From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Bowler Subject: Re: extra slash in current path Date: Thu, 23 Jun 2011 10:27:06 -0400 Message-ID: <20110623142706.GA13310@elliptictech.com> References: <20110623153116.404f2a63.taeuber@bbaw.de> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: yuyichao-mit Cc: richard -rw- weinberger , Lars =?iso-8859-1?Q?T=E4uber?= , linux-kernel@vger.kernel.org, linux-c-programming@vger.kernel.org On 2011-06-23 10:11 -0400, yuyichao-mit wrote: > On Thu, Jun 23, 2011 at 9:54 AM, richard -rw- weinberger > > Is this really a kernel issue? > > rw@raccoon:~> cd // > > rw@raccoon://> pwd > > // > > rw@raccoon://> ls -l /proc/self/cwd > > lrwxrwxrwx 1 rw users 0 23. Jun 15:53 /proc/self/cwd -> / > > well, that's true, but this is indeed the retrun value of get_current_dir_name. glibc's get_current_dir_name will honour the PWD environment variable in some cases, which is where the // actually comes from (i.e., it does not come from the kernel). This funny behaviour of cd is actually specified by POSIX (man 1p cd): 8. The curpath value shall then be converted to canonical form as follows, considering each component from beginning to end, in sequence: [...] c. An implementation may further simplify curpath by removing any trailing slash characters that are not also leading slashes, replacing multiple non-leading consecutive slashes with a single slash, and replacing three or more leading slashes with a single slash. If, as a result of this canonicalization, the curpath variable is null, no further steps shall be taken. 9. [...] The PWD environment variable shall be set to curpath. Cheers, -- Nick Bowler, Elliptic Technologies (http://www.elliptictech.com/)