10 char *__tzname[2] = { 0, 0 };
12 weak_alias(__timezone, timezone);
13 weak_alias(__daylight, daylight);
14 weak_alias(__tzname, tzname);
16 static char std_name[TZNAME_MAX+1];
17 static char dst_name[TZNAME_MAX+1];
20 static int r0[5], r1[5];
22 static const unsigned char *zi, *trans, *index, *types, *abbrevs;
23 static size_t map_size;
25 static char old_tz_buf[32];
26 static char *old_tz = old_tz_buf;
27 static size_t old_tz_size = sizeof old_tz_buf;
31 static int getint(const char **p)
34 for (x=0; **p-'0'<10U; (*p)++) x = **p-'0' + 10*x;
38 static int getsigned(const char **p)
48 static int getoff(const char **p)
50 int off = 3600*getsigned(p);
62 static void getrule(const char **p, int rule[5])
64 int r = rule[0] = **p;
71 ++*p; rule[1] = getint(p);
72 ++*p; rule[2] = getint(p);
73 ++*p; rule[3] = getint(p);
84 static void getname(char *d, const char **p)
89 for (i=0; **p!='>' && i<TZNAME_MAX; i++)
93 for (i=0; ((*p)[i]|32)-'a'<26U && i<TZNAME_MAX; i++)
100 #define VEC(...) ((const unsigned char[]){__VA_ARGS__})
102 static uint32_t zi_read32(const unsigned char *z)
104 return (unsigned)z[0]<<24 | z[1]<<16 | z[2]<<8 | z[3];
107 static size_t zi_dotprod(const unsigned char *z, const unsigned char *v, size_t n)
111 for (y=0; n; n--, z+=4, v++) {
118 int __munmap(void *, size_t);
120 static void do_tzset()
122 char buf[NAME_MAX+25], *pathname=buf+24;
124 const unsigned char *map = 0;
126 static const char search[] =
127 "/usr/share/zoneinfo/\0/share/zoneinfo/\0/etc/zoneinfo/\0";
130 if (!s || !*s) s = "GMT0";
132 if (old_tz && !strcmp(s, old_tz)) return;
134 if (zi) __munmap((void *)zi, map_size);
136 /* Cache the old value of TZ to check if it has changed. Avoid
137 * free so as not to pull it into static programs. Growth
138 * strategy makes it so free would have minimal benefit anyway. */
140 if (i > PATH_MAX+1) s = "", i = 0;
141 if (i >= old_tz_size) {
143 if (i >= old_tz_size) old_tz_size = i+1;
144 if (old_tz_size > PATH_MAX+2) old_tz_size = PATH_MAX+2;
145 old_tz = malloc(old_tz_size);
147 if (old_tz) memcpy(old_tz, s, i+1);
151 /* Non-suid can use an absolute tzfile pathname or a relative
152 * pathame beginning with "."; in secure mode, only the
153 * standard path will be searched. */
154 if (*s == '/' || *s == '.') {
155 if (!libc.secure) map = __map_file(s, &map_size);
157 for (i=0; s[i] && s[i]!=','; i++) {
159 size_t l = strlen(s);
160 if (l > NAME_MAX || strchr(s, '.'))
162 memcpy(pathname, s, l+1);
164 for (try=search; !map && *try; try+=l) {
166 memcpy(pathname-l, try, l);
167 map = __map_file(pathname-l, &map_size);
177 if (sizeof(time_t) > 4 && map[4]=='2') {
178 size_t skip = zi_dotprod(zi, VEC(1,1,8,5,6,1), 6);
179 trans = zi+skip+44+20;
184 index = trans + (zi_read32(trans-12) << scale);
185 types = index + zi_read32(trans-12);
186 abbrevs = types + 6*zi_read32(trans-8);
187 if (zi[map_size-1] == '\n') {
188 for (s = (const char *)zi+map_size-2; *s!='\n'; s--);
196 getname(std_name, &s);
197 __tzname[0] = std_name;
198 __timezone = getoff(&s);
199 getname(dst_name, &s);
200 __tzname[1] = dst_name;
203 if (*s == '+' || *s=='-' || *s-'0'<10U)
204 dst_off = getoff(&s);
206 dst_off = __timezone - 3600;
212 if (*s == ',') s++, getrule(&s, r0);
213 if (*s == ',') s++, getrule(&s, r1);
216 /* Search zoneinfo rules to find the one that applies to the given time,
217 * and determine alternate opposite-DST-status rule that may be needed. */
219 static size_t scan_trans(long long t, int local, size_t *alt)
221 int scale = 3 - (trans == zi+44);
225 size_t a = 0, n = (index-trans)>>scale, m;
232 /* Binary search for 'most-recent rule before t'. */
235 x = zi_read32(trans + (m<<scale));
236 if (scale == 3) x = x<<32 | zi_read32(trans + (m<<scale) + 4);
238 if (local) off = (int32_t)zi_read32(types + 6 * index[m-1]);
239 if (t - off < (int64_t)x) {
247 /* First and last entry are special. First means to use lowest-index
248 * non-DST type. Last means to apply POSIX-style rule if available. */
249 n = (index-trans)>>scale;
250 if (a == n-1) return -1;
252 x = zi_read32(trans + (a<<scale));
253 if (scale == 3) x = x<<32 | zi_read32(trans + (a<<scale) + 4);
255 if (local) off = (int32_t)zi_read32(types + 6 * index[a-1]);
256 if (t - off < (int64_t)x) {
257 for (a=0; a<(abbrevs-types)/6; a++) {
258 if (types[6*a+4] != types[4]) break;
260 if (a == (abbrevs-types)/6) a = 0;
271 /* Try to find a neighboring opposite-DST-status rule. */
273 if (a && types[6*index[a-1]+4] != types[6*index[a]+4])
275 else if (a+1<n && types[6*index[a+1]+4] != types[6*index[a]+4])
284 static int days_in_month(int m, int is_leap)
286 if (m==2) return 28+is_leap;
287 else return 30+((0xad5>>(m-1))&1);
290 /* Convert a POSIX DST rule plus year to seconds since epoch. */
292 static long long rule_to_secs(const int *rule, int year)
295 long long t = __year_to_secs(year, &is_leap);
299 if (rule[0]=='J' && (x < 60 || !is_leap)) x--;
305 t += __month_to_secs(m-1, is_leap);
306 int wday = (int)((t + 4*86400) % (7*86400)) / 86400;
308 if (days < 0) days += 7;
309 if (n == 5 && days+28 >= days_in_month(m, is_leap)) n = 4;
310 t += 86400 * (days + 7*(n-1));
316 /* Determine the time zone in effect for a given time in seconds since the
317 * epoch. It can be given in local or universal time. The results will
318 * indicate whether DST is in effect at the queried time, and will give both
319 * the GMT offset for the active zone/DST rule and the opposite DST. This
320 * enables a caller to efficiently adjust for the case where an explicit
321 * DST specification mismatches what would be in effect at the time. */
323 void __secs_to_zone(long long t, int local, int *isdst, long *offset, long *oppoff, const char **zonename)
330 size_t alt, i = scan_trans(t, local, &alt);
332 *isdst = types[6*i+4];
333 *offset = -(int32_t)zi_read32(types+6*i);
334 *zonename = (const char *)abbrevs + types[6*i+5];
335 if (oppoff) *oppoff = -(int32_t)zi_read32(types+6*alt);
341 if (!__daylight) goto std;
343 /* FIXME: may be broken if DST changes right at year boundary?
344 * Also, this could be more efficient.*/
345 long long y = t / 31556952 + 70;
346 while (__year_to_secs(y, 0) > t) y--;
347 while (__year_to_secs(y+1, 0) < t) y++;
349 long long t0 = rule_to_secs(r0, y);
350 long long t1 = rule_to_secs(r1, y);
357 if (t >= t0 && t < t1) goto dst;
364 if (t >= t1 && t < t0) goto std;
369 *offset = __timezone;
370 if (oppoff) *oppoff = dst_off;
371 *zonename = __tzname[0];
377 if (oppoff) *oppoff = __timezone;
378 *zonename = __tzname[1];
389 weak_alias(__tzset, tzset);