unbound/testcode/asynclook.c

/*
 * testcode/asynclook.c - debug program perform async libunbound queries.
 *
 * Copyright (c) 2008, NLnet Labs. All rights reserved.
 *
 * This software is open source.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 * 
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * 
 * Neither the name of the NLNET LABS nor the names of its contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/**
 * \file
 *
 * This program shows the results from several background lookups,
 * while printing time in the foreground.
 */

#include "config.h"
#include "libunbound/unbound.h"
#include "util/locks.h"

/**
 * result list for the lookups
 */
struct lookinfo {
	/** name to look up */
	char* name;
	/** tracking number that can be used to cancel the query */
	int async_id;
	/** error code from libunbound */
	int err;
	/** result from lookup */
	struct ub_val_result* result;
};

/** global variable to see how many queries we have left */
static int num_wait = 0;

/** usage information for asynclook */
void usage(char* argv[])
{
	printf("usage: %s [options] name ...\n", argv[0]);
	printf("names are looked up at the same time, asynchronously.\n");
	printf("	-b : use blocking requests\n");
	printf("	-c : cancel the requests\n");
	printf("	-d : enable debug output\n");
	printf("	-f addr : use addr, forward to that server\n");
	printf("	-h : this help message\n");
	printf("	-r fname : read resolv.conf from fname\n");
	printf("	-t : use a resolver thread instead of forking a process\n");
	exit(1);
}

/** print result from lookup nicely */
static void
print_result(struct lookinfo* info)
{
	char buf[100];
	if(info->err) /* error (from libunbound) */
		printf("%s: error %s\n", info->name,
			ub_val_strerror(info->err));
	else if(!info->result)
		printf("%s: cancelled\n", info->name);
	else if(info->result->havedata)
		printf("%s: %s\n", info->name,
			inet_ntop(AF_INET, info->result->data[0],
			buf, (socklen_t)sizeof(buf)));
	else {
		/* there is no data, why that? */
		if(info->result->rcode == 0 /*noerror*/ ||
			info->result->nxdomain)
			printf("%s: no data %s\n", info->name,
			info->result->nxdomain?"(no such host)":
			"(no IP4 address)");
		else	/* some error (from the server) */
			printf("%s: DNS error %d\n", info->name,
				info->result->rcode);
	}
}

/** this is a function of type ub_val_callback_t */
void lookup_is_done(void* mydata, int err, struct ub_val_result* result)
{
	/* cast mydata back to the correct type */
	struct lookinfo* info = (struct lookinfo*)mydata;
	fprintf(stderr, "name %s resolved\n", info->name);
	info->err = err;
	info->result = result;
	/* one less to wait for */
	num_wait--;
}

/** check error, if bad, exit with error message */
static void checkerr(const char* desc, int err)
{
	if(err != 0) {
		printf("%s error: %s\n", desc, ub_val_strerror(err));
		exit(1);
	}
}

/** getopt global, in case header files fail to declare it. */
extern int optind;
/** getopt global, in case header files fail to declare it. */
extern char* optarg;

/** main program for asynclook */
int main(int argc, char** argv) 
{
	int c;
	struct ub_val_ctx* ctx;
	struct lookinfo* lookups;
	int i, r, cancel=0, blocking=0;

	/* lock debug start (if any) */
	checklock_start();

	/* create context */
	ctx = ub_val_ctx_create();
	if(!ctx) {
		printf("could not create context, %s\n", strerror(errno));
		return 1;
	}

	/* command line options */
	if(argc == 1) {
		usage(argv);
	}
	while( (c=getopt(argc, argv, "bcdf:hr:t")) != -1) {
		switch(c) {
			case 'd':
				r = ub_val_ctx_debuglevel(ctx, 3);
				checkerr("ub_val_ctx_debuglevel", r);
				break;
			case 't':
				r = ub_val_ctx_async(ctx, 1);
				checkerr("ub_val_ctx_async", r);
				break;
			case 'c':
				cancel = 1;
				break;
			case 'b':
				blocking = 1;
				break;
			case 'r':
				r = ub_val_ctx_resolvconf(ctx, optarg);
				if(r != 0) {
					printf("ub_val_ctx_resolvconf "
						"error: %s : %s\n",
						ub_val_strerror(r), 
						strerror(errno));
					return 1;
				}
				break;
			case 'f':
				r = ub_val_ctx_set_fwd(ctx, optarg);
				checkerr("ub_val_ctx_set_fwd", r);
				break;
			case 'h':
			case '?':
			default:
				usage(argv);
		}
	}
	argc -= optind;
	argv += optind;

	/* allocate array for results. */
	lookups = (struct lookinfo*)calloc((size_t)argc, 
		sizeof(struct lookinfo));
	if(!lookups) {
		printf("out of memory\n");
		return 1;
	}

	/* perform asyncronous calls */
	num_wait = argc;
	for(i=0; i<argc; i++) {
		lookups[i].name = argv[i];
		if(blocking) {
			fprintf(stderr, "lookup %s\n", argv[i]);
			r = ub_val_resolve(ctx, argv[i], LDNS_RR_TYPE_A,
				LDNS_RR_CLASS_IN, &lookups[i].result);
			checkerr("ub_val_resolve", r);
		} else {
			fprintf(stderr, "start async lookup %s\n", argv[i]);
			r = ub_val_resolve_async(ctx, argv[i], LDNS_RR_TYPE_A,
				LDNS_RR_CLASS_IN, &lookups[i], &lookup_is_done, 
				&lookups[i].async_id);
			checkerr("ub_val_resolve_async", r);
		}
	}
	if(blocking)
		num_wait = 0;
	else if(cancel) {
		for(i=0; i<argc; i++) {
			fprintf(stderr, "cancel %s\n", argv[i]);
			r = ub_val_cancel(ctx, lookups[i].async_id);
			checkerr("ub_val_cancel", r);
		}
		num_wait = 0;
	}

	/* wait while the hostnames are looked up. Do something useful here */
	if(num_wait > 0)
	    for(i=0; i<1000; i++) {
		usleep(100000);
		fprintf(stderr, "%g seconds passed\n", 0.1*(double)i);
		r = ub_val_process(ctx);
		checkerr("ub_val_process", r);
		if(num_wait == 0)
			break;
	}
	if(i>=999) {
		printf("timed out\n");
		return 0;
	}
	printf("lookup complete\n");

	/* print lookup results */
	for(i=0; i<argc; i++) {
		print_result(&lookups[i]);
		ub_val_result_free(lookups[i].result);
	}

	ub_val_ctx_delete(ctx);
	free(lookups);
	checklock_stop();
	return 0;
}