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Diffstat (limited to 'udev/sd-daemon.h')
| -rw-r--r-- | udev/sd-daemon.h | 265 |
1 files changed, 265 insertions, 0 deletions
diff --git a/udev/sd-daemon.h b/udev/sd-daemon.h new file mode 100644 index 0000000000..fdf3cc0354 --- /dev/null +++ b/udev/sd-daemon.h @@ -0,0 +1,265 @@ +/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ + +#ifndef foosddaemonhfoo +#define foosddaemonhfoo + +/*** + Copyright 2010 Lennart Poettering + + Permission is hereby granted, free of charge, to any person + obtaining a copy of this software and associated documentation files + (the "Software"), to deal in the Software without restriction, + including without limitation the rights to use, copy, modify, merge, + publish, distribute, sublicense, and/or sell copies of the Software, + and to permit persons to whom the Software is furnished to do so, + subject to the following conditions: + + The above copyright notice and this permission notice shall be + included in all copies or substantial portions of the Software. + + THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS + BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN + ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + SOFTWARE. +***/ + +#include <sys/types.h> +#include <inttypes.h> + +#ifdef __cplusplus +extern "C" { +#endif + +/* + Reference implementation of a few systemd related interfaces for + writing daemons. These interfaces are trivial to implement. To + simplify porting we provide this reference implementation. + Applications are welcome to reimplement the algorithms described + here if they do not want to include these two source files. + + The following functionality is provided: + + - Support for logging with log levels on stderr + - File descriptor passing for socket-based activation + - Daemon startup and status notification + - Detection of systemd boots + + You may compile this with -DDISABLE_SYSTEMD to disable systemd + support. This makes all those calls NOPs that are directly related to + systemd (i.e. only sd_is_xxx() will stay useful). + + Since this is drop-in code we don't want any of our symbols to be + exported in any case. Hence we declare hidden visibility for all of + them. + + You may find an up-to-date version of these source files online: + + http://cgit.freedesktop.org/systemd/plain/src/sd-daemon.h + http://cgit.freedesktop.org/systemd/plain/src/sd-daemon.c + + This should compile on non-Linux systems, too, but with the + exception of the sd_is_xxx() calls all functions will become NOPs. + + See sd-daemon(7) for more information. +*/ + +#ifndef _sd_printf_attr_ +#if __GNUC__ >= 4 +#define _sd_printf_attr_(a,b) __attribute__ ((format (printf, a, b))) +#else +#define _sd_printf_attr_(a,b) +#endif +#endif + +#ifndef _sd_hidden_ +#if (__GNUC__ >= 4) && !defined(SD_EXPORT_SYMBOLS) +#define _sd_hidden_ __attribute__ ((visibility("hidden"))) +#else +#define _sd_hidden_ +#endif +#endif + +/* + Log levels for usage on stderr: + + fprintf(stderr, SD_NOTICE "Hello World!\n"); + + This is similar to printk() usage in the kernel. +*/ +#define SD_EMERG "<0>" /* system is unusable */ +#define SD_ALERT "<1>" /* action must be taken immediately */ +#define SD_CRIT "<2>" /* critical conditions */ +#define SD_ERR "<3>" /* error conditions */ +#define SD_WARNING "<4>" /* warning conditions */ +#define SD_NOTICE "<5>" /* normal but significant condition */ +#define SD_INFO "<6>" /* informational */ +#define SD_DEBUG "<7>" /* debug-level messages */ + +/* The first passed file descriptor is fd 3 */ +#define SD_LISTEN_FDS_START 3 + +/* + Returns how many file descriptors have been passed, or a negative + errno code on failure. Optionally, removes the $LISTEN_FDS and + $LISTEN_PID file descriptors from the environment (recommended, but + problematic in threaded environments). If r is the return value of + this function you'll find the file descriptors passed as fds + SD_LISTEN_FDS_START to SD_LISTEN_FDS_START+r-1. Returns a negative + errno style error code on failure. This function call ensures that + the FD_CLOEXEC flag is set for the passed file descriptors, to make + sure they are not passed on to child processes. If FD_CLOEXEC shall + not be set, the caller needs to unset it after this call for all file + descriptors that are used. + + See sd_listen_fds(3) for more information. +*/ +int sd_listen_fds(int unset_environment) _sd_hidden_; + +/* + Helper call for identifying a passed file descriptor. Returns 1 if + the file descriptor is a FIFO in the file system stored under the + specified path, 0 otherwise. If path is NULL a path name check will + not be done and the call only verifies if the file descriptor + refers to a FIFO. Returns a negative errno style error code on + failure. + + See sd_is_fifo(3) for more information. +*/ +int sd_is_fifo(int fd, const char *path) _sd_hidden_; + +/* + Helper call for identifying a passed file descriptor. Returns 1 if + the file descriptor is a socket of the specified family (AF_INET, + ...) and type (SOCK_DGRAM, SOCK_STREAM, ...), 0 otherwise. If + family is 0 a socket family check will not be done. If type is 0 a + socket type check will not be done and the call only verifies if + the file descriptor refers to a socket. If listening is > 0 it is + verified that the socket is in listening mode. (i.e. listen() has + been called) If listening is == 0 it is verified that the socket is + not in listening mode. If listening is < 0 no listening mode check + is done. Returns a negative errno style error code on failure. + + See sd_is_socket(3) for more information. +*/ +int sd_is_socket(int fd, int family, int type, int listening) _sd_hidden_; + +/* + Helper call for identifying a passed file descriptor. Returns 1 if + the file descriptor is an Internet socket, of the specified family + (either AF_INET or AF_INET6) and the specified type (SOCK_DGRAM, + SOCK_STREAM, ...), 0 otherwise. If version is 0 a protocol version + check is not done. If type is 0 a socket type check will not be + done. If port is 0 a socket port check will not be done. The + listening flag is used the same way as in sd_is_socket(). Returns a + negative errno style error code on failure. + + See sd_is_socket_inet(3) for more information. +*/ +int sd_is_socket_inet(int fd, int family, int type, int listening, uint16_t port) _sd_hidden_; + +/* + Helper call for identifying a passed file descriptor. Returns 1 if + the file descriptor is an AF_UNIX socket of the specified type + (SOCK_DGRAM, SOCK_STREAM, ...) and path, 0 otherwise. If type is 0 + a socket type check will not be done. If path is NULL a socket path + check will not be done. For normal AF_UNIX sockets set length to + 0. For abstract namespace sockets set length to the length of the + socket name (including the initial 0 byte), and pass the full + socket path in path (including the initial 0 byte). The listening + flag is used the same way as in sd_is_socket(). Returns a negative + errno style error code on failure. + + See sd_is_socket_unix(3) for more information. +*/ +int sd_is_socket_unix(int fd, int type, int listening, const char *path, size_t length) _sd_hidden_; + +/* + Informs systemd about changed daemon state. This takes a number of + newline separated environment-style variable assignments in a + string. The following variables are known: + + READY=1 Tells systemd that daemon startup is finished (only + relevant for services of Type=notify). The passed + argument is a boolean "1" or "0". Since there is + little value in signalling non-readiness the only + value daemons should send is "READY=1". + + STATUS=... Passes a single-line status string back to systemd + that describes the daemon state. This is free-from + and can be used for various purposes: general state + feedback, fsck-like programs could pass completion + percentages and failing programs could pass a human + readable error message. Example: "STATUS=Completed + 66% of file system check..." + + ERRNO=... If a daemon fails, the errno-style error code, + formatted as string. Example: "ERRNO=2" for ENOENT. + + BUSERROR=... If a daemon fails, the D-Bus error-style error + code. Example: "BUSERROR=org.freedesktop.DBus.Error.TimedOut" + + MAINPID=... The main pid of a daemon, in case systemd did not + fork off the process itself. Example: "MAINPID=4711" + + Daemons can choose to send additional variables. However, it is + recommened to prefix variable names not listed above with X_. + + Returns a negative errno-style error code on failure. Returns > 0 + if systemd could be notified, 0 if it couldn't possibly because + systemd is not running. + + Example: When a daemon finished starting up, it could issue this + call to notify systemd about it: + + sd_notify(0, "READY=1"); + + See sd_notifyf() for more complete examples. + + See sd_notify(3) for more information. +*/ +int sd_notify(int unset_environment, const char *state) _sd_hidden_; + +/* + Similar to sd_notify() but takes a format string. + + Example 1: A daemon could send the following after initialization: + + sd_notifyf(0, "READY=1\n" + "STATUS=Processing requests...\n" + "MAINPID=%lu", + (unsigned long) getpid()); + + Example 2: A daemon could send the following shortly before + exiting, on failure: + + sd_notifyf(0, "STATUS=Failed to start up: %s\n" + "ERRNO=%i", + strerror(errno), + errno); + + See sd_notifyf(3) for more information. +*/ +int sd_notifyf(int unset_environment, const char *format, ...) _sd_printf_attr_(2,3) _sd_hidden_; + +/* + Returns > 0 if the system was booted with systemd. Returns < 0 on + error. Returns 0 if the system was not booted with systemd. Note + that all of the functions above handle non-systemd boots just + fine. You should NOT protect them with a call to this function. Also + note that this function checks whether the system, not the user + session is controlled by systemd. However the functions above work + for both session and system services. + + See sd_booted(3) for more information. +*/ +int sd_booted(void) _sd_hidden_; + +#ifdef __cplusplus +} +#endif + +#endif |