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GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	lib/libc/asr/asr.c	Lines:	0	342	0.0 %
Date:	2017-11-13	Branches:	0	285	0.0 %


/*	$OpenBSD: asr.c,v 1.57 2017/02/27 10:44:46 jca Exp $	*/
/*
 * Copyright (c) 2010-2012 Eric Faurot <eric@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>
#include <netdb.h>

#include <asr.h>
#include <errno.h>
#include <fcntl.h>
#include <resolv.h>
#include <poll.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>

#include "asr_private.h"

#include "thread_private.h"

#define DEFAULT_CONF		"lookup file\n"
#define DEFAULT_LOOKUP		"lookup bind file"

#define RELOAD_DELAY		15 /* seconds */

static void asr_check_reload(struct asr *);
static struct asr_ctx *asr_ctx_create(void);
static void asr_ctx_ref(struct asr_ctx *);
static void asr_ctx_free(struct asr_ctx *);
static int asr_ctx_add_searchdomain(struct asr_ctx *, const char *);
static int asr_ctx_from_file(struct asr_ctx *, const char *);
static int asr_ctx_from_string(struct asr_ctx *, const char *);
static int asr_ctx_parse(struct asr_ctx *, const char *);
static int asr_parse_nameserver(struct sockaddr *, const char *);
static int asr_ndots(const char *);
static void pass0(char **, int, struct asr_ctx *);
static int strsplit(char *, char **, int);
static void asr_ctx_envopts(struct asr_ctx *);
static void *__THREAD_NAME(_asr);

static struct asr *_asr = NULL;

/* Allocate and configure an async "resolver". */
static void *
_asr_resolver(void)
{
	static int	 init = 0;
	struct asr	*asr;

	if (init == 0) {
#ifdef DEBUG
		if (getenv("ASR_DEBUG"))
			_asr_debug = stderr;
#endif
		init = 1;
	}

	if ((asr = calloc(1, sizeof(*asr))) == NULL)
		goto fail;

	asr_check_reload(asr);
	if (asr->a_ctx == NULL) {
		if ((asr->a_ctx = asr_ctx_create()) == NULL)
			goto fail;
		if (asr_ctx_from_string(asr->a_ctx, DEFAULT_CONF) == -1)
			goto fail;
		asr_ctx_envopts(asr->a_ctx);
	}

#ifdef DEBUG
	_asr_dump_config(_asr_debug, asr);
#endif
	return (asr);

    fail:
	if (asr) {
		if (asr->a_ctx)
			asr_ctx_free(asr->a_ctx);
		free(asr);
	}

	return (NULL);
}

/*
 * Free the "asr" async resolver (or the thread-local resolver if NULL).
 * Drop the reference to the current context.
 */
void
_asr_resolver_done(void *arg)
{
	struct asr *asr = arg;
	struct asr **priv;

	if (asr == NULL) {
		priv = _THREAD_PRIVATE(_asr, _asr, &_asr);
		if (*priv == NULL)
			return;
		asr = *priv;
		*priv = NULL;
	}

	_asr_ctx_unref(asr->a_ctx);
	free(asr);
}

/*
 * Cancel an async query.
 */
void
asr_abort(struct asr_query *as)
{
	_asr_async_free(as);
}

/*
 * Resume the "as" async query resolution.  Return one of ASYNC_COND,
 * or ASYNC_DONE and put query-specific return values in the user-allocated
 * memory at "ar".
 */
int
asr_run(struct asr_query *as, struct asr_result *ar)
{
	int	r, saved_errno = errno;

	DPRINT("asr: asr_run(%p, %p) %s ctx=[%p]\n", as, ar,
	    _asr_querystr(as->as_type), as->as_ctx);
	r = as->as_run(as, ar);

	DPRINT("asr: asr_run(%p, %p) -> %s", as, ar, _asr_transitionstr(r));
#ifdef DEBUG
	if (r == ASYNC_COND)
#endif
		DPRINT(" fd=%i timeout=%i", ar->ar_fd, ar->ar_timeout);
	DPRINT("\n");
	if (r == ASYNC_DONE)
		_asr_async_free(as);

	errno = saved_errno;

	return (r);
}
DEF_WEAK(asr_run);

/*
 * Same as above, but run in a loop that handles the fd conditions result.
 */
int
asr_run_sync(struct asr_query *as, struct asr_result *ar)
{
	struct pollfd	 fds[1];
	struct timespec	 pollstart, pollend, elapsed;
	int		 timeout, r, p, saved_errno = errno;

	while ((r = asr_run(as, ar)) == ASYNC_COND) {
		fds[0].fd = ar->ar_fd;
		fds[0].events = (ar->ar_cond == ASR_WANT_READ) ? POLLIN:POLLOUT;

		timeout = ar->ar_timeout;
	again:
		if (clock_gettime(CLOCK_MONOTONIC, &pollstart))
			break;
		p = poll(fds, 1, timeout);
		if (p == -1 && errno == EINTR) {
			if (clock_gettime(CLOCK_MONOTONIC, &pollend))
				break;

			timespecsub(&pollend, &pollstart, &elapsed);
			timeout -= (elapsed.tv_sec * 1000) +
			    (elapsed.tv_nsec / 1000000);
			if (timeout < 1)
				break;
			goto again;
		}

		/*
		 * Otherwise, just ignore the error and let asr_run()
		 * catch the failure.
		 */
	}

	errno = saved_errno;

	return (r);
}
DEF_WEAK(asr_run_sync);

/*
 * Create a new async request of the given "type" on the async context "ac".
 * Take a reference on it so it does not gets deleted while the async query
 * is running.
 */
struct asr_query *
_asr_async_new(struct asr_ctx *ac, int type)
{
	struct asr_query	*as;

	DPRINT("asr: asr_async_new(ctx=%p) type=%i refcount=%i\n", ac, type,
	    ac ? ac->ac_refcount : 0);
	if (ac == NULL || (as = calloc(1, sizeof(*as))) == NULL)
		return (NULL);

	ac->ac_refcount += 1;
	as->as_ctx = ac;
	as->as_fd = -1;
	as->as_type = type;
	as->as_state = ASR_STATE_INIT;

	return (as);
}

/*
 * Free an async query and unref the associated context.
 */
void
_asr_async_free(struct asr_query *as)
{
	DPRINT("asr: asr_async_free(%p)\n", as);

	if (as->as_subq)
		_asr_async_free(as->as_subq);

	switch (as->as_type) {
	case ASR_SEND:
		if (as->as_fd != -1)
			close(as->as_fd);
		if (as->as.dns.obuf && !(as->as_flags & ASYNC_EXTOBUF))
			free(as->as.dns.obuf);
		if (as->as.dns.ibuf)
			free(as->as.dns.ibuf);
		if (as->as.dns.dname)
			free(as->as.dns.dname);
		break;

	case ASR_SEARCH:
		if (as->as.search.name)
			free(as->as.search.name);
		break;

	case ASR_GETRRSETBYNAME:
		if (as->as.rrset.name)
			free(as->as.rrset.name);
		break;

	case ASR_GETHOSTBYNAME:
	case ASR_GETHOSTBYADDR:
		if (as->as.hostnamadr.name)
			free(as->as.hostnamadr.name);
		break;

	case ASR_GETNETBYNAME:
	case ASR_GETNETBYADDR:
		if (as->as.netnamadr.name)
			free(as->as.netnamadr.name);
		break;

	case ASR_GETADDRINFO:
		if (as->as.ai.aifirst)
			freeaddrinfo(as->as.ai.aifirst);
		if (as->as.ai.hostname)
			free(as->as.ai.hostname);
		if (as->as.ai.servname)
			free(as->as.ai.servname);
		if (as->as.ai.fqdn)
			free(as->as.ai.fqdn);
		break;

	case ASR_GETNAMEINFO:
		break;
	}

	_asr_ctx_unref(as->as_ctx);
	free(as);
}

/*
 * Get a context from the given resolver. This takes a new reference to
 * the returned context, which *must* be explicitely dropped when done
 * using this context.
 */
struct asr_ctx *
_asr_use_resolver(void *arg)
{
	struct asr *asr = arg;
	struct asr **priv;

	if (asr == NULL) {
		DPRINT("using thread-local resolver\n");
		priv = _THREAD_PRIVATE(_asr, _asr, &_asr);
		if (*priv == NULL) {
			DPRINT("setting up thread-local resolver\n");
			*priv = _asr_resolver();
		}
		asr = *priv;
	}
	if (asr != NULL) {
		asr_check_reload(asr);
		asr_ctx_ref(asr->a_ctx);
		return (asr->a_ctx);
	}
	return (NULL);
}

static void
asr_ctx_ref(struct asr_ctx *ac)
{
	DPRINT("asr: asr_ctx_ref(ctx=%p) refcount=%i\n", ac, ac->ac_refcount);
	ac->ac_refcount += 1;
}

/*
 * Drop a reference to an async context, freeing it if the reference
 * count drops to 0.
 */
void
_asr_ctx_unref(struct asr_ctx *ac)
{
	DPRINT("asr: asr_ctx_unref(ctx=%p) refcount=%i\n", ac,
	    ac ? ac->ac_refcount : 0);
	if (ac == NULL)
		return;
	if (--ac->ac_refcount)
		return;

	asr_ctx_free(ac);
}

static void
asr_ctx_free(struct asr_ctx *ac)
{
	int i;

	if (ac->ac_domain)
		free(ac->ac_domain);
	for (i = 0; i < ASR_MAXNS; i++)
		free(ac->ac_ns[i]);
	for (i = 0; i < ASR_MAXDOM; i++)
		free(ac->ac_dom[i]);

	free(ac);
}

/*
 * Reload the configuration file if it has changed on disk.
 */
static void
asr_check_reload(struct asr *asr)
{
	struct asr_ctx	*ac;
	struct stat	 st;
	struct timespec	 ts;
	pid_t		 pid;

	pid = getpid();
	if (pid != asr->a_pid) {
		asr->a_pid = pid;
		asr->a_rtime = 0;
	}

	if (clock_gettime(CLOCK_MONOTONIC, &ts) == -1)
		return;

	if ((ts.tv_sec - asr->a_rtime) < RELOAD_DELAY && asr->a_rtime != 0)
		return;
	asr->a_rtime = ts.tv_sec;

	DPRINT("asr: checking for update of \"%s\"\n", _PATH_RESCONF);
	if (stat(_PATH_RESCONF, &st) == -1 ||
	    asr->a_mtime == st.st_mtime ||
	    (ac = asr_ctx_create()) == NULL)
		return;
	asr->a_mtime = st.st_mtime;

	DPRINT("asr: reloading config file\n");
	if (asr_ctx_from_file(ac, _PATH_RESCONF) == -1) {
		asr_ctx_free(ac);
		return;
	}

	asr_ctx_envopts(ac);
	if (asr->a_ctx)
		_asr_ctx_unref(asr->a_ctx);
	asr->a_ctx = ac;
}

/*
 * Construct a fully-qualified domain name for the given name and domain.
 * If "name" ends with a '.' it is considered as a FQDN by itself.
 * Otherwise, the domain, which must be a FQDN, is appended to "name" (it
 * may have a leading dot which would be ignored). If the domain is null,
 * then "." is used. Return the length of the constructed FQDN or (0) on
 * error.
 */
size_t
_asr_make_fqdn(const char *name, const char *domain, char *buf, size_t buflen)
{
	size_t	len;

	if (domain == NULL)
		domain = ".";
	else if ((len = strlen(domain)) == 0)
		return (0);
	else if (domain[len -1] != '.')
		return (0);

	len = strlen(name);
	if (len == 0) {
		if (strlcpy(buf, domain, buflen) >= buflen)
			return (0);
	} else if (name[len - 1] !=  '.') {
		if (domain[0] == '.')
			domain += 1;
		if (strlcpy(buf, name, buflen) >= buflen ||
		    strlcat(buf, ".", buflen) >= buflen ||
		    strlcat(buf, domain, buflen) >= buflen)
			return (0);
	} else {
		if (strlcpy(buf, name, buflen) >= buflen)
			return (0);
	}

	return (strlen(buf));
}

/*
 * Count the dots in a string.
 */
static int
asr_ndots(const char *s)
{
	int n;

	for (n = 0; *s; s++)
		if (*s == '.')
			n += 1;

	return (n);
}

/*
 * Allocate a new empty context.
 */
static struct asr_ctx *
asr_ctx_create(void)
{
	struct asr_ctx	*ac;

	if ((ac = calloc(1, sizeof(*ac))) == NULL)
		return (NULL);

	ac->ac_options = RES_RECURSE | RES_DEFNAMES | RES_DNSRCH;
	ac->ac_refcount = 1;
	ac->ac_ndots = 1;
	ac->ac_family[0] = AF_INET;
	ac->ac_family[1] = AF_INET6;
	ac->ac_family[2] = -1;

	ac->ac_nscount = 0;
	ac->ac_nstimeout = 5;
	ac->ac_nsretries = 4;

	return (ac);
}

struct asr_ctx *
_asr_no_resolver(void)
{
	return asr_ctx_create();
}

/*
 * Add a search domain to the async context.
 */
static int
asr_ctx_add_searchdomain(struct asr_ctx *ac, const char *domain)
{
	char buf[MAXDNAME];

	if (ac->ac_domcount == ASR_MAXDOM)
		return (-1);

	if (_asr_make_fqdn(domain, NULL, buf, sizeof(buf)) == 0)
		return (-1);

	if ((ac->ac_dom[ac->ac_domcount] = strdup(buf)) == NULL)
		return (0);

	ac->ac_domcount += 1;

	return (1);
}

static int
strsplit(char *line, char **tokens, int ntokens)
{
	int	ntok;
	char	*cp, **tp;

	for (cp = line, tp = tokens, ntok = 0;
	    ntok < ntokens && (*tp = strsep(&cp, " \t")) != NULL; )
		if (**tp != '\0') {
			tp++;
			ntok++;
		}

	return (ntok);
}

/*
 * Pass on a split config line.
 */
static void
pass0(char **tok, int n, struct asr_ctx *ac)
{
	int		 i, j, d;
	const char	*e;
	struct sockaddr_storage	ss;

	if (!strcmp(tok[0], "nameserver")) {
		if (ac->ac_nscount == ASR_MAXNS)
			return;
		if (n != 2)
			return;
		if (asr_parse_nameserver((struct sockaddr *)&ss, tok[1]))
			return;
		if ((ac->ac_ns[ac->ac_nscount] = calloc(1, ss.ss_len)) == NULL)
			return;
		memmove(ac->ac_ns[ac->ac_nscount], &ss, ss.ss_len);
		ac->ac_nscount += 1;

	} else if (!strcmp(tok[0], "domain")) {
		if (n != 2)
			return;
		if (ac->ac_domain)
			return;
		ac->ac_domain = strdup(tok[1]);

	} else if (!strcmp(tok[0], "lookup")) {
		/* ensure that each lookup is only given once */
		for (i = 1; i < n; i++)
			for (j = i + 1; j < n; j++)
				if (!strcmp(tok[i], tok[j]))
					return;
		ac->ac_dbcount = 0;
		for (i = 1; i < n && ac->ac_dbcount < ASR_MAXDB; i++) {
			if (!strcmp(tok[i], "yp")) {
				/* silently deprecated */
			} else if (!strcmp(tok[i], "bind"))
				ac->ac_db[ac->ac_dbcount++] = ASR_DB_DNS;
			else if (!strcmp(tok[i], "file"))
				ac->ac_db[ac->ac_dbcount++] = ASR_DB_FILE;
		}
	} else if (!strcmp(tok[0], "search")) {
		/* resolv.conf says the last line wins */
		for (i = 0; i < ASR_MAXDOM; i++) {
			free(ac->ac_dom[i]);
			ac->ac_dom[i] = NULL;
		}
		ac->ac_domcount = 0;
		for (i = 1; i < n; i++)
			asr_ctx_add_searchdomain(ac, tok[i]);

	} else if (!strcmp(tok[0], "family")) {
		if (n == 1 || n > 3)
			return;
		for (i = 1; i < n; i++)
			if (strcmp(tok[i], "inet4") && strcmp(tok[i], "inet6"))
				return;
		for (i = 1; i < n; i++)
			ac->ac_family[i - 1] = strcmp(tok[i], "inet4") ? \
			    AF_INET6 : AF_INET;
		ac->ac_family[i - 1] = -1;

	} else if (!strcmp(tok[0], "options")) {
		for (i = 1; i < n; i++) {
			if (!strcmp(tok[i], "tcp"))
				ac->ac_options |= RES_USEVC;
			else if (!strcmp(tok[i], "edns0"))
				ac->ac_options |= RES_USE_EDNS0;
			else if ((!strncmp(tok[i], "ndots:", 6))) {
				e = NULL;
				d = strtonum(tok[i] + 6, 1, 16, &e);
				if (e == NULL)
					ac->ac_ndots = d;
			}
		}
	}
}

/*
 * Setup an async context with the config specified in the string "str".
 */
static int
asr_ctx_from_string(struct asr_ctx *ac, const char *str)
{
	char		 buf[512], *ch;

	asr_ctx_parse(ac, str);

	if (ac->ac_dbcount == 0) {
		/* No lookup directive */
		asr_ctx_parse(ac, DEFAULT_LOOKUP);
	}

	if (ac->ac_nscount == 0)
		asr_ctx_parse(ac, "nameserver 127.0.0.1");

	if (ac->ac_domain == NULL)
		if (gethostname(buf, sizeof buf) == 0) {
			ch = strchr(buf, '.');
			if (ch)
				ac->ac_domain = strdup(ch + 1);
			else /* Assume root. see resolv.conf(5) */
				ac->ac_domain = strdup("");
		}

	/* If no search domain was specified, use the local subdomains */
	if (ac->ac_domcount == 0)
		for (ch = ac->ac_domain; ch; ) {
			asr_ctx_add_searchdomain(ac, ch);
			ch = strchr(ch, '.');
			if (ch && asr_ndots(++ch) == 0)
				break;
		}

	return (0);
}

/*
 * Setup the "ac" async context from the file at location "path".
 */
static int
asr_ctx_from_file(struct asr_ctx *ac, const char *path)
{
	FILE	*cf;
	char	 buf[4096];
	ssize_t	 r;

	cf = fopen(path, "re");
	if (cf == NULL)
		return (-1);

	r = fread(buf, 1, sizeof buf - 1, cf);
	if (feof(cf) == 0) {
		DPRINT("asr: config file too long: \"%s\"\n", path);
		r = -1;
	}
	fclose(cf);
	if (r == -1)
		return (-1);
	buf[r] = '\0';

	return asr_ctx_from_string(ac, buf);
}

/*
 * Parse lines in the configuration string. For each one, split it into
 * tokens and pass them to "pass0" for processing.
 */
static int
asr_ctx_parse(struct asr_ctx *ac, const char *str)
{
	size_t		 len;
	const char	*line;
	char		 buf[1024];
	char		*tok[10];
	int		 ntok;

	line = str;
	while (*line) {
		len = strcspn(line, "\n\0");
		if (len < sizeof buf) {
			memmove(buf, line, len);
			buf[len] = '\0';
		} else
			buf[0] = '\0';
		line += len;
		if (*line == '\n')
			line++;
		buf[strcspn(buf, ";#")] = '\0';
		if ((ntok = strsplit(buf, tok, 10)) == 0)
			continue;

		pass0(tok, ntok, ac);
	}

	return (0);
}

/*
 * Check for environment variables altering the configuration as described
 * in resolv.conf(5).  Although not documented there, this feature is disabled
 * for setuid/setgid programs.
 */
static void
asr_ctx_envopts(struct asr_ctx *ac)
{
	char	buf[4096], *e;
	size_t	s;

	if (issetugid()) {
		ac->ac_options |= RES_NOALIASES;
		return;
	}

	if ((e = getenv("RES_OPTIONS")) != NULL) {
		strlcpy(buf, "options ", sizeof buf);
		strlcat(buf, e, sizeof buf);
		s = strlcat(buf, "\n", sizeof buf);
		if (s < sizeof buf)
			asr_ctx_parse(ac, buf);
	}

	if ((e = getenv("LOCALDOMAIN")) != NULL) {
		strlcpy(buf, "search ", sizeof buf);
		strlcat(buf, e, sizeof buf);
		s = strlcat(buf, "\n", sizeof buf);
		if (s < sizeof buf)
			asr_ctx_parse(ac, buf);
	}
}

/*
 * Parse a resolv.conf(5) nameserver string into a sockaddr.
 */
static int
asr_parse_nameserver(struct sockaddr *sa, const char *s)
{
	in_port_t	 portno = 53;

	if (_asr_sockaddr_from_str(sa, PF_UNSPEC, s) == -1)
		return (-1);

	if (sa->sa_family == PF_INET)
		((struct sockaddr_in *)sa)->sin_port = htons(portno);
	else if (sa->sa_family == PF_INET6)
		((struct sockaddr_in6 *)sa)->sin6_port = htons(portno);

	return (0);
}

/*
 * Turn a (uncompressed) DNS domain name into a regular nul-terminated string
 * where labels are separated by dots. The result is put into the "buf" buffer,
 * truncated if it exceeds "max" chars. The function returns "buf".
 */
char *
_asr_strdname(const char *_dname, char *buf, size_t max)
{
	const unsigned char *dname = _dname;
	char	*res;
	size_t	 left, n, count;

	if (_dname[0] == 0) {
		strlcpy(buf, ".", max);
		return buf;
	}

	res = buf;
	left = max - 1;
	for (n = 0; dname[0] && left; n += dname[0]) {
		count = (dname[0] < (left - 1)) ? dname[0] : (left - 1);
		memmove(buf, dname + 1, count);
		dname += dname[0] + 1;
		left -= count;
		buf += count;
		if (left) {
			left -= 1;
			*buf++ = '.';
		}
	}
	buf[0] = 0;

	return (res);
}

/*
 * Read and split the next line from the given namedb file.
 * Return -1 on error, or put the result in the "tokens" array of
 * size "ntoken" and returns the number of token on the line.
 */
int
_asr_parse_namedb_line(FILE *file, char **tokens, int ntoken, char *lbuf, size_t sz)
{
	size_t	  len;
	char	 *buf;
	int	  ntok;

    again:
	if ((buf = fgetln(file, &len)) == NULL)
		return (-1);

	if (len >= sz)
		goto again;

	if (buf[len - 1] == '\n')
		len--;
	else {
		memcpy(lbuf, buf, len);
		buf = lbuf;
	}

	buf[len] = '\0';
	buf[strcspn(buf, "#")] = '\0';
	if ((ntok = strsplit(buf, tokens, ntoken)) == 0)
		goto again;

	return (ntok);
}

/*
 * Update the async context so that it uses the next configured DB.
 * Return 0 on success, or -1 if no more DBs is available.
 */
int
_asr_iter_db(struct asr_query *as)
{
	if (as->as_db_idx >= as->as_ctx->ac_dbcount) {
		DPRINT("asr_iter_db: done\n");
		return (-1);
	}

	as->as_db_idx += 1;
	DPRINT("asr_iter_db: %i\n", as->as_db_idx);

	return (0);
}


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: asr.c,v 1.57 2017/02/27 10:44:46 jca Exp $ */
2			/*
3			* Copyright (c) 2010-2012 Eric Faurot <eric@openbsd.org>
4			*
5			* Permission to use, copy, modify, and distribute this software for any
6			* purpose with or without fee is hereby granted, provided that the above
7			* copyright notice and this permission notice appear in all copies.
8			*
9			* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10			* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11			* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12			* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13			* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14			* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15			* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16			*/
17
18			#include <sys/types.h>
19			#include <sys/socket.h>
20			#include <sys/stat.h>
21			#include <netinet/in.h>
22			#include <arpa/inet.h>
23			#include <arpa/nameser.h>
24			#include <netdb.h>
25
26			#include <asr.h>
27			#include <errno.h>
28			#include <fcntl.h>
29			#include <resolv.h>
30			#include <poll.h>
31			#include <stdio.h>
32			#include <stdlib.h>
33			#include <string.h>
34			#include <unistd.h>
35			#include <limits.h>
36
37			#include "asr_private.h"
38
39			#include "thread_private.h"
40
41			#define DEFAULT_CONF "lookup file\n"
42			#define DEFAULT_LOOKUP "lookup bind file"
43
44			#define RELOAD_DELAY 15 /* seconds */
45
46			static void asr_check_reload(struct asr *);
47			static struct asr_ctx *asr_ctx_create(void);
48			static void asr_ctx_ref(struct asr_ctx *);
49			static void asr_ctx_free(struct asr_ctx *);
50			static int asr_ctx_add_searchdomain(struct asr_ctx , const char );
51			static int asr_ctx_from_file(struct asr_ctx , const char );
52			static int asr_ctx_from_string(struct asr_ctx , const char );
53			static int asr_ctx_parse(struct asr_ctx , const char );
54			static int asr_parse_nameserver(struct sockaddr , const char );
55			static int asr_ndots(const char *);
56			static void pass0(char *, int, struct asr_ctx );
57			static int strsplit(char , char *, int);
58			static void asr_ctx_envopts(struct asr_ctx *);
59			static void *__THREAD_NAME(_asr);
60
61			static struct asr *_asr = NULL;
62
63			/* Allocate and configure an async "resolver". */
64			static void *
65			_asr_resolver(void)
66			{
67			static int init = 0;
68			struct asr *asr;
69
70			if (init == 0) {
71			#ifdef DEBUG
72			if (getenv("ASR_DEBUG"))
73			_asr_debug = stderr;
74			#endif
75			init = 1;
76			}
77
78			if ((asr = calloc(1, sizeof(*asr))) == NULL)
79			goto fail;
80
81			asr_check_reload(asr);
82			if (asr->a_ctx == NULL) {
83			if ((asr->a_ctx = asr_ctx_create()) == NULL)
84			goto fail;
85			if (asr_ctx_from_string(asr->a_ctx, DEFAULT_CONF) == -1)
86			goto fail;
87			asr_ctx_envopts(asr->a_ctx);
88			}
89
90			#ifdef DEBUG
91			_asr_dump_config(_asr_debug, asr);
92			#endif
93			return (asr);
94
95			fail:
96			if (asr) {
97			if (asr->a_ctx)
98			asr_ctx_free(asr->a_ctx);
99			free(asr);
100			}
101
102			return (NULL);
103			}
104
105			/*
106			* Free the "asr" async resolver (or the thread-local resolver if NULL).
107			* Drop the reference to the current context.
108			*/
109			void
110			_asr_resolver_done(void *arg)
111			{
112			struct asr *asr = arg;
113			struct asr **priv;
114
115			if (asr == NULL) {
116			priv = _THREAD_PRIVATE(_asr, _asr, &_asr);
117			if (*priv == NULL)
118			return;
119			asr = *priv;
120			*priv = NULL;
121			}
122
123			_asr_ctx_unref(asr->a_ctx);
124			free(asr);
125			}
126
127			/*
128			* Cancel an async query.
129			*/
130			void
131			asr_abort(struct asr_query *as)
132			{
133			_asr_async_free(as);
134			}
135
136			/*
137			* Resume the "as" async query resolution. Return one of ASYNC_COND,
138			* or ASYNC_DONE and put query-specific return values in the user-allocated
139			* memory at "ar".
140			*/
141			int
142			asr_run(struct asr_query as, struct asr_result ar)
143			{
144			int r, saved_errno = errno;
145
146			DPRINT("asr: asr_run(%p, %p) %s ctx=[%p]\n", as, ar,
147			_asr_querystr(as->as_type), as->as_ctx);
148			r = as->as_run(as, ar);
149
150			DPRINT("asr: asr_run(%p, %p) -> %s", as, ar, _asr_transitionstr(r));
151			#ifdef DEBUG
152			if (r == ASYNC_COND)
153			#endif
154			DPRINT(" fd=%i timeout=%i", ar->ar_fd, ar->ar_timeout);
155			DPRINT("\n");
156			if (r == ASYNC_DONE)
157			_asr_async_free(as);
158
159			errno = saved_errno;
160
161			return (r);
162			}
163			DEF_WEAK(asr_run);
164
165			/*
166			* Same as above, but run in a loop that handles the fd conditions result.
167			*/
168			int
169			asr_run_sync(struct asr_query as, struct asr_result ar)
170			{
171			struct pollfd fds[1];
172			struct timespec pollstart, pollend, elapsed;
173			int timeout, r, p, saved_errno = errno;
174
175			while ((r = asr_run(as, ar)) == ASYNC_COND) {
176			fds[0].fd = ar->ar_fd;
177			fds[0].events = (ar->ar_cond == ASR_WANT_READ) ? POLLIN:POLLOUT;
178
179			timeout = ar->ar_timeout;
180			again:
181			if (clock_gettime(CLOCK_MONOTONIC, &pollstart))
182			break;
183			p = poll(fds, 1, timeout);
184			if (p == -1 && errno == EINTR) {
185			if (clock_gettime(CLOCK_MONOTONIC, &pollend))
186			break;
187
188			timespecsub(&pollend, &pollstart, &elapsed);
189			timeout -= (elapsed.tv_sec * 1000) +
190			(elapsed.tv_nsec / 1000000);
191			if (timeout < 1)
192			break;
193			goto again;
194			}
195
196			/*
197			* Otherwise, just ignore the error and let asr_run()
198			* catch the failure.
199			*/
200			}
201
202			errno = saved_errno;
203
204			return (r);
205			}
206			DEF_WEAK(asr_run_sync);
207
208			/*
209			* Create a new async request of the given "type" on the async context "ac".
210			* Take a reference on it so it does not gets deleted while the async query
211			* is running.
212			*/
213			struct asr_query *
214			_asr_async_new(struct asr_ctx *ac, int type)
215			{
216			struct asr_query *as;
217
218			DPRINT("asr: asr_async_new(ctx=%p) type=%i refcount=%i\n", ac, type,
219			ac ? ac->ac_refcount : 0);
220			if (ac == NULL \|\| (as = calloc(1, sizeof(*as))) == NULL)
221			return (NULL);
222
223			ac->ac_refcount += 1;
224			as->as_ctx = ac;
225			as->as_fd = -1;
226			as->as_type = type;
227			as->as_state = ASR_STATE_INIT;
228
229			return (as);
230			}
231
232			/*
233			* Free an async query and unref the associated context.
234			*/
235			void
236			_asr_async_free(struct asr_query *as)
237			{
238			DPRINT("asr: asr_async_free(%p)\n", as);
239
240			if (as->as_subq)
241			_asr_async_free(as->as_subq);
242
243			switch (as->as_type) {
244			case ASR_SEND:
245			if (as->as_fd != -1)
246			close(as->as_fd);
247			if (as->as.dns.obuf && !(as->as_flags & ASYNC_EXTOBUF))
248			free(as->as.dns.obuf);
249			if (as->as.dns.ibuf)
250			free(as->as.dns.ibuf);
251			if (as->as.dns.dname)
252			free(as->as.dns.dname);
253			break;
254
255			case ASR_SEARCH:
256			if (as->as.search.name)
257			free(as->as.search.name);
258			break;
259
260			case ASR_GETRRSETBYNAME:
261			if (as->as.rrset.name)
262			free(as->as.rrset.name);
263			break;
264
265			case ASR_GETHOSTBYNAME:
266			case ASR_GETHOSTBYADDR:
267			if (as->as.hostnamadr.name)
268			free(as->as.hostnamadr.name);
269			break;
270
271			case ASR_GETNETBYNAME:
272			case ASR_GETNETBYADDR:
273			if (as->as.netnamadr.name)
274			free(as->as.netnamadr.name);
275			break;
276
277			case ASR_GETADDRINFO:
278			if (as->as.ai.aifirst)
279			freeaddrinfo(as->as.ai.aifirst);
280			if (as->as.ai.hostname)
281			free(as->as.ai.hostname);
282			if (as->as.ai.servname)
283			free(as->as.ai.servname);
284			if (as->as.ai.fqdn)
285			free(as->as.ai.fqdn);
286			break;
287
288			case ASR_GETNAMEINFO:
289			break;
290			}
291
292			_asr_ctx_unref(as->as_ctx);
293			free(as);
294			}
295
296			/*
297			* Get a context from the given resolver. This takes a new reference to
298			* the returned context, which must be explicitely dropped when done
299			* using this context.
300			*/
301			struct asr_ctx *
302			_asr_use_resolver(void *arg)
303			{
304			struct asr *asr = arg;
305			struct asr **priv;
306
307			if (asr == NULL) {
308			DPRINT("using thread-local resolver\n");
309			priv = _THREAD_PRIVATE(_asr, _asr, &_asr);
310			if (*priv == NULL) {
311			DPRINT("setting up thread-local resolver\n");
312			*priv = _asr_resolver();
313			}
314			asr = *priv;
315			}
316			if (asr != NULL) {
317			asr_check_reload(asr);
318			asr_ctx_ref(asr->a_ctx);
319			return (asr->a_ctx);
320			}
321			return (NULL);
322			}
323
324			static void
325			asr_ctx_ref(struct asr_ctx *ac)
326			{
327			DPRINT("asr: asr_ctx_ref(ctx=%p) refcount=%i\n", ac, ac->ac_refcount);
328			ac->ac_refcount += 1;
329			}
330
331			/*
332			* Drop a reference to an async context, freeing it if the reference
333			* count drops to 0.
334			*/
335			void
336			_asr_ctx_unref(struct asr_ctx *ac)
337			{
338			DPRINT("asr: asr_ctx_unref(ctx=%p) refcount=%i\n", ac,
339			ac ? ac->ac_refcount : 0);
340			if (ac == NULL)
341			return;
342			if (--ac->ac_refcount)
343			return;
344
345			asr_ctx_free(ac);
346			}
347
348			static void
349			asr_ctx_free(struct asr_ctx *ac)
350			{
351			int i;
352
353			if (ac->ac_domain)
354			free(ac->ac_domain);
355			for (i = 0; i < ASR_MAXNS; i++)
356			free(ac->ac_ns[i]);
357			for (i = 0; i < ASR_MAXDOM; i++)
358			free(ac->ac_dom[i]);
359
360			free(ac);
361			}
362
363			/*
364			* Reload the configuration file if it has changed on disk.
365			*/
366			static void
367			asr_check_reload(struct asr *asr)
368			{
369			struct asr_ctx *ac;
370			struct stat st;
371			struct timespec ts;
372			pid_t pid;
373
374			pid = getpid();
375			if (pid != asr->a_pid) {
376			asr->a_pid = pid;
377			asr->a_rtime = 0;
378			}
379
380			if (clock_gettime(CLOCK_MONOTONIC, &ts) == -1)
381			return;
382
383			if ((ts.tv_sec - asr->a_rtime) < RELOAD_DELAY && asr->a_rtime != 0)
384			return;
385			asr->a_rtime = ts.tv_sec;
386
387			DPRINT("asr: checking for update of \"%s\"\n", _PATH_RESCONF);
388			if (stat(_PATH_RESCONF, &st) == -1 \|\|
389			asr->a_mtime == st.st_mtime \|\|
390			(ac = asr_ctx_create()) == NULL)
391			return;
392			asr->a_mtime = st.st_mtime;
393
394			DPRINT("asr: reloading config file\n");
395			if (asr_ctx_from_file(ac, _PATH_RESCONF) == -1) {
396			asr_ctx_free(ac);
397			return;
398			}
399
400			asr_ctx_envopts(ac);
401			if (asr->a_ctx)
402			_asr_ctx_unref(asr->a_ctx);
403			asr->a_ctx = ac;
404			}
405
406			/*
407			* Construct a fully-qualified domain name for the given name and domain.
408			* If "name" ends with a '.' it is considered as a FQDN by itself.
409			* Otherwise, the domain, which must be a FQDN, is appended to "name" (it
410			* may have a leading dot which would be ignored). If the domain is null,
411			* then "." is used. Return the length of the constructed FQDN or (0) on
412			* error.
413			*/
414			size_t
415			_asr_make_fqdn(const char name, const char domain, char *buf, size_t buflen)
416			{
417			size_t len;
418
419			if (domain == NULL)
420			domain = ".";
421			else if ((len = strlen(domain)) == 0)
422			return (0);
423			else if (domain[len -1] != '.')
424			return (0);
425
426			len = strlen(name);
427			if (len == 0) {
428			if (strlcpy(buf, domain, buflen) >= buflen)
429			return (0);
430			} else if (name[len - 1] != '.') {
431			if (domain[0] == '.')
432			domain += 1;
433			if (strlcpy(buf, name, buflen) >= buflen \|\|
434			strlcat(buf, ".", buflen) >= buflen \|\|
435			strlcat(buf, domain, buflen) >= buflen)
436			return (0);
437			} else {
438			if (strlcpy(buf, name, buflen) >= buflen)
439			return (0);
440			}
441
442			return (strlen(buf));
443			}
444
445			/*
446			* Count the dots in a string.
447			*/
448			static int
449			asr_ndots(const char *s)
450			{
451			int n;
452
453			for (n = 0; *s; s++)
454			if (*s == '.')
455			n += 1;
456
457			return (n);
458			}
459
460			/*
461			* Allocate a new empty context.
462			*/
463			static struct asr_ctx *
464			asr_ctx_create(void)
465			{
466			struct asr_ctx *ac;
467
468			if ((ac = calloc(1, sizeof(*ac))) == NULL)
469			return (NULL);
470
471			ac->ac_options = RES_RECURSE \| RES_DEFNAMES \| RES_DNSRCH;
472			ac->ac_refcount = 1;
473			ac->ac_ndots = 1;
474			ac->ac_family[0] = AF_INET;
475			ac->ac_family[1] = AF_INET6;
476			ac->ac_family[2] = -1;
477
478			ac->ac_nscount = 0;
479			ac->ac_nstimeout = 5;
480			ac->ac_nsretries = 4;
481
482			return (ac);
483			}
484
485			struct asr_ctx *
486			_asr_no_resolver(void)
487			{
488			return asr_ctx_create();
489			}
490
491			/*
492			* Add a search domain to the async context.
493			*/
494			static int
495			asr_ctx_add_searchdomain(struct asr_ctx ac, const char domain)
496			{
497			char buf[MAXDNAME];
498
499			if (ac->ac_domcount == ASR_MAXDOM)
500			return (-1);
501
502			if (_asr_make_fqdn(domain, NULL, buf, sizeof(buf)) == 0)
503			return (-1);
504
505			if ((ac->ac_dom[ac->ac_domcount] = strdup(buf)) == NULL)
506			return (0);
507
508			ac->ac_domcount += 1;
509
510			return (1);
511			}
512
513			static int
514			strsplit(char line, char *tokens, int ntokens)
515			{
516			int ntok;
517			char cp, *tp;
518
519			for (cp = line, tp = tokens, ntok = 0;
520			ntok < ntokens && (*tp = strsep(&cp, " \t")) != NULL; )
521			if (**tp != '\0') {
522			tp++;
523			ntok++;
524			}
525
526			return (ntok);
527			}
528
529			/*
530			* Pass on a split config line.
531			*/
532			static void
533			pass0(char *tok, int n, struct asr_ctx ac)
534			{
535			int i, j, d;
536			const char *e;
537			struct sockaddr_storage ss;
538
539			if (!strcmp(tok[0], "nameserver")) {
540			if (ac->ac_nscount == ASR_MAXNS)
541			return;
542			if (n != 2)
543			return;
544			if (asr_parse_nameserver((struct sockaddr *)&ss, tok[1]))
545			return;
546			if ((ac->ac_ns[ac->ac_nscount] = calloc(1, ss.ss_len)) == NULL)
547			return;
548			memmove(ac->ac_ns[ac->ac_nscount], &ss, ss.ss_len);
549			ac->ac_nscount += 1;
550
551			} else if (!strcmp(tok[0], "domain")) {
552			if (n != 2)
553			return;
554			if (ac->ac_domain)
555			return;
556			ac->ac_domain = strdup(tok[1]);
557
558			} else if (!strcmp(tok[0], "lookup")) {
559			/* ensure that each lookup is only given once */
560			for (i = 1; i < n; i++)
561			for (j = i + 1; j < n; j++)
562			if (!strcmp(tok[i], tok[j]))
563			return;
564			ac->ac_dbcount = 0;
565			for (i = 1; i < n && ac->ac_dbcount < ASR_MAXDB; i++) {
566			if (!strcmp(tok[i], "yp")) {
567			/* silently deprecated */
568			} else if (!strcmp(tok[i], "bind"))
569			ac->ac_db[ac->ac_dbcount++] = ASR_DB_DNS;
570			else if (!strcmp(tok[i], "file"))
571			ac->ac_db[ac->ac_dbcount++] = ASR_DB_FILE;
572			}
573			} else if (!strcmp(tok[0], "search")) {
574			/* resolv.conf says the last line wins */
575			for (i = 0; i < ASR_MAXDOM; i++) {
576			free(ac->ac_dom[i]);
577			ac->ac_dom[i] = NULL;
578			}
579			ac->ac_domcount = 0;
580			for (i = 1; i < n; i++)
581			asr_ctx_add_searchdomain(ac, tok[i]);
582
583			} else if (!strcmp(tok[0], "family")) {
584			if (n == 1 \|\| n > 3)
585			return;
586			for (i = 1; i < n; i++)
587			if (strcmp(tok[i], "inet4") && strcmp(tok[i], "inet6"))
588			return;
589			for (i = 1; i < n; i++)
590			ac->ac_family[i - 1] = strcmp(tok[i], "inet4") ? \
591			AF_INET6 : AF_INET;
592			ac->ac_family[i - 1] = -1;
593
594			} else if (!strcmp(tok[0], "options")) {
595			for (i = 1; i < n; i++) {
596			if (!strcmp(tok[i], "tcp"))
597			ac->ac_options \|= RES_USEVC;
598			else if (!strcmp(tok[i], "edns0"))
599			ac->ac_options \|= RES_USE_EDNS0;
600			else if ((!strncmp(tok[i], "ndots:", 6))) {
601			e = NULL;
602			d = strtonum(tok[i] + 6, 1, 16, &e);
603			if (e == NULL)
604			ac->ac_ndots = d;
605			}
606			}
607			}
608			}
609
610			/*
611			* Setup an async context with the config specified in the string "str".
612			*/
613			static int
614			asr_ctx_from_string(struct asr_ctx ac, const char str)
615			{
616			char buf[512], *ch;
617
618			asr_ctx_parse(ac, str);
619
620			if (ac->ac_dbcount == 0) {
621			/* No lookup directive */
622			asr_ctx_parse(ac, DEFAULT_LOOKUP);
623			}
624
625			if (ac->ac_nscount == 0)
626			asr_ctx_parse(ac, "nameserver 127.0.0.1");
627
628			if (ac->ac_domain == NULL)
629			if (gethostname(buf, sizeof buf) == 0) {
630			ch = strchr(buf, '.');
631			if (ch)
632			ac->ac_domain = strdup(ch + 1);
633			else /* Assume root. see resolv.conf(5) */
634			ac->ac_domain = strdup("");
635			}
636
637			/* If no search domain was specified, use the local subdomains */
638			if (ac->ac_domcount == 0)
639			for (ch = ac->ac_domain; ch; ) {
640			asr_ctx_add_searchdomain(ac, ch);
641			ch = strchr(ch, '.');
642			if (ch && asr_ndots(++ch) == 0)
643			break;
644			}
645
646			return (0);
647			}
648
649			/*
650			* Setup the "ac" async context from the file at location "path".
651			*/
652			static int
653			asr_ctx_from_file(struct asr_ctx ac, const char path)
654			{
655			FILE *cf;
656			char buf[4096];
657			ssize_t r;
658
659			cf = fopen(path, "re");
660			if (cf == NULL)
661			return (-1);
662
663			r = fread(buf, 1, sizeof buf - 1, cf);
664			if (feof(cf) == 0) {
665			DPRINT("asr: config file too long: \"%s\"\n", path);
666			r = -1;
667			}
668			fclose(cf);
669			if (r == -1)
670			return (-1);
671			buf[r] = '\0';
672
673			return asr_ctx_from_string(ac, buf);
674			}
675
676			/*
677			* Parse lines in the configuration string. For each one, split it into
678			* tokens and pass them to "pass0" for processing.
679			*/
680			static int
681			asr_ctx_parse(struct asr_ctx ac, const char str)
682			{
683			size_t len;
684			const char *line;
685			char buf[1024];
686			char *tok[10];
687			int ntok;
688
689			line = str;
690			while (*line) {
691			len = strcspn(line, "\n\0");
692			if (len < sizeof buf) {
693			memmove(buf, line, len);
694			buf[len] = '\0';
695			} else
696			buf[0] = '\0';
697			line += len;
698			if (*line == '\n')
699			line++;
700			buf[strcspn(buf, ";#")] = '\0';
701			if ((ntok = strsplit(buf, tok, 10)) == 0)
702			continue;
703
704			pass0(tok, ntok, ac);
705			}
706
707			return (0);
708			}
709
710			/*
711			* Check for environment variables altering the configuration as described
712			* in resolv.conf(5). Although not documented there, this feature is disabled
713			* for setuid/setgid programs.
714			*/
715			static void
716			asr_ctx_envopts(struct asr_ctx *ac)
717			{
718			char buf[4096], *e;
719			size_t s;
720
721			if (issetugid()) {
722			ac->ac_options \|= RES_NOALIASES;
723			return;
724			}
725
726			if ((e = getenv("RES_OPTIONS")) != NULL) {
727			strlcpy(buf, "options ", sizeof buf);
728			strlcat(buf, e, sizeof buf);
729			s = strlcat(buf, "\n", sizeof buf);
730			if (s < sizeof buf)
731			asr_ctx_parse(ac, buf);
732			}
733
734			if ((e = getenv("LOCALDOMAIN")) != NULL) {
735			strlcpy(buf, "search ", sizeof buf);
736			strlcat(buf, e, sizeof buf);
737			s = strlcat(buf, "\n", sizeof buf);
738			if (s < sizeof buf)
739			asr_ctx_parse(ac, buf);
740			}
741			}
742
743			/*
744			* Parse a resolv.conf(5) nameserver string into a sockaddr.
745			*/
746			static int
747			asr_parse_nameserver(struct sockaddr sa, const char s)
748			{
749			in_port_t portno = 53;
750
751			if (_asr_sockaddr_from_str(sa, PF_UNSPEC, s) == -1)
752			return (-1);
753
754			if (sa->sa_family == PF_INET)
755			((struct sockaddr_in *)sa)->sin_port = htons(portno);
756			else if (sa->sa_family == PF_INET6)
757			((struct sockaddr_in6 *)sa)->sin6_port = htons(portno);
758
759			return (0);
760			}
761
762			/*
763			* Turn a (uncompressed) DNS domain name into a regular nul-terminated string
764			* where labels are separated by dots. The result is put into the "buf" buffer,
765			* truncated if it exceeds "max" chars. The function returns "buf".
766			*/
767			char *
768			_asr_strdname(const char _dname, char buf, size_t max)
769			{
770			const unsigned char *dname = _dname;
771			char *res;
772			size_t left, n, count;
773
774			if (_dname[0] == 0) {
775			strlcpy(buf, ".", max);
776			return buf;
777			}
778
779			res = buf;
780			left = max - 1;
781			for (n = 0; dname[0] && left; n += dname[0]) {
782			count = (dname[0] < (left - 1)) ? dname[0] : (left - 1);
783			memmove(buf, dname + 1, count);
784			dname += dname[0] + 1;
785			left -= count;
786			buf += count;
787			if (left) {
788			left -= 1;
789			*buf++ = '.';
790			}
791			}
792			buf[0] = 0;
793
794			return (res);
795			}
796
797			/*
798			* Read and split the next line from the given namedb file.
799			* Return -1 on error, or put the result in the "tokens" array of
800			* size "ntoken" and returns the number of token on the line.
801			*/
802			int
803			_asr_parse_namedb_line(FILE file, char tokens, int ntoken, char lbuf, size_t sz)
804			{
805			size_t len;
806			char *buf;
807			int ntok;
808
809			again:
810			if ((buf = fgetln(file, &len)) == NULL)
811			return (-1);
812
813			if (len >= sz)
814			goto again;
815
816			if (buf[len - 1] == '\n')
817			len--;
818			else {
819			memcpy(lbuf, buf, len);
820			buf = lbuf;
821			}
822
823			buf[len] = '\0';
824			buf[strcspn(buf, "#")] = '\0';
825			if ((ntok = strsplit(buf, tokens, ntoken)) == 0)
826			goto again;
827
828			return (ntok);
829			}
830
831			/*
832			* Update the async context so that it uses the next configured DB.
833			* Return 0 on success, or -1 if no more DBs is available.
834			*/
835			int
836			_asr_iter_db(struct asr_query *as)
837			{
838			if (as->as_db_idx >= as->as_ctx->ac_dbcount) {
839			DPRINT("asr_iter_db: done\n");
840			return (-1);
841			}
842
843			as->as_db_idx += 1;
844			DPRINT("asr_iter_db: %i\n", as->as_db_idx);
845
846			return (0);
847			}