NAME

VtConn, vtconn, vtdial, vtfreeconn, vtsend, vtrecv, vtversion, vtdebug, vthangup − Venti network connections

SYNOPSIS

#include <u.h>
#include <libc.h>
#include <venti.h>

typedef struct VtConn {
int  debug;
char ∗version;
char ∗uid;
char ∗sid;
char addr[256];
...
} VtConn;

VtConn∗vtconn(int infd, int outfd)

VtConn∗vtdial(char ∗addr)

intvtversion(VtConn ∗z)

intvtsend(VtConn ∗z, Packet ∗p)

Packet∗vtrecv(VtConn ∗z)

voidvtrecvproc(void ∗z)

voidvtsendproc(void ∗z)

voidvtdebug(VtConn ∗z, char ∗fmt, ...)

voidvthangup(VtConn ∗z)

voidvtfreeconn(VtConn ∗z)

extern intchattyventi; /∗ default 0 ∗/

DESCRIPTION

A ­VtConn structure represents a connection to a Venti server (when used by a client) or to a client (when used by a server).  It contains the following user-visible fields: debug, a flag enabling debugging prints; version, the protocol version in use; uid, the (unverified) name of the client; sid, the (unverified) name of the server; and addr, the network address of the remote side. 

­Vtconn initializes a new connection structure using file descriptors ­infd and ­outfd (which may be the same) for reading and writing.  ­Vtdial dials the given network address (see dial(2)) and returns a corresponding connection. If ­addr is nil, the environment variable ­venti will be used if set; if not, the address ­tcp!$venti!venti will be used.  It returns ­nil if the connection cannot be established. 

­Vtversion exchanges version information with the remote side as described in venti(6). The negotiated version is stored in z->version. 

­Vtsend writes a packet (see venti-packet(2)) on the connection z. The packet ­p should be a formatted Venti message as might be returned by vtfcallpack; ­vtsend will add the two-byte length field (see venti(6)) at the begnning. ­Vtsend frees p, even on error.

­Vtrecv reads a packet from the connection z. Analogous to vtsend, the data read from the connection must start with a two-byte length, but the returned packet will omit them.

By default, ­vtsend and ­vtrecv block until the packet can be written or read from the network.  In a threaded program (see thread(2)), this may not be desirable. If the caller arranges for vtsendproc and vtrecvproc to run in their own procs (typically by calling proccreate), then ­vtsend and ­vtrecv will yield the proc in which they are run to other threads when waiting on the network.  The ­void∗ argument to ­vtsendproc and ­vtrecvproc must be the connection structure z.

­Vtdebug prints the formatted message to standard error when z->debug is set.  Otherwise it is a no-op. 

­Vthangup hangs up a connection.  It closes the associated file descriptors and shuts down send and receive procs if they have been started.  Future calls to vtrecv or vtsend will return errors.  Additional calls to ­vthangup will have no effect. 

­Vtfreeconn frees the connection structure, hanging it up first if necessary. 

If the global variable ­chattyventi is set, the library prints all Venti RPCs to standard error as they are sent or received. 

SOURCE

­/sys/src/libventi

SEE ALSO

venti(1), venti(2), venti-client(2), venti-packet(2), venti-server(2), venti(6)

DIAGNOSTICS

Routines that return pointers return nil on error.  Routines returning integers return 0 on success, −1 on error.  All routines set ­errstr on error. 

Plan 9  —  August 02, 2013