On Apr 10 14:20, Eric Blake wrote: > On 04/10/2014 01:04 PM, Corinna Vinschen wrote: > > A local cygwin user told me that the users in their company would > > probably be confused by the '+ or, FWIW, any other non-backslash char, > > because they were drilled to see and use usernames always in domain\name > > form, or even in domain\\user form when logging in to Linux. > > > > I like slashes a lot more for obvious reasons. But maybe, and that > > wouldn't be too hard to implement, we could accept account names with > > slash and with backslash, just as we do with pathnames. Output of > > usernames would be with slashes, of course. > > POSIX says: > [...] > In short, in POSIX systems, user names are solely from the set > [-_.a-zA-Z0-9]; which excludes +, \, or any other separator we come up > with. I'm fine with using a non-portable character (this is, after all, > a cygwin extension of how to map Windows user names to a Linux emulation > environment). But keeping in mind the rules on tilde expansion, > > ~a+b/file > > can undergo tilde expansion for username 'a+b', but > > ~a\\b/file > > cannot do so, because the \ is necessarily always quoted. There is no > way to get tilde expansion to work for a username containing a shell > metacharacter, which frowns on quite a few otherwise useful characters, > including \. > > Worse, the thought of using / as the separator gives me the willies - it > is BOUND to go wrong. The expression > > ~a/b/file > > is NOT requesting 'file' within user 'a/b's home, but 'b/file' within > user 'a's home.
This is a really good point. This effectively eliminates slash from the picture and the backslash reduces usability a lot, it seems. So we might actually be better off by sticking to a configurable separator char and default '+'? What bugs me a bit is what this means for applications which expect fixed usernames. Sshd, for instance, expects the fixed username "sshd" right now when using privilege separation. I discussed this with the OpenSSH devs, and they understand the problem, but they think this should be handled by a Cygwin-specific function. So there's some extra work in it for me to get OpenSSH up to speed with this change, but I fear I'm not the only one. The more configurable stuff like this is, the more complicated it gets maintaining some packages. Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Maintainer cygwin AT cygwin DOT com Red Hat
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