Commit ffbec844 authored by James Brister's avatar James Brister
Browse files

resolv.conf parsing routines.

parent 9094466f
/*
* Copyright (C) 2000 Internet Software Consortium.
*
* 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 INTERNET SOFTWARE CONSORTIUM DISCLAIMS
* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
* CONSORTIUM 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.
*/
/***
*** Module for parsing resolv.conf files.
***
*** entry points are:
*** lwres_conf_init(lwres_conf_t *confdata)
*** intializes data structure for subsequent parsing.
***
*** lwres_conf_parse(lwres_context_t *ctx, const char *filename,
*** lwres_conf_t *confdata)
*** parses a file and fills in the data structure.
***
*** lwres_conf_print(FILE *fp, lwres_conf_t *confdata)
*** prints the data structure to the FILE.
***
*** lwres_conf_clear(lwres_context_t *ctx, lwres_conf_t *confdata)
*** frees up all the internal memory used by the data
*** structure.
***
***/
#include <config.h>
#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <lwres/lwbuffer.h>
#include <lwres/lwres.h>
#include <lwres/result.h>
#include "assert_p.h"
#include "context_p.h"
#if ! defined(NS_INADDRSZ)
#define NS_INADDRSZ 4
#endif
#if ! defined(NS_IN6ADDRSZ)
#define NS_IN6ADDRSZ 16
#endif
extern int lwres_net_pton(int af, const char *src, void *dst);
extern const char *lwres_net_ntop(int af, const void *src, char *dst,
size_t size);
static int lwres_conf_parsenameserver(lwres_context_t *ctx, FILE *fp,
lwres_conf_t *confdata);
static int lwres_conf_parsedomain(lwres_context_t *ctx, FILE *fp,
lwres_conf_t *confdata);
static int lwres_conf_parsesearch(lwres_context_t *ctx, FILE *fp,
lwres_conf_t *confdata);
static int lwres_conf_parsesortlist(lwres_context_t *ctx, FILE *fp,
lwres_conf_t *confdata);
static int lwres_conf_parseoption(lwres_context_t *ctx, FILE *fp,
lwres_conf_t *confdata);
static void lwres_resetaddr(lwres_context_t *ctx, lwres_addr_t *addr,
int freeit);
static int lwres_create_addr(lwres_context_t *ctx, const char *buff,
lwres_addr_t *addr);
/*
* Skip over any leading whitespace and then read in the next sequence of
* non-whitespace characters. Returnss EOF on end-of-file, or the character
* that caused the reading to stop.
*/
static int
getword(FILE *fp, char *buffer, size_t size)
{
int ch;
char *p = buffer;
REQUIRE(buffer != NULL);
REQUIRE(size > 0);
*p = '\0';
ch = fgetc(fp);
while (ch != '\n' && isspace(ch)) {
ch = fgetc(fp);
}
if (ch == EOF) {
return (EOF);
}
do {
*p = '\0';
if (ch == EOF || isspace(ch)) {
break;
} else if ((size_t) (p - buffer) == size - 1) {
return (EOF); /* not enough space */
}
*p++ = (char)ch;
ch = fgetc(fp);
} while (1);
return (ch);
}
static void
lwres_resetaddr(lwres_context_t *ctx, lwres_addr_t *addr, int freeit)
{
REQUIRE(addr != NULL);
if (freeit && addr->address != NULL) {
CTXFREE((void *)addr->address, addr->length);
}
addr->address = NULL;
addr->family = 0;
addr->length = 0;
}
static char *
lwres_strdup(lwres_context_t *ctx, const char *str)
{
char *p;
REQUIRE(*str != NULL);
REQUIRE(strlen(str) > 0);
p = CTXMALLOC(strlen(str) + 1);
if (p != NULL) {
strcpy(p, str);
}
return (p);
}
void
lwres_conf_init(lwres_conf_t *confdata)
{
int i;
REQUIRE(confdata != NULL);
confdata->nsnext = 0;
confdata->domainname = NULL;
confdata->searchnxt = 0;
confdata->sortlistnxt = 0;
confdata->resdebug = 0;
confdata->ndots = 0;
confdata->no_tld_query = 0;
for (i = 0 ; i < LWRES_CONFMAXNAMESERVERS ; i++) {
lwres_resetaddr(NULL, &confdata->nameservers[i], 0);
}
for (i = 0 ; i < LWRES_CONFMAXSEARCH ; i++) {
confdata->search[i] = NULL;
}
for (i = 0 ; i < LWRES_CONFMAXSORTLIST ; i++) {
lwres_resetaddr(NULL, &confdata->sortlist[i].addr, 0);
lwres_resetaddr(NULL, &confdata->sortlist[i].mask, 0);
}
}
void
lwres_conf_clear(lwres_context_t *ctx, lwres_conf_t *confdata)
{
int i;
for (i = 0 ; i < confdata->nsnext ; i++) {
lwres_resetaddr(ctx, &confdata->nameservers[i], 1);
}
if (confdata->domainname != NULL) {
CTXFREE(confdata->domainname,
strlen(confdata->domainname) + 1);
confdata->domainname = NULL;
}
for (i = 0 ; i < confdata->searchnxt ; i++) {
if (confdata->search[i] != NULL) {
CTXFREE(confdata->search[i],
strlen(confdata->search[i]) + 1);
confdata->search[i] = NULL;
}
}
for (i = 0 ; i < LWRES_CONFMAXSORTLIST ; i++) {
lwres_resetaddr(ctx, &confdata->sortlist[i].addr, 1);
lwres_resetaddr(ctx, &confdata->sortlist[i].mask, 1);
}
confdata->nsnext = 0;
confdata->domainname = NULL;
confdata->searchnxt = 0;
confdata->sortlistnxt = 0;
confdata->resdebug = 0;
confdata->ndots = 0;
confdata->no_tld_query = 0;
}
static int
lwres_conf_parsenameserver(lwres_context_t *ctx, FILE *fp,
lwres_conf_t *confdata)
{
char word[LWRES_CONFMAXLINELEN];
int res;
if (confdata->nsnext == LWRES_CONFMAXNAMESERVERS) {
return (LWRES_R_FAILURE);
}
res = getword(fp, word, sizeof(word));
if (strlen(word) == 0) {
return (LWRES_R_FAILURE); /* nothing on line */
} else if (res != EOF && res != '\n') {
return (LWRES_R_FAILURE); /* extra junk on line */
}
res = lwres_create_addr(ctx, word,
&confdata->nameservers[confdata->nsnext++]);
if (res != LWRES_R_SUCCESS) {
return (res);
}
return (LWRES_R_SUCCESS);
}
static int
lwres_conf_parsedomain(lwres_context_t *ctx, FILE *fp, lwres_conf_t *confdata)
{
char word[LWRES_CONFMAXLINELEN];
int res, i;
res = getword(fp, word, sizeof(word));
if (strlen(word) == 0) {
return (LWRES_R_FAILURE); /* nothing else on line */
} else if (res != EOF && res != '\n') {
return (LWRES_R_FAILURE); /* extra junk on line */
}
if (confdata->domainname != NULL) {
CTXFREE(confdata->domainname,
strlen(confdata->domainname) + 1); /* */
}
/* search and domain are mutually exclusive */
for (i = 0 ; i < LWRES_CONFMAXSEARCH ; i++) {
if (confdata->search[i] != NULL) {
CTXFREE(confdata->search[i],
strlen(confdata->search[i])+1);
confdata->search[i] = NULL;
}
}
confdata->searchnxt = 0;
confdata->domainname = lwres_strdup(ctx, word);
if (confdata->domainname == NULL) {
return (LWRES_R_FAILURE);
} else {
return (LWRES_R_SUCCESS);
}
}
static int
lwres_conf_parsesearch(lwres_context_t *ctx, FILE *fp,
lwres_conf_t *confdata)
{
int idx, delim;
char word[LWRES_CONFMAXLINELEN];
if (confdata->domainname != NULL) {
/* search and domain are mutually exclusive */
CTXFREE(confdata->domainname,
strlen(confdata->domainname) + 1);
confdata->domainname = NULL;
}
/* remove any previous search definitions. */
for (idx = 0 ; idx < LWRES_CONFMAXSEARCH ; idx++) {
if (confdata->search[idx] != NULL) {
CTXFREE(confdata->search[idx],
strlen(confdata->search[idx])+1);
confdata->search[idx] = NULL;
}
}
confdata->searchnxt = 0;
delim = getword(fp, word, sizeof(word));
if (strlen(word) == 0) {
return (LWRES_R_FAILURE); /* nothing else on line */
}
idx = 0;
while (strlen(word) > 0) {
if (confdata->searchnxt == LWRES_CONFMAXSEARCH) {
return (LWRES_R_FAILURE); /* too many domains */
}
confdata->search[idx] = lwres_strdup(ctx, word);
if (confdata->search[idx] == NULL) {
return (LWRES_R_FAILURE);
}
if (delim == EOF || delim == '\n') {
break;
} else {
delim = getword(fp, word, sizeof(word));
}
}
return (LWRES_R_SUCCESS);
}
static int
lwres_create_addr(lwres_context_t *ctx, const char *buffer, lwres_addr_t *addr)
{
unsigned char addrbuff[NS_IN6ADDRSZ];
if (lwres_net_pton(AF_INET, buffer, &addrbuff) == 1) {
addr->family = AF_INET;
addr->length = NS_INADDRSZ;
addr->address = CTXMALLOC(NS_INADDRSZ);
#if defined(AF_INET6)
} else if (lwres_net_pton(AF_INET6, buffer, &addrbuff) == 1) {
addr->family = AF_INET6;
addr->length = NS_IN6ADDRSZ;
addr->address = CTXMALLOC(NS_IN6ADDRSZ);
#endif
} else {
return (LWRES_R_FAILURE); /* unrecongnised format */
}
memcpy((void *)addr->address, addrbuff, 4);
return (LWRES_R_SUCCESS);
}
static int
lwres_conf_parsesortlist(lwres_context_t *ctx, FILE *fp,
lwres_conf_t *confdata)
{
int delim, res, idx;
char word[LWRES_CONFMAXLINELEN];
char *p;
delim = getword(fp, word, sizeof(word));
if (strlen(word) == 0) {
return (LWRES_R_FAILURE); /* empty line after keyword */
}
while (strlen(word) > 0) {
if (confdata->sortlistnxt == LWRES_CONFMAXSORTLIST) {
return (LWRES_R_FAILURE); /* too many values. */
}
p = strchr(word, '/');
if (p != NULL) {
*p++ = '\0';
}
idx = confdata->sortlistnxt;
res = lwres_create_addr(ctx, word,
&confdata->sortlist[idx].addr);
if (res != LWRES_R_SUCCESS) {
return (res);
}
if (p != NULL) {
res = lwres_create_addr(ctx, p,
&confdata->sortlist[idx].mask);
if (res != LWRES_R_SUCCESS) {
return (res);
}
}
confdata->sortlistnxt++;
if (delim == EOF || delim == '\n') {
break;
} else {
delim = getword(fp, word, sizeof(word));
}
}
return (LWRES_R_SUCCESS);
}
static int
lwres_conf_parseoption(lwres_context_t *ctx, FILE *fp,
lwres_conf_t *confdata)
{
int delim;
long ndots;
char *p;
char word[LWRES_CONFMAXLINELEN];
(void) ctx;
REQUIRE(confdata != NULL);
delim = getword(fp, word, sizeof(word));
if (strlen(word) == 0) {
return (LWRES_R_FAILURE); /* empty line after keyword */
}
while (strlen(word) > 0) {
if (strcmp("debug", word) == 0) {
confdata->resdebug = 1;
} else if (strcmp("no_tld_query", word) == 0) {
confdata->no_tld_query = 1;
} else if (strncmp("ndots:", word, 6) == 0) {
ndots = strtol(word + 6, &p, 10);
if (*p != '\0') { /* bad string */
return (LWRES_R_FAILURE);
}
confdata->ndots = ndots;
}
if (delim == EOF || delim == '\n') {
break;
} else {
delim = getword(fp, word, sizeof(word));
}
}
return (LWRES_R_SUCCESS);
}
int
lwres_conf_parse(lwres_context_t *ctx, const char *filename,
lwres_conf_t *confdata)
{
FILE *fp = NULL;
char word[256];
int rval, delim;
REQUIRE(filename != NULL);
REQUIRE(strlen(filename) > 0);
REQUIRE(confdata != NULL);
errno = 0;
if ((fp = fopen(filename, "r")) == NULL)
return (LWRES_R_FAILURE);
do {
delim = getword(fp, word, sizeof(word));
if (strlen(word) == 0) {
rval = LWRES_R_SUCCESS;
break;
}
if (strcmp(word, "nameserver") == 0) {
rval = lwres_conf_parsenameserver(ctx, fp, confdata);
} else if (strcmp(word, "domain") == 0) {
rval = lwres_conf_parsedomain(ctx, fp, confdata);
} else if (strcmp(word, "search") == 0) {
rval = lwres_conf_parsesearch(ctx, fp, confdata);
} else if (strcmp(word, "sortlist") == 0) {
rval = lwres_conf_parsesortlist(ctx, fp, confdata);
} else if (strcmp(word, "option") == 0) {
rval = lwres_conf_parseoption(ctx, fp, confdata);
}
} while (rval == LWRES_R_SUCCESS);
fclose(fp);
return (rval);
}
int
lwres_conf_print(FILE *fp, lwres_conf_t *confdata)
{
int i;
char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"];
const char *p;
REQUIRE(confdata->nsnext <= LWRES_CONFMAXNAMESERVERS);
for (i = 0 ; i < confdata->nsnext ; i++) {
p = lwres_net_ntop(confdata->nameservers[i].family,
confdata->nameservers[i].address,
tmp, sizeof(tmp));
if (p != tmp) {
return (LWRES_R_FAILURE);
}
fprintf(fp, "nameserver %s\n", tmp);
}
if (confdata->domainname != NULL) {
fprintf(fp, "domain %s\n", confdata->domainname);
} else if (confdata->searchnxt > 0) {
REQUIRE(confdata->searchnxt <= LWRES_CONFMAXSEARCH);
fprintf(fp, "search");
for (i = 0 ; i < confdata->searchnxt ; i++) {
fputs(confdata->search[i], fp);
}
fputc('\n', fp);
}
REQUIRE(confdata->sortlistnxt <= LWRES_CONFMAXSORTLIST);
if (confdata->sortlistnxt > 0) {
fputs("sortlist", fp);
for (i = 0 ; i < confdata->sortlistnxt ; i++) {
p = lwres_net_ntop(confdata->sortlist[i].addr.family,
confdata->sortlist[i].addr.address,
tmp, sizeof(tmp));
if (p != tmp) {
return (LWRES_R_FAILURE);
}
fprintf(fp, " %s", tmp);
if (confdata->sortlist[i].mask.length > 0) {
p = lwres_net_ntop
(confdata->sortlist[i].mask.family,
confdata->sortlist[i].mask.address,
tmp, sizeof(tmp));
if (p != tmp) {
return (LWRES_R_FAILURE);
}
fprintf(fp, "/%s", tmp);
}
}
fputc('\n', fp);
}
if (confdata->resdebug) {
fprintf(fp, "options debug\n");
}
if (confdata->ndots > 0) {
fprintf(fp, "options ndots:%d\n", confdata->ndots);
}
if (confdata->no_tld_query) {
fprintf(fp, "options no_tld_query\n");
}
return (LWRES_R_SUCCESS);
}
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