timezone: Add support for retrieving current timezone

1 files changed, 217 insertions, 1 deletions

diff --git a/src/timezone.c b/src/timezone.c
index 339542e4..d0045b10 100644
--- a/src/timezone.c
+++ b/src/timezone.c
@@ -23,9 +23,225 @@
 #include <config.h>
 #endif
 
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <dirent.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+
 #include "connman.h"
 
-char *__connman_timezone_lookup(void)
+#define ETC_LOCALTIME		"/etc/localtime"
+#define ETC_SYSCONFIG_CLOCK	"/etc/sysconfig/clock"
+#define USR_SHARE_ZONEINFO	"/usr/share/zoneinfo"
+
+static char *read_key_file(const char *pathname, const char *key)
 {
+	struct stat st;
+	char *map, *ptr, *str;
+	off_t ptrlen, keylen;
+	int fd;
+
+	fd = open(pathname, O_RDONLY);
+	if (fd < 0)
+		return NULL;
+
+	if (fstat(fd, &st) < 0) {
+		close(fd);
+		return NULL;
+	}
+
+	map = mmap(0, st.st_size, PROT_READ, MAP_SHARED, fd, 0);
+	if (map == NULL || map == MAP_FAILED) {
+		close(fd);
+		return NULL;
+	}
+
+	ptr = map;
+	ptrlen = st.st_size;
+	keylen = strlen(key);
+
+	while (ptrlen > keylen + 1) {
+		int cmp = strncmp(ptr, key, keylen);
+
+		if (cmp == 0) {
+			if (ptr == map)
+				break;
+
+			if (*(ptr - 1) == '\n' && *(ptr + keylen) == '=')
+				break;
+		}
+
+		ptr = memchr(ptr + 1, key[0], ptrlen - 1);
+		if (ptr == NULL)
+			break;
+
+		ptrlen = st.st_size - (ptr - map);
+	}
+
+	if (ptr != NULL) {
+		char *end, *val;
+
+		ptrlen = st.st_size - (ptr - map);
+
+		end = memchr(ptr, '\n', ptrlen);
+		if (end != NULL)
+			ptrlen = end - ptr;
+
+		val = memchr(ptr, '"', ptrlen);
+		if (val != NULL) {
+			end = memchr(val + 1, '"', end - val - 1);
+			if (end != NULL)
+				str = strndup(val + 1, end - val - 1);
+			else
+				str = NULL;
+		} else
+			str = strndup(ptr + keylen + 1, ptrlen - keylen - 1);
+	} else
+		str = NULL;
+
+	munmap(map, st.st_size);
+
+	close(fd);
+
+	return str;
+}
+
+static int compare_file(void *src_map, struct stat *src_st,
+						const char *pathname)
+{
+	struct stat dst_st;
+	void *dst_map;
+	int fd, result;
+
+	fd = open(pathname, O_RDONLY);
+	if (fd < 0)
+		return -1;
+
+	if (fstat(fd, &dst_st) < 0) {
+		close(fd);
+		return -1;
+	}
+
+	if (src_st->st_size != dst_st.st_size) {
+		close(fd);
+		return -1;
+	}
+
+	dst_map = mmap(0, dst_st.st_size, PROT_READ, MAP_SHARED, fd, 0);
+	if (dst_map == NULL || dst_map == MAP_FAILED) {
+		close(fd);
+		return -1;
+        }
+
+	result = memcmp(src_map, dst_map, src_st->st_size);
+
+	munmap(dst_map, dst_st.st_size);
+
+	close(fd);
+
+	return result;
+}
+
+static char *find_origin(void *src_map, struct stat *src_st,
+						const char *basepath)
+{
+	DIR *dir;
+	struct dirent *d;
+	char *str, pathname[PATH_MAX];
+
+	dir = opendir(basepath);
+	if (dir == NULL)
+		return NULL;
+
+	while ((d = readdir(dir))) {
+		if (strcmp(d->d_name, ".") == 0 ||
+				strcmp(d->d_name, "..") == 0 ||
+				strcmp(d->d_name, "posix") == 0 ||
+				strcmp(d->d_name, "right") == 0)
+			continue;
+
+		snprintf(pathname, PATH_MAX, "%s/%s", basepath, d->d_name);
+
+		switch (d->d_type) {
+		case DT_REG:
+			if (compare_file(src_map, src_st, pathname) == 0) {
+				closedir(dir);
+				return strdup(d->d_name);
+			}
+			break;
+		case DT_DIR:
+			str = find_origin(src_map, src_st, pathname);
+			if (str != NULL) {
+				closedir(dir);
+				return str;
+			}
+			break;
+		}
+	}
+
+	closedir(dir);
+
 	return NULL;
 }
+
+char *__connman_timezone_lookup(void)
+{
+	struct stat st;
+	void *map;
+	int fd;
+	char *zone;
+
+	zone = read_key_file(ETC_SYSCONFIG_CLOCK, "ZONE");
+
+	DBG("sysconfig zone %s", zone);
+
+	fd = open(ETC_LOCALTIME, O_RDONLY);
+	if (fd < 0) {
+		free(zone);
+		return NULL;
+	}
+
+	if (fstat(fd, &st) < 0)
+		goto done;
+
+	if (S_ISREG(st.st_mode)) {
+		map = mmap(0, st.st_size, PROT_READ, MAP_SHARED, fd, 0);
+		if (map == NULL || map == MAP_FAILED) {
+			free(zone);
+			zone = NULL;
+
+			goto done;
+		}
+
+		if (zone != NULL) {
+			char pathname[PATH_MAX];
+
+			snprintf(pathname, PATH_MAX, "%s/%s",
+						USR_SHARE_ZONEINFO, zone);
+
+			if (compare_file(map, &st, pathname) != 0) {
+				free(zone);
+				zone = NULL;
+			}
+		}
+
+		if (zone == NULL)
+			zone = find_origin(map, &st, USR_SHARE_ZONEINFO);
+
+		munmap(map, st.st_size);
+	} else {
+		free(zone);
+		zone = NULL;
+	}
+
+done:
+	close(fd);
+
+	DBG("localtime zone %s", zone);
+
+	return zone;
+}