FreeBSD, setting the speed of a TERMIOS terminal is done using the ispeed and
ospeed options.
But when using simultaneously ispeed and ospeed parameters with SOCAT, the speed
values are set within two distinct ioctl requests, so changing the speed of
terminals or devices that need matching input and output returns an Invalid
argument error (the TIOCSETA/TIOCSETAW/TIOCSETAF ioctl returns -1 and sets errno
to EINVAL).
This is especially the case On FreeBSD, where many tty device drivers need
matching input and output speeds: - those that depend on ucom(4): uark(4),
ubsa(4), ubser(4), uftdi(4), umcs(4), uplcom(4), uslcom(4), uvscom(4) - some
others, even not depending on ucom(4): sio(4), digi(4), rp(4) But some don't:
tty(4)
With those drivers, the input and output speeds must match and be set inside a
single ioctl request (TIOCSETA, TIOCSETAW or TIOCSETAF). The only exception to
this rule is when the input baud rate is zero because, according to POSIX, in
that case, the input baud rate is set equal to the output baud rate.
For instance, this call to SOCAT on FreeBSD 10.1 terminates immediately with an
EINVAL error: # socat -d /dev/cuaU2,ispeed=57600,ospeed=57600,echo=0,raw
TCP-LISTEN:9000,reuseaddr 2015/03/09 00:43:33 socat[20723] E tcsetattr(3,
TCSADRAIN, 0x7fffffffe148): Invalid argument
Provide a patch that avoids this type of error: when setting both input and
output speeds, only one ioctl syscall is performed.
PR: 198441
Submitted by: Alexandre Fenyo <fbsd.bugzilla@fenyo.net>
811ac916cf