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-rw-r--r--src/network/lookup_name.c42
1 files changed, 41 insertions, 1 deletions
diff --git a/src/network/lookup_name.c b/src/network/lookup_name.c
index fb7b5c12..09734b50 100644
--- a/src/network/lookup_name.c
+++ b/src/network/lookup_name.c
@@ -157,6 +157,46 @@ static int name_from_dns(struct address buf[static MAXADDRS], char canon[static
 	return EAI_FAIL;
 }
 
+static int name_from_dns_search(struct address buf[static MAXADDRS], char canon[static 256], const char *name, int family)
+{
+	char search[256];
+	struct resolvconf conf;
+	size_t l, dots;
+	char *p, *z;
+
+	if (__get_resolv_conf(&conf, search, sizeof search) < 0) return -1;
+
+	/* Count dots, suppress search when >=ndots or name ends in
+	 * a dot, which is an explicit request for global scope. */
+	for (dots=l=0; name[l]; l++) if (name[l]=='.') dots++;
+	if (dots >= conf.ndots || name[l-1]=='.') *search = 0;
+
+	/* This can never happen; the caller already checked length. */
+	if (l >= 256) return EAI_NONAME;
+
+	/* Name with search domain appended is setup in canon[]. This both
+	 * provides the desired default canonical name (if the requested
+	 * name is not a CNAME record) and serves as a buffer for passing
+	 * the full requested name to name_from_dns. */
+	memcpy(canon, name, l);
+	canon[l] = '.';
+
+	for (p=search; *p; p=z) {
+		for (; isspace(*p); p++);
+		for (z=p; *z && !isspace(*z); z++);
+		if (z==p) break;
+		if (z-p < 256 - l - 1) {
+			memcpy(canon+l+1, p, z-p);
+			canon[z-p+1+l] = 0;
+			int cnt = name_from_dns(buf, canon, canon, family);
+			if (cnt) return cnt;
+		}
+	}
+
+	canon[l] = 0;
+	return name_from_dns(buf, canon, name, family);
+}
+
 static const struct policy {
 	unsigned char addr[16];
 	unsigned char len, mask;
@@ -257,7 +297,7 @@ int __lookup_name(struct address buf[static MAXADDRS], char canon[static 256], c
 	if (!cnt) cnt = name_from_numeric(buf, name, family);
 	if (!cnt && !(flags & AI_NUMERICHOST)) {
 		cnt = name_from_hosts(buf, canon, name, family);
-		if (!cnt) cnt = name_from_dns(buf, canon, name, family);
+		if (!cnt) cnt = name_from_dns_search(buf, canon, name, family);
 	}
 	if (cnt<=0) return cnt ? cnt : EAI_NONAME;