This reverts the change to is_interactive() by commit 80aed96286,
which switched it to using the new conio system. Now we're back to
doing it the same way as we used to: we check if stdin is a console.
The only use of is_interactive() on Windows is deciding whether to
present the console antispoof prompt. (On Unix it has an additional
use in cmdgen, for deciding whether to emit progress reports, but on
Windows that doesn't come up).
On Unix this is based on stdin being a tty, which means that a
command such as "plink host do stuff </dev/null" omits the antispoof
prompt. That's deliberate: the prompt is to defend against attacks
where the user sends interactive input to the SSH session channel
believing it to be directed at userauth, but if the input _isn't_
coming from the interactive terminal where the user is answering
userauth prompts, then they can't do that even if they are fooled.
On Windows, I think the same argument applies, now that we're reading
userauth prompts from the console in the same way as Unix. So
is_interactive() now does the analogous thing on Windows.
Conveniently, this _also_ means is_interactive() is back to exactly
how it was before the conio rewrite, which means it's one fewer thing
that can unexpectedly change and break someone's workflow. (Otherwise
I might also have wanted to change its behaviour based on
-legacy-stdio-handling, which would be extra ugly.)
PuTTY source code README
========================
This is the README for the source code of PuTTY, a free Windows and
Unix Telnet and SSH client.
PuTTY is built using CMake <https://cmake.org/>. To compile in the
simplest way (on any of Linux, Windows or Mac), the general method is
to run these commands in the source directory:
cmake .
cmake --build .
These commands will expect to find a usable compile toolchain on your
path. So if you're building on Windows with MSVC, you'll need to make
sure that the MSVC compiler (cl.exe) is on your path, by running one
of the 'vcvars32.bat' setup scripts provided with the tools. Then the
cmake commands above should work.
To install in the simplest way on Linux or Mac:
cmake --build . --target install
On Unix, pterm would like to be setuid or setgid, as appropriate, to
permit it to write records of user logins to /var/run/utmp and
/var/log/wtmp. (Of course it will not use this privilege for
anything else, and in particular it will drop all privileges before
starting up complex subsystems like GTK.) The cmake install step
doesn't attempt to add these privileges, so if you want user login
recording to work, you should manually ch{own,grp} and chmod the
pterm binary yourself after installation. If you don't do this,
pterm will still work, but not update the user login databases.
Documentation (in various formats including Windows Help and Unix
`man' pages) is built from the Halibut (`.but') files in the `doc'
subdirectory. If you aren't using one of our source snapshots,
you'll need to do this yourself. Halibut can be found at
<https://www.chiark.greenend.org.uk/~sgtatham/halibut/>.
The PuTTY home web site is
https://www.chiark.greenend.org.uk/~sgtatham/putty/
If you want to send bug reports or feature requests, please read the
Feedback section of the web site before doing so. Sending one-line
reports saying `it doesn't work' will waste your time as much as
ours.
See the file LICENCE for the licence conditions.
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