Minor changes after latest merge

Author: zdohnal

NEWS

@@ -4,6 +4,7 @@
 - github #174 - put back notification about missing pysmbc
 - update .pot file because of fix #174
 - python3.9 - xml module removed elem.getchildren() method, use list(elem)
+- Make the matching rule of printer device path more flexible (#183)
 
 1.5.12 changes
 --------------

udev/70-printers.rules

@@ -1,4 +1,11 @@
+# UDEV rules for USB devices - ENV variables can be monitored
+# via 'sudo udevadm monitor --udev --subsystem-match=usb --property'
 # Low-level USB device add trigger
 ACTION=="add", SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", ENV{ID_USB_INTERFACES}=="*:0701??:*", TAG+="systemd", ENV{SYSTEMD_WANTS}="configure-printer@usb-$env{BUSNUM}-$env{DEVNUM}.service"
 # Low-level USB device remove trigger
+# Interface types:
+# 7/1/1 - device with unidirectional USB, managed by usb backend
+# 7/1/2 - device with bidirectional USB, managed by usb backend
+# 7/1/3 - device with special USB protocol, managed by hp backend
+# 7/1/4 - device with IPP over USB protocol, managed by ipp-usb daemon
 ACTION=="remove", SUBSYSTEM=="usb", ENV{INTERFACE}=="7/1/*", RUN+="udev-configure-printer remove %p"

udev/udev-configure-printer.c

@@ -1792,28 +1792,25 @@ disable_queue (const char *printer_uri, void *context)
   httpClose (cups);
 }
 
-static int
-device_exists(char *device_path)
+/*
+ * 'device_exists()' - Checks if the device really exists within filesystem.
+ */
+
+static int                          /* 0 if not found, 1 if found*/
+device_exists(
+    char *device_path)              /* I - string representing device path of USB device*/
 {
   char full_path[100];
   struct stat buffer;
-  int exist = -1;
-  int path_length=strlen(device_path);
-  // 5 is the length of "/sys" + null
-  snprintf(full_path, path_length + 5, "%s%s", "/sys", device_path);
 
-  // check the exist of this device
-  if (stat(full_path, &buffer) == 0){
-    exist = 1;
-  }
+  // create a full path
+  snprintf(full_path, sizeof(full_path), "%s%s", "/sys", device_path);
 
-  return exist;
-}
+  // check the exist of this device
+  if (stat(full_path, &buffer) == 0)
+    return 1;
 
-static char*
-compare_usb_uri(char *uri_store, char *uri_uevent)
-{
-  return strstr(uri_uevent, uri_store);
+  return 0;
 }
 
 static int
@@ -1855,7 +1852,19 @@ do_remove (const char *devaddr)
   prev = &map->entries;
   for (entry = map->entries; entry; entry = entry->next)
   {
- if (compare_usb_uri(entry->devpath, devpath) !=NULL && device_exists(entry->devpath) == -1)
+    /* devpath is a string obtained from USB 'remove' event
+     * and it is usually longer or the same as the string
+     * from the main USB 'add' event, when the device is added.
+     *
+     * Both strings represent device paths in filesystem without '/sys':
+     * f.e.:
+     * /devices/pci0000:00/0000:00:14.0/usb3/3-2
+     *
+     * When we are disabling the queue, we check if the string from 'add'
+     * event is a substring of string from 'remove' event and the actual
+     * device doesn't exist anymore.
+     */
+    if (strstr(devpath, entry->devpath) != NULL && !device_exists(entry->devpath))
 	{
 	  uris = &entry->uris;
 	  break;