#include "time_impl.h"
#include <stdint.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include "libc.h"
long __timezone = 0;
int __daylight = 0;
char *__tzname[2] = { 0, 0 };
weak_alias(__timezone, timezone);
weak_alias(__daylight, daylight);
weak_alias(__tzname, tzname);
static char std_name[TZNAME_MAX+1];
static char dst_name[TZNAME_MAX+1];
const char __gmt[] = "GMT";
static int dst_off;
static int r0[5], r1[5];
static const unsigned char *zi, *trans, *index, *types, *abbrevs, *abbrevs_end;
static size_t map_size;
static char old_tz_buf[32];
static char *old_tz = old_tz_buf;
static size_t old_tz_size = sizeof old_tz_buf;
static int lock[2];
static int getint(const char **p)
{
unsigned x;
for (x=0; **p-'0'<10U; (*p)++) x = **p-'0' + 10*x;
return x;
}
static int getsigned(const char **p)
{
if (**p == '-') {
++*p;
return -getint(p);
}
if (**p == '+') ++*p;
return getint(p);
}
static int getoff(const char **p)
{
int off = 3600*getsigned(p);
if (**p == ':') {
++*p;
off += 60*getint(p);
if (**p == ':') {
++*p;
off += getint(p);
}
}
return off;
}
static void getrule(const char **p, int rule[5])
{
int r = rule[0] = **p;
if (r!='M') {
if (r=='J') ++*p;
else rule[0] = 0;
rule[1] = getint(p);
} else {
++*p; rule[1] = getint(p);
++*p; rule[2] = getint(p);
++*p; rule[3] = getint(p);
}
if (**p=='/') {
++*p;
rule[4] = getoff(p);
} else {
rule[4] = 7200;
}
}
static void getname(char *d, const char **p)
{
int i;
if (**p == '<') {
++*p;
for (i=0; **p!='>' && i<TZNAME_MAX; i++)
d[i] = (*p)[i];
++*p;
} else {
for (i=0; ((*p)[i]|32)-'a'<26U && i<TZNAME_MAX; i++)
d[i] = (*p)[i];
}
*p += i;
d[i] = 0;
}
#define VEC(...) ((const unsigned char[]){__VA_ARGS__})
static uint32_t zi_read32(const unsigned char *z)
{
return (unsigned)z[0]<<24 | z[1]<<16 | z[2]<<8 | z[3];
}
static size_t zi_dotprod(const unsigned char *z, const unsigned char *v, size_t n)
{
size_t y;
uint32_t x;
for (y=0; n; n--, z+=4, v++) {
x = zi_read32(z);
y += x * *v;
}
return y;
}
int __munmap(void *, size_t);
static void do_tzset()
{
char buf[NAME_MAX+25], *pathname=buf+24;
const char *try, *s, *p;
const unsigned char *map = 0;
size_t i;
static const char search[] =
"/usr/share/zoneinfo/\0/share/zoneinfo/\0/etc/zoneinfo/\0";
s = getenv("TZ");
if (!s || !*s) s = __gmt;
if (old_tz && !strcmp(s, old_tz)) return;
if (zi) __munmap((void *)zi, map_size);
/* Cache the old value of TZ to check if it has changed. Avoid
* free so as not to pull it into static programs. Growth
* strategy makes it so free would have minimal benefit anyway. */
i = strlen(s);
if (i > PATH_MAX+1) s = __gmt, i = 3;
if (i >= old_tz_size) {
old_tz_size *= 2;
if (i >= old_tz_size) old_tz_size = i+1;
if (old_tz_size > PATH_MAX+2) old_tz_size = PATH_MAX+2;
old_tz = malloc(old_tz_size);
}
if (old_tz) memcpy(old_tz, s, i+1);
/* Non-suid can use an absolute tzfile pathname or a relative
* pathame beginning with "."; in secure mode, only the
* standard path will be searched. */
if (*s == ':' || ((p=strchr(s, '/')) && !memchr(s, ',', p-s))) {
if (*s == ':') s++;
if (*s == '/' || *s == '.') {
if (!libc.secure) map = __map_file(s, &map_size);
} else {
size_t l = strlen(s);
if (l <= NAME_MAX && !strchr(s, '.')) {
memcpy(pathname, s, l+1);
pathname[l] = 0;
for (try=search; !map && *try; try+=l+1) {
l = strlen(try);
memcpy(pathname-l, try, l);
map = __map_file(pathname-l, &map_size);
}
}
}
if (!map) s = __gmt;
}
if (map && (map_size < 44 || memcmp(map, "TZif", 4))) {
__munmap((void *)map, map_size);
map = 0;
s = __gmt;
}
zi = map;
if (map) {
int scale = 2;
if (sizeof(time_t) > 4 && map[4]=='2') {
size_t skip = zi_dotprod(zi+20, VEC(1,1,8,5,6,1), 6);
trans = zi+skip+44+44;
scale++;
} else {
trans = zi+44;
}
index = trans + (zi_read32(trans-12) << scale);
types = index + zi_read32(trans-12);
abbrevs = types + 6*zi_read32(trans-8);
abbrevs_end = abbrevs + zi_read32(trans-4);
if (zi[map_size-1] == '\n') {
for (s = (const char *)zi+map_size-2; *s!='\n'; s--);
s++;
} else {
const unsigned char *p;
__tzname[0] = __tzname[1] = 0;
__daylight = __timezone = dst_off = 0;
for (i=0; i<5; i++) r0[i] = r1[i] = 0;
for (p=types; p<abbrevs; p+=6) {
if (!p[4] && !__tzname[0]) {
__tzname[0] = (char *)abbrevs + p[5];
__timezone = -zi_read32(p);
}
if (p[4] && !__tzname[1]) {
__tzname[1] = (char *)abbrevs + p[5];
dst_off = -zi_read32(p);
__daylight = 1;
}
}
if (!__tzname[0]) __tzname[0] = __tzname[1];
if (!__tzname[0]) __tzname[0] = (char *)__gmt;
if (!__daylight) {
__tzname[1] = __tzname[0];
dst_off = __timezone;
}
return;
}
}
if (!s) s = __gmt;
getname(std_name, &s);
__tzname[0] = std_name;
__timezone = getoff(&s);
getname(dst_name, &s);
__tzname[1] = dst_name;
if (dst_name[0]) {
__daylight = 1;
if (*s == '+' || *s=='-' || *s-'0'<10U)
dst_off = getoff(&s);
else
dst_off = __timezone - 3600;
} else {
__daylight = 0;
dst_off = 0;
}
if (*s == ',') s++, getrule(&s, r0);
if (*s == ',') s++, getrule(&s, r1);
}
/* Search zoneinfo rules to find the one that applies to the given time,
* and determine alternate opposite-DST-status rule that may be needed. */
static size_t scan_trans(long long t, int local, size_t *alt)
{
int scale = 3 - (trans == zi+44);
uint64_t x;
int off = 0;
size_t a = 0, n = (index-trans)>>scale, m;
if (!n) {
if (alt) *alt = 0;
return 0;
}
/* Binary search for 'most-recent rule before t'. */
while (n > 1) {
m = a + n/2;
x = zi_read32(trans + (m<<scale));
if (scale == 3) x = x<<32 | zi_read32(trans + (m<<scale) + 4);
else x = (int32_t)x;
if (local) off = (int32_t)zi_read32(types + 6 * index[m-1]);
if (t - off < (int64_t)x) {
n /= 2;
} else {
a = m;
n -= n/2;
}
}
/* First and last entry are special. First means to use lowest-index
* non-DST type. Last means to apply POSIX-style rule if available. */
n = (index-trans)>>scale;
if (a == n-1) return -1;
if (a == 0) {
x = zi_read32(trans + (a<<scale));
if (scale == 3) x = x<<32 | zi_read32(trans + (a<<scale) + 4);
else x = (int32_t)x;
if (local) off = (int32_t)zi_read32(types + 6 * index[a-1]);
if (t - off < (int64_t)x) {
for (a=0; a<(abbrevs-types)/6; a++) {
if (types[6*a+4] != types[4]) break;
}
if (a == (abbrevs-types)/6) a = 0;
if (types[6*a+4]) {
*alt = a;
return 0;
} else {
*alt = 0;
return a;
}
}
}
/* Try to find a neighboring opposite-DST-status rule. */
if (alt) {
if (a && types[6*index[a-1]+4] != types[6*index[a]+4])
*alt = index[a-1];
else if (a+1<n && types[6*index[a+1]+4] != types[6*index[a]+4])
*alt = index[a+1];
else
*alt = index[a];
}
return index[a];
}
static int days_in_month(int m, int is_leap)
{
if (m==2) return 28+is_leap;
else return 30+((0xad5>>(m-1))&1);
}
/* Convert a POSIX DST rule plus year to seconds since epoch. */
static long long rule_to_secs(const int *rule, int year)
{
int is_leap;
long long t = __year_to_secs(year, &is_leap);
int x, m, n, d;
if (rule[0]!='M') {
x = rule[1];
if (rule[0]=='J' && (x < 60 || !is_leap)) x--;
t += 86400 * x;
} else {
m = rule[1];
n = rule[2];
d = rule[3];
t += __month_to_secs(m-1, is_leap);
int wday = (int)((t + 4*86400) % (7*86400)) / 86400;
int days = d - wday;
if (days < 0) days += 7;
if (n == 5 && days+28 >= days_in_month(m, is_leap)) n = 4;
t += 86400 * (days + 7*(n-1));
}
t += rule[4];
return t;
}
/* Determine the time zone in effect for a given time in seconds since the
* epoch. It can be given in local or universal time. The results will
* indicate whether DST is in effect at the queried time, and will give both
* the GMT offset for the active zone/DST rule and the opposite DST. This
* enables a caller to efficiently adjust for the case where an explicit
* DST specification mismatches what would be in effect at the time. */
void __secs_to_zone(long long t, int local, int *isdst, long *offset, long *oppoff, const char **zonename)
{
LOCK(lock);
do_tzset();
if (zi) {
size_t alt, i = scan_trans(t, local, &alt);
if (i != -1) {
*isdst = types[6*i+4];
*offset = -(int32_t)zi_read32(types+6*i);
*zonename = (const char *)abbrevs + types[6*i+5];
if (oppoff) *oppoff = -(int32_t)zi_read32(types+6*alt);
UNLOCK(lock);
return;
}
}
if (!__daylight) goto std;
/* FIXME: may be broken if DST changes right at year boundary?
* Also, this could be more efficient.*/
long long y = t / 31556952 + 70;
while (__year_to_secs(y, 0) > t) y--;
while (__year_to_secs(y+1, 0) < t) y++;
long long t0 = rule_to_secs(r0, y);
long long t1 = rule_to_secs(r1, y);
if (t0 < t1) {
if (!local) {
t0 += __timezone;
t1 += dst_off;
}
if (t >= t0 && t < t1) goto dst;
goto std;
} else {
if (!local) {
t1 += __timezone;
t0 += dst_off;
}
if (t >= t1 && t < t0) goto std;
goto dst;
}
std:
*isdst = 0;
*offset = __timezone;
if (oppoff) *oppoff = dst_off;
*zonename = __tzname[0];
UNLOCK(lock);
return;
dst:
*isdst = 1;
*offset = dst_off;
if (oppoff) *oppoff = __timezone;
*zonename = __tzname[1];
UNLOCK(lock);
}
void __tzset()
{
LOCK(lock);
do_tzset();
UNLOCK(lock);
}
weak_alias(__tzset, tzset);
const char *__tm_to_tzname(const struct tm *tm)
{
const void *p = tm->__tm_zone;
LOCK(lock);
do_tzset();
if (p != __gmt && p != __tzname[0] && p != __tzname[1] &&
(!zi || (uintptr_t)p-(uintptr_t)abbrevs >= abbrevs_end - abbrevs))
p = "";
UNLOCK(lock);
return p;
}
