stty: drop incorrect flags for apple target

[oech3]

https://github.com/apple-oss-distributions/xnu/blob/f6217f891ac0bb64f3d375211650a4c1ff8ca1ea/bsd/sys/termios.h#L149

nix seems accidentaly exposing them. Noted at bytecodealliance/rustix#1706 (comment) .

[oech3]

I don't like diff given by cargo fmt.

[xtqqczze]

$ rustc --print host-tuple                                                   
aarch64-apple-darwin
$ cargo run -q --features unix stty --all

Diff from this change:

@@ -5,6 +5,6 @@ discard = ^O; min = 1; time = 0;
 -parenb -parodd cs8 hupcl -cstopb cread -clocal -crtscts
 -ignbrk brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl -ixoff -tandem
 ixon ixany imaxbel iutf8
-opost -ocrnl onlcr -onocr -onlret -ofdel nl0 cr0 tab0 bs0 vt0 ff0
+opost -ocrnl onlcr -onocr -onlret
 isig icanon iexten echo echoe echok -echonl -noflsh -tostop -echoprt echoctl
 echoke -flusho -extproc

[xtqqczze]

@collinfunk GNU stty output includes -ofdel nl0 cr0 tab0 bs0 vt0 ff0 flags for Apple targets, but the Apple headers state:

The following block of features is unimplemented. Use of these flags in programs will currently result in unexpected behaviour.

[oech3]

I think kernel should reject them with EINVAL even if it was given to kernel. Should GNU remove them too?
I think those flags are useful to share --all's output as config with different platforms.
@pixelb

[oech3]

This is probably why nix crate expose them...

[xtqqczze]

These are all flags required by POSIX, so I'm not sure we should exclude them even Apple does not implement them:

https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/termios.h.html

[oech3]

I think we can drop them if they are bottom of struct.

[oech3]

One of an another reason for removing them is compatibility with stty installed on macOS by default.

[xtqqczze]

It seems macOS stty does not error with flags such as ofdel (but does with olcuc).

$ stty ofdel
$ stty nl0
$ stty cr0
$ stty tab0
$ stty bs0
$ stty vt0
$ stty ff0
$ stty olcuc
stty: illegal option -- olcuc
usage: stty [-a | -e | -g] [-f file] [arguments]

So I think we should not make this change.

[xtqqczze]

@oech3 Should nix-rust/nix#2846 be closed?

[oech3]

Sure

[xtqqczze]

@oech3 For bytecodealliance/rustix#1706, does rustix lack support for any flags on Apple targets?

[oech3]

I think we can edit issue title to request unimplemented flags. But I think usecase is too nich to request.

[xtqqczze]

Which specific flags are unimplemented in rustix for Apple targets?

[oech3]

Same with flags this PR tried to drop?

[oech3]

Oh... rustix expose some unimplemented flags e.g. OCRNL... So for consistency, we should request to add them...

[oech3]

Do we need to support unimplemented flags also on other BSDs?

[xtqqczze]

Same with flags this PR tried to drop?

So your claim is rustix does not support the following flags for Apple targets?

• ofdel
• nl0
• cr0
• tab0
• bs0
• vt0
• ff0

[oech3]

Yes.

[oech3]

Sorry. TAB0 is given.

[xtqqczze]

Do we need to support unimplemented flags also on other BSDs?

If they are POSIX I would think so.

https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/termios.h.html

[xtqqczze]

I've addressed the missing flags for Apple targets upstream in bytecodealliance/rustix#1709.

[xtqqczze]

Do we need to support unimplemented flags also on other BSDs?

Since they are not implemented in libc crate for other BSDs, nothing we can do for now.

[oech3]

On FreeBSD CI:

  script -q /dev/null gstty --all
  Warning: Permanently added '[127.0.0.1]:10022' (ED25519) to the list of known hosts.
  ^D��speed 9600 baud; rows 0; columns 0;
  intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = <undef>;
  eol2 = <undef>; start = ^Q; stop = ^S; susp = ^Z; dsusp = ^Y; rprnt = ^R;
  werase = ^W; lnext = ^V; discard = ^O; status = ^T; min = 1; time = 0;
  -parenb -parodd cs8 hupcl -cstopb cread -clocal -crtscts
  -ignbrk brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl ixon -ixoff
  ixany imaxbel iutf8
  opost -ocrnl onlcr -onocr -onlret tab0
  isig icanon iexten echo echoe -echok -echonl -noflsh -tostop -echoprt echoctl
  echoke -flusho -extproc

Failed to do same things on OpenBSD.

[xtqqczze]

So there is no issue for other BSD?

[oech3]

I think so. But stty under script command might change something.
@lcheylus @0323pin Would you share gnu-stty --all under *BSD?

[0323pin]

@oech3

On NetBSD

~> gnu-stty --all
Exception: exec: "gnu-stty": executable file not found in $PATH
~> stty --all
stty: illegal option -- --all
usage: stty [-a|-e|-g] [-f file] [operand ...]
Exception: stty exited with 1

https://man.netbsd.org/stty.1

[oech3]

My bad. Would you try gstty --all of coreutils package https://ftp.netbsd.org/pub/pkgsrc/current/pkgsrc/sysutils/coreutils/index.html ?

[lcheylus]

On OpenBSD current/amd64, with GNU coreutils installed via coreutils package.

$ gstty --all
speed 115200 baud; rows 67; columns 273;
intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = <undef>; eol2 = <undef>; start = ^Q; stop = ^S; susp = ^Z; dsusp = ^Y; rprnt = ^R; werase = ^W; lnext = ^V; discard = ^O; status = <undef>; min = 1; time = 0;
-parenb -parodd cs8 hupcl -cstopb cread -clocal -crtscts
-ignbrk brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl ixon -ixoff -iuclc ixany imaxbel
opost -olcuc -ocrnl onlcr -onocr -onlret tab0
isig icanon iexten echo echoe -echok -echonl -noflsh -xcase -tostop -echoprt echoctl echoke -flusho -extproc

[0323pin]

My bad. Would you try gstty --all of coreutils package https://ftp.netbsd.org/pub/pkgsrc/current/pkgsrc/sysutils/coreutils/index.html ?

Sure ... I had to build it because, I usually don't have it installed. Hence, the slight delay 😆

So, on NetBSD dev branch ...

gstty --all
speed 9600 baud; rows 44; columns 187;
intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = <undef>; eol2 = <undef>; start = ^Q; stop = ^S; susp = ^Z; dsusp = ^Y; rprnt = ^R; werase = ^W; lnext = ^V; discard = ^O;
status = ^T; min = 1; time = 0;
-parenb -parodd cs8 hupcl -cstopb cread -clocal -crtscts
-ignbrk brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl -ixon -ixoff ixany imaxbel
opost -ocrnl onlcr -onocr -onlret
isig icanon iexten echo echoe -echok -echonl -noflsh -tostop -echoprt echoctl echoke -flusho -extproc

[oech3]

Thankyou! So *BSD we don't need to fix *BSD.