[Buildroot] [PATCH] package/ibm-sw-tpm2: re-fix build with uClibc-ng and older glibcs

Vincent Fazio vfazio at xes-inc.com
Mon Aug 24 13:28:11 UTC 2020


Thomas,

On 8/23/20 4:18 PM, Thomas Petazzoni wrote:
> In commit 26e37cef1627faa1f5ab8935482e2b2bc3465c33, we started using
> __WORDSIZE to get the size of longs on the given architecture, in
> order to support all CPU architectures.
> 
> Unfortunately, __WORDSIZE is not enabled in musl, so in
> 19bd08900448aa45b506320ad2ab912f789e6e5e, we switched to using
> LONG_BIT instead of __WORDSIZE.
> 
> However, LONG_BIT is not readily available on glibc, you need
> _XOPEN_SOURCE to be defined, which was done in
> a34e7f88f67b77066f73894dc8e42bca3c076fa6.
> 
> However, in a34e7f88f67b77066f73894dc8e42bca3c076fa6, _XOPEN_SOURCE
> was just defined, with no specific value. This caused the build to
> break again on uClibc-ng and older glibcs, because clock_gettime() and
> CLOCK_MONOTONIC were no longer defined. In both uClibc-ng and glibc,
> CLOCK_MONOTONIC is only defined if __USE_POSIX199309 is defined. It
> turns out that simply defining _XOPEN_SOURCE with no value does not
> lead to __USE_POSIX199309 being defined in uClibc-ng and old glibcs,
> while it is defined in newer glibcs.
> 
> The difference comes from the following snippet of code, which is
> present in recent enough glibc's <feature.h> but not uClibc-ng's or
> older glibc's <feature.h>:
> 
> /* If none of the ANSI/POSIX macros are defined, or if _DEFAULT_SOURCE
>     is defined, use POSIX.1-2008 (or another version depending on
>     _XOPEN_SOURCE).  */
> 
> So the fact that we are defining _DEFAULT_SOURCE makes it assume that
> we're using POSIX 2008.09, which obviously includes POSIX 1993.09.
> 
> Due to the lack of this code snippet, uClibc-ng <features.h> only
> enables:
> 
>       !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE)
> 
> but not:
> 
> So we need an _XOPEN_SOURCE level of at least 500 for POSIX 1993.09
> definitions to be available.
> 
> This is confirmed by the feature_test_macros man page, which states:
> 
>                    _XOPEN_SOURCE < 500
>                           _POSIX_C_SOURCE is defined with the value 2.
> 
>                    500 <= _XOPEN_SOURCE < 600
>                           _POSIX_C_SOURCE is defined with the value 199506L.
> 
> When this is fixed, another issue arises with older glibc toolchains
> (such as Sourcery ARM), where fd_set is no longer defined. Inded, with
> POSIX-1.2001 being enabled, we need to include <sys/select.h> to
> access the fd_set definition and friends (see man fd_set for details).
> 
> This commit was tested with two glibc toolchains (recent and old), one
> uClibc-ng toolchain and one musl toolchain.
> 
> Fixes:
> 
>    http://autobuild.buildroot.net/results/e20f9474fc0217036faa6561df33fa983466ddfe/
>    (uClibc-ng)
> 
>    http://autobuild.buildroot.net/results/b5d944389fc96ef2c5e0608fe4ac34149e5f9739/
>    (glibc)
> 
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni at bootlin.com>

Acked-by: Vincent Fazio <vfazio at gmail.com>

> ---
>   ...01-Use-LONG_BIT-to-define-RADIX_BITS.patch | 31 ++++++++++++++-----
>   1 file changed, 23 insertions(+), 8 deletions(-)
> 
> diff --git a/package/ibm-sw-tpm2/0001-Use-LONG_BIT-to-define-RADIX_BITS.patch b/package/ibm-sw-tpm2/0001-Use-LONG_BIT-to-define-RADIX_BITS.patch
> index d72239f42b..c84e359a55 100644
> --- a/package/ibm-sw-tpm2/0001-Use-LONG_BIT-to-define-RADIX_BITS.patch
> +++ b/package/ibm-sw-tpm2/0001-Use-LONG_BIT-to-define-RADIX_BITS.patch
> @@ -1,4 +1,4 @@
> -From 7c32c58f4ce802d2682038f73bb8c8f850237f89 Mon Sep 17 00:00:00 2001
> +From 5aeb25abf13de43b9e497f6509209911dd1386b8 Mon Sep 17 00:00:00 2001
>   From: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
>   Date: Sun, 26 Apr 2020 15:33:39 +0200
>   Subject: [PATCH] Use LONG_BIT to define RADIX_BITS
> @@ -6,14 +6,17 @@ Subject: [PATCH] Use LONG_BIT to define RADIX_BITS
>   This allows to avoid having to support each CPU architecture
>   individually.
>   
> -Also, add the necessary defines in the makefile to expose LONG_BIT
> +Also, add the necessary defines in the makefile to expose
> +LONG_BIT. Adding those defines end up requiring using <sys/select.h>
> +as we're now using >= POSIX.1-2001 definitions of fd_set and friends.
>   
>   Signed-off-by: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
>   Signed-off-by: Vincent Fazio <vfazio at gmail.com>
>   ---
> - src/LibSupport.h | 17 +++--------------
> - src/makefile     |  2 ++
> - 2 files changed, 5 insertions(+), 14 deletions(-)
> + src/LibSupport.h     | 17 +++--------------
> + src/TcpServerPosix.c |  1 +
> + src/makefile         |  2 ++
> + 3 files changed, 6 insertions(+), 14 deletions(-)
>   
>   diff --git a/src/LibSupport.h b/src/LibSupport.h
>   index b2e6a51..0b59d18 100644
> @@ -43,8 +46,20 @@ index b2e6a51..0b59d18 100644
>    
>    // These macros use the selected libraries to the proper include files.
>    #define LIB_QUOTE(_STRING_) #_STRING_
> +diff --git a/src/TcpServerPosix.c b/src/TcpServerPosix.c
> +index 20fcb29..bdac7aa 100644
> +--- a/src/TcpServerPosix.c
> ++++ b/src/TcpServerPosix.c
> +@@ -66,6 +66,7 @@
> +
> + #include <stdio.h>
> + /* FIXME need Posix TCP socket code */
> ++#include <sys/select.h>
> + #include <unistd.h>
> + #include <sys/types.h>
> + #include <sys/socket.h>
>   diff --git a/src/makefile b/src/makefile
> -index f124e78..9af1e51 100644
> +index f124e78..6ee128e 100644
>   --- a/src/makefile
>   +++ b/src/makefile
>   @@ -46,6 +46,8 @@ CCFLAGS = -Wall  			\
> @@ -52,10 +67,10 @@ index f124e78..9af1e51 100644
>    	-DTPM_POSIX			\
>    	-D_POSIX_			\
>   +	-D_DEFAULT_SOURCE		\
> -+	-D_XOPEN_SOURCE			\
> ++	-D_XOPEN_SOURCE=500		\
>    	-DTPM_NUVOTON
>    
>    # add this line for big endian platforms
>   --
> -2.28.0
> +2.26.2
>   
> 

-- 
Vincent Fazio
Embedded Software Engineer - Linux
Extreme Engineering Solutions, Inc
http://www.xes-inc.com



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