getaddrinfo: Convert from extend_alloca to struct scratch_buffer

diff --git a/ChangeLog b/ChangeLog
index 5609b5c..dee85ca 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2016-05-12  Florian Weimer  <fweimer@redhat.com>
+
+       * sysdeps/posix/getaddrinfo.c (gaih_inet_serv): Add tmpbuf
+       argument.  Use scratch buffer instead of extend_alloca.
+       (gethosts): Use scratch buffer instead of extend_alloca.
+       (gaih_inet): Add tmpbuf argument.  Use scratch buffer instead of
+       extend_alloca.
+       (getaddrinfo): Allocate scratch buffer and pass it to gaih_inet.
+
 2016-05-11  Joseph Myers  <joseph@codesourcery.com>
 
        [BZ #20055]

diff --git a/sysdeps/posix/getaddrinfo.c b/sysdeps/posix/getaddrinfo.c
index c670a98..574ce08 100644 (file)
--- a/sysdeps/posix/getaddrinfo.c
+++ b/sysdeps/posix/getaddrinfo.c
@@ -1,3 +1,21 @@
+/* Host and service name lookups using Name Service Switch modules.
+   Copyright (C) 1996-2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
 /* The Inner Net License, Version 2.00
 
   The author(s) grant permission for redistribution and use in source and
@@ -63,6 +81,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <nscd/nscd-client.h>
 #include <nscd/nscd_proto.h>
 #include <resolv/res_hconf.h>
+#include <scratch_buffer.h>
 
 #ifdef HAVE_LIBIDN
 extern int __idna_to_ascii_lz (const char *input, char **output, int flags);
@@ -135,24 +154,24 @@ static const struct addrinfo default_hints =
 
 static int
 gaih_inet_serv (const char *servicename, const struct gaih_typeproto *tp,
-               const struct addrinfo *req, struct gaih_servtuple *st)
+               const struct addrinfo *req, struct gaih_servtuple *st,
+               struct scratch_buffer *tmpbuf)
 {
   struct servent *s;
-  size_t tmpbuflen = 1024;
   struct servent ts;
-  char *tmpbuf;
   int r;
 
   do
     {
-      tmpbuf = __alloca (tmpbuflen);
-
-      r = __getservbyname_r (servicename, tp->name, &ts, tmpbuf, tmpbuflen,
-                            &s);
+      r = __getservbyname_r (servicename, tp->name, &ts,
+                            tmpbuf->data, tmpbuf->length, &s);
       if (r != 0 || s == NULL)
        {
          if (r == ERANGE)
-           tmpbuflen *= 2;
+           {
+             if (!scratch_buffer_grow (tmpbuf))
+               return -EAI_MEMORY;
+           }
          else
            return -EAI_SERVICE;
        }
@@ -227,26 +246,15 @@ convert_hostent_to_gaih_addrtuple (const struct addrinfo *req,
   no_data = 0;                                                               \
   while (1) {                                                                \
     rc = 0;                                                                  \
-    status = DL_CALL_FCT (fct, (name, _family, &th, tmpbuf, tmpbuflen,       \
+    status = DL_CALL_FCT (fct, (name, _family, &th,                          \
+                               tmpbuf->data, tmpbuf->length,                 \
                                &rc, &herrno, NULL, &localcanon));            \
     if (rc != ERANGE || herrno != NETDB_INTERNAL)                            \
       break;                                                                 \
-    if (!malloc_tmpbuf && __libc_use_alloca (alloca_used + 2 * tmpbuflen))    \
-      tmpbuf = extend_alloca_account (tmpbuf, tmpbuflen, 2 * tmpbuflen,              \
-                                     alloca_used);                           \
-    else                                                                     \
+    if (!scratch_buffer_grow (tmpbuf))                                       \
       {                                                                              \
-       char *newp = realloc (malloc_tmpbuf ? tmpbuf : NULL,                  \
-                             2 * tmpbuflen);                                 \
-       if (newp == NULL)                                                     \
-         {                                                                   \
-           _res.options |= old_res_options & RES_USE_INET6;                  \
-           result = -EAI_MEMORY;                                             \
-           goto free_and_return;                                             \
-         }                                                                   \
-       tmpbuf = newp;                                                        \
-       malloc_tmpbuf = true;                                                 \
-       tmpbuflen = 2 * tmpbuflen;                                            \
+       result = -EAI_MEMORY;                                                 \
+       goto free_and_return;                                                 \
       }                                                                              \
   }                                                                          \
   if (status == NSS_STATUS_SUCCESS && rc == 0)                               \
@@ -308,7 +316,7 @@ extern service_user *__nss_hosts_database attribute_hidden;
 static int
 gaih_inet (const char *name, const struct gaih_service *service,
           const struct addrinfo *req, struct addrinfo **pai,
-          unsigned int *naddrs)
+          unsigned int *naddrs, struct scratch_buffer *tmpbuf)
 {
   const struct gaih_typeproto *tp = gaih_inet_typeproto;
   struct gaih_servtuple *st = (struct gaih_servtuple *) &nullserv;
@@ -317,7 +325,10 @@ gaih_inet (const char *name, const struct gaih_service *service,
   bool got_ipv6 = false;
   const char *canon = NULL;
   const char *orig_name = name;
-  size_t alloca_used = 0;
+
+  /* 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)
     {
@@ -352,7 +363,7 @@ gaih_inet (const char *name, const struct gaih_service *service,
              st = (struct gaih_servtuple *)
                alloca_account (sizeof (struct gaih_servtuple), alloca_used);
 
-             if ((rc = gaih_inet_serv (service->name, tp, req, st)))
+             if ((rc = gaih_inet_serv (service->name, tp, req, st, tmpbuf)))
                return rc;
            }
          else
@@ -377,7 +388,8 @@ gaih_inet (const char *name, const struct gaih_service *service,
                    alloca_account (sizeof (struct gaih_servtuple),
                                    alloca_used);
 
-                 if ((rc = gaih_inet_serv (service->name, tp, req, newp)))
+                 if ((rc = gaih_inet_serv (service->name,
+                                           tp, req, newp, tmpbuf)))
                    {
                      if (rc)
                        continue;
@@ -438,9 +450,8 @@ gaih_inet (const char *name, const struct gaih_service *service,
   struct gaih_addrtuple *addrmem = NULL;
   bool malloc_canonbuf = false;
   char *canonbuf = NULL;
-  bool malloc_tmpbuf = false;
-  char *tmpbuf = NULL;
   int result = 0;
+
   if (name != NULL)
     {
       at = alloca_account (sizeof (struct gaih_addrtuple), alloca_used);
@@ -608,11 +619,6 @@ gaih_inet (const char *name, const struct gaih_service *service,
          if (req->ai_family == AF_INET
              && (req->ai_flags & AI_CANONNAME) == 0)
            {
-             /* Allocate additional room for struct host_data.  */
-             size_t tmpbuflen = (512 + MAX_NR_ALIASES * sizeof(char*)
-                                 + 16 * sizeof(char));
-             assert (tmpbuf == NULL);
-             tmpbuf = alloca_account (tmpbuflen, alloca_used);
              int rc;
              struct hostent th;
              struct hostent *h;
@@ -620,28 +626,15 @@ gaih_inet (const char *name, const struct gaih_service *service,
 
              while (1)
                {
-                 rc = __gethostbyname2_r (name, AF_INET, &th, tmpbuf,
-                                          tmpbuflen, &h, &herrno);
+                 rc = __gethostbyname2_r (name, AF_INET, &th,
+                                          tmpbuf->data, tmpbuf->length,
+                                          &h, &herrno);
                  if (rc != ERANGE || herrno != NETDB_INTERNAL)
                    break;
-
-                 if (!malloc_tmpbuf
-                     && __libc_use_alloca (alloca_used + 2 * tmpbuflen))
-                   tmpbuf = extend_alloca_account (tmpbuf, tmpbuflen,
-                                                   2 * tmpbuflen,
-                                                   alloca_used);
-                 else
+                 if (!scratch_buffer_grow (tmpbuf))
                    {
-                     char *newp = realloc (malloc_tmpbuf ? tmpbuf : NULL,
-                                           2 * tmpbuflen);
-                     if (newp == NULL)
-                       {
-                         result = -EAI_MEMORY;
-                         goto free_and_return;
-                       }
-                     tmpbuf = newp;
-                     malloc_tmpbuf = true;
-                     tmpbuflen = 2 * tmpbuflen;
+                     result = -EAI_MEMORY;
+                     goto free_and_return;
                    }
                }
 
@@ -835,22 +828,6 @@ gaih_inet (const char *name, const struct gaih_service *service,
          old_res_options = _res.options;
          _res.options &= ~RES_USE_INET6;
 
-         size_t tmpbuflen = 1024 + sizeof(struct gaih_addrtuple);
-         malloc_tmpbuf = !__libc_use_alloca (alloca_used + tmpbuflen);
-         assert (tmpbuf == NULL);
-         if (!malloc_tmpbuf)
-           tmpbuf = alloca_account (tmpbuflen, alloca_used);
-         else
-           {
-             tmpbuf = malloc (tmpbuflen);
-             if (tmpbuf == NULL)
-               {
-                 _res.options |= old_res_options & RES_USE_INET6;
-                 result = -EAI_MEMORY;
-                 goto free_and_return;
-               }
-           }
-
          while (!no_more)
            {
              no_data = 0;
@@ -868,8 +845,9 @@ gaih_inet (const char *name, const struct gaih_service *service,
                  while (1)
                    {
                      rc = 0;
-                     status = DL_CALL_FCT (fct4, (name, pat, tmpbuf,
-                                                  tmpbuflen, &rc, &herrno,
+                     status = DL_CALL_FCT (fct4, (name, pat,
+                                                  tmpbuf->data, tmpbuf->length,
+                                                  &rc, &herrno,
                                                   NULL));
                      if (status == NSS_STATUS_SUCCESS)
                        break;
@@ -883,24 +861,11 @@ gaih_inet (const char *name, const struct gaih_service *service,
                          break;
                        }
 
-                     if (!malloc_tmpbuf
-                         && __libc_use_alloca (alloca_used + 2 * tmpbuflen))
-                       tmpbuf = extend_alloca_account (tmpbuf, tmpbuflen,
-                                                       2 * tmpbuflen,
-                                                       alloca_used);
-                     else
+                     if (!scratch_buffer_grow (tmpbuf))
                        {
-                         char *newp = realloc (malloc_tmpbuf ? tmpbuf : NULL,
-                                               2 * tmpbuflen);
-                         if (newp == NULL)
-                           {
-                             _res.options |= old_res_options & RES_USE_INET6;
-                             result = -EAI_MEMORY;
-                             goto free_and_return;
-                           }
-                         tmpbuf = newp;
-                         malloc_tmpbuf = true;
-                         tmpbuflen = 2 * tmpbuflen;
+                         _res.options |= old_res_options & RES_USE_INET6;
+                         result = -EAI_MEMORY;
+                         goto free_and_return;
                        }
                    }
 
@@ -1287,8 +1252,6 @@ gaih_inet (const char *name, const struct gaih_service *service,
     free (addrmem);
   if (malloc_canonbuf)
     free (canonbuf);
-  if (malloc_tmpbuf)
-    free (tmpbuf);
 
   return result;
 }
@@ -2423,7 +2386,11 @@ getaddrinfo (const char *name, const char *service,
   if (hints->ai_family == AF_UNSPEC || hints->ai_family == AF_INET
       || hints->ai_family == AF_INET6)
     {
-      last_i = gaih_inet (name, pservice, hints, end, &naddrs);
+      struct scratch_buffer tmpbuf;
+      scratch_buffer_init (&tmpbuf);
+      last_i = gaih_inet (name, pservice, hints, end, &naddrs, &tmpbuf);
+      scratch_buffer_free (&tmpbuf);
+
       if (last_i != 0)
        {
          freeaddrinfo (p);