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Date:   Wed, 18 Oct 2023 03:25:19 +0200 (CEST)
From:   Jan Engelhardt <jengelh@inai.de>
To:     Lucas De Marchi <lucas.demarchi@intel.com>
cc:     Michal Suchanek <msuchanek@suse.de>, linux-modules@vger.kernel.org,
        Takashi Iwai <tiwai@suse.com>,
        Lucas De Marchi <lucas.de.marchi@gmail.com>,
        =?UTF-8?Q?Michal_Koutn=C3=BD?= <mkoutny@suse.com>,
        Jiri Slaby <jslaby@suse.com>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Nicolas Schier <nicolas@fjasle.eu>,
        linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH kmod v5 5/5] libkmod, depmod, modprobe: Make directory
 for kernel modules configurable
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On Tuesday 2023-10-17 19:50, Lucas De Marchi wrote:
>> +AC_ARG_WITH([module_directory],
>> +        AS_HELP_STRING([--with-module-directory=DIR], [directory in which to
>> look for kernel modules - typically '/lib/modules' or
>> '${prefix}/lib/modules']),
>> +        [], [with_module_directory=/lib/modules])
>> +AC_SUBST([module_directory], [$with_module_directory])
>
> we will probably have "fun" results if we accept a relative path here.

$ ./configure --prefix=/usr --bindir=../bin
configure: error: expected an absolute directory name for --bindir: ../bin

While such check does not exist for --with-module-directory, everyone
has likely been well-trained not to use relative paths. Even if, say,
cmake/meson *could* do it, it just would have never occurred to me to
actually *utilize* it, because it is just too ambiguous and
potentially dangerous.

Just think of all the fun you could have with LD_LIBRARY_PATH=".."