1 /* SPDX-License-Identifier: LGPL-2.1+ */
2 #ifndef foosddaemonhfoo
3 #define foosddaemonhfoo
7 systemd is free software; you can redistribute it and/or modify it
8 under the terms of the GNU Lesser General Public License as published by
9 the Free Software Foundation; either version 2.1 of the License, or
10 (at your option) any later version.
12 systemd is distributed in the hope that it will be useful, but
13 WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Lesser General Public License for more details.
17 You should have received a copy of the GNU Lesser General Public License
18 along with systemd; If not, see <http://www.gnu.org/licenses/>.
22 #include <sys/types.h>
23 #include <sys/socket.h>
25 #include "_sd-common.h"
27 _SD_BEGIN_DECLARATIONS;
30 The following functionality is provided:
32 - Support for logging with log levels on stderr
33 - File descriptor passing for socket-based activation
34 - Daemon startup and status notification
35 - Detection of systemd boots
37 See sd-daemon(3) for more information.
41 Log levels for usage on stderr:
43 fprintf(stderr, SD_NOTICE "Hello World!\n");
45 This is similar to printk() usage in the kernel.
47 #define SD_EMERG "<0>" /* system is unusable */
48 #define SD_ALERT "<1>" /* action must be taken immediately */
49 #define SD_CRIT "<2>" /* critical conditions */
50 #define SD_ERR "<3>" /* error conditions */
51 #define SD_WARNING "<4>" /* warning conditions */
52 #define SD_NOTICE "<5>" /* normal but significant condition */
53 #define SD_INFO "<6>" /* informational */
54 #define SD_DEBUG "<7>" /* debug-level messages */
56 /* The first passed file descriptor is fd 3 */
57 #define SD_LISTEN_FDS_START 3
60 Returns how many file descriptors have been passed, or a negative
61 errno code on failure. Optionally, removes the $LISTEN_FDS and
62 $LISTEN_PID file descriptors from the environment (recommended, but
63 problematic in threaded environments). If r is the return value of
64 this function you'll find the file descriptors passed as fds
65 SD_LISTEN_FDS_START to SD_LISTEN_FDS_START+r-1. Returns a negative
66 errno style error code on failure. This function call ensures that
67 the FD_CLOEXEC flag is set for the passed file descriptors, to make
68 sure they are not passed on to child processes. If FD_CLOEXEC shall
69 not be set, the caller needs to unset it after this call for all file
70 descriptors that are used.
72 See sd_listen_fds(3) for more information.
74 int sd_listen_fds(int unset_environment);
76 int sd_listen_fds_with_names(int unset_environment, char ***names);
79 Helper call for identifying a passed file descriptor. Returns 1 if
80 the file descriptor is a FIFO in the file system stored under the
81 specified path, 0 otherwise. If path is NULL a path name check will
82 not be done and the call only verifies if the file descriptor
83 refers to a FIFO. Returns a negative errno style error code on
86 See sd_is_fifo(3) for more information.
88 int sd_is_fifo(int fd, const char *path);
91 Helper call for identifying a passed file descriptor. Returns 1 if
92 the file descriptor is a special character device on the file
93 system stored under the specified path, 0 otherwise.
94 If path is NULL a path name check will not be done and the call
95 only verifies if the file descriptor refers to a special character.
96 Returns a negative errno style error code on failure.
98 See sd_is_special(3) for more information.
100 int sd_is_special(int fd, const char *path);
103 Helper call for identifying a passed file descriptor. Returns 1 if
104 the file descriptor is a socket of the specified family (AF_INET,
105 ...) and type (SOCK_DGRAM, SOCK_STREAM, ...), 0 otherwise. If
106 family is 0 a socket family check will not be done. If type is 0 a
107 socket type check will not be done and the call only verifies if
108 the file descriptor refers to a socket. If listening is > 0 it is
109 verified that the socket is in listening mode. (i.e. listen() has
110 been called) If listening is == 0 it is verified that the socket is
111 not in listening mode. If listening is < 0 no listening mode check
112 is done. Returns a negative errno style error code on failure.
114 See sd_is_socket(3) for more information.
116 int sd_is_socket(int fd, int family, int type, int listening);
119 Helper call for identifying a passed file descriptor. Returns 1 if
120 the file descriptor is an Internet socket, of the specified family
121 (either AF_INET or AF_INET6) and the specified type (SOCK_DGRAM,
122 SOCK_STREAM, ...), 0 otherwise. If version is 0 a protocol version
123 check is not done. If type is 0 a socket type check will not be
124 done. If port is 0 a socket port check will not be done. The
125 listening flag is used the same way as in sd_is_socket(). Returns a
126 negative errno style error code on failure.
128 See sd_is_socket_inet(3) for more information.
130 int sd_is_socket_inet(int fd, int family, int type, int listening, uint16_t port);
133 Helper call for identifying a passed file descriptor. Returns 1 if the
134 file descriptor is an Internet socket of the specified type
135 (SOCK_DGRAM, SOCK_STREAM, ...), and if the address of the socket is
136 the same as the address specified by addr. The listening flag is used
137 the same way as in sd_is_socket(). Returns a negative errno style
138 error code on failure.
140 See sd_is_socket_sockaddr(3) for more information.
142 int sd_is_socket_sockaddr(int fd, int type, const struct sockaddr* addr, unsigned addr_len, int listening);
145 Helper call for identifying a passed file descriptor. Returns 1 if
146 the file descriptor is an AF_UNIX socket of the specified type
147 (SOCK_DGRAM, SOCK_STREAM, ...) and path, 0 otherwise. If type is 0
148 a socket type check will not be done. If path is NULL a socket path
149 check will not be done. For normal AF_UNIX sockets set length to
150 0. For abstract namespace sockets set length to the length of the
151 socket name (including the initial 0 byte), and pass the full
152 socket path in path (including the initial 0 byte). The listening
153 flag is used the same way as in sd_is_socket(). Returns a negative
154 errno style error code on failure.
156 See sd_is_socket_unix(3) for more information.
158 int sd_is_socket_unix(int fd, int type, int listening, const char *path, size_t length);
160 #if 0 /** UNNEEDED by elogind **/
162 Helper call for identifying a passed file descriptor. Returns 1 if
163 the file descriptor is a POSIX Message Queue of the specified name,
164 0 otherwise. If path is NULL a message queue name check is not
165 done. Returns a negative errno style error code on failure.
167 See sd_is_mq(3) for more information.
169 int sd_is_mq(int fd, const char *path);
173 Informs systemd about changed daemon state. This takes a number of
174 newline separated environment-style variable assignments in a
175 string. The following variables are known:
177 MAINPID=... The main PID of a daemon, in case elogind did not
178 fork off the process itself. Example: "MAINPID=4711"
180 READY=1 Tells elogind that daemon startup or daemon reload
181 is finished (only relevant for services of Type=notify).
182 The passed argument is a boolean "1" or "0". Since there
183 is little value in signaling non-readiness the only
184 value daemons should send is "READY=1".
186 RELOADING=1 Tell elogind that the daemon began reloading its
187 configuration. When the configuration has been
188 reloaded completely, READY=1 should be sent to inform
191 STOPPING=1 Tells elogind that the daemon is about to go down.
193 STATUS=... Passes a single-line status string back to systemd
194 that describes the daemon state. This is free-form
195 and can be used for various purposes: general state
196 feedback, fsck-like programs could pass completion
197 percentages and failing programs could pass a human
198 readable error message. Example: "STATUS=Completed
199 66% of file system check..."
201 ERRNO=... If a daemon fails, the errno-style error code,
202 formatted as string. Example: "ERRNO=2" for ENOENT.
204 BUSERROR=... If a daemon fails, the D-Bus error-style error
205 code. Example: "BUSERROR=org.freedesktop.DBus.Error.TimedOut"
207 WATCHDOG=1 Tells systemd to update the watchdog timestamp.
208 Services using this feature should do this in
209 regular intervals. A watchdog framework can use the
210 timestamps to detect failed services. Also see
211 sd_watchdog_enabled() below.
214 Reset watchdog_usec value during runtime.
215 To reset watchdog_usec value, start the service again.
216 Example: "WATCHDOG_USEC=20000000"
218 FDSTORE=1 Store the file descriptors passed along with the
219 message in the per-service file descriptor store,
220 and pass them to the main process again on next
221 invocation. This variable is only supported with
222 sd_pid_notify_with_fds().
225 Remove one or more file descriptors from the file
226 descriptor store, identified by the name specified
227 in FDNAME=, see below.
229 FDNAME= A name to assign to new file descriptors stored in the
230 file descriptor store, or the name of the file descriptors
231 to remove in case of FDSTOREREMOVE=1.
233 Daemons can choose to send additional variables. However, it is
234 recommended to prefix variable names not listed above with X_.
236 Returns a negative errno-style error code on failure. Returns > 0
237 if systemd could be notified, 0 if it couldn't possibly because
238 systemd is not running.
240 Example: When a daemon finished starting up, it could issue this
241 call to notify systemd about it:
243 sd_notify(0, "READY=1");
245 See sd_notifyf() for more complete examples.
247 See sd_notify(3) for more information.
249 int sd_notify(int unset_environment, const char *state);
252 Similar to sd_notify() but takes a format string.
254 Example 1: A daemon could send the following after initialization:
256 sd_notifyf(0, "READY=1\n"
257 "STATUS=Processing requests...\n"
259 (unsigned long) getpid());
261 Example 2: A daemon could send the following shortly before
264 sd_notifyf(0, "STATUS=Failed to start up: %s\n"
269 See sd_notifyf(3) for more information.
271 int sd_notifyf(int unset_environment, const char *format, ...) _sd_printf_(2,3);
274 Similar to sd_notify(), but send the message on behalf of another
275 process, if the appropriate permissions are available.
277 int sd_pid_notify(pid_t pid, int unset_environment, const char *state);
280 Similar to sd_notifyf(), but send the message on behalf of another
281 process, if the appropriate permissions are available.
283 int sd_pid_notifyf(pid_t pid, int unset_environment, const char *format, ...) _sd_printf_(3,4);
286 Similar to sd_pid_notify(), but also passes the specified fd array
287 to the service manager for storage. This is particularly useful for
290 int sd_pid_notify_with_fds(pid_t pid, int unset_environment, const char *state, const int *fds, unsigned n_fds);
293 Returns > 0 if the system was booted with systemd. Returns < 0 on
294 error. Returns 0 if the system was not booted with systemd. Note
295 that all of the functions above handle non-systemd boots just
296 fine. You should NOT protect them with a call to this function. Also
297 note that this function checks whether the system, not the user
298 session is controlled by systemd. However the functions above work
299 for both user and system services.
301 See sd_booted(3) for more information.
306 Returns > 0 if the service manager expects watchdog keep-alive
307 events to be sent regularly via sd_notify(0, "WATCHDOG=1"). Returns
308 0 if it does not expect this. If the usec argument is non-NULL
309 returns the watchdog timeout in µs after which the service manager
310 will act on a process that has not sent a watchdog keep alive
311 message. This function is useful to implement services that
312 recognize automatically if they are being run under supervision of
313 systemd with WatchdogSec= set. It is recommended for clients to
314 generate keep-alive pings via sd_notify(0, "WATCHDOG=1") every half
315 of the returned time.
317 See sd_watchdog_enabled(3) for more information.
319 int sd_watchdog_enabled(int unset_environment, uint64_t *usec);
321 _SD_END_DECLARATIONS;