From f7c26bbbf0496d179f5e71107fe6cf1320b25901 Mon Sep 17 00:00:00 2001
From: Khem Raj <raj.khem@gmail.com>
Date: Thu, 23 Jan 2025 17:12:51 -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: Inappropriate [OE configuration]
Signed-off-by: Mark Hatle <mark.hatle@windriver.com>
Signed-off-by: sunil dora <sunilkumar.dora@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          | 12 ++++++++++--
 gcc/incpath.cc      | 25 +++++++++++++++++++++++++
 7 files changed, 93 insertions(+), 2 deletions(-)

diff --git a/gcc/common.opt b/gcc/common.opt
index e3fa0dacec4..bea1adc0940 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -729,6 +729,10 @@ 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 a79c51adb2b..8a531ed591c 100644
--- a/gcc/config.in
+++ b/gcc/config.in
@@ -249,6 +249,16 @@
 #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 16965953f05..0f4a5d52c30 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -1051,6 +1051,7 @@ enable_maintainer_mode
 enable_link_mutex
 enable_link_serialization
 enable_version_specific_runtime_libs
+enable_poison_system_directories
 enable_plugin
 enable_host_shared
 enable_host_pie
@@ -1828,6 +1829,8 @@ 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
   --enable-host-pie       build host code as PIE
@@ -34027,6 +34030,22 @@ 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 9f67e62950a..b0e3615e5aa 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -7502,6 +7502,22 @@ 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 c2e1bf8031b..d33e2042f38 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -405,6 +405,7 @@ Objective-C and Objective-C++ Dialects}.
 -Wpacked  -Wno-packed-bitfield-compat  -Wpacked-not-aligned  -Wpadded
 -Wparentheses  -Wno-pedantic-ms-format
 -Wpointer-arith  -Wno-pointer-compare  -Wno-pointer-to-int-cast
+-Wno-poison-system-directories
 -Wno-pragmas  -Wno-pragma-once-outside-header  -Wno-prio-ctor-dtor
 -Wno-psabi
 -Wredundant-decls  -Wrestrict
@@ -10727,6 +10728,14 @@ an error. @option{Wint-to-pointer-cast} is enabled by default.
 Suppress warnings from casts from a pointer to an integer type of a
 different size.
 
+@opindex Wno-poison-system-directories
+@item -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.
+
 @opindex Winvalid-pch
 @opindex Wno-invalid-pch
 @item -Winvalid-pch
diff --git a/gcc/gcc.cc b/gcc/gcc.cc
index 4fd87f2c4a1..79d4920a047 100644
--- a/gcc/gcc.cc
+++ b/gcc/gcc.cc
@@ -909,6 +909,12 @@ proper position among the other output files.  */
 #define ASM_MAP ""
 #endif
 
+#ifdef POISON_BY_DEFAULT
+#define POISON_IS_ERROR " -Werror=poison-system-directories"
+#else
+#define POISON_IS_ERROR
+#endif
+
 /* Assembler options for compressed debug sections.  */
 #if HAVE_LD_COMPRESS_DEBUG == 0
 /* Reject if the linker cannot write compressed debug sections.  */
@@ -1166,6 +1172,8 @@ 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*} %(link_libgcc) " \
     VTABLE_VERIFICATION_SPEC " " SANITIZER_EARLY_SPEC " %o "" \
     %{fopenacc|fopenmp|%:gt(%{ftree-parallelize-loops=*:%*} 1):\
@@ -1268,7 +1276,7 @@ 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}";
+ %{undef} %{save-temps*:-fpch-preprocess}" POISON_IS_ERROR;
 
 /* Pass -d* flags, possibly modifying -dumpdir, -dumpbase et al.
 
@@ -1297,7 +1305,7 @@ static const char *cc1_options =
  %{coverage:-fprofile-arcs -ftest-coverage}\
  %{fprofile-arcs|fcondition-coverage|fpath-coverage|fprofile-generate*|coverage:\
    %{!fprofile-update=single:\
-     %{pthread:-fprofile-update=prefer-atomic}}}";
+     %{pthread:-fprofile-update=prefer-atomic}}}" POISON_IS_ERROR;
 
 static const char *asm_options =
 "%{-target-help:%:print-asm-header()} "
diff --git a/gcc/incpath.cc b/gcc/incpath.cc
index c1bbfd3872a..2cdbebc4c50 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.  */
@@ -273,6 +274,10 @@ remove_duplicates (cpp_reader *pfile, struct cpp_dir *head,
 			     cur->name, xstrerror (errno));
 	      reason = REASON_NOENT;
 	    }
+#ifdef ENABLE_POISON_SYSTEM_DIRECTORIES
+	  pcur = &cur->next;
+	  continue;
+#endif
 	}
       else if (!S_ISDIR (st.st_mode))
 	cpp_error_with_line (pfile, CPP_DL_WARNING, 0, 0,
@@ -411,6 +416,26 @@ merge_include_chains (const char *sysroot, cpp_reader *pfile, int verbose)
 	  fprintf (stderr, _("End of #embed 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
