/* vi: set sw=4 ts=4: */
/*
 * Utility routines.
 *
 * Copyright (C) 2007 Denys Vlasenko
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */
#include "libbb.h"

/* Returns 0 if the time structure contains an absolute UTC time which
 * should not be subject to DST adjustment by the caller. */
int FAST_FUNC parse_datestr(const char *date_str, struct tm *ptm)
{
        char end = '\0';
        time_t t;
#if ENABLE_DESKTOP
/*
 * strptime is BIG: ~1k in uclibc, ~10k in glibc
 * We need it for 'month_name d HH:MM:SS YYYY', supported by GNU date,
 * but if we've linked it we might as well use it for everything.
 */
        static const char fmt_str[] ALIGN1 =
                "%R" "\0"               /* HH:MM */
                "%T" "\0"               /* HH:MM:SS */
                "%m.%d-%R" "\0"         /* mm.dd-HH:MM */
                "%m.%d-%T" "\0"         /* mm.dd-HH:MM:SS */
                "%Y.%m.%d-%R" "\0"      /* yyyy.mm.dd-HH:MM */
                "%Y.%m.%d-%T" "\0"      /* yyyy.mm.dd-HH:MM:SS */
                "%b %d %T %Y" "\0"      /* month_name d HH:MM:SS YYYY */
                "%Y-%m-%d %R" "\0"      /* yyyy-mm-dd HH:MM */
                "%Y-%m-%d %T" "\0"      /* yyyy-mm-dd HH:MM:SS */
# if ENABLE_FEATURE_TIMEZONE
                "%Y-%m-%d %R %z" "\0"   /* yyyy-mm-dd HH:MM TZ */
                "%Y-%m-%d %T %z" "\0"   /* yyyy-mm-dd HH:MM:SS TZ */
# endif
                "%Y-%m-%d %H" "\0"      /* yyyy-mm-dd HH */
                "%Y-%m-%d" "\0"         /* yyyy-mm-dd */
                /* extra NUL */;
        struct tm save;
        const char *fmt;
        char *endp;

        save = *ptm;
        fmt = fmt_str;
        while (*fmt) {
                endp = strptime(date_str, fmt, ptm);
                if (endp && *endp == '\0') {
# if ENABLE_FEATURE_TIMEZONE
                        if (strchr(fmt, 'z')) {
                                /* we have timezone offset: obtain Unix time_t */
                                ptm->tm_sec -= ptm->tm_gmtoff;
                                ptm->tm_isdst = 0;
                                t = timegm(ptm);
                                if (t == (time_t)-1)
                                        break;
                                /* convert Unix time_t to struct tm in user's locale */
                                goto localise;
                        }
# endif
                        return 1;
                }
                *ptm = save;
                while (*++fmt)
                        continue;
                ++fmt;
        }
#else
        const char *last_colon = strrchr(date_str, ':');

        if (last_colon != NULL) {
                /* Parse input and assign appropriately to ptm */

                /* HH:MM */
                if (sscanf(date_str, "%u:%u%c",
                                        &ptm->tm_hour,
                                        &ptm->tm_min,
                                        &end) >= 2
                ) {
                        /* no adjustments needed */
                } else
                /* mm.dd-HH:MM */
                if (sscanf(date_str, "%u.%u-%u:%u%c",
                                        &ptm->tm_mon, &ptm->tm_mday,
                                        &ptm->tm_hour, &ptm->tm_min,
                                        &end) >= 4
                ) {
                        /* Adjust month from 1-12 to 0-11 */
                        ptm->tm_mon -= 1;
                } else
                /* yyyy.mm.dd-HH:MM */
                if (sscanf(date_str, "%u.%u.%u-%u:%u%c", &ptm->tm_year,
                                        &ptm->tm_mon, &ptm->tm_mday,
                                        &ptm->tm_hour, &ptm->tm_min,
                                        &end) >= 5
                /* yyyy-mm-dd HH:MM */
                 || sscanf(date_str, "%u-%u-%u %u:%u%c", &ptm->tm_year,
                                        &ptm->tm_mon, &ptm->tm_mday,
                                        &ptm->tm_hour, &ptm->tm_min,
                                        &end) >= 5
                ) {
                        ptm->tm_year -= 1900; /* Adjust years */
                        ptm->tm_mon -= 1; /* Adjust month from 1-12 to 0-11 */
                } else
                {
                        bb_error_msg_and_die(bb_msg_invalid_date, date_str);
                }
                if (end == ':') {
                        /* xxx:SS */
                        if (sscanf(last_colon + 1, "%u%c", &ptm->tm_sec, &end) == 1)
                                end = '\0';
                        /* else end != NUL and we error out */
                }
        } else
        if (strchr(date_str, '-')
            /* Why strchr('-') check?
             * sscanf below will trash ptm->tm_year, this breaks
             * if parse_str is "10101010" (iow, "MMddhhmm" form)
             * because we destroy year. Do these sscanf
             * only if we saw a dash in parse_str.
             */
                /* yyyy-mm-dd HH */
         && (sscanf(date_str, "%u-%u-%u %u%c", &ptm->tm_year,
                                &ptm->tm_mon, &ptm->tm_mday,
                                &ptm->tm_hour,
                                &end) >= 4
                /* yyyy-mm-dd */
             || sscanf(date_str, "%u-%u-%u%c", &ptm->tm_year,
                                &ptm->tm_mon, &ptm->tm_mday,
                                &end) >= 3
            )
        ) {
                ptm->tm_year -= 1900; /* Adjust years */
                ptm->tm_mon -= 1; /* Adjust month from 1-12 to 0-11 */
        } else
#endif /* ENABLE_DESKTOP */
        if (date_str[0] == '@') {
                if (sizeof(t) <= sizeof(long))
                        t = bb_strtol(date_str + 1, NULL, 10);
                else /* time_t is 64 bits but longs are smaller */
                        t = bb_strtoll(date_str + 1, NULL, 10);
                if (!errno) {
                        struct tm *lt;
 IF_FEATURE_TIMEZONE(localise:)
                        lt = localtime(&t);
                        if (lt) {
                                *ptm = *lt;
                                return 0;
                        }
                }
                end = '1';
        } else {
                /* Googled the following on an old date manpage:
                 *
                 * The canonical representation for setting the date/time is:
                 * cc   Century (either 19 or 20)
                 * yy   Year in abbreviated form (e.g. 89, 06)
                 * mm   Numeric month, a number from 1 to 12
                 * dd   Day, a number from 1 to 31
                 * HH   Hour, a number from 0 to 23
                 * MM   Minutes, a number from 0 to 59
                 * .SS  Seconds, a number from 0 to 61 (with leap seconds)
                 * Everything but the minutes is optional
                 *
                 * "touch -t DATETIME" format: [[[[[YY]YY]MM]DD]hh]mm[.ss]
                 * Some, but not all, Unix "date DATETIME" commands
                 * move [[YY]YY] past minutes mm field (!).
                 * Coreutils date does it, and SUS mandates it.
                 * (date -s DATETIME does not support this format. lovely!)
                 * In bbox, this format is special-cased in date applet
                 * (IOW: this function assumes "touch -t" format).
                 */
                unsigned cur_year = ptm->tm_year;
                int len = strchrnul(date_str, '.') - date_str;

                /* MM[.SS] */
                if (len == 2 && sscanf(date_str, "%2u%2u%2u%2u""%2u%c" + 12,
                                        &ptm->tm_min,
                                        &end) >= 1) {
                } else
                /* HHMM[.SS] */
                if (len == 4 && sscanf(date_str, "%2u%2u%2u""%2u%2u%c" + 9,
                                        &ptm->tm_hour,
                                        &ptm->tm_min,
                                        &end) >= 2) {
                } else
                /* ddHHMM[.SS] */
                if (len == 6 && sscanf(date_str, "%2u%2u""%2u%2u%2u%c" + 6,
                                        &ptm->tm_mday,
                                        &ptm->tm_hour,
                                        &ptm->tm_min,
                                        &end) >= 3) {
                } else
                /* mmddHHMM[.SS] */
                if (len == 8 && sscanf(date_str, "%2u""%2u%2u%2u%2u%c" + 3,
                                        &ptm->tm_mon,
                                        &ptm->tm_mday,
                                        &ptm->tm_hour,
                                        &ptm->tm_min,
                                        &end) >= 4) {
                        /* Adjust month from 1-12 to 0-11 */
                        ptm->tm_mon -= 1;
                } else
                /* yymmddHHMM[.SS] */
                if (len == 10 && sscanf(date_str, "%2u%2u%2u%2u%2u%c",
                                        &ptm->tm_year,
                                        &ptm->tm_mon,
                                        &ptm->tm_mday,
                                        &ptm->tm_hour,
                                        &ptm->tm_min,
                                        &end) >= 5) {
                        /* Adjust month from 1-12 to 0-11 */
                        ptm->tm_mon -= 1;
                        if ((int)cur_year >= 50) { /* >= 1950 */
                                /* Adjust year: */
                                /* 1. Put it in the current century */
                                ptm->tm_year += (cur_year / 100) * 100;
                                /* 2. If too far in the past, +100 years */
                                if (ptm->tm_year < cur_year - 50)
                                        ptm->tm_year += 100;
                                /* 3. If too far in the future, -100 years */
                                if (ptm->tm_year > cur_year + 50)
                                        ptm->tm_year -= 100;
                        }
                } else
                /* ccyymmddHHMM[.SS] */
                if (len == 12 && sscanf(date_str, "%4u%2u%2u%2u%2u%c",
                                        &ptm->tm_year,
                                        &ptm->tm_mon,
                                        &ptm->tm_mday,
                                        &ptm->tm_hour,
                                        &ptm->tm_min,
                                        &end) >= 5) {
                        ptm->tm_year -= 1900; /* Adjust years */
                        ptm->tm_mon -= 1; /* Adjust month from 1-12 to 0-11 */
                } else {
 err:
                        bb_error_msg_and_die(bb_msg_invalid_date, date_str);
                }
                ptm->tm_sec = 0; /* assume zero if [.SS] is not given */
                if (end == '.') {
                        /* xxx.SS */
                        if (sscanf(strchr(date_str, '.') + 1, "%u%c",
                                        &ptm->tm_sec, &end) == 1)
                                end = '\0';
                        /* else end != NUL and we error out */
                }
                /* Users were confused by "date -s 20180923"
                 * working (not in the way they were expecting).
                 * It was interpreted as MMDDhhmm, and not bothered by
                 * "month #20" in the least. Prevent such cases:
                 */
                if (ptm->tm_sec > 60 /* allow "23:60" leap second */
                 || ptm->tm_min > 59
                 || ptm->tm_hour > 23
                 || ptm->tm_mday > 31
                 || ptm->tm_mon > 11 /* month# is 0..11, not 1..12 */
                ) {
                        goto err;
                }
        }
        if (end != '\0') {
                bb_error_msg_and_die(bb_msg_invalid_date, date_str);
        }
        return 1;
}

time_t FAST_FUNC validate_tm_time(const char *date_str, struct tm *ptm)
{
        time_t t = mktime(ptm);
        if (t == (time_t) -1L) {
                bb_error_msg_and_die(bb_msg_invalid_date, date_str);
        }
        return t;
}

static char* strftime_fmt(char *buf, unsigned len, time_t *tp, const char *fmt)
{
        time_t t;
        if (!tp) {
                tp = &t;
                time(tp);
        }
        /* Returns pointer to NUL */
        return buf + strftime(buf, len, fmt, localtime(tp));
}

char* FAST_FUNC strftime_HHMMSS(char *buf, unsigned len, time_t *tp)
{
        return strftime_fmt(buf, len, tp, "%H:%M:%S");
}

char* FAST_FUNC strftime_YYYYMMDDHHMMSS(char *buf, unsigned len, time_t *tp)
{
        return strftime_fmt(buf, len, tp, "%Y-%m-%d %H:%M:%S");
}

#if ENABLE_MONOTONIC_SYSCALL

/* Old glibc (< 2.3.4) does not provide this constant. We use syscall
 * directly so this definition is safe. */
#ifndef CLOCK_MONOTONIC
#define CLOCK_MONOTONIC 1
#endif

static void get_mono(struct timespec *ts)
{
        if (clock_gettime(CLOCK_MONOTONIC, ts))
                bb_simple_error_msg_and_die("clock_gettime(MONOTONIC) failed");
}
unsigned long long FAST_FUNC monotonic_ns(void)
{
        struct timespec ts;
        get_mono(&ts);
        return ts.tv_sec * 1000000000ULL + ts.tv_nsec;
}
unsigned long long FAST_FUNC monotonic_us(void)
{
        struct timespec ts;
        get_mono(&ts);
        return ts.tv_sec * 1000000ULL + ts.tv_nsec/1000;
}
unsigned long long FAST_FUNC monotonic_ms(void)
{
        struct timespec ts;
        get_mono(&ts);
        return ts.tv_sec * 1000ULL + ts.tv_nsec/1000000;
}
unsigned FAST_FUNC monotonic_sec(void)
{
        struct timespec ts;
        get_mono(&ts);
        return ts.tv_sec;
}

#else

unsigned long long FAST_FUNC monotonic_ns(void)
{
        struct timeval tv;
        xgettimeofday(&tv);
        return tv.tv_sec * 1000000000ULL + tv.tv_usec * 1000;
}
unsigned long long FAST_FUNC monotonic_us(void)
{
        struct timeval tv;
        xgettimeofday(&tv);
        return tv.tv_sec * 1000000ULL + tv.tv_usec;
}
unsigned long long FAST_FUNC monotonic_ms(void)
{
        struct timeval tv;
        xgettimeofday(&tv);
        return tv.tv_sec * 1000ULL + tv.tv_usec / 1000;
}
unsigned FAST_FUNC monotonic_sec(void)
{
        return time(NULL);
}

#endif