bug#1688: 23.0.60; ttname returned by system-process-attributes points to nonexisting file

[Stefan Monnier <monnier@iro.umontreal.ca>]

>> It's a good heursitic, but it's still just a heuristic.
>> You may have a /dev/tty directory and still use /dev/tty1.
>> Maybe it's better to get rid of the "/dev/" prefix to make it more clear
>> that it's not really a valid file name.
> you mean /dev/tty1 and /dev/tty/1 will exist at the same time?

No, I mean both /dev/tty1 being the device you want and /dev/tty being
a directory.  Rather than ISDIR you could indeed just check which of
/dev/tty1 and /dev/tty/1 exists and if only one exists then you should
be pretty sure which answer is the right one.  If they both exist (or
if neither exists), it's much less clear what to do.

> It won't as I know in Linux

That depends on the dev layout chosen by the distribution/user/...
I.e. it's a heuristic.

> procfs_ttyname should return a full path of the ttyname, or at least
> one function can return the fullpath.

Why?


        Stefan