lib/rfc1123.c

   1 /*
   2  * Copyright (C) 1996-2020 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 #include "squid.h"
  10 #include "rfc1123.h"
  11
  12 /*
  13  *  Adapted from HTSUtils.c in CERN httpd 3.0 (http://info.cern.ch/httpd/)
  14  *  by Darren Hardy <hardy@cs.colorado.edu>, November 1994.
  15  */
  16 #if HAVE_STRING_H
  17 #include <string.h>
  18 #endif
  19 #if HAVE_CTYPE_H
  20 #include <ctype.h>
  21 #endif
  22 #if HAVE_TIME_H
  23 #include <time.h>
  24 #endif
  25
  26 #define RFC850_STRFTIME "%A, %d-%b-%y %H:%M:%S GMT"
  27 #define RFC1123_STRFTIME "%a, %d %b %Y %H:%M:%S GMT"
  28
  29 static int make_month(const char *s);
  30 static int make_num(const char *s);
  31
  32 static const char *month_names[12] = {
  33     "Jan", "Feb", "Mar", "Apr", "May", "Jun",
  34     "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
  35 };
  36
  37 static int
  38 make_num(const char *s)
  39 {
  40     if (*s >= '0' && *s <= '9')
  41         return 10 * (*s - '0') + *(s + 1) - '0';
  42     else
  43         return *(s + 1) - '0';
  44 }
  45
  46 static int
  47 make_month(const char *s)
  48 {
  49     int i;
  50     char month[3];
  51
  52     month[0] = xtoupper(*s);
  53     month[1] = xtolower(*(s + 1));
  54     month[2] = xtolower(*(s + 2));
  55
  56     for (i = 0; i < 12; i++)
  57         if (!strncmp(month_names[i], month, 3))
  58             return i;
  59     return -1;
  60 }
  61
  62 static int
  63 tmSaneValues(struct tm *tm)
  64 {
  65     if (tm->tm_sec < 0 || tm->tm_sec > 59)
  66         return 0;
  67     if (tm->tm_min < 0 || tm->tm_min > 59)
  68         return 0;
  69     if (tm->tm_hour < 0 || tm->tm_hour > 23)
  70         return 0;
  71     if (tm->tm_mday < 1 || tm->tm_mday > 31)
  72         return 0;
  73     if (tm->tm_mon < 0 || tm->tm_mon > 11)
  74         return 0;
  75     return 1;
  76 }
  77
  78 static struct tm *
  79 parse_date_elements(const char *day, const char *month, const char *year,
  80                     const char *aTime, const char *zone) {
  81     static struct tm tm;
  82     char *t;
  83     memset(&tm, 0, sizeof(tm));
  84
  85     if (!day || !month || !year || !aTime || (zone && strcmp(zone, "GMT")))
  86         return NULL;
  87     tm.tm_mday = atoi(day);
  88     tm.tm_mon = make_month(month);
  89     if (tm.tm_mon < 0)
  90         return NULL;
  91     tm.tm_year = atoi(year);
  92     if (strlen(year) == 4)
  93         tm.tm_year -= 1900;
  94     else if (tm.tm_year < 70)
  95         tm.tm_year += 100;
  96     else if (tm.tm_year > 19000)
  97         tm.tm_year -= 19000;
  98     tm.tm_hour = make_num(aTime);
  99     t = strchr(aTime, ':');
 100     if (!t)
 101         return NULL;
 102     t++;
 103     tm.tm_min = atoi(t);
 104     t = strchr(t, ':');
 105     if (t)
 106         tm.tm_sec = atoi(t + 1);
 107     return tmSaneValues(&tm) ? &tm : NULL;
 108 }
 109
 110 static struct tm *
 111 parse_date(const char *str) {
 112     struct tm *tm;
 113     static char tmp[64];
 114     char *t;
 115     char *wday = NULL;
 116     char *day = NULL;
 117     char *month = NULL;
 118     char *year = NULL;
 119     char *timestr = NULL;
 120     char *zone = NULL;
 121
 122     xstrncpy(tmp, str, 64);
 123
 124     for (t = strtok(tmp, ", "); t; t = strtok(NULL, ", ")) {
 125         if (xisdigit(*t)) {
 126             if (!day) {
 127                 day = t;
 128                 t = strchr(t, '-');
 129                 if (t) {
 130                     *t++ = '\0';
 131                     month = t;
 132                     t = strchr(t, '-');
 133                     if (!t)
 134                         return NULL;
 135                     *t++ = '\0';
 136                     year = t;
 137                 }
 138             } else if (strchr(t, ':'))
 139                 timestr = t;
 140             else if (!year)
 141                 year = t;
 142             else
 143                 return NULL;
 144         } else if (!wday)
 145             wday = t;
 146         else if (!month)
 147             month = t;
 148         else if (!zone)
 149             zone = t;
 150         else
 151             return NULL;
 152     }
 153     tm = parse_date_elements(day, month, year, timestr, zone);
 154
 155     return tm;
 156 }
 157
 158 time_t
 159 parse_rfc1123(const char *str)
 160 {
 161     struct tm *tm;
 162     time_t t;
 163     if (NULL == str)
 164         return -1;
 165     tm = parse_date(str);
 166     if (!tm)
 167         return -1;
 168     tm->tm_isdst = -1;
 169 #if HAVE_TIMEGM
 170     t = timegm(tm);
 171 #elif HAVE_TM_TM_GMTOFF
 172     t = mktime(tm);
 173     if (t != -1) {
 174         struct tm *local = localtime(&t);
 175         t += local->tm_gmtoff;
 176     }
 177 #else
 178     /* some systems do not have tm_gmtoff so we fake it */
 179     t = mktime(tm);
 180     if (t != -1) {
 181         time_t dst = 0;
 182 #if !(defined(_TIMEZONE) || defined(_timezone) || _SQUID_AIX_ || _SQUID_WINDOWS_ || _SQUID_SGI_)
 183         extern long timezone;
 184 #endif
 185         /*
 186          * The following assumes a fixed DST offset of 1 hour,
 187          * which is probably wrong.
 188          */
 189         if (tm->tm_isdst > 0)
 190             dst = -3600;
 191 #if defined(_timezone) || _SQUID_WINDOWS_
 192         t -= (_timezone + dst);
 193 #else
 194         t -= (timezone + dst);
 195 #endif
 196     }
 197 #endif
 198     return t;
 199 }
 200
 201 const char *
 202 mkrfc1123(time_t t)
 203 {
 204     static char buf[128];
 205
 206     struct tm *gmt = gmtime(&t);
 207
 208     buf[0] = '\0';
 209     strftime(buf, 127, RFC1123_STRFTIME, gmt);
 210     return buf;
 211 }
 212
 213 #if 0
 214 int
 215 main()
 216 {
 217     char *x;
 218     time_t t, pt;
 219
 220     t = time(NULL);
 221     x = mkrfc1123(t);
 222     printf("HTTP Time: %s\n", x);
 223
 224     pt = parse_rfc1123(x);
 225     printf("Parsed: %d vs. %d\n", pt, t);
 226 }
 227
 228 #endif
 229