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localtime.c
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localtime.c
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/* Convert timestamp from time_t to struct tm. */
/*
** This file is in the public domain, so clarified as of
** 1996-06-05 by Arthur David Olson.
*/
/*
** Leap second handling from Bradley White.
** POSIX-style TZ environment variable handling from Guy Harris.
*/
/*LINTLIBRARY*/
#define LOCALTIME_IMPLEMENTATION
#include "private.h"
#include "tzfile.h"
#include <fcntl.h>
#if defined THREAD_SAFE && THREAD_SAFE
# include <pthread.h>
static pthread_mutex_t locallock = PTHREAD_MUTEX_INITIALIZER;
static int lock(void) { return pthread_mutex_lock(&locallock); }
static void unlock(void) { pthread_mutex_unlock(&locallock); }
#else
static int lock(void) { return 0; }
static void unlock(void) { }
#endif
#ifndef TZ_ABBR_CHAR_SET
# define TZ_ABBR_CHAR_SET \
"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 :+-._"
#endif /* !defined TZ_ABBR_CHAR_SET */
#ifndef TZ_ABBR_ERR_CHAR
# define TZ_ABBR_ERR_CHAR '_'
#endif /* !defined TZ_ABBR_ERR_CHAR */
/*
+** Support non-POSIX platforms that distinguish between text and binary files.
*/
#ifndef O_BINARY
# define O_BINARY 0
#endif
#ifndef WILDABBR
/*
** Someone might make incorrect use of a time zone abbreviation:
** 1. They might reference tzname[0] before calling tzset (explicitly
** or implicitly).
** 2. They might reference tzname[1] before calling tzset (explicitly
** or implicitly).
** 3. They might reference tzname[1] after setting to a time zone
** in which Daylight Saving Time is never observed.
** 4. They might reference tzname[0] after setting to a time zone
** in which Standard Time is never observed.
** 5. They might reference tm.TM_ZONE after calling offtime.
** What's best to do in the above cases is open to debate;
** for now, we just set things up so that in any of the five cases
** WILDABBR is used. Another possibility: initialize tzname[0] to the
** string "tzname[0] used before set", and similarly for the other cases.
** And another: initialize tzname[0] to "ERA", with an explanation in the
** manual page of what this "time zone abbreviation" means (doing this so
** that tzname[0] has the "normal" length of three characters).
*/
# define WILDABBR " "
#endif /* !defined WILDABBR */
static const char wildabbr[] = WILDABBR;
static char const etc_utc[] = "Etc/UTC";
static char const *utc = etc_utc + sizeof "Etc/" - 1;
/*
** The DST rules to use if TZ has no rules and we can't load TZDEFRULES.
** Default to US rules as of 2017-05-07.
** POSIX does not specify the default DST rules;
** for historical reasons, US rules are a common default.
*/
#ifndef TZDEFRULESTRING
# define TZDEFRULESTRING ",M3.2.0,M11.1.0"
#endif
struct ttinfo { /* time type information */
int_fast32_t tt_utoff; /* UT offset in seconds */
bool tt_isdst; /* used to set tm_isdst */
int tt_desigidx; /* abbreviation list index */
bool tt_ttisstd; /* transition is std time */
bool tt_ttisut; /* transition is UT */
};
struct lsinfo { /* leap second information */
time_t ls_trans; /* transition time */
int_fast32_t ls_corr; /* correction to apply */
};
/* This abbreviation means local time is unspecified. */
static char const UNSPEC[] = "-00";
/* How many extra bytes are needed at the end of struct state's chars array.
This needs to be at least 1 for null termination in case the input
data isn't properly terminated, and it also needs to be big enough
for ttunspecified to work without crashing. */
enum { CHARS_EXTRA = max(sizeof UNSPEC, 2) - 1 };
/* Limit to time zone abbreviation length in POSIX-style TZ strings.
This is distinct from TZ_MAX_CHARS, which limits TZif file contents. */
#ifndef TZNAME_MAXIMUM
# define TZNAME_MAXIMUM 255
#endif
struct state {
int leapcnt;
int timecnt;
int typecnt;
int charcnt;
bool goback;
bool goahead;
time_t ats[TZ_MAX_TIMES];
unsigned char types[TZ_MAX_TIMES];
struct ttinfo ttis[TZ_MAX_TYPES];
char chars[max(max(TZ_MAX_CHARS + CHARS_EXTRA, sizeof "UTC"),
2 * (TZNAME_MAXIMUM + 1))];
struct lsinfo lsis[TZ_MAX_LEAPS];
/* The time type to use for early times or if no transitions.
It is always zero for recent tzdb releases.
It might be nonzero for data from tzdb 2018e or earlier. */
int defaulttype;
};
enum r_type {
JULIAN_DAY, /* Jn = Julian day */
DAY_OF_YEAR, /* n = day of year */
MONTH_NTH_DAY_OF_WEEK /* Mm.n.d = month, week, day of week */
};
struct rule {
enum r_type r_type; /* type of rule */
int r_day; /* day number of rule */
int r_week; /* week number of rule */
int r_mon; /* month number of rule */
int_fast32_t r_time; /* transition time of rule */
};
static struct tm *gmtsub(struct state const *, time_t const *, int_fast32_t,
struct tm *);
static bool increment_overflow(int *, int);
static bool increment_overflow_time(time_t *, int_fast32_t);
static int_fast32_t leapcorr(struct state const *, time_t);
static bool normalize_overflow32(int_fast32_t *, int *, int);
static struct tm *timesub(time_t const *, int_fast32_t, struct state const *,
struct tm *);
static bool typesequiv(struct state const *, int, int);
static bool tzparse(char const *, struct state *, struct state *);
#ifdef ALL_STATE
static struct state * lclptr;
static struct state * gmtptr;
#endif /* defined ALL_STATE */
#ifndef ALL_STATE
static struct state lclmem;
static struct state gmtmem;
static struct state *const lclptr = &lclmem;
static struct state *const gmtptr = &gmtmem;
#endif /* State Farm */
#ifndef TZ_STRLEN_MAX
# define TZ_STRLEN_MAX 255
#endif /* !defined TZ_STRLEN_MAX */
static char lcl_TZname[TZ_STRLEN_MAX + 1];
static int lcl_is_set;
/*
** Section 4.12.3 of X3.159-1989 requires that
** Except for the strftime function, these functions [asctime,
** ctime, gmtime, localtime] return values in one of two static
** objects: a broken-down time structure and an array of char.
** Thanks to Paul Eggert for noting this.
**
** This requirement was removed in C99, so support it only if requested,
** as support is more likely to lead to bugs in badly written programs.
*/
#if SUPPORT_C89
static struct tm tm;
#endif
#if 2 <= HAVE_TZNAME + TZ_TIME_T
char * tzname[2] = {
(char *) wildabbr,
(char *) wildabbr
};
#endif
#if 2 <= USG_COMPAT + TZ_TIME_T
long timezone;
int daylight;
#endif
#if 2 <= ALTZONE + TZ_TIME_T
long altzone;
#endif
/* Initialize *S to a value based on UTOFF, ISDST, and DESIGIDX. */
static void
init_ttinfo(struct ttinfo *s, int_fast32_t utoff, bool isdst, int desigidx)
{
s->tt_utoff = utoff;
s->tt_isdst = isdst;
s->tt_desigidx = desigidx;
s->tt_ttisstd = false;
s->tt_ttisut = false;
}
/* Return true if SP's time type I does not specify local time. */
static bool
ttunspecified(struct state const *sp, int i)
{
char const *abbr = &sp->chars[sp->ttis[i].tt_desigidx];
/* memcmp is likely faster than strcmp, and is safe due to CHARS_EXTRA. */
return memcmp(abbr, UNSPEC, sizeof UNSPEC) == 0;
}
static int_fast32_t
detzcode(const char *const codep)
{
register int_fast32_t result;
register int i;
int_fast32_t one = 1;
int_fast32_t halfmaxval = one << (32 - 2);
int_fast32_t maxval = halfmaxval - 1 + halfmaxval;
int_fast32_t minval = -1 - maxval;
result = codep[0] & 0x7f;
for (i = 1; i < 4; ++i)
result = (result << 8) | (codep[i] & 0xff);
if (codep[0] & 0x80) {
/* Do two's-complement negation even on non-two's-complement machines.
If the result would be minval - 1, return minval. */
result -= !TWOS_COMPLEMENT(int_fast32_t) && result != 0;
result += minval;
}
return result;
}
static int_fast64_t
detzcode64(const char *const codep)
{
register int_fast64_t result;
register int i;
int_fast64_t one = 1;
int_fast64_t halfmaxval = one << (64 - 2);
int_fast64_t maxval = halfmaxval - 1 + halfmaxval;
int_fast64_t minval = -TWOS_COMPLEMENT(int_fast64_t) - maxval;
result = codep[0] & 0x7f;
for (i = 1; i < 8; ++i)
result = (result << 8) | (codep[i] & 0xff);
if (codep[0] & 0x80) {
/* Do two's-complement negation even on non-two's-complement machines.
If the result would be minval - 1, return minval. */
result -= !TWOS_COMPLEMENT(int_fast64_t) && result != 0;
result += minval;
}
return result;
}
static void
update_tzname_etc(struct state const *sp, struct ttinfo const *ttisp)
{
#if HAVE_TZNAME
tzname[ttisp->tt_isdst] = (char *) &sp->chars[ttisp->tt_desigidx];
#endif
#if USG_COMPAT
if (!ttisp->tt_isdst)
timezone = - ttisp->tt_utoff;
#endif
#if ALTZONE
if (ttisp->tt_isdst)
altzone = - ttisp->tt_utoff;
#endif
}
/* If STDDST_MASK indicates that SP's TYPE provides useful info,
update tzname, timezone, and/or altzone and return STDDST_MASK,
diminished by the provided info if it is a specified local time.
Otherwise, return STDDST_MASK. See settzname for STDDST_MASK. */
static int
may_update_tzname_etc(int stddst_mask, struct state *sp, int type)
{
struct ttinfo *ttisp = &sp->ttis[type];
int this_bit = 1 << ttisp->tt_isdst;
if (stddst_mask & this_bit) {
update_tzname_etc(sp, ttisp);
if (!ttunspecified(sp, type))
return stddst_mask & ~this_bit;
}
return stddst_mask;
}
static void
settzname(void)
{
register struct state * const sp = lclptr;
register int i;
/* If STDDST_MASK & 1 we need info about a standard time.
If STDDST_MASK & 2 we need info about a daylight saving time.
When STDDST_MASK becomes zero we can stop looking. */
int stddst_mask = 0;
#if HAVE_TZNAME
tzname[0] = tzname[1] = (char *) (sp ? wildabbr : utc);
stddst_mask = 3;
#endif
#if USG_COMPAT
timezone = 0;
stddst_mask = 3;
#endif
#if ALTZONE
altzone = 0;
stddst_mask |= 2;
#endif
/*
** And to get the latest time zone abbreviations into tzname. . .
*/
if (sp) {
for (i = sp->timecnt - 1; stddst_mask && 0 <= i; i--)
stddst_mask = may_update_tzname_etc(stddst_mask, sp, sp->types[i]);
for (i = sp->typecnt - 1; stddst_mask && 0 <= i; i--)
stddst_mask = may_update_tzname_etc(stddst_mask, sp, i);
}
#if USG_COMPAT
daylight = stddst_mask >> 1 ^ 1;
#endif
}
/* Replace bogus characters in time zone abbreviations.
Return 0 on success, an errno value if a time zone abbreviation is
too long. */
static int
scrub_abbrs(struct state *sp)
{
int i;
/* Reject overlong abbreviations. */
for (i = 0; i < sp->charcnt - (TZNAME_MAXIMUM + 1); ) {
int len = strlen(&sp->chars[i]);
if (TZNAME_MAXIMUM < len)
return EOVERFLOW;
i += len + 1;
}
/* Replace bogus characters. */
for (i = 0; i < sp->charcnt; ++i)
if (strchr(TZ_ABBR_CHAR_SET, sp->chars[i]) == NULL)
sp->chars[i] = TZ_ABBR_ERR_CHAR;
return 0;
}
/* Input buffer for data read from a compiled tz file. */
union input_buffer {
/* The first part of the buffer, interpreted as a header. */
struct tzhead tzhead;
/* The entire buffer. */
char buf[2 * sizeof(struct tzhead) + 2 * sizeof(struct state)
+ 4 * TZ_MAX_TIMES];
};
#if defined(__BIONIC__)
// Android: there is no directory with file-per-time zone on Android,
// but we do have a system property instead.
#include <sys/system_properties.h>
#else
/* TZDIR with a trailing '/' rather than a trailing '\0'. */
static char const tzdirslash[sizeof TZDIR] = TZDIR "/";
#endif
/* Local storage needed for 'tzloadbody'. */
union local_storage {
/* The results of analyzing the file's contents after it is opened. */
struct file_analysis {
/* The input buffer. */
union input_buffer u;
/* A temporary state used for parsing a TZ string in the file. */
struct state st;
} u;
// Android-removed: There is no directory with file-per-time zone on Android.
#ifndef __BIONIC__
/* The file name to be opened. */
char fullname[max(sizeof(struct file_analysis), sizeof tzdirslash + 1024)];
#endif
};
/* Load tz data from the file named NAME into *SP. Read extended
format if DOEXTEND. Use *LSP for temporary storage. Return 0 on
success, an errno value on failure. */
static int
tzloadbody(char const *name, struct state *sp, bool doextend,
union local_storage *lsp)
{
register int i;
register int fid;
register int stored;
register ssize_t nread;
#if !defined(__BIONIC__)
register bool doaccess;
register char *fullname = lsp->fullname;
#endif
register union input_buffer *up = &lsp->u.u;
register int tzheadsize = sizeof(struct tzhead);
char system_tz_name[PROP_VALUE_MAX];
sp->goback = sp->goahead = false;
if (! name) {
#if defined(__BIONIC__)
extern void __bionic_get_system_tz(char* , size_t);
__bionic_get_system_tz(system_tz_name, sizeof(system_tz_name));
name = system_tz_name;
#else
name = TZDEFAULT;
if (! name)
return EINVAL;
#endif
}
#if defined(__BIONIC__)
extern int __bionic_open_tzdata(const char*, int32_t*);
int32_t entry_length;
fid = __bionic_open_tzdata(name, &entry_length);
#else
if (name[0] == ':')
++name;
#ifdef SUPPRESS_TZDIR
/* Do not prepend TZDIR. This is intended for specialized
applications only, due to its security implications. */
doaccess = true;
#else
doaccess = name[0] == '/';
#endif
if (!doaccess) {
char const *dot;
if (sizeof lsp->fullname - sizeof tzdirslash <= strlen(name))
return ENAMETOOLONG;
/* Create a string "TZDIR/NAME". Using sprintf here
would pull in stdio (and would fail if the
resulting string length exceeded INT_MAX!). */
memcpy(lsp->fullname, tzdirslash, sizeof tzdirslash);
strcpy(lsp->fullname + sizeof tzdirslash, name);
/* Set doaccess if NAME contains a ".." file name
component, as such a name could read a file outside
the TZDIR virtual subtree. */
for (dot = name; (dot = strchr(dot, '.')); dot++)
if ((dot == name || dot[-1] == '/') && dot[1] == '.'
&& (dot[2] == '/' || !dot[2])) {
doaccess = true;
break;
}
name = lsp->fullname;
}
if (doaccess && access(name, R_OK) != 0)
return errno;
fid = open(name, O_RDONLY | O_BINARY);
#endif
if (fid < 0)
return errno;
#if defined(__BIONIC__)
nread = TEMP_FAILURE_RETRY(read(fid, up->buf, entry_length));
#else
nread = read(fid, up->buf, sizeof up->buf);
#endif
if (nread < tzheadsize) {
int err = nread < 0 ? errno : EINVAL;
close(fid);
return err;
}
if (close(fid) < 0)
return errno;
for (stored = 4; stored <= 8; stored *= 2) {
char version = up->tzhead.tzh_version[0];
bool skip_datablock = stored == 4 && version;
int_fast32_t datablock_size;
int_fast32_t ttisstdcnt = detzcode(up->tzhead.tzh_ttisstdcnt);
int_fast32_t ttisutcnt = detzcode(up->tzhead.tzh_ttisutcnt);
int_fast64_t prevtr = -1;
int_fast32_t prevcorr;
int_fast32_t leapcnt = detzcode(up->tzhead.tzh_leapcnt);
int_fast32_t timecnt = detzcode(up->tzhead.tzh_timecnt);
int_fast32_t typecnt = detzcode(up->tzhead.tzh_typecnt);
int_fast32_t charcnt = detzcode(up->tzhead.tzh_charcnt);
char const *p = up->buf + tzheadsize;
/* Although tzfile(5) currently requires typecnt to be nonzero,
support future formats that may allow zero typecnt
in files that have a TZ string and no transitions. */
if (! (0 <= leapcnt && leapcnt < TZ_MAX_LEAPS
&& 0 <= typecnt && typecnt < TZ_MAX_TYPES
&& 0 <= timecnt && timecnt < TZ_MAX_TIMES
&& 0 <= charcnt && charcnt < TZ_MAX_CHARS
&& 0 <= ttisstdcnt && ttisstdcnt < TZ_MAX_TYPES
&& 0 <= ttisutcnt && ttisutcnt < TZ_MAX_TYPES))
return EINVAL;
datablock_size
= (timecnt * stored /* ats */
+ timecnt /* types */
+ typecnt * 6 /* ttinfos */
+ charcnt /* chars */
+ leapcnt * (stored + 4) /* lsinfos */
+ ttisstdcnt /* ttisstds */
+ ttisutcnt); /* ttisuts */
if (nread < tzheadsize + datablock_size)
return EINVAL;
if (skip_datablock)
p += datablock_size;
else {
if (! ((ttisstdcnt == typecnt || ttisstdcnt == 0)
&& (ttisutcnt == typecnt || ttisutcnt == 0)))
return EINVAL;
sp->leapcnt = leapcnt;
sp->timecnt = timecnt;
sp->typecnt = typecnt;
sp->charcnt = charcnt;
/* Read transitions, discarding those out of time_t range.
But pretend the last transition before TIME_T_MIN
occurred at TIME_T_MIN. */
timecnt = 0;
for (i = 0; i < sp->timecnt; ++i) {
int_fast64_t at
= stored == 4 ? detzcode(p) : detzcode64(p);
sp->types[i] = at <= TIME_T_MAX;
if (sp->types[i]) {
time_t attime
= ((TYPE_SIGNED(time_t) ? at < TIME_T_MIN : at < 0)
? TIME_T_MIN : at);
if (timecnt && attime <= sp->ats[timecnt - 1]) {
if (attime < sp->ats[timecnt - 1])
return EINVAL;
sp->types[i - 1] = 0;
timecnt--;
}
sp->ats[timecnt++] = attime;
}
p += stored;
}
timecnt = 0;
for (i = 0; i < sp->timecnt; ++i) {
unsigned char typ = *p++;
if (sp->typecnt <= typ)
return EINVAL;
if (sp->types[i])
sp->types[timecnt++] = typ;
}
sp->timecnt = timecnt;
for (i = 0; i < sp->typecnt; ++i) {
register struct ttinfo * ttisp;
unsigned char isdst, desigidx;
ttisp = &sp->ttis[i];
ttisp->tt_utoff = detzcode(p);
p += 4;
isdst = *p++;
if (! (isdst < 2))
return EINVAL;
ttisp->tt_isdst = isdst;
desigidx = *p++;
if (! (desigidx < sp->charcnt))
return EINVAL;
ttisp->tt_desigidx = desigidx;
}
for (i = 0; i < sp->charcnt; ++i)
sp->chars[i] = *p++;
/* Ensure '\0'-terminated, and make it safe to call
ttunspecified later. */
memset(&sp->chars[i], 0, CHARS_EXTRA);
/* Read leap seconds, discarding those out of time_t range. */
leapcnt = 0;
for (i = 0; i < sp->leapcnt; ++i) {
int_fast64_t tr = stored == 4 ? detzcode(p) : detzcode64(p);
int_fast32_t corr = detzcode(p + stored);
p += stored + 4;
/* Leap seconds cannot occur before the Epoch,
or out of order. */
if (tr <= prevtr)
return EINVAL;
/* To avoid other botches in this code, each leap second's
correction must differ from the previous one's by 1
second or less, except that the first correction can be
any value; these requirements are more generous than
RFC 8536, to allow future RFC extensions. */
if (! (i == 0
|| (prevcorr < corr
? corr == prevcorr + 1
: (corr == prevcorr
|| corr == prevcorr - 1))))
return EINVAL;
prevtr = tr;
prevcorr = corr;
if (tr <= TIME_T_MAX) {
sp->lsis[leapcnt].ls_trans = tr;
sp->lsis[leapcnt].ls_corr = corr;
leapcnt++;
}
}
sp->leapcnt = leapcnt;
for (i = 0; i < sp->typecnt; ++i) {
register struct ttinfo * ttisp;
ttisp = &sp->ttis[i];
if (ttisstdcnt == 0)
ttisp->tt_ttisstd = false;
else {
if (*p != true && *p != false)
return EINVAL;
ttisp->tt_ttisstd = *p++;
}
}
for (i = 0; i < sp->typecnt; ++i) {
register struct ttinfo * ttisp;
ttisp = &sp->ttis[i];
if (ttisutcnt == 0)
ttisp->tt_ttisut = false;
else {
if (*p != true && *p != false)
return EINVAL;
ttisp->tt_ttisut = *p++;
}
}
}
nread -= p - up->buf;
memmove(up->buf, p, nread);
/* If this is an old file, we're done. */
if (!version)
break;
}
if (doextend && nread > 2 &&
up->buf[0] == '\n' && up->buf[nread - 1] == '\n' &&
sp->typecnt + 2 <= TZ_MAX_TYPES) {
struct state *ts = &lsp->u.st;
up->buf[nread - 1] = '\0';
if (tzparse(&up->buf[1], ts, sp)) {
/* Attempt to reuse existing abbreviations.
Without this, America/Anchorage would be right on
the edge after 2037 when TZ_MAX_CHARS is 50, as
sp->charcnt equals 40 (for LMT AST AWT APT AHST
AHDT YST AKDT AKST) and ts->charcnt equals 10
(for AKST AKDT). Reusing means sp->charcnt can
stay 40 in this example. */
int gotabbr = 0;
int charcnt = sp->charcnt;
for (i = 0; i < ts->typecnt; i++) {
char *tsabbr = ts->chars + ts->ttis[i].tt_desigidx;
int j;
for (j = 0; j < charcnt; j++)
if (strcmp(sp->chars + j, tsabbr) == 0) {
ts->ttis[i].tt_desigidx = j;
gotabbr++;
break;
}
if (! (j < charcnt)) {
int tsabbrlen = strlen(tsabbr);
if (j + tsabbrlen < TZ_MAX_CHARS) {
strcpy(sp->chars + j, tsabbr);
charcnt = j + tsabbrlen + 1;
ts->ttis[i].tt_desigidx = j;
gotabbr++;
}
}
}
if (gotabbr == ts->typecnt) {
sp->charcnt = charcnt;
/* Ignore any trailing, no-op transitions generated
by zic as they don't help here and can run afoul
of bugs in zic 2016j or earlier. */
while (1 < sp->timecnt
&& (sp->types[sp->timecnt - 1]
== sp->types[sp->timecnt - 2]))
sp->timecnt--;
for (i = 0;
i < ts->timecnt && sp->timecnt < TZ_MAX_TIMES;
i++) {
time_t t = ts->ats[i];
if (increment_overflow_time(&t, leapcorr(sp, t))
|| (0 < sp->timecnt
&& t <= sp->ats[sp->timecnt - 1]))
continue;
sp->ats[sp->timecnt] = t;
sp->types[sp->timecnt] = (sp->typecnt
+ ts->types[i]);
sp->timecnt++;
}
for (i = 0; i < ts->typecnt; i++)
sp->ttis[sp->typecnt++] = ts->ttis[i];
}
}
}
if (sp->typecnt == 0)
return EINVAL;
if (sp->timecnt > 1) {
if (sp->ats[0] <= TIME_T_MAX - SECSPERREPEAT) {
time_t repeatat = sp->ats[0] + SECSPERREPEAT;
int repeattype = sp->types[0];
for (i = 1; i < sp->timecnt; ++i)
if (sp->ats[i] == repeatat
&& typesequiv(sp, sp->types[i], repeattype)) {
sp->goback = true;
break;
}
}
if (TIME_T_MIN + SECSPERREPEAT <= sp->ats[sp->timecnt - 1]) {
time_t repeatat = sp->ats[sp->timecnt - 1] - SECSPERREPEAT;
int repeattype = sp->types[sp->timecnt - 1];
for (i = sp->timecnt - 2; i >= 0; --i)
if (sp->ats[i] == repeatat
&& typesequiv(sp, sp->types[i], repeattype)) {
sp->goahead = true;
break;
}
}
}
/* Infer sp->defaulttype from the data. Although this default
type is always zero for data from recent tzdb releases,
things are trickier for data from tzdb 2018e or earlier.
The first set of heuristics work around bugs in 32-bit data
generated by tzdb 2013c or earlier. The workaround is for
zones like Australia/Macquarie where timestamps before the
first transition have a time type that is not the earliest
standard-time type. See:
https://mm.icann.org/pipermail/tz/2013-May/019368.html */
/*
** If type 0 does not specify local time, or is unused in transitions,
** it's the type to use for early times.
*/
for (i = 0; i < sp->timecnt; ++i)
if (sp->types[i] == 0)
break;
i = i < sp->timecnt && ! ttunspecified(sp, 0) ? -1 : 0;
/*
** Absent the above,
** if there are transition times
** and the first transition is to a daylight time
** find the standard type less than and closest to
** the type of the first transition.
*/
if (i < 0 && sp->timecnt > 0 && sp->ttis[sp->types[0]].tt_isdst) {
i = sp->types[0];
while (--i >= 0)
if (!sp->ttis[i].tt_isdst)
break;
}
/* The next heuristics are for data generated by tzdb 2018e or
earlier, for zones like EST5EDT where the first transition
is to DST. */
/*
** If no result yet, find the first standard type.
** If there is none, punt to type zero.
*/
if (i < 0) {
i = 0;
while (sp->ttis[i].tt_isdst)
if (++i >= sp->typecnt) {
i = 0;
break;
}
}
/* A simple 'sp->defaulttype = 0;' would suffice here if we
didn't have to worry about 2018e-or-earlier data. Even
simpler would be to remove the defaulttype member and just
use 0 in its place. */
sp->defaulttype = i;
return 0;
}
/* Load tz data from the file named NAME into *SP. Read extended
format if DOEXTEND. Return 0 on success, an errno value on failure. */
static int
tzload(char const *name, struct state *sp, bool doextend)
{
#ifdef ALL_STATE
union local_storage *lsp = malloc(sizeof *lsp);
if (!lsp) {
return HAVE_MALLOC_ERRNO ? errno : ENOMEM;
} else {
int err = tzloadbody(name, sp, doextend, lsp);
free(lsp);
return err;
}
#else
union local_storage ls;
return tzloadbody(name, sp, doextend, &ls);
#endif
}
static bool
typesequiv(const struct state *sp, int a, int b)
{
register bool result;
if (sp == NULL ||
a < 0 || a >= sp->typecnt ||
b < 0 || b >= sp->typecnt)
result = false;
else {
/* Compare the relevant members of *AP and *BP.
Ignore tt_ttisstd and tt_ttisut, as they are
irrelevant now and counting them could cause
sp->goahead to mistakenly remain false. */
register const struct ttinfo * ap = &sp->ttis[a];
register const struct ttinfo * bp = &sp->ttis[b];
result = (ap->tt_utoff == bp->tt_utoff
&& ap->tt_isdst == bp->tt_isdst
&& (strcmp(&sp->chars[ap->tt_desigidx],
&sp->chars[bp->tt_desigidx])
== 0));
}
return result;
}
static const int mon_lengths[2][MONSPERYEAR] = {
{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
{ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
};
static const int year_lengths[2] = {
DAYSPERNYEAR, DAYSPERLYEAR
};
/* Is C an ASCII digit? */
static bool
is_digit(char c)
{
return '0' <= c && c <= '9';
}
/*
** Given a pointer into a timezone string, scan until a character that is not
** a valid character in a time zone abbreviation is found.
** Return a pointer to that character.
*/
ATTRIBUTE_REPRODUCIBLE static const char *
getzname(register const char *strp)
{
register char c;
while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' &&
c != '+')
++strp;
return strp;
}
/*
** Given a pointer into an extended timezone string, scan until the ending
** delimiter of the time zone abbreviation is located.
** Return a pointer to the delimiter.
**
** As with getzname above, the legal character set is actually quite
** restricted, with other characters producing undefined results.
** We don't do any checking here; checking is done later in common-case code.
*/
ATTRIBUTE_REPRODUCIBLE static const char *
getqzname(register const char *strp, const int delim)
{
register int c;
while ((c = *strp) != '\0' && c != delim)
++strp;
return strp;
}
/*
** Given a pointer into a timezone string, extract a number from that string.
** Check that the number is within a specified range; if it is not, return
** NULL.
** Otherwise, return a pointer to the first character not part of the number.
*/
static const char *
getnum(register const char *strp, int *const nump, const int min, const int max)
{
register char c;
register int num;
if (strp == NULL || !is_digit(c = *strp))
return NULL;
num = 0;
do {
num = num * 10 + (c - '0');
if (num > max)
return NULL; /* illegal value */
c = *++strp;
} while (is_digit(c));
if (num < min)
return NULL; /* illegal value */
*nump = num;
return strp;
}
/*
** Given a pointer into a timezone string, extract a number of seconds,
** in hh[:mm[:ss]] form, from the string.
** If any error occurs, return NULL.
** Otherwise, return a pointer to the first character not part of the number
** of seconds.
*/
static const char *
getsecs(register const char *strp, int_fast32_t *const secsp)
{
int num;
int_fast32_t secsperhour = SECSPERHOUR;
/*
** 'HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
** "M10.4.6/26", which does not conform to Posix,
** but which specifies the equivalent of
** "02:00 on the first Sunday on or after 23 Oct".
*/
strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
if (strp == NULL)
return NULL;
*secsp = num * secsperhour;
if (*strp == ':') {
++strp;
strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
if (strp == NULL)
return NULL;
*secsp += num * SECSPERMIN;
if (*strp == ':') {
++strp;
/* 'SECSPERMIN' allows for leap seconds. */
strp = getnum(strp, &num, 0, SECSPERMIN);
if (strp == NULL)
return NULL;
*secsp += num;
}
}
return strp;
}
/*
** Given a pointer into a timezone string, extract an offset, in
** [+-]hh[:mm[:ss]] form, from the string.
** If any error occurs, return NULL.
** Otherwise, return a pointer to the first character not part of the time.
*/
static const char *
getoffset(register const char *strp, int_fast32_t *const offsetp)
{
register bool neg = false;
if (*strp == '-') {
neg = true;
++strp;
} else if (*strp == '+')
++strp;
strp = getsecs(strp, offsetp);
if (strp == NULL)
return NULL; /* illegal time */
if (neg)
*offsetp = -*offsetp;
return strp;
}
/*
** Given a pointer into a timezone string, extract a rule in the form
** date[/time]. See POSIX section 8 for the format of "date" and "time".
** If a valid rule is not found, return NULL.