1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
3 #ifndef foosddaemonhfoo
4 #define foosddaemonhfoo
7 This file is part of systemd.
9 Copyright 2013 Lennart Poettering
11 systemd is free software; you can redistribute it and/or modify it
12 under the terms of the GNU Lesser General Public License as published by
13 the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
21 You should have received a copy of the GNU Lesser General Public License
22 along with systemd; If not, see <http://www.gnu.org/licenses/>.
25 #include <sys/types.h>
28 #include "_sd-common.h"
30 _SD_BEGIN_DECLARATIONS;
33 The following functionality is provided:
35 - Support for logging with log levels on stderr
36 - File descriptor passing for socket-based activation
37 - Daemon startup and status notification
38 - Detection of systemd boots
40 See sd-daemon(3) for more information.
44 Log levels for usage on stderr:
46 fprintf(stderr, SD_NOTICE "Hello World!\n");
48 This is similar to printk() usage in the kernel.
50 #define SD_EMERG "<0>" /* system is unusable */
51 #define SD_ALERT "<1>" /* action must be taken immediately */
52 #define SD_CRIT "<2>" /* critical conditions */
53 #define SD_ERR "<3>" /* error conditions */
54 #define SD_WARNING "<4>" /* warning conditions */
55 #define SD_NOTICE "<5>" /* normal but significant condition */
56 #define SD_INFO "<6>" /* informational */
57 #define SD_DEBUG "<7>" /* debug-level messages */
59 /* The first passed file descriptor is fd 3 */
60 #define SD_LISTEN_FDS_START 3
62 /// UNNEEDED by elogind
65 Returns how many file descriptors have been passed, or a negative
66 errno code on failure. Optionally, removes the $LISTEN_FDS and
67 $LISTEN_PID file descriptors from the environment (recommended, but
68 problematic in threaded environments). If r is the return value of
69 this function you'll find the file descriptors passed as fds
70 SD_LISTEN_FDS_START to SD_LISTEN_FDS_START+r-1. Returns a negative
71 errno style error code on failure. This function call ensures that
72 the FD_CLOEXEC flag is set for the passed file descriptors, to make
73 sure they are not passed on to child processes. If FD_CLOEXEC shall
74 not be set, the caller needs to unset it after this call for all file
75 descriptors that are used.
77 See sd_listen_fds(3) for more information.
79 int sd_listen_fds(int unset_environment);
81 int sd_listen_fds_with_names(int unset_environment, char ***names);
84 Helper call for identifying a passed file descriptor. Returns 1 if
85 the file descriptor is a FIFO in the file system stored under the
86 specified path, 0 otherwise. If path is NULL a path name check will
87 not be done and the call only verifies if the file descriptor
88 refers to a FIFO. Returns a negative errno style error code on
91 See sd_is_fifo(3) for more information.
93 int sd_is_fifo(int fd, const char *path);
96 Helper call for identifying a passed file descriptor. Returns 1 if
97 the file descriptor is a special character device on the file
98 system stored under the specified path, 0 otherwise.
99 If path is NULL a path name check will not be done and the call
100 only verifies if the file descriptor refers to a special character.
101 Returns a negative errno style error code on failure.
103 See sd_is_special(3) for more information.
105 int sd_is_special(int fd, const char *path);
109 Helper call for identifying a passed file descriptor. Returns 1 if
110 the file descriptor is a socket of the specified family (AF_INET,
111 ...) and type (SOCK_DGRAM, SOCK_STREAM, ...), 0 otherwise. If
112 family is 0 a socket family check will not be done. If type is 0 a
113 socket type check will not be done and the call only verifies if
114 the file descriptor refers to a socket. If listening is > 0 it is
115 verified that the socket is in listening mode. (i.e. listen() has
116 been called) If listening is == 0 it is verified that the socket is
117 not in listening mode. If listening is < 0 no listening mode check
118 is done. Returns a negative errno style error code on failure.
120 See sd_is_socket(3) for more information.
122 int sd_is_socket(int fd, int family, int type, int listening);
124 /// UNNEEDED by elogind
127 Helper call for identifying a passed file descriptor. Returns 1 if
128 the file descriptor is an Internet socket, of the specified family
129 (either AF_INET or AF_INET6) and the specified type (SOCK_DGRAM,
130 SOCK_STREAM, ...), 0 otherwise. If version is 0 a protocol version
131 check is not done. If type is 0 a socket type check will not be
132 done. If port is 0 a socket port check will not be done. The
133 listening flag is used the same way as in sd_is_socket(). Returns a
134 negative errno style error code on failure.
136 See sd_is_socket_inet(3) for more information.
138 int sd_is_socket_inet(int fd, int family, int type, int listening, uint16_t port);
141 Helper call for identifying a passed file descriptor. Returns 1 if
142 the file descriptor is an AF_UNIX socket of the specified type
143 (SOCK_DGRAM, SOCK_STREAM, ...) and path, 0 otherwise. If type is 0
144 a socket type check will not be done. If path is NULL a socket path
145 check will not be done. For normal AF_UNIX sockets set length to
146 0. For abstract namespace sockets set length to the length of the
147 socket name (including the initial 0 byte), and pass the full
148 socket path in path (including the initial 0 byte). The listening
149 flag is used the same way as in sd_is_socket(). Returns a negative
150 errno style error code on failure.
152 See sd_is_socket_unix(3) for more information.
154 int sd_is_socket_unix(int fd, int type, int listening, const char *path, size_t length);
157 Helper call for identifying a passed file descriptor. Returns 1 if
158 the file descriptor is a POSIX Message Queue of the specified name,
159 0 otherwise. If path is NULL a message queue name check is not
160 done. Returns a negative errno style error code on failure.
162 See sd_is_mq(3) for more information.
164 int sd_is_mq(int fd, const char *path);
168 Informs systemd about changed daemon state. This takes a number of
169 newline separated environment-style variable assignments in a
170 string. The following variables are known:
172 READY=1 Tells systemd that daemon startup is finished (only
173 relevant for services of Type=notify). The passed
174 argument is a boolean "1" or "0". Since there is
175 little value in signaling non-readiness the only
176 value daemons should send is "READY=1".
178 STATUS=... Passes a single-line status string back to systemd
179 that describes the daemon state. This is free-form
180 and can be used for various purposes: general state
181 feedback, fsck-like programs could pass completion
182 percentages and failing programs could pass a human
183 readable error message. Example: "STATUS=Completed
184 66% of file system check..."
186 ERRNO=... If a daemon fails, the errno-style error code,
187 formatted as string. Example: "ERRNO=2" for ENOENT.
189 BUSERROR=... If a daemon fails, the D-Bus error-style error
190 code. Example: "BUSERROR=org.freedesktop.DBus.Error.TimedOut"
192 MAINPID=... The main pid of a daemon, in case systemd did not
193 fork off the process itself. Example: "MAINPID=4711"
195 WATCHDOG=1 Tells systemd to update the watchdog timestamp.
196 Services using this feature should do this in
197 regular intervals. A watchdog framework can use the
198 timestamps to detect failed services. Also see
199 sd_watchdog_enabled() below.
201 FDSTORE=1 Store the file descriptors passed along with the
202 message in the per-service file descriptor store,
203 and pass them to the main process again on next
204 invocation. This variable is only supported with
205 sd_pid_notify_with_fds().
207 Daemons can choose to send additional variables. However, it is
208 recommended to prefix variable names not listed above with X_.
210 Returns a negative errno-style error code on failure. Returns > 0
211 if systemd could be notified, 0 if it couldn't possibly because
212 systemd is not running.
214 Example: When a daemon finished starting up, it could issue this
215 call to notify systemd about it:
217 sd_notify(0, "READY=1");
219 See sd_notifyf() for more complete examples.
221 See sd_notify(3) for more information.
223 int sd_notify(int unset_environment, const char *state);
225 /// UNNEEDED by elogind
228 Similar to sd_notify() but takes a format string.
230 Example 1: A daemon could send the following after initialization:
232 sd_notifyf(0, "READY=1\n"
233 "STATUS=Processing requests...\n"
235 (unsigned long) getpid());
237 Example 2: A daemon could send the following shortly before
240 sd_notifyf(0, "STATUS=Failed to start up: %s\n"
245 See sd_notifyf(3) for more information.
247 int sd_notifyf(int unset_environment, const char *format, ...) _sd_printf_(2,3);
250 Similar to sd_notify(), but send the message on behalf of another
251 process, if the appropriate permissions are available.
253 int sd_pid_notify(pid_t pid, int unset_environment, const char *state);
256 Similar to sd_notifyf(), but send the message on behalf of another
257 process, if the appropriate permissions are available.
259 int sd_pid_notifyf(pid_t pid, int unset_environment, const char *format, ...) _sd_printf_(3,4);
263 Similar to sd_pid_notify(), but also passes the specified fd array
264 to the service manager for storage. This is particularly useful for
267 int sd_pid_notify_with_fds(pid_t pid, int unset_environment, const char *state, const int *fds, unsigned n_fds);
269 /// UNNEEDED by elogind
272 Returns > 0 if the system was booted with systemd. Returns < 0 on
273 error. Returns 0 if the system was not booted with systemd. Note
274 that all of the functions above handle non-systemd boots just
275 fine. You should NOT protect them with a call to this function. Also
276 note that this function checks whether the system, not the user
277 session is controlled by systemd. However the functions above work
278 for both user and system services.
280 See sd_booted(3) for more information.
286 Returns > 0 if the service manager expects watchdog keep-alive
287 events to be sent regularly via sd_notify(0, "WATCHDOG=1"). Returns
288 0 if it does not expect this. If the usec argument is non-NULL
289 returns the watchdog timeout in µs after which the service manager
290 will act on a process that has not sent a watchdog keep alive
291 message. This function is useful to implement services that
292 recognize automatically if they are being run under supervision of
293 systemd with WatchdogSec= set. It is recommended for clients to
294 generate keep-alive pings via sd_notify(0, "WATCHDOG=1") every half
295 of the returned time.
297 See sd_watchdog_enabled(3) for more information.
299 int sd_watchdog_enabled(int unset_environment, uint64_t *usec);
301 _SD_END_DECLARATIONS;