From f7455baa01805f2f0904de8cfe51362dc220be49 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Fri, 18 Dec 2015 14:16:03 +0100
Subject: shared: add dns_name_parent() call to determine parent domain of a
 domain

---
 src/shared/dns-domain.c | 16 +++++++++++-----
 src/shared/dns-domain.h |  4 ++++
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/src/shared/dns-domain.c b/src/shared/dns-domain.c
index 0466857042..c46f7d21b7 100644
--- a/src/shared/dns-domain.c
+++ b/src/shared/dns-domain.c
@@ -48,7 +48,6 @@ int dns_label_unescape(const char **name, char *dest, size_t sz) {
 
         assert(name);
         assert(*name);
-        assert(dest);
 
         n = *name;
         d = dest;
@@ -79,9 +78,12 @@ int dns_label_unescape(const char **name, char *dest, size_t sz) {
 
                         else if (*n == '\\' || *n == '.') {
                                 /* Escaped backslash or dot */
-                                *(d++) = *(n++);
+
+                                if (d)
+                                        *(d++) = *n;
                                 sz--;
                                 r++;
+                                n++;
 
                         } else if (n[0] >= '0' && n[0] <= '9') {
                                 unsigned k;
@@ -100,7 +102,8 @@ int dns_label_unescape(const char **name, char *dest, size_t sz) {
                                 if (k < ' ' || k > 255 || k == 127)
                                         return -EINVAL;
 
-                                *(d++) = (char) k;
+                                if (d)
+                                        *(d++) = (char) k;
                                 sz--;
                                 r++;
 
@@ -111,9 +114,12 @@ int dns_label_unescape(const char **name, char *dest, size_t sz) {
                 } else if ((uint8_t) *n >= (uint8_t) ' ' && *n != 127) {
 
                         /* Normal character */
-                        *(d++) = *(n++);
+
+                        if (d)
+                                *(d++) = *n;
                         sz--;
                         r++;
+                        n++;
                 } else
                         return -EINVAL;
         }
@@ -122,7 +128,7 @@ int dns_label_unescape(const char **name, char *dest, size_t sz) {
         if (r == 0 && *n)
                 return -EINVAL;
 
-        if (sz >= 1)
+        if (sz >= 1 && d)
                 *d = 0;
 
         *name = n;
diff --git a/src/shared/dns-domain.h b/src/shared/dns-domain.h
index 3f8f621802..02b51832b6 100644
--- a/src/shared/dns-domain.h
+++ b/src/shared/dns-domain.h
@@ -47,6 +47,10 @@ int dns_label_unescape_suffix(const char *name, const char **label_end, char *de
 int dns_label_escape(const char *p, size_t l, char *dest, size_t sz);
 int dns_label_escape_new(const char *p, size_t l, char **ret);
 
+static inline int dns_name_parent(const char **name) {
+        return dns_label_unescape(name, NULL, DNS_LABEL_MAX);
+}
+
 int dns_label_apply_idna(const char *encoded, size_t encoded_size, char *decoded, size_t decoded_max);
 int dns_label_undo_idna(const char *encoded, size_t encoded_size, char *decoded, size_t decoded_max);
 
-- 
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