# HG changeset patch
# User Eric Blake <eblake@redhat.com>
# Date 1308776544 21600
# Node ID 94b3a0b47189dac72244ef3708bc69b917da93b6
# Parent  517a0b73b86b522b86c5fd28e1fcf672256a8434
maint.mk: add syntax-check to avoid char[PATH_MAX]

POSIX allows PATH_MAX to be undefined.  And even if you use the
gnulib pathmax module, where "pathmax.h" guarantees a definition,
the definition might not be constant or might be so large as to
be wasteful or cause stack overflows.  PATH_MAX should only be
used as a limit or hueristic, not an array size.

* top/maint.mk (sc_prohibit_path_max_array): New rule.

Signed-off-by: Eric Blake <eblake@redhat.com>

diff --git a/ChangeLog b/ChangeLog
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
 2011-06-22  Eric Blake  <eblake@redhat.com>
 
+	maint.mk: add syntax-check to avoid char[PATH_MAX]
+	* top/maint.mk (sc_prohibit_path_max_array): New rule.
+
 	stat: be robust to PATH_MAX definition
 	* lib/stat.c (rpl_stat): Require reasonable PATH_MAX.
 	* modules/stat (Depends-on): Add verify.
diff --git a/top/maint.mk b/top/maint.mk
--- a/top/maint.mk
+++ b/top/maint.mk
@@ -1106,6 +1106,7 @@
 # the other init.sh-using tests also get it right.
 _hv_file ?= $(srcdir)/tests/help-version
 _hv_regex_weak ?= ^ *\. .*/init\.sh"
+# Fix syntax-highlighters "
 _hv_regex_strong ?= ^ *\. "\$${srcdir=\.}/init\.sh"
 sc_cross_check_PATH_usage_in_tests:
 	@if test -f $(_hv_file); then					\
@@ -1133,6 +1134,14 @@
 	halt='Use 0 or 1 for macro values'				\
 	  $(_sc_search_regexp)
 
+# Even if you use pathmax.h to guarantee that PATH_MAX is defined, it might
+# not be constant.  In general, use PATH_MAX as a limit, not an array
+# allocation bound.
+sc_prohibit_path_max_array:
+	@prohibit='\[PATH''_MAX'					\
+	halt='Avoid arrays of size PATH_MAX'				\
+	  $(_sc_search_regexp)
+
 sc_vulnerable_makefile_CVE-2009-4029:
 	@prohibit='perm -777 -exec chmod a\+rwx|chmod 777 \$$\(distdir\)' \
 	in_files=$$(find $(srcdir) -name Makefile.in)			\