проверить тип дескриптора файла (check the type of a file descriptor)
Имя (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
Синопсис (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);
Описание (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/.
Возвращаемое значение (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.
Примечание (Note)
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.
Смотри также (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).
