On Tue, Oct 17, 2023 at 07:15:50PM +0900, Masahiro Yamada wrote: > > > > > > 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. Even if the distro does not match it will likely work to configure SRPM for non-matching distro and then build it on the target distro but I have not tested it. > > 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 That's basically the same thing as the patch that has been rejected. I used := to prevent calling pkg-config every time MODLIB is used but it might not be the most flexible wrt overrides. > 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. However, I can easily imagine a distribution that would want to put modules in /usr/lib-amd64-linux/modules. > 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. Yes, that's the semantics of the tool. The jq version was slightly less convoluted but required additional tool for building the kernel. > I do not know why you parsed kmod.pc instead of libkmod.pc [2] Because it's kmod property, not libkmod property. Distributions would install libkmod.pc only with development files whereas the kmod.pc should be installed with the binaries. Thanks Michal > > > [1] https://lore.kernel.org/linux-kbuild/20230718120348.383-1-msuchanek@xxxxxxx/ > [2] https://github.com/kmod-project/kmod/blob/v31/configure.ac#L295
