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/*++
/* NAME
/* attr_clnt 3
/* SUMMARY
/* attribute query-reply client
/* SYNOPSIS
/* #include <attr_clnt.h>
/*
/* typedef int (*ATTR_CLNT_PRINT_FN) (VSTREAM *, int, va_list);
/* typedef int (*ATTR_CLNT_SCAN_FN) (VSTREAM *, int, va_list);
/*
/* ATTR_CLNT *attr_clnt_create(server, timeout, max_idle, max_ttl)
/* const char *server;
/* int timeout;
/* int max_idle;
/* int max_ttl;
/*
/* int attr_clnt_request(client,
/* send_flags, send_type, send_name, ..., ATTR_TYPE_END,
/* recv_flags, recv_type, recv_name, ..., ATTR_TYPE_END)
/* ATTR_CLNT *client;
/* int send_flags;
/* int send_type;
/* const char *send_name;
/* int recv_flags;
/* int recv_type;
/* const char *recv_name;
/*
/* void attr_clnt_free(client)
/* ATTR_CLNT *client;
/*
/* void attr_clnt_control(client, name, value, ... ATTR_CLNT_CTL_END)
/* ATTR_CLNT *client;
/* int name;
/* DESCRIPTION
/* This module implements a client for a simple attribute-based
/* protocol. The default protocol is described in attr_scan_plain(3).
/*
/* attr_clnt_create() creates a client handle. See auto_clnt(3) for
/* a description of the arguments.
/*
/* attr_clnt_request() sends the specified request attributes and
/* receives a reply. The reply argument specifies a name-value table.
/* The other arguments are as described in attr_print_plain(3). The
/* result is the number of attributes received or -1 in case of trouble.
/*
/* attr_clnt_free() destroys a client handle and closes its connection.
/*
/* attr_clnt_control() allows the user to fine tune the behavior of
/* the specified client. The arguments are a list of (name, value)
/* terminated with ATTR_CLNT_CTL_END.
/* The following lists the names and the types of the corresponding
/* value arguments.
/* .IP "ATTR_CLNT_CTL_PROTO(ATTR_CLNT_PRINT_FN, ATTR_CLNT_SCAN_FN)"
/* Specifies alternatives for the attr_plain_print() and
/* attr_plain_scan() functions.
/* .IP "ATTR_CLNT_CTL_REQ_LIMIT(int)"
/* The maximal number of requests per connection (default: 0,
/* i.e. no limit). To enable the limit, specify a value greater
/* than zero.
/* .IP "ATTR_CLNT_CTL_TRY_LIMIT(int)"
/* The maximal number of attempts to send a request before
/* giving up (default: 2). To disable the limit, specify a
/* value equal to zero.
/* .IP "ATTR_CLNT_CTL_TRY_DELAY(int)"
/* The time in seconds between attempts to send a request
/* (default: 1). Specify a value greater than zero.
/* DIAGNOSTICS
/* Warnings: communication failure.
/* SEE ALSO
/* auto_clnt(3), client endpoint management
/* attr_scan_plain(3), attribute protocol
/* attr_print_plain(3), attribute protocol
/* LICENSE
/* .ad
/* .fi
/* The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/* Wietse Venema
/* IBM T.J. Watson Research
/* P.O. Box 704
/* Yorktown Heights, NY 10598, USA
/*--*/
/* System library. */
#include <sys_defs.h>
#include <unistd.h>
#include <errno.h>
/* Utility library. */
#include <msg.h>
#include <mymalloc.h>
#include <vstream.h>
#include <htable.h>
#include <attr.h>
#include <iostuff.h>
#include <compat_va_copy.h>
#include <auto_clnt.h>
#include <attr_clnt.h>
/* Application-specific. */
struct ATTR_CLNT {
AUTO_CLNT *auto_clnt;
/* Remaining properties are set with attr_clnt_control(). */
ATTR_CLNT_PRINT_FN print;
ATTR_CLNT_SCAN_FN scan;
int req_limit;
int req_count;
int try_limit;
int try_delay;
};
#define ATTR_CLNT_DEF_REQ_LIMIT (0) /* default per-session request limit */
#define ATTR_CLNT_DEF_TRY_LIMIT (2) /* default request (re)try limit */
#define ATTR_CLNT_DEF_TRY_DELAY (1) /* default request (re)try delay */
/* attr_clnt_free - destroy attribute client */
void attr_clnt_free(ATTR_CLNT *client)
{
auto_clnt_free(client->auto_clnt);
myfree((void *) client);
}
/* attr_clnt_create - create attribute client */
ATTR_CLNT *attr_clnt_create(const char *service, int timeout,
int max_idle, int max_ttl)
{
ATTR_CLNT *client;
client = (ATTR_CLNT *) mymalloc(sizeof(*client));
client->auto_clnt = auto_clnt_create(service, timeout, max_idle, max_ttl);
client->scan = attr_vscan_plain;
client->print = attr_vprint_plain;
client->req_limit = ATTR_CLNT_DEF_REQ_LIMIT;
client->req_count = 0;
client->try_limit = ATTR_CLNT_DEF_TRY_LIMIT;
client->try_delay = ATTR_CLNT_DEF_TRY_DELAY;
return (client);
}
/* attr_clnt_request - send query, receive reply */
int attr_clnt_request(ATTR_CLNT *client, int send_flags,...)
{
const char *myname = "attr_clnt_request";
VSTREAM *stream;
int count = 0;
va_list saved_ap;
va_list ap;
int type;
int recv_flags;
int err;
int ret;
/*
* XXX If the stream is readable before we send anything, then assume the
* remote end disconnected.
*
* XXX For some reason we can't simply call the scan routine after the print
* routine, that messes up the argument list.
*/
#define SKIP_ARG(ap, type) { \
(void) va_arg(ap, char *); \
(void) va_arg(ap, type); \
}
#define SKIP_ARG2(ap, t1, t2) { \
SKIP_ARG(ap, t1); \
(void) va_arg(ap, t2); \
}
/* Finalize argument lists before returning. */
va_start(saved_ap, send_flags);
for (;;) {
errno = 0;
if ((stream = auto_clnt_access(client->auto_clnt)) != 0
&& readable(vstream_fileno(stream)) == 0) {
errno = 0;
VA_COPY(ap, saved_ap);
err = (client->print(stream, send_flags, ap) != 0
|| vstream_fflush(stream) != 0);
va_end(ap);
if (err == 0) {
VA_COPY(ap, saved_ap);
while ((type = va_arg(ap, int)) != ATTR_TYPE_END) {
switch (type) {
case ATTR_TYPE_STR:
SKIP_ARG(ap, char *);
break;
case ATTR_TYPE_DATA:
SKIP_ARG2(ap, ssize_t, char *);
break;
case ATTR_TYPE_INT:
SKIP_ARG(ap, int);
break;
case ATTR_TYPE_LONG:
SKIP_ARG(ap, long);
break;
case ATTR_TYPE_HASH:
(void) va_arg(ap, HTABLE *);
break;
default:
msg_panic("%s: unexpected attribute type %d",
myname, type);
}
}
recv_flags = va_arg(ap, int);
ret = client->scan(stream, recv_flags, ap);
va_end(ap);
/* Finalize argument lists before returning. */
if (ret > 0) {
if (client->req_limit > 0
&& (client->req_count += 1) >= client->req_limit) {
auto_clnt_recover(client->auto_clnt);
client->req_count = 0;
}
break;
}
}
}
if ((++count >= client->try_limit && client->try_limit > 0)
|| msg_verbose
|| (errno && errno != EPIPE && errno != ENOENT && errno != ECONNRESET))
msg_warn("problem talking to server %s: %m",
auto_clnt_name(client->auto_clnt));
/* Finalize argument lists before returning. */
if (count >= client->try_limit && client->try_limit > 0) {
ret = -1;
break;
}
sleep(client->try_delay);
auto_clnt_recover(client->auto_clnt);
client->req_count = 0;
}
/* Finalize argument lists before returning. */
va_end(saved_ap);
return (ret);
}
/* attr_clnt_control - fine control */
void attr_clnt_control(ATTR_CLNT *client, int name,...)
{
const char *myname = "attr_clnt_control";
va_list ap;
for (va_start(ap, name); name != ATTR_CLNT_CTL_END; name = va_arg(ap, int)) {
switch (name) {
case ATTR_CLNT_CTL_PROTO:
client->print = va_arg(ap, ATTR_CLNT_PRINT_FN);
client->scan = va_arg(ap, ATTR_CLNT_SCAN_FN);
break;
case ATTR_CLNT_CTL_REQ_LIMIT:
client->req_limit = va_arg(ap, int);
if (client->req_limit < 0)
msg_panic("%s: bad request limit: %d",
myname, client->req_limit);
if (msg_verbose)
msg_info("%s: new request limit %d",
myname, client->req_limit);
break;
case ATTR_CLNT_CTL_TRY_LIMIT:
client->try_limit = va_arg(ap, int);
if (client->try_limit < 0)
msg_panic("%s: bad retry limit: %d", myname, client->try_limit);
if (msg_verbose)
msg_info("%s: new retry limit %d", myname, client->try_limit);
break;
case ATTR_CLNT_CTL_TRY_DELAY:
client->try_delay = va_arg(ap, int);
if (client->try_delay <= 0)
msg_panic("%s: bad retry delay: %d", myname, client->try_delay);
if (msg_verbose)
msg_info("%s: new retry delay %d", myname, client->try_delay);
break;
default:
msg_panic("%s: bad name %d", myname, name);
}
}
va_end(ap);
}
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