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Re: [Qemu-block] [Qemu-devel] [PATCH] qemu-io: fix EOF Ctrl-D handling i
From: |
Daniel P. Berrange |
Subject: |
Re: [Qemu-block] [Qemu-devel] [PATCH] qemu-io: fix EOF Ctrl-D handling in qemu-io readline code |
Date: |
Wed, 6 Dec 2017 14:25:13 +0000 |
User-agent: |
Mutt/1.9.1 (2017-09-22) |
On Wed, Dec 06, 2017 at 08:22:35AM -0600, Eric Blake wrote:
> On 12/06/2017 05:57 AM, Daniel P. Berrange wrote:
> > qemu-io puts the TTY into non-canonical mode, which means no EOF processing
> > is
> > done and thus getchar() will never return the EOF constant. Instead we have
> > to
> > check for an explicit Ctrl-D, aka 0x4, to detect EOF and exit the qemu-io
> > shell. This fixes the regression that prevented Ctrl-D from triggering an
> > exit
> > of qemu-io that has existed since readline was first added in
> >
> > commit 0cf17e181798063c3824c8200ba46f25f54faa1a
> > Author: Stefan Hajnoczi <address@hidden>
> > Date: Thu Nov 14 11:54:17 2013 +0100
> >
> > qemu-io: use readline.c
> >
> > Signed-off-by: Daniel P. Berrange <address@hidden>
> > ---
> > qemu-io.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
>
> > while (!line) {
> > int ch = getchar();
> > - if (ch == EOF) {
> > + /* In non-canon tty mode we get 0x4 (Ctrl-D), not the stdio "EOF"
> > + * constant */
> > + if (ch == 0x4) {
>
> Should we instead be looking for a match against the current termios()
> c_cc[VEOF] setting, in case the user prefers something other than ^D via
> stty? Does readline provide any functionality for automating this?
I was afraid someone was going to suggest doing that. I was being lazy by
hardcoding Ctrl-D, but yes the real readline() library will honour the
VEOF value. QEMU though is using a home-grown reimpl of readline...
Regards,
Daniel
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