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curl/lib/parsedate.c
Daniel Stenberg 4d2f800677
curl.se: new home 
Closes #6172
2020-11-04 23:59:47 +01:00

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/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2020, 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.
*
***************************************************************************/
/*
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;
}
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