/***************************************************************************

 *                                  _   _ ____  _

 *  Project                     ___| | | |  _ \| |

 *                             / __| | | | |_) | |

 *                            | (__| |_| |  _ <| |___

 *                             \___|\___/|_| \_\_____|

 *

 * Copyright (C) 1998 - 2022, Daniel Stenberg, <daniel@haxx.se>, et al.

 *

 * This software is licensed as described in the file COPYING, which

 * you should have received as part of this distribution. The terms

 * are also available at https://curl.se/docs/copyright.html.

 *

 * You may opt to use, copy, modify, merge, publish, distribute and/or sell

 * copies of the Software, and permit persons to whom the Software is

 * furnished to do so, under the terms of the COPYING file.

 *

 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY

 * KIND, either express or implied.

 *

 * SPDX-License-Identifier: curl

 *

 ***************************************************************************/

/*

  A brief summary of the date string formats this parser groks:

  RFC 2616 3.3.1

  Sun, 06 Nov 1994 08:49:37 GMT  ; RFC 822, updated by RFC 1123

  Sunday, 06-Nov-94 08:49:37 GMT ; RFC 850, obsoleted by RFC 1036

  Sun Nov  6 08:49:37 1994       ; ANSI C's asctime() format

  we support dates without week day name:

  06 Nov 1994 08:49:37 GMT

  06-Nov-94 08:49:37 GMT

  Nov  6 08:49:37 1994

  without the time zone:

  06 Nov 1994 08:49:37

  06-Nov-94 08:49:37

  weird order:

  1994 Nov 6 08:49:37  (GNU date fails)

  GMT 08:49:37 06-Nov-94 Sunday

  94 6 Nov 08:49:37    (GNU date fails)

  time left out:

  1994 Nov 6

  06-Nov-94

  Sun Nov 6 94

  unusual separators:

  1994.Nov.6

  Sun/Nov/6/94/GMT

  commonly used time zone names:

  Sun, 06 Nov 1994 08:49:37 CET

  06 Nov 1994 08:49:37 EST

  time zones specified using RFC822 style:

  Sun, 12 Sep 2004 15:05:58 -0700

  Sat, 11 Sep 2004 21:32:11 +0200

  compact numerical date strings:

  20040912 15:05:58 -0700

  20040911 +0200

*/

#include "curl_setup.h"

#include <limits.h>

#include <curl/curl.h>

#include "strcase.h"

#include "warnless.h"

#include "parsedate.h"

/*

 * parsedate()

 *

 * Returns:

 *

 * PARSEDATE_OK     - a fine conversion

 * PARSEDATE_FAIL   - failed to convert

 * PARSEDATE_LATER  - time overflow at the far end of time_t

 * PARSEDATE_SOONER - time underflow at the low end of time_t

 */

static int parsedate(const char *date, time_t *output);

#define PARSEDATE_OK     0

#define PARSEDATE_FAIL   -1

#define PARSEDATE_LATER  1

#define PARSEDATE_SOONER 2

#if !defined(CURL_DISABLE_PARSEDATE) || !defined(CURL_DISABLE_FTP) || \

  !defined(CURL_DISABLE_FILE)

/* These names are also used by FTP and FILE code */

const char * const Curl_wkday[] =

{"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"};

const char * const Curl_month[]=

{ "Jan", "Feb", "Mar", "Apr", "May", "Jun",

  "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" };

#endif

#ifndef CURL_DISABLE_PARSEDATE

static const char * const weekday[] =

{ "Monday", "Tuesday", "Wednesday", "Thursday",

  "Friday", "Saturday", "Sunday" };

struct tzinfo {

  char name[5];

  int offset; /* +/- in minutes */

};

/* Here's a bunch of frequently used time zone names. These were supported

   by the old getdate parser. */

#define tDAYZONE -60       /* offset for daylight savings time */

static const struct tzinfo tz[]= {

  {"GMT", 0},              /* Greenwich Mean */

  {"UT",  0},              /* Universal Time */

  {"UTC", 0},              /* Universal (Coordinated) */

  {"WET", 0},              /* Western European */

  {"BST", 0 tDAYZONE},     /* British Summer */

  {"WAT", 60},             /* West Africa */

  {"AST", 240},            /* Atlantic Standard */

  {"ADT", 240 tDAYZONE},   /* Atlantic Daylight */

  {"EST", 300},            /* Eastern Standard */

  {"EDT", 300 tDAYZONE},   /* Eastern Daylight */

  {"CST", 360},            /* Central Standard */

  {"CDT", 360 tDAYZONE},   /* Central Daylight */

  {"MST", 420},            /* Mountain Standard */

  {"MDT", 420 tDAYZONE},   /* Mountain Daylight */

  {"PST", 480},            /* Pacific Standard */

  {"PDT", 480 tDAYZONE},   /* Pacific Daylight */

  {"YST", 540},            /* Yukon Standard */

  {"YDT", 540 tDAYZONE},   /* Yukon Daylight */

  {"HST", 600},            /* Hawaii Standard */

  {"HDT", 600 tDAYZONE},   /* Hawaii Daylight */

  {"CAT", 600},            /* Central Alaska */

  {"AHST", 600},           /* Alaska-Hawaii Standard */

  {"NT",  660},            /* Nome */

  {"IDLW", 720},           /* International Date Line West */

  {"CET", -60},            /* Central European */

  {"MET", -60},            /* Middle European */

  {"MEWT", -60},           /* Middle European Winter */

  {"MEST", -60 tDAYZONE},  /* Middle European Summer */

  {"CEST", -60 tDAYZONE},  /* Central European Summer */

  {"MESZ", -60 tDAYZONE},  /* Middle European Summer */

  {"FWT", -60},            /* French Winter */

  {"FST", -60 tDAYZONE},   /* French Summer */

  {"EET", -120},           /* Eastern Europe, USSR Zone 1 */

  {"WAST", -420},          /* West Australian Standard */

  {"WADT", -420 tDAYZONE}, /* West Australian Daylight */

  {"CCT", -480},           /* China Coast, USSR Zone 7 */

  {"JST", -540},           /* Japan Standard, USSR Zone 8 */

  {"EAST", -600},          /* Eastern Australian Standard */

  {"EADT", -600 tDAYZONE}, /* Eastern Australian Daylight */

  {"GST", -600},           /* Guam Standard, USSR Zone 9 */

  {"NZT", -720},           /* New Zealand */

  {"NZST", -720},          /* New Zealand Standard */

  {"NZDT", -720 tDAYZONE}, /* New Zealand Daylight */

  {"IDLE", -720},          /* International Date Line East */

  /* Next up: Military timezone names. RFC822 allowed these, but (as noted in

     RFC 1123) had their signs wrong. Here we use the correct signs to match

     actual military usage.

   */

  {"A",  1 * 60},         /* Alpha */

  {"B",  2 * 60},         /* Bravo */

  {"C",  3 * 60},         /* Charlie */

  {"D",  4 * 60},         /* Delta */

  {"E",  5 * 60},         /* Echo */

  {"F",  6 * 60},         /* Foxtrot */

  {"G",  7 * 60},         /* Golf */

  {"H",  8 * 60},         /* Hotel */

  {"I",  9 * 60},         /* India */

  /* "J", Juliet is not used as a timezone, to indicate the observer's local

     time */

  {"K", 10 * 60},         /* Kilo */

  {"L", 11 * 60},         /* Lima */

  {"M", 12 * 60},         /* Mike */

  {"N",  -1 * 60},         /* November */

  {"O",  -2 * 60},         /* Oscar */

  {"P",  -3 * 60},         /* Papa */

  {"Q",  -4 * 60},         /* Quebec */

  {"R",  -5 * 60},         /* Romeo */

  {"S",  -6 * 60},         /* Sierra */

  {"T",  -7 * 60},         /* Tango */

  {"U",  -8 * 60},         /* Uniform */

  {"V",  -9 * 60},         /* Victor */

  {"W", -10 * 60},         /* Whiskey */

  {"X", -11 * 60},         /* X-ray */

  {"Y", -12 * 60},         /* Yankee */

  {"Z", 0},                /* Zulu, zero meridian, a.k.a. UTC */

};

/* returns:

   -1 no day

   0 monday - 6 sunday

*/

static int checkday(const char *check, size_t len)

{

  int i;

  const char * const *what;

  bool found = FALSE;

  if(len > 3)

    what = &weekday[0];

  else

    what = &Curl_wkday[0];

  for(i = 0; i<7; i++) {

    if(strcasecompare(check, what[0])) {

      found = TRUE;

      break;

    }

    what++;

  }

  return found?i:-1;

}

static int checkmonth(const char *check)

{

  int i;

  const char * const *what;

  bool found = FALSE;

  what = &Curl_month[0];

  for(i = 0; i<12; i++) {

    if(strcasecompare(check, what[0])) {

      found = TRUE;

      break;

    }

    what++;

  }

  return found?i:-1; /* return the offset or -1, no real offset is -1 */

}

/* return the time zone offset between GMT and the input one, in number

   of seconds or -1 if the timezone wasn't found/legal */

static int checktz(const char *check)

{

  unsigned int i;

  const struct tzinfo *what;

  bool found = FALSE;

  what = tz;

  for(i = 0; i< sizeof(tz)/sizeof(tz[0]); i++) {

    if(strcasecompare(check, what->name)) {

      found = TRUE;

      break;

    }

    what++;

  }

  return found?what->offset*60:-1;

}

static void skip(const char **date)

{

  /* skip everything that aren't letters or digits */

  while(**date && !ISALNUM(**date))

    (*date)++;

}

enum assume {

  DATE_MDAY,

  DATE_YEAR,

  DATE_TIME

};

/*

 * time2epoch: time stamp to seconds since epoch in GMT time zone.  Similar to

 * mktime but for GMT only.

 */

static time_t time2epoch(int sec, int min, int hour,

                         int mday, int mon, int year)

{

  static const int month_days_cumulative [12] =

    { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };

  int leap_days = year - (mon <= 1);

  leap_days = ((leap_days / 4) - (leap_days / 100) + (leap_days / 400)

               - (1969 / 4) + (1969 / 100) - (1969 / 400));

  return ((((time_t) (year - 1970) * 365

            + leap_days + month_days_cumulative[mon] + mday - 1) * 24

           + hour) * 60 + min) * 60 + sec;

}

/*

 * parsedate()

 *

 * Returns:

 *

 * PARSEDATE_OK     - a fine conversion

 * PARSEDATE_FAIL   - failed to convert

 * PARSEDATE_LATER  - time overflow at the far end of time_t

 * PARSEDATE_SOONER - time underflow at the low end of time_t

 */

static int parsedate(const char *date, time_t *output)

{

  time_t t = 0;

  int wdaynum = -1;  /* day of the week number, 0-6 (mon-sun) */

  int monnum = -1;   /* month of the year number, 0-11 */

  int mdaynum = -1; /* day of month, 1 - 31 */

  int hournum = -1;

  int minnum = -1;

  int secnum = -1;

  int yearnum = -1;

  int tzoff = -1;

  enum assume dignext = DATE_MDAY;

  const char *indate = date; /* save the original pointer */

  int part = 0; /* max 6 parts */

  while(*date && (part < 6)) {

    bool found = FALSE;

    skip(&date);

    if(ISALPHA(*date)) {

      /* a name coming up */

      char buf[32]="";

      size_t len;

      if(sscanf(date, "%31[ABCDEFGHIJKLMNOPQRSTUVWXYZ"

                          "abcdefghijklmnopqrstuvwxyz]", buf))

        len = strlen(buf);

      else

        len = 0;

      if(wdaynum == -1) {

        wdaynum = checkday(buf, len);

        if(wdaynum != -1)

          found = TRUE;

      }

      if(!found && (monnum == -1)) {

        monnum = checkmonth(buf);

        if(monnum != -1)

          found = TRUE;

      }

      if(!found && (tzoff == -1)) {

        /* this just must be a time zone string */

        tzoff = checktz(buf);

        if(tzoff != -1)

          found = TRUE;

      }

      if(!found)

        return PARSEDATE_FAIL; /* bad string */

      date += len;

    }

    else if(ISDIGIT(*date)) {

      /* a digit */

      int val;

      char *end;

      int len = 0;

      if((secnum == -1) &&

         (3 == sscanf(date, "%02d:%02d:%02d%n",

                      &hournum, &minnum, &secnum, &len))) {

        /* time stamp! */

        date += len;

      }

      else if((secnum == -1) &&

              (2 == sscanf(date, "%02d:%02d%n", &hournum, &minnum, &len))) {

        /* time stamp without seconds */

        date += len;

        secnum = 0;

      }

      else {

        long lval;

        int error;

        int old_errno;

        old_errno = errno;

        errno = 0;

        lval = strtol(date, &end, 10);

        error = errno;

        if(errno != old_errno)

          errno = old_errno;

        if(error)

          return PARSEDATE_FAIL;

#if LONG_MAX != INT_MAX

        if((lval > (long)INT_MAX) || (lval < (long)INT_MIN))

          return PARSEDATE_FAIL;

#endif

        val = curlx_sltosi(lval);

        if((tzoff == -1) &&

           ((end - date) == 4) &&

           (val <= 1400) &&

           (indate< date) &&

           ((date[-1] == '+' || date[-1] == '-'))) {

          /* four digits and a value less than or equal to 1400 (to take into

             account all sorts of funny time zone diffs) and it is preceded

             with a plus or minus. This is a time zone indication.  1400 is

             picked since +1300 is frequently used and +1400 is mentioned as

             an edge number in the document "ISO C 200X Proposal: Timezone

             Functions" at http://david.tribble.com/text/c0xtimezone.html If

             anyone has a more authoritative source for the exact maximum time

             zone offsets, please speak up! */

          found = TRUE;

          tzoff = (val/100 * 60 + val%100)*60;

          /* the + and - prefix indicates the local time compared to GMT,

             this we need their reversed math to get what we want */

          tzoff = date[-1]=='+'?-tzoff:tzoff;

        }

        if(((end - date) == 8) &&

           (yearnum == -1) &&

           (monnum == -1) &&

           (mdaynum == -1)) {

          /* 8 digits, no year, month or day yet. This is YYYYMMDD */

          found = TRUE;

          yearnum = val/10000;

          monnum = (val%10000)/100-1; /* month is 0 - 11 */

          mdaynum = val%100;

        }

        if(!found && (dignext == DATE_MDAY) && (mdaynum == -1)) {

          if((val > 0) && (val<32)) {

            mdaynum = val;

            found = TRUE;

          }

          dignext = DATE_YEAR;

        }

        if(!found && (dignext == DATE_YEAR) && (yearnum == -1)) {

          yearnum = val;

          found = TRUE;

          if(yearnum < 100) {

            if(yearnum > 70)

              yearnum += 1900;

            else

              yearnum += 2000;

          }

          if(mdaynum == -1)

            dignext = DATE_MDAY;

        }

        if(!found)

          return PARSEDATE_FAIL;

        date = end;

      }

    }

    part++;

  }

  if(-1 == secnum)

    secnum = minnum = hournum = 0; /* no time, make it zero */

  if((-1 == mdaynum) ||

     (-1 == monnum) ||

     (-1 == yearnum))

    /* lacks vital info, fail */

    return PARSEDATE_FAIL;

#ifdef HAVE_TIME_T_UNSIGNED

  if(yearnum < 1970) {

    /* only positive numbers cannot return earlier */

    *output = TIME_T_MIN;

    return PARSEDATE_SOONER;

  }

#endif

#if (SIZEOF_TIME_T < 5)

#ifdef HAVE_TIME_T_UNSIGNED

  /* an unsigned 32 bit time_t can only hold dates to 2106 */

  if(yearnum > 2105) {

    *output = TIME_T_MAX;

    return PARSEDATE_LATER;

  }

#else

  /* a signed 32 bit time_t can only hold dates to the beginning of 2038 */

  if(yearnum > 2037) {

    *output = TIME_T_MAX;

    return PARSEDATE_LATER;

  }

  if(yearnum < 1903) {

    *output = TIME_T_MIN;

    return PARSEDATE_SOONER;

  }

#endif

#else

  /* The Gregorian calendar was introduced 1582 */

  if(yearnum < 1583)

    return PARSEDATE_FAIL;

#endif

  if((mdaynum > 31) || (monnum > 11) ||

     (hournum > 23) || (minnum > 59) || (secnum > 60))

    return PARSEDATE_FAIL; /* clearly an illegal date */

  /* time2epoch() returns a time_t. time_t is often 32 bits, sometimes even on

     architectures that feature 64 bit 'long' but ultimately time_t is the

     correct data type to use.

  */

  t = time2epoch(secnum, minnum, hournum, mdaynum, monnum, yearnum);

  /* Add the time zone diff between local time zone and GMT. */

  if(tzoff == -1)

    tzoff = 0;

  if((tzoff > 0) && (t > TIME_T_MAX - tzoff)) {

    *output = TIME_T_MAX;

    return PARSEDATE_LATER; /* time_t overflow */

  }

  t += tzoff;

  *output = t;

  return PARSEDATE_OK;

}

#else

/* disabled */

static int parsedate(const char *date, time_t *output)

{

  (void)date;

  *output = 0;

  return PARSEDATE_OK; /* a lie */

}

#endif

time_t curl_getdate(const char *p, const time_t *now)

{

  time_t parsed = -1;

  int rc = parsedate(p, &parsed);

  (void)now; /* legacy argument from the past that we ignore */

  if(rc == PARSEDATE_OK) {

    if(parsed == -1)

      /* avoid returning -1 for a working scenario */

      parsed++;

    return parsed;

  }

  /* everything else is fail */

  return -1;

}

/* Curl_getdate_capped() differs from curl_getdate() in that this will return

   TIME_T_MAX in case the parsed time value was too big, instead of an

   error. */

time_t Curl_getdate_capped(const char *p)

{

  time_t parsed = -1;

  int rc = parsedate(p, &parsed);

  switch(rc) {

  case PARSEDATE_OK:

    if(parsed == -1)

      /* avoid returning -1 for a working scenario */

      parsed++;

    return parsed;

  case PARSEDATE_LATER:

    /* this returns the maximum time value */

    return parsed;

  default:

    return -1; /* everything else is fail */

  }

  /* UNREACHABLE */

}

/*

 * Curl_gmtime() is a gmtime() replacement for portability. Do not use the

 * gmtime_r() or gmtime() functions anywhere else but here.

 *

 */

CURLcode Curl_gmtime(time_t intime, struct tm *store)

{

  const struct tm *tm;

#ifdef HAVE_GMTIME_R

  /* thread-safe version */

  tm = (struct tm *)gmtime_r(&intime, store);

#else

  /* !checksrc! disable BANNEDFUNC 1 */

  tm = gmtime(&intime);

  if(tm)

    *store = *tm; /* copy the pointed struct to the local copy */

#endif

  if(!tm)

    return CURLE_BAD_FUNCTION_ARGUMENT;

  return CURLE_OK;

}