path: root/system
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authorGravatar Yann E. MORIN <yann.morin.1998@free.fr>2017-08-02 00:52:22 +0200
committerGravatar Thomas Petazzoni <thomas.petazzoni@free-electrons.com>2017-08-02 20:58:27 +0200
commit4628b6f3b4512ec7cfb3c08ad4fe0ec40e1c5cc1 (patch)
tree31902fb666d391b50f73a4afb8be6dcf842e61d5 /system
parent76fc9275f14ec295b0125910464969bfa7441b85 (diff)
fs: add pre- and post-command hooks
In some cases, the directory structure we want in the filesystem is not exactly what we have in target/ For example, when systemd is used on a read-only rootfs, /var must be a tmpfs. However, we may have packages that install stuff in there, and set important rights (via the permission-table). So, at build time, we need /var to be a symlink to the remanent location (/usr/share/factory) while at runtime we need /var to be a directory. One option would have been to have /var as a real directory even during build time, and in a target-finalize hook, move everything out of there and into the "factory" location. However, that's not possible because it's too early: some packages may want to set ownership and/or acces rights on directories or files in /var, and this is only done in the fakeroot script, which is called only later during the assembling of the filesystem images. Also, there would have been no way to undo the tweak (i.e. we need to restore the /var symlink so that subsequent builds continue to work) if it were done as a target-finalize hook. The only solution is to allow packages to register pre- and post-hooks that are called right before and right after the rootfs commands are executed, and inside in the fakeroot script. We can however not re-use the BR2_ROOTFS_POST_FAKEROOT_SCRIPT feature either because it is done before the filesystem command, but there is nothing that is done after. Also, we don't want to add to, and modify a user-supplied variable. So, we introduce two new variables that packages can set to add the commands they need to run to tweak the filesystem right at the last moment. Those hooks are not documented on-purpose; they are probably going to only ever be used by systemd. Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr> Reviewed-by: Romain Naour <romain.naour@gmail.com> Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Diffstat (limited to 'system')
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