bug fixes + concurrent X11 threads

This commit updates the author.
It also contains the following changes:
- initializes Xlib support for concurrent threads
- fix minor device number calculation for large values
- fix crash if there are multiple pty slave folders

fix minor device number calculation for large values

Unfortunately the extraction of the minor device number from the tty_nr
was wrong.
The man page of procfs states that 'The minor device number is contained
[in the tty_nr] in the combination of bits 31 to 20 and 7 to 0' but it did not state
that you need to shift the bits together.
So I just missed that step.
This commit adds the correct placement of the bits to the calculation of the minor device number.

fix crash if there are multiple pty slave folders

If a system uses multiple pty slave folders it is possible that while
searching for the pty file a FileNotFoundError is raised which crashs
the program. In this case the correct behavior would be to look for the
pty file in the next folder. So this commit ignores the
FileNotFoundError for the call of the stat function.

examples/fzfimg.sh

@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 # This is just an example how ueberzug can be used with fzf.
-# Copyright (C) 2019  Nico Bäurer
+# Copyright (C) 2019  seebye
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by

examples/mastodon.sh

@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 # This is just an example how ueberzug can be used.
-# Copyright (C) 2019  Nico Bäurer
+# Copyright (C) 2019  seebye
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by

ueberzug/X/X.c

@@ -1,14 +1,36 @@
 #include "python.h"
+
+#include <X11/Xlib.h>
+
+#include "util.h"
 #include "display.h"
 #include "window.h"
 #include "Xshm.h"
 
 
+static PyObject *
+X_init_threads(PyObject *self) {
+    if (XInitThreads() == 0) {
+        raise(OSError, "Xlib concurrent threads initialization failed.");
+    }
+    Py_RETURN_NONE;
+}
+
+
+static PyMethodDef X_methods[] = {
+    {"init_threads", (PyCFunction)X_init_threads,
+     METH_NOARGS,
+     "Initializes Xlib support for concurrent threads."},
+    {NULL}  /* Sentinel */
+};
+
+
 static PyModuleDef module = {
     PyModuleDef_HEAD_INIT,
     .m_name = "ueberzug.X",
     .m_doc = "Modul which implements the interaction with the Xshm extension.",
     .m_size = -1,
+    .m_methods = X_methods,
 };
 
 

ueberzug/__init__.py

@@ -4,4 +4,4 @@ __description__ ='ueberzug is a command line util which allows to display images
 __url_repository__ = 'https://github.com/seebye/ueberzug'
 __url_bug_reports__ = 'https://github.com/seebye/ueberzug/issues'
 __url_project__ = __url_repository__
-__author__ = 'Nico Bäurer'
+__author__ = 'seebye'

ueberzug/__main__.py

@@ -27,7 +27,7 @@ Layer options:
 
 
 License:
-    ueberzug  Copyright (C) 2018  Nico Bäurer
+    ueberzug  Copyright (C) 2018  seebye
     This program comes with ABSOLUTELY NO WARRANTY.
     This is free software, and you are welcome to redistribute it
     under certain conditions.

ueberzug/layer.py

@@ -212,6 +212,7 @@ def main(options):
     error_handler = error_processor_factory(parser_object)
     view = View()
     tools = Tools(image_loader, parser_object, error_handler)
+    X.init_threads()
     display = X.Display()
     window_factory = ui.CanvasWindow.Factory(display, view)
     window_infos = xutil.get_parent_window_infos(display)

ueberzug/process.py

@@ -4,7 +4,6 @@ import functools
 
 
 MAX_PROCESS_NAME_LENGTH = 15
-MINOR_DEVICE_NUMBER_MASK = 0b1111_1111_1111_0000_0000_0000_1111_1111
 
 
 @functools.wraps(os.getpid)
@@ -103,6 +102,29 @@ def get_parent_pid(pid: int):
     return int(process_info['ppid'])
 
 
+def calculate_minor_device_number(tty_nr: int):
+    """Calculates the minor device number contained
+    in a tty_nr of a stat file of the procfs.
+
+    Args:
+        tty_nr (int):
+            a tty_nr of a stat file of the procfs
+
+    Returns:
+        int: the minor device number contained in the tty_nr
+    """
+    TTY_NR_BITS = 32
+    FIRST_BITS = 8
+    SHIFTED_BITS = 12
+    FIRST_BITS_MASK = 0xFF
+    SHIFTED_BITS_MASK = 0xFFF00000
+    minor_device_number = (
+        (tty_nr & FIRST_BITS_MASK) +
+        ((tty_nr & SHIFTED_BITS_MASK)
+         >> (TTY_NR_BITS - SHIFTED_BITS - FIRST_BITS)))
+    return minor_device_number
+
+
 def get_pty_slave(pid: int):
     """Determines control device file
     of the pty slave of the process with the given pid.
@@ -123,12 +145,15 @@ def get_pty_slave(pid: int):
     pty_slave_folders = get_pty_slave_folders()
     process_info = get_info(pid)
     tty_nr = int(process_info['tty_nr'])
-    minor_device_number = tty_nr & MINOR_DEVICE_NUMBER_MASK
+    minor_device_number = calculate_minor_device_number(tty_nr)
 
     for folder in pty_slave_folders:
         device_path = f'{folder}/{minor_device_number}'
 
-        if tty_nr == os.stat(device_path).st_rdev:
-            return device_path
+        try:
+            if tty_nr == os.stat(device_path).st_rdev:
+                return device_path
+        except FileNotFoundError:
+            pass
 
     return None