1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
|
.TH VENTI-SERVER 3
.SH NAME
vtsrvhello, vtlisten, vtgetreq, vtrespond \- Venti server
.SH SYNOPSIS
.PP
.ft L
#include <u.h>
.br
#include <libc.h>
.br
#include <venti.h>
.ta +\w'\fLVtReq* 'u
.PP
.ft L
.nf
typedef struct VtReq
{
VtFcall tx;
VtFcall rx;
...
} VtReq;
.PP
.B
int vtsrvhello(VtConn *z)
.PP
.B
VtSrv* vtlisten(char *addr)
.PP
.B
VtReq* vtgetreq(VtSrv *srv)
.PP
.B
void vtrespond(VtReq *req)
.SH DESCRIPTION
These routines execute the server side of the
.IR venti (7)
protocol.
.PP
.I Vtsrvhello
executes the server side of the initial
.B hello
transaction.
It sets
.IB z -> uid
with the user name claimed by the other side.
Each new connection must be initialized by running
.I vtversion
and then
.IR vtsrvhello .
The framework below takes care of this detail automatically;
.I vtsrvhello
is provided for programs that do not use the functions below.
.PP
.IR Vtlisten ,
.IR vtgetreq ,
and
.I vtrespond
provide a simple framework for writing Venti servers.
.PP
.I Vtlisten
announces at the network address
.IR addr ,
returning a fresh
.B VtSrv
structure representing the service.
.PP
.I Vtgetreq
waits for and returns
the next
.BR read ,
.BR write ,
.BR sync ,
or
.B ping
request from any client connected to
the service
.IR srv .
.B Hello
and
.B goodbye
messages are handled internally and not returned to the client.
The interface does not distinguish between the
different clients that may be connected at any given time.
The request can be found in the
.I tx
field of the returned
.BR VtReq .
.PP
Once a request has been served and a response stored in
.IB r ->rx \fR,
the server should call
.IR vtrespond
to send the response to the client.
.I Vtrespond
frees the structure
.I r
as well as the packets
.IB r ->tx.data
and
.IB r ->rx.data \fR.
.SH EXAMPLE
.B \*9/src/venti/cmd
contains two simple Venti servers
.B ro.c
and
.B devnull.c
written using these routines.
.I Ro
is a read-only Venti proxy (it rejects
.B write
requests).
.I Devnull
is a write-only Venti server: it discards all
blocks written to it and returns error on all reads.
.SH SOURCE
.B \*9/src/libventi
.SH SEE ALSO
.IR venti (1),
.IR venti (3),
.IR venti-conn (3),
.IR venti-packet (3)
|