socat-1.7.3.3 (focal) termios options incorrectly applied to the second address

[Sascha Lucas]

Hi,

the socat version in Focal (1.7.3.3) breaks certain applications (i.e. qemu serial console), when using raw mode or disabling echo (required for serial consoles). Example: start socket in listening mode: "qemu-system-x86_64 -serial unix:/tmp/socket,server", connect with socat:

/usr/bin/socat -ddd STDIO,raw,echo=0,escape=0x1d UNIX-CONNECT:/tmp/socket
2020/06/17 17:08:19 socat[26254] I setting option "raw"
2020/06/17 17:08:19 socat[26254] I setting option "echo" to 0
2020/06/17 17:08:19 socat[26254] I setting option "escape" to 29
2020/06/17 17:08:19 socat[26254] N reading from and writing to stdio
2020/06/17 17:08:19 socat[26254] N opening connection to AF=1 "/tmp/socket"
2020/06/17 17:08:19 socat[26254] I socket(1, 1, 0) -> 5
2020/06/17 17:08:19 socat[26254] E tcsetattr(5, TCSADRAIN, 0x556ef9be59c0): Inappropriate ioctl for device
2020/06/17 17:08:19 socat[26254] N exit(1)
2020/06/17 17:08:19 socat[26254] I shutdown(5, 2)

According to the Changelog from socat-1.7.3.4[1] this is a know problem (Under certain circumstances, termios options of the first address were applied to the second address, resulting in error "Inappropriate ioctl for device"). The upstream commit[2] fixes this issue (also released in socat-1.7.3.4).

Thanks, Sascha.

[1] http://www.dest-unreach.org/socat/doc/CHANGES
[2] https://repo.or.cz/socat.git/commit/5ebf36038f3960798e769bff5646e755a91a1119

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.