2012-04-12  Jeff Law  <law@redhat.com>

	* nscd/grpcache.c (cache_addgr): Track alloca usage with alloca_account.

	Do not allocate DATASET on the stack if it's too large.  Free DATASET

	if needed.

diff -rcp a/nscd/grpcache.c b/nscd/grpcache.c

*** a/nscd/grpcache.c	Wed Apr 11 12:50:07 2012

--- b/nscd/grpcache.c	Wed Apr 11 21:45:58 2012

*************** cache_addgr (struct database_dyn *db, in

*** 178,184 ****

        char *cp;

        const size_t key_len = strlen (key);

        const size_t buf_len = 3 * sizeof (grp->gr_gid) + key_len + 1;

!       char *buf = alloca (buf_len);

        ssize_t n;

        size_t cnt;

--- 178,185 ----

        char *cp;

        const size_t key_len = strlen (key);

        const size_t buf_len = 3 * sizeof (grp->gr_gid) + key_len + 1;

!       size_t alloca_used = 0;

!       char *buf = alloca_account (buf_len, alloca_used);

        ssize_t n;

        size_t cnt;

*************** cache_addgr (struct database_dyn *db, in

*** 190,196 ****

        /* Determine the length of all members.  */

        while (grp->gr_mem[gr_mem_cnt])

  	++gr_mem_cnt;

!       gr_mem_len = (uint32_t *) alloca (gr_mem_cnt * sizeof (uint32_t));

        for (gr_mem_cnt = 0; grp->gr_mem[gr_mem_cnt]; ++gr_mem_cnt)

  	{

  	  gr_mem_len[gr_mem_cnt] = strlen (grp->gr_mem[gr_mem_cnt]) + 1;

--- 191,198 ----

        /* Determine the length of all members.  */

        while (grp->gr_mem[gr_mem_cnt])

  	++gr_mem_cnt;

!       gr_mem_len = (uint32_t *) alloca_account (gr_mem_cnt * sizeof (uint32_t),

! 						alloca_used);

        for (gr_mem_cnt = 0; grp->gr_mem[gr_mem_cnt]; ++gr_mem_cnt)

  	{

  	  gr_mem_len[gr_mem_cnt] = strlen (grp->gr_mem[gr_mem_cnt]) + 1;

*************** cache_addgr (struct database_dyn *db, in

*** 205,214 ****

  	 change.  Allocate memory on the cache since it is likely

  	 discarded anyway.  If it turns out to be necessary to have a

  	 new record we can still allocate real memory.  */

!       bool alloca_used = false;

        dataset = NULL;

!       if (he == NULL)

  	dataset = (struct dataset *) mempool_alloc (db, total + n, 1);

        if (dataset == NULL)

--- 207,216 ----

  	 change.  Allocate memory on the cache since it is likely

  	 discarded anyway.  If it turns out to be necessary to have a

  	 new record we can still allocate real memory.  */

!       bool dataset_in_stack_or_freed = false;

        dataset = NULL;

!       if (he == NULL || ! __libc_use_alloca (alloca_used + total + n))

  	dataset = (struct dataset *) mempool_alloc (db, total + n, 1);

        if (dataset == NULL)

*************** cache_addgr (struct database_dyn *db, in

*** 216,225 ****

  	  /* We cannot permanently add the result in the moment.  But

  	     we can provide the result as is.  Store the data in some

  	     temporary memory.  */

! 	  dataset = (struct dataset *) alloca (total + n);

  	  /* We cannot add this record to the permanent database.  */

! 	  alloca_used = true;

  	}

        dataset->head.allocsize = total + n;

--- 218,227 ----

  	  /* We cannot permanently add the result in the moment.  But

  	     we can provide the result as is.  Store the data in some

  	     temporary memory.  */

! 	  dataset = (struct dataset *) alloca_account (total + n, alloca_used);

  	  /* We cannot add this record to the permanent database.  */

! 	  dataset_in_stack_or_freed = true;

  	}

        dataset->head.allocsize = total + n;

*************** cache_addgr (struct database_dyn *db, in

*** 273,278 ****

--- 275,288 ----

  		 allocated on the stack and need not be freed.  */

  	      dh->timeout = dataset->head.timeout;

  	      ++dh->nreloads;

+ 

+ 	      /* If the new record was not allocated on the stack, then it must

+ 		 be freed.  Note that it can no longer be used.  */

+ 	      if (! dataset_in_stack_or_freed)

+ 		{

+ 		  free (dataset);

+ 		  dataset_in_stack_or_freed = true;

+ 		}

  	    }

  	  else

  	    {

*************** cache_addgr (struct database_dyn *db, in

*** 288,294 ****

  		  key_copy = (char *) newp + (key_copy - (char *) dataset);

  		  dataset = memcpy (newp, dataset, total + n);

! 		  alloca_used = false;

  		}

  	      /* Mark the old record as obsolete.  */

--- 298,304 ----

  		  key_copy = (char *) newp + (key_copy - (char *) dataset);

  		  dataset = memcpy (newp, dataset, total + n);

! 		  dataset_in_stack_or_freed = false;

  		}

  	      /* Mark the old record as obsolete.  */

*************** cache_addgr (struct database_dyn *db, in

*** 303,309 ****

  	  assert (fd != -1);

  #ifdef HAVE_SENDFILE

! 	  if (__builtin_expect (db->mmap_used, 1) && !alloca_used)

  	    {

  	      assert (db->wr_fd != -1);

  	      assert ((char *) &dataset->resp > (char *) db->data);

--- 313,319 ----

  	  assert (fd != -1);

  #ifdef HAVE_SENDFILE

! 	  if (__builtin_expect (db->mmap_used, 1) && !dataset_in_stack_or_freed)

  	    {

  	      assert (db->wr_fd != -1);

  	      assert ((char *) &dataset->resp > (char *) db->data);

*************** cache_addgr (struct database_dyn *db, in

*** 330,336 ****

        /* Add the record to the database.  But only if it has not been

  	 stored on the stack.  */

!       if (! alloca_used)

  	{

  	  /* If necessary, we also propagate the data to disk.  */

  	  if (db->persistent)

--- 340,346 ----

        /* Add the record to the database.  But only if it has not been

  	 stored on the stack.  */

!       if (! dataset_in_stack_or_freed)

  	{

  	  /* If necessary, we also propagate the data to disk.  */

  	  if (db->persistent)