Date: Fri, 27 Feb 2009 23:56:30 GMT From: Jan Schaumann <jschauma@netmeister.org> To: freebsd-gnats-submit@FreeBSD.org Subject: misc/132182: uname(1) uses UNAME_<flag> variables even if those are empty Message-ID: <200902272356.n1RNuUTL007368@www.freebsd.org> Resent-Message-ID: <200902280000.n1S00CDg047422@freefall.freebsd.org>
next in thread | raw e-mail | index | archive | help
>Number: 132182 >Category: misc >Synopsis: uname(1) uses UNAME_<flag> variables even if those are empty >Confidential: no >Severity: non-critical >Priority: low >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Sat Feb 28 00:00:12 UTC 2009 >Closed-Date: >Last-Modified: >Originator: Jan Schaumann >Release: >Organization: >Environment: >Description: uname(1) on FreeBSD has the interesting feature that one can set, say, UNAME_r to a string and 'uname -r' will report that string. However, it will also report that string if UNAME_r is set in the environment but empty. I believe that is a bug, since the intention is to use the UNAME_r variable as specified by the user, but the user may wish to change this back to the default. Yes, this can be worked around by using 'unset'; however, in some instances this isn't possible: consider a crontab where an entry needs to execute using the variable, but other crontabs must not: UNAME_r=foo 0 * * * * whatever UNAME_r= * * * * * another Using 'unset' is not an option in this scenario, nor is "remembering" the previous value in a temporary variable a la "UNAME_r_orig=$(uname -r)". >How-To-Repeat: export UNAME_r="foo" uname -r export UNAME_r= uname -r >Fix: diff -b -u -r1.14 uname.c --- uname.c 1 Jul 2003 20:15:28 -0000 1.14 +++ uname.c 27 Feb 2009 23:52:52 -0000 @@ -134,7 +134,8 @@ #define CHECK_ENV(opt,var) \ do { \ - if ((var = getenv("UNAME_" opt)) == NULL) { \ + if (((var = getenv("UNAME_" opt)) == NULL) || \ + (strlen(var) == 0)) { \ get_##var = native_##var; \ } else { \ get_##var = (get_t)NULL; \ >Release-Note: >Audit-Trail: >Unformatted:
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200902272356.n1RNuUTL007368>