Ubuntu Manpage: sd_is_fifo, sd_is_socket, sd_is_socket_inet, sd_is_socket_unix, sd_is_socket

Provided by: libsystemd-dev_256.5-2ubuntu4_amd64

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

       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.

HISTORY