| /* Copyright (C) 1991-2018 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <ctype.h> |
| #include <errno.h> |
| #include <libc-lock.h> |
| #include <stdbool.h> |
| #include <stddef.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <time.h> |
| |
| #include <timezone/tzfile.h> |
| |
| #define SECSPERDAY ((time_t) 86400) |
| |
| char *__tzname[2] = { (char *) "GMT", (char *) "GMT" }; |
| int __daylight = 0; |
| long int __timezone = 0L; |
| |
| weak_alias (__tzname, tzname) |
| weak_alias (__daylight, daylight) |
| weak_alias (__timezone, timezone) |
| |
| /* This locks all the state variables in tzfile.c and this file. */ |
| __libc_lock_define_initialized (static, tzset_lock) |
| |
| /* This structure contains all the information about a |
| timezone given in the POSIX standard TZ envariable. */ |
| typedef struct |
| { |
| const char *name; |
| |
| /* When to change. */ |
| enum { J0, J1, M } type; /* Interpretation of: */ |
| unsigned short int m, n, d; /* Month, week, day. */ |
| int secs; /* Time of day. */ |
| |
| long int offset; /* Seconds east of GMT (west if < 0). */ |
| |
| /* We cache the computed time of change for a |
| given year so we don't have to recompute it. */ |
| time_t change; /* When to change to this zone. */ |
| int computed_for; /* Year above is computed for. */ |
| } tz_rule; |
| |
| /* tz_rules[0] is standard, tz_rules[1] is daylight. */ |
| static tz_rule tz_rules[2]; |
| |
| |
| static void compute_change (tz_rule *rule, int year) __THROW; |
| static void tzset_internal (int always); |
| |
| /* List of buffers containing time zone strings. */ |
| struct tzstring_l |
| { |
| struct tzstring_l *next; |
| size_t len; /* strlen(data) - doesn't count terminating NUL! */ |
| char data[0]; |
| }; |
| |
| static struct tzstring_l *tzstring_list; |
| |
| /* Allocate a permanent home for the first LEN characters of S. It |
| will never be moved or deallocated, but may share space with other |
| strings. Don't modify the returned string. */ |
| static char * |
| __tzstring_len (const char *s, size_t len) |
| { |
| char *p; |
| struct tzstring_l *t, *u, *new; |
| |
| /* Walk the list and look for a match. If this string is the same |
| as the end of an already-allocated string, it can share space. */ |
| for (u = t = tzstring_list; t; u = t, t = t->next) |
| if (len <= t->len) |
| { |
| p = &t->data[t->len - len]; |
| if (memcmp (s, p, len) == 0) |
| return p; |
| } |
| |
| /* Not found; allocate a new buffer. */ |
| new = malloc (sizeof (struct tzstring_l) + len + 1); |
| if (!new) |
| return NULL; |
| |
| new->next = NULL; |
| new->len = len; |
| memcpy (new->data, s, len); |
| new->data[len] = '\0'; |
| |
| if (u) |
| u->next = new; |
| else |
| tzstring_list = new; |
| |
| return new->data; |
| } |
| |
| /* Allocate a permanent home for S. It will never be moved or |
| deallocated, but may share space with other strings. Don't modify |
| the returned string. */ |
| char * |
| __tzstring (const char *s) |
| { |
| return __tzstring_len (s, strlen (s)); |
| } |
| |
| static char *old_tz; |
| |
| static void |
| update_vars (void) |
| { |
| __daylight = tz_rules[0].offset != tz_rules[1].offset; |
| __timezone = -tz_rules[0].offset; |
| __tzname[0] = (char *) tz_rules[0].name; |
| __tzname[1] = (char *) tz_rules[1].name; |
| } |
| |
| |
| static unsigned int |
| compute_offset (unsigned int ss, unsigned int mm, unsigned int hh) |
| { |
| if (ss > 59) |
| ss = 59; |
| if (mm > 59) |
| mm = 59; |
| if (hh > 24) |
| hh = 24; |
| return ss + mm * 60 + hh * 60 * 60; |
| } |
| |
| /* Parses the time zone name at *TZP, and writes a pointer to an |
| interned string to tz_rules[WHICHRULE].name. On success, advances |
| *TZP, and returns true. Returns false otherwise. */ |
| static bool |
| parse_tzname (const char **tzp, int whichrule) |
| { |
| const char *start = *tzp; |
| const char *p = start; |
| while (('a' <= *p && *p <= 'z') |
| || ('A' <= *p && *p <= 'Z')) |
| ++p; |
| size_t len = p - start; |
| if (len < 3) |
| { |
| p = *tzp; |
| if (__glibc_unlikely (*p++ != '<')) |
| return false; |
| start = p; |
| while (('a' <= *p && *p <= 'z') |
| || ('A' <= *p && *p <= 'Z') |
| || ('0' <= *p && *p <= '9') |
| || *p == '+' || *p == '-') |
| ++p; |
| len = p - start; |
| if (*p++ != '>' || len < 3) |
| return false; |
| } |
| |
| const char *name = __tzstring_len (start, len); |
| if (name == NULL) |
| return false; |
| tz_rules[whichrule].name = name; |
| |
| *tzp = p; |
| return true; |
| } |
| |
| /* Parses the time zone offset at *TZP, and writes it to |
| tz_rules[WHICHRULE].offset. Returns true if the parse was |
| successful. */ |
| static bool |
| parse_offset (const char **tzp, int whichrule) |
| { |
| const char *tz = *tzp; |
| if (whichrule == 0 |
| && (*tz == '\0' || (*tz != '+' && *tz != '-' && !isdigit (*tz)))) |
| return false; |
| |
| long sign; |
| if (*tz == '-' || *tz == '+') |
| sign = *tz++ == '-' ? 1L : -1L; |
| else |
| sign = -1L; |
| *tzp = tz; |
| |
| unsigned short int hh; |
| unsigned short mm = 0; |
| unsigned short ss = 0; |
| int consumed = 0; |
| if (sscanf (tz, "%hu%n:%hu%n:%hu%n", |
| &hh, &consumed, &mm, &consumed, &ss, &consumed) > 0) |
| tz_rules[whichrule].offset = sign * compute_offset (ss, mm, hh); |
| else |
| /* Nothing could be parsed. */ |
| if (whichrule == 0) |
| { |
| /* Standard time defaults to offset zero. */ |
| tz_rules[0].offset = 0; |
| return false; |
| } |
| else |
| /* DST defaults to one hour later than standard time. */ |
| tz_rules[1].offset = tz_rules[0].offset + (60 * 60); |
| *tzp = tz + consumed; |
| return true; |
| } |
| |
| /* Parses the standard <-> DST rules at *TZP. Updates |
| tz_rule[WHICHRULE]. On success, advances *TZP and returns true. |
| Otherwise, returns false. */ |
| static bool |
| parse_rule (const char **tzp, int whichrule) |
| { |
| const char *tz = *tzp; |
| tz_rule *tzr = &tz_rules[whichrule]; |
| |
| /* Ignore comma to support string following the incorrect |
| specification in early POSIX.1 printings. */ |
| tz += *tz == ','; |
| |
| /* Get the date of the change. */ |
| if (*tz == 'J' || isdigit (*tz)) |
| { |
| char *end; |
| tzr->type = *tz == 'J' ? J1 : J0; |
| if (tzr->type == J1 && !isdigit (*++tz)) |
| return false; |
| unsigned long int d = strtoul (tz, &end, 10); |
| if (end == tz || d > 365) |
| return false; |
| if (tzr->type == J1 && d == 0) |
| return false; |
| tzr->d = d; |
| tz = end; |
| } |
| else if (*tz == 'M') |
| { |
| tzr->type = M; |
| int consumed; |
| if (sscanf (tz, "M%hu.%hu.%hu%n", |
| &tzr->m, &tzr->n, &tzr->d, &consumed) != 3 |
| || tzr->m < 1 || tzr->m > 12 |
| || tzr->n < 1 || tzr->n > 5 || tzr->d > 6) |
| return false; |
| tz += consumed; |
| } |
| else if (*tz == '\0') |
| { |
| /* Daylight time rules in the U.S. are defined in the U.S. Code, |
| Title 15, Chapter 6, Subchapter IX - Standard Time. These |
| dates were established by Congress in the Energy Policy Act |
| of 2005 [Pub. L. no. 109-58, 119 Stat 594 (2005)]. |
| Below is the equivalent of "M3.2.0,M11.1.0" [/2 not needed |
| since 2:00AM is the default]. */ |
| tzr->type = M; |
| if (tzr == &tz_rules[0]) |
| { |
| tzr->m = 3; |
| tzr->n = 2; |
| tzr->d = 0; |
| } |
| else |
| { |
| tzr->m = 11; |
| tzr->n = 1; |
| tzr->d = 0; |
| } |
| } |
| else |
| return false; |
| |
| if (*tz != '\0' && *tz != '/' && *tz != ',') |
| return false; |
| else if (*tz == '/') |
| { |
| /* Get the time of day of the change. */ |
| int negative; |
| ++tz; |
| if (*tz == '\0') |
| return false; |
| negative = *tz == '-'; |
| tz += negative; |
| /* Default to 2:00 AM. */ |
| unsigned short hh = 2; |
| unsigned short mm = 0; |
| unsigned short ss = 0; |
| int consumed = 0; |
| sscanf (tz, "%hu%n:%hu%n:%hu%n", |
| &hh, &consumed, &mm, &consumed, &ss, &consumed);; |
| tz += consumed; |
| tzr->secs = (negative ? -1 : 1) * ((hh * 60 * 60) + (mm * 60) + ss); |
| } |
| else |
| /* Default to 2:00 AM. */ |
| tzr->secs = 2 * 60 * 60; |
| |
| tzr->computed_for = -1; |
| *tzp = tz; |
| return true; |
| } |
| |
| /* Parse the POSIX TZ-style string. */ |
| void |
| __tzset_parse_tz (const char *tz) |
| { |
| /* Clear out old state and reset to unnamed UTC. */ |
| memset (tz_rules, '\0', sizeof tz_rules); |
| tz_rules[0].name = tz_rules[1].name = ""; |
| |
| /* Get the standard timezone name. */ |
| if (parse_tzname (&tz, 0) && parse_offset (&tz, 0)) |
| { |
| /* Get the DST timezone name (if any). */ |
| if (*tz != '\0') |
| { |
| if (parse_tzname (&tz, 1)) |
| { |
| parse_offset (&tz, 1); |
| if (*tz == '\0' || (tz[0] == ',' && tz[1] == '\0')) |
| { |
| /* There is no rule. See if there is a default rule |
| file. */ |
| __tzfile_default (tz_rules[0].name, tz_rules[1].name, |
| tz_rules[0].offset, tz_rules[1].offset); |
| if (__use_tzfile) |
| { |
| free (old_tz); |
| old_tz = NULL; |
| return; |
| } |
| } |
| } |
| /* Figure out the standard <-> DST rules. */ |
| if (parse_rule (&tz, 0)) |
| parse_rule (&tz, 1); |
| } |
| else |
| { |
| /* There is no DST. */ |
| tz_rules[1].name = tz_rules[0].name; |
| tz_rules[1].offset = tz_rules[0].offset; |
| } |
| } |
| |
| update_vars (); |
| } |
| |
| /* Interpret the TZ envariable. */ |
| static void |
| tzset_internal (int always) |
| { |
| static int is_initialized; |
| const char *tz; |
| |
| if (is_initialized && !always) |
| return; |
| is_initialized = 1; |
| |
| /* Examine the TZ environment variable. */ |
| tz = getenv ("TZ"); |
| if (tz && *tz == '\0') |
| /* User specified the empty string; use UTC explicitly. */ |
| tz = "Universal"; |
| |
| /* A leading colon means "implementation defined syntax". |
| We ignore the colon and always use the same algorithm: |
| try a data file, and if none exists parse the 1003.1 syntax. */ |
| if (tz && *tz == ':') |
| ++tz; |
| |
| /* Check whether the value changed since the last run. */ |
| if (old_tz != NULL && tz != NULL && strcmp (tz, old_tz) == 0) |
| /* No change, simply return. */ |
| return; |
| |
| if (tz == NULL) |
| /* No user specification; use the site-wide default. */ |
| tz = TZDEFAULT; |
| |
| tz_rules[0].name = NULL; |
| tz_rules[1].name = NULL; |
| |
| /* Save the value of `tz'. */ |
| free (old_tz); |
| old_tz = tz ? __strdup (tz) : NULL; |
| |
| /* Try to read a data file. */ |
| __tzfile_read (tz, 0, NULL); |
| if (__use_tzfile) |
| return; |
| |
| /* No data file found. Default to UTC if nothing specified. */ |
| |
| if (tz == NULL || *tz == '\0' |
| || (TZDEFAULT != NULL && strcmp (tz, TZDEFAULT) == 0)) |
| { |
| memset (tz_rules, '\0', sizeof tz_rules); |
| tz_rules[0].name = tz_rules[1].name = "UTC"; |
| if (J0 != 0) |
| tz_rules[0].type = tz_rules[1].type = J0; |
| tz_rules[0].change = tz_rules[1].change = (time_t) -1; |
| update_vars (); |
| return; |
| } |
| |
| __tzset_parse_tz (tz); |
| } |
| |
| /* Figure out the exact time (as a time_t) in YEAR |
| when the change described by RULE will occur and |
| put it in RULE->change, saving YEAR in RULE->computed_for. */ |
| static void |
| compute_change (tz_rule *rule, int year) |
| { |
| time_t t; |
| |
| if (year != -1 && rule->computed_for == year) |
| /* Operations on times in 2 BC will be slower. Oh well. */ |
| return; |
| |
| /* First set T to January 1st, 0:00:00 GMT in YEAR. */ |
| if (year > 1970) |
| t = ((year - 1970) * 365 |
| + /* Compute the number of leapdays between 1970 and YEAR |
| (exclusive). There is a leapday every 4th year ... */ |
| + ((year - 1) / 4 - 1970 / 4) |
| /* ... except every 100th year ... */ |
| - ((year - 1) / 100 - 1970 / 100) |
| /* ... but still every 400th year. */ |
| + ((year - 1) / 400 - 1970 / 400)) * SECSPERDAY; |
| else |
| t = 0; |
| |
| switch (rule->type) |
| { |
| case J1: |
| /* Jn - Julian day, 1 == January 1, 60 == March 1 even in leap years. |
| In non-leap years, or if the day number is 59 or less, just |
| add SECSPERDAY times the day number-1 to the time of |
| January 1, midnight, to get the day. */ |
| t += (rule->d - 1) * SECSPERDAY; |
| if (rule->d >= 60 && __isleap (year)) |
| t += SECSPERDAY; |
| break; |
| |
| case J0: |
| /* n - Day of year. |
| Just add SECSPERDAY times the day number to the time of Jan 1st. */ |
| t += rule->d * SECSPERDAY; |
| break; |
| |
| case M: |
| /* Mm.n.d - Nth "Dth day" of month M. */ |
| { |
| unsigned int i; |
| int d, m1, yy0, yy1, yy2, dow; |
| const unsigned short int *myday = |
| &__mon_yday[__isleap (year)][rule->m]; |
| |
| /* First add SECSPERDAY for each day in months before M. */ |
| t += myday[-1] * SECSPERDAY; |
| |
| /* Use Zeller's Congruence to get day-of-week of first day of month. */ |
| m1 = (rule->m + 9) % 12 + 1; |
| yy0 = (rule->m <= 2) ? (year - 1) : year; |
| yy1 = yy0 / 100; |
| yy2 = yy0 % 100; |
| dow = ((26 * m1 - 2) / 10 + 1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7; |
| if (dow < 0) |
| dow += 7; |
| |
| /* DOW is the day-of-week of the first day of the month. Get the |
| day-of-month (zero-origin) of the first DOW day of the month. */ |
| d = rule->d - dow; |
| if (d < 0) |
| d += 7; |
| for (i = 1; i < rule->n; ++i) |
| { |
| if (d + 7 >= (int) myday[0] - myday[-1]) |
| break; |
| d += 7; |
| } |
| |
| /* D is the day-of-month (zero-origin) of the day we want. */ |
| t += d * SECSPERDAY; |
| } |
| break; |
| } |
| |
| /* T is now the Epoch-relative time of 0:00:00 GMT on the day we want. |
| Just add the time of day and local offset from GMT, and we're done. */ |
| |
| rule->change = t - rule->offset + rule->secs; |
| rule->computed_for = year; |
| } |
| |
| |
| /* Figure out the correct timezone for TM and set `__tzname', |
| `__timezone', and `__daylight' accordingly. */ |
| void |
| __tz_compute (time_t timer, struct tm *tm, int use_localtime) |
| { |
| compute_change (&tz_rules[0], 1900 + tm->tm_year); |
| compute_change (&tz_rules[1], 1900 + tm->tm_year); |
| |
| if (use_localtime) |
| { |
| int isdst; |
| |
| /* We have to distinguish between northern and southern |
| hemisphere. For the latter the daylight saving time |
| ends in the next year. */ |
| if (__builtin_expect (tz_rules[0].change |
| > tz_rules[1].change, 0)) |
| isdst = (timer < tz_rules[1].change |
| || timer >= tz_rules[0].change); |
| else |
| isdst = (timer >= tz_rules[0].change |
| && timer < tz_rules[1].change); |
| tm->tm_isdst = isdst; |
| tm->tm_zone = __tzname[isdst]; |
| tm->tm_gmtoff = tz_rules[isdst].offset; |
| } |
| } |
| |
| /* Reinterpret the TZ environment variable and set `tzname'. */ |
| #undef tzset |
| |
| void |
| __tzset (void) |
| { |
| __libc_lock_lock (tzset_lock); |
| |
| tzset_internal (1); |
| |
| if (!__use_tzfile) |
| { |
| /* Set `tzname'. */ |
| __tzname[0] = (char *) tz_rules[0].name; |
| __tzname[1] = (char *) tz_rules[1].name; |
| } |
| |
| __libc_lock_unlock (tzset_lock); |
| } |
| weak_alias (__tzset, tzset) |
| |
| /* Return the `struct tm' representation of *TIMER in the local timezone. |
| Use local time if USE_LOCALTIME is nonzero, UTC otherwise. */ |
| struct tm * |
| __tz_convert (const time_t *timer, int use_localtime, struct tm *tp) |
| { |
| long int leap_correction; |
| int leap_extra_secs; |
| |
| if (timer == NULL) |
| { |
| __set_errno (EINVAL); |
| return NULL; |
| } |
| |
| __libc_lock_lock (tzset_lock); |
| |
| /* Update internal database according to current TZ setting. |
| POSIX.1 8.3.7.2 says that localtime_r is not required to set tzname. |
| This is a good idea since this allows at least a bit more parallelism. */ |
| tzset_internal (tp == &_tmbuf && use_localtime); |
| |
| if (__use_tzfile) |
| __tzfile_compute (*timer, use_localtime, &leap_correction, |
| &leap_extra_secs, tp); |
| else |
| { |
| if (! __offtime (timer, 0, tp)) |
| tp = NULL; |
| else |
| __tz_compute (*timer, tp, use_localtime); |
| leap_correction = 0L; |
| leap_extra_secs = 0; |
| } |
| |
| __libc_lock_unlock (tzset_lock); |
| |
| if (tp) |
| { |
| if (! use_localtime) |
| { |
| tp->tm_isdst = 0; |
| tp->tm_zone = "GMT"; |
| tp->tm_gmtoff = 0L; |
| } |
| |
| if (__offtime (timer, tp->tm_gmtoff - leap_correction, tp)) |
| tp->tm_sec += leap_extra_secs; |
| else |
| tp = NULL; |
| } |
| |
| return tp; |
| } |
| |
| |
| libc_freeres_fn (free_mem) |
| { |
| while (tzstring_list != NULL) |
| { |
| struct tzstring_l *old = tzstring_list; |
| |
| tzstring_list = tzstring_list->next; |
| free (old); |
| } |
| free (old_tz); |
| old_tz = NULL; |
| } |