bindresvport — bind a socket to a privileged IP port
#include <sys/types.h> #include <netinet/in.h>
int
bindresvport( |
int sockfd, |
struct sockaddr_in *sin); |
bindresvport() is used to
bind the socket referred to by the file descriptor sockfd to a privileged
anonymous IP port, that is, a port number arbitrarily
selected from the range 512 to 1023.
If the bind(2) performed by
bindresvport() is successful,
and sin is not NULL,
then sin−>sin_port
returns the port number actually allocated.
sin can be NULL,
in which case sin−>sin_family is
implicitly taken to be AF_INET.
However, in this case, bindresvport() has no way to return the
port number actually allocated. (This information can later
be obtained using getsockname(2).)
bindresvport() returns 0 on
success; otherwise −1 is returned and errno set to indicate the cause of the
error.
bindresvport() can fail for
any of the same reasons as bind(2). In addition, the
following errors may occur:
The caller did not have superuser privilege (to be
precise: the CAP_NET_BIND_SERVICE capability is
required).
All privileged ports are in use.
sin is not
NULL and sin->sin_family is
not AF_INET.
For an explanation of the terms used in this section, see attributes(7).
| Interface | Attribute | Value |
bindresvport() |
Thread safety |
glibc >= 2.17: MT-Safe .\" commit f6da27e53695ad1cc0e2a9490358decbbfdff5e5 glibc < 2.17: MT-Unsafe |
The bindresvport() function
uses a static variable that was not protected by a lock
before glibc 2.17, rendering the function MT-Unsafe.
Unlike some bindresvport()
implementations, the glibc implementation ignores any value
that the caller supplies in sin−>sin_port.
This page is part of release 4.07 of the Linux man-pages project. A
description of the project, information about reporting bugs,
and the latest version of this page, can be found at
https://www.kernel.org/doc/man−pages/.
|
Copyright (C) 2007, Michael Kerrisk <mtk.manpagesgmail.com> and Copyright (C) 2008, Linux Foundation, written by Michael Kerrisk <mtk.manpagesgmail.com> %%%LICENSE_START(VERBATIM) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. %%%LICENSE_END 2007-05-31, mtk: Rewrite and substantial additional text. 2008-12-03, mtk: Rewrote some pieces and fixed some errors |