termux-packages/packages/glib/glib-gtimezone.c.patch

diff -u -r ../glib-2.54.2/glib/gtimezone.c ./glib/gtimezone.c
--- ../glib-2.54.2/glib/gtimezone.c	2017-07-14 01:03:39.000000000 +0200
+++ ./glib/gtimezone.c	2017-12-21 23:47:57.704190589 +0100
@@ -43,6 +43,10 @@
 #include <windows.h>
 #endif
 
+#ifdef __ANDROID__
+#include <sys/system_properties.h>
+#endif
+
 /**
  * SECTION:timezone
  * @title: GTimeZone
@@ -392,7 +396,109 @@
   gtz->transitions = NULL;
 }
 
-#ifdef G_OS_UNIX
+#ifdef __ANDROID__
+/* Android uses a 'persist.sys.timezone' system property for the
+ * current timezone instead of a /etc/localtime file:
+ * https://android.googlesource.com/platform/ndk/+/android-2.2_r1/docs/system/libc/OVERVIEW.TXT#67
+ *
+ * There are no files under /usr/share/zoneinfo - instead a single
+ * /system/usr/share/zoneinfo/tzdata file is used which contains all
+ * files compiled together with the following tool:
+ * https://android.googlesource.com/platform/system/timezone/+/master/zone_compactor/main/java/ZoneCompactor.java
+ */
+static GBytes *
+zone_info_android (const gchar *identifier)
+{
+  char sys_timezone[PROP_VALUE_MAX];
+  GMappedFile *file;
+  gchar *tzdata;
+  gsize tzdata_length;
+  const gsize index_entry_size = 52;
+  gint32 header_index_offset, header_data_offset;
+  gint32 entry_count, current_index;
+  char* entry_name;
+  gint32 entry_offset, entry_length;
+  GBytes *zoneinfo;
+
+  if (identifier == NULL)
+    {
+      if (__system_property_get ("persist.sys.timezone", sys_timezone) < 1)
+        {
+          g_warning ("__system_property_get(\"persist.sys.timezone\") failed");
+          return NULL;
+        }
+      identifier = sys_timezone;
+    }
+
+  file = g_mapped_file_new ("/system/usr/share/zoneinfo/tzdata", FALSE, NULL);
+  if (file == NULL)
+    {
+      g_warning ("Failed mapping tzdata file");
+      return NULL;
+    }
+
+  tzdata = g_mapped_file_get_contents (file);
+  tzdata_length = g_mapped_file_get_length (file);
+  if (tzdata == NULL || tzdata_length < 24)
+  {
+    g_warning ("Too small tzdata file");
+    goto error;
+  }
+
+  header_index_offset = gint32_from_be (*((gint32_be*) (tzdata + 12)));
+  header_data_offset = gint32_from_be (*((gint32_be*) (tzdata + 16)));
+
+  entry_count = (header_data_offset - header_index_offset) / index_entry_size;
+  if (entry_count < 1)
+    {
+      g_warning("No index entry found");
+      goto error;
+    }
+
+  current_index = 0;
+  while (current_index < entry_count)
+    {
+      entry_name = tzdata + header_index_offset + current_index * index_entry_size;
+      /* The name should be null terminated within the 40 chars. */
+      if (memchr (entry_name, 0, 40) == NULL)
+        {
+          g_warning("Invalid index entry");
+          goto error;
+        }
+
+      if (strcmp (entry_name, identifier) == 0)
+        {
+          entry_offset = gint32_from_be (*(gint32_be*) (entry_name + 40));
+          entry_length = gint32_from_be (*(gint32_be*) (entry_name + 44));
+          if (entry_length == 0)
+            {
+              g_warning ("Invalid tzdata entry with length zero");
+              goto error;
+            }
+          else if (entry_length > 65536 || header_data_offset + entry_offset + entry_length > tzdata_length)
+            {
+              /* Use a reasonable but arbitrary max length of an entry. */
+              g_warning ("Too large tzdata entry length");
+              goto error;
+            }
+
+          zoneinfo = g_bytes_new_with_free_func (tzdata + header_data_offset + entry_offset,
+                                                 entry_length,
+                                                 (GDestroyNotify)g_mapped_file_unref,
+                                                 g_mapped_file_ref (file));
+          g_mapped_file_unref (file);
+          return zoneinfo;
+        }
+      current_index++;
+    }
+
+error:
+  g_mapped_file_unref (file);
+  return NULL;
+}
+
+#elif defined(G_OS_UNIX)
+
 static GBytes*
 zone_info_unix (const gchar *identifier)
 {
@@ -436,6 +542,10 @@
   return zoneinfo;
 }
 
+#endif
+
+#ifdef G_OS_UNIX
+
 static void
 init_zone_from_iana_info (GTimeZone *gtz, GBytes *zoneinfo)
 {
@@ -1387,7 +1497,11 @@
   if (tz->t_info == NULL)
     {
 #ifdef G_OS_UNIX
+# ifdef __ANDROID__
+      GBytes *zoneinfo = zone_info_android (identifier);
+# else
       GBytes *zoneinfo = zone_info_unix (identifier);
+# endif
       if (!zoneinfo)
         zone_for_constant_offset (tz, "UTC");
       else