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

* [Buildroot] [PATCH] package/ibm-sw-tpm2: re-fix build with uClibc-ng and older glibcs
@ 2020-08-23 21:18 Thomas Petazzoni
  2020-08-24 13:28 ` Vincent Fazio
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Thomas Petazzoni @ 2020-08-23 21:18 UTC (permalink / raw)
  To: buildroot

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@bootlin.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@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@bootlin.com>
 Signed-off-by: Vincent Fazio <vfazio@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
 
-- 
2.26.2

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