fix: populate ldns submodule and add autotools to LDNS build stage

- Re-cloned zonemaster-ldns with --recurse-submodules so the bundled
  ldns C library source (including Changelog and configure.ac) is present
- Added autoconf, automake, libtool to Dockerfile.backend ldns-build stage
  so libtoolize + autoreconf can generate ldns/configure during make

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

zonemaster-ldns/ldns/masterdont/config_file.c

@@ -0,0 +1,210 @@
+/* config_file.c - masterdont config file reading */
+#include "config.h"
+#include "config_file.h"
+#include "zones.h"
+#include "zinfo.h"
+
+/* used during config file reading */
+static struct config_read cread;
+
+/* config syntax error */
+static void config_err(char* str)
+{
+	if(cread.include_depth == 0) 
+		fprintf(stderr, "error: %s\n", str);
+	else fprintf(stderr, "error in %s %d: %s\n", 
+		cread.fnames[cread.include_depth-1],
+		cread.lineno[cread.include_depth-1], str);
+	exit(1);
+}
+
+/* skip to end of line */
+static void skip_to_eol(FILE* in)
+{
+	int c;
+	while( (c=fgetc(in)) != EOF) {
+		if(c == '\n') {
+			cread.lineno[cread.include_depth-1]++;
+			return;
+		}
+	}
+	/* EOF is end of line too for ending a comment */
+}
+
+/* fill quoted string, remove ending quote */
+static void fillup_quoted(FILE* in, char* buf, size_t sz, char q)
+{
+	size_t pos = strlen(buf);
+	int c;
+	if(pos>0 && buf[pos-1] == q) {
+		buf[pos-1] = 0;
+		return;
+	}
+	while( (c=fgetc(in)) != EOF ) {
+		if(c == q) {
+			buf[pos] = 0;
+			return;
+		}
+		buf[pos++] = c;
+		if(pos >= sz) config_err("string too long");
+	}
+	config_err("no ending quote for string");
+}
+
+/* skip whitespace */
+static char skip_white(FILE* in)
+{
+	int c;
+	while( (c=fgetc(in)) != EOF ) {
+		if(c == ' ' || c == '\t' || c == '\r')
+			continue;
+		else if(c == '\n') {
+			cread.lineno[cread.include_depth-1]++;
+			continue;
+		}
+		return c;
+	}
+	return 0;
+}
+
+/* mini lexer and parser; grab one word from the input file, skip
+ * whitespace and comments. return 0 on EOF */
+static char* read_token(FILE* in)
+{
+	static char buf[10240];
+	buf[sizeof(buf)-1] = 0;
+	while(!feof(in)) {
+		buf[0] = skip_white(in);
+		if(feof(in)) return 0;
+		if(fscanf(in, "%10230s", buf+1) != 1) {
+			return 0;
+		}
+		if(buf[0] == '#') {
+			skip_to_eol(in);
+			continue;
+		} else if(buf[0] == '\"' || buf[0] == '\'') {
+			fillup_quoted(in, buf, sizeof(buf), buf[0]);
+			return buf+1;
+		}
+		return buf;
+	}
+	return 0;
+}
+
+struct config_file* config_file_create()
+{
+	struct config_file* cfg = (struct config_file*)calloc(1, sizeof(*cfg));
+	if(!cfg) {
+		printf("out of memory\n");
+		exit(1);
+	}
+	cfg->port = DEFAULT_PORT;
+	return cfg;
+}
+
+void config_file_delete(struct config_file* cfg)
+{
+	if(!cfg) return;
+	free(cfg);
+}
+
+/* open new include file */
+static void config_open_include(const char* fname)
+{
+	if(cread.include_depth >= MAX_INCLUDES)
+		config_err("too many include files");
+	cread.fnames[cread.include_depth] = strdup(fname);
+	if(!cread.fnames[cread.include_depth])
+		config_err("out of memory");
+	cread.fstack[cread.include_depth] = fopen(fname, "ra");
+	if(!cread.fstack[cread.include_depth]) {
+		perror(fname);
+		config_err("could not open config file");
+	}
+	cread.lineno[cread.include_depth] = 1;
+	cread.include_depth ++;
+}
+
+/* close include file */
+static void config_close_include(void)
+{
+	if(cread.include_depth == 0) config_err("unexpected end of file");
+	free(cread.fnames[cread.include_depth-1]);
+	fclose(cread.fstack[cread.include_depth-1]);
+	cread.fstack[cread.include_depth-1] = NULL;
+	cread.include_depth--;
+}
+
+void config_file_read(struct config_file* cfg, const char* fname, 
+	struct zones_t* zones)
+{
+	char* p;
+	char key[1024];
+	cread.cfg = cfg;
+	cread.zones = zones;
+	cread.include_depth = 0;
+	cread.zone_read = 0;
+
+	config_open_include(fname);
+	while(cread.include_depth > 0) {
+		p = read_token(cread.fstack[cread.include_depth-1]);
+		if(p == 0) {
+			config_close_include();
+			continue;
+		}
+		if(strcmp(p, "server:") == 0)
+			continue;
+		else if(strcmp(p, "zone:") == 0) {
+			if(cread.zone_read) config_file_add_zone(&cread);
+			cread.zone_read = 1;
+			cread.zone_linenr = cread.lineno[cread.include_depth-1];
+			cread.zone_name = NULL;
+			cread.zone_dir = NULL;
+			continue;
+		}
+		key[sizeof(key)-1]=0;
+		strncpy(key, p, sizeof(key)-1);
+		while((p=read_token(cread.fstack[cread.include_depth-1]))==0){
+			config_close_include();
+			if(cread.include_depth == 0) 
+				config_err("unexpected end of file");
+		}
+		
+		if(strcmp(key, "include:") == 0) {
+			config_open_include(p);
+		} else if(strcmp(key, "port:") == 0) {
+			cfg->port = atoi(p);
+			if(cfg->port == 0) config_err("invalid port number");
+		} else if(strcmp(key, "name:") == 0) {
+			free(cread.zone_name);
+			cread.zone_name = strdup(p);
+			if(!cread.zone_name) config_err("out of memory");
+		} else if(strcmp(key, "dir:") == 0) {
+			free(cread.zone_dir);
+			cread.zone_dir = strdup(p);
+			if(!cread.zone_dir) config_err("out of memory");
+		}
+	}
+	if(cread.zone_read) config_file_add_zone(&cread);
+}
+
+void config_file_add_zone(struct config_read* cr)
+{
+	struct zone_entry_t* entry;
+	if(cr->zone_name == NULL) {
+		fprintf(stderr, "in zone declared on line %d\n", 
+			cr->zone_linenr);
+		config_err("zone has no name");
+	}
+	if(cr->zone_dir == NULL) {
+		fprintf(stderr, "in zone declared on line %d\n", 
+			cr->zone_linenr);
+		config_err("zone has no dir");
+	}
+	entry = zones_insert(cr->zones, cr->zone_name, LDNS_RR_CLASS_IN);
+	if(!entry) {
+		config_err("out of memory adding zone");
+	}
+	entry->zinfo->dir = cr->zone_dir;
+	free(cr->zone_name);
+}