Add printer wizzard and auto-discoverred shows different list of printers

[michaelrsweet]

Version: 1.2-current
CUPS.org User: georgeliuyue

Reporting this problem only for cups-1.2svn-r5643
The auto-discovered list of printers and the list of printers in printer drop down box from add printer wizzard(APW) are not identical.

Some printer listed in APW's drop down list is not in the list auto-discover displays.

Some printers listed in auto-discovery page are shown as Unknown 123.456.789.123 in APW. (IP address is correct)

Have roughly 20 printers in my subnet.

[michaelrsweet]

CUPS.org User: mike

Any printers with "Unknown" make and model strings are ignored on the main administration page for a couple reasons. First, we have no way to automatically select a driver. Second, some backends are either unable to report the make and model, like the serial backend, or are placeholders for particular drivers or backends.

Thus, the only printers that can be added automatically are reported, and the rest (including URI schemes like "ipp" and "socket") can be selected by clicking on Add Printer and doing all of the association manually.

[michaelrsweet]

CUPS.org User: mike

[post to cups.bugs]

There probably IS a memory accessing problem in CUPS 1.2.
Please keep this bug Open.

From Add Printer Wizzard (APW), some printers are listed as Unknown.
Those unknown printers have been auto-discovered (with valid manufacture
and model name)

Way to reproduce:

1. Click Administration. A list a printers will be discovered.
2. Click Add Printer, provide a name and examine the printer drop down
   box. (In many cases, there'll be printer named "Unknown". The unknown
   printers have been discovered in the previous step.)
3. Click the back button to the main page of administration. Click Add
   Printer and check the printer list again. Printers of different IP
   addresses would be marked "Unknown". This list most likely is not the
   same as the printer in step 2.

I have roughly 20 printers in my subnet.

[michaelrsweet]

CUPS.org User: mike

It is highly unlikely there is a memory accessing problem (it would show up quickly in a lot of different places), but we'll need the full debug output of the SNMP backend to determine what is going wrong.

Please attach the output of the following commands:

CUPS_DEBUG_LEVEL=3 /usr/lib/cups/backend/snmp
lpinfo -l -v

Thanks!

[michaelrsweet]

CUPS.org User: georgeliuyue

Reproduced the problem on cups-1.2.x 5682, attached some debug files.

Attached png files shows a auto-discovery screen, which list all the printers in the subnet correctly.

After clicking "Add Printer", some "Unknown" printer showed up, but the Unknown printer's IP was previously shown in the auto-discovery screen, and printer name is known.

Made two runs of snmp backend and attached snmp.log and snmp.log1, each run returns different number of "Unknown" printers.

The unknown printer covers Ricoh and HP brand.

[michaelrsweet]

CUPS.org User: mike

Hmm, will see if I can find a connection - both logs show the received packets, but in some cases we are ignoring the responses...

[michaelrsweet]

CUPS.org User: mike

Try the attached patch and let me know if it resolves the issue...

[michaelrsweet]

CUPS.org User: georgeliuyue

I applied the patch against CUPS-1.2svn-r5688, and the patch worked. This bug can be closed.

Thanks Mike.

[michaelrsweet]

"str1774.patch":

Index: snmp.c

--- snmp.c (revision 5731)
+++ snmp.c (working copy)
@@ -1203,7 +1203,7 @@
compare_cache(snmp_cache_t a, / I - First cache entry /
snmp_cache_t *b) / I - Second cache entry */
{

• return (a->address.ipv4.sin_addr.s_addr - b->address.ipv4.sin_addr.s_addr);
• return (strcasecmp(a->addrname, b->addrname));
  }

@@ -1874,8 +1874,8 @@

• Find a matching device in the cache...
  */
• key.address = addr;
• device = (snmp_cache_t *)cupsArrayFind(Devices, &key);
• key.addrname = addrname;
• device = (snmp_cache_t *)cupsArrayFind(Devices, &key);

/*

• Process the message...