[BUG] M33 ("Get Long Path") crashes firmware if no parameter provided

[theomega]

Did you test the latest bugfix-2.0.x code?

Yes, and the problem still exists.

Bug Description

The M33 command, according to the documentation requires a parameter. If this parameter is provided, the command works fine.

BUT: If you forget the provide the parameter, the firmware crashes.

This seems to be a null pointer the source code assumes that the parameter is there and then most likely crashes.

Bug Timeline

Should have been the case since the M33 Command was introduced.

Expected behavior

Error message is printed.

Actual behavior

Firmware crashes

Steps to Reproduce

1. Have your firmware compiled with LONG_FILENAME_HOST_SUPPORT (otherwise, there is no M33 command)
2. Execute M33

Version of Marlin Firmware

2.0.8

Printer model

Home Built

Electronics

FYSETC E4 board, based on ESP32

Add-ons

No response

Your Slicer

No response

Host Software

No response

Additional information & file uploads

No response

[XDA-Bam]

Is something like

void GcodeSuite::M33() {

  if(parser.string_arg)
    card.printLongPath(parser.string_arg);
  else
    SERIAL_ECHOLNPGM(STR_SD_CANT_OPEN_SUBDIR);

}

enough? Or do we need to define a new warning message?

[charlespick]

Is something like

void GcodeSuite::M33() {

  if(parser.string_arg)
    card.printLongPath(parser.string_arg);
  else
    SERIAL_ECHOLNPGM(STR_SD_CANT_OPEN_SUBDIR);

}

enough? Or do we need to define a new warning message?

Looks like it's worth testing!

[github-actions]

This issue has had no activity in the last 60 days. Please add a reply if you want to keep this issue active, otherwise it will be automatically closed within 10 days.

[XDA-Bam]

Bad bot. I know how to fix it, but didn't get to it yet. Please keep this open.

[thisiskeithb]

I cannot replicate the crashing using today's bugfix-2.0.x (3fdf40f), so please download a fresh copy of bugfix-2.0.x to test with the latest code and let us know if you're still having this issue.

[sjasonsmith]

This crash is now eliminated, by eliminating a strlen call with a NULL pointer. It does not print any error message, just a blank line of output for the "long" filename. There could be other ways to resolve this (as discussed above), but since this is an incorrect use-case anyway, I think that just preventing crashing should be good enough.

[github-actions]

This issue has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.