привязать имя к сокету (bind a name to a socket)
Имя (Name)
bind - bind a name to a socket
Синопсис (Synopsis)
#include <sys/socket.h>
int bind(int sockfd, const struct sockaddr *addr,
socklen_t addrlen);
Описание (Description)
When a socket is created with socket(2), it exists in a name
space (address family) but has no address assigned to it. bind()
assigns the address specified by addr to the socket referred to
by the file descriptor sockfd. addrlen specifies the size, in
bytes, of the address structure pointed to by addr.
Traditionally, this operation is called 'assigning a name to a
socket'.
It is normally necessary to assign a local address using bind()
before a SOCK_STREAM socket may receive connections (see
accept(2)).
The rules used in name binding vary between address families.
Consult the manual entries in Section 7 for detailed information.
For AF_INET, see ip(7); for AF_INET6, see ipv6(7); for AF_UNIX,
see unix(7); for AF_APPLETALK, see ddp(7); for AF_PACKET, see
packet(7); for AF_X25, see x25(7); and for AF_NETLINK, see
netlink(7).
The actual structure passed for the addr argument will depend on
the address family. The sockaddr structure is defined as
something like:
struct sockaddr {
sa_family_t sa_family;
char sa_data[14];
}
The only purpose of this structure is to cast the structure
pointer passed in addr in order to avoid compiler warnings. See
EXAMPLES below.
Возвращаемое значение (Return value)
On success, zero is returned. On error, -1 is returned, and
errno is set to indicate the error.
Ошибки (Error)
EACCES The address is protected, and the user is not the
superuser.
EADDRINUSE
The given address is already in use.
EADDRINUSE
(Internet domain sockets) The port number was specified as
zero in the socket address structure, but, upon attempting
to bind to an ephemeral port, it was determined that all
port numbers in the ephemeral port range are currently in
use. See the discussion of
/proc/sys/net/ipv4/ip_local_port_range ip(7).
EBADF sockfd is not a valid file descriptor.
EINVAL The socket is already bound to an address.
EINVAL addrlen is wrong, or addr is not a valid address for this
socket's domain.
ENOTSOCK
The file descriptor sockfd does not refer to a socket.
The following errors are specific to UNIX domain (AF_UNIX)
sockets:
EACCES Search permission is denied on a component of the path
prefix. (See also path_resolution(7).)
EADDRNOTAVAIL
A nonexistent interface was requested or the requested
address was not local.
EFAULT addr points outside the user's accessible address space.
ELOOP Too many symbolic links were encountered in resolving
addr.
ENAMETOOLONG
addr is too long.
ENOENT A component in the directory prefix of the socket pathname
does not exist.
ENOMEM Insufficient kernel memory was available.
ENOTDIR
A component of the path prefix is not a directory.
EROFS The socket inode would reside on a read-only filesystem.
Стандарты (Conforming to)
POSIX.1-2001, POSIX.1-2008, SVr4, 4.4BSD (bind() first appeared
in 4.2BSD).
Примечание (Note)
For background on the socklen_t type, see accept(2).
Ошибки (баги) (Bugs)
The transparent proxy options are not described.
Примеры (Examples)
An example of the use of bind() with Internet domain sockets can
be found in getaddrinfo(3).
The following example shows how to bind a stream socket in the
UNIX (AF_UNIX) domain, and accept connections:
#include <sys/socket.h>
#include <sys/un.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#define MY_SOCK_PATH "/somepath"
#define LISTEN_BACKLOG 50
#define handle_error(msg) \
do { perror(msg); exit(EXIT_FAILURE); } while (0)
int
main(int argc, char *argv[])
{
int sfd, cfd;
struct sockaddr_un my_addr, peer_addr;
socklen_t peer_addr_size;
sfd = socket(AF_UNIX, SOCK_STREAM, 0);
if (sfd == -1)
handle_error("socket");
memset(&my_addr, 0, sizeof(my_addr));
my_addr.sun_family = AF_UNIX;
strncpy(my_addr.sun_path, MY_SOCK_PATH,
sizeof(my_addr.sun_path) - 1);
if (bind(sfd, (struct sockaddr *) &my_addr,
sizeof(my_addr)) == -1)
handle_error("bind");
if (listen(sfd, LISTEN_BACKLOG) == -1)
handle_error("listen");
/* Now we can accept incoming connections one
at a time using accept(2). */
peer_addr_size = sizeof(peer_addr);
cfd = accept(sfd, (struct sockaddr *) &peer_addr,
&peer_addr_size);
if (cfd == -1)
handle_error("accept");
/* Code to deal with incoming connection(s)... */
/* When no longer required, the socket pathname, MY_SOCK_PATH
should be deleted using unlink(2) or remove(3). */
}
Смотри также (See also)
accept(2), connect(2), getsockname(2), listen(2), socket(2),
getaddrinfo(3), getifaddrs(3), ip(7), ipv6(7),
path_resolution(7), socket(7), unix(7)
