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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
#ifndef foosdshutdownhfoo
#define foosdshutdownhfoo
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
/* Interface for scheduling and cancelling timed shutdowns. */
#include <inttypes.h>
typedef enum sd_shutdown_mode {
SD_SHUTDOWN_NONE = 0,
SD_SHUTDOWN_REBOOT = 'r',
SD_SHUTDOWN_POWEROFF = 'P',
SD_SHUTDOWN_HALT = 'H',
SD_SHUTDOWN_KEXEC = 'K'
} sd_shutdown_mode_t;
/* Calculate the size of the message as "offsetof(struct
* sd_shutdown_command, wall_message) +
* strlen(command.wall_message)" */
__attribute__((packed)) struct sd_shutdown_command {
/* Microseconds after the epoch 1970 UTC */
uint64_t usec;
/* H, P, r, i.e. the switches usually passed to
* /usr/bin/shutdown to select whether to halt, power-off or
* reboot the machine */
sd_shutdown_mode_t mode:8;
/* If non-zero, don't actually shut down, just pretend */
unsigned dry_run:1;
/* If non-zero, send our wall message */
unsigned warn_wall:1;
/* The wall message to send around. Leave empty for the
* default wall message */
char wall_message[];
};
/* The scheme is very simple:
*
* To schedule a shutdown, simply fill in and send a single
* AF_UNIX/SOCK_DGRAM datagram with the structure above suffixed with
* the wall message to the socket /run/systemd/shutdownd (leave an
* empty wall message for the default shutdown message). To calculate
* the size of the message use "offsetof(struct sd_shutdown_command,
* wall_message) + strlen(command.wall_message)".
*
* To cancel a shutdown, do the same, but send an fully zeroed out
* structure.
*
* To be notified about scheduled shutdowns, create an inotify watch
* on /run/shutdown/. Whenever a file called "scheduled" appears a
* shutdown is scheduled. If it is removed it is canceled. It is
* replaced the scheduled shutdown has been changed. The file contains
* a simple environment-like block, that contains information about
* the scheduled shutdown:
*
* USEC=
* encodes the time for the shutdown in usecs since the epoch UTC,
* formatted as numeric string.
*
* WARN_WALL=
* is 1 if a wall message shall be sent
*
* DRY_RUN=
* is 1 if a dry run shutdown is scheduled
*
* MODE=
* is the shutdown mode, one of "poweroff", "reboot", "halt", "kexec"
*
* WALL_MESSAGE=
* is the wall message to use, with all special characters escape in C style.
*
* Note that some fields might be missing if they do not apply.
*
* Note that the file is first written to a temporary file and then
* renamed, in order to provide atomic properties for readers: if the
* file exists under the name "scheduled" it is guaranteed to be fully
* written. A reader should ignore all files in that directory by any
* other name.
*
* Scheduled shutdowns are only accepted from privileged processes,
* but the directory may be watched and the file in it read by
* anybody.
*/
#endif
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