> > > > Let me add more context to my question. > > > > > > I am interested in the timing when > > 'pkg-config --print-variables kmod | grep module_directory' > > is executed. > > > > > > > > 1. Build a SRPM on machine A > > > > 2. Copy the SRPM from machine A to machine B > > > > 3. Run rpmbuild on machine B to build the SRPM into a RPM > > > > 4. Copy the RPM from machine B to machine C > > > > 5. Install the RPM to machine C > > As far as I am aware the typical use case is two step: > > 1. run make rpm-pkg on machine A > 2. install the binary rpm on machine C that might not have build tools > or powerful enough CPU > > While it's theoretically possible to use the srpm to rebuild the binary > rpm independently of the kernel git tree I am not aware of people > commonly doing this. If I correctly understand commit 8818039f959b2efc0d6f2cb101f8061332f0c77e, those Redhat guys pack a SRPM on a local machine, then send it to their build server called 'koji'. Otherwise, there is no reason to have 'make srcrpm-pkg'. I believe "A == B" is not always true, but we can assume "distro(A) == distro(B)" is always met for simplicity. So, I am OK with configuration at the SRPM time. > If rebuilding the source rpm on a different machine from where the git > tree is located, and possibly on a different distribution is desirable > then the detection of the KERNEL_MODULE_DIRECTORY should be added in the > rpm spec file as well. > > > Of course, we are most interested in the module path > > of machine C, but it is difficult/impossible to > > guess it at the time of building. > > > > We can assume machine B == machine C. > > > > We are the second most interested in the module > > path on machine B. > > > > The module path of machine A is not important. > > > > So, I am asking where you would inject > > 'pkg-config --print-variables kmod | grep module_directory'. > > I don't. I don't think there will be a separate machine B. > > And I can't really either - so far any attempt at adding support for > this has been rejected. > > Technically the KERNEL_MODULE_DIRECTORY could be set in two steps - one > giving the script to run, and one running it, and then it could be run > independently in the SRPM as well. At first, I thought your patch [1] was very ugly, but I do not think it is so ugly if cleanly implemented. It won't hurt to allow users to specify the middle part of MODLIB. There are two options. [A] Add 'MOD_PREFIX' to specify the middle part of MODLIB The top Makefile will look as follows: MODLIB = $(INSTALL_MOD_PATH)$(MOD_PREFIX)/lib/modules/$(KERNELRELEASE) export MODLIB It is easier than specifying the entire MODLIB, but you still need to manually pass "MOD_PREFIX=/usr" from an env variable or the command line. If MOD_PREFIX is not given, MODLIB is the same as the current one. [B] Support a dynamic configuration as well MOD_PREFIX ?= $(shell pkg-config --variable=module_prefix libkmod 2>/dev/null) export MOD_PREFIX MODLIB = $(INSTALL_MOD_PATH)$(MOD_PREFIX)/lib/modules/$(KERNELRELEASE) export MODLIB If MOD_PREFIX is given from an env variable or from the command line, it is respected. If "pkg-config --variable=module_prefix libkmod" works, that configuration is applied. Otherwise, MOD_PREFIX is empty, i.e. fall back to the current behavior. I prefer 'MOD_PREFIX' to 'KERNEL_MODULE_DIRECTORY' in your patch [1] because "|| echo /lib/modules" can be omitted. I do not think we will have such a crazy distro that installs modules under /opt/ directory. I could not understand why you inserted "--print-variables kmod 2>/dev/null | grep '^module_directory$$' >/dev/null" but I guess the reason is the same. "pkg-config --variable=module_directory kmod" always succeeds, so "|| echo /lib/modules" is never processed. I do not know why you parsed kmod.pc instead of libkmod.pc [2] [1] https://lore.kernel.org/linux-kbuild/20230718120348.383-1-msuchanek@xxxxxxx/ [2] https://github.com/kmod-project/kmod/blob/v31/configure.ac#L295 -- Best Regards Masahiro Yamada
