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From: Bart Schaefer <schaefer@brasslantern.com>
To: Branden Archer <brarcher@lexmark.com>, zsh-workers@zsh.org
Subject: Re: Issue with resolving paths with zsh using \0 in variables
Date: Wed, 14 Jun 2017 16:02:24 -0700	[thread overview]
Message-ID: <170614160224.ZM20305@torch.brasslantern.com> (raw)
In-Reply-To: <CAADoZg3dsdn6yBrkUYQj3=w6ZKyqQDu5sG+kEas9c5yLNU1XPA@mail.gmail.com>

On Jun 13,  3:32pm, Branden Archer wrote:
}
} This is an issue found when attempting to use paths in zsh where
} parts of the path are taken from data on the /sys filesystem. Namely,
} when cat'ing a file from the /sys filesystem it may return some data
} with a \0 at the end. If that variable is used to form a path the \0
} interferes with the path resolution.

I believe this is because zsh supports having nul-bytes in parameter
values, whereas bash treats the nul as terminating the string.  This
is not something we can (or I think want) to special-case for file
paths.

Those files in /sys are documented to contain strings separated by
nul bytes, so as soon as you read one with "cat" you have already
made a coding error.  Instead you should be doing something like

    read -d $'\0' -E < location

Conversely, this --

} root~# echo "hi" > sub$(cat location)/myfile
} zsh: is a directory: subdir

-- probably is a bug, just not the bug you think it is; the error should
be that "subdir\0" is an illegal file name, rather than terminating the
path at the nul and botching the redirection.


  parent reply	other threads:[~2017-06-14 23:01 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-13 19:32 Branden Archer
2017-06-14  0:38 ` Eric Cook
2017-06-14 23:02 ` Bart Schaefer [this message]
2017-06-15  3:40   ` Eric Cook
2017-06-15  4:13     ` Bart Schaefer
2017-06-15  4:22     ` Bart Schaefer

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