From ca392ac658005ed4fb3529806ad69a00f1c0984c Mon Sep 17 00:00:00 2001
From: Maciej Urbanski <rooter@kyberian.net>
Date: Mon, 12 Feb 2018 01:08:54 +0100
Subject: [PATCH] allow empty DOCKER_DOMAIN_SUFFIX

---
 m4/arg_with_define_string.m4 |  2 +-
 src/libnss_docker.c          | 28 +++++++++++++++-------------
 2 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/m4/arg_with_define_string.m4 b/m4/arg_with_define_string.m4
index 8a302f3..3e81de8 100644
--- a/m4/arg_with_define_string.m4
+++ b/m4/arg_with_define_string.m4
@@ -12,7 +12,7 @@
 AC_DEFUN([ACX_ARG_WITH_DEFINE_STRING], [
     AC_MSG_CHECKING([$2])
     AC_ARG_WITH([$1], [AS_HELP_STRING([--with-$1=$3], [$2])])
-    AS_VAR_IF(AS_TR_SH([with_$1]), [], [
+    AS_VAR_SET_IF(AS_TR_SH([with_$1]), [], [
         AC_CACHE_VAL(AS_TR_SH([acx_cv_arg_with_$1]), [
             AS_VAR_SET(AS_TR_SH([acx_cv_arg_with_$1]), [$3])])
         AS_VAR_COPY(AS_TR_SH([with_$1]), AS_TR_SH([acx_cv_arg_with_$1]))])
diff --git a/src/libnss_docker.c b/src/libnss_docker.c
index 5902005..739fd46 100644
--- a/src/libnss_docker.c
+++ b/src/libnss_docker.c
@@ -76,9 +76,6 @@ enum nss_status _nss_docker_gethostbyname3_r(
     /* hostname is name without domain suffix */
     char hostname[256];
 
-    /* docker domain suffix starts here */
-    char *hostname_suffix_ptr;
-
     /* address of Docker API server */
     struct sockaddr_un docker_api_addr;
 
@@ -162,18 +159,23 @@ enum nss_status _nss_docker_gethostbyname3_r(
     strncpy(hostname, name, sizeof(hostname));
     hostname[name_len] = '\0';
 
-    /* Handle only .docker domain */
-    if ((hostname_suffix_ptr = strstr(hostname, DOCKER_DOMAIN_SUFFIX)) == NULL) {
-        *errnop = EADDRNOTAVAIL;
-        goto return_unavail;
-    }
+    /* Handle only domains ending with DOCKER_DOMAIN_SUFFIX */
+    if (sizeof(DOCKER_DOMAIN_SUFFIX)) {
+        /* docker domain suffix starts here */
+        char *hostname_suffix_ptr = strstr(hostname, DOCKER_DOMAIN_SUFFIX);
 
-    if (hostname_suffix_ptr[sizeof(DOCKER_DOMAIN_SUFFIX) - 1] != '\0') {
-        *errnop = EADDRNOTAVAIL;
-        goto return_unavail;
-    }
+        if (hostname_suffix_ptr == NULL) {
+            *errnop = EADDRNOTAVAIL;
+            goto return_unavail;
+        }
 
-    *hostname_suffix_ptr = '\0';
+        if (hostname_suffix_ptr[sizeof(DOCKER_DOMAIN_SUFFIX) - 1] != '\0') {
+            *errnop = EADDRNOTAVAIL;
+            goto return_unavail;
+        }
+
+        *hostname_suffix_ptr = '\0';
+    }
 
     /* Connect to Docker API socket */
     memset((char *) &docker_api_addr, 0, sizeof(docker_api_addr));