minix/lib/libc/sys/bind.2
Ben Gras 2fe8fb192f Full switch to clang/ELF. Drop ack. Simplify.
There is important information about booting non-ack images in
docs/UPDATING. ack/aout-format images can't be built any more, and
booting clang/ELF-format ones is a little different. Updating to the
new boot monitor is recommended.

Changes in this commit:

	. drop boot monitor -> allowing dropping ack support
	. facility to copy ELF boot files to /boot so that old boot monitor
	  can still boot fairly easily, see UPDATING
	. no more ack-format libraries -> single-case libraries
	. some cleanup of OBJECT_FMT, COMPILER_TYPE, etc cases
	. drop several ack toolchain commands, but not all support
	  commands (e.g. aal is gone but acksize is not yet).
	. a few libc files moved to netbsd libc dir
	. new /bin/date as minix date used code in libc/
	. test compile fix
	. harmonize includes
	. /usr/lib is no longer special: without ack, /usr/lib plays no
	  kind of special bootstrapping role any more and bootstrapping
	  is done exclusively through packages, so releases depend even
	  less on the state of the machine making them now.
	. rename nbsd_lib* to lib*
	. reduce mtree
2012-02-14 14:52:02 +01:00

185 lines
5.3 KiB
Groff

.\" $NetBSD: bind.2,v 1.27 2010/05/31 12:16:20 njoly Exp $
.\"
.\" Copyright (c) 1983, 1993
.\" The Regents of the University of California. All rights reserved.
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.\" notice, this list of conditions and the following disclaimer in the
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.\" may be used to endorse or promote products derived from this software
.\" without specific prior written permission.
.\"
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\"
.\" @(#)bind.2 8.1 (Berkeley) 6/4/93
.\"
.Dd August 30, 2005
.Dt BIND 2
.Os
.Sh NAME
.Nm bind
.Nd bind a name to a socket
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/socket.h
.Ft int
.Fn bind "int s" "const struct sockaddr *name" "socklen_t namelen"
.Sh DESCRIPTION
.Fn bind
assigns a name to an unnamed socket.
When a socket is created
with
.Xr socket 2
it exists in a name space (address family)
but has no name assigned.
.Fn bind
requests that
.Fa name
be assigned to the socket.
.Fa namelen
indicates the amount of space pointed to by
.Fa name ,
in bytes.
.Sh NOTES
Binding a name in the
.Ux
domain creates a socket in the file
system that must be deleted by the caller when it is no longer
needed (using
.Xr unlink 2 ) .
.Pp
The rules used in name binding vary between communication domains.
Consult the manual entries in section 4 for detailed information.
.Sh 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
.Va errno .
.Sh ERRORS
The
.Fn bind
call will fail if:
.Bl -tag -width Er
.It Bq Er EBADF
.Fa s
is not a valid descriptor.
.It Bq Er ENOTSOCK
.Fa s
is not a socket.
.It Bq Er EADDRNOTAVAIL
The specified address is not available from the local machine.
.It Bq Er EADDRINUSE
The specified address is already in use.
.It Bq Er EINVAL
The socket is already bound to an address.
.It Bq Er EINVAL
The family of the socket and that requested in
.Fa name-\*[Gt]sa_family
are not equivalent.
.It Bq Er EACCES
The requested address is protected, and the current user
has inadequate permission to access it.
.It Bq Er EFAULT
The
.Fa name
parameter is not in a valid part of the user
address space.
.El
.Pp
The following errors are specific to binding names in the
.Ux
domain.
.Bl -tag -width Er
.It Bq Er ENOTDIR
A component of the path prefix is not a directory.
.It Bq Er ENAMETOOLONG
A component of a pathname exceeded
.Brq Dv NAME_MAX
characters, or an entire path name exceeded
.Brq Dv PATH_MAX
characters.
.It Bq Er ENOENT
A prefix component of the path name does not exist.
.It Bq Er ELOOP
Too many symbolic links were encountered in translating the pathname.
.It Bq Er EIO
An I/O error occurred while making the directory entry or allocating the inode.
.It Bq Er EROFS
The name would reside on a read-only file system.
.It Bq Er EISDIR
An empty pathname was specified.
.El
.Sh SEE ALSO
.Xr connect 2 ,
.Xr getsockname 2 ,
.Xr listen 2 ,
.Xr socket 2
.Sh HISTORY
The
.Fn bind
function call appeared in
.Bx 4.2 .
.Sh SECURITY CONSIDERATIONS
.Fn bind
was changed in
.Nx 1.4
to prevent the binding of a socket to the same port as an existing
socket when all of the following is true:
.Bl -bullet -compact -offset indent
.It
either of the existing or new addresses is
.Li INADDR_ANY ,
.It
the uid of the new socket is not root, and
the uids of the creators of the sockets are different,
.It
the address is not a multicast address, and
.It
both sockets are not bound to
.Li INADDR_ANY
with
.Li SO_REUSEPORT
set.
.El
.Pp
This prevents an attack where a user could bind to a port with
the host's IP address (after setting
.Li SO_REUSEADDR )
and
.Sq steal
packets destined for a server that bound to the
same port with
.Li INADDR_ANY .
.Pp
.Fn bind
was changed in
.Nx 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
.Fx ,
.Ox ,
and
Linux, and to improve compatibility with some third-party software.
Please note that this behavior
.Em 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.