sd_is_fifo, sd_is_socket, sd_is_socket_inet, sd_is_socket_unix, sd_is_socket_sockaddr, 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_sockaddr( | int fd, |
| int type, | |
| const struct sockaddr *addr, | |
| unsigned addr_len, | |
int listening); |
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_sockaddr() is similar to
sd_is_socket_inet(), but checks if the socket is bound to the
address specified by addr. The
family specified by addr must be
either AF_INET or AF_INET6 and
addr_len must be large enough for that family. If
addr specifies a non-zero port, it is also checked if the
socket is bound to this port. In addition, for IPv6, if addr
specifies non-zero sin6_flowinfo or
sin6_scope_id, it is checked if the socket has the same
values.
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 filename. 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.
Functions described here are available as a shared
library, which can be compiled against and linked to with the
libsystemd pkg-config(1)
file.
Internally, these functions use a combination of fstat(2) and getsockname(2) to check the file descriptor type and where it is bound to.