From 9e277c6c500e3e93cd5e3b091132b5f2f069df2d Mon Sep 17 00:00:00 2001
From: Xiang Xiao <xiaoxiang@xiaomi.com>
Date: Sun, 29 Mar 2020 16:27:56 +0800
Subject: [PATCH] libc/netdb: Return null alias for
 getservbyport_r/getservbyname_r

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: I82728a8ea9a5136e0154cd67ec8de70a4e0ac6ed
---
 libs/libc/netdb/lib_getservbyname.c  |  3 +--
 libs/libc/netdb/lib_getservbynamer.c | 26 ++++----------------------
 libs/libc/netdb/lib_getservbyport.c  |  3 +--
 libs/libc/netdb/lib_getservbyportr.c | 16 +++-------------
 4 files changed, 9 insertions(+), 39 deletions(-)

diff --git a/libs/libc/netdb/lib_getservbyname.c b/libs/libc/netdb/lib_getservbyname.c
index 1bcf78b1a33..697920ddb92 100644
--- a/libs/libc/netdb/lib_getservbyname.c
+++ b/libs/libc/netdb/lib_getservbyname.c
@@ -54,11 +54,10 @@
 FAR struct servent *getservbyname(FAR const char *name, FAR const char *proto)
 {
   static struct servent ent;
-  static char *buf[2];
   struct servent *res;
   int ret;
 
-  ret = getservbyname_r(name, proto, &ent, (void *)buf, sizeof buf, &res);
+  ret = getservbyname_r(name, proto, &ent, NULL, 0, &res);
   return (ret != OK) ? NULL : res;
 }
 
diff --git a/libs/libc/netdb/lib_getservbynamer.c b/libs/libc/netdb/lib_getservbynamer.c
index 56540cd219f..e97f2786de6 100644
--- a/libs/libc/netdb/lib_getservbynamer.c
+++ b/libs/libc/netdb/lib_getservbynamer.c
@@ -78,32 +78,16 @@ int getservbyname_r(FAR const char *name, FAR const char *proto,
                     FAR struct servent *result_buf, FAR char *buf,
                     size_t buflen, FAR struct servent **result)
 {
-  char *end = "";
   int protocol;
   int i;
 
-  DEBUGASSERT(name != NULL && buf != NULL);
+  DEBUGASSERT(name != NULL);
   DEBUGASSERT(result_buf != NULL && result != NULL);
 
   /* Linux man page says result must be NULL in case of failure. */
 
   *result = NULL;
 
-  /* We need space for two pointers for hostalias strings. */
-
-  if (buflen < 2 * sizeof(char *))
-    {
-      return ERANGE;
-    }
-
-  /* Numeric port number strings are not service records. */
-
-  strtoul(name, &end, 10);
-  if (*end == '\0')
-    {
-      return ENOENT;
-    }
-
   if (proto == NULL)
     {
       protocol = 0;
@@ -126,11 +110,9 @@ int getservbyname_r(FAR const char *name, FAR const char *proto,
       if (strcmp(name, g_services_db[i].s_name) == 0 &&
           (protocol == 0 || protocol == g_services_db[i].s_protocol))
         {
-          result_buf->s_name = (char *)name;
-          result_buf->s_aliases = (void *)buf;
-          result_buf->s_aliases[0] = (char *)name;
-          result_buf->s_aliases[1] = NULL;
-          result_buf->s_port = HTONS(g_services_db[i].s_port);
+          result_buf->s_name = (FAR char *)name;
+          result_buf->s_aliases = NULL;
+          result_buf->s_port = htons(g_services_db[i].s_port);
 
           if (g_services_db[i].s_protocol == IPPROTO_TCP)
             {
diff --git a/libs/libc/netdb/lib_getservbyport.c b/libs/libc/netdb/lib_getservbyport.c
index 59c4e4a96e3..b0ecf5ae7d5 100644
--- a/libs/libc/netdb/lib_getservbyport.c
+++ b/libs/libc/netdb/lib_getservbyport.c
@@ -58,11 +58,10 @@
 FAR struct servent *getservbyport(int port, FAR const char *proto)
 {
   static struct servent ent;
-  static FAR char *buf[2];
   struct servent *res;
   int ret;
 
-  ret = getservbyport_r(port, proto, &ent, (FAR void *)buf, sizeof buf, &res);
+  ret = getservbyport_r(port, proto, &ent, NULL, 0, &res);
   return (ret != OK) ? NULL : res;
 }
 
diff --git a/libs/libc/netdb/lib_getservbyportr.c b/libs/libc/netdb/lib_getservbyportr.c
index 233254c9f34..af506ce40e2 100644
--- a/libs/libc/netdb/lib_getservbyportr.c
+++ b/libs/libc/netdb/lib_getservbyportr.c
@@ -70,20 +70,12 @@ int getservbyport_r(int port, FAR const char *proto,
   int protocol;
   int i;
 
-  DEBUGASSERT(buf != NULL);
   DEBUGASSERT(result_buf != NULL && result != NULL);
 
   /* Linux man page says result must be NULL in case of failure. */
 
   *result = NULL;
 
-  /* We need space for two pointers for hostalias strings. */
-
-  if (buflen < 2 * sizeof(char *))
-    {
-      return ERANGE;
-    }
-
   if (proto == NULL)
     {
       protocol = 0;
@@ -106,11 +98,9 @@ int getservbyport_r(int port, FAR const char *proto,
       if (port == g_services_db[i].s_port &&
           (protocol == 0 || protocol == g_services_db[i].s_protocol))
         {
-          result_buf->s_name = (char *)g_services_db[i].s_name;
-          result_buf->s_aliases = (void *)buf;
-          result_buf->s_aliases[0] = (char *)g_services_db[i].s_name;
-          result_buf->s_aliases[1] = NULL;
-          result_buf->s_port = HTONS(g_services_db[i].s_port);
+          result_buf->s_name = (FAR char *)g_services_db[i].s_name;
+          result_buf->s_aliases = NULL;
+          result_buf->s_port = htons(port);
 
           if (g_services_db[i].s_protocol == IPPROTO_TCP)
             {