1 /* SPDX-License-Identifier: LGPL-2.1-or-later */ 2 #ifndef foosddaemonhfoo 3 #define foosddaemonhfoo 4 5 /*** 6 systemd is free software; you can redistribute it and/or modify it 7 under the terms of the GNU Lesser General Public License as published by 8 the Free Software Foundation; either version 2.1 of the License, or 9 (at your option) any later version. 10 11 systemd is distributed in the hope that it will be useful, but 12 WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 Lesser General Public License for more details. 15 16 You should have received a copy of the GNU Lesser General Public License 17 along with systemd; If not, see <http://www.gnu.org/licenses/>. 18 ***/ 19 20 #include <inttypes.h> 21 #include <sys/types.h> 22 #include <sys/socket.h> 23 24 #include "_sd-common.h" 25 26 _SD_BEGIN_DECLARATIONS; 27 28 /* 29 The following functionality is provided: 30 31 - Support for logging with log levels on stderr 32 - File descriptor passing for socket-based activation 33 - Daemon startup and status notification 34 - Detection of systemd boots 35 36 See sd-daemon(3) for more information. 37 */ 38 39 /* 40 Log levels for usage on stderr: 41 42 fprintf(stderr, SD_NOTICE "Hello World!\n"); 43 44 This is similar to printk() usage in the kernel. 45 */ 46 #define SD_EMERG "<0>" /* system is unusable */ 47 #define SD_ALERT "<1>" /* action must be taken immediately */ 48 #define SD_CRIT "<2>" /* critical conditions */ 49 #define SD_ERR "<3>" /* error conditions */ 50 #define SD_WARNING "<4>" /* warning conditions */ 51 #define SD_NOTICE "<5>" /* normal but significant condition */ 52 #define SD_INFO "<6>" /* informational */ 53 #define SD_DEBUG "<7>" /* debug-level messages */ 54 55 /* The first passed file descriptor is fd 3 */ 56 #define SD_LISTEN_FDS_START 3 57 58 /* 59 Returns how many file descriptors have been passed, or a negative 60 errno code on failure. Optionally, removes the $LISTEN_FDS and 61 $LISTEN_PID file descriptors from the environment (recommended, but 62 problematic in threaded environments). If r is the return value of 63 this function you'll find the file descriptors passed as fds 64 SD_LISTEN_FDS_START to SD_LISTEN_FDS_START+r-1. Returns a negative 65 errno style error code on failure. This function call ensures that 66 the FD_CLOEXEC flag is set for the passed file descriptors, to make 67 sure they are not passed on to child processes. If FD_CLOEXEC shall 68 not be set, the caller needs to unset it after this call for all file 69 descriptors that are used. 70 71 See sd_listen_fds(3) for more information. 72 */ 73 int sd_listen_fds(int unset_environment); 74 75 int sd_listen_fds_with_names(int unset_environment, char ***names); 76 77 /* 78 Helper call for identifying a passed file descriptor. Returns 1 if 79 the file descriptor is a FIFO in the file system stored under the 80 specified path, 0 otherwise. If path is NULL a path name check will 81 not be done and the call only verifies if the file descriptor 82 refers to a FIFO. Returns a negative errno style error code on 83 failure. 84 85 See sd_is_fifo(3) for more information. 86 */ 87 int sd_is_fifo(int fd, const char *path); 88 89 /* 90 Helper call for identifying a passed file descriptor. Returns 1 if 91 the file descriptor is a special character device on the file 92 system stored under the specified path, 0 otherwise. 93 If path is NULL a path name check will not be done and the call 94 only verifies if the file descriptor refers to a special character. 95 Returns a negative errno style error code on failure. 96 97 See sd_is_special(3) for more information. 98 */ 99 int sd_is_special(int fd, const char *path); 100 101 /* 102 Helper call for identifying a passed file descriptor. Returns 1 if 103 the file descriptor is a socket of the specified family (AF_INET, 104 ...) and type (SOCK_DGRAM, SOCK_STREAM, ...), 0 otherwise. If 105 family is 0 a socket family check will not be done. If type is 0 a 106 socket type check will not be done and the call only verifies if 107 the file descriptor refers to a socket. If listening is > 0 it is 108 verified that the socket is in listening mode. (i.e. listen() has 109 been called) If listening is == 0 it is verified that the socket is 110 not in listening mode. If listening is < 0 no listening mode check 111 is done. Returns a negative errno style error code on failure. 112 113 See sd_is_socket(3) for more information. 114 */ 115 int sd_is_socket(int fd, int family, int type, int listening); 116 117 /* 118 Helper call for identifying a passed file descriptor. Returns 1 if 119 the file descriptor is an Internet socket, of the specified family 120 (either AF_INET or AF_INET6) and the specified type (SOCK_DGRAM, 121 SOCK_STREAM, ...), 0 otherwise. If version is 0 a protocol version 122 check is not done. If type is 0 a socket type check will not be 123 done. If port is 0 a socket port check will not be done. The 124 listening flag is used the same way as in sd_is_socket(). Returns a 125 negative errno style error code on failure. 126 127 See sd_is_socket_inet(3) for more information. 128 */ 129 int sd_is_socket_inet(int fd, int family, int type, int listening, uint16_t port); 130 131 /* 132 Helper call for identifying a passed file descriptor. Returns 1 if the 133 file descriptor is an Internet socket of the specified type 134 (SOCK_DGRAM, SOCK_STREAM, ...), and if the address of the socket is 135 the same as the address specified by addr. The listening flag is used 136 the same way as in sd_is_socket(). Returns a negative errno style 137 error code on failure. 138 139 See sd_is_socket_sockaddr(3) for more information. 140 */ 141 int sd_is_socket_sockaddr(int fd, int type, const struct sockaddr* addr, unsigned addr_len, int listening); 142 143 /* 144 Helper call for identifying a passed file descriptor. Returns 1 if 145 the file descriptor is an AF_UNIX socket of the specified type 146 (SOCK_DGRAM, SOCK_STREAM, ...) and path, 0 otherwise. If type is 0 147 a socket type check will not be done. If path is NULL a socket path 148 check will not be done. For normal AF_UNIX sockets set length to 149 0. For abstract namespace sockets set length to the length of the 150 socket name (including the initial 0 byte), and pass the full 151 socket path in path (including the initial 0 byte). The listening 152 flag is used the same way as in sd_is_socket(). Returns a negative 153 errno style error code on failure. 154 155 See sd_is_socket_unix(3) for more information. 156 */ 157 int sd_is_socket_unix(int fd, int type, int listening, const char *path, size_t length); 158 159 /* 160 Helper call for identifying a passed file descriptor. Returns 1 if 161 the file descriptor is a POSIX Message Queue of the specified name, 162 0 otherwise. If path is NULL a message queue name check is not 163 done. Returns a negative errno style error code on failure. 164 165 See sd_is_mq(3) for more information. 166 */ 167 int sd_is_mq(int fd, const char *path); 168 169 /* 170 Informs systemd about changed daemon state. This takes a number of 171 newline separated environment-style variable assignments in a 172 string. The following variables are known: 173 174 MAINPID=... The main PID of a daemon, in case systemd did not 175 fork off the process itself. Example: "MAINPID=4711" 176 177 READY=1 Tells systemd that daemon startup or daemon reload 178 is finished (only relevant for services of Type=notify). 179 The passed argument is a boolean "1" or "0". Since there 180 is little value in signaling non-readiness the only 181 value daemons should send is "READY=1". 182 183 RELOADING=1 Tell systemd that the daemon began reloading its 184 configuration. When the configuration has been 185 reloaded completely, READY=1 should be sent to inform 186 systemd about this. 187 188 STOPPING=1 Tells systemd that the daemon is about to go down. 189 190 STATUS=... Passes a single-line status string back to systemd 191 that describes the daemon state. This is free-form 192 and can be used for various purposes: general state 193 feedback, fsck-like programs could pass completion 194 percentages and failing programs could pass a human 195 readable error message. Example: "STATUS=Completed 196 66% of file system check..." 197 198 ERRNO=... If a daemon fails, the errno-style error code, 199 formatted as string. Example: "ERRNO=2" for ENOENT. 200 201 BUSERROR=... If a daemon fails, the D-Bus error-style error 202 code. Example: "BUSERROR=org.freedesktop.DBus.Error.TimedOut" 203 204 WATCHDOG=1 Tells systemd to update the watchdog timestamp. 205 Services using this feature should do this in 206 regular intervals. A watchdog framework can use the 207 timestamps to detect failed services. Also see 208 sd_watchdog_enabled() below. 209 210 WATCHDOG_USEC=... 211 Reset watchdog_usec value during runtime. 212 To reset watchdog_usec value, start the service again. 213 Example: "WATCHDOG_USEC=20000000" 214 215 FDSTORE=1 Store the file descriptors passed along with the 216 message in the per-service file descriptor store, 217 and pass them to the main process again on next 218 invocation. This variable is only supported with 219 sd_pid_notify_with_fds(). 220 221 FDSTOREREMOVE=1 222 Remove one or more file descriptors from the file 223 descriptor store, identified by the name specified 224 in FDNAME=, see below. 225 226 FDNAME= A name to assign to new file descriptors stored in the 227 file descriptor store, or the name of the file descriptors 228 to remove in case of FDSTOREREMOVE=1. 229 230 Daemons can choose to send additional variables. However, it is 231 recommended to prefix variable names not listed above with X_. 232 233 Returns a negative errno-style error code on failure. Returns > 0 234 if systemd could be notified, 0 if it couldn't possibly because 235 systemd is not running. 236 237 Example: When a daemon finished starting up, it could issue this 238 call to notify systemd about it: 239 240 sd_notify(0, "READY=1"); 241 242 See sd_notifyf() for more complete examples. 243 244 See sd_notify(3) for more information. 245 */ 246 int sd_notify(int unset_environment, const char *state); 247 248 /* 249 Similar to sd_notify() but takes a format string. 250 251 Example 1: A daemon could send the following after initialization: 252 253 sd_notifyf(0, "READY=1\n" 254 "STATUS=Processing requests...\n" 255 "MAINPID=%lu", 256 (unsigned long) getpid()); 257 258 Example 2: A daemon could send the following shortly before 259 exiting, on failure: 260 261 sd_notifyf(0, "STATUS=Failed to start up: %s\n" 262 "ERRNO=%i", 263 strerror(errno), 264 errno); 265 266 See sd_notifyf(3) for more information. 267 */ 268 int sd_notifyf(int unset_environment, const char *format, ...) _sd_printf_(2,3); 269 270 /* 271 Similar to sd_notify(), but send the message on behalf of another 272 process, if the appropriate permissions are available. 273 */ 274 int sd_pid_notify(pid_t pid, int unset_environment, const char *state); 275 276 /* 277 Similar to sd_notifyf(), but send the message on behalf of another 278 process, if the appropriate permissions are available. 279 */ 280 int sd_pid_notifyf(pid_t pid, int unset_environment, const char *format, ...) _sd_printf_(3,4); 281 282 /* 283 Similar to sd_pid_notify(), but also passes the specified fd array 284 to the service manager for storage. This is particularly useful for 285 FDSTORE=1 messages. 286 */ 287 int sd_pid_notify_with_fds(pid_t pid, int unset_environment, const char *state, const int *fds, unsigned n_fds); 288 289 /* 290 Returns > 0 if synchronization with systemd succeeded. Returns < 0 291 on error. Returns 0 if $NOTIFY_SOCKET was not set. Note that the 292 timeout parameter of this function call takes the timeout in µs, and 293 will be passed to ppoll(2), hence the behaviour will be similar to 294 ppoll(2). This function can be called after sending a status message 295 to systemd, if one needs to synchronize against reception of the 296 status messages sent before this call is made. Therefore, this 297 cannot be used to know if the status message was processed 298 successfully, but to only synchronize against its consumption. 299 */ 300 int sd_notify_barrier(int unset_environment, uint64_t timeout); 301 302 /* 303 Returns > 0 if the system was booted with systemd. Returns < 0 on 304 error. Returns 0 if the system was not booted with systemd. Note 305 that all of the functions above handle non-systemd boots just 306 fine. You should NOT protect them with a call to this function. Also 307 note that this function checks whether the system, not the user 308 session is controlled by systemd. However the functions above work 309 for both user and system services. 310 311 See sd_booted(3) for more information. 312 */ 313 int sd_booted(void); 314 315 /* 316 Returns > 0 if the service manager expects watchdog keep-alive 317 events to be sent regularly via sd_notify(0, "WATCHDOG=1"). Returns 318 0 if it does not expect this. If the usec argument is non-NULL 319 returns the watchdog timeout in µs after which the service manager 320 will act on a process that has not sent a watchdog keep alive 321 message. This function is useful to implement services that 322 recognize automatically if they are being run under supervision of 323 systemd with WatchdogSec= set. It is recommended for clients to 324 generate keep-alive pings via sd_notify(0, "WATCHDOG=1") every half 325 of the returned time. 326 327 See sd_watchdog_enabled(3) for more information. 328 */ 329 int sd_watchdog_enabled(int unset_environment, uint64_t *usec); 330 331 _SD_END_DECLARATIONS; 332 333 #endif 334