+++ /dev/null
-/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
-
-/***
- This file is part of systemd.
-
- Timezone file reading code from glibc 2.16.
-
- Copyright (C) 1991-2012 Free Software Foundation, Inc.
- Copyright 2012 Kay Sievers
-
- systemd 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.
-
- systemd 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 systemd; If not, see <http://www.gnu.org/licenses/>.
-***/
-#include <errno.h>
-#include <stddef.h>
-#include <stdio.h>
-#include <string.h>
-#include <time.h>
-#include <endian.h>
-#include <stdint.h>
-#include <stdbool.h>
-#include <sys/stat.h>
-
-#include "time-dst.h"
-#include "util.h"
-
-/*
- * If tzh_version is '2' or greater, the above is followed by a second instance
- * of tzhead and a second instance of the data in which each coded transition
- * time uses 8 rather than 4 chars, then a POSIX-TZ-environment-variable-style
- * string for use in handling instants after the last transition time stored in
- * the file * (with nothing between the newlines if there is no POSIX
- * representation for such instants).
- */
-#define TZ_MAGIC "TZif"
-struct tzhead {
- char tzh_magic[4]; /* TZ_MAGIC */
- char tzh_version[1]; /* '\0' or '2' as of 2005 */
- char tzh_reserved[15]; /* reserved--must be zero */
- char tzh_ttisgmtcnt[4]; /* coded number of trans. time flags */
- char tzh_ttisstdcnt[4]; /* coded number of trans. time flags */
- char tzh_leapcnt[4]; /* coded number of leap seconds */
- char tzh_timecnt[4]; /* coded number of transition times */
- char tzh_typecnt[4]; /* coded number of local time types */
- char tzh_charcnt[4]; /* coded number of abbr. chars */
-};
-
-struct ttinfo {
- long int offset; /* Seconds east of GMT. */
- unsigned char isdst; /* Used to set tm_isdst. */
- unsigned char idx; /* Index into `zone_names'. */
- unsigned char isstd; /* Transition times are in standard time. */
- unsigned char isgmt; /* Transition times are in GMT. */
-};
-
-struct leap {
- time_t transition; /* Time the transition takes effect. */
- long int change; /* Seconds of correction to apply. */
-};
-
-static inline int decode(const void *ptr) {
- return be32toh(*(int *)ptr);
-}
-
-static inline int64_t decode64(const void *ptr) {
- return be64toh(*(int64_t *)ptr);
-}
-
-int time_get_dst(time_t date, const char *tzfile,
- time_t *switch_cur, char **zone_cur, bool *dst_cur,
- time_t *switch_next, int *delta_next, char **zone_next, bool *dst_next) {
- unsigned char *type_idxs = 0;
- size_t num_types = 0;
- struct ttinfo *types = NULL;
- char *zone_names = NULL;
- struct stat st;
- size_t num_isstd, num_isgmt;
- struct tzhead tzhead;
- size_t chars;
- size_t i;
- size_t total_size;
- size_t types_idx;
- int trans_width = 4;
- size_t tzspec_len;
- size_t num_leaps;
- size_t lo, hi;
- size_t num_transitions = 0;
- _cleanup_free_ time_t *transitions = NULL;
- _cleanup_fclose_ FILE *f;
-
- f = fopen(tzfile, "re");
- if (f == NULL)
- return -errno;
-
- if (fstat(fileno(f), &st) < 0)
- return -errno;
-
-read_again:
- if (fread((void *)&tzhead, sizeof(tzhead), 1, f) != 1 ||
- memcmp(tzhead.tzh_magic, TZ_MAGIC, sizeof(tzhead.tzh_magic)) != 0)
- return -EINVAL;
-
- num_transitions = (size_t)decode(tzhead.tzh_timecnt);
- num_types = (size_t)decode(tzhead.tzh_typecnt);
- chars = (size_t)decode(tzhead.tzh_charcnt);
- num_leaps = (size_t)decode(tzhead.tzh_leapcnt);
- num_isstd = (size_t)decode(tzhead.tzh_ttisstdcnt);
- num_isgmt = (size_t)decode(tzhead.tzh_ttisgmtcnt);
-
- /* For platforms with 64-bit time_t we use the new format if available. */
- if (sizeof(time_t) == 8 && trans_width == 4 && tzhead.tzh_version[0] != '\0') {
- size_t to_skip;
-
- /* We use the 8-byte format. */
- trans_width = 8;
-
- /* Position the stream before the second header. */
- to_skip = (num_transitions * (4 + 1)
- + num_types * 6
- + chars
- + num_leaps * 8 + num_isstd + num_isgmt);
- if (fseek(f, to_skip, SEEK_CUR) != 0)
- return -EINVAL;
-
- goto read_again;
- }
-
- if (num_transitions > ((SIZE_MAX - (__alignof__(struct ttinfo) - 1)) / (sizeof(time_t) + 1)))
- return -EINVAL;
-
- total_size = num_transitions * (sizeof(time_t) + 1);
- total_size = ((total_size + __alignof__(struct ttinfo) - 1) & ~(__alignof__(struct ttinfo) - 1));
- types_idx = total_size;
- if (num_leaps > (SIZE_MAX - total_size) / sizeof(struct ttinfo))
- return -EINVAL;
-
- total_size += num_types * sizeof(struct ttinfo);
- if (chars > SIZE_MAX - total_size)
- return -EINVAL;
-
- total_size += chars;
- if (__alignof__(struct leap) - 1 > SIZE_MAX - total_size)
- return -EINVAL;
-
- total_size = ((total_size + __alignof__(struct leap) - 1) & ~(__alignof__(struct leap) - 1));
- if (num_leaps > (SIZE_MAX - total_size) / sizeof(struct leap))
- return -EINVAL;
-
- total_size += num_leaps * sizeof(struct leap);
- tzspec_len = 0;
- if (sizeof(time_t) == 8 && trans_width == 8) {
- off_t rem = st.st_size - ftello(f);
-
- if (rem < 0 || (size_t) rem < (num_transitions * (8 + 1) + num_types * 6 + chars))
- return -EINVAL;
- tzspec_len = (size_t) rem - (num_transitions * (8 + 1) + num_types * 6 + chars);
- if (num_leaps > SIZE_MAX / 12 || tzspec_len < num_leaps * 12)
- return -EINVAL;
- tzspec_len -= num_leaps * 12;
- if (tzspec_len < num_isstd)
- return -EINVAL;
- tzspec_len -= num_isstd;
- if (tzspec_len == 0 || tzspec_len - 1 < num_isgmt)
- return -EINVAL;
- tzspec_len -= num_isgmt + 1;
- if (SIZE_MAX - total_size < tzspec_len)
- return -EINVAL;
- }
-
- /* leave space for additional zone_names zero terminator */
- transitions = malloc0(total_size + tzspec_len + 1);
- if (transitions == NULL)
- return -EINVAL;
-
- type_idxs = (unsigned char *)transitions + (num_transitions
- * sizeof(time_t));
- types = (struct ttinfo *)((char *)transitions + types_idx);
- zone_names = (char *)types + num_types * sizeof(struct ttinfo);
-
- if (sizeof(time_t) == 4 || trans_width == 8) {
- if (fread(transitions, trans_width + 1, num_transitions, f) != num_transitions)
- return -EINVAL;
- } else {
- if (fread(transitions, 4, num_transitions, f) != num_transitions ||
- fread(type_idxs, 1, num_transitions, f) != num_transitions)
- return -EINVAL;
- }
-
- /* Check for bogus indices in the data file, so we can hereafter
- safely use type_idxs[T] as indices into `types' and never crash. */
- for (i = 0; i < num_transitions; ++i)
- if (type_idxs[i] >= num_types)
- return -EINVAL;
-
- if (__BYTE_ORDER == __BIG_ENDIAN ? sizeof(time_t) == 8 && trans_width == 4
- : sizeof(time_t) == 4 || trans_width == 4) {
- /* Decode the transition times, stored as 4-byte integers in
- network (big-endian) byte order. We work from the end of
- the array so as not to clobber the next element to be
- processed when sizeof (time_t) > 4. */
- i = num_transitions;
- while (i-- > 0)
- transitions[i] = decode((char *)transitions + i * 4);
- } else if (__BYTE_ORDER != __BIG_ENDIAN && sizeof(time_t) == 8) {
- /* Decode the transition times, stored as 8-byte integers in
- network (big-endian) byte order. */
- for (i = 0; i < num_transitions; ++i)
- transitions[i] = decode64((char *)transitions + i * 8);
- }
-
- for (i = 0; i < num_types; ++i) {
- unsigned char x[4];
- int c;
-
- if (fread(x, 1, sizeof(x), f) != sizeof(x))
- return -EINVAL;
- c = getc(f);
- if ((unsigned int)c > 1u)
- return -EINVAL;
- types[i].isdst = c;
- c = getc(f);
- if ((size_t) c > chars)
- /* Bogus index in data file. */
- return -EINVAL;
- types[i].idx = c;
- types[i].offset = (long int)decode(x);
- }
-
- if (fread(zone_names, 1, chars, f) != chars)
- return -EINVAL;
-
- zone_names[chars] = '\0';
-
- for (i = 0; i < num_isstd; ++i) {
- int c = getc(f);
- if (c == EOF)
- return -EINVAL;
- types[i].isstd = c != 0;
- }
-
- while (i < num_types)
- types[i++].isstd = 0;
-
- for (i = 0; i < num_isgmt; ++i) {
- int c = getc(f);
- if (c == EOF)
- return -EINVAL;
- types[i].isgmt = c != 0;
- }
-
- while (i < num_types)
- types[i++].isgmt = 0;
-
- if (num_transitions == 0)
- return -EINVAL;
-
- if (date < transitions[0] || date >= transitions[num_transitions - 1])
- return -EINVAL;
-
- /* Find the first transition after TIMER, and
- then pick the type of the transition before it. */
- lo = 0;
- hi = num_transitions - 1;
-
- /* Assume that DST is changing twice a year and guess initial
- search spot from it.
- Half of a gregorian year has on average 365.2425 * 86400 / 2
- = 15778476 seconds. */
- i = (transitions[num_transitions - 1] - date) / 15778476;
- if (i < num_transitions) {
- i = num_transitions - 1 - i;
- if (date < transitions[i]) {
- if (i < 10 || date >= transitions[i - 10]) {
- /* Linear search. */
- while (date < transitions[i - 1])
- i--;
- goto found;
- }
- hi = i - 10;
- } else {
- if (i + 10 >= num_transitions || date < transitions[i + 10]) {
- /* Linear search. */
- while (date >= transitions[i])
- i++;
- goto found;
- }
- lo = i + 10;
- }
- }
-
- /* Binary search. */
- while (lo + 1 < hi) {
- i = (lo + hi) / 2;
- if (date < transitions[i])
- hi = i;
- else
- lo = i;
- }
- i = hi;
-
-found:
- if (switch_cur)
- *switch_cur = transitions[i-1];
- if (zone_cur)
- *zone_cur = strdup(&zone_names[types[type_idxs[i - 1]].idx]);
- if (dst_cur)
- *dst_cur = types[type_idxs[i-1]].isdst;
-
- if (switch_next)
- *switch_next = transitions[i];
- if (delta_next)
- *delta_next = (types[type_idxs[i]].offset - types[type_idxs[i-1]].offset) / 60;
- if (zone_next)
- *zone_next = strdup(&zone_names[types[type_idxs[i]].idx]);
- if (dst_next)
- *dst_next = types[type_idxs[i]].isdst;
-
- return 0;
-}
~ianmdlvl / elogind.git / blobdiff