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];
18 const char __gmt[] = "GMT";
21 static int r0[5], r1[5];
23 static const unsigned char *zi, *trans, *index, *types, *abbrevs, *abbrevs_end;
24 static size_t map_size;
26 static char old_tz_buf[32];
27 static char *old_tz = old_tz_buf;
28 static size_t old_tz_size = sizeof old_tz_buf;
32 static int getint(const char **p)
35 for (x=0; **p-'0'<10U; (*p)++) x = **p-'0' + 10*x;
39 static int getsigned(const char **p)
49 static int getoff(const char **p)
51 int off = 3600*getsigned(p);
63 static void getrule(const char **p, int rule[5])
65 int r = rule[0] = **p;
72 ++*p; rule[1] = getint(p);
73 ++*p; rule[2] = getint(p);
74 ++*p; rule[3] = getint(p);
85 static void getname(char *d, const char **p)
90 for (i=0; **p!='>' && i<TZNAME_MAX; i++)
94 for (i=0; ((*p)[i]|32)-'a'<26U && i<TZNAME_MAX; i++)
101 #define VEC(...) ((const unsigned char[]){__VA_ARGS__})
103 static uint32_t zi_read32(const unsigned char *z)
105 return (unsigned)z[0]<<24 | z[1]<<16 | z[2]<<8 | z[3];
108 static size_t zi_dotprod(const unsigned char *z, const unsigned char *v, size_t n)
112 for (y=0; n; n--, z+=4, v++) {
119 int __munmap(void *, size_t);
121 static void do_tzset()
123 char buf[NAME_MAX+25], *pathname=buf+24;
124 const char *try, *s, *p;
125 const unsigned char *map = 0;
127 static const char search[] =
128 "/usr/share/zoneinfo/\0/share/zoneinfo/\0/etc/zoneinfo/\0";
131 if (!s || !*s) s = "/etc/localtime";
133 if (old_tz && !strcmp(s, old_tz)) return;
135 if (zi) __munmap((void *)zi, map_size);
137 /* Cache the old value of TZ to check if it has changed. Avoid
138 * free so as not to pull it into static programs. Growth
139 * strategy makes it so free would have minimal benefit anyway. */
141 if (i > PATH_MAX+1) s = __gmt, i = 3;
142 if (i >= old_tz_size) {
144 if (i >= old_tz_size) old_tz_size = i+1;
145 if (old_tz_size > PATH_MAX+2) old_tz_size = PATH_MAX+2;
146 old_tz = malloc(old_tz_size);
148 if (old_tz) memcpy(old_tz, s, i+1);
150 /* Non-suid can use an absolute tzfile pathname or a relative
151 * pathame beginning with "."; in secure mode, only the
152 * standard path will be searched. */
153 if (*s == ':' || ((p=strchr(s, '/')) && !memchr(s, ',', p-s))) {
155 if (*s == '/' || *s == '.') {
156 if (!libc.secure || !strcmp(s, "/etc/localtime"))
157 map = __map_file(s, &map_size);
159 size_t l = strlen(s);
160 if (l <= NAME_MAX && !strchr(s, '.')) {
161 memcpy(pathname, s, l+1);
163 for (try=search; !map && *try; try+=l+1) {
165 memcpy(pathname-l, try, l);
166 map = __map_file(pathname-l, &map_size);
172 if (map && (map_size < 44 || memcmp(map, "TZif", 4))) {
173 __munmap((void *)map, map_size);
181 if (sizeof(time_t) > 4 && map[4]=='2') {
182 size_t skip = zi_dotprod(zi+20, VEC(1,1,8,5,6,1), 6);
183 trans = zi+skip+44+44;
188 index = trans + (zi_read32(trans-12) << scale);
189 types = index + zi_read32(trans-12);
190 abbrevs = types + 6*zi_read32(trans-8);
191 abbrevs_end = abbrevs + zi_read32(trans-4);
192 if (zi[map_size-1] == '\n') {
193 for (s = (const char *)zi+map_size-2; *s!='\n'; s--);
196 const unsigned char *p;
197 __tzname[0] = __tzname[1] = 0;
198 __daylight = __timezone = dst_off = 0;
199 for (i=0; i<5; i++) r0[i] = r1[i] = 0;
200 for (p=types; p<abbrevs; p+=6) {
201 if (!p[4] && !__tzname[0]) {
202 __tzname[0] = (char *)abbrevs + p[5];
203 __timezone = -zi_read32(p);
205 if (p[4] && !__tzname[1]) {
206 __tzname[1] = (char *)abbrevs + p[5];
207 dst_off = -zi_read32(p);
211 if (!__tzname[0]) __tzname[0] = __tzname[1];
212 if (!__tzname[0]) __tzname[0] = (char *)__gmt;
214 __tzname[1] = __tzname[0];
215 dst_off = __timezone;
222 getname(std_name, &s);
223 __tzname[0] = std_name;
224 __timezone = getoff(&s);
225 getname(dst_name, &s);
226 __tzname[1] = dst_name;
229 if (*s == '+' || *s=='-' || *s-'0'<10U)
230 dst_off = getoff(&s);
232 dst_off = __timezone - 3600;
238 if (*s == ',') s++, getrule(&s, r0);
239 if (*s == ',') s++, getrule(&s, r1);
242 /* Search zoneinfo rules to find the one that applies to the given time,
243 * and determine alternate opposite-DST-status rule that may be needed. */
245 static size_t scan_trans(long long t, int local, size_t *alt)
247 int scale = 3 - (trans == zi+44);
251 size_t a = 0, n = (index-trans)>>scale, m;
258 /* Binary search for 'most-recent rule before t'. */
261 x = zi_read32(trans + (m<<scale));
262 if (scale == 3) x = x<<32 | zi_read32(trans + (m<<scale) + 4);
264 if (local) off = (int32_t)zi_read32(types + 6 * index[m-1]);
265 if (t - off < (int64_t)x) {
273 /* First and last entry are special. First means to use lowest-index
274 * non-DST type. Last means to apply POSIX-style rule if available. */
275 n = (index-trans)>>scale;
276 if (a == n-1) return -1;
278 x = zi_read32(trans + (a<<scale));
279 if (scale == 3) x = x<<32 | zi_read32(trans + (a<<scale) + 4);
281 if (local) off = (int32_t)zi_read32(types + 6 * index[a-1]);
282 if (t - off < (int64_t)x) {
283 for (a=0; a<(abbrevs-types)/6; a++) {
284 if (types[6*a+4] != types[4]) break;
286 if (a == (abbrevs-types)/6) a = 0;
297 /* Try to find a neighboring opposite-DST-status rule. */
299 if (a && types[6*index[a-1]+4] != types[6*index[a]+4])
301 else if (a+1<n && types[6*index[a+1]+4] != types[6*index[a]+4])
310 static int days_in_month(int m, int is_leap)
312 if (m==2) return 28+is_leap;
313 else return 30+((0xad5>>(m-1))&1);
316 /* Convert a POSIX DST rule plus year to seconds since epoch. */
318 static long long rule_to_secs(const int *rule, int year)
321 long long t = __year_to_secs(year, &is_leap);
325 if (rule[0]=='J' && (x < 60 || !is_leap)) x--;
331 t += __month_to_secs(m-1, is_leap);
332 int wday = (int)((t + 4*86400) % (7*86400)) / 86400;
334 if (days < 0) days += 7;
335 if (n == 5 && days+28 >= days_in_month(m, is_leap)) n = 4;
336 t += 86400 * (days + 7*(n-1));
342 /* Determine the time zone in effect for a given time in seconds since the
343 * epoch. It can be given in local or universal time. The results will
344 * indicate whether DST is in effect at the queried time, and will give both
345 * the GMT offset for the active zone/DST rule and the opposite DST. This
346 * enables a caller to efficiently adjust for the case where an explicit
347 * DST specification mismatches what would be in effect at the time. */
349 void __secs_to_zone(long long t, int local, int *isdst, long *offset, long *oppoff, const char **zonename)
356 size_t alt, i = scan_trans(t, local, &alt);
358 *isdst = types[6*i+4];
359 *offset = -(int32_t)zi_read32(types+6*i);
360 *zonename = (const char *)abbrevs + types[6*i+5];
361 if (oppoff) *oppoff = -(int32_t)zi_read32(types+6*alt);
367 if (!__daylight) goto std;
369 /* FIXME: may be broken if DST changes right at year boundary?
370 * Also, this could be more efficient.*/
371 long long y = t / 31556952 + 70;
372 while (__year_to_secs(y, 0) > t) y--;
373 while (__year_to_secs(y+1, 0) < t) y++;
375 long long t0 = rule_to_secs(r0, y);
376 long long t1 = rule_to_secs(r1, y);
383 if (t >= t0 && t < t1) goto dst;
390 if (t >= t1 && t < t0) goto std;
395 *offset = __timezone;
396 if (oppoff) *oppoff = dst_off;
397 *zonename = __tzname[0];
403 if (oppoff) *oppoff = __timezone;
404 *zonename = __tzname[1];
415 weak_alias(__tzset, tzset);
417 const char *__tm_to_tzname(const struct tm *tm)
419 const void *p = tm->__tm_zone;
422 if (p != __gmt && p != __tzname[0] && p != __tzname[1] &&
423 (!zi || (uintptr_t)p-(uintptr_t)abbrevs >= abbrevs_end - abbrevs))