Re: [PATCH] kmod-native: Add back-up implementation of be32toh().
From: Lucas De Marchi <hidden>
Date: 2013-09-06 12:55:08
Hi Randy, On Fri, Sep 6, 2013 at 2:59 AM, Randy MacLeod [off-list ref] wrote:
Older hosts may not have the be32toh function defined. Check for this and fall back to checking the endianness and calling bswap_32 directly if needed. This works on both old and new hosts.
I'm fine with adding fallback code, even if I'm surprised with it. However see comments below.
Signed-off-by: Randy MacLeod <redacted>
We don't use s-o-b.
quoted hunk ↗ jump to hunk
--- configure.ac | 1 + libkmod/libkmod-signature.c | 14 +++++++++++++- 2 files changed, 14 insertions(+), 1 deletion(-)diff --git a/configure.ac b/configure.ac index 40e54cf..de2ee49 100644 --- a/configure.ac +++ b/configure.ac@@ -45,6 +45,7 @@ PKG_PROG_PKG_CONFIG AC_CHECK_FUNCS_ONCE(__xstat) AC_CHECK_FUNCS_ONCE([__secure_getenv secure_getenv]) AC_CHECK_FUNCS_ONCE([finit_module]) +AC_CHECK_FUNCS_ONCE([be32toh])
I guess you could use AC_CHECK_DECLS_ONCE so the check below is simpler, since you don't need to care if it's a macro or a function.
quoted hunk ↗ jump to hunk
# dietlibc doesn't have st.st_mtim struct member AC_CHECK_MEMBERS([struct stat.st_mtim], [], [], [#include <sys/stat.h>])diff --git a/libkmod/libkmod-signature.c b/libkmod/libkmod-signature.c index 6237ab7..791d092 100644 --- a/libkmod/libkmod-signature.c +++ b/libkmod/libkmod-signature.c@@ -18,7 +18,7 @@ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ -#include <endian.h> +#include <byteswap.h> #include <stdint.h> #include <stdlib.h> #include <string.h>@@ -26,6 +26,18 @@ #include "libkmod-internal.h" +/* be32toh is usually a macro definend in <endian.h>, but it might be + * a function in some system so check both, and if neither is defined + * then define be32toh (for RHEL 5). + */
by using AC_CHECK_DECLS_ONCE this comment would be gone
+#if !defined(HAVE_BE32TOH) && !defined(be32toh)
as well as the double test.
+#if __BYTE_ORDER == __LITTLE_ENDIAN +#define be32toh(x) __bswap_32 (x)
Is there any reason to include byteswap.h and then end up using the __bswap* variant?
+#else +#define be32toh(x) (x) +#endif +#endif +
Please add this check to the missing.h header. We may want to use this function in more places. Then in this file you just need to include this file. Thanks, Lucas De Marchi