From 99f1e61b2957226254a116fde7fd73bf07034012 Mon Sep 17 00:00:00 2001
From: Khem Raj <raj.khem@gmail.com>
Date: Mon, 8 Mar 2021 16:04:20 -0800
Subject: [PATCH] gcc: poison-system-directories

Add /sw/include and /opt/include based on the original
zecke-no-host-includes.patch patch.  The original patch checked for
/usr/include, /sw/include and /opt/include and then triggered a failure and
aborted.

Instead, we add the two missing items to the current scan.  If the user
wants this to be a failure, they can add "-Werror=poison-system-directories".

Upstream-Status: Pending
Signed-off-by: Mark Hatle <mark.hatle@windriver.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>
---
 gcc/common.opt      |  4 ++++
 gcc/config.in       | 10 ++++++++++
 gcc/configure       | 19 +++++++++++++++++++
 gcc/configure.ac    | 16 ++++++++++++++++
 gcc/doc/invoke.texi |  9 +++++++++
 gcc/gcc.cc          | 15 ++++++++++++---
 gcc/incpath.cc      | 21 +++++++++++++++++++++
 7 files changed, 91 insertions(+), 3 deletions(-)

diff --git a/gcc/common.opt b/gcc/common.opt
index 8a0dafc52..0357868e2 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -710,6 +710,10 @@ Wreturn-local-addr
 Common Var(warn_return_local_addr) Init(1) Warning
 Warn about returning a pointer/reference to a local or temporary variable.
 
+Wpoison-system-directories
+Common Var(flag_poison_system_directories) Init(1) Warning
+Warn for -I and -L options using system directories if cross compiling
+
 Wshadow
 Common Var(warn_shadow) Warning
 Warn when one variable shadows another.  Same as -Wshadow=global.
diff --git a/gcc/config.in b/gcc/config.in
index 64c27c9cf..a693cb8a8 100644
--- a/gcc/config.in
+++ b/gcc/config.in
@@ -230,6 +230,16 @@
 #endif
 
 
+/* Define to warn for use of native system header directories */
+#ifndef USED_FOR_TARGET
+#undef ENABLE_POISON_SYSTEM_DIRECTORIES
+#endif
+/* Define to warn for use of native system header directories */
+#ifndef USED_FOR_TARGET
+#undef POISON_BY_DEFAULT
+#endif
+
+
 /* Define if you want all operations on RTL (the basic data structure of the
    optimizer and back end) to be checked for dynamic type safety at runtime.
    This is quite expensive. */
diff --git a/gcc/configure b/gcc/configure
index 2b83acfb0..8bb97578c 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -1023,6 +1023,7 @@ enable_maintainer_mode
 enable_link_mutex
 enable_link_serialization
 enable_version_specific_runtime_libs
+enable_poison_system_directories
 enable_plugin
 enable_host_shared
 enable_libquadmath_support
@@ -1785,6 +1786,8 @@ Optional Features:
   --enable-version-specific-runtime-libs
                           specify that runtime libraries should be installed
                           in a compiler-specific directory
+  --enable-poison-system-directories
+                          warn for use of native system header directories
   --enable-plugin         enable plugin support
   --enable-host-shared    build host code as shared libraries
   --disable-libquadmath-support
@@ -31996,6 +31999,22 @@ if test "${enable_version_specific_runtime_libs+set}" = set; then :
 fi
 
 
+# Check whether --enable-poison-system-directories was given.
+if test "${enable_poison_system_directories+set}" = set; then :
+  enableval=$enable_poison_system_directories;
+else
+  enable_poison_system_directories=no
+fi
+
+if test "x${enable_poison_system_directories}" != "xno"; then
+
+$as_echo "#define ENABLE_POISON_SYSTEM_DIRECTORIES 1" >>confdefs.h
+if test "$enable_poison_system_directories" = "error"; then
+$as_echo "#define POISON_BY_DEFAULT 1" >>confdefs.h
+fi
+
+fi
+
 # Substitute configuration variables
 
 
diff --git a/gcc/configure.ac b/gcc/configure.ac
index daf2a708c..6155b83a7 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -7435,6 +7435,22 @@ AC_ARG_ENABLE(version-specific-runtime-libs,
                 [specify that runtime libraries should be
                  installed in a compiler-specific directory])])
 
+AC_ARG_ENABLE([poison-system-directories],
+             AS_HELP_STRING([--enable-poison-system-directories],
+                            [warn for use of native system header directories (no/yes/error)]),,
+             [enable_poison_system_directories=no])
+AC_MSG_NOTICE([poisoned directories $enable_poison_system_directories])
+if test "x${enable_poison_system_directories}" != "xno"; then
+  AC_MSG_NOTICE([poisoned directories enabled])
+  AC_DEFINE([ENABLE_POISON_SYSTEM_DIRECTORIES],
+           [1],
+           [Define to warn for use of native system header directories])
+  if test $enable_poison_system_directories = "error"; then
+   AC_MSG_NOTICE([poisoned directories are fatal])
+   AC_DEFINE([POISON_BY_DEFAULT], [1], [Define to make poison warnings errors])
+  fi
+fi
+
 # Substitute configuration variables
 AC_SUBST(subdirs)
 AC_SUBST(srcdir)
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index ff6c338be..a8ebfa59a 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -379,6 +379,7 @@ Objective-C and Objective-C++ Dialects}.
 -Wpacked  -Wno-packed-bitfield-compat  -Wpacked-not-aligned  -Wpadded @gol
 -Wparentheses  -Wno-pedantic-ms-format @gol
 -Wpointer-arith  -Wno-pointer-compare  -Wno-pointer-to-int-cast @gol
+-Wno-poison-system-directories @gol
 -Wno-pragmas  -Wno-prio-ctor-dtor  -Wredundant-decls @gol
 -Wrestrict  -Wno-return-local-addr  -Wreturn-type @gol
 -Wno-scalar-storage-order  -Wsequence-point @gol
@@ -8029,6 +8030,14 @@ made up of data only and thus requires no special treatment.  But, for
 most targets, it is made up of code and thus requires the stack to be
 made executable in order for the program to work properly.
 
+@item -Wno-poison-system-directories
+@opindex Wno-poison-system-directories
+Do not warn for @option{-I} or @option{-L} options using system
+directories such as @file{/usr/include} when cross compiling.  This
+option is intended for use in chroot environments when such
+directories contain the correct headers and libraries for the target
+system rather than the host.
+
 @item -Wfloat-equal
 @opindex Wfloat-equal
 @opindex Wno-float-equal
diff --git a/gcc/gcc.cc b/gcc/gcc.cc
index beefde7f6..4e6557b3c 100644
--- a/gcc/gcc.cc
+++ b/gcc/gcc.cc
@@ -1162,6 +1162,8 @@ proper position among the other output files.  */
    "%{fuse-ld=*:-fuse-ld=%*} " LINK_COMPRESS_DEBUG_SPEC \
    "%X %{o*} %{e*} %{N} %{n} %{r}\
     %{s} %{t} %{u*} %{z} %{Z} %{!nostdlib:%{!r:%{!nostartfiles:%S}}} \
+    %{Wno-poison-system-directories:--no-poison-system-directories} \
+    %{Werror=poison-system-directories:--error-poison-system-directories} \
     %{static|no-pie|static-pie:} %@{L*} %(mfwrap) %(link_libgcc) " \
     VTABLE_VERIFICATION_SPEC " " SANITIZER_EARLY_SPEC " %o "" \
     %{fopenacc|fopenmp|%:gt(%{ftree-parallelize-loops=*:%*} 1):\
@@ -1257,8 +1259,11 @@ static const char *cpp_unique_options =
 static const char *cpp_options =
 "%(cpp_unique_options) %1 %{m*} %{std*&ansi&trigraphs} %{W*&pedantic*} %{w}\
  %{f*} %{g*:%{%:debug-level-gt(0):%{g*}\
- %{!fno-working-directory:-fworking-directory}}} %{O*}\
- %{undef} %{save-temps*:-fpch-preprocess}";
+ %{!fno-working-directory:-fworking-directory}}} %{O*}"
+#ifdef POISON_BY_DEFAULT
+ " %{!Wno-error=poison-system-directories:-Werror=poison-system-directories}"
+#endif
+ " %{undef} %{save-temps*:-fpch-preprocess}";
 
 /* Pass -d* flags, possibly modifying -dumpdir, -dumpbase et al.
 
@@ -1287,7 +1292,11 @@ static const char *cc1_options =
  %{coverage:-fprofile-arcs -ftest-coverage}\
  %{fprofile-arcs|fprofile-generate*|coverage:\
    %{!fprofile-update=single:\
-     %{pthread:-fprofile-update=prefer-atomic}}}";
+     %{pthread:-fprofile-update=prefer-atomic}}}"
+#ifdef POISON_BY_DEFAULT
+ " %{!Wno-error=poison-system-directories:-Werror=poison-system-directories}"
+#endif
+  ;
 
 static const char *asm_options =
 "%{-target-help:%:print-asm-header()} "
diff --git a/gcc/incpath.cc b/gcc/incpath.cc
index 622204a38..5ac03c086 100644
--- a/gcc/incpath.cc
+++ b/gcc/incpath.cc
@@ -26,6 +26,7 @@
 #include "intl.h"
 #include "incpath.h"
 #include "cppdefault.h"
+#include "diagnostic-core.h"
 
 /* Microsoft Windows does not natively support inodes.
    VMS has non-numeric inodes.  */
@@ -399,6 +400,26 @@ merge_include_chains (const char *sysroot, cpp_reader *pfile, int verbose)
 	}
       fprintf (stderr, _("End of search list.\n"));
     }
+
+#ifdef ENABLE_POISON_SYSTEM_DIRECTORIES
+  if (flag_poison_system_directories)
+    {
+       struct cpp_dir *p;
+
+       for (p = heads[INC_QUOTE]; p; p = p->next)
+         {
+          if ((!strncmp (p->name, "/usr/include", 12))
+              || (!strncmp (p->name, "/usr/local/include", 18))
+              || (!strncmp (p->name, "/usr/X11R6/include", 18))
+              || (!strncmp (p->name, "/sw/include", 11))
+              || (!strncmp (p->name, "/opt/include", 12)))
+            warning (OPT_Wpoison_system_directories,
+                     "include location \"%s\" is unsafe for "
+                     "cross-compilation",
+                     p->name);
+         }
+    }
+#endif
 }
 
 /* Use given -I paths for #include "..." but not #include <...>, and