resolv.conf parsing routines.

lib/lwres/lwconfig.c

+/*
+ * 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);
+}
+