Linux: Use in-tree copy of SO_ constants for !__USE_MISC [BZ #24532]

The kernel changes for a 64-bit time_t on 32-bit architectures
resulted in <asm/socket.h> indirectly including <linux/posix_types.h>.
The latter is not namespace-clean for the POSIX version of
<sys/socket.h>.

This issue has persisted across several Linux releases, so this commit
creates our own copy of the SO_* definitions for !__USE_MISC mode.

The new test socket/tst-socket-consts ensures that the copy is
consistent with the kernel definitions (which vary across
architectures).  The test is tricky to get right because CPPFLAGS
includes include/libc-symbols.h, which in turn defines _GNU_SOURCE
unconditionally.

Tested with build-many-glibcs.py.  I verified that a discrepancy in
the definitions actually results in a failure of the
socket/tst-socket-consts test.

1 files changed, 65 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/tst-socket-consts.py b/sysdeps/unix/sysv/linux/tst-socket-consts.py
new file mode 100644
index 0000000000..ca2634110c
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tst-socket-consts.py
@@ -0,0 +1,65 @@
+#!/usr/bin/python3
+# Test that glibc's sys/socket.h SO_* constants match the kernel's.
+# Copyright (C) 2018-2019 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/>.
+
+import argparse
+import sys
+
+import glibcextract
+
+def main():
+    """The main entry point."""
+    parser = argparse.ArgumentParser(
+        description="Test that glibc's sys/socket.h constants "
+        "match the kernel's.")
+    parser.add_argument('--cc', metavar='CC',
+                        help='C compiler (including options) to use')
+    args = parser.parse_args()
+
+    def check(define):
+        return glibcextract.compare_macro_consts(
+            source_1=define + '#include <sys/socket.h>\n',
+            # Some constants in <asm/socket.h> may depend on the size
+            # of pid_t or time_t.
+            source_2='#include <sys/types.h>\n'
+            '#include <asm/socket.h>\n',
+            cc=args.cc,
+            # We cannot compare all macros because some macros cannot
+            # be expanded as constants, and glibcextract currently is
+            # not able to isolate errors.
+            macro_re='SOL?_.*',
+            # <sys/socket.h> and <asm/socket.h> are not a good match.
+            # Most socket-related constants are not defined in any
+            # UAPI header.  Check only the intersection of the macros
+            # in both headers.  Regular tests ensure that expected
+            # macros for _GNU_SOURCE are present, and the conformance
+            # tests cover most of the other modes.
+            allow_extra_1=True,
+            allow_extra_2=True)
+    # _GNU_SOURCE is defined by include/libc-symbols.h, which is
+    # included by the --cc command.  Defining _ISOMAC does not prevent
+    # that.
+    status = max(
+        check(''),
+        check('#undef _GNU_SOURCE\n'),
+        check('#undef _GNU_SOURCE\n'
+              '#define _POSIX_SOURCE 1\n'))
+    sys.exit(status)
+
+if __name__ == '__main__':
+    main()