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systemd/units/modprobe@.service

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units: Split modprobing out into a separate service unit Devices referred to by `DeviceAllow=` sandboxing are resolved into their corresponding major numbers when the unit is loaded by looking at `/proc/devices`. If a reference is made to a device which is not yet available, the `DeviceAllow` is ignored and the unit's processes cannot access that device. In both logind and nspawn, we have `DeviceAllow=` lines, and `modprobe` in `ExecStartPre=` to load some kernel modules. Those kernel modules cause device nodes to become available when they are loaded: the device nodes may not exist when the unit itself is loaded. This means that the unit's processes will not be able to access the device since the `DeviceAllow=` will have been resolved earlier and denied it. One way to fix this would be to re-evaluate the available devices and re-apply the policy to the cgroup, but this cannot work atomically on cgroupsv1. So we fall back to a second approach: instead of running `modprobe` via `ExecStartPre`, we move this out to a separate unit and order it before the units which want the module. Closes #14322. Fixes: #13943.
2020-01-07 14:33:29 +00:00
# SPDX-License-Identifier: LGPL-2.1+
#
# This file is part of systemd.
#
# systemd is free software; you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 of the License, or
# (at your option) any later version.
[Unit]
units: tweaks to modprobe@.service Let's use uppercase wording in the description string, like we usually do. Let's allow using this service in early boot. If it's pulled into the initial transaction it's better to finish loading this before sysinit.target. Don't bother with this in containers that lack CAP_SYS_MODULE
2020-01-07 18:54:24 +01:00
Description=Load Kernel Module %i
DefaultDependencies=no
Before=sysinit.target
units: Split modprobing out into a separate service unit Devices referred to by `DeviceAllow=` sandboxing are resolved into their corresponding major numbers when the unit is loaded by looking at `/proc/devices`. If a reference is made to a device which is not yet available, the `DeviceAllow` is ignored and the unit's processes cannot access that device. In both logind and nspawn, we have `DeviceAllow=` lines, and `modprobe` in `ExecStartPre=` to load some kernel modules. Those kernel modules cause device nodes to become available when they are loaded: the device nodes may not exist when the unit itself is loaded. This means that the unit's processes will not be able to access the device since the `DeviceAllow=` will have been resolved earlier and denied it. One way to fix this would be to re-evaluate the available devices and re-apply the policy to the cgroup, but this cannot work atomically on cgroupsv1. So we fall back to a second approach: instead of running `modprobe` via `ExecStartPre`, we move this out to a separate unit and order it before the units which want the module. Closes #14322. Fixes: #13943.
2020-01-07 14:33:29 +00:00
Documentation=man:modprobe(8)
units: tweaks to modprobe@.service Let's use uppercase wording in the description string, like we usually do. Let's allow using this service in early boot. If it's pulled into the initial transaction it's better to finish loading this before sysinit.target. Don't bother with this in containers that lack CAP_SYS_MODULE
2020-01-07 18:54:24 +01:00
ConditionCapability=CAP_SYS_MODULE
units: skip modprobe@.service if the unit appears to be already loaded Possible alternative to #14819. For me, setting RemainAfterExit=yes would be OK, but if people think that it might cause issues, then this could be a reasonable alternative that still let's us skip the invocation of the separate binary.
2020-03-05 07:20:49 +01:00
ConditionPathExists=!/sys/module/%I
units: Split modprobing out into a separate service unit Devices referred to by `DeviceAllow=` sandboxing are resolved into their corresponding major numbers when the unit is loaded by looking at `/proc/devices`. If a reference is made to a device which is not yet available, the `DeviceAllow` is ignored and the unit's processes cannot access that device. In both logind and nspawn, we have `DeviceAllow=` lines, and `modprobe` in `ExecStartPre=` to load some kernel modules. Those kernel modules cause device nodes to become available when they are loaded: the device nodes may not exist when the unit itself is loaded. This means that the unit's processes will not be able to access the device since the `DeviceAllow=` will have been resolved earlier and denied it. One way to fix this would be to re-evaluate the available devices and re-apply the policy to the cgroup, but this cannot work atomically on cgroupsv1. So we fall back to a second approach: instead of running `modprobe` via `ExecStartPre`, we move this out to a separate unit and order it before the units which want the module. Closes #14322. Fixes: #13943.
2020-01-07 14:33:29 +00:00
[Service]
Type=oneshot
ExecStart=-/sbin/modprobe -abq %I
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