Description of problem:

CUPs help indicates the following (from doc/help/network.html): 
sanitize_title=no - Specifies that the job title string should not be restricted to ASCII characters.
sanitize_title=yes - Specifies that the job title string should be restricted to ASCII characters.

The default is sanitize_title=yes.  The above indicates that NON-ASCII characters are restricted (replaced with "_"), but in reality all characters that are not ASCII alphanumeric or space are restricted (for example: ?, $, =).

The relevant section of backend/lpd.c (~line 480):

  if (sanitize_title)
  {
   /*
    * Sanitize the title string so that we don't cause problems on
    * the remote end...
    */

    char *ptr;

    for (ptr = title; *ptr; ptr ++)
      if (!isalnum(*ptr & 255) && !isspace(*ptr & 255))
    *ptr = '_';
  }


Either the code or the documentation should be corrected since the documented operation is misleading.


Possible patch to operate as documented:
--- backend/lpd.c.orig  2013-07-24 10:15:51.102608626 -0500
+++ backend/lpd.c       2013-07-24 10:16:17.495839026 -0500
@@ -493,7 +493,7 @@
     char *ptr;
 
     for (ptr = title; *ptr; ptr ++)
-      if (!isalnum(*ptr & 255) && !isspace(*ptr & 255))
+      if (!isprint(*ptr & 255))
        *ptr = '_';
   }
 


Version-Release number of selected component (if applicable):
specific: cups-1.4.2-50.el6_4.4.x86_64
All versions of cups from 1.4.2-current are affected.

How reproducible:
Always

Steps to Reproduce:
1. Set "Loglevel debug" in /etc/cups/cups.conf
2. Restart CUPS
3. Print test document to any LPD network printer: lpr -Ptestprinter -J TEST=TEST ./test.txt

Actual results:
In debug output (/var/log/cups/error_log): "JTEST_TEST"

Expected results:
In debug output (/var/log/cups/error_log): "JTEST=TEST"

Additional info:
Work around by setting sanitize_title=no in LPD printer URI if the remote end can handle it.