The cmd_exit() function used -EINTR to signal a clean exit from the
interactive mode. This is semantically incorrect because EINTR is an
errno value meant for system call interruptions, not application-level
control flow.
Stop using -EINTR for cmd_exit(). Introduce ISOBUSFS_CLI_RET_EXIT (a
positive return code) to distinguish control flow from actual errors.
Map this to exit code 0 in main(), keeping negative errno values for
real errors. This makes the exit path explicit and prevents confusion
with actual interrupted system calls.
Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>
a5bd791999