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rresvport_af(3) [osf1 man page]

rresvport_af(3) 					     Library Functions Manual						   rresvport_af(3)

rresvport_af - Retrieves a socket with a privileged address LIBRARY
Standard C Library (libc.a) SYNOPSIS
#include <unistd.h> int rresvport_af ( int *port, int family ); PARAMETERS
Specifies the port to use for the connection. Specifies the address family for the socket to be created. Valid values are AF_INET (IPv4) and AF_INET6 (IPv6). DESCRIPTION
The rresvport_af() function obtains a socket with a privileged address bound to the socket. A privileged Internet port is one that falls in the range of 0 to 1023. Only processes with an effective user ID of root can use the rresvport_af() function. An authentication scheme based on remote port num- bers is used to verify permissions. If the connection succeeds, a socket in the Internet domain of type SOCK_STREAM for the specified address family is returned to the calling process. RETURN VALUES
Upon successful completion, the rresvport_af() function returns a valid, bound socket descriptor. Otherwise, a value of -1 is returned and errno is set to indicate the error. ERRORS
If the rresvport_af() function fails, errno may be set to one of the following values: All network ports are in use. The addresses in the specified address family cannot be used with this socket. Two hundred (200) file descriptors are currently open. The system file table is full. Insufficient buffers are available in the system to complete the function. FILES
Contains the service names. RELATED INFORMATION
Functions: rcmd(3), ruserok(3) delim off rresvport_af(3)

Check Out this Related Man Page

rcmd(3SOCKET)						     Sockets Library Functions						     rcmd(3SOCKET)

rcmd, rcmd_af, rresvport, rresvport_af, ruserok - routines for returning a stream to a remote command SYNOPSIS
cc [ flag ... ] file... -lsocket -lnsl [ library... ] #include <netdb.h> #include <unistd.h> int rcmd(char **ahost, unsigned short inport, const char *luser, const char *ruser, const char *cmd, int *fd2p); int rcmd_af(char **ahost, unsigned short inport, const char *luser, const char *ruser, const char *cmd, int *fd2p, int af); int rresvport(int *port); int rresvport_af(int *port, int af); int ruserok(const char *rhost, int suser, const char *ruser, const char *luser); DESCRIPTION
The rcmd() function is used by the superuser to execute a command on a remote machine with an authentication scheme based on reserved port numbers. An AF_INET socket is returned with rcmd(). The rcmd_af() function supports AF_INET, AF_INET6 or AF_UNSPEC for the address family. An application can choose which type of socket is returned by passing AF_INET or AF_INET6 as the address family. The use of AF_UNSPEC means that the caller will accept any address family. Choosing AF_UNSPEC provides a socket that best suits the connectivity to the remote host. The rresvport() function returns a descriptor to a socket with an address in the privileged port space. The rresvport_af() function is the equivalent to rresvport(), except that you can choose AF_INET or AF_INET6 as the socket address family to be returned by rresvport_af(). AF_UNSPEC does not apply to the rresvport() function. The ruserok() function is a routine used by servers to authenticate clients that request as service with rcmd. All of these functions are present in the same file and are used by the in.rshd(1M) server among others. The rcmd() and rcmd_af() functions look up the host *ahost using getaddrinfo(3SOCKET) and return -1 if the host does not exist. Otherwise, *ahost is set to the standard name of the host and a connection is established to a server residing at the Internet port inport. If the connection succeeds, a socket in the Internet domain of type SOCK_STREAM is returned to the caller. The socket is given to the remote command as standard input (file descriptor 0) and standard output (file descriptor 1). If fd2p is non-zero, an auxiliary channel to a control process is set up and a descriptor for it is placed in *fd2p. The control process returns diagnostic output file (descriptor 2) from the command on the auxiliary channel. The control process also accepts bytes on this channel as signal numbers to be forwarded to the process group of the command. If fd2p is 0, the standard error (file descriptor 2) of the remote command is made the same as its standard output. No provision is made for sending arbitrary signals to the remote process, other than possibly sending out-of-band data. The protocol is described in detail in in.rshd(1M). The rresvport() and rresvport_af() functions are used to obtain a socket bound to a privileged port number. The socket is suitable for use by rcmd() and rresvport_af() and several other routines. Privileged Internet ports are those in the range 1 to 1023. Only the superuser is allowed to bind a socket to a privileged port number. The application must pass in port, which must be in the range 512 to 1023. The system first tries to bind to that port number. If it fails, the system then tries to bind to another unused privileged port, if one is avail- able. The ruserok() function takes a remote host name returned by the gethostbyaddr() function with two user names and a flag to indicate whether the local user's name is that of the superuser. See gethostbyname(3NSL). The ruserok() function then checks the files /etc/hosts.equiv and possibly .rhosts in the local user's home directory to see if the request for service is allowed. A 0 value is returned if the machine name is listed in the /etc/hosts.equiv file, or if the host and remote user name are found in the .rhosts file. Otherwise, the ruserok() func- tion returns -1. If the superuser flag is 1, the /etc/hosts.equiv is not checked. The error code EAGAIN is overloaded to mean "All network ports in use." RETURN VALUES
The rcmd() and rcmd_af() functions return a valid socket descriptor upon success. The functions returns -1 upon error and print a diagnos- tic message to standard error. The rresvport() and rresvport_af() functions return a valid, bound socket descriptor upon success. The functions return -1 upon error with the global value errno set according to the reason for failure. FILES
/etc/hosts.equiv system trusted hosts and users ~/.rhosts user's trusted hosts and users ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |MT-Level |Unsafe | +-----------------------------+-----------------------------+ This interface is Unsafe in multithreaded applications. Unsafe interfaces should be called only from the main thread. SEE ALSO
rlogin(1), rsh(1), in.rexecd(1M), in.rshd(1M), intro(2), getaddrinfo(3SOCKET), gethostbyname(3NSL), rexec(3SOCKET), attributes(5) SunOS 5.10 10 Feb 2004 rcmd(3SOCKET)
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