Messages in this thread Patch in this message | | | Subject | [PATCH 2/4] UAPI: Fix endianness conditionals in linux/acct.h | From | David Howells <> | Date | Wed, 06 Mar 2013 20:47:43 +0000 |
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In the UAPI header files, __BIG_ENDIAN and __LITTLE_ENDIAN must be compared against __BYTE_ORDER in preprocessor conditionals where these are exposed to userspace (that is they're not inside __KERNEL__ conditionals).
However, in the main kernel the norm is to check for "defined(__XXX_ENDIAN)" rather than comparing against __BYTE_ORDER and this has incorrectly leaked into the userspace headers.
The definition of ACCT_BYTEORDER in linux/acct.h is wrong in this way. Note that userspace will likely interpret this incorrectly as the big-endian variant on little-endian machines - depending on header inclusion order.
[!!!] NOTE [!!!] This patch may adversely change the userspace API. It might be better to fix the value of ACCT_BYTEORDER.
Signed-off-by: David Howells <dhowells@redhat.com> ---
include/uapi/linux/acct.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/include/uapi/linux/acct.h b/include/uapi/linux/acct.h index 11b6ca3..df2f9a0 100644 --- a/include/uapi/linux/acct.h +++ b/include/uapi/linux/acct.h @@ -107,10 +107,12 @@ struct acct_v3 #define ACORE 0x08 /* ... dumped core */ #define AXSIG 0x10 /* ... was killed by a signal */ -#ifdef __BIG_ENDIAN +#if defined(__BYTE_ORDER) ? __BYTE_ORDER == __BIG_ENDIAN : defined(__BIG_ENDIAN) #define ACCT_BYTEORDER 0x80 /* accounting file is big endian */ -#else +#elif defined(__BYTE_ORDER) ? __BYTE_ORDER == __LITTLE_ENDIAN : defined(__LITTLE_ENDIAN) #define ACCT_BYTEORDER 0x00 /* accounting file is little endian */ +#else +#error unspecified endianness #endif #ifndef __KERNEL__
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