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 #if 0 /// UNNEEDED by elogind
64 Returns how many file descriptors have been passed, or a negative
65 errno code on failure. Optionally, removes the $LISTEN_FDS and
66 $LISTEN_PID file descriptors from the environment (recommended, but
67 problematic in threaded environments). If r is the return value of
68 this function you'll find the file descriptors passed as fds
69 SD_LISTEN_FDS_START to SD_LISTEN_FDS_START+r-1. Returns a negative
70 errno style error code on failure. This function call ensures that
71 the FD_CLOEXEC flag is set for the passed file descriptors, to make
72 sure they are not passed on to child processes. If FD_CLOEXEC shall
73 not be set, the caller needs to unset it after this call for all file
74 descriptors that are used.
76 See sd_listen_fds(3) for more information.
78 int sd_listen_fds(int unset_environment);
80 int sd_listen_fds_with_names(int unset_environment, char ***names);
83 Helper call for identifying a passed file descriptor. Returns 1 if
84 the file descriptor is a FIFO in the file system stored under the
85 specified path, 0 otherwise. If path is NULL a path name check will
86 not be done and the call only verifies if the file descriptor
87 refers to a FIFO. Returns a negative errno style error code on
90 See sd_is_fifo(3) for more information.
92 int sd_is_fifo(int fd, const char *path);
95 Helper call for identifying a passed file descriptor. Returns 1 if
96 the file descriptor is a special character device on the file
97 system stored under the specified path, 0 otherwise.
98 If path is NULL a path name check will not be done and the call
99 only verifies if the file descriptor refers to a special character.
100 Returns a negative errno style error code on failure.
102 See sd_is_special(3) for more information.
104 int sd_is_special(int fd, const char *path);
108 Helper call for identifying a passed file descriptor. Returns 1 if
109 the file descriptor is a socket of the specified family (AF_INET,
110 ...) and type (SOCK_DGRAM, SOCK_STREAM, ...), 0 otherwise. If
111 family is 0 a socket family check will not be done. If type is 0 a
112 socket type check will not be done and the call only verifies if
113 the file descriptor refers to a socket. If listening is > 0 it is
114 verified that the socket is in listening mode. (i.e. listen() has
115 been called) If listening is == 0 it is verified that the socket is
116 not in listening mode. If listening is < 0 no listening mode check
117 is done. Returns a negative errno style error code on failure.
119 See sd_is_socket(3) for more information.
121 int sd_is_socket(int fd, int family, int type, int listening);
123 #if 0 /// UNNEEDED by elogind
125 Helper call for identifying a passed file descriptor. Returns 1 if
126 the file descriptor is an Internet socket, of the specified family
127 (either AF_INET or AF_INET6) and the specified type (SOCK_DGRAM,
128 SOCK_STREAM, ...), 0 otherwise. If version is 0 a protocol version
129 check is not done. If type is 0 a socket type check will not be
130 done. If port is 0 a socket port check will not be done. The
131 listening flag is used the same way as in sd_is_socket(). Returns a
132 negative errno style error code on failure.
134 See sd_is_socket_inet(3) for more information.
136 int sd_is_socket_inet(int fd, int family, int type, int listening, uint16_t port);
139 Helper call for identifying a passed file descriptor. Returns 1 if
140 the file descriptor is an AF_UNIX socket of the specified type
141 (SOCK_DGRAM, SOCK_STREAM, ...) and path, 0 otherwise. If type is 0
142 a socket type check will not be done. If path is NULL a socket path
143 check will not be done. For normal AF_UNIX sockets set length to
144 0. For abstract namespace sockets set length to the length of the
145 socket name (including the initial 0 byte), and pass the full
146 socket path in path (including the initial 0 byte). The listening
147 flag is used the same way as in sd_is_socket(). Returns a negative
148 errno style error code on failure.
150 See sd_is_socket_unix(3) for more information.
152 int sd_is_socket_unix(int fd, int type, int listening, const char *path, size_t length);
155 Helper call for identifying a passed file descriptor. Returns 1 if
156 the file descriptor is a POSIX Message Queue of the specified name,
157 0 otherwise. If path is NULL a message queue name check is not
158 done. Returns a negative errno style error code on failure.
160 See sd_is_mq(3) for more information.
162 int sd_is_mq(int fd, const char *path);
166 Informs systemd about changed daemon state. This takes a number of
167 newline separated environment-style variable assignments in a
168 string. The following variables are known:
170 READY=1 Tells systemd that daemon startup is finished (only
171 relevant for services of Type=notify). The passed
172 argument is a boolean "1" or "0". Since there is
173 little value in signaling non-readiness the only
174 value daemons should send is "READY=1".
176 STATUS=... Passes a single-line status string back to systemd
177 that describes the daemon state. This is free-form
178 and can be used for various purposes: general state
179 feedback, fsck-like programs could pass completion
180 percentages and failing programs could pass a human
181 readable error message. Example: "STATUS=Completed
182 66% of file system check..."
184 ERRNO=... If a daemon fails, the errno-style error code,
185 formatted as string. Example: "ERRNO=2" for ENOENT.
187 BUSERROR=... If a daemon fails, the D-Bus error-style error
188 code. Example: "BUSERROR=org.freedesktop.DBus.Error.TimedOut"
190 MAINPID=... The main pid of a daemon, in case systemd did not
191 fork off the process itself. Example: "MAINPID=4711"
193 WATCHDOG=1 Tells systemd to update the watchdog timestamp.
194 Services using this feature should do this in
195 regular intervals. A watchdog framework can use the
196 timestamps to detect failed services. Also see
197 sd_watchdog_enabled() below.
199 FDSTORE=1 Store the file descriptors passed along with the
200 message in the per-service file descriptor store,
201 and pass them to the main process again on next
202 invocation. This variable is only supported with
203 sd_pid_notify_with_fds().
205 Daemons can choose to send additional variables. However, it is
206 recommended to prefix variable names not listed above with X_.
208 Returns a negative errno-style error code on failure. Returns > 0
209 if systemd could be notified, 0 if it couldn't possibly because
210 systemd is not running.
212 Example: When a daemon finished starting up, it could issue this
213 call to notify systemd about it:
215 sd_notify(0, "READY=1");
217 See sd_notifyf() for more complete examples.
219 See sd_notify(3) for more information.
221 int sd_notify(int unset_environment, const char *state);
223 #if 0 /// UNNEEDED by elogind
225 Similar to sd_notify() but takes a format string.
227 Example 1: A daemon could send the following after initialization:
229 sd_notifyf(0, "READY=1\n"
230 "STATUS=Processing requests...\n"
232 (unsigned long) getpid());
234 Example 2: A daemon could send the following shortly before
237 sd_notifyf(0, "STATUS=Failed to start up: %s\n"
242 See sd_notifyf(3) for more information.
244 int sd_notifyf(int unset_environment, const char *format, ...) _sd_printf_(2,3);
247 Similar to sd_notify(), but send the message on behalf of another
248 process, if the appropriate permissions are available.
250 int sd_pid_notify(pid_t pid, int unset_environment, const char *state);
253 Similar to sd_notifyf(), but send the message on behalf of another
254 process, if the appropriate permissions are available.
256 int sd_pid_notifyf(pid_t pid, int unset_environment, const char *format, ...) _sd_printf_(3,4);
260 Similar to sd_pid_notify(), but also passes the specified fd array
261 to the service manager for storage. This is particularly useful for
264 int sd_pid_notify_with_fds(pid_t pid, int unset_environment, const char *state, const int *fds, unsigned n_fds);
266 #if 0 /// UNNEEDED by elogind
268 Returns > 0 if the system was booted with systemd. Returns < 0 on
269 error. Returns 0 if the system was not booted with systemd. Note
270 that all of the functions above handle non-systemd boots just
271 fine. You should NOT protect them with a call to this function. Also
272 note that this function checks whether the system, not the user
273 session is controlled by systemd. However the functions above work
274 for both user and system services.
276 See sd_booted(3) for more information.
282 Returns > 0 if the service manager expects watchdog keep-alive
283 events to be sent regularly via sd_notify(0, "WATCHDOG=1"). Returns
284 0 if it does not expect this. If the usec argument is non-NULL
285 returns the watchdog timeout in µs after which the service manager
286 will act on a process that has not sent a watchdog keep alive
287 message. This function is useful to implement services that
288 recognize automatically if they are being run under supervision of
289 systemd with WatchdogSec= set. It is recommended for clients to
290 generate keep-alive pings via sd_notify(0, "WATCHDOG=1") every half
291 of the returned time.
293 See sd_watchdog_enabled(3) for more information.
295 int sd_watchdog_enabled(int unset_environment, uint64_t *usec);
297 _SD_END_DECLARATIONS;