Workaround for glibc > 2.33 breaking web engine

src/calibre/gui2/__init__.py

@@ -399,6 +399,26 @@ def is_widescreen():
     return _is_widescreen
 
 
+def disable_webengine_sandbox_if_needed():
+    # See https://sourceware.org/glibc/wiki/Glibc%20Timeline
+    if not isfrozen or iswindows or ismacos or QT_VERSION >= 0x60000:
+        return
+    import ctypes
+    libc = ctypes.CDLL(None)
+    try:
+        f = libc.gnu_get_libc_version
+    except AttributeError:
+        return
+    f.restype = ctypes.c_char_p
+    ver = f().decode('ascii')
+    q = tuple(map(int, ver.split('.')))
+    if q >= (2, 34):
+        setattr(disable_webengine_sandbox_if_needed, 'done', True)
+        setattr(disable_webengine_sandbox_if_needed, 'orig_val', os.environ.get('QTWEBENGINE_DISABLE_SANDBOX'))
+        print('Disabling Qt WebEngine sandbox as version of glibc on this system will break it', file=sys.stderr)
+        os.environ['QTWEBENGINE_DISABLE_SANDBOX'] = '1'
+
+
 def extension(path):
     return os.path.splitext(path)[1][1:].lower()
 
@@ -925,6 +945,7 @@ class Application(QApplication):
 
     def __init__(self, args, force_calibre_style=False, override_program_name=None, headless=False, color_prefs=gprefs, windows_app_uid=None):
         self.ignore_palette_changes = False
+        disable_webengine_sandbox_if_needed()
         QNetworkProxyFactory.setUseSystemConfiguration(True)
         # Allow import of webengine after construction of QApplication on new
         # enough PyQt
@@ -1301,6 +1322,8 @@ def sanitize_env_vars():
     else:
         env_vars = {}
 
+    if getattr(disable_webengine_sandbox_if_needed, 'done', False):
+        env_vars['QTWEBENGINE_DISABLE_SANDBOX'] = None
     originals = {x:os.environ.get(x, '') for x in env_vars}
     changed = {x:False for x in env_vars}
     for var, suffix in iteritems(env_vars):
@@ -1313,6 +1336,8 @@ def sanitize_env_vars():
                 del os.environ[var]
             changed[var] = True
 
+    if getattr(disable_webengine_sandbox_if_needed, 'orig_val', False):
+        os.environ['QTWEBENGINE_DISABLE_SANDBOX'] = disable_webengine_sandbox_if_needed.orig_val
     try:
         yield
     finally: