kumquat-buildroot/package/eudev/Config.in.host

# Select this if you need host eudev tools (e.g. udevadm)
config BR2_PACKAGE_HOST_EUDEV
	bool
package/eudev: introduce a host variant eudev and systemd provide a hardware database (hwdb) as a set of multiple files. Various other utilities may also use that database. Those files have to be "compiled" into a binary to be useful; libudev (and thus all utilities based on it) only use the compiled hwdb. Compiling the hwdb is done with udevadm, using the hwdb sub-command: udevadm hwdb --update Provide a simple host-variant of eudev, so that we can call udevadm at build time. When it is configured, eudev will shoehorn its --prefix path as the base location where the .hwdb file will be searched from, as well as where the hwdb.bin will be generated in. This means that with the usual --prefix=$(HOST_DIR), it would look into there. udevadm also accepts a --root=/path option at runtime, which prepends /path to all the paths it uses to find and generate files. Obviously, combining --root=$(TARGET_DIR) and --prefix=$(HOST_DIR) would not do what we want: all files would be searched for, and generated, in $(HOST_DIR)$(TARGET_DIR)/ . Avoiding use of --root would not help much either, as files would still searched in $(HOST_DIR) (we could use a trick to copy files there, generate and then move the hwdb.bin, but that's not nice). However, since we only need udevadm, and since udevadm has no internal and no external dependency, we can use a less dirty trick and configure host-eudev with --prefix=/usr (and similar for the other paths), manually copy udevadm to HOST_DIR, and then use --root when calling it. Then, we get a udevadm that can read files from, and generate files into $(TARGET_DIR). We register a target-finalize hook to generate the hwdb.bin, so that any pakage may install its .hwdb files (currently only eudev and systemd do, but other packages might (e.g. sane is known to do so on standard desktop distros)) The *.hwdb source files consume a lot of space, roughly the same as the generated database, i.e. ~8MiB as of today, and they are totally useless on the target; only the generated hwdb.bin is useful. So we want to get rid of them. However, we also want to be able to complete a build (e.g. make foo-reinstall to reinstall more hwdb files), so we don't want to irremediably lose them. As such, we register a pre-rootfs-cmd hook, that removes them just before assembling the filesystems, when we're only using a copy of the target directory. Note that this is the first host package to register a target-finalize hook, and also the first to register a pre-rootfs-cmd hook. This avoids duplicating these hooks logic in both eudev and systemd. Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr> Cc: Peter Korsgaard <peter@korsgaard.com> Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com> Cc: Carlos Santos <unixmania@gmail.com> Signed-off-by: Peter Korsgaard <peter@korsgaard.com> 2019-10-29 23:07:53 +01:00			`# Select this if you need host eudev tools (e.g. udevadm)`
			`config BR2_PACKAGE_HOST_EUDEV`
			`bool`