diff options
Diffstat (limited to 'libc-top-half/musl/src/time/__tz.c')
-rw-r--r-- | libc-top-half/musl/src/time/__tz.c | 456 |
1 files changed, 456 insertions, 0 deletions
diff --git a/libc-top-half/musl/src/time/__tz.c b/libc-top-half/musl/src/time/__tz.c new file mode 100644 index 0000000..9551503 --- /dev/null +++ b/libc-top-half/musl/src/time/__tz.c @@ -0,0 +1,456 @@ +#include "time_impl.h" +#include <stdint.h> +#include <limits.h> +#include <stdlib.h> +#include <string.h> +#ifdef __wasilibc_unmodified_upstream // timezone data +#include <sys/mman.h> +#include <ctype.h> +#endif +#include "libc.h" +#include "lock.h" +#include "fork_impl.h" + +#define malloc __libc_malloc +#define calloc undef +#define realloc undef +#define free undef + +#ifdef __wasilibc_unmodified_upstream // timezone data +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]; +#endif +const char __utc[] = "UTC"; + +#ifdef __wasilibc_unmodified_upstream // timezone data +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 volatile int lock[1]; +volatile int *const __timezone_lockptr = lock; + +static int getint(const char **p) +{ + unsigned x; + for (x=0; **p-'0'<10U; (*p)++) x = **p-'0' + 10*x; + return x; +} + +static int getoff(const char **p) +{ + int neg = 0; + if (**p == '-') { + ++*p; + neg = 1; + } else if (**p == '+') { + ++*p; + } + int off = 3600*getint(p); + if (**p == ':') { + ++*p; + off += 60*getint(p); + if (**p == ':') { + ++*p; + off += getint(p); + } + } + return neg ? -off : 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] && (*p)[i]!='>'; i++) + if (i<TZNAME_MAX) d[i] = (*p)[i]; + if ((*p)[i]) ++*p; + } else { + for (i=0; ((*p)[i]|32)-'a'<26U; i++) + if (i<TZNAME_MAX) d[i] = (*p)[i]; + } + *p += i; + d[i<TZNAME_MAX?i:TZNAME_MAX] = 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; +} + +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 = "/etc/localtime"; + if (!*s) s = __utc; + + if (old_tz && !strcmp(s, old_tz)) return; + + for (i=0; i<5; i++) r0[i] = r1[i] = 0; + + 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 = __utc, 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); + + int posix_form = 0; + if (*s != ':') { + p = s; + char dummy_name[TZNAME_MAX+1]; + getname(dummy_name, &p); + if (p!=s && (*p == '+' || *p == '-' || isdigit(*p) + || !strcmp(dummy_name, "UTC") + || !strcmp(dummy_name, "GMT"))) + posix_form = 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 (!posix_form) { + if (*s == ':') s++; + if (*s == '/' || *s == '.') { + if (!libc.secure || !strcmp(s, "/etc/localtime")) + 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 = __utc; + } + if (map && (map_size < 44 || memcmp(map, "TZif", 4))) { + __munmap((void *)map, map_size); + map = 0; + s = __utc; + } + + zi = map; + if (map) { + int scale = 2; + if (map[4]!='1') { + 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 (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 *)__utc; + if (!__daylight) { + __tzname[1] = __tzname[0]; + dst_off = __timezone; + } + return; + } + } + + if (!s) s = __utc; + 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 = __timezone; + } + + 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); + if (scale == 3) x = x<<32 | zi_read32(trans + 4); + else x = (int32_t)x; + /* Find the lowest non-DST type, or 0 if none. */ + size_t j = 0; + for (size_t i=abbrevs-types; i; i-=6) { + if (!types[i-6+4]) j = i-6; + } + if (local) off = (int32_t)zi_read32(types + j); + /* If t is before first transition, use the above-found type + * and the index-zero (after transition) type as the alt. */ + if (t - off < (int64_t)x) { + if (alt) *alt = index[0]; + return j/6; + } + } + + /* 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 (!local) { + t0 += __timezone; + t1 += dst_off; + } + if (t0 < t1) { + if (t >= t0 && t < t1) goto dst; + goto std; + } else { + 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); +} + +static void __tzset() +{ + LOCK(lock); + do_tzset(); + UNLOCK(lock); +} + +weak_alias(__tzset, tzset); +#else +void __secs_to_zone(long long t, int local, int *isdst, int *offset, long *oppoff, const char **zonename) +{ + // Minimalist implementation for now. + *isdst = 0; + *offset = 0; + *oppoff = 0; + *zonename = __utc; +} +#endif + +const char *__tm_to_tzname(const struct tm *tm) +{ + const void *p = tm->__tm_zone; +#ifdef __wasilibc_unmodified_upstream // timezone data + LOCK(lock); + do_tzset(); + if (p != __utc && p != __tzname[0] && p != __tzname[1] && + (!zi || (uintptr_t)p-(uintptr_t)abbrevs >= abbrevs_end - abbrevs)) + p = ""; + UNLOCK(lock); +#endif + return p; +} |