1 #ifndef foosddaemonhfoo
2 #define foosddaemonhfoo
5 This file is part of systemd.
7 Copyright 2013 Lennart Poettering
9 systemd is free software; you can redistribute it and/or modify it
10 under the terms of the GNU Lesser General Public License as published by
11 the Free Software Foundation; either version 2.1 of the License, or
12 (at your option) any later version.
14 systemd is distributed in the hope that it will be useful, but
15 WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 Lesser General Public License for more details.
19 You should have received a copy of the GNU Lesser General Public License
20 along with systemd; If not, see <http://www.gnu.org/licenses/>.
24 #include <sys/types.h>
25 #include <sys/socket.h>
27 #include "_sd-common.h"
29 _SD_BEGIN_DECLARATIONS;
32 The following functionality is provided:
34 - Support for logging with log levels on stderr
35 - File descriptor passing for socket-based activation
36 - Daemon startup and status notification
37 - Detection of systemd boots
39 See sd-daemon(3) for more information.
43 Log levels for usage on stderr:
45 fprintf(stderr, SD_NOTICE "Hello World!\n");
47 This is similar to printk() usage in the kernel.
49 #define SD_EMERG "<0>" /* system is unusable */
50 #define SD_ALERT "<1>" /* action must be taken immediately */
51 #define SD_CRIT "<2>" /* critical conditions */
52 #define SD_ERR "<3>" /* error conditions */
53 #define SD_WARNING "<4>" /* warning conditions */
54 #define SD_NOTICE "<5>" /* normal but significant condition */
55 #define SD_INFO "<6>" /* informational */
56 #define SD_DEBUG "<7>" /* debug-level messages */
58 /* The first passed file descriptor is fd 3 */
59 #define SD_LISTEN_FDS_START 3
62 Returns how many file descriptors have been passed, or a negative
63 errno code on failure. Optionally, removes the $LISTEN_FDS and
64 $LISTEN_PID file descriptors from the environment (recommended, but
65 problematic in threaded environments). If r is the return value of
66 this function you'll find the file descriptors passed as fds
67 SD_LISTEN_FDS_START to SD_LISTEN_FDS_START+r-1. Returns a negative
68 errno style error code on failure. This function call ensures that
69 the FD_CLOEXEC flag is set for the passed file descriptors, to make
70 sure they are not passed on to child processes. If FD_CLOEXEC shall
71 not be set, the caller needs to unset it after this call for all file
72 descriptors that are used.
74 See sd_listen_fds(3) for more information.
76 int sd_listen_fds(int unset_environment);
78 int sd_listen_fds_with_names(int unset_environment, char ***names);
81 Helper call for identifying a passed file descriptor. Returns 1 if
82 the file descriptor is a FIFO in the file system stored under the
83 specified path, 0 otherwise. If path is NULL a path name check will
84 not be done and the call only verifies if the file descriptor
85 refers to a FIFO. Returns a negative errno style error code on
88 See sd_is_fifo(3) for more information.
90 int sd_is_fifo(int fd, const char *path);
93 Helper call for identifying a passed file descriptor. Returns 1 if
94 the file descriptor is a special character device on the file
95 system stored under the specified path, 0 otherwise.
96 If path is NULL a path name check will not be done and the call
97 only verifies if the file descriptor refers to a special character.
98 Returns a negative errno style error code on failure.
100 See sd_is_special(3) for more information.
102 int sd_is_special(int fd, const char *path);
105 Helper call for identifying a passed file descriptor. Returns 1 if
106 the file descriptor is a socket of the specified family (AF_INET,
107 ...) and type (SOCK_DGRAM, SOCK_STREAM, ...), 0 otherwise. If
108 family is 0 a socket family check will not be done. If type is 0 a
109 socket type check will not be done and the call only verifies if
110 the file descriptor refers to a socket. If listening is > 0 it is
111 verified that the socket is in listening mode. (i.e. listen() has
112 been called) If listening is == 0 it is verified that the socket is
113 not in listening mode. If listening is < 0 no listening mode check
114 is done. Returns a negative errno style error code on failure.
116 See sd_is_socket(3) for more information.
118 int sd_is_socket(int fd, int family, int type, int listening);
121 Helper call for identifying a passed file descriptor. Returns 1 if
122 the file descriptor is an Internet socket, of the specified family
123 (either AF_INET or AF_INET6) and the specified type (SOCK_DGRAM,
124 SOCK_STREAM, ...), 0 otherwise. If version is 0 a protocol version
125 check is not done. If type is 0 a socket type check will not be
126 done. If port is 0 a socket port check will not be done. The
127 listening flag is used the same way as in sd_is_socket(). Returns a
128 negative errno style error code on failure.
130 See sd_is_socket_inet(3) for more information.
132 int sd_is_socket_inet(int fd, int family, int type, int listening, uint16_t port);
135 Helper call for identifying a passed file descriptor. Returns 1 if the
136 file descriptor is an Internet socket of the specified type
137 (SOCK_DGRAM, SOCK_STREAM, ...), and if the address of the socket is
138 the same as the address specified by addr. The listening flag is used
139 the same way as in sd_is_socket(). Returns a negative errno style
140 error code on failure.
142 See sd_is_socket_sockaddr(3) for more information.
144 int sd_is_socket_sockaddr(int fd, int type, const struct sockaddr* addr, unsigned addr_len, int listening);
147 Helper call for identifying a passed file descriptor. Returns 1 if
148 the file descriptor is an AF_UNIX socket of the specified type
149 (SOCK_DGRAM, SOCK_STREAM, ...) and path, 0 otherwise. If type is 0
150 a socket type check will not be done. If path is NULL a socket path
151 check will not be done. For normal AF_UNIX sockets set length to
152 0. For abstract namespace sockets set length to the length of the
153 socket name (including the initial 0 byte), and pass the full
154 socket path in path (including the initial 0 byte). The listening
155 flag is used the same way as in sd_is_socket(). Returns a negative
156 errno style error code on failure.
158 See sd_is_socket_unix(3) for more information.
160 int sd_is_socket_unix(int fd, int type, int listening, const char *path, size_t length);
162 #if 0 /// UNNEEDED by elogind
164 Helper call for identifying a passed file descriptor. Returns 1 if
165 the file descriptor is a POSIX Message Queue of the specified name,
166 0 otherwise. If path is NULL a message queue name check is not
167 done. Returns a negative errno style error code on failure.
169 See sd_is_mq(3) for more information.
171 int sd_is_mq(int fd, const char *path);
175 Informs systemd about changed daemon state. This takes a number of
176 newline separated environment-style variable assignments in a
177 string. The following variables are known:
179 READY=1 Tells systemd that daemon startup is finished (only
180 relevant for services of Type=notify). The passed
181 argument is a boolean "1" or "0". Since there is
182 little value in signaling non-readiness the only
183 value daemons should send is "READY=1".
185 STATUS=... Passes a single-line status string back to systemd
186 that describes the daemon state. This is free-form
187 and can be used for various purposes: general state
188 feedback, fsck-like programs could pass completion
189 percentages and failing programs could pass a human
190 readable error message. Example: "STATUS=Completed
191 66% of file system check..."
193 ERRNO=... If a daemon fails, the errno-style error code,
194 formatted as string. Example: "ERRNO=2" for ENOENT.
196 BUSERROR=... If a daemon fails, the D-Bus error-style error
197 code. Example: "BUSERROR=org.freedesktop.DBus.Error.TimedOut"
199 MAINPID=... The main pid of a daemon, in case systemd did not
200 fork off the process itself. Example: "MAINPID=4711"
202 WATCHDOG=1 Tells systemd to update the watchdog timestamp.
203 Services using this feature should do this in
204 regular intervals. A watchdog framework can use the
205 timestamps to detect failed services. Also see
206 sd_watchdog_enabled() below.
208 FDSTORE=1 Store the file descriptors passed along with the
209 message in the per-service file descriptor store,
210 and pass them to the main process again on next
211 invocation. This variable is only supported with
212 sd_pid_notify_with_fds().
215 Reset watchdog_usec value during runtime.
216 To reset watchdog_usec value, start the service again.
217 Example: "WATCHDOG_USEC=20000000"
219 Daemons can choose to send additional variables. However, it is
220 recommended to prefix variable names not listed above with X_.
222 Returns a negative errno-style error code on failure. Returns > 0
223 if systemd could be notified, 0 if it couldn't possibly because
224 systemd is not running.
226 Example: When a daemon finished starting up, it could issue this
227 call to notify systemd about it:
229 sd_notify(0, "READY=1");
231 See sd_notifyf() for more complete examples.
233 See sd_notify(3) for more information.
235 int sd_notify(int unset_environment, const char *state);
238 Similar to sd_notify() but takes a format string.
240 Example 1: A daemon could send the following after initialization:
242 sd_notifyf(0, "READY=1\n"
243 "STATUS=Processing requests...\n"
245 (unsigned long) getpid());
247 Example 2: A daemon could send the following shortly before
250 sd_notifyf(0, "STATUS=Failed to start up: %s\n"
255 See sd_notifyf(3) for more information.
257 int sd_notifyf(int unset_environment, const char *format, ...) _sd_printf_(2,3);
260 Similar to sd_notify(), but send the message on behalf of another
261 process, if the appropriate permissions are available.
263 int sd_pid_notify(pid_t pid, int unset_environment, const char *state);
266 Similar to sd_notifyf(), but send the message on behalf of another
267 process, if the appropriate permissions are available.
269 int sd_pid_notifyf(pid_t pid, int unset_environment, const char *format, ...) _sd_printf_(3,4);
272 Similar to sd_pid_notify(), but also passes the specified fd array
273 to the service manager for storage. This is particularly useful for
276 int sd_pid_notify_with_fds(pid_t pid, int unset_environment, const char *state, const int *fds, unsigned n_fds);
279 Returns > 0 if the system was booted with systemd. Returns < 0 on
280 error. Returns 0 if the system was not booted with systemd. Note
281 that all of the functions above handle non-systemd boots just
282 fine. You should NOT protect them with a call to this function. Also
283 note that this function checks whether the system, not the user
284 session is controlled by systemd. However the functions above work
285 for both user and system services.
287 See sd_booted(3) for more information.
292 Returns > 0 if the service manager expects watchdog keep-alive
293 events to be sent regularly via sd_notify(0, "WATCHDOG=1"). Returns
294 0 if it does not expect this. If the usec argument is non-NULL
295 returns the watchdog timeout in µs after which the service manager
296 will act on a process that has not sent a watchdog keep alive
297 message. This function is useful to implement services that
298 recognize automatically if they are being run under supervision of
299 systemd with WatchdogSec= set. It is recommended for clients to
300 generate keep-alive pings via sd_notify(0, "WATCHDOG=1") every half
301 of the returned time.
303 See sd_watchdog_enabled(3) for more information.
305 int sd_watchdog_enabled(int unset_environment, uint64_t *usec);
307 _SD_END_DECLARATIONS;