Installed header hygiene (BZ#20366): Test of installed headers.

This adds a test to ensure that the problems fixed in the last several
patches do not recur.  Each directory checks the headers that it
installs for two properties: first, each header must be compilable in
isolation, as both C and C++, under a representative combination of
language and library conformance levels; second, there is a blacklist
of identifiers that may not appear in any installed header, currently
consisting of the legacy BSD typedefs.  (There is an exemption for the
headers that define those typedefs, and for the RPC headers.  It may be
necessary to make this more sophisticated if we add more stuff to the
blacklist in the future.)

In order for this test to work correctly, every wrapper header
that actually defines something must guard those definitions with
 #ifndef _ISOMAC.  This is the existing mechanism used by the conform/
tests to tell wrapper headers not to define anything that the public
header wouldn't, and not to use anything from libc-symbols.h.  conform/
only cares for headers that we need to check for standards conformance,
whereas this test applies to *every* header.  (Headers in include/ that
are either installed directly, or are internal-use-only and do *not*
correspond to any installed header, are not affected.)

	* scripts/check-installed-headers.sh: New script.
	* Rules: In each directory that defines header files to be installed,
	run check-installed-headers.sh on them as a special test.
	* Makefile: Likewise for the headers installed at top level.

	* include/aliases.h, include/alloca.h, include/argz.h
	* include/arpa/nameser.h, include/arpa/nameser_compat.h
	* include/elf.h, include/envz.h, include/err.h
	* include/execinfo.h, include/fpu_control.h, include/getopt.h
	* include/gshadow.h, include/ifaddrs.h, include/libintl.h
	* include/link.h, include/malloc.h, include/mcheck.h
	* include/mntent.h, include/netinet/ether.h
	* include/nss.h, include/obstack.h, include/printf.h
	* include/pty.h, include/resolv.h, include/rpc/auth.h
	* include/rpc/auth_des.h, include/rpc/auth_unix.h
	* include/rpc/clnt.h, include/rpc/des_crypt.h
	* include/rpc/key_prot.h, include/rpc/netdb.h
	* include/rpc/pmap_clnt.h, include/rpc/pmap_prot.h
	* include/rpc/pmap_rmt.h, include/rpc/rpc.h
	* include/rpc/rpc_msg.h, include/rpc/svc.h
	* include/rpc/svc_auth.h, include/rpc/xdr.h
	* include/rpcsvc/nis_callback.h, include/rpcsvc/nislib.h
	* include/rpcsvc/yp.h, include/rpcsvc/ypclnt.h
	* include/rpcsvc/ypupd.h, include/shadow.h
	* include/stdio_ext.h, include/sys/epoll.h
	* include/sys/file.h, include/sys/gmon.h, include/sys/ioctl.h
	* include/sys/prctl.h, include/sys/profil.h
	* include/sys/statfs.h, include/sys/sysctl.h
	* include/sys/sysinfo.h, include/ttyent.h, include/utmp.h
	* sysdeps/arm/nacl/include/bits/setjmp.h
	* sysdeps/mips/include/sys/asm.h
	* sysdeps/unix/sysv/linux/include/sys/sysinfo.h
	* sysdeps/unix/sysv/linux/include/sys/timex.h
	* sysdeps/x86/fpu/include/bits/fenv.h:
	Add #ifndef _ISOMAC guard around internal declarations.
	Add multiple-inclusion guard if not already present.

1 files changed, 146 insertions, 0 deletions

diff --git a/scripts/check-installed-headers.sh b/scripts/check-installed-headers.sh
new file mode 100644
index 0000000000..7fbc725c0f
--- /dev/null
+++ b/scripts/check-installed-headers.sh
@@ -0,0 +1,146 @@
+#! /bin/sh
+# Copyright (C) 2016 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
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# The GNU C Library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with the GNU C Library; if not, see
+# <http://www.gnu.org/licenses/>.
+
+# Check installed headers for cleanliness.  For each header, confirm
+# that it's possible to compile a file that includes that header and
+# does nothing else, in several different compilation modes.  Also,
+# scan the header for a set of obsolete typedefs that should no longer
+# appear.
+
+# These compilation switches assume GCC or compatible, which is probably
+# fine since we also assume that when _building_ glibc.
+c_modes="-std=c89 -std=gnu89 -std=c11 -std=gnu11"
+cxx_modes="-std=c++98 -std=gnu++98 -std=c++11 -std=gnu++11"
+
+# An exhaustive test of feature selection macros would take far too long.
+# These are probably the most commonly used three.
+lib_modes="-D_DEFAULT_SOURCE=1 -D_GNU_SOURCE=1 -D_XOPEN_SOURCE=700"
+
+# sys/types.h+bits/types.h have to define the obsolete types.
+# rpc(svc)/* have the obsolete types too deeply embedded in their API
+# to remove.
+skip_obsolete_type_check='*/sys/types.h|*/bits/types.h|*/rpc/*|*/rpcsvc/*'
+obsolete_type_re=\
+'\<((__)?(quad_t|u(short|int|long|_(char|short|int([0-9]+_t)?|long|quad_t))))\>'
+
+if [ $# -lt 3 ]; then
+    echo "usage: $0 c|c++ \"compile command\" header header header..." >&2
+    exit 2
+fi
+case "$1" in
+    (c)
+        lang_modes="$c_modes"
+        cih_test_c=$(mktemp ${TMPDIR-/tmp}/cih_test_XXXXXX.c)
+        already="$skip_obsolete_type_check"
+    ;;
+    (c++)
+        lang_modes="$cxx_modes"
+        cih_test_c=$(mktemp ${TMPDIR-/tmp}/cih_test_XXXXXX.cc)
+        # The obsolete-type check can be skipped for C++; it is
+        # sufficient to do it for C.
+        already="*"
+    ;;
+    (*)
+        echo "usage: $0 c|c++ \"compile command\" header header header..." >&2
+        exit 2;;
+esac
+shift
+cc_cmd="$1"
+shift
+trap "rm -f '$cih_test_c'" 0
+
+failed=0
+is_x86_64=unknown
+for header in "$@"; do
+    # Skip various headers for which this test gets a false failure.
+    case "$header" in
+        # bits/* are not meant to be included directly and usually #error
+        # out if you try it.
+        # regexp.h is a stub containing only an #error.
+        # Sun RPC's .x files are traditionally installed in
+        # $prefix/include/rpcsvc, but they are not C header files.
+        (bits/* | regexp.h | rpcsvc/*.x)
+            continue;;
+
+        # sys/elf.h and sys/vm86.h are "unsupported on x86-64" and
+        # #error out on that target.
+        (sys/elf.h | sys/vm86.h)
+            case "$is_x86_64" in
+                (yes) continue;;
+                (no)  ;;
+                (unknown)
+                    cat >"$cih_test_c" <<EOF
+#if defined __x86_64__ && __x86_64__
+#error "is x86-64"
+#endif
+EOF
+                    if $cc_cmd -fsyntax-only "$cih_test_c" > /dev/null 2>&1
+                    then
+                        is_x86_64=no
+                    else
+                        is_x86_64=yes
+                        continue
+                    fi
+                ;;
+            esac
+    esac
+
+    echo :: "$header"
+    for lang_mode in "" $lang_modes; do
+        for lib_mode in "" $lib_modes; do
+            echo :::: $lang_mode $lib_mode
+            if [ -z "$lib_mode" ]; then
+                expanded_lib_mode='/* default library mode */'
+            else
+                expanded_lib_mode=$(echo : $lib_mode | \
+                    sed 's/^: -D/#define /; s/=/ /')
+            fi
+            cat >"$cih_test_c" <<EOF
+/* These macros may have been defined on the command line.  They are
+   inappropriate for this test.  */
+#undef _LIBC
+#undef _GNU_SOURCE
+#undef _REENTRANT
+/* The library mode is selected here rather than on the command line to
+   ensure that this selection wins. */
+$expanded_lib_mode
+#include <$header>
+int avoid_empty_translation_unit;
+EOF
+            if $cc_cmd -fsyntax-only $lang_mode "$cih_test_c" 2>&1
+            then
+                includes=$($cc_cmd -fsyntax-only -H $lang_mode \
+                              "$cih_test_c" 2>&1 | sed -ne 's/^[.][.]* //p')
+                for h in $includes; do
+                    # Don't repeat work.
+                    eval 'case "$h" in ('"$already"') continue;; esac'
+
+                    if grep -qE "$obsolete_type_re" "$h"; then
+                        echo "*** Obsolete types detected:"
+                        grep -HE "$obsolete_type_re" "$h"
+                        failed=1
+                    fi
+                    already="$already|$h"
+                done
+            else
+                failed=1
+            fi
+        done
+    done
+done
+exit $failed