sd_is_socket

SD_IS_FIFO(3)                      sd_is_fifo                      SD_IS_FIFO(3)



NAME
       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

SYNOPSIS
       #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);

DESCRIPTION
       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.

RETURN VALUE
       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.

NOTES
       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.

SEE ALSO
       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).




systemd 246                                                        SD_IS_FIFO(3)