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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | CONFORMING TO | NOTES | SEE ALSO | COLOPHON |
BINDRESVPORT(3) Linux Programmer's Manual BINDRESVPORT(3)
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:
EACCES The calling process was not privileged (on Linux: the calling
process did not have the CAP_NET_BIND_SERVICE capability in
the user namespace governing its network namespace).
EADDRINUSE
All privileged ports are in use.
EAFNOSUPPORT (EPFNOSUPPORT in glibc 2.7 and earlier)
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 │
│ │ │ 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.
Not in POSIX.1. Present on the BSDs, Solaris, and many other
systems.
Unlike some bindresvport() implementations, the glibc implementation
ignores any value that the caller supplies in sin->sin_port.
bind(2), getsockname(2)
This page is part of release 4.12 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/.
2016-10-08 BINDRESVPORT(3)