gaih_inet: Simplify service resolution

Refactor the code to split out the service resolution code into a
separate function.  Allocate the service tuples array just once to the
size of the typeproto array, thus avoiding the unnecessary pointer
chasing and stack allocations.

Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: DJ Delorie <dj@redhat.com>

diff --git a/sysdeps/posix/getaddrinfo.c b/sysdeps/posix/getaddrinfo.c
index e9deb2da6a81c5333c3d4ce04a82f4eb7972d9ae..dae5e9f55fd1b5a57a842c52bbf45cb70be15a9d 100644 (file)
--- a/sysdeps/posix/getaddrinfo.c
+++ b/sysdeps/posix/getaddrinfo.c
@@ -100,14 +100,12 @@ struct gaih_service
 
 struct gaih_servtuple
   {
-    struct gaih_servtuple *next;
     int socktype;
     int protocol;
     int port;
+    bool set;
   };
 
-static const struct gaih_servtuple nullserv;
-
 
 struct gaih_typeproto
   {
@@ -180,11 +178,11 @@ gaih_inet_serv (const char *servicename, const struct gaih_typeproto *tp,
     }
   while (r);
 
-  st->next = NULL;
   st->socktype = tp->socktype;
   st->protocol = ((tp->protoflag & GAI_PROTO_PROTOANY)
                  ? req->ai_protocol : tp->protocol);
   st->port = s->s_port;
+  st->set = true;
 
   return 0;
 }
@@ -375,20 +373,11 @@ process_canonname (const struct addrinfo *req, const char *orig_name,
 }
 
 static int
-gaih_inet (const char *name, const struct gaih_service *service,
-          const struct addrinfo *req, struct addrinfo **pai,
-          unsigned int *naddrs, struct scratch_buffer *tmpbuf)
+get_servtuples (const struct gaih_service *service, const struct addrinfo *req,
+               struct gaih_servtuple *st, struct scratch_buffer *tmpbuf)
 {
+  int i;
   const struct gaih_typeproto *tp = gaih_inet_typeproto;
-  struct gaih_servtuple *st = (struct gaih_servtuple *) &nullserv;
-  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
-     function.  */
-  size_t alloca_used = sizeof (struct scratch_buffer);
 
   if (req->ai_protocol || req->ai_socktype)
     {
@@ -410,98 +399,88 @@ gaih_inet (const char *name, const struct gaih_service *service,
        }
     }
 
-  int port = 0;
-  if (service != NULL)
+  if (service != NULL && (tp->protoflag & GAI_PROTO_NOSERVICE) != 0)
+    return -EAI_SERVICE;
+
+  if (service == NULL || service->num >= 0)
     {
-      if ((tp->protoflag & GAI_PROTO_NOSERVICE) != 0)
-       return -EAI_SERVICE;
+      int port = service != NULL ? htons (service->num) : 0;
 
-      if (service->num < 0)
+      if (req->ai_socktype || req->ai_protocol)
        {
-         if (tp->name[0])
-           {
-             st = (struct gaih_servtuple *)
-               alloca_account (sizeof (struct gaih_servtuple), alloca_used);
-
-             int rc = gaih_inet_serv (service->name, tp, req, st, tmpbuf);
-             if (__glibc_unlikely (rc != 0))
-               return rc;
-           }
-         else
-           {
-             struct gaih_servtuple **pst = &st;
-             for (tp++; tp->name[0]; tp++)
-               {
-                 struct gaih_servtuple *newp;
+         st[0].socktype = tp->socktype;
+         st[0].protocol = ((tp->protoflag & GAI_PROTO_PROTOANY)
+                         ? req->ai_protocol : tp->protocol);
+         st[0].port = port;
+         st[0].set = true;
 
-                 if ((tp->protoflag & GAI_PROTO_NOSERVICE) != 0)
-                   continue;
+         return 0;
+       }
 
-                 if (req->ai_socktype != 0
-                     && req->ai_socktype != tp->socktype)
-                   continue;
-                 if (req->ai_protocol != 0
-                     && !(tp->protoflag & GAI_PROTO_PROTOANY)
-                     && req->ai_protocol != tp->protocol)
-                   continue;
+      /* Neither socket type nor protocol is set.  Return all socket types
+        we know about.  */
+      for (i = 0, ++tp; tp->name[0]; ++tp)
+       if (tp->defaultflag)
+         {
+           st[i].socktype = tp->socktype;
+           st[i].protocol = tp->protocol;
+           st[i].port = port;
+           st[i++].set = true;
+         }
 
-                 newp = (struct gaih_servtuple *)
-                   alloca_account (sizeof (struct gaih_servtuple),
-                                   alloca_used);
+      return 0;
+    }
 
-                 if (gaih_inet_serv (service->name,
-                                     tp, req, newp, tmpbuf) != 0)
-                   continue;
+  if (tp->name[0])
+    return gaih_inet_serv (service->name, tp, req, st, tmpbuf);
 
-                 *pst = newp;
-                 pst = &(newp->next);
-               }
-             if (st == (struct gaih_servtuple *) &nullserv)
-               return -EAI_SERVICE;
-           }
-       }
-      else
-       {
-         port = htons (service->num);
-         goto got_port;
-       }
-    }
-  else
+  for (i = 0, tp++; tp->name[0]; tp++)
     {
-    got_port:
+      if ((tp->protoflag & GAI_PROTO_NOSERVICE) != 0)
+       continue;
 
-      if (req->ai_socktype || req->ai_protocol)
-       {
-         st = alloca_account (sizeof (struct gaih_servtuple), alloca_used);
-         st->next = NULL;
-         st->socktype = tp->socktype;
-         st->protocol = ((tp->protoflag & GAI_PROTO_PROTOANY)
-                         ? req->ai_protocol : tp->protocol);
-         st->port = port;
-       }
-      else
-       {
-         /* Neither socket type nor protocol is set.  Return all socket types
-            we know about.  */
-         struct gaih_servtuple **lastp = &st;
-         for (++tp; tp->name[0]; ++tp)
-           if (tp->defaultflag)
-             {
-               struct gaih_servtuple *newp;
+      if (req->ai_socktype != 0
+         && req->ai_socktype != tp->socktype)
+       continue;
+      if (req->ai_protocol != 0
+         && !(tp->protoflag & GAI_PROTO_PROTOANY)
+         && req->ai_protocol != tp->protocol)
+       continue;
 
-               newp = alloca_account (sizeof (struct gaih_servtuple),
-                                      alloca_used);
-               newp->next = NULL;
-               newp->socktype = tp->socktype;
-               newp->protocol = tp->protocol;
-               newp->port = port;
+      if (gaih_inet_serv (service->name,
+                         tp, req, &st[i], tmpbuf) != 0)
+       continue;
 
-               *lastp = newp;
-               lastp = &newp->next;
-             }
-       }
+      i++;
     }
 
+  if (!st[0].set)
+    return -EAI_SERVICE;
+
+  return 0;
+}
+
+static int
+gaih_inet (const char *name, const struct gaih_service *service,
+          const struct addrinfo *req, struct addrinfo **pai,
+          unsigned int *naddrs, struct scratch_buffer *tmpbuf)
+{
+  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
+     function.  */
+  size_t alloca_used = sizeof (struct scratch_buffer);
+
+  int rc;
+  if ((rc = get_servtuples (service, req, st, tmpbuf)) != 0)
+    return rc;
+
   bool malloc_name = false;
   struct gaih_addrtuple *addrmem = NULL;
   int result = 0;
@@ -1083,7 +1062,6 @@ gaih_inet (const char *name, const struct gaih_service *service,
     if ((result = process_canonname (req, orig_name, &canon)) != 0)
       goto free_and_return;
 
-    struct gaih_servtuple *st2;
     struct gaih_addrtuple *at2 = at;
     size_t socklen;
     sa_family_t family;
@@ -1109,7 +1087,7 @@ gaih_inet (const char *name, const struct gaih_service *service,
        else
          socklen = sizeof (struct sockaddr_in);
 
-       for (st2 = st; st2 != NULL; st2 = st2->next)
+       for (int i = 0; st[i].set; i++)
          {
            struct addrinfo *ai;
            ai = *pai = malloc (sizeof (struct addrinfo) + socklen);
@@ -1121,8 +1099,8 @@ gaih_inet (const char *name, const struct gaih_service *service,
 
            ai->ai_flags = req->ai_flags;
            ai->ai_family = family;
-           ai->ai_socktype = st2->socktype;
-           ai->ai_protocol = st2->protocol;
+           ai->ai_socktype = st[i].socktype;
+           ai->ai_protocol = st[i].protocol;
            ai->ai_addrlen = socklen;
            ai->ai_addr = (void *) (ai + 1);
 
@@ -1144,7 +1122,7 @@ gaih_inet (const char *name, const struct gaih_service *service,
                struct sockaddr_in6 *sin6p =
                  (struct sockaddr_in6 *) ai->ai_addr;
 
-               sin6p->sin6_port = st2->port;
+               sin6p->sin6_port = st[i].port;
                sin6p->sin6_flowinfo = 0;
                memcpy (&sin6p->sin6_addr,
                        at2->addr, sizeof (struct in6_addr));
@@ -1154,7 +1132,7 @@ gaih_inet (const char *name, const struct gaih_service *service,
              {
                struct sockaddr_in *sinp =
                  (struct sockaddr_in *) ai->ai_addr;
-               sinp->sin_port = st2->port;
+               sinp->sin_port = st[i].port;
                memcpy (&sinp->sin_addr,
                        at2->addr, sizeof (struct in_addr));
                memset (sinp->sin_zero, '\0', sizeof (sinp->sin_zero));