628c89cc68
This change introduces a new state "tentative" for device units. Device units are considered "plugged" when udev announced them, "dead" when they are not available in the kernel, and "tentative" when they are referenced in /proc/self/mountinfo or /proc/swaps but not (yet) announced via udev. This should fix a race when device nodes (like loop devices) are created and immediately mounted. Previously, systemd might end up seeing the mount unit before the device, and would thus pull down the mount because its BindTo dependency on the device would not be fulfilled.
64 lines
1.9 KiB
C
64 lines
1.9 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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#pragma once
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/***
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This file is part of systemd.
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Copyright 2010 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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typedef struct Device Device;
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/* We simply watch devices, we cannot plug/unplug them. That
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* simplifies the state engine greatly */
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typedef enum DeviceState {
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DEVICE_DEAD,
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DEVICE_TENTATIVE, /* mounted or swapped, but not (yet) announced by udev */
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DEVICE_PLUGGED, /* announced by udev */
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_DEVICE_STATE_MAX,
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_DEVICE_STATE_INVALID = -1
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} DeviceState;
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typedef enum DeviceFound {
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DEVICE_NOT_FOUND = 0,
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DEVICE_FOUND_UDEV = 1,
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DEVICE_FOUND_MOUNT = 2,
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DEVICE_FOUND_SWAP = 4,
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} DeviceFound;
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struct Device {
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Unit meta;
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char *sysfs;
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DeviceFound found;
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/* In order to be able to distinguish dependencies on
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different device nodes we might end up creating multiple
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devices for the same sysfs path. We chain them up here. */
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LIST_FIELDS(struct Device, same_sysfs);
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DeviceState state;
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};
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extern const UnitVTable device_vtable;
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const char* device_state_to_string(DeviceState i) _const_;
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DeviceState device_state_from_string(const char *s) _pure_;
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int device_found_node(Manager *m, const char *node, bool add, DeviceFound found, bool now);
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