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320054e8 DG |
1 | #include "time_impl.h" |
2 | #include <stdint.h> | |
3 | #include <limits.h> | |
4 | #include <stdlib.h> | |
5 | #include <string.h> | |
6 | #ifdef __wasilibc_unmodified_upstream // timezone data | |
7 | #include <sys/mman.h> | |
8 | #endif | |
9 | #include "libc.h" | |
10 | #include "lock.h" | |
11 | ||
12 | #ifdef __wasilibc_unmodified_upstream // timezone data | |
13 | long __timezone = 0; | |
14 | int __daylight = 0; | |
15 | char *__tzname[2] = { 0, 0 }; | |
16 | ||
17 | weak_alias(__timezone, timezone); | |
18 | weak_alias(__daylight, daylight); | |
19 | weak_alias(__tzname, tzname); | |
20 | ||
21 | static char std_name[TZNAME_MAX+1]; | |
22 | static char dst_name[TZNAME_MAX+1]; | |
23 | #endif | |
24 | const char __utc[] = "UTC"; | |
25 | ||
26 | #ifdef __wasilibc_unmodified_upstream // timezone data | |
27 | static int dst_off; | |
28 | static int r0[5], r1[5]; | |
29 | ||
30 | static const unsigned char *zi, *trans, *index, *types, *abbrevs, *abbrevs_end; | |
31 | static size_t map_size; | |
32 | ||
33 | static char old_tz_buf[32]; | |
34 | static char *old_tz = old_tz_buf; | |
35 | static size_t old_tz_size = sizeof old_tz_buf; | |
36 | ||
37 | static volatile int lock[1]; | |
38 | ||
39 | static int getint(const char **p) | |
40 | { | |
41 | unsigned x; | |
42 | for (x=0; **p-'0'<10U; (*p)++) x = **p-'0' + 10*x; | |
43 | return x; | |
44 | } | |
45 | ||
46 | static int getoff(const char **p) | |
47 | { | |
48 | int neg = 0; | |
49 | if (**p == '-') { | |
50 | ++*p; | |
51 | neg = 1; | |
52 | } else if (**p == '+') { | |
53 | ++*p; | |
54 | } | |
55 | int off = 3600*getint(p); | |
56 | if (**p == ':') { | |
57 | ++*p; | |
58 | off += 60*getint(p); | |
59 | if (**p == ':') { | |
60 | ++*p; | |
61 | off += getint(p); | |
62 | } | |
63 | } | |
64 | return neg ? -off : off; | |
65 | } | |
66 | ||
67 | static void getrule(const char **p, int rule[5]) | |
68 | { | |
69 | int r = rule[0] = **p; | |
70 | ||
71 | if (r!='M') { | |
72 | if (r=='J') ++*p; | |
73 | else rule[0] = 0; | |
74 | rule[1] = getint(p); | |
75 | } else { | |
76 | ++*p; rule[1] = getint(p); | |
77 | ++*p; rule[2] = getint(p); | |
78 | ++*p; rule[3] = getint(p); | |
79 | } | |
80 | ||
81 | if (**p=='/') { | |
82 | ++*p; | |
83 | rule[4] = getoff(p); | |
84 | } else { | |
85 | rule[4] = 7200; | |
86 | } | |
87 | } | |
88 | ||
89 | static void getname(char *d, const char **p) | |
90 | { | |
91 | int i; | |
92 | if (**p == '<') { | |
93 | ++*p; | |
58795582 DG |
94 | for (i=0; (*p)[i] && (*p)[i]!='>'; i++) |
95 | if (i<TZNAME_MAX) d[i] = (*p)[i]; | |
96 | if ((*p)[i]) ++*p; | |
320054e8 | 97 | } else { |
58795582 DG |
98 | for (i=0; ((*p)[i]|32)-'a'<26U; i++) |
99 | if (i<TZNAME_MAX) d[i] = (*p)[i]; | |
320054e8 DG |
100 | } |
101 | *p += i; | |
58795582 | 102 | d[i<TZNAME_MAX?i:TZNAME_MAX] = 0; |
320054e8 DG |
103 | } |
104 | ||
105 | #define VEC(...) ((const unsigned char[]){__VA_ARGS__}) | |
106 | ||
107 | static uint32_t zi_read32(const unsigned char *z) | |
108 | { | |
109 | return (unsigned)z[0]<<24 | z[1]<<16 | z[2]<<8 | z[3]; | |
110 | } | |
111 | ||
112 | static size_t zi_dotprod(const unsigned char *z, const unsigned char *v, size_t n) | |
113 | { | |
114 | size_t y; | |
115 | uint32_t x; | |
116 | for (y=0; n; n--, z+=4, v++) { | |
117 | x = zi_read32(z); | |
118 | y += x * *v; | |
119 | } | |
120 | return y; | |
121 | } | |
122 | ||
123 | static void do_tzset() | |
124 | { | |
125 | char buf[NAME_MAX+25], *pathname=buf+24; | |
126 | const char *try, *s, *p; | |
127 | const unsigned char *map = 0; | |
128 | size_t i; | |
129 | static const char search[] = | |
130 | "/usr/share/zoneinfo/\0/share/zoneinfo/\0/etc/zoneinfo/\0"; | |
131 | ||
132 | s = getenv("TZ"); | |
133 | if (!s) s = "/etc/localtime"; | |
134 | if (!*s) s = __utc; | |
135 | ||
136 | if (old_tz && !strcmp(s, old_tz)) return; | |
137 | ||
138 | for (i=0; i<5; i++) r0[i] = r1[i] = 0; | |
139 | ||
140 | if (zi) __munmap((void *)zi, map_size); | |
141 | ||
142 | /* Cache the old value of TZ to check if it has changed. Avoid | |
143 | * free so as not to pull it into static programs. Growth | |
144 | * strategy makes it so free would have minimal benefit anyway. */ | |
145 | i = strlen(s); | |
146 | if (i > PATH_MAX+1) s = __utc, i = 3; | |
147 | if (i >= old_tz_size) { | |
148 | old_tz_size *= 2; | |
149 | if (i >= old_tz_size) old_tz_size = i+1; | |
150 | if (old_tz_size > PATH_MAX+2) old_tz_size = PATH_MAX+2; | |
151 | old_tz = malloc(old_tz_size); | |
152 | } | |
153 | if (old_tz) memcpy(old_tz, s, i+1); | |
154 | ||
155 | /* Non-suid can use an absolute tzfile pathname or a relative | |
156 | * pathame beginning with "."; in secure mode, only the | |
157 | * standard path will be searched. */ | |
158 | if (*s == ':' || ((p=strchr(s, '/')) && !memchr(s, ',', p-s))) { | |
159 | if (*s == ':') s++; | |
160 | if (*s == '/' || *s == '.') { | |
161 | if (!libc.secure || !strcmp(s, "/etc/localtime")) | |
162 | map = __map_file(s, &map_size); | |
163 | } else { | |
164 | size_t l = strlen(s); | |
165 | if (l <= NAME_MAX && !strchr(s, '.')) { | |
166 | memcpy(pathname, s, l+1); | |
167 | pathname[l] = 0; | |
168 | for (try=search; !map && *try; try+=l+1) { | |
169 | l = strlen(try); | |
170 | memcpy(pathname-l, try, l); | |
171 | map = __map_file(pathname-l, &map_size); | |
172 | } | |
173 | } | |
174 | } | |
175 | if (!map) s = __utc; | |
176 | } | |
177 | if (map && (map_size < 44 || memcmp(map, "TZif", 4))) { | |
178 | __munmap((void *)map, map_size); | |
179 | map = 0; | |
180 | s = __utc; | |
181 | } | |
182 | ||
183 | zi = map; | |
184 | if (map) { | |
185 | int scale = 2; | |
186 | if (sizeof(time_t) > 4 && map[4]=='2') { | |
187 | size_t skip = zi_dotprod(zi+20, VEC(1,1,8,5,6,1), 6); | |
188 | trans = zi+skip+44+44; | |
189 | scale++; | |
190 | } else { | |
191 | trans = zi+44; | |
192 | } | |
193 | index = trans + (zi_read32(trans-12) << scale); | |
194 | types = index + zi_read32(trans-12); | |
195 | abbrevs = types + 6*zi_read32(trans-8); | |
196 | abbrevs_end = abbrevs + zi_read32(trans-4); | |
197 | if (zi[map_size-1] == '\n') { | |
198 | for (s = (const char *)zi+map_size-2; *s!='\n'; s--); | |
199 | s++; | |
200 | } else { | |
201 | const unsigned char *p; | |
202 | __tzname[0] = __tzname[1] = 0; | |
203 | __daylight = __timezone = dst_off = 0; | |
204 | for (p=types; p<abbrevs; p+=6) { | |
205 | if (!p[4] && !__tzname[0]) { | |
206 | __tzname[0] = (char *)abbrevs + p[5]; | |
207 | __timezone = -zi_read32(p); | |
208 | } | |
209 | if (p[4] && !__tzname[1]) { | |
210 | __tzname[1] = (char *)abbrevs + p[5]; | |
211 | dst_off = -zi_read32(p); | |
212 | __daylight = 1; | |
213 | } | |
214 | } | |
215 | if (!__tzname[0]) __tzname[0] = __tzname[1]; | |
216 | if (!__tzname[0]) __tzname[0] = (char *)__utc; | |
217 | if (!__daylight) { | |
218 | __tzname[1] = __tzname[0]; | |
219 | dst_off = __timezone; | |
220 | } | |
221 | return; | |
222 | } | |
223 | } | |
224 | ||
225 | if (!s) s = __utc; | |
226 | getname(std_name, &s); | |
227 | __tzname[0] = std_name; | |
228 | __timezone = getoff(&s); | |
229 | getname(dst_name, &s); | |
230 | __tzname[1] = dst_name; | |
231 | if (dst_name[0]) { | |
232 | __daylight = 1; | |
233 | if (*s == '+' || *s=='-' || *s-'0'<10U) | |
234 | dst_off = getoff(&s); | |
235 | else | |
236 | dst_off = __timezone - 3600; | |
237 | } else { | |
238 | __daylight = 0; | |
239 | dst_off = __timezone; | |
240 | } | |
241 | ||
242 | if (*s == ',') s++, getrule(&s, r0); | |
243 | if (*s == ',') s++, getrule(&s, r1); | |
244 | } | |
245 | ||
246 | /* Search zoneinfo rules to find the one that applies to the given time, | |
247 | * and determine alternate opposite-DST-status rule that may be needed. */ | |
248 | ||
249 | static size_t scan_trans(long long t, int local, size_t *alt) | |
250 | { | |
251 | int scale = 3 - (trans == zi+44); | |
252 | uint64_t x; | |
253 | int off = 0; | |
254 | ||
255 | size_t a = 0, n = (index-trans)>>scale, m; | |
256 | ||
257 | if (!n) { | |
258 | if (alt) *alt = 0; | |
259 | return 0; | |
260 | } | |
261 | ||
262 | /* Binary search for 'most-recent rule before t'. */ | |
263 | while (n > 1) { | |
264 | m = a + n/2; | |
265 | x = zi_read32(trans + (m<<scale)); | |
266 | if (scale == 3) x = x<<32 | zi_read32(trans + (m<<scale) + 4); | |
267 | else x = (int32_t)x; | |
268 | if (local) off = (int32_t)zi_read32(types + 6 * index[m-1]); | |
269 | if (t - off < (int64_t)x) { | |
270 | n /= 2; | |
271 | } else { | |
272 | a = m; | |
273 | n -= n/2; | |
274 | } | |
275 | } | |
276 | ||
277 | /* First and last entry are special. First means to use lowest-index | |
278 | * non-DST type. Last means to apply POSIX-style rule if available. */ | |
279 | n = (index-trans)>>scale; | |
280 | if (a == n-1) return -1; | |
281 | if (a == 0) { | |
282 | x = zi_read32(trans + (a<<scale)); | |
283 | if (scale == 3) x = x<<32 | zi_read32(trans + (a<<scale) + 4); | |
284 | else x = (int32_t)x; | |
285 | if (local) off = (int32_t)zi_read32(types + 6 * index[a-1]); | |
286 | if (t - off < (int64_t)x) { | |
287 | for (a=0; a<(abbrevs-types)/6; a++) { | |
288 | if (types[6*a+4] != types[4]) break; | |
289 | } | |
290 | if (a == (abbrevs-types)/6) a = 0; | |
291 | if (types[6*a+4]) { | |
292 | *alt = a; | |
293 | return 0; | |
294 | } else { | |
295 | *alt = 0; | |
296 | return a; | |
297 | } | |
298 | } | |
299 | } | |
300 | ||
301 | /* Try to find a neighboring opposite-DST-status rule. */ | |
302 | if (alt) { | |
303 | if (a && types[6*index[a-1]+4] != types[6*index[a]+4]) | |
304 | *alt = index[a-1]; | |
305 | else if (a+1<n && types[6*index[a+1]+4] != types[6*index[a]+4]) | |
306 | *alt = index[a+1]; | |
307 | else | |
308 | *alt = index[a]; | |
309 | } | |
310 | ||
311 | return index[a]; | |
312 | } | |
313 | ||
314 | static int days_in_month(int m, int is_leap) | |
315 | { | |
316 | if (m==2) return 28+is_leap; | |
317 | else return 30+((0xad5>>(m-1))&1); | |
318 | } | |
319 | ||
320 | /* Convert a POSIX DST rule plus year to seconds since epoch. */ | |
321 | ||
322 | static long long rule_to_secs(const int *rule, int year) | |
323 | { | |
324 | int is_leap; | |
325 | long long t = __year_to_secs(year, &is_leap); | |
326 | int x, m, n, d; | |
327 | if (rule[0]!='M') { | |
328 | x = rule[1]; | |
329 | if (rule[0]=='J' && (x < 60 || !is_leap)) x--; | |
330 | t += 86400 * x; | |
331 | } else { | |
332 | m = rule[1]; | |
333 | n = rule[2]; | |
334 | d = rule[3]; | |
335 | t += __month_to_secs(m-1, is_leap); | |
336 | int wday = (int)((t + 4*86400) % (7*86400)) / 86400; | |
337 | int days = d - wday; | |
338 | if (days < 0) days += 7; | |
339 | if (n == 5 && days+28 >= days_in_month(m, is_leap)) n = 4; | |
340 | t += 86400 * (days + 7*(n-1)); | |
341 | } | |
342 | t += rule[4]; | |
343 | return t; | |
344 | } | |
345 | ||
346 | /* Determine the time zone in effect for a given time in seconds since the | |
347 | * epoch. It can be given in local or universal time. The results will | |
348 | * indicate whether DST is in effect at the queried time, and will give both | |
349 | * the GMT offset for the active zone/DST rule and the opposite DST. This | |
350 | * enables a caller to efficiently adjust for the case where an explicit | |
351 | * DST specification mismatches what would be in effect at the time. */ | |
352 | ||
353 | void __secs_to_zone(long long t, int local, int *isdst, long *offset, long *oppoff, const char **zonename) | |
354 | { | |
355 | LOCK(lock); | |
356 | ||
357 | do_tzset(); | |
358 | ||
359 | if (zi) { | |
360 | size_t alt, i = scan_trans(t, local, &alt); | |
361 | if (i != -1) { | |
362 | *isdst = types[6*i+4]; | |
363 | *offset = (int32_t)zi_read32(types+6*i); | |
364 | *zonename = (const char *)abbrevs + types[6*i+5]; | |
365 | if (oppoff) *oppoff = (int32_t)zi_read32(types+6*alt); | |
366 | UNLOCK(lock); | |
367 | return; | |
368 | } | |
369 | } | |
370 | ||
371 | if (!__daylight) goto std; | |
372 | ||
373 | /* FIXME: may be broken if DST changes right at year boundary? | |
374 | * Also, this could be more efficient.*/ | |
375 | long long y = t / 31556952 + 70; | |
376 | while (__year_to_secs(y, 0) > t) y--; | |
377 | while (__year_to_secs(y+1, 0) < t) y++; | |
378 | ||
379 | long long t0 = rule_to_secs(r0, y); | |
380 | long long t1 = rule_to_secs(r1, y); | |
381 | ||
382 | if (!local) { | |
383 | t0 += __timezone; | |
384 | t1 += dst_off; | |
385 | } | |
386 | if (t0 < t1) { | |
387 | if (t >= t0 && t < t1) goto dst; | |
388 | goto std; | |
389 | } else { | |
390 | if (t >= t1 && t < t0) goto std; | |
391 | goto dst; | |
392 | } | |
393 | std: | |
394 | *isdst = 0; | |
395 | *offset = -__timezone; | |
396 | if (oppoff) *oppoff = -dst_off; | |
397 | *zonename = __tzname[0]; | |
398 | UNLOCK(lock); | |
399 | return; | |
400 | dst: | |
401 | *isdst = 1; | |
402 | *offset = -dst_off; | |
403 | if (oppoff) *oppoff = -__timezone; | |
404 | *zonename = __tzname[1]; | |
405 | UNLOCK(lock); | |
406 | } | |
407 | ||
408 | static void __tzset() | |
409 | { | |
410 | LOCK(lock); | |
411 | do_tzset(); | |
412 | UNLOCK(lock); | |
413 | } | |
414 | ||
415 | weak_alias(__tzset, tzset); | |
416 | #else | |
417 | void __secs_to_zone(long long t, int local, int *isdst, int *offset, long *oppoff, const char **zonename) | |
418 | { | |
419 | // Minimalist implementation for now. | |
420 | *isdst = 0; | |
421 | *offset = 0; | |
422 | *oppoff = 0; | |
423 | *zonename = __utc; | |
424 | } | |
425 | #endif | |
426 | ||
427 | const char *__tm_to_tzname(const struct tm *tm) | |
428 | { | |
429 | const void *p = tm->__tm_zone; | |
430 | #ifdef __wasilibc_unmodified_upstream // timezone data | |
431 | LOCK(lock); | |
432 | do_tzset(); | |
433 | if (p != __utc && p != __tzname[0] && p != __tzname[1] && | |
434 | (!zi || (uintptr_t)p-(uintptr_t)abbrevs >= abbrevs_end - abbrevs)) | |
435 | p = ""; | |
436 | UNLOCK(lock); | |
437 | #endif | |
438 | return p; | |
439 | } |