1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
3 #ifndef foosdshutdownhfoo
4 #define foosdshutdownhfoo
7 This file is part of systemd.
9 Copyright 2010 Lennart Poettering
11 systemd is free software; you can redistribute it and/or modify it
12 under the terms of the GNU General Public License as published by
13 the Free Software Foundation; either version 2 of the License, or
14 (at your option) any later version.
16 systemd is distributed in the hope that it will be useful, but
17 WITHOUT ANY WARRANTY; without even the implied warranty of
18 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 General Public License for more details.
21 You should have received a copy of the GNU General Public License
22 along with systemd; If not, see <http://www.gnu.org/licenses/>.
25 /* Interface for scheduling and cancelling timed shutdowns. */
29 typedef enum sd_shutdown_mode {
31 SD_SHUTDOWN_REBOOT = 'r',
32 SD_SHUTDOWN_POWEROFF = 'P',
33 SD_SHUTDOWN_HALT = 'H',
34 SD_SHUTDOWN_KEXEC = 'K'
37 /* Calculate the size of the message as "offsetof(struct
38 * sd_shutdown_command, wall_message) +
39 * strlen(command.wall_message)" */
40 __attribute__((packed)) struct sd_shutdown_command {
41 /* Microseconds after the epoch 1970 UTC */
44 /* H, P, r, i.e. the switches usually passed to
45 * /usr/bin/shutdown to select whether to halt, power-off or
46 * reboot the machine */
47 sd_shutdown_mode_t mode:8;
49 /* If non-zero, don't actually shut down, just pretend */
52 /* If non-zero, send our wall message */
55 /* The wall message to send around. Leave empty for the
56 * default wall message */
60 /* The scheme is very simple:
62 * To schedule a shutdown, simply fill in and send a single
63 * AF_UNIX/SOCK_DGRAM datagram with the structure above suffixed with
64 * the wall message to the socket /run/systemd/shutdownd (leave an
65 * empty wall message for the default shutdown message). To calculate
66 * the size of the message use "offsetof(struct sd_shutdown_command,
67 * wall_message) + strlen(command.wall_message)".
69 * To cancel a shutdown, do the same, but send an fully zeroed out
72 * To be notified about scheduled shutdowns, create an inotify watch
73 * on /run/shutdown/. Whenever a file called "scheduled" appears a
74 * shutdown is scheduled. If it is removed it is canceled. It is
75 * replaced the scheduled shutdown has been changed. The file contains
76 * a simple environment-like block, that contains information about
77 * the scheduled shutdown:
80 * encodes the time for the shutdown in usecs since the epoch UTC,
81 * formatted as numeric string.
84 * is 1 if a wall message shall be sent
87 * is 1 if a dry run shutdown is scheduled
90 * is the shutdown mode, one of "poweroff", "reboot", "halt", "kexec"
93 * is the wall message to use, with all special characters escape in C style.
95 * Note that some fields might be missing if they do not apply.
97 * Note that the file is first written to a temporary file and then
98 * renamed, in order to provide atomic properties for readers: if the
99 * file exists under the name "scheduled" it is guaranteed to be fully
100 * written. A reader should ignore all files in that directory by any
103 * Scheduled shutdowns are only accepted from privileged processes,
104 * but the directory may be watched and the file in it read by