sd_is_fifo, sd_is_socket, sd_is_socket_inet, sd_is_socket_unix, sd_is_mq, sd_is_special — Check the type of a file descriptor
#include <systemd/sd-daemon.h>
int sd_is_fifo( | int fd, |
const char *path); |
int sd_is_socket( | int fd, |
| int family, | |
| int type, | |
int listening); |
int sd_is_socket_inet( | int fd, |
| int family, | |
| int type, | |
| int listening, | |
uint16_t port); |
int sd_is_socket_unix( | int fd, |
| int type, | |
| int listening, | |
| const char *path, | |
size_t length); |
int sd_is_mq( | int fd, |
const char *path); |
int sd_is_special( | int fd, |
const char *path); |
sd_is_fifo() may be called
to check whether the specified file descriptor refers
to a FIFO or pipe. If the path
parameter is not NULL, it is
checked whether the FIFO is bound to the specified
file system path.
sd_is_socket() may be
called to check whether the specified file descriptor
refers to a socket. If the
family parameter is not
AF_UNSPEC, it is checked whether
the socket is of the specified family (AF_UNIX,
AF_INET, ...). If the
type parameter is not 0, it is
checked whether the socket is of the specified type
(SOCK_STREAM,
SOCK_DGRAM, ...). If the
listening parameter is positive,
it is checked whether the socket is in accepting mode,
i.e. listen() has been called for
it. If listening is 0, it is
checked whether the socket is not in this mode. If the
parameter is negative, no such check is made. The
listening parameter should only
be used for stream sockets and should be set to a
negative value otherwise.
sd_is_socket_inet() is
similar to sd_is_socket(), but
optionally checks the IPv4 or IPv6 port number the
socket is bound to, unless port
is zero. For this call family
must be passed as either AF_UNSPEC, AF_INET, or
AF_INET6.
sd_is_socket_unix() is
similar to sd_is_socket() but
optionally checks the AF_UNIX path the socket is bound
to, unless the path parameter
is NULL. For normal file system AF_UNIX sockets,
set the length parameter to 0. For
Linux abstract namespace sockets, set the
length to the size of the
address, including the initial 0 byte, and set the
path to the initial 0 byte of
the socket address.
sd_is_mq() may be called to
check whether the specified file descriptor refers to
a POSIX message queue. If the
path parameter is not
NULL, it is checked whether the
message queue is bound to the specified name.
sd_is_special() may be
called to check whether the specified file descriptor
refers to a special file. If the
path parameter is not
NULL, it is checked whether the file
descriptor is bound to the specified file
name. Special files in this context are character
device nodes and files in /proc
or /sys.
On failure, these calls return a negative errno-style error code. If the file descriptor is of the specified type and bound to the specified address, a positive return value is returned, otherwise zero.
These APIs are implemented as a shared
library, which can be compiled and linked to with the
libsystemd pkg-config(1)
file.
Internally, these function use a combination of
fstat() and
getsockname() to check the file
descriptor type and where it is bound to.