config: Adjust AM_CPPFLAGS for srcdir and .. path includes

When building with clang and libc++ some standard headers might try
including <stack> even when no source file requests such include
directly. When building with srcdir == builddir this might clash in
the src dir since we then build a stack binary there and the src dir
also has srcfiles.cxx which might include some standard c++ headers.

Work around this by removing -I.. from AM_CPPFLAGS and replacing it
with -I(abs_top_builddir) where the <config.h> file can be found. And
use -iquote for srcdir so it doesn't get included in the search path
for the system <header> includes (only for "header" includes).

Note that DEFAULT_INCLUDES might add . and srcdir back.  So
DEFAULT_INCLUDES is disabled explicitly in src/Makefile.am (where the
stack binary is build). We could also use the nostdinc automake option
to completely suppress that, but that needs more auditing of various
installed vs not-installed header files.

	* config/eu.am (AM_CPPFLAGS): Use -iquote for $(srcdir) and
        replace -I.. with -I$(abs_top_builddir).
	* libdw/libdwP.h: Include "libdw.h" and "dwarf.h" instead of
        the system headers <libdw.h> and <dwarf.h>.

https://sourceware.org/bugzilla/show_bug.cgi?id=33103

Signed-off-by: Mark Wielaard <mark@klomp.org>

diff --git a/config/eu.am b/config/eu.am
index 5157a34ee5525b4bb01dbc576f84f5e55267f5aa..0f4aa9f0364c24a9e642bd1fa9bd64384f082ac8 100644 (file)
--- a/config/eu.am
+++ b/config/eu.am
@@ -1,7 +1,7 @@
 ## Common automake fragments for elfutils subdirectory makefiles.
 ##
 ## Copyright (C) 2010, 2014, 2016 Red Hat, Inc.
-## Copyright (C) 2023, Mark J. Wielaard <mark@klomp.org>
+## Copyright (C) 2023, 2025 Mark J. Wielaard <mark@klomp.org>
 ##
 ## This file is part of elfutils.
 ##
@@ -31,7 +31,24 @@
 ##
 
 DEFS = -D_GNU_SOURCE -DHAVE_CONFIG_H -DLOCALEDIR='"${localedir}"'
-AM_CPPFLAGS = -iquote . -I$(srcdir) -I$(top_srcdir)/lib -I..
+
+# -iquote dirs are just for "header" includes, -I for both <header>
+# and "header" includes. We don't want system <header> includes to
+# search . and srcdir. We do want the headers under lib and the abs
+# top build dir (for config.h).
+#
+# This is mainly to prevent things like #include <stack> to
+# accidentially import the stack binary instead of the standard C++
+# header file (which apparently clang plus libc++ do indirectly).
+# https://bugs.gentoo.org/925241
+# https://sourceware.org/bugzilla/show_bug.cgi?id=33103
+#
+# Note that DEFAULT_INCLUDES might add . and srcdir back.  So
+# DEFAULT_INCLUDES is disabled explicitly in src/Makefile.am (where
+# the stack binary is build). We could also use the nostdinc automake
+# option to completely suppress that, but that needs more auditing of
+# various installed vs not-installed header files.
+AM_CPPFLAGS = -iquote. -iquote$(srcdir) -I$(top_srcdir)/lib -I$(abs_top_builddir)
 
 # Drop the 'u' flag that automake adds by default. It is incompatible
 # with deterministic archives.

diff --git a/libdw/libdwP.h b/libdw/libdwP.h
index 25d53d31c7c84f2042cd73cfe3ff2223ace54ac0..b77db1423fe0bb68e4634b9f3b1be6ebe50f0e81 100644 (file)
--- a/libdw/libdwP.h
+++ b/libdw/libdwP.h
@@ -32,8 +32,8 @@
 #include <stdbool.h>
 #include <pthread.h>
 
-#include <libdw.h>
-#include <dwarf.h>
+#include "libdw.h"
+#include "dwarf.h"
 #include "eu-search.h"