diff options
Diffstat (limited to 'libgeome_get_from_timezone.c')
| -rw-r--r-- | libgeome_get_from_timezone.c | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/libgeome_get_from_timezone.c b/libgeome_get_from_timezone.c new file mode 100644 index 0000000..a9d3b69 --- /dev/null +++ b/libgeome_get_from_timezone.c @@ -0,0 +1,221 @@ +/* See LICENSE file for copyright and license details. */ +#include "common.h" + + +static char * +get_timezone(struct libgeome_context *ctx, int *env_determined_out) +{ + const char *tzdir; + const char *tz; + char *tzbuf = NULL; + char *ret; + size_t tzdirlen; + + tz = getenv("TZ"); + *env_determined_out = !!tz; + if (!tz) { + tzdir = getenv("TZDIR"); + if (!tzdir) + tzdir = TZDIR; + tz = tzbuf = libgeome_util_areadlink(ctx, TZFILE); + if (!tz) + return NULL; + tzdirlen = strlen(tzdir); + if (!strncmp(tz, tzdir, tzdirlen) && tz[tzdirlen] == '/') { + tz = &tz[tzdirlen]; + while (*tz == '/') + tz++; + } + } + + ret = strdup(tz); + if (!ret) + ctx->print_error(ctx, "strdup: %s\n", strerror(errno)); + free(tzbuf); + return ret; +} + + +static int +get_timezone_location3(struct libgeome_context *ctx, const char *tz, const char *tabfile, struct location *location_out) +{ + const char *tzdir, *coords; + char *path, *line = NULL, *p; + size_t size = 0, tzlen = strlen(tz); + int lat_sign, lat_degrees, lat_minutes, lat_seconds = 0; + int lon_sign, lon_degrees, lon_minutes, lon_seconds = 0; + ssize_t len; + FILE *f; + + tzdir = getenv("TZDIR"); + if (!tzdir) + tzdir = TZDIR; + + path = malloc(strlen(tzdir) + strlen(tabfile) + sizeof("/")); + if (!path) { + ctx->print_error(ctx, "malloc: %s\n", strerror(errno)); + return -1; + } + stpcpy(stpcpy(stpcpy(path, tzdir), "/"), tabfile); + + f = fopen(path, "r"); + if (!f) { + if (errno == ENOENT) + ctx->print_debug(ctx, "fopen %s r: %s\n", path, strerror(errno)); + else + ctx->print_error(ctx, "fopen %s r: %s\n", path, strerror(errno)); + free(path); + return -1; + } + +again: + while (len = getline(&line, &size, f), len >= 0) { + p = line; + for (;; p++) { + if (!*p || *p == '\r' || *p == '\n' || *p == '#') + goto next_line; + if (*p == '\t') + break; + } + + coords = ++p; + for (;; p++) { + if (!*p || *p == '\r' || *p == '\n' || *p == '#') + goto next_line; + if (*p == '\t') + break; + } + *p++ = '\0'; + + if (strncmp(p, tz, tzlen)) + goto next_line; + p = &p[tzlen]; + if (*p && *p != '\r' && *p != '\n' && *p != '#' && *p != '\t') + goto next_line; + + goto found_coords; + + next_line:; + } + if (!feof(f)) { + if (errno == EINTR) { + clearerr(f); + goto again; + } + ctx->print_error(ctx, "getline %s: %s\n", path, strerror(errno)); + } + ctx->print_debug(ctx, "entry for timezone %s not found in %s\n", tz, path); + + free(line); + free(path); + fclose(f); + return -1; + +bad_coords: + ctx->print_debug(ctx, "malformatted coordinates for %s in %s\n", tz, path); + free(line); + free(path); + fclose(f); + return -1; + +found_coords: + if (coords[0] != '+' && coords[0] != '-') + goto bad_coords; + if (!isdigit(coords[1]) || !isdigit(coords[2])) + goto bad_coords; + if (!isdigit(coords[3]) || !isdigit(coords[4])) + goto bad_coords; + lat_sign = coords[0] == '-' ? -1 : +1; + lat_degrees = (coords[1] & 15) * 10 + (coords[2] & 15); + lat_minutes = (coords[3] & 15) * 10 + (coords[4] & 15); + coords = &coords[5]; + if (isdigit(coords[0]) && isdigit(coords[1])) { + lat_seconds = (coords[0] & 15) * 10 + (coords[1] & 15); + coords = &coords[2]; + } + + if (coords[0] != '+' && coords[0] != '-') + goto bad_coords; + if (!isdigit(coords[1]) || !isdigit(coords[2]) || !isdigit(coords[3])) + goto bad_coords; + if (!isdigit(coords[4]) || !isdigit(coords[5])) + goto bad_coords; + lon_sign = coords[0] == '-' ? -1 : +1; + lon_degrees = (coords[1] & 15) * 100 + (coords[2] & 15) * 10 + (coords[3] & 15); + lon_minutes = (coords[4] & 15) * 10 + (coords[5] & 15); + coords = &coords[6]; + if (isdigit(coords[0]) && isdigit(coords[1])) { + lon_seconds = (coords[0] & 15) * 10 + (coords[1] & 15); + coords = &coords[2]; + } + + if (*coords) + goto bad_coords; + + if (lat_degrees > 90 || lon_degrees > 180) + goto bad_coords; + if (lat_minutes >= 60 || lon_minutes >= 60) + goto bad_coords; + if (lat_seconds >= 60 || lon_seconds >= 60) + goto bad_coords; + if (lat_degrees == 90 && lat_minutes + lat_seconds) + goto bad_coords; + if (lon_degrees == 180 && lon_minutes + lon_seconds) + goto bad_coords; + + location_out->latitude = (double)lat_degrees; + location_out->latitude += (double)lat_minutes / 60; + location_out->latitude += (double)lat_seconds / 3600; + location_out->latitude *= (double)lat_sign; + + location_out->longitude = (double)lon_degrees; + location_out->longitude += (double)lon_minutes / 60; + location_out->longitude += (double)lon_seconds / 3600; + location_out->longitude *= (double)lon_sign; + + free(line); + free(path); + fclose(f); + return 0; +} + + +static int +get_timezone_location(struct libgeome_context *ctx, const char *tz, struct location *location_out) +{ + if (!get_timezone_location3(ctx, tz, "zone1970.tab", location_out)) + return 0; + if (!get_timezone_location3(ctx, tz, "zone.tab", location_out)) + return 0; + if (!get_timezone_location3(ctx, tz, "zonenow.tab", location_out)) + return 0; + return -1; +} + + +int +libgeome_get_from_timezone(struct libgeome_context *ctx, struct libgeome_data *out) +{ + struct location location; + char *tz; + + tz = get_timezone(ctx, &(int){0}); + if (!tz) + return -1; + if (get_timezone_location(ctx, tz, &location)) { + free(tz); + return -1; + } + free(tz); + + out->requested_data &= LIBGEOME_DATUM_LATITUDE | LIBGEOME_DATUM_LONGITUDE; + if (out->requested_data) { + if (out->requested_data & LIBGEOME_DATUM_LATITUDE) + out->latitude = location.latitude; + if (out->requested_data & LIBGEOME_DATUM_LONGITUDE) + out->longitude = location.longitude; + } + + return 0; + +} |