diff options
Diffstat (limited to 'src/shared/time-dst.c')
| -rw-r--r-- | src/shared/time-dst.c | 329 |
1 files changed, 0 insertions, 329 deletions
diff --git a/src/shared/time-dst.c b/src/shared/time-dst.c deleted file mode 100644 index 2797d1a796..0000000000 --- a/src/shared/time-dst.c +++ /dev/null @@ -1,329 +0,0 @@ -/*-*- 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; -} |