Re: [PATCH] Allow building if libsanitizer on RHEL5 (i.e. with 2.6.18-ish kernel headers)

[Richard Biener <richard dot guenther at gmail dot com>]

On Fri, Dec 6, 2013 at 1:43 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> Hi!
>
> Here is an alternative version of the patch I've posted earlier to allow
> building libsanitizer on 2.6.18-ish kernel headers, this time by adding
> 5 tiny kernel header wrappers.
> The only drawback of this are warnings like:
> ../../../../libsanitizer/include/linux/aio_abi.h:2:2: warning: #include_next is a GCC extension [enabled by default]
> (and generally just on the two source files that include these problematic
> kernel headers, so about 10 warnings total).
> We could avoid that by not building with -pedantic, or by using
> -isystem instead of -I for the libsanitizer/include headers (which has
> drawback that we wouldn't get warnings for stuff in
> libsanitizer/include/sanitizer/ headers), or these could live in
> some other directory, say libsanitizer/include/wrappers/linux/*.h
> and we would add -isystem $(top_srcdir)/include/wrappers/.
>
> Note that testing still shows some issues, e.g. because the
> kThreadDescriptorSize change has not been applied.  But it at least builds
> and for many tests works.

What's wrong with just copying the kernel headers 1:1?  ISTR that is what
kernel folks recommend if you use kernel APIs that don't have a glibc
correspondent.

Of course you then need runtime checks on whether the running kernel
supports the API.

Richard.

> 2013-12-06  Jakub Jelinek  <jakub@redhat.com>
>
>         * include/linux/aio_abi.h: New header.
>         * include/linux/mroute.h: New header.
>         * include/linux/mroute6.h: New header.
>         * include/linux/perf_event.h: New header.
>         * include/linux/types.h: New header.
>
> --- libsanitizer/include/linux/aio_abi.h.jj     2013-12-06 06:02:29.000000000 -0500
> +++ libsanitizer/include/linux/aio_abi.h        2013-12-06 06:03:11.000000000 -0500
> @@ -0,0 +1,7 @@
> +#include <linux/version.h>
> +#include_next <linux/aio_abi.h>
> +/* IOCB_CMD_PREADV/PWRITEV has been added in 2.6.19 */
> +#if LINUX_VERSION_CODE < 132627
> +#define IOCB_CMD_PREADV 7
> +#define IOCB_CMD_PWRITEV 8
> +#endif
> --- libsanitizer/include/linux/mroute.h.jj      2013-12-06 06:14:30.000000000 -0500
> +++ libsanitizer/include/linux/mroute.h 2013-12-06 06:10:09.000000000 -0500
> @@ -0,0 +1,8 @@
> +#include <linux/version.h>
> +/* <linux/mroute.h> before 2.6.26 included <linux/in.h>
> +   which clashes with userspace headers.  */
> +#if LINUX_VERSION_CODE < 132634
> +#define _LINUX_IN_H
> +#include <linux/types.h>
> +#endif
> +#include_next <linux/mroute.h>
> --- libsanitizer/include/linux/mroute6.h.jj     2013-12-06 03:58:19.000000000 -0500
> +++ libsanitizer/include/linux/mroute6.h        2013-12-06 06:13:59.000000000 -0500
> @@ -0,0 +1,5 @@
> +#include <linux/version.h>
> +/* <linux/mroute6.h> has been added in 2.6.26 */
> +#if LINUX_VERSION_CODE >= 132634
> +#include_next <linux/mroute6.h>
> +#endif
> --- libsanitizer/include/linux/perf_event.h.jj  2013-12-06 03:58:01.000000000 -0500
> +++ libsanitizer/include/linux/perf_event.h     2013-12-06 05:59:16.000000000 -0500
> @@ -0,0 +1,7 @@
> +#include <linux/version.h>
> +/* <linux/perf_event.h> has been added in 2.6.32 */
> +#if LINUX_VERSION_CODE >= 132640
> +#include_next <linux/perf_event.h>
> +#else
> +#define perf_event_attr __sanitizer_perf_event_attr
> +#endif
> --- libsanitizer/include/linux/types.h.jj       2013-12-06 03:57:37.000000000 -0500
> +++ libsanitizer/include/linux/types.h  2013-12-06 03:57:33.000000000 -0500
> @@ -0,0 +1,12 @@
> +#ifndef LINUX_TYPES_WRAPPER_H
> +#define LINUX_TYPES_WRAPPER_H
> +
> +/* Before
> +   https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/include/linux/types.h?id=6c7c6afbb8c0e60d32a563cae7c6889211e9d9d8
> +   linux/types.h conflicted with sys/ustat.h.  Work around it.  */
> +
> +#define ustat __asan_bad_ustat
> +#include_next <linux/types.h>
> +#undef ustat
> +
> +#endif
>
>         Jakub