bitbake: toaster: fix timezone detection

This patch replaces faulty timezone detection with a version
that simply reads the TZ environment variable if it is set.

If the TZ is not set, we do a reverse match search among known
timezone definitions and take the first match.

    [YOCTO #5499]

(Bitbake rev: 3a0a556a65368f02635606e4eb707ca08e25007a)

Signed-off-by: Alexandru DAMIAN <alexandru.damian@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/toaster/toastermain/settings.py

@@ -50,9 +50,23 @@ ALLOWED_HOSTS = []
 # although not all choices may be available on all operating systems.
 # In a Windows environment this must be set to your system time zone.
 
-# Always use local computer's time zone
-import time
-TIME_ZONE = time.tzname[0]
+# Always use local computer's time zone, find
+import os, hashlib
+if 'TZ' in os.environ:
+    TIME_ZONE = os.environ['TZ']
+else:
+    # need to read the /etc/localtime file which is the libc standard
+    # and do a reverse-mapping to /usr/share/zoneinfo/;
+    # since the timezone may match any number of identical timezone definitions,
+
+    zonefilelist = {}
+    ZONEINFOPATH = '/usr/share/zoneinfo/'
+    for dirpath, dirnames, filenames in os.walk(ZONEINFOPATH):
+        for fn in filenames:
+            filepath = os.path.join(dirpath, fn)
+            zonefilelist[hashlib.md5(open(filepath).read()).hexdigest()] = filepath.lstrip(ZONEINFOPATH).strip()
+
+    TIME_ZONE = zonefilelist[hashlib.md5(open('/etc/localtime').read()).hexdigest()]
 
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