Fix sys/socket.h namespace issues from sys/uio.h inclusion (bug 21426)

[Joseph Myers <joseph at codesourcery dot com>]

sys/socket.h includes sys/uio.h to get the definition of the iovec
structure.

POSIX allows sys/socket.h to make all sys/uio.h symbols visible.
However, all of sys/uio.h is XSI-shaded, so for non-XSI POSIX this
results in conformtest failures (for sys/socket.h and other headers
that include it):

    Namespace violation: "UIO_MAXIOV"
    Namespace violation: "readv"
    Namespace violation: "writev"

Now, there is some ambiguity in POSIX about what namespace
reservations apply in this case - see
http://austingroupbugs.net/view.php?id=1127 - but glibc convention
would still avoid declaring readv and writev, for example, for feature
test macros that don't include them (if only headers from the relevant
standard are included), even if such declarations are permitted, so
there is a bug here according to glibc conventions.

This patch moves the struct iovec definition to a new
bits/types/struct_iovec.h header and includes that from sys/socket.h
instead of including the whole of sys/uio.h.  This fixes the namespace
issue; however, three files in glibc that were relying on the implicit
inclusion needed to be updated to include sys/uio.h explicitly.  So
there is a question of whether sys/socket.h should continue to include
sys/uio.h under some conditions, such as __USE_XOPEN or __USE_MISC or
__USE_XOPEN || __USE_MISC, for greater compatibility with code that
(wrongly) expects this optional inclusion to be present there.  (I
think the three affected files in glibc should still have explicit
sys/uio.h inclusions added in any case, however.)

Tested for x86_64.

2017-04-25  Joseph Myers  <joseph@codesourcery.com>

	[BZ #21426]
	* misc/bits/types/struct_iovec.h: New file.
	* misc/Makefile (headers): Add bits/types/struct_iovec.h.
	* include/bits/types/struct_iovec.h: New file.
	* bits/uio.h (struct iovec): Replace by inclusion of
	<bits/types/struct_iovec.h>.
	* sysdeps/unix/sysv/linux/bits/uio.h (struct iovec): Likewise.
	* socket/sys/socket.h: Include <bits/types/struct_iovec.h> instead
	of <sys/uio.h>.
	* nptl/tst-cancel4.c: Include <sys/uio.h>
	* posix/test-errno.c: Likewise.
	* support/resolv_test.c: Likewise.
	* conform/Makefile (test-xfail-POSIX2008/arpa/inet.h/conform):
	Remove.
	(test-xfail-POSIX2008/netdb.h/conform): Likewise.
	(test-xfail-POSIX2008/netinet/in.h/conform): Likewise.
	(test-xfail-POSIX2008/sys/socket.h/conform): Likewise.

diff --git a/bits/uio.h b/bits/uio.h
index def26df..96a3a71 100644
--- a/bits/uio.h
+++ b/bits/uio.h
@@ -20,12 +20,4 @@
 #endif
 
 
-/* `struct iovec' -- Structure describing a section of memory.  */
-
-struct iovec
-{
-  /* Starting address.  */
-  __ptr_t iov_base;
-  /* Length in bytes.  */
-  size_t iov_len;
-};
+#include <bits/types/struct_iovec.h>
diff --git a/conform/Makefile b/conform/Makefile
index 9638dda..19404fd 100644
--- a/conform/Makefile
+++ b/conform/Makefile
@@ -180,11 +180,7 @@ test-xfail-XOPEN2K/semaphore.h/conform = yes
 test-xfail-XOPEN2K/signal.h/conform = yes
 test-xfail-XOPEN2K/sys/wait.h/conform = yes
 test-xfail-XOPEN2K/ucontext.h/conform = yes
-test-xfail-POSIX2008/arpa/inet.h/conform = yes
-test-xfail-POSIX2008/netdb.h/conform = yes
-test-xfail-POSIX2008/netinet/in.h/conform = yes
 test-xfail-POSIX2008/signal.h/conform = yes
-test-xfail-POSIX2008/sys/socket.h/conform = yes
 test-xfail-POSIX2008/sys/wait.h/conform = yes
 test-xfail-XOPEN2K8/signal.h/conform = yes
 test-xfail-XOPEN2K8/sys/wait.h/conform = yes
diff --git a/include/bits/types/struct_iovec.h b/include/bits/types/struct_iovec.h
new file mode 100644
index 0000000..116a247
--- /dev/null
+++ b/include/bits/types/struct_iovec.h
@@ -0,0 +1 @@
+#include "../../misc/bits/types/struct_iovec.h"
diff --git a/misc/Makefile b/misc/Makefile
index ed988c3..622da67 100644
--- a/misc/Makefile
+++ b/misc/Makefile
@@ -35,7 +35,7 @@ headers	:= sys/uio.h bits/uio.h sys/ioctl.h bits/ioctls.h bits/ioctl-types.h \
 	   syslog.h sys/syslog.h \
 	   bits/syslog.h bits/syslog-ldbl.h bits/syslog-path.h bits/error.h \
 	   bits/select2.h bits/hwcap.h sys/auxv.h \
-	   sys/sysmacros.h bits/sysmacros.h
+	   sys/sysmacros.h bits/sysmacros.h bits/types/struct_iovec.h
 
 routines := brk sbrk sstk ioctl \
 	    readv writev preadv preadv64 pwritev pwritev64 \
diff --git a/misc/bits/types/struct_iovec.h b/misc/bits/types/struct_iovec.h
new file mode 100644
index 0000000..bd625a3
--- /dev/null
+++ b/misc/bits/types/struct_iovec.h
@@ -0,0 +1,32 @@
+/* Define struct iovec.
+   Copyright (C) 1996-2017 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/>.  */
+
+#ifndef __iovec_defined
+#define __iovec_defined 1
+
+#define __need_size_t
+#include <stddef.h>
+
+/* Structure for scatter/gather I/O.  */
+struct iovec
+  {
+    void *iov_base;	/* Pointer to data.  */
+    size_t iov_len;	/* Length of data.  */
+  };
+
+#endif
diff --git a/nptl/tst-cancel4.c b/nptl/tst-cancel4.c
index a68a3ef..590ce0a 100644
--- a/nptl/tst-cancel4.c
+++ b/nptl/tst-cancel4.c
@@ -38,6 +38,7 @@
 #include <sys/poll.h>
 #include <sys/wait.h>
 #include <sys/stat.h>
+#include <sys/uio.h>
 
 
 /* Since STREAMS are not supported in the standard Linux kernel and
diff --git a/posix/test-errno.c b/posix/test-errno.c
index c2bfd8a..6aa297f 100644
--- a/posix/test-errno.c
+++ b/posix/test-errno.c
@@ -31,6 +31,7 @@
 #include <sys/types.h>
 #include <sys/statfs.h>
 #include <sys/mman.h>
+#include <sys/uio.h>
 #include <unistd.h>
 #include <netinet/in.h>
 
diff --git a/socket/sys/socket.h b/socket/sys/socket.h
index 609a08d..7af4109 100644
--- a/socket/sys/socket.h
+++ b/socket/sys/socket.h
@@ -23,7 +23,7 @@
 
 __BEGIN_DECLS
 
-#include <sys/uio.h>
+#include <bits/types/struct_iovec.h>
 #define	__need_size_t
 #include <stddef.h>
 #ifdef __USE_GNU
diff --git a/support/resolv_test.c b/support/resolv_test.c
index 5c5a463..050cd71 100644
--- a/support/resolv_test.c
+++ b/support/resolv_test.c
@@ -33,6 +33,7 @@
 #include <support/xsocket.h>
 #include <support/xthread.h>
 #include <support/xunistd.h>
+#include <sys/uio.h>
 #include <unistd.h>
 
 /* Response builder.  */
diff --git a/sysdeps/unix/sysv/linux/bits/uio.h b/sysdeps/unix/sysv/linux/bits/uio.h
index 065a5d5..1583f04 100644
--- a/sysdeps/unix/sysv/linux/bits/uio.h
+++ b/sysdeps/unix/sysv/linux/bits/uio.h
@@ -39,12 +39,7 @@
 #define UIO_MAXIOV	1024
 
 
-/* Structure for scatter/gather I/O.  */
-struct iovec
-  {
-    void *iov_base;	/* Pointer to data.  */
-    size_t iov_len;	/* Length of data.  */
-  };
+#include <bits/types/struct_iovec.h>
 
 #endif
 

-- 
Joseph S. Myers
joseph@codesourcery.com