[PATCH for-4.15] autoconf: check endian.h include path

Roger Pau Monne posted 1 patch 3 years, 1 month ago
Test gitlab-ci failed
Patches applied successfully (tree, apply log)
git fetch https://gitlab.com/xen-project/patchew/xen tags/patchew/20210204093833.91190-1-roger.pau@citrix.com
m4/header.m4                                      | 13 +++++++++++++
tools/configure.ac                                |  3 +++
tools/libs/guest/xg_dom_decompress_unsafe_lzo1x.c |  2 +-
tools/libs/guest/xg_dom_decompress_unsafe_xz.c    |  2 +-
tools/libs/guest/xg_dom_decompress_unsafe_zstd.c  |  2 +-
tools/xenstore/include/xenstore_state.h           |  6 +-----
6 files changed, 20 insertions(+), 8 deletions(-)
create mode 100644 m4/header.m4
[PATCH for-4.15] autoconf: check endian.h include path
Posted by Roger Pau Monne 3 years, 1 month ago
Introduce an autoconf macro to check for the include path of certain
headers that can be different between OSes.

Use such macro to find the correct path for the endian.h header, and
modify the users of endian.h to use the output of such check.

Suggested-by: Ian Jackson <iwj@xenproject.org>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
Please re-run autogen after applying.

The biggest risk for this would be some kind of configure or build
failure, and we should be able to catch it in either osstest or the
gitlab build tests.
---
 m4/header.m4                                      | 13 +++++++++++++
 tools/configure.ac                                |  3 +++
 tools/libs/guest/xg_dom_decompress_unsafe_lzo1x.c |  2 +-
 tools/libs/guest/xg_dom_decompress_unsafe_xz.c    |  2 +-
 tools/libs/guest/xg_dom_decompress_unsafe_zstd.c  |  2 +-
 tools/xenstore/include/xenstore_state.h           |  6 +-----
 6 files changed, 20 insertions(+), 8 deletions(-)
 create mode 100644 m4/header.m4

diff --git a/m4/header.m4 b/m4/header.m4
new file mode 100644
index 0000000000..81d1d65194
--- /dev/null
+++ b/m4/header.m4
@@ -0,0 +1,13 @@
+AC_DEFUN([AX_FIND_HEADER], [
+ax_found=0
+m4_foreach_w([header], $2, [
+    AS_IF([test "$ax_found" = "0"], [
+        AC_CHECK_HEADER(header, [
+            AC_DEFINE($1, [<header>], [Header path for $1])
+            ax_found=1])
+    ])
+])
+AS_IF([test "$ax_found" = "0"], [
+    AC_MSG_ERROR([No header found from list $2])
+])
+])
diff --git a/tools/configure.ac b/tools/configure.ac
index 5b328700e0..3a3e7b4b2b 100644
--- a/tools/configure.ac
+++ b/tools/configure.ac
@@ -74,6 +74,7 @@ m4_include([../m4/ax_compare_version.m4])
 m4_include([../m4/paths.m4])
 m4_include([../m4/systemd.m4])
 m4_include([../m4/golang.m4])
+m4_include([../m4/header.m4])
 
 AX_XEN_EXPAND_CONFIG()
 
@@ -517,4 +518,6 @@ AC_ARG_ENABLE([pvshim],
 ])
 AC_SUBST(pvshim)
 
+AX_FIND_HEADER([INCLUDE_ENDIAN_H], [endian.h sys/endian.h])
+
 AC_OUTPUT()
diff --git a/tools/libs/guest/xg_dom_decompress_unsafe_lzo1x.c b/tools/libs/guest/xg_dom_decompress_unsafe_lzo1x.c
index a4f8ebd42d..e58c1b95ed 100644
--- a/tools/libs/guest/xg_dom_decompress_unsafe_lzo1x.c
+++ b/tools/libs/guest/xg_dom_decompress_unsafe_lzo1x.c
@@ -1,7 +1,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <inttypes.h>
-#include <endian.h>
+#include INCLUDE_ENDIAN_H
 #include <stdint.h>
 
 #include "xg_private.h"
diff --git a/tools/libs/guest/xg_dom_decompress_unsafe_xz.c b/tools/libs/guest/xg_dom_decompress_unsafe_xz.c
index ff6824b38d..fc48198741 100644
--- a/tools/libs/guest/xg_dom_decompress_unsafe_xz.c
+++ b/tools/libs/guest/xg_dom_decompress_unsafe_xz.c
@@ -1,5 +1,5 @@
 #include <stdio.h>
-#include <endian.h>
+#include INCLUDE_ENDIAN_H
 #include <stdlib.h>
 #include <stddef.h>
 #include <stdint.h>
diff --git a/tools/libs/guest/xg_dom_decompress_unsafe_zstd.c b/tools/libs/guest/xg_dom_decompress_unsafe_zstd.c
index 52558d2ffc..01eafaaaa6 100644
--- a/tools/libs/guest/xg_dom_decompress_unsafe_zstd.c
+++ b/tools/libs/guest/xg_dom_decompress_unsafe_zstd.c
@@ -1,5 +1,5 @@
 #include <stdio.h>
-#include <endian.h>
+#include INCLUDE_ENDIAN_H
 #include <stdlib.h>
 #include <stddef.h>
 #include <stdint.h>
diff --git a/tools/xenstore/include/xenstore_state.h b/tools/xenstore/include/xenstore_state.h
index f7e4da2b2c..ae0d053c8f 100644
--- a/tools/xenstore/include/xenstore_state.h
+++ b/tools/xenstore/include/xenstore_state.h
@@ -21,11 +21,7 @@
 #ifndef XENSTORE_STATE_H
 #define XENSTORE_STATE_H
 
-#if defined(__FreeBSD__) || defined(__NetBSD__)
-#include <sys/endian.h>
-#else
-#include <endian.h>
-#endif
+#include INCLUDE_ENDIAN_H
 #include <sys/types.h>
 
 #ifndef htobe32
-- 
2.29.2


Re: [PATCH for-4.15] autoconf: check endian.h include path
Posted by Jan Beulich 3 years, 1 month ago
On 04.02.2021 10:38, Roger Pau Monne wrote:
> --- a/tools/configure.ac
> +++ b/tools/configure.ac
> @@ -74,6 +74,7 @@ m4_include([../m4/ax_compare_version.m4])
>  m4_include([../m4/paths.m4])
>  m4_include([../m4/systemd.m4])
>  m4_include([../m4/golang.m4])
> +m4_include([../m4/header.m4])
>  
>  AX_XEN_EXPAND_CONFIG()
>  
> @@ -517,4 +518,6 @@ AC_ARG_ENABLE([pvshim],
>  ])
>  AC_SUBST(pvshim)
>  
> +AX_FIND_HEADER([INCLUDE_ENDIAN_H], [endian.h sys/endian.h])

Instead of a new macro, can't you use AC_CHECK_HEADERS()?

I'm also not certain about the order of checks - what if both
exist?

Jan

Re: [PATCH for-4.15] autoconf: check endian.h include path
Posted by Roger Pau Monné 3 years, 1 month ago
On Thu, Feb 04, 2021 at 10:46:58AM +0100, Jan Beulich wrote:
> On 04.02.2021 10:38, Roger Pau Monne wrote:
> > --- a/tools/configure.ac
> > +++ b/tools/configure.ac
> > @@ -74,6 +74,7 @@ m4_include([../m4/ax_compare_version.m4])
> >  m4_include([../m4/paths.m4])
> >  m4_include([../m4/systemd.m4])
> >  m4_include([../m4/golang.m4])
> > +m4_include([../m4/header.m4])
> >  
> >  AX_XEN_EXPAND_CONFIG()
> >  
> > @@ -517,4 +518,6 @@ AC_ARG_ENABLE([pvshim],
> >  ])
> >  AC_SUBST(pvshim)
> >  
> > +AX_FIND_HEADER([INCLUDE_ENDIAN_H], [endian.h sys/endian.h])
> 
> Instead of a new macro, can't you use AC_CHECK_HEADERS()?

AC_CHECK_HEADERS doesn't do what we want here: it will instead produce
a HAVE_header-file define for each header on the list that's present,
and the action-if-found doesn't get passed the path of the found
header according to the documentation.

Here I want the variable to be set to the include path of the first
header on the list that's present on the system.

> I'm also not certain about the order of checks - what if both
> exist?

With my macro the first one will be picked.

Thanks, Roger.

Re: [PATCH for-4.15] autoconf: check endian.h include path
Posted by Jan Beulich 3 years, 1 month ago
On 04.02.2021 10:59, Roger Pau Monné wrote:
> On Thu, Feb 04, 2021 at 10:46:58AM +0100, Jan Beulich wrote:
>> On 04.02.2021 10:38, Roger Pau Monne wrote:
>>> --- a/tools/configure.ac
>>> +++ b/tools/configure.ac
>>> @@ -74,6 +74,7 @@ m4_include([../m4/ax_compare_version.m4])
>>>  m4_include([../m4/paths.m4])
>>>  m4_include([../m4/systemd.m4])
>>>  m4_include([../m4/golang.m4])
>>> +m4_include([../m4/header.m4])
>>>  
>>>  AX_XEN_EXPAND_CONFIG()
>>>  
>>> @@ -517,4 +518,6 @@ AC_ARG_ENABLE([pvshim],
>>>  ])
>>>  AC_SUBST(pvshim)
>>>  
>>> +AX_FIND_HEADER([INCLUDE_ENDIAN_H], [endian.h sys/endian.h])
>>
>> Instead of a new macro, can't you use AC_CHECK_HEADERS()?
> 
> AC_CHECK_HEADERS doesn't do what we want here: it will instead produce
> a HAVE_header-file define for each header on the list that's present,
> and the action-if-found doesn't get passed the path of the found
> header according to the documentation.
> 
> Here I want the variable to be set to the include path of the first
> header on the list that's present on the system.

I was thinking of

#if defined(HAVE_SYS_ENDIAN_H)
# include <sys/endian.h>
#elif defined(HAVE_ENDIAN_H)
# include <endian.h>
#else
# error ...
#endif

>> I'm also not certain about the order of checks - what if both
>> exist?
> 
> With my macro the first one will be picked.

And which one is to be the first one? IOW how likely is it that
on a system having both the first one is what we're after vs
the second one?

Jan

Re: [PATCH for-4.15] autoconf: check endian.h include path
Posted by Ian Jackson 3 years, 1 month ago
Roger Pau Monne writes ("[PATCH for-4.15] autoconf: check endian.h include path"):
> Introduce an autoconf macro to check for the include path of certain
> headers that can be different between OSes.
> 
> Use such macro to find the correct path for the endian.h header, and
> modify the users of endian.h to use the output of such check.
> 
> Suggested-by: Ian Jackson <iwj@xenproject.org>
> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>

Reviewed-by: Ian Jackson <iwj@xenproject.org>

> Please re-run autogen after applying.
> 
> The biggest risk for this would be some kind of configure or build
> failure, and we should be able to catch it in either osstest or the
> gitlab build tests.

Thanks.  I agree.

Release-Acked-by: Ian Jackson <iwj@xenproject.org>