Re: [Sbcl-devel] failure to recognize /proc pipes as readable files

[Stas B. <sta...@gm...>]

Eric Schulte <sch...@gm...> writes:

> SBCL build with the attached patch fixes this bug on my system.
>
>
>>From 940504fb930ad823cfdf9cf8061fda49a4efaecb Mon Sep 17 00:00:00 2001
> From: Eric Schulte <sch...@gm...>
> Date: Thu, 22 Aug 2013 09:32:01 -0600
> Subject: [PATCH] use readlink to find pipe files when realpath fails
>
>   The fix only impacts runtime behavior when the call to realpath fails
>   to find an existing file.  In this case before failing readlink is
>   called, and if a pipe is found in the file location, then the location
>   of the original file is returned by (query-file-system * :truename).
>
>   With this change `open' may be called on pipe file handles.  This
>   fixes errors trying to read from /proc/self/fd/* file handles on Linux
>   systems, e.g. as generated by command line redirects.
This (string= (subseq (sb!unix:unix-readlink filename) 0 4) "pipe")
is both wasteful (copying the sequence) and incorrect (if the string
length is less than 4).
(and (>= (length string) 4) (string= string "pipe" :end1 4)) solves
this.

-- 
With best regards, Stas.