diff options
| -rw-r--r-- | src/macro.h | 2 | ||||
| -rw-r--r-- | src/sd-daemon.c | 20 | ||||
| -rw-r--r-- | src/sd-daemon.h | 291 |
3 files changed, 194 insertions, 119 deletions
diff --git a/src/macro.h b/src/macro.h index 763a4de27a..d00e70bf6d 100644 --- a/src/macro.h +++ b/src/macro.h @@ -38,6 +38,8 @@ #define _weak_ __attribute__ ((weak)) #define _likely_(x) (__builtin_expect(!!(x),1)) #define _unlikely_(x) (__builtin_expect(!!(x),0)) +#define _public_ __attribute__ ((visibility("default"))) +#define _hidden_ __attribute__ ((visibility("hidden"))) /* Rounds up */ static inline size_t ALIGN(size_t l) { diff --git a/src/sd-daemon.c b/src/sd-daemon.c index e6b9a6f3c2..cb568b5e65 100644 --- a/src/sd-daemon.c +++ b/src/sd-daemon.c @@ -426,3 +426,23 @@ int sd_notifyf(int unset_environment, const char *format, ...) { return r; #endif } + +int sd_booted(void) { +#if defined(DISABLE_SYSTEMD) || !defined(__linux__) + return 0; +#else + + struct stat a, b; + + /* We simply test whether the systemd cgroup hierarchy is + * mounted */ + + if (lstat("/cgroup", &a) < 0) + return 0; + + if (lstat("/cgroup/systemd", &b) < 0) + return 0; + + return a.st_dev != b.st_dev; +#endif +} diff --git a/src/sd-daemon.h b/src/sd-daemon.h index 20c260c40d..dc18f42eaa 100644 --- a/src/sd-daemon.h +++ b/src/sd-daemon.h @@ -34,17 +34,43 @@ 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. */ - -#ifdef __GNUC__ +/* + 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 make 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. +*/ + +#if __GNUC__ >= 4 #define _sd_printf_attr_(a,b) __attribute__ ((format (printf, a, b))) +#define _sd_hidden_ __attribute__ ((visibility("hidden"))) #else #define _sd_printf_attr_(a,b) +#define _sd_hidden_ #endif /* @@ -54,7 +80,6 @@ extern "C" { 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 */ @@ -67,116 +92,144 @@ extern "C" { /* 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.*/ -int sd_listen_fds(int unset_environment); - -/* 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. */ -int sd_is_fifo(int fd, const char *path); - -/* 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. */ -int sd_is_socket(int fd, int family, int type, int listening); - -/* 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. */ -int sd_is_socket_inet(int fd, int family, int type, int listening, uint16_t port); - -/* 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. */ -int sd_is_socket_unix(int fd, int type, int listening, const char *path, size_t length); - -/* Informs systemd about changed daemon state. This takes a numeber of - * newline seperated environment-style variable assignments in a - * string. The following strings 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. - * - * 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. - * - * See sd_notifyf() for more complete examples. - */ -int sd_notify(int unset_environment, const char *state); - -/* Similar to sd_send_state() 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); - */ -int sd_notifyf(int unset_environment, const char *format, ...) _sd_printf_attr_(2,3); +/* + 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. +*/ +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. +*/ +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. +*/ +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. +*/ +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. +*/ +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 numeber of + newline seperated environment-style variable assignments in a + string. The following strings 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. + + 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. +*/ +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); +*/ +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. +*/ +int sd_booted(void) _sd_hidden_; #ifdef __cplusplus } |