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NetBSD 6.1.5 - man page for bind (netbsd section 2)

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BIND(2) 			     BSD System Calls Manual				  BIND(2)

NAME
     bind -- bind a name to a socket

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <sys/socket.h>

     int
     bind(int s, const struct sockaddr *name, socklen_t namelen);

DESCRIPTION
     bind() assigns a name to an unnamed socket.  When a socket is created with socket(2) it
     exists in a name space (address family) but has no name assigned.	bind() requests that name
     be assigned to the socket.  namelen indicates the amount of space pointed to by name, in
     bytes.

NOTES
     Binding a name in the UNIX domain creates a socket in the file system that must be deleted
     by the caller when it is no longer needed (using unlink(2)).

     The rules used in name binding vary between communication domains.  Consult the manual
     entries in section 4 for detailed information.

RETURN VALUES
     If the bind is successful, a 0 value is returned.	A return value of -1 indicates an error,
     which is further specified in the global errno.

ERRORS
     The bind() call will fail if:

     [EBADF]		s is not a valid descriptor.

     [ENOTSOCK] 	s is not a socket.

     [EADDRNOTAVAIL]	The specified address is not available from the local machine.

     [EADDRINUSE]	The specified address is already in use.

     [EINVAL]		The socket is already bound to an address.

     [EINVAL]		The family of the socket and that requested in name->sa_family are not
			equivalent.

     [EACCES]		The requested address is protected, and the current user has inadequate
			permission to access it.

     [EFAULT]		The name parameter is not in a valid part of the user address space.

     The following errors are specific to binding names in the UNIX domain.

     [ENOTDIR]		A component of the path prefix is not a directory.

     [ENAMETOOLONG]	A component of a pathname exceeded {NAME_MAX} characters, or an entire
			path name exceeded {PATH_MAX} characters.

     [ENOENT]		A prefix component of the path name does not exist.

     [ELOOP]		Too many symbolic links were encountered in translating the pathname.

     [EIO]		An I/O error occurred while making the directory entry or allocating the
			inode.

     [EROFS]		The name would reside on a read-only file system.

     [EISDIR]		An empty pathname was specified.

SEE ALSO
     connect(2), getsockname(2), listen(2), socket(2)

HISTORY
     The bind() function call appeared in 4.2BSD.

SECURITY CONSIDERATIONS
     bind() was changed in NetBSD 1.4 to prevent the binding of a socket to the same port as an
     existing socket when all of the following is true:
	   o   either of the existing or new addresses is INADDR_ANY,
	   o   the uid of the new socket is not root, and the uids of the creators of the sockets
	       are different,
	   o   the address is not a multicast address, and
	   o   both sockets are not bound to INADDR_ANY with SO_REUSEPORT set.

     This prevents an attack where a user could bind to a port with the host's IP address (after
     setting SO_REUSEADDR) and 'steal' packets destined for a server that bound to the same port
     with INADDR_ANY.

     bind() was changed in NetBSD 4.0 to honor the user's umask when binding sockets in the local
     domain.  This was done to match the behavior of other operating systems, including FreeBSD,
     OpenBSD, and Linux, and to improve compatibility with some third-party software.  Please
     note that this behavior is not portable.  If you must bind a local socket in a portable and
     secure way, you need to make a directory with tight permissions and then create the socket
     inside it.

BSD					 August 30, 2005				      BSD
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