* sysdeps/unix/sysv/linux/bits/local_lim.h: Undefined ARG_MAX if

	<linux/limits.h> has defined it.
	* sysdeps/unix/sysv/linux/sys/param.h: Define NCARGS to the legacy
	ARG_MAX value and prevent ARG_MAX from being defined by the kernel
	headers.
	* sysdeps/unix/sysv/linux/sysconf.c: Define legacy_ARG_MAX and use
	it instead of ARG_MAX.

3 files changed, 30 insertions, 7 deletions

diff --git a/sysdeps/unix/sysv/linux/bits/local_lim.h b/sysdeps/unix/sysv/linux/bits/local_lim.h
index 54a51ee766..ea2cd446d8 100644
--- a/sysdeps/unix/sysv/linux/bits/local_lim.h
+++ b/sysdeps/unix/sysv/linux/bits/local_lim.h
@@ -1,5 +1,5 @@
 /* Minimum guaranteed maximum values for system limits.  Linux version.
-   Copyright (C) 1993-1998, 2000, 2003, 2004 Free Software Foundation, Inc.
+   Copyright (C) 1993-1998,2000,2003,2004,2008 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
@@ -31,6 +31,9 @@
 #ifndef OPEN_MAX
 # define __undef_OPEN_MAX
 #endif
+#ifndef ARG_MAX
+# define __undef_ARG_MAX
+#endif
 
 /* The kernel sources contain a file with all the needed information.  */
 #include <linux/limits.h>
@@ -50,6 +53,11 @@
 # undef OPEN_MAX
 # undef __undef_OPEN_MAX
 #endif
+/* Have to remove ARG_MAX?  */
+#ifdef __undef_ARG_MAX
+# undef ARG_MAX
+# undef __undef_ARG_MAX
+#endif
 
 /* Maximum amount by which a process can descrease its asynchronous I/O
    priority level.  */
diff --git a/sysdeps/unix/sysv/linux/sys/param.h b/sysdeps/unix/sysv/linux/sys/param.h
index 0b0424eb90..19c119a2c8 100644
--- a/sysdeps/unix/sysv/linux/sys/param.h
+++ b/sysdeps/unix/sysv/linux/sys/param.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 1995,1996,1997,2000,2001,2003 Free Software Foundation, Inc.
+/* Copyright (C) 1995-1997,2000,2001,2003,2008 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
@@ -19,10 +19,20 @@
 #ifndef _SYS_PARAM_H
 #define _SYS_PARAM_H	1
 
+#ifndef ARG_MAX
+# define __undef_ARG_MAX
+#endif
+
 #include <limits.h>
 #include <linux/limits.h>
 #include <linux/param.h>
 
+/* The kernel headers defines ARG_MAX.  The value is wrong, though.  */
+#ifndef __undef_ARG_MAX
+# undef ARG_MAX
+# undef __undef_ARG_MAX
+#endif
+
 /* BSD names for some <limits.h> values.  */
 
 #define	NBBY		CHAR_BIT
@@ -31,12 +41,12 @@
 #endif
 #define	MAXSYMLINKS	20
 #define	CANBSIZ		MAX_CANON
-#define	NCARGS		ARG_MAX
 #define MAXPATHLEN	PATH_MAX
-/* The following is not really correct but it is a value we used for a
+/* The following are not really correct but it is a value we used for a
    long time and which seems to be usable.  People should not use NOFILE
-   anyway.  */
+   and NCARGS anyway.  */
 #define NOFILE		256
+#define	NCARGS		131072
 
 
 #include <sys/types.h>
diff --git a/sysdeps/unix/sysv/linux/sysconf.c b/sysdeps/unix/sysv/linux/sysconf.c
index ab9cddc306..f4e36e0c6f 100644
--- a/sysdeps/unix/sysv/linux/sysconf.c
+++ b/sysdeps/unix/sysv/linux/sysconf.c
@@ -27,6 +27,11 @@
 #include <not-cancel.h>
 #include <ldsodefs.h>
 
+/* Legacy value of ARG_MAX.  The macro is now not defined since the
+   actual value varies based on the stack size.  */
+#define legacy_ARG_MAX 131072
+
+
 static long int posix_sysconf (int name);
 
 
@@ -83,10 +88,10 @@ __sysconf (int name)
 	  /* Use getrlimit to get the stack limit.  */
 	  struct rlimit rlimit;
 	  if (__getrlimit (RLIMIT_STACK, &rlimit) == 0)
-	    return MAX (ARG_MAX, rlimit.rlim_cur / 4);
+	    return MAX (legacy_ARG_MAX, rlimit.rlim_cur / 4);
 	}
 
-      return ARG_MAX;
+      return legacy_ARG_MAX;
 
     case _SC_NGROUPS_MAX:
       /* Try to read the information from the /proc/sys/kernel/ngroups_max