From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <zsh-workers-return-36217-mason-zsh=primenet.com.au@zsh.org>
Received: (qmail 20611 invoked by alias); 18 Aug 2015 09:19:12 -0000
Mailing-List: contact zsh-workers-help@zsh.org; run by ezmlm
Precedence: bulk
X-No-Archive: yes
List-Id: Zsh Workers List <zsh-workers.zsh.org>
List-Post: <mailto:zsh-workers@zsh.org>
List-Help: <mailto:zsh-workers-help@zsh.org>
X-Seq: 36217
Received: (qmail 202 invoked from network); 18 Aug 2015 09:19:11 -0000
X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on f.primenet.com.au
X-Spam-Level: 
X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,DKIM_SIGNED,
	DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM autolearn=ham autolearn_force=no
	version=3.4.0
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=gmail.com; s=20120113;
        h=date:from:to:subject:message-id:mail-followup-to:mime-version
         :content-type:content-disposition:content-transfer-encoding
         :user-agent;
        bh=ljbzqRrkmGAYvV/tuXZILgltFWDqD2hjAa22eOjVLQY=;
        b=pYt2+7jyN4+JkQN/ZEUaVuLmpkxICGgA0zQW13cGn+Lg3HtPzMpQG01RPCB5lngLYW
         yH1jrh+N1016OlBlHHWaanbG+wLVh7Kjd8oX03150HSB621GdDW8TXyZ4XIgq/OGSGj+
         ipvrbDr6T1Su58c2T80fmWcIfCyvWl4xaWZtkGUKWY9NBXSDl1kEyIgaJ+440Y0MF+tJ
         pIeyzZ2NYVtVgsPE9jW9yuc6SUjiwlJ+ft4dwxzlQ8+A+OxuY+X5Elfq1y8zTSaXV5R3
         Rn49jIaZpwAih0i677xiOBO/BHWteA6TumRK1y9CHYRqCGSGBwUHMEKMfcR3Su6jXDtI
         CWBg==
X-Received: by 10.194.204.163 with SMTP id kz3mr11522768wjc.28.1439889546408;
        Tue, 18 Aug 2015 02:19:06 -0700 (PDT)
Date: Tue, 18 Aug 2015 10:19:04 +0100
From: Stephane Chazelas <stephane.chazelas@gmail.com>
To: Zsh hackers list <zsh-workers@zsh.org>
Subject: mkdir builtin and $'\0'
Message-ID: <20150818091904.GA5389@chaz.gmail.com>
Mail-Followup-To: Zsh hackers list <zsh-workers@zsh.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
User-Agent: Mutt/1.5.21 (2010-09-15)

$ zsh --version
zsh 5.0.8 (x86_64-pc-linux-gnu)
$ strace -e mkdir zsh -c "zmodload zsh/files; mkdir $'a\0b'"
mkdir("a\203 b", 0755)                  = -1 EEXIST (File exists)
zsh:mkdir:1: cannot make directory `a^@b': file exists
+++ exited with 1 +++

See how that $'\0' became "\203 " except in the error message.

Not a big problem in that nothing good will ever come out of
mkdir $'\0' anyway since one can't pass a NUL character to the
mkdir() system call.

A bit worse:

$ strace -e chdir zsh -c "cd $'a\0b'; print -r -- \$PWD; pwd"
chdir("/export/home/stephane/a")        = -1 ENOENT (No such file or directory)
chdir("a\203 b")                        = 0
chdir("..")                             = 0
chdir("..")                             = 0
chdir("..")                             = 0
chdir("/home/stephane/a\203 b")         = 0
/export/home/stephane/a
/home/stephane/a� b
+++ exited with 0 +++

I suppose the chdir("..")s come after the realisation that $PWD
probably doesn't represent the current directory anymore (since
chdir("$PWD/dir") doesn't work while chdir("dir") does).

"mv" at least doesn't have the problem. A note though:

$ strace -e rename zsh -c "zmodload zsh/files; mv $'a\0b' x"
rename("a", "x/a")                      = -1 ENOENT (No such file or directory)
zsh:mv:1: a^@b: no such file or directory
+++ exited with 1 +++

The error message mentions a^@b not existing while it did
attempt to rename "a" instead.

Maybe those builtins should fail with an error if one attempts
to call them with an argument containing NUL.

-- 
Stephane