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