gaih_inet: make numeric lookup a separate routine

Introduce the gaih_result structure and general paradigm for cleanups
that follow to process the lookup request and return a result.  A lookup
function (like text_to_binary_address), should return an integer error
code and set members of gaih_result based on what it finds.  If the
function does not have a result and no errors have occurred during the
lookup, it should return 0 and res.at should be set to NULL, allowing a
subsequent function to do the lookup until we run out of options.

Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: DJ Delorie <dj@redhat.com>
(cherry picked from commit 26dea46119)

sysdeps/posix/getaddrinfo.c

@@ -116,6 +116,12 @@ struct gaih_typeproto
     char name[8];
   };
 
+struct gaih_result
+{
+  struct gaih_addrtuple *at;
+  char *canon;
+};
+
 /* Values for `protoflag'.  */
 #define GAI_PROTO_NOSERVICE	1
 #define GAI_PROTO_PROTOANY	2
@@ -297,7 +303,7 @@ convert_hostent_to_gaih_addrtuple (const struct addrinfo *req,
 	}								      \
       *pat = addrmem;							      \
 									      \
-      if (localcanon != NULL && canon == NULL)				      \
+      if (localcanon != NULL && res.canon == NULL)			      \
 	{								      \
 	  char *canonbuf = __strdup (localcanon);			      \
 	  if (canonbuf == NULL)						      \
@@ -306,7 +312,7 @@ convert_hostent_to_gaih_addrtuple (const struct addrinfo *req,
 	      result = -EAI_SYSTEM;					      \
 	      goto free_and_return;					      \
 	    }								      \
-	  canon = canonbuf;						      \
+	  res.canon = canonbuf;						      \
 	}								      \
       if (_family == AF_INET6 && *pat != NULL)				      \
 	got_ipv6 = true;						      \
@@ -342,9 +348,9 @@ getcanonname (nss_action_list nip, struct gaih_addrtuple *at, const char *name)
 
 static int
 process_canonname (const struct addrinfo *req, const char *orig_name,
-		   char **canonp)
+		   struct gaih_result *res)
 {
-  char *canon = *canonp;
+  char *canon = res->canon;
 
   if ((req->ai_flags & AI_CANONNAME) != 0)
     {
@@ -368,7 +374,7 @@ process_canonname (const struct addrinfo *req, const char *orig_name,
 	return -EAI_MEMORY;
     }
 
-  *canonp = canon;
+  res->canon = canon;
   return 0;
 }
 
@@ -460,6 +466,105 @@ get_servtuples (const struct gaih_service *service, const struct addrinfo *req,
   return 0;
 }
 
+/* Convert numeric addresses to binary into RES.  On failure, RES->AT is set to
+   NULL and an error code is returned.  If AI_NUMERIC_HOST is not requested and
+   the function cannot determine a result, RES->AT is set to NULL and 0
+   returned.  */
+
+static int
+text_to_binary_address (const char *name, const struct addrinfo *req,
+			struct gaih_result *res)
+{
+  struct gaih_addrtuple *at = res->at;
+  int result = 0;
+
+  assert (at != NULL);
+
+  memset (at->addr, 0, sizeof (at->addr));
+  if (__inet_aton_exact (name, (struct in_addr *) at->addr) != 0)
+    {
+      if (req->ai_family == AF_UNSPEC || req->ai_family == AF_INET)
+	at->family = AF_INET;
+      else if (req->ai_family == AF_INET6 && (req->ai_flags & AI_V4MAPPED))
+	{
+	  at->addr[3] = at->addr[0];
+	  at->addr[2] = htonl (0xffff);
+	  at->addr[1] = 0;
+	  at->addr[0] = 0;
+	  at->family = AF_INET6;
+	}
+      else
+	{
+	  result = -EAI_ADDRFAMILY;
+	  goto out;
+	}
+
+      if (req->ai_flags & AI_CANONNAME)
+	{
+	  char *canonbuf = __strdup (name);
+	  if (canonbuf == NULL)
+	    {
+	      result = -EAI_MEMORY;
+	      goto out;
+	    }
+	  res->canon = canonbuf;
+	}
+      return 0;
+    }
+
+  char *scope_delim = strchr (name, SCOPE_DELIMITER);
+  int e;
+
+  if (scope_delim == NULL)
+    e = inet_pton (AF_INET6, name, at->addr);
+  else
+    e = __inet_pton_length (AF_INET6, name, scope_delim - name, at->addr);
+
+  if (e > 0)
+    {
+      if (req->ai_family == AF_UNSPEC || req->ai_family == AF_INET6)
+	at->family = AF_INET6;
+      else if (req->ai_family == AF_INET
+	       && IN6_IS_ADDR_V4MAPPED (at->addr))
+	{
+	  at->addr[0] = at->addr[3];
+	  at->family = AF_INET;
+	}
+      else
+	{
+	  result = -EAI_ADDRFAMILY;
+	  goto out;
+	}
+
+      if (scope_delim != NULL
+	  && __inet6_scopeid_pton ((struct in6_addr *) at->addr,
+				   scope_delim + 1, &at->scopeid) != 0)
+	{
+	  result = -EAI_NONAME;
+	  goto out;
+	}
+
+      if (req->ai_flags & AI_CANONNAME)
+	{
+	  char *canonbuf = __strdup (name);
+	  if (canonbuf == NULL)
+	    {
+	      result = -EAI_MEMORY;
+	      goto out;
+	    }
+	  res->canon = canonbuf;
+	}
+      return 0;
+    }
+
+  if ((req->ai_flags & AI_NUMERICHOST))
+    result = -EAI_NONAME;
+
+out:
+  res->at = NULL;
+  return result;
+}
+
 static int
 gaih_inet (const char *name, const struct gaih_service *service,
 	   const struct addrinfo *req, struct addrinfo **pai,
@@ -468,9 +573,7 @@ gaih_inet (const char *name, const struct gaih_service *service,
   struct gaih_servtuple st[sizeof (gaih_inet_typeproto)
 			   / sizeof (struct gaih_typeproto)] = {0};
 
-  struct gaih_addrtuple *at = NULL;
   bool got_ipv6 = false;
-  char *canon = NULL;
   const char *orig_name = name;
 
   /* Reserve stack memory for the scratch buffer in the getaddrinfo
@@ -485,6 +588,7 @@ gaih_inet (const char *name, const struct gaih_service *service,
   struct gaih_addrtuple *addrmem = NULL;
   int result = 0;
 
+  struct gaih_result res = {0};
   if (name != NULL)
     {
       if (req->ai_flags & AI_IDN)
@@ -497,106 +601,15 @@ gaih_inet (const char *name, const struct gaih_service *service,
 	  malloc_name = true;
 	}
 
-      uint32_t addr[4];
+      res.at = alloca_account (sizeof (struct gaih_addrtuple), alloca_used);
-      if (__inet_aton_exact (name, (struct in_addr *) addr) != 0)
+      res.at->scopeid = 0;
-	{
+      res.at->next = NULL;
-	  at = alloca_account (sizeof (struct gaih_addrtuple), alloca_used);
-	  at->scopeid = 0;
-	  at->next = NULL;
 
-	  if (req->ai_family == AF_UNSPEC || req->ai_family == AF_INET)
+      if ((result = text_to_binary_address (name, req, &res)) != 0)
-	    {
-	      memcpy (at->addr, addr, sizeof (at->addr));
-	      at->family = AF_INET;
-	    }
-	  else if (req->ai_family == AF_INET6 && (req->ai_flags & AI_V4MAPPED))
-	    {
-	      at->addr[3] = addr[0];
-	      at->addr[2] = htonl (0xffff);
-	      at->addr[1] = 0;
-	      at->addr[0] = 0;
-	      at->family = AF_INET6;
-	    }
-	  else
-	    {
-	      result = -EAI_ADDRFAMILY;
 	goto free_and_return;
-	    }
+      else if (res.at != NULL)
-
-	  if (req->ai_flags & AI_CANONNAME)
-	    {
-	      char *canonbuf = __strdup (name);
-	      if (canonbuf == NULL)
-		{
-		  result = -EAI_MEMORY;
-		  goto free_and_return;
-		}
-	      canon = canonbuf;
-	    }
-
 	goto process_list;
-	}
 
-      char *scope_delim = strchr (name, SCOPE_DELIMITER);
-      int e;
-
-      if (scope_delim == NULL)
-	e = inet_pton (AF_INET6, name, addr);
-      else
-	e = __inet_pton_length (AF_INET6, name, scope_delim - name, addr);
-
-      if (e > 0)
-	{
-	  at = alloca_account (sizeof (struct gaih_addrtuple),
-			       alloca_used);
-	  at->scopeid = 0;
-	  at->next = NULL;
-
-	  if (req->ai_family == AF_UNSPEC || req->ai_family == AF_INET6)
-	    {
-	      memcpy (at->addr, addr, sizeof (at->addr));
-	      at->family = AF_INET6;
-	    }
-	  else if (req->ai_family == AF_INET
-		   && IN6_IS_ADDR_V4MAPPED (addr))
-	    {
-	      at->addr[0] = addr[3];
-	      at->addr[1] = addr[1];
-	      at->addr[2] = addr[2];
-	      at->addr[3] = addr[3];
-	      at->family = AF_INET;
-	    }
-	  else
-	    {
-	      result = -EAI_ADDRFAMILY;
-	      goto free_and_return;
-	    }
-
-	  if (scope_delim != NULL
-	      && __inet6_scopeid_pton ((struct in6_addr *) at->addr,
-				       scope_delim + 1,
-				       &at->scopeid) != 0)
-	    {
-	      result = -EAI_NONAME;
-	      goto free_and_return;
-	    }
-
-	  if (req->ai_flags & AI_CANONNAME)
-	    {
-	      char *canonbuf = __strdup (name);
-	      if (canonbuf == NULL)
-		{
-		  result = -EAI_MEMORY;
-		  goto free_and_return;
-		}
-	      canon = canonbuf;
-	    }
-
-	  goto process_list;
-	}
-
-      if ((req->ai_flags & AI_NUMERICHOST) == 0)
-	{
       int no_data = 0;
       int no_inet6_data = 0;
       nss_action_list nip;
@@ -641,7 +654,7 @@ gaih_inet (const char *name, const struct gaih_service *service,
 		      result = -EAI_MEMORY;
 		      goto free_and_return;
 		    }
-		      at = addrmem;
+		  res.at = addrmem;
 		}
 	      else
 		{
@@ -694,7 +707,7 @@ gaih_inet (const char *name, const struct gaih_service *service,
 		}
 
 	      struct gaih_addrtuple *addrfree = addrmem;
-		  struct gaih_addrtuple **pat = &at;
+	      struct gaih_addrtuple **pat = &res.at;
 
 	      for (int i = 0; i < air->naddrs; ++i)
 		{
@@ -721,7 +734,7 @@ gaih_inet (const char *name, const struct gaih_service *service,
 		  (*pat)->next = NULL;
 		  if (added_canon || air->canon == NULL)
 		    (*pat)->name = NULL;
-		      else if (canon == NULL)
+		  else if (res.canon == NULL)
 		    {
 		      char *canonbuf = __strdup (air->canon);
 		      if (canonbuf == NULL)
@@ -729,7 +742,7 @@ gaih_inet (const char *name, const struct gaih_service *service,
 			  result = -EAI_MEMORY;
 			  goto free_and_return;
 			}
-			  canon = (*pat)->name = canonbuf;
+		      res.canon = (*pat)->name = canonbuf;
 		    }
 
 		  if (air->family[i] == AF_INET
@@ -792,10 +805,10 @@ gaih_inet (const char *name, const struct gaih_service *service,
 	{
 	  /* Always start afresh; continue should discard previous results
 	     and the hosts database does not support merge.  */
-	      at = NULL;
+	  res.at = NULL;
-	      free (canon);
+	  free (res.canon);
 	  free (addrmem);
-	      canon = NULL;
+	  res.canon = NULL;
 	  addrmem = NULL;
 	  got_ipv6 = false;
 
@@ -818,14 +831,14 @@ gaih_inet (const char *name, const struct gaih_service *service,
 	    {
 	      while (1)
 		{
-		      status = DL_CALL_FCT (fct4, (name, &at,
+		  status = DL_CALL_FCT (fct4, (name, &res.at,
 					       tmpbuf->data, tmpbuf->length,
 					       &errno, &h_errno,
 					       NULL));
 		  if (status == NSS_STATUS_SUCCESS)
 		    break;
 		  /* gethostbyname4_r may write into AT, so reset it.  */
-		      at = NULL;
+		  res.at = NULL;
 		  if (status != NSS_STATUS_TRYAGAIN
 		      || errno != ERANGE || h_errno != NETDB_INTERNAL)
 		    {
@@ -849,19 +862,19 @@ gaih_inet (const char *name, const struct gaih_service *service,
 		  assert (!no_data);
 		  no_data = 1;
 
-		      if ((req->ai_flags & AI_CANONNAME) != 0 && canon == NULL)
+		  if ((req->ai_flags & AI_CANONNAME) != 0 && res.canon == NULL)
 		    {
-			  char *canonbuf = __strdup (at->name);
+		      char *canonbuf = __strdup (res.at->name);
 		      if (canonbuf == NULL)
 			{
 			  __resolv_context_put (res_ctx);
 			  result = -EAI_MEMORY;
 			  goto free_and_return;
 			}
-			  canon = canonbuf;
+		      res.canon = canonbuf;
 		    }
 
-		      struct gaih_addrtuple **pat = &at;
+		  struct gaih_addrtuple **pat = &res.at;
 
 		  while (*pat != NULL)
 		    {
@@ -913,7 +926,7 @@ gaih_inet (const char *name, const struct gaih_service *service,
 
 	      if (fct != NULL)
 		{
-		      struct gaih_addrtuple **pat = &at;
+		  struct gaih_addrtuple **pat = &res.at;
 
 		  if (req->ai_family == AF_INET6
 		      || req->ai_family == AF_UNSPEC)
@@ -945,16 +958,16 @@ gaih_inet (const char *name, const struct gaih_service *service,
 		      || status == NSS_STATUS_SUCCESS)
 		    {
 		      if ((req->ai_flags & AI_CANONNAME) != 0
-			      && canon == NULL)
+			  && res.canon == NULL)
 			{
-			      char *canonbuf = getcanonname (nip, at, name);
+			  char *canonbuf = getcanonname (nip, res.at, name);
 			  if (canonbuf == NULL)
 			    {
 			      __resolv_context_put (res_ctx);
 			      result = -EAI_MEMORY;
 			      goto free_and_return;
 			    }
-			      canon = canonbuf;
+			  res.canon = canonbuf;
 			}
 		      status = NSS_STATUS_SUCCESS;
 		    }
@@ -1020,10 +1033,9 @@ gaih_inet (const char *name, const struct gaih_service *service,
 
 	  goto free_and_return;
 	}
-	}
 
     process_list:
-      if (at == NULL)
+      if (res.at == NULL)
 	{
 	  result = -EAI_NONAME;
 	  goto free_and_return;
@@ -1032,21 +1044,22 @@ gaih_inet (const char *name, const struct gaih_service *service,
   else
     {
       struct gaih_addrtuple *atr;
-      atr = at = alloca_account (sizeof (struct gaih_addrtuple), alloca_used);
+      atr = res.at = alloca_account (sizeof (struct gaih_addrtuple),
-      memset (at, '\0', sizeof (struct gaih_addrtuple));
+				     alloca_used);
+      memset (res.at, '\0', sizeof (struct gaih_addrtuple));
 
       if (req->ai_family == AF_UNSPEC)
 	{
-	  at->next = __alloca (sizeof (struct gaih_addrtuple));
+	  res.at->next = __alloca (sizeof (struct gaih_addrtuple));
-	  memset (at->next, '\0', sizeof (struct gaih_addrtuple));
+	  memset (res.at->next, '\0', sizeof (struct gaih_addrtuple));
 	}
 
       if (req->ai_family == AF_UNSPEC || req->ai_family == AF_INET6)
 	{
-	  at->family = AF_INET6;
+	  res.at->family = AF_INET6;
 	  if ((req->ai_flags & AI_PASSIVE) == 0)
-	    memcpy (at->addr, &in6addr_loopback, sizeof (struct in6_addr));
+	    memcpy (res.at->addr, &in6addr_loopback, sizeof (struct in6_addr));
-	  atr = at->next;
+	  atr = res.at->next;
 	}
 
       if (req->ai_family == AF_UNSPEC || req->ai_family == AF_INET)
@@ -1059,10 +1072,10 @@ gaih_inet (const char *name, const struct gaih_service *service,
 
   {
     /* Set up the canonical name if we need it.  */
-    if ((result = process_canonname (req, orig_name, &canon)) != 0)
+    if ((result = process_canonname (req, orig_name, &res)) != 0)
       goto free_and_return;
 
-    struct gaih_addrtuple *at2 = at;
+    struct gaih_addrtuple *at2 = res.at;
     size_t socklen;
     sa_family_t family;
 
@@ -1105,8 +1118,8 @@ gaih_inet (const char *name, const struct gaih_service *service,
 	    ai->ai_addr = (void *) (ai + 1);
 
 	    /* We only add the canonical name once.  */
-	    ai->ai_canonname = (char *) canon;
+	    ai->ai_canonname = res.canon;
-	    canon = NULL;
+	    res.canon = NULL;
 
 #ifdef _HAVE_SA_LEN
 	    ai->ai_addr->sa_len = socklen;
@@ -1152,7 +1165,7 @@ gaih_inet (const char *name, const struct gaih_service *service,
   if (malloc_name)
     free ((char *) name);
   free (addrmem);
-  free (canon);
+  free (res.canon);
 
   return result;
 }