utx;
        memset(&utx, 0, sizeof(utx));
        utx.ut_type = OLD_TIME;
        (void)gettimeofday(&utx.ut_tv, NULL);
        pututxline(&utx);

        if (nflag || netsettime(new_time)) {
                logwtmp("|", "date", "");
                if (aflag) {
                        tv.tv_sec = new_time - tval;
                        tv.tv_usec = 0;
                        if (adjtime(&tv, NULL))
                                err(EXIT_FAILURE, "adjtime");
                } else {
                        tval = new_time;
                        tv.tv_sec = tval;
                        tv.tv_usec = 0;
                        if (settimeofday(&tv, NULL))
                                err(EXIT_FAILURE, "settimeofday");
                }
                logwtmp("{", "date", "");
        }
        utx.ut_type = NEW_TIME;
        (void)gettimeofday(&utx.ut_tv, NULL);
        pututxline(&utx);

        if ((p = getlogin()) == NULL)
                p = "???";
        syslog(LOG_AUTH | LOG_NOTICE, "date set by %s", p);
#else
        errx(EXIT_FAILURE, "Can't set the time in the tools version");
#endif
}

static void
usage(void)
{
        (void)fprintf(stderr,
            "Usage: %s [-ajnRUu] [-d date] [-r seconds] [-z zone] [+format]",
            getprogname());
        (void)fprintf(stderr, "\n\t%*s[[[[[[CC]yy]mm]dd]HH]MM[.SS]]\n",
            (int)strlen(getprogname()), "");
        (void)fprintf(stderr,
            "       %s [-ajnRu] -f input_format new_date [+format]\n",
            getprogname());
        exit(EXIT_FAILURE);
        /* NOTREACHED */
}