1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ 2 3 #ifndef foosddaemonhfoo 4 #define foosddaemonhfoo 5 6 /*** 7 Copyright 2010 Lennart Poettering 8 9 Permission is hereby granted, free of charge, to any person 10 obtaining a copy of this software and associated documentation files 11 (the "Software"), to deal in the Software without restriction, 12 including without limitation the rights to use, copy, modify, merge, 13 publish, distribute, sublicense, and/or sell copies of the Software, 14 and to permit persons to whom the Software is furnished to do so, 15 subject to the following conditions: 16 17 The above copyright notice and this permission notice shall be 18 included in all copies or substantial portions of the Software. 19 20 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 21 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 22 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 23 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS 24 BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN 25 ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 26 CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 27 SOFTWARE. 28 ***/ 29 30 #include <sys/types.h> 31 #include <inttypes.h> 32 33 #ifdef __cplusplus 34 extern "C" { 35 #endif 36 37 /* 38 Reference implementation of a few systemd related interfaces for 39 writing daemons. These interfaces are trivial to implement. To 40 simplify porting we provide this reference implementation. 41 Applications are welcome to reimplement the algorithms described 42 here if they do not want to include these two source files. 43 44 The following functionality is provided: 45 46 - Support for logging with log levels on stderr 47 - File descriptor passing for socket-based activation 48 - Daemon startup and status notification 49 - Detection of systemd boots 50 51 You may compile this with -DDISABLE_SYSTEMD to disable systemd 52 support. This makes all those calls NOPs that are directly related to 53 systemd (i.e. only sd_is_xxx() will stay useful). 54 55 Since this is drop-in code we don't want any of our symbols to be 56 exported in any case. Hence we declare hidden visibility for all of 57 them. 58 59 You may find an up-to-date version of these source files online: 60 61 http://cgit.freedesktop.org/systemd/plain/src/sd-daemon.h 62 http://cgit.freedesktop.org/systemd/plain/src/sd-daemon.c 63 64 This should compile on non-Linux systems, too, but with the 65 exception of the sd_is_xxx() calls all functions will become NOPs. 66 67 See sd-daemon(7) for more information. 68 */ 69 70 #ifndef _sd_printf_attr_ 71 #if __GNUC__ >= 4 72 #define _sd_printf_attr_(a,b) __attribute__ ((format (printf, a, b))) 73 #else 74 #define _sd_printf_attr_(a,b) 75 #endif 76 #endif 77 78 #ifndef _sd_hidden_ 79 #if (__GNUC__ >= 4) && !defined(SD_EXPORT_SYMBOLS) 80 #define _sd_hidden_ __attribute__ ((visibility("hidden"))) 81 #else 82 #define _sd_hidden_ 83 #endif 84 #endif 85 86 /* 87 Log levels for usage on stderr: 88 89 fprintf(stderr, SD_NOTICE "Hello World!\n"); 90 91 This is similar to printk() usage in the kernel. 92 */ 93 #define SD_EMERG "<0>" /* system is unusable */ 94 #define SD_ALERT "<1>" /* action must be taken immediately */ 95 #define SD_CRIT "<2>" /* critical conditions */ 96 #define SD_ERR "<3>" /* error conditions */ 97 #define SD_WARNING "<4>" /* warning conditions */ 98 #define SD_NOTICE "<5>" /* normal but significant condition */ 99 #define SD_INFO "<6>" /* informational */ 100 #define SD_DEBUG "<7>" /* debug-level messages */ 101 102 /* The first passed file descriptor is fd 3 */ 103 #define SD_LISTEN_FDS_START 3 104 105 /* 106 Returns how many file descriptors have been passed, or a negative 107 errno code on failure. Optionally, removes the $LISTEN_FDS and 108 $LISTEN_PID file descriptors from the environment (recommended, but 109 problematic in threaded environments). If r is the return value of 110 this function you'll find the file descriptors passed as fds 111 SD_LISTEN_FDS_START to SD_LISTEN_FDS_START+r-1. Returns a negative 112 errno style error code on failure. This function call ensures that 113 the FD_CLOEXEC flag is set for the passed file descriptors, to make 114 sure they are not passed on to child processes. If FD_CLOEXEC shall 115 not be set, the caller needs to unset it after this call for all file 116 descriptors that are used. 117 118 See sd_listen_fds(3) for more information. 119 */ 120 int sd_listen_fds(int unset_environment) _sd_hidden_; 121 122 /* 123 Helper call for identifying a passed file descriptor. Returns 1 if 124 the file descriptor is a FIFO in the file system stored under the 125 specified path, 0 otherwise. If path is NULL a path name check will 126 not be done and the call only verifies if the file descriptor 127 refers to a FIFO. Returns a negative errno style error code on 128 failure. 129 130 See sd_is_fifo(3) for more information. 131 */ 132 int sd_is_fifo(int fd, const char *path) _sd_hidden_; 133 134 /* 135 Helper call for identifying a passed file descriptor. Returns 1 if 136 the file descriptor is a socket of the specified family (AF_INET, 137 ...) and type (SOCK_DGRAM, SOCK_STREAM, ...), 0 otherwise. If 138 family is 0 a socket family check will not be done. If type is 0 a 139 socket type check will not be done and the call only verifies if 140 the file descriptor refers to a socket. If listening is > 0 it is 141 verified that the socket is in listening mode. (i.e. listen() has 142 been called) If listening is == 0 it is verified that the socket is 143 not in listening mode. If listening is < 0 no listening mode check 144 is done. Returns a negative errno style error code on failure. 145 146 See sd_is_socket(3) for more information. 147 */ 148 int sd_is_socket(int fd, int family, int type, int listening) _sd_hidden_; 149 150 /* 151 Helper call for identifying a passed file descriptor. Returns 1 if 152 the file descriptor is an Internet socket, of the specified family 153 (either AF_INET or AF_INET6) and the specified type (SOCK_DGRAM, 154 SOCK_STREAM, ...), 0 otherwise. If version is 0 a protocol version 155 check is not done. If type is 0 a socket type check will not be 156 done. If port is 0 a socket port check will not be done. The 157 listening flag is used the same way as in sd_is_socket(). Returns a 158 negative errno style error code on failure. 159 160 See sd_is_socket_inet(3) for more information. 161 */ 162 int sd_is_socket_inet(int fd, int family, int type, int listening, uint16_t port) _sd_hidden_; 163 164 /* 165 Helper call for identifying a passed file descriptor. Returns 1 if 166 the file descriptor is an AF_UNIX socket of the specified type 167 (SOCK_DGRAM, SOCK_STREAM, ...) and path, 0 otherwise. If type is 0 168 a socket type check will not be done. If path is NULL a socket path 169 check will not be done. For normal AF_UNIX sockets set length to 170 0. For abstract namespace sockets set length to the length of the 171 socket name (including the initial 0 byte), and pass the full 172 socket path in path (including the initial 0 byte). The listening 173 flag is used the same way as in sd_is_socket(). Returns a negative 174 errno style error code on failure. 175 176 See sd_is_socket_unix(3) for more information. 177 */ 178 int sd_is_socket_unix(int fd, int type, int listening, const char *path, size_t length) _sd_hidden_; 179 180 /* 181 Informs systemd about changed daemon state. This takes a number of 182 newline separated environment-style variable assignments in a 183 string. The following variables are known: 184 185 READY=1 Tells systemd that daemon startup is finished (only 186 relevant for services of Type=notify). The passed 187 argument is a boolean "1" or "0". Since there is 188 little value in signaling non-readiness the only 189 value daemons should send is "READY=1". 190 191 STATUS=... Passes a single-line status string back to systemd 192 that describes the daemon state. This is free-from 193 and can be used for various purposes: general state 194 feedback, fsck-like programs could pass completion 195 percentages and failing programs could pass a human 196 readable error message. Example: "STATUS=Completed 197 66% of file system check..." 198 199 ERRNO=... If a daemon fails, the errno-style error code, 200 formatted as string. Example: "ERRNO=2" for ENOENT. 201 202 BUSERROR=... If a daemon fails, the D-Bus error-style error 203 code. Example: "BUSERROR=org.freedesktop.DBus.Error.TimedOut" 204 205 MAINPID=... The main pid of a daemon, in case systemd did not 206 fork off the process itself. Example: "MAINPID=4711" 207 208 Daemons can choose to send additional variables. However, it is 209 recommended to prefix variable names not listed above with X_. 210 211 Returns a negative errno-style error code on failure. Returns > 0 212 if systemd could be notified, 0 if it couldn't possibly because 213 systemd is not running. 214 215 Example: When a daemon finished starting up, it could issue this 216 call to notify systemd about it: 217 218 sd_notify(0, "READY=1"); 219 220 See sd_notifyf() for more complete examples. 221 222 See sd_notify(3) for more information. 223 */ 224 int sd_notify(int unset_environment, const char *state) _sd_hidden_; 225 226 /* 227 Similar to sd_notify() but takes a format string. 228 229 Example 1: A daemon could send the following after initialization: 230 231 sd_notifyf(0, "READY=1\n" 232 "STATUS=Processing requests...\n" 233 "MAINPID=%lu", 234 (unsigned long) getpid()); 235 236 Example 2: A daemon could send the following shortly before 237 exiting, on failure: 238 239 sd_notifyf(0, "STATUS=Failed to start up: %s\n" 240 "ERRNO=%i", 241 strerror(errno), 242 errno); 243 244 See sd_notifyf(3) for more information. 245 */ 246 int sd_notifyf(int unset_environment, const char *format, ...) _sd_printf_attr_(2,3) _sd_hidden_; 247 248 /* 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. 256 257 See sd_booted(3) for more information. 258 */ 259 int sd_booted(void) _sd_hidden_; 260 261 #ifdef __cplusplus 262 } 263 #endif 264 265 #endif 266
