[PATCH] Fix gethostbyname when using nscd

[PATCH] Fix gethostbyname when using nscd

[Jakub Jelinek]

Hi!

The first hunk is the most important.  Fixes a bug where e.g. with overly
long /etc/hosts entries gethostbyname etc. work only when nscd is turned
off but fail when it is running.  The problem is that if h_errno is not set
to NETDB_INTERNAL, the non-_r functions don't consider ERANGE as being
because the buffer was too small and don't retry with a larger size.

The rest of the changes is just something I have noticed during the
debugging - there were a few places which grew the buffer sizes linearly,
which is really slow for very big answers.  The other places have been
fixed before already to DTRT.

2005-02-21  Jakub Jelinek  <jakub@redhat.com>

	* nscd/nscd_gethst_r.c (nscd_gethst_r): Set *h_errnop to
	NETDB_INTERNAL if buffer is too small.

	* nscd/hstcache.c (INCR): Remove.
	(addhstbyX): Double buflen in each iteration rather than add INCR.
	* nscd/grpcache.c (INCR): Remove.
	(addgrbyX): Double buflen in each iteration rather than add INCR.
	* nscd/pwdcache.c (INCR): Remove.
	(addpwbyX): Double buflen in each iteration rather than add INCR.

--- libc/nscd/nscd_gethst_r.c.jj	2004-11-10 10:30:32.000000000 +0100
+++ libc/nscd/nscd_gethst_r.c	2005-02-21 21:34:28.644218762 +0100
@@ -1,4 +1,4 @@
-/* Copyright (C) 1998-2002, 2003, 2004 Free Software Foundation, Inc.
+/* Copyright (C) 1998-2002, 2003, 2004, 2005 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
 
@@ -218,6 +218,7 @@ nscd_gethst_r (const char *key, size_t k
 						   ? INADDRSZ : IN6ADDRSZ)))
 	{
 	no_room:
+	  *h_errnop = NETDB_INTERNAL;
 	  __set_errno (ERANGE);
 	  retval = ERANGE;
 	  goto out_close;
--- libc/nscd/hstcache.c.jj	2005-01-26 18:36:40.000000000 +0100
+++ libc/nscd/hstcache.c	2005-02-21 21:28:50.806168914 +0100
@@ -1,5 +1,5 @@
 /* Cache handling for host lookup.
-   Copyright (C) 1998-2002, 2003, 2004 Free Software Foundation, Inc.
+   Copyright (C) 1998-2002, 2003, 2004, 2005 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
 
@@ -453,11 +453,10 @@ addhstbyX (struct database_dyn *db, int 
     {
       char *old_buffer = buffer;
       errno = 0;
-#define INCR 1024
 
       if (__builtin_expect (buflen > 32768, 0))
 	{
-	  buflen += INCR;
+	  buflen *= 2;
 	  buffer = (char *) realloc (use_malloc ? buffer : NULL, buflen);
 	  if (buffer == NULL)
 	    {
@@ -478,7 +477,7 @@ addhstbyX (struct database_dyn *db, int 
       else
 	/* Allocate a new buffer on the stack.  If possible combine it
 	   with the previously allocated buffer.  */
-	buffer = (char *) extend_alloca (buffer, buflen, buflen + INCR);
+	buffer = (char *) extend_alloca (buffer, buflen, 2 * buflen);
     }
 
 #if 0
--- libc/nscd/grpcache.c.jj	2005-01-26 18:36:40.000000000 +0100
+++ libc/nscd/grpcache.c	2005-02-21 21:30:49.876047695 +0100
@@ -1,5 +1,5 @@
 /* Cache handling for group lookup.
-   Copyright (C) 1998-2002, 2003, 2004 Free Software Foundation, Inc.
+   Copyright (C) 1998-2002, 2003, 2004, 2005 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
 
@@ -429,11 +429,10 @@ addgrbyX (struct database_dyn *db, int f
     {
       char *old_buffer = buffer;
       errno = 0;
-#define INCR 1024
 
       if (__builtin_expect (buflen > 32768, 0))
 	{
-	  buflen += INCR;
+	  buflen *= 2;
 	  buffer = (char *) realloc (use_malloc ? buffer : NULL, buflen);
 	  if (buffer == NULL)
 	    {
@@ -454,7 +453,7 @@ addgrbyX (struct database_dyn *db, int f
       else
 	/* Allocate a new buffer on the stack.  If possible combine it
 	   with the previously allocated buffer.  */
-	buffer = (char *) extend_alloca (buffer, buflen, buflen + INCR);
+	buffer = (char *) extend_alloca (buffer, buflen, 2 * buflen);
     }
 
 #if 0
--- libc/nscd/pwdcache.c.jj	2005-01-26 18:36:40.000000000 +0100
+++ libc/nscd/pwdcache.c	2005-02-21 21:31:14.872612500 +0100
@@ -1,5 +1,5 @@
 /* Cache handling for passwd lookup.
-   Copyright (C) 1998-2002, 2003, 2004 Free Software Foundation, Inc.
+   Copyright (C) 1998-2002, 2003, 2004, 2005 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
 
@@ -425,11 +425,10 @@ addpwbyX (struct database_dyn *db, int f
     {
       char *old_buffer = buffer;
       errno = 0;
-#define INCR 1024
 
       if (__builtin_expect (buflen > 32768, 0))
 	{
-	  buflen += INCR;
+	  buflen *= 2;
 	  buffer = (char *) realloc (use_malloc ? buffer : NULL, buflen);
 	  if (buffer == NULL)
 	    {
@@ -450,7 +449,7 @@ addpwbyX (struct database_dyn *db, int f
       else
 	/* Allocate a new buffer on the stack.  If possible combine it
 	   with the previously allocated buffer.  */
-	buffer = (char *) extend_alloca (buffer, buflen, buflen + INCR);
+	buffer = (char *) extend_alloca (buffer, buflen, 2 * buflen);
     }
 
 #if 0

	Jakub

Re: [PATCH] Fix gethostbyname when using nscd

[Ulrich Drepper]

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Applied.

--
➧ Ulrich Drepper ➧ Red Hat, Inc. ➧ 444 Castro St ➧ Mountain View, CA ❖

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