Commit 40473a70 authored by Lennart Poettering's avatar Lennart Poettering

sd-daemon: introduce sd_booted() and set ELF visibility to hidden for all symbols

parent f1c5860b
......@@ -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) {
......
......@@ -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
}
......@@ -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
}
......
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment