misc/149335: shell script runs on Linux but not on freebsd

Oliver Fromme olli at lurza.secnetix.de
Fri Aug 6 07:20:04 UTC 2010


The following reply was made to PR misc/149335; it has been noted by GNATS.

From: Oliver Fromme <olli at lurza.secnetix.de>
To: eb30750 at gmail.com, freebsd-bugs at FreeBSD.ORG, bug-followup at FreeBSD.ORG
Cc:  
Subject: Re: misc/149335: shell script runs on Linux but not on freebsd
Date: Fri, 6 Aug 2010 09:12:40 +0200 (CEST)

 Paul Lambert wrote:
  > > Number:         149335
  > > Category:       misc
  > > Synopsis:       shell script runs on Linux but not on freebsd
  > [...]
  > > Environment:
  > FreeBSD BRSINC-VM02.local 8.1-RELEASE FreeBSD 8.1-RELEASE #0: Mon Jul 19 02:36:49 UTC 2010     root at mason.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC  amd64
  > > Description:
  > The script fails on these two lines so far; "stat" and "od"
  > 
  > # This won't work with non-GNU stat.
  > FILE_SIZE=`stat --format "%s" "$0"`
  > offset=$(($FILE_SIZE - 4))
 
 As the comment suggests, that command is non-portable and
 works with GNU stat (linux) only.  This is not a standard.
 The equivalent BSD command line would be:
 
 FILE_SIZE=`stat -f %z "$0"`
 
 I wonder why the script even needs to find out its own size,
 and then read binary data from itself?!?  Is this some kind
 of "copy protection" or similar tricks?  If so, I suspect
 that it is highly non-portable and will be difficult to get
 to run on anything else than linux.
 
  >    # XXX: put extraction in its own function
  >    MAGIC_NUMBER=`od -An -t u4 -N 4 -j $MAGIC_OFFSET "$file" | tr -d ' '`
 
 This command works fine on FreeBSD 8.1.  If it doesn't work
 in the context of the script, I suspect that it is caused
 by preceding problems that set one of the variables to a
 wrong value.
 
 As a work-around, you might try running the script with
 /compat/linux/bin/sh instead of /bin/sh.  You need to
 enable Linux compatibility ("kldload linux") and install
 ports/emulators/linux_base-f10 if you don't have it already.
 
 As this is not a bug in FreeBSD, I suggest that this PR can
 be closed.  Do you agree?
 
 Best regards
    Oliver
 
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