1SD_IS_FIFO(3) sd_is_fifo SD_IS_FIFO(3)
2
6 sd_is_fifo, sd_is_socket, sd_is_socket_inet, sd_is_socket_unix,
7 sd_is_socket_sockaddr, sd_is_mq, sd_is_special - Check the type of a
8 file descriptor
9
11 #include <systemd/sd-daemon.h>
12 int sd_is_fifo(int fd, const char *path);
14 int sd_is_socket(int fd, int family, int type, int listening);
16 int sd_is_socket_inet(int fd, int family, int type, int listening,
18 uint16_t port);
19 int sd_is_socket_sockaddr(int fd, int type,
21 const struct sockaddr *addr,
22 unsigned addr_len, int listening);
23 int sd_is_socket_unix(int fd, int type, int listening,
25 const char *path, size_t length);
26 int sd_is_mq(int fd, const char *path);
28 int sd_is_special(int fd, const char *path);
30
32 sd_is_fifo() may be called to check whether the specified file
33 descriptor refers to a FIFO or pipe. If the path parameter is not NULL,
34 it is checked whether the FIFO is bound to the specified file system
35 path.
36 sd_is_socket() may be called to check whether the specified file
38 descriptor refers to a socket. If the family parameter is not
39 AF_UNSPEC, it is checked whether the socket is of the specified family
40 (AF_UNIX, AF_INET, ...). If the type parameter is not 0, it is checked
41 whether the socket is of the specified type (SOCK_STREAM, SOCK_DGRAM,
42 ...). If the listening parameter is positive, it is checked whether the
43 socket is in accepting mode, i.e. listen() has been called for it. If
44 listening is 0, it is checked whether the socket is not in this mode.
45 If the parameter is negative, no such check is made. The listening
46 parameter should only be used for stream sockets and should be set to a
47 negative value otherwise.
48 sd_is_socket_inet() is similar to sd_is_socket(), but optionally checks
50 the IPv4 or IPv6 port number the socket is bound to, unless port is
51 zero. For this call family must be passed as either AF_UNSPEC, AF_INET,
52 or AF_INET6.
53 sd_is_socket_sockaddr() is similar to sd_is_socket_inet(), but checks
55 if the socket is bound to the address specified by addr. The family
56 specified by addr must be either AF_INET or AF_INET6 and addr_len must
57 be large enough for that family. If addr specifies a non-zero port, it
58 is also checked if the socket is bound to this port. In addition, for
59 IPv6, if addr specifies non-zero sin6_flowinfo or sin6_scope_id, it is
60 checked if the socket has the same values.
61 sd_is_socket_unix() is similar to sd_is_socket() but optionally checks
63 the AF_UNIX path the socket is bound to, unless the path parameter is
64 NULL. For normal file system AF_UNIX sockets, set the length parameter
65 to 0. For Linux abstract namespace sockets, set the length to the size
66 of the address, including the initial 0 byte, and set the path to the
67 initial 0 byte of the socket address.
68 sd_is_mq() may be called to check whether the specified file descriptor
70 refers to a POSIX message queue. If the path parameter is not NULL, it
71 is checked whether the message queue is bound to the specified name.
72 sd_is_special() may be called to check whether the specified file
74 descriptor refers to a special file. If the path parameter is not NULL,
75 it is checked whether the file descriptor is bound to the specified
76 filename. Special files in this context are character device nodes and
77 files in /proc or /sys.
78
80 On failure, these calls return a negative errno-style error code. If
81 the file descriptor is of the specified type and bound to the specified
82 address, a positive return value is returned, otherwise zero.
83
85 These APIs are implemented as a shared library, which can be compiled
86 and linked to with the libsystemd pkg-config(1) file.
87 Internally, these function use a combination of fstat() and
89 getsockname() to check the file descriptor type and where it is bound
90 to.
91
93 systemd(1), sd-daemon(3), sd_listen_fds(3), systemd.service(5),
94 systemd.socket(5), ip(7), ipv6(7), unix(7), fifo(7), mq_overview(7),
95 socket(7).
96systemd 239 SD_IS_FIFO(3)