Shell: When shellGetLine fails the last line cmd is executed again Topic is solved

[Mbroek635]

Hello,

I'm using ChibiOS 21.11 on an STM32L496.
I'm using the serial_usb module to create a virtual com port over USB.
This virtual com port is used as the BaseSequentialStream for the shell.
When a certain command is entered the serial USB device is disabled and the USB is used for a mass storage device.
Let's call this command 'do_switch_msd'.
When the MSD is ejected the serial USB device is started again.

I noticed that when the USB device is disabled, the shell executes the 'do_switch_msd' command is called again.
After closer inspection I've noticed that:

• When shellGetLine fails (due to the stream being closed), and
• SHELL_CMD_EXIT_ENABLED is FALSE

the line variable will be interpreted again. This causes my 'do_switch_msd' function to be called again.

Here's a diff of how I'd solve this issue:

Code: Select all

diff --git a/os/various/shell/shell.c b/os/various/shell/shell.c
index a7cd30849..62594223f 100644
--- a/os/various/shell/shell.c
+++ b/os/various/shell/shell.c
@@ -375,6 +375,7 @@ THD_FUNCTION(shellThread, p) {
       /* Putting a delay in order to avoid an endless loop trying to read
          an unavailable stream.*/
       osalThreadSleepMilliseconds(100);
+      continue;
 #endif
     }
     lp = parse_arguments(line, &tokp);


I don't know if anyone or anything is counting on this behavior, but I consider this a bug.

Cheers

[Giovanni]

Hi,

Thanks, I will look into this.

Giovanni

[FXCoder]

In my modified version of shell.c i have this...

Code: Select all

#else
      /* Putting a delay in order to avoid an endless loop trying to read
         an unavailable stream.*/
      osalThreadSleepMilliseconds(100);
#endif
    }
    if (*line == 0)
      continue;
    lp = parse_arguments(line, &tokp);
   

And at the end of ShellGetLine(...) this...

Code: Select all

    if (c < 0x20)
      continue;
    if (p < line + size - 1) {
      streamPut(chp, c);
      *p++ = (char)c;
    }
    else {
      /* Input buffer overflow. Discard input line. Get new prompt. */
      *line = 0;
      chprintf(chp, SHELL_INPUT_ERROR_ALERT);
      return false;
    }
   

--
Bob

[Giovanni]

Hi,

Added that "continue", not doing other changes because the shell needs a global rework, better implement new behaviors in that context.

Giovanni