kern/163076: It is not possible to read in chunks from linprocfs and procfs.

[Jaakko Heinonen]

The following reply was made to PR kern/163076; it has been noted by GNATS.

From: Jaakko Heinonen <jh at FreeBSD.org>
To: Petr Salinger <Petr.Salinger at seznam.cz>
Cc: bug-followup at FreeBSD.org, phk at FreeBSD.org
Subject: Re: kern/163076: It is not possible to read in chunks from linprocfs
 and procfs.
Date: Mon, 5 Dec 2011 16:49:47 +0200

 Hi,
 
 On 2011-12-05, Petr Salinger wrote:
 > It is not possible to read in chunks from linprocfs and procfs.
 > It is a regression against stable-8.
 > I suspect it is due to changes of sbuf implementation between 8 and 9.
 
 Yes, r222004 changed sbuf_finish() to not clear s->s_error which causes
 the regression. I am not sure if we should blame r222004 or the pseudofs
 code.
 
 I have Cc'd the committer of r222004.
 
 > Some files are rather big (over 4KB) and it is really standard to read them in blocks.
 > >How-To-Repeat:
 > "dd if=$FILE bs=1", with FILE any file in procfs or linprocfs
 > The result is empty output.
 > 
 > Tried with FILE /proc/version from linprocfs 
 > and /proc/curproc/map from procfs. 
 > 
 > For more details see Debian GNU/kFreeBSD bug report 
 > http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=650667
 
 -- 
 Jaakko