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


#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)

int          vtreconn(VtConn *z, int infd, int outfd)

VtConn*      vtdial(char *addr)

int          vtredial(VtConn *z, char *addr)

int          vtversion(VtConn *z)

int          vtsend(VtConn *z, Packet *p)

Packet*      vtrecv(VtConn *z)

void         vtrecvproc(void *z)

void         vtsendproc(void *z)

void         vtdebug(VtConn *z, char *fmt, ...)

void         vthangup(VtConn *z)

void         vtfreeconn(VtConn *z)

extern int chattyventi;/* default 0 */

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.


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

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