kermit doesn't wait long enough

Question

I'm writing a kermit script to start an elf on an IMX board running a custom kernel and I'm trying to capture a string written by the elf, with the following script:

set input echo on
lineout tests_domains/usb/hid/build/test  # send elf name to the board's shell
minput 40 "<--- PNC TEST STATUS: PASS" "<--- PNC TEST STATUS: INCONCLUSIVE" "<--- PNC TEST STATUS: FAIL" "<--- PNC TEST STATUS: NOTRUN" "<--- PNC TEST STATUS: TIMEOUT"
switch \v(minput) {
  :1, echo "TEST PASS", exit 0
  :2, echo "TEST INCONCLUSIVE", exit 1
  :3, echo "TEST FAIL", exit 2
  :4, echo "TEST NOTRUN", exit 3
  :5, echo "TEST TIMEOUT", exit 4
  :default, echo "entering default case", echo \v(minput), exit 255
}

However minput returns before having received one of the <--- PNC TESTS STATUS string and before 40 seconds. It returns circa 5~6 seconds after having launched the elf.

The full output of the board on its uart is as follows: https://pastebin.com/vsps5ZQ1 It ends up correctly with <--- PNC TEST STATUS: PASS

Whereas when capturing the output with the script above, it terminates as follows: https://pastebin.com/wFSDdn5s Output shows that the default case of the switch is executed, after having captured the string "0". It always return after a string of the form [ 6.099262][usbd:imx ] prime_endpoint: IN endpoint 1 (3) (last line written by the board in the second paste). I don't understand why the latter happens.

If there are alternatives to kermit to perform what I'm doing, please propose them to me. Online documentation for kermit is sparse.

Final note: ny kermit startup script (~/.kermrc) is as follows:

set line /dev/ttyUSB0
set speed 115200
set carrier-watch off
set handshake none
set flow-control none
robust
set file type bin
set file name lit
set rec pack 1000
set send pack 1000
set window 5

Dario · Accepted Answer · 2019-01-11T05:27:11.257

\v(minput) expands to the index of the received string, and indexing is zero-based. This means that you should have written

minput 40 "<--- PNC TEST STATUS: PASS" "<--- PNC TEST STATUS: INCONCLUSIVE" "<--- PNC TEST STATUS: FAIL" "<--- PNC TEST STATUS: NOTRUN" "<--- PNC TEST STATUS: TIMEOUT"
switch \v(minput) {
  :0, echo "TEST PASS", exit 0
  :1, echo "TEST INCONCLUSIVE", exit 1
  :2, echo "TEST FAIL", exit 2
  :3, echo "TEST NOTRUN", exit 3
  :4, echo "TEST TIMEOUT", exit 4
  :default, echo "entering default case", echo \v(minput), exit 255
}

What happens with your code is that, upon receiving <--- PNC TEST STATUS: PASS, minput exits with \v(minput) set to 0 and the switch only matches the default. The 0 in your output is not the string being received, it is its index as given to minput.

Thanks! I had inferred minput's behavior from an example script where the switch first case was :1, hence my mistake. It's working fine now. For the record I had tried emulating the kermit's script with pyserial, to no avail, the communication was brittle (I was witnessing garbage after writing (the text after lineout in the kermit script) to the serial port). — Clément Hurlin, Jan 11 '19 at 10:00

kermit doesn't wait long enough

1 Answers1