Merge pull request tuomasjjrasanen#7 from goncalopp/master

tuomasjjrasanen · tuomasjjrasanen · commit db7059c080c9 · 2016-04-04T21:58:44.000+03:00
Add option to create a device with an existing uinput file descriptor
diff --git a/examples/drop_privileges.py b/examples/drop_privileges.py
@@ -0,0 +1,25 @@
+import uinput
+
+def drop_privileges(uid_name='nobody', gid_name='nogroup'):
+    #https://stackoverflow.com/questions/2699907/dropping-root-permissions-in-python
+    import os, pwd, grp
+    if os.getuid() != 0:
+        return
+    running_uid = pwd.getpwnam(uid_name).pw_uid
+    running_gid = grp.getgrnam(gid_name).gr_gid
+    os.setgroups([])
+    os.setgid(running_gid)
+    os.setuid(running_uid)
+    old_umask = os.umask(077)
+
+
+def main():
+    uinput_fd= uinput.Device.create_uinput_fd()
+    drop_privileges() #no need to be root beyond this line
+
+    events = (uinput.KEY_A,)
+    with uinput.Device(events, fd=uinput_fd) as device:
+        device.emit_click(uinput.KEY_A)
+
+if __name__ == "__main__":
+    main()
diff --git a/src/__init__.py b/src/__init__.py
@@ -80,6 +80,9 @@ def _error_handler(result, fn, args):
         raise RuntimeError("unexpected return value: %s" % result)
     return result
 
+def fdopen():
+    return _libsuinput.suinput_open()
+
 _libsuinput_path = os.path.abspath(os.path.join(os.path.dirname(__file__), "..", "_libsuinput" + sysconfig.get_config_var("SO")))
 _libsuinput = ctypes.CDLL(_libsuinput_path, use_errno=True)
 _libsuinput.suinput_open.errcheck = _open_error_handler
@@ -162,7 +165,7 @@ class Device(object):
     """
 
     def __init__(self, events, name="python-uinput",
-                 bustype=0, vendor=0, product=0, version=0):
+                 bustype=0, vendor=0, product=0, version=0, fd=None):
         self.__events = events
         self.__uinput_fd = -1
         self.__name = name.encode()
@@ -172,7 +175,7 @@ def __init__(self, events, name="python-uinput",
         user_dev.id.vendor = vendor
         user_dev.id.product = product
         user_dev.id.version = version
-        self.__uinput_fd = _libsuinput.suinput_open()
+        self.__uinput_fd = fd or fdopen()
         for ev_spec in self.__events:
             ev_type, ev_code = ev_spec[:2]
             _libsuinput.suinput_enable_event(self.__uinput_fd, ev_type, ev_code)
