xref: /curl/lib/parsedate.c (revision fbf5d507)
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7  *
8  * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
9  *
10  * This software is licensed as described in the file COPYING, which
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16  * furnished to do so, under the terms of the COPYING file.
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18  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19  * KIND, either express or implied.
20  *
21  * SPDX-License-Identifier: curl
22  *
23  ***************************************************************************/
24 /*
25   A brief summary of the date string formats this parser groks:
26 
27   RFC 2616 3.3.1
28 
29   Sun, 06 Nov 1994 08:49:37 GMT  ; RFC 822, updated by RFC 1123
30   Sunday, 06-Nov-94 08:49:37 GMT ; RFC 850, obsoleted by RFC 1036
31   Sun Nov  6 08:49:37 1994       ; ANSI C's asctime() format
32 
33   we support dates without week day name:
34 
35   06 Nov 1994 08:49:37 GMT
36   06-Nov-94 08:49:37 GMT
37   Nov  6 08:49:37 1994
38 
39   without the time zone:
40 
41   06 Nov 1994 08:49:37
42   06-Nov-94 08:49:37
43 
44   weird order:
45 
46   1994 Nov 6 08:49:37  (GNU date fails)
47   GMT 08:49:37 06-Nov-94 Sunday
48   94 6 Nov 08:49:37    (GNU date fails)
49 
50   time left out:
51 
52   1994 Nov 6
53   06-Nov-94
54   Sun Nov 6 94
55 
56   unusual separators:
57 
58   1994.Nov.6
59   Sun/Nov/6/94/GMT
60 
61   commonly used time zone names:
62 
63   Sun, 06 Nov 1994 08:49:37 CET
64   06 Nov 1994 08:49:37 EST
65 
66   time zones specified using RFC822 style:
67 
68   Sun, 12 Sep 2004 15:05:58 -0700
69   Sat, 11 Sep 2004 21:32:11 +0200
70 
71   compact numerical date strings:
72 
73   20040912 15:05:58 -0700
74   20040911 +0200
75 
76 */
77 
78 #include "curl_setup.h"
79 
80 #include <limits.h>
81 
82 #include <curl/curl.h>
83 #include "strcase.h"
84 #include "warnless.h"
85 #include "parsedate.h"
86 
87 /*
88  * parsedate()
89  *
90  * Returns:
91  *
92  * PARSEDATE_OK     - a fine conversion
93  * PARSEDATE_FAIL   - failed to convert
94  * PARSEDATE_LATER  - time overflow at the far end of time_t
95  * PARSEDATE_SOONER - time underflow at the low end of time_t
96  */
97 
98 static int parsedate(const char *date, time_t *output);
99 
100 #define PARSEDATE_OK     0
101 #define PARSEDATE_FAIL   -1
102 #define PARSEDATE_LATER  1
103 #define PARSEDATE_SOONER 2
104 
105 #if !defined(CURL_DISABLE_PARSEDATE) || !defined(CURL_DISABLE_FTP) || \
106   !defined(CURL_DISABLE_FILE)
107 /* These names are also used by FTP and FILE code */
108 const char * const Curl_wkday[] =
109 {"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"};
110 const char * const Curl_month[]=
111 { "Jan", "Feb", "Mar", "Apr", "May", "Jun",
112   "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" };
113 #endif
114 
115 #ifndef CURL_DISABLE_PARSEDATE
116 static const char * const weekday[] =
117 { "Monday", "Tuesday", "Wednesday", "Thursday",
118   "Friday", "Saturday", "Sunday" };
119 
120 struct tzinfo {
121   char name[5];
122   int offset; /* +/- in minutes */
123 };
124 
125 /* Here's a bunch of frequently used time zone names. These were supported
126    by the old getdate parser. */
127 #define tDAYZONE -60       /* offset for daylight savings time */
128 static const struct tzinfo tz[]= {
129   {"GMT", 0},              /* Greenwich Mean */
130   {"UT",  0},              /* Universal Time */
131   {"UTC", 0},              /* Universal (Coordinated) */
132   {"WET", 0},              /* Western European */
133   {"BST", 0 tDAYZONE},     /* British Summer */
134   {"WAT", 60},             /* West Africa */
135   {"AST", 240},            /* Atlantic Standard */
136   {"ADT", 240 tDAYZONE},   /* Atlantic Daylight */
137   {"EST", 300},            /* Eastern Standard */
138   {"EDT", 300 tDAYZONE},   /* Eastern Daylight */
139   {"CST", 360},            /* Central Standard */
140   {"CDT", 360 tDAYZONE},   /* Central Daylight */
141   {"MST", 420},            /* Mountain Standard */
142   {"MDT", 420 tDAYZONE},   /* Mountain Daylight */
143   {"PST", 480},            /* Pacific Standard */
144   {"PDT", 480 tDAYZONE},   /* Pacific Daylight */
145   {"YST", 540},            /* Yukon Standard */
146   {"YDT", 540 tDAYZONE},   /* Yukon Daylight */
147   {"HST", 600},            /* Hawaii Standard */
148   {"HDT", 600 tDAYZONE},   /* Hawaii Daylight */
149   {"CAT", 600},            /* Central Alaska */
150   {"AHST", 600},           /* Alaska-Hawaii Standard */
151   {"NT",  660},            /* Nome */
152   {"IDLW", 720},           /* International Date Line West */
153   {"CET", -60},            /* Central European */
154   {"MET", -60},            /* Middle European */
155   {"MEWT", -60},           /* Middle European Winter */
156   {"MEST", -60 tDAYZONE},  /* Middle European Summer */
157   {"CEST", -60 tDAYZONE},  /* Central European Summer */
158   {"MESZ", -60 tDAYZONE},  /* Middle European Summer */
159   {"FWT", -60},            /* French Winter */
160   {"FST", -60 tDAYZONE},   /* French Summer */
161   {"EET", -120},           /* Eastern Europe, USSR Zone 1 */
162   {"WAST", -420},          /* West Australian Standard */
163   {"WADT", -420 tDAYZONE}, /* West Australian Daylight */
164   {"CCT", -480},           /* China Coast, USSR Zone 7 */
165   {"JST", -540},           /* Japan Standard, USSR Zone 8 */
166   {"EAST", -600},          /* Eastern Australian Standard */
167   {"EADT", -600 tDAYZONE}, /* Eastern Australian Daylight */
168   {"GST", -600},           /* Guam Standard, USSR Zone 9 */
169   {"NZT", -720},           /* New Zealand */
170   {"NZST", -720},          /* New Zealand Standard */
171   {"NZDT", -720 tDAYZONE}, /* New Zealand Daylight */
172   {"IDLE", -720},          /* International Date Line East */
173   /* Next up: Military timezone names. RFC822 allowed these, but (as noted in
174      RFC 1123) had their signs wrong. Here we use the correct signs to match
175      actual military usage.
176    */
177   {"A",  1 * 60},         /* Alpha */
178   {"B",  2 * 60},         /* Bravo */
179   {"C",  3 * 60},         /* Charlie */
180   {"D",  4 * 60},         /* Delta */
181   {"E",  5 * 60},         /* Echo */
182   {"F",  6 * 60},         /* Foxtrot */
183   {"G",  7 * 60},         /* Golf */
184   {"H",  8 * 60},         /* Hotel */
185   {"I",  9 * 60},         /* India */
186   /* "J", Juliet is not used as a timezone, to indicate the observer's local
187      time */
188   {"K", 10 * 60},         /* Kilo */
189   {"L", 11 * 60},         /* Lima */
190   {"M", 12 * 60},         /* Mike */
191   {"N",  -1 * 60},         /* November */
192   {"O",  -2 * 60},         /* Oscar */
193   {"P",  -3 * 60},         /* Papa */
194   {"Q",  -4 * 60},         /* Quebec */
195   {"R",  -5 * 60},         /* Romeo */
196   {"S",  -6 * 60},         /* Sierra */
197   {"T",  -7 * 60},         /* Tango */
198   {"U",  -8 * 60},         /* Uniform */
199   {"V",  -9 * 60},         /* Victor */
200   {"W", -10 * 60},         /* Whiskey */
201   {"X", -11 * 60},         /* X-ray */
202   {"Y", -12 * 60},         /* Yankee */
203   {"Z", 0},                /* Zulu, zero meridian, a.k.a. UTC */
204 };
205 
206 /* returns:
207    -1 no day
208    0 monday - 6 sunday
209 */
210 
checkday(const char * check,size_t len)211 static int checkday(const char *check, size_t len)
212 {
213   int i;
214   const char * const *what;
215   if(len > 3)
216     what = &weekday[0];
217   else if(len == 3)
218     what = &Curl_wkday[0];
219   else
220     return -1; /* too short */
221   for(i = 0; i < 7; i++) {
222     size_t ilen = strlen(what[0]);
223     if((ilen == len) &&
224        strncasecompare(check, what[0], len))
225       return i;
226     what++;
227   }
228   return -1;
229 }
230 
checkmonth(const char * check,size_t len)231 static int checkmonth(const char *check, size_t len)
232 {
233   int i;
234   const char * const *what = &Curl_month[0];
235   if(len != 3)
236     return -1; /* not a month */
237 
238   for(i = 0; i < 12; i++) {
239     if(strncasecompare(check, what[0], 3))
240       return i;
241     what++;
242   }
243   return -1; /* return the offset or -1, no real offset is -1 */
244 }
245 
246 /* return the time zone offset between GMT and the input one, in number
247    of seconds or -1 if the timezone was not found/legal */
248 
checktz(const char * check,size_t len)249 static int checktz(const char *check, size_t len)
250 {
251   unsigned int i;
252   const struct tzinfo *what = tz;
253   if(len > 4) /* longer than any valid timezone */
254     return -1;
255 
256   for(i = 0; i < sizeof(tz)/sizeof(tz[0]); i++) {
257     size_t ilen = strlen(what->name);
258     if((ilen == len) &&
259        strncasecompare(check, what->name, len))
260       return what->offset*60;
261     what++;
262   }
263   return -1;
264 }
265 
skip(const char ** date)266 static void skip(const char **date)
267 {
268   /* skip everything that are not letters or digits */
269   while(**date && !ISALNUM(**date))
270     (*date)++;
271 }
272 
273 enum assume {
274   DATE_MDAY,
275   DATE_YEAR,
276   DATE_TIME
277 };
278 
279 /*
280  * time2epoch: time stamp to seconds since epoch in GMT time zone. Similar to
281  * mktime but for GMT only.
282  */
time2epoch(int sec,int min,int hour,int mday,int mon,int year)283 static time_t time2epoch(int sec, int min, int hour,
284                          int mday, int mon, int year)
285 {
286   static const int month_days_cumulative [12] =
287     { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
288   int leap_days = year - (mon <= 1);
289   leap_days = ((leap_days / 4) - (leap_days / 100) + (leap_days / 400)
290                - (1969 / 4) + (1969 / 100) - (1969 / 400));
291   return ((((time_t) (year - 1970) * 365
292             + leap_days + month_days_cumulative[mon] + mday - 1) * 24
293            + hour) * 60 + min) * 60 + sec;
294 }
295 
296 /* Returns the value of a single-digit or two-digit decimal number, return
297    then pointer to after the number. The 'date' pointer is known to point to a
298    digit. */
oneortwodigit(const char * date,const char ** endp)299 static int oneortwodigit(const char *date, const char **endp)
300 {
301   int num = date[0] - '0';
302   if(ISDIGIT(date[1])) {
303     *endp = &date[2];
304     return num*10 + (date[1] - '0');
305   }
306   *endp = &date[1];
307   return num;
308 }
309 
310 
311 /* HH:MM:SS or HH:MM and accept single-digits too */
match_time(const char * date,int * h,int * m,int * s,char ** endp)312 static bool match_time(const char *date,
313                        int *h, int *m, int *s, char **endp)
314 {
315   const char *p;
316   int hh, mm, ss = 0;
317   hh = oneortwodigit(date, &p);
318   if((hh < 24) && (*p == ':') && ISDIGIT(p[1])) {
319     mm = oneortwodigit(&p[1], &p);
320     if(mm < 60) {
321       if((*p == ':') && ISDIGIT(p[1])) {
322         ss = oneortwodigit(&p[1], &p);
323         if(ss <= 60) {
324           /* valid HH:MM:SS */
325           goto match;
326         }
327       }
328       else {
329         /* valid HH:MM */
330         goto match;
331       }
332     }
333   }
334   return FALSE; /* not a time string */
335 match:
336   *h = hh;
337   *m = mm;
338   *s = ss;
339   *endp = (char *)p;
340   return TRUE;
341 }
342 
343 /*
344  * parsedate()
345  *
346  * Returns:
347  *
348  * PARSEDATE_OK     - a fine conversion
349  * PARSEDATE_FAIL   - failed to convert
350  * PARSEDATE_LATER  - time overflow at the far end of time_t
351  * PARSEDATE_SOONER - time underflow at the low end of time_t
352  */
353 
354 /* Wednesday is the longest name this parser knows about */
355 #define NAME_LEN 12
356 
parsedate(const char * date,time_t * output)357 static int parsedate(const char *date, time_t *output)
358 {
359   time_t t = 0;
360   int wdaynum = -1;  /* day of the week number, 0-6 (mon-sun) */
361   int monnum = -1;   /* month of the year number, 0-11 */
362   int mdaynum = -1; /* day of month, 1 - 31 */
363   int hournum = -1;
364   int minnum = -1;
365   int secnum = -1;
366   int yearnum = -1;
367   int tzoff = -1;
368   enum assume dignext = DATE_MDAY;
369   const char *indate = date; /* save the original pointer */
370   int part = 0; /* max 6 parts */
371 
372   while(*date && (part < 6)) {
373     bool found = FALSE;
374 
375     skip(&date);
376 
377     if(ISALPHA(*date)) {
378       /* a name coming up */
379       size_t len = 0;
380       const char *p = date;
381       while(ISALPHA(*p) && (len < NAME_LEN)) {
382         p++;
383         len++;
384       }
385 
386       if(len != NAME_LEN) {
387         if(wdaynum == -1) {
388           wdaynum = checkday(date, len);
389           if(wdaynum != -1)
390             found = TRUE;
391         }
392         if(!found && (monnum == -1)) {
393           monnum = checkmonth(date, len);
394           if(monnum != -1)
395             found = TRUE;
396         }
397 
398         if(!found && (tzoff == -1)) {
399           /* this just must be a time zone string */
400           tzoff = checktz(date, len);
401           if(tzoff != -1)
402             found = TRUE;
403         }
404       }
405       if(!found)
406         return PARSEDATE_FAIL; /* bad string */
407 
408       date += len;
409     }
410     else if(ISDIGIT(*date)) {
411       /* a digit */
412       int val;
413       char *end;
414       if((secnum == -1) &&
415          match_time(date, &hournum, &minnum, &secnum, &end)) {
416         /* time stamp */
417         date = end;
418       }
419       else {
420         long lval;
421         int error;
422         int old_errno;
423 
424         old_errno = errno;
425         errno = 0;
426         lval = strtol(date, &end, 10);
427         error = errno;
428         if(errno != old_errno)
429           errno = old_errno;
430 
431         if(error)
432           return PARSEDATE_FAIL;
433 
434 #if LONG_MAX != INT_MAX
435         if((lval > (long)INT_MAX) || (lval < (long)INT_MIN))
436           return PARSEDATE_FAIL;
437 #endif
438 
439         val = curlx_sltosi(lval);
440 
441         if((tzoff == -1) &&
442            ((end - date) == 4) &&
443            (val <= 1400) &&
444            (indate < date) &&
445            ((date[-1] == '+' || date[-1] == '-'))) {
446           /* four digits and a value less than or equal to 1400 (to take into
447              account all sorts of funny time zone diffs) and it is preceded
448              with a plus or minus. This is a time zone indication. 1400 is
449              picked since +1300 is frequently used and +1400 is mentioned as
450              an edge number in the document "ISO C 200X Proposal: Timezone
451              Functions" at http://david.tribble.com/text/c0xtimezone.html If
452              anyone has a more authoritative source for the exact maximum time
453              zone offsets, please speak up! */
454           found = TRUE;
455           tzoff = (val/100 * 60 + val%100)*60;
456 
457           /* the + and - prefix indicates the local time compared to GMT,
458              this we need their reversed math to get what we want */
459           tzoff = date[-1]=='+' ? -tzoff : tzoff;
460         }
461 
462         if(((end - date) == 8) &&
463            (yearnum == -1) &&
464            (monnum == -1) &&
465            (mdaynum == -1)) {
466           /* 8 digits, no year, month or day yet. This is YYYYMMDD */
467           found = TRUE;
468           yearnum = val/10000;
469           monnum = (val%10000)/100-1; /* month is 0 - 11 */
470           mdaynum = val%100;
471         }
472 
473         if(!found && (dignext == DATE_MDAY) && (mdaynum == -1)) {
474           if((val > 0) && (val < 32)) {
475             mdaynum = val;
476             found = TRUE;
477           }
478           dignext = DATE_YEAR;
479         }
480 
481         if(!found && (dignext == DATE_YEAR) && (yearnum == -1)) {
482           yearnum = val;
483           found = TRUE;
484           if(yearnum < 100) {
485             if(yearnum > 70)
486               yearnum += 1900;
487             else
488               yearnum += 2000;
489           }
490           if(mdaynum == -1)
491             dignext = DATE_MDAY;
492         }
493 
494         if(!found)
495           return PARSEDATE_FAIL;
496 
497         date = end;
498       }
499     }
500 
501     part++;
502   }
503 
504   if(-1 == secnum)
505     secnum = minnum = hournum = 0; /* no time, make it zero */
506 
507   if((-1 == mdaynum) ||
508      (-1 == monnum) ||
509      (-1 == yearnum))
510     /* lacks vital info, fail */
511     return PARSEDATE_FAIL;
512 
513 #ifdef HAVE_TIME_T_UNSIGNED
514   if(yearnum < 1970) {
515     /* only positive numbers cannot return earlier */
516     *output = TIME_T_MIN;
517     return PARSEDATE_SOONER;
518   }
519 #endif
520 
521 #if (SIZEOF_TIME_T < 5)
522 
523 #ifdef HAVE_TIME_T_UNSIGNED
524   /* an unsigned 32-bit time_t can only hold dates to 2106 */
525   if(yearnum > 2105) {
526     *output = TIME_T_MAX;
527     return PARSEDATE_LATER;
528   }
529 #else
530   /* a signed 32-bit time_t can only hold dates to the beginning of 2038 */
531   if(yearnum > 2037) {
532     *output = TIME_T_MAX;
533     return PARSEDATE_LATER;
534   }
535   if(yearnum < 1903) {
536     *output = TIME_T_MIN;
537     return PARSEDATE_SOONER;
538   }
539 #endif
540 
541 #else
542   /* The Gregorian calendar was introduced 1582 */
543   if(yearnum < 1583)
544     return PARSEDATE_FAIL;
545 #endif
546 
547   if((mdaynum > 31) || (monnum > 11) ||
548      (hournum > 23) || (minnum > 59) || (secnum > 60))
549     return PARSEDATE_FAIL; /* clearly an illegal date */
550 
551   /* time2epoch() returns a time_t. time_t is often 32 bits, sometimes even on
552      architectures that feature a 64 bits 'long' but ultimately time_t is the
553      correct data type to use.
554   */
555   t = time2epoch(secnum, minnum, hournum, mdaynum, monnum, yearnum);
556 
557   /* Add the time zone diff between local time zone and GMT. */
558   if(tzoff == -1)
559     tzoff = 0;
560 
561   if((tzoff > 0) && (t > TIME_T_MAX - tzoff)) {
562     *output = TIME_T_MAX;
563     return PARSEDATE_LATER; /* time_t overflow */
564   }
565 
566   t += tzoff;
567 
568   *output = t;
569 
570   return PARSEDATE_OK;
571 }
572 #else
573 /* disabled */
parsedate(const char * date,time_t * output)574 static int parsedate(const char *date, time_t *output)
575 {
576   (void)date;
577   *output = 0;
578   return PARSEDATE_OK; /* a lie */
579 }
580 #endif
581 
curl_getdate(const char * p,const time_t * now)582 time_t curl_getdate(const char *p, const time_t *now)
583 {
584   time_t parsed = -1;
585   int rc = parsedate(p, &parsed);
586   (void)now; /* legacy argument from the past that we ignore */
587 
588   if(rc == PARSEDATE_OK) {
589     if(parsed == -1)
590       /* avoid returning -1 for a working scenario */
591       parsed++;
592     return parsed;
593   }
594   /* everything else is fail */
595   return -1;
596 }
597 
598 /* Curl_getdate_capped() differs from curl_getdate() in that this will return
599    TIME_T_MAX in case the parsed time value was too big, instead of an
600    error. */
601 
Curl_getdate_capped(const char * p)602 time_t Curl_getdate_capped(const char *p)
603 {
604   time_t parsed = -1;
605   int rc = parsedate(p, &parsed);
606 
607   switch(rc) {
608   case PARSEDATE_OK:
609     if(parsed == -1)
610       /* avoid returning -1 for a working scenario */
611       parsed++;
612     return parsed;
613   case PARSEDATE_LATER:
614     /* this returns the maximum time value */
615     return parsed;
616   default:
617     return -1; /* everything else is fail */
618   }
619   /* UNREACHABLE */
620 }
621 
622 /*
623  * Curl_gmtime() is a gmtime() replacement for portability. Do not use the
624  * gmtime_r() or gmtime() functions anywhere else but here.
625  *
626  */
627 
Curl_gmtime(time_t intime,struct tm * store)628 CURLcode Curl_gmtime(time_t intime, struct tm *store)
629 {
630   const struct tm *tm;
631 #ifdef HAVE_GMTIME_R
632   /* thread-safe version */
633   tm = (struct tm *)gmtime_r(&intime, store);
634 #else
635   /* !checksrc! disable BANNEDFUNC 1 */
636   tm = gmtime(&intime);
637   if(tm)
638     *store = *tm; /* copy the pointed struct to the local copy */
639 #endif
640 
641   if(!tm)
642     return CURLE_BAD_FUNCTION_ARGUMENT;
643   return CURLE_OK;
644 }
645