Description: Filter printers based on PRINTER_LIST
Author: Julien Desfossez at Revolution Linux

=== modified file 'cups-1.3.9/cups/ipp.c'
--- a/cups/ipp.c
+++ b/cups/ipp.c
@@ -77,6 +77,8 @@
  *   ippNewResponse()	     - Allocate a new IPP response message.
  *   ippRead()		     - Read data for an IPP message from a HTTP
  *			       connection.
+ *   ippFilterPrinters()     - Filter printer list based on an environment
+ *			       variable
  *   ippReadFile()	     - Read data for an IPP message from a file.
  *   ippReadIO()	     - Read data for an IPP message.
  *   ippSetBoolean()	     - Set a boolean value in an attribute.
@@ -2762,6 +2764,120 @@
   return (temp);
 }
 
+/*
+ * 'ippFilterPrinters()' - Filter printer list based on environment variables
+ */
+ipp_state_t                         /* O - Current state */
+ippFilterPrinters(ipp_t      *ipp)  /* I - IPP data */
+{
+  char *env_printer_list = NULL;
+  char *result_printer_list;
+  char delim_printers[] = ",";
+  char **printer_list_array;
+  char *default_printer_env;
+  int printer_list_size = 0;
+  ipp_attribute_t	*filtertmpattr;
+  ipp_attribute_t	*filtertmpattr2;
+  int i = 0;
+  int j = 0;
+  int found = 0;
+  int printer_name_found = 0;
+  int len = 0;
+  int last_null = 0;
+
+  /*
+   * First we create an array from PRINTER and PRINTER_LIST
+   */
+  if(getenv("PRINTER") != NULL) {
+    default_printer_env = getenv("PRINTER");
+    printer_list_size++;
+  } else {
+    default_printer_env = (char *)malloc(sizeof(char));
+    default_printer_env = "";
+  }
+
+  env_printer_list = strdup(getenv("PRINTER_LIST"));
+  result_printer_list = strtok(env_printer_list, delim_printers);
+  while(result_printer_list) {
+    if(default_printer_env && strcasecmp(result_printer_list, default_printer_env) != 0)
+      printer_list_size++;
+    result_printer_list = strtok( NULL, delim_printers);
+  }
+
+  printer_list_array = (char **)malloc(printer_list_size * sizeof(char *));
+
+  env_printer_list = strdup(getenv("PRINTER_LIST"));
+
+  result_printer_list = strtok(env_printer_list, delim_printers);
+  while(result_printer_list) {
+    /*
+     * Don't add the default printer if it's defined
+     */
+    if(strcasecmp(result_printer_list, default_printer_env) != 0) {
+      printer_list_array[i] = (char *)malloc(sizeof(result_printer_list));
+      printer_list_array[i++] = result_printer_list;
+    }
+    result_printer_list = strtok( NULL, delim_printers);
+  }
+
+  if(strcasecmp(default_printer_env, "") != 0)
+    printer_list_array[printer_list_size-1] = default_printer_env;
+
+  // number of attributes
+  for (filtertmpattr = ipp->attrs; filtertmpattr != NULL; filtertmpattr = filtertmpattr->next) {
+    len++;
+  }
+  ipp_attribute_t* array[len];
+
+  for (filtertmpattr = ipp->attrs; filtertmpattr != NULL; filtertmpattr = filtertmpattr->next) {
+    array[j++] = filtertmpattr;
+  }
+
+  for (j=0; j<len; j++) {
+    filtertmpattr = array[j];
+    // if the current attribute is a printer_name, find it in the list
+    if ((filtertmpattr->value_tag == IPP_TAG_NAME) && 
+                   (strcasecmp(filtertmpattr->name, "printer-name") == 0)) {
+      printer_name_found = 1;
+
+      // compare the current printer with the values in the list
+      for(i = 0; i < printer_list_size; i++) {
+        if (printer_list_array[i] &&  filtertmpattr->values[0].string.text && 
+                   (strcasecmp(filtertmpattr->values[0].string.text, printer_list_array[i]) == 0)) {
+          found = 1;
+        }
+      }
+    }
+
+    // last attribute of a printer (separator) or last attribute
+    if (filtertmpattr->value_tag == IPP_TAG_ZERO || filtertmpattr->next == NULL) {
+      if(found == 0 && printer_name_found == 1) {    // not found so we remove it
+        // First printer
+        if(last_null == 0) {
+           ipp->attrs = filtertmpattr->next;
+        } else {
+           // Printer in the middle
+           (array[last_null])->next = filtertmpattr->next;
+        }
+      } else {
+        // the last known good printer
+        last_null = j;
+      }
+        printer_name_found = 0;
+        found = 0;
+    }
+  }
+
+  // remove the last IPP_TAG_ZERO if the last element in the list
+  for (filtertmpattr = ipp->attrs; filtertmpattr != NULL; filtertmpattr = filtertmpattr->next){
+    if (filtertmpattr->value_tag == IPP_TAG_ZERO && filtertmpattr->next == NULL){
+      filtertmpattr2->next = NULL;
+    }
+    filtertmpattr2 = filtertmpattr;
+  }
+  return 0;
+}
+
 
 /*
  *  'ippNewRequest()' - Allocate a new IPP request message.
@@ -3112,6 +3228,8 @@
 	    */
 
             DEBUG_puts("2ippReadIO: IPP_TAG_END.");
+            if(getenv("PRINTER_LIST"))
+	            ippFilterPrinters(ipp);
 
 	    ipp->state = IPP_STATE_DATA;
 	    break;