sd_is_fifo - Man Page

#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​.

sd_is_special() was added in version 209​.

sd_is_socket_sockaddr() was added in version 233​.

systemd(1), sd-daemon(3), sd_listen_fds(3), systemd.service(5), systemd.socket(5), ip(7), ipv6(7), unix(7), fifo(7), mq_overview(7), socket(7)​.

sd-daemon(3), sd_listen_fds(3), systemd.directives(7), systemd.index(7).

The man pages sd_is_mq(3), sd_is_socket(3), sd_is_socket_inet(3), sd_is_socket_sockaddr(3), sd_is_socket_unix(3) and sd_is_special(3) are aliases of sd_is_fifo(3).