glib: Update gtimezone.c patch after review

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

Patch submitted at https://bugzilla.gnome.org/show_bug.cgi?id=771304

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	2017-12-09 02:03:46.797229494 +0100
@@ -43,6 +43,14 @@
 #include <windows.h>
 #endif
 
+#ifdef __ANDROID__
+#include <arpa/inet.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/system_properties.h>
+#include <unistd.h>
+#endif
+
 /**
  * SECTION:timezone
  * @title: GTimeZone
@@ -392,7 +399,117 @@
   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)
+{
+  struct tzdata_header
+  {
+    char     version[12];
+    uint32_t index_offset;
+    uint32_t data_offset;
+    uint32_t zonetab_offset;
+  } __attribute__((packed)) header;
+
+  struct tzdata_index_entry
+  {
+    char     name[40];
+    uint32_t offset;
+    uint32_t length;
+    uint32_t unused;
+  } __attribute__((packed)) entry;
+
+  char sys_timezone[PROP_VALUE_MAX];
+  int tzdata_fd;
+
+  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;
+    }
+
+  tzdata_fd = TEMP_FAILURE_RETRY (open ("/system/usr/share/zoneinfo/tzdata", O_RDONLY));
+  if (tzdata_fd < 0)
+  {
+    g_warning ("Failed opening tzdata");
+    return NULL;
+  }
+
+  if (TEMP_FAILURE_RETRY (read (tzdata_fd, &header, sizeof(header)) < (ssize_t) sizeof (header)))
+  {
+    g_warning ("Failed reading tzdata header");
+    goto error;
+  }
+
+  header.index_offset = htonl (header.index_offset);
+  header.data_offset = htonl (header.data_offset);
+
+  uint32_t current_offset = header.index_offset;
+  while (current_offset < header.data_offset)
+    {
+      if (TEMP_FAILURE_RETRY (read (tzdata_fd, &entry, sizeof(entry)) < (ssize_t) sizeof (entry)))
+      {
+        g_warning ("Failed reading tzdata index entry");
+        goto error;
+      }
+
+      if (strcmp (entry.name, identifier) == 0)
+        {
+          entry.offset = htonl (entry.offset);
+          entry.length = htonl (entry.length);
+          if (entry.length == 0)
+            {
+              g_warning ("Invalid tzdata entry with length zero");
+              goto error;
+            }
+
+          if (TEMP_FAILURE_RETRY (lseek (tzdata_fd, header.data_offset + entry.offset, SEEK_SET) == -1))
+            {
+              g_warning ("Failed seeking to tzdata entry");
+              goto error;
+            }
+
+          /* Use a reasonable but arbitrary max length of an entry. */
+          if (entry.length > 65536)
+            {
+              g_warning ("Too large tzdata entry length");
+              goto error;
+            }
+
+          guint8* data = g_malloc (entry.length);
+          if (TEMP_FAILURE_RETRY (read (tzdata_fd, data, entry.length) < entry.length))
+            {
+              g_warning ("Failed reading tzdata entry");
+              g_free (data);
+              goto error;
+            }
+
+          close (tzdata_fd);
+          return g_bytes_new_take (data, entry.length);
+        }
+    }
+
+error:
+  close (tzdata_fd);
+
+  return NULL;
+}
+
+#elif defined(G_OS_UNIX)
+
 static GBytes*
 zone_info_unix (const gchar *identifier)
 {
@@ -436,6 +541,10 @@
   return zoneinfo;
 }
 
+#endif
+
+#ifdef G_OS_UNIX
+
 static void
 init_zone_from_iana_info (GTimeZone *gtz, GBytes *zoneinfo)
 {
@@ -1387,7 +1496,11 @@
   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