ICU-11992 uprv_tzname doesn't return valid time zone on Android
diff --git a/icu4c/source/common/putil.cpp b/icu4c/source/common/putil.cpp
index 905402c..40232fc 100644
--- a/icu4c/source/common/putil.cpp
+++ b/icu4c/source/common/putil.cpp
@@ -118,11 +118,15 @@
# ifndef _XPG4_2
# define _XPG4_2
# endif
+# elif U_PLATFORM == U_PF_ANDROID
+# include <sys/system_properties.h>
+# include <dlfcn.h>
# endif
#elif U_PLATFORM == U_PF_QNX
# include <sys/neutrino.h>
#endif
+
/*
* Only include langinfo.h if we have a way to get the codeset. If we later
* depend on more feature, we can test on U_HAVE_NL_LANGINFO.
@@ -1043,9 +1047,53 @@
}
#endif
+#if U_PLATFORM == U_PF_ANDROID
+typedef int(system_property_read_callback)(const prop_info* info,
+ void (*callback)(void* cookie,
+ const char* name,
+ const char* value,
+ uint32_t serial),
+ void* cookie);
+typedef int(system_property_get)(const char*, char*);
+
+static char gAndroidTimeZone[PROP_VALUE_MAX] = { '\0' };
+
+static void u_property_read(void* cookie, const char* name, const char* value,
+ uint32_t serial) {
+ uprv_strcpy((char* )cookie, value);
+}
+#endif
+
U_CAPI void U_EXPORT2
uprv_tzname_clear_cache(void)
{
+#if U_PLATFORM == U_PF_ANDROID
+ /* Android's timezone is stored in system property. */
+ gAndroidTimeZone[0] = '\0';
+ void* libc = dlopen("libc.so", RTLD_NOLOAD);
+ if (libc) {
+ /* Android API 26+ has new API to get system property and old API
+ * (__system_property_get) is deprecated */
+ system_property_read_callback* property_read_callback =
+ (system_property_read_callback*)dlsym(
+ libc, "__system_property_read_callback");
+ if (property_read_callback) {
+ const prop_info* info =
+ __system_property_find("persist.sys.timezone");
+ if (info) {
+ property_read_callback(info, &u_property_read, gAndroidTimeZone);
+ }
+ } else {
+ system_property_get* property_get =
+ (system_property_get*)dlsym(libc, "__system_property_get");
+ if (property_get) {
+ property_get("persist.sys.timezone", gAndroidTimeZone);
+ }
+ }
+ dlclose(libc);
+ }
+#endif
+
#if defined(CHECK_LOCALTIME_LINK) && !defined(DEBUG_SKIP_LOCALTIME_LINK)
gTimeZoneBufferPtr = NULL;
#endif
@@ -1084,7 +1132,11 @@
/* This code can be temporarily disabled to test tzname resolution later on. */
#ifndef DEBUG_TZNAME
+#if U_PLATFORM == U_PF_ANDROID
+ tzid = gAndroidTimeZone;
+#else
tzid = getenv("TZ");
+#endif
if (tzid != NULL && isValidOlsonID(tzid)
#if U_PLATFORM == U_PF_SOLARIS
/* When TZ equals localtime on Solaris, check the /etc/localtime file. */
