On Linux, afs/param.h determines whether to use the ucontext()
function based on the glibc version. However, the glibc version
macros aren't available until a C library header has been included.
There have been a couple of attempts to fix this. The first included
afs_sysnames.h before the C library check, but this wasn't sufficient
to pull in a header for all builds. The second included stdio.h before
including afs/param.h in process.c.
Whilst the second approach works, it has the drawback that it breaks
our convention that afsconfig.h and afs/param.h must always be the first
includes in a file. More seriously, it means that the behaviour of
afs/param.h is different depending on where it appears in the include
order - which is especially dangerous for 3rd party user.
So, this patch tries to resolve all of this by explicitly including
features.h before doing the glibc version checks. The only danger I
can see here is that Linux platforms without glibc may lack a
features.h, but I suspect we have trouble building on such platforms
in any case.
Change-Id: Ief96d32b10372225335e2d2fbb7205da4bf5fc0a
Reviewed-on: http://gerrit.openafs.org/4389
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
#endif /* !defined(UKERNEL) */
-/* needed so glibc version will be defined */
-#include <afs/afs_sysnames.h>
+#if defined(UKERNEL) || !defined(KERNEL)
+#include <features.h>
+#endif
#ifdef __GLIBC__
#if (__GLIBC__ > 2) || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 3)
#endif
#endif
+#include <afs/afs_sysnames.h>
+
#endif /* AFS_PARAM_COMMON_H */
#endif /* !defined(UKERNEL) */
-/* needed so glibc version will be defined */
-#include <afs/afs_sysnames.h>
+#if defined(UKERNEL) || !defined(KERNEL)
+#include <features.h>
+#endif
#ifdef __GLIBC__
#if (__GLIBC__ > 2) || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 3)
#endif
#endif
+#include <afs/afs_sysnames.h>
+
#endif /* AFS_PARAM_COMMON_H */
/* process.c - manage lwp context switches be means of setjmp/longjmp. */
#include <afsconfig.h>
+#include <afs/param.h>
-/*
- * We must include at least one system header on Linux prior to including
- * afs/param.h, or the __GLIBC__ and __GLIBC_MINOR__ macros will not yet be
- * defined and we won't know whether we're using ucontext.
- */
#include <stdio.h>
#include <assert.h>
#ifdef HAVE_STDLIB_H
# include <stdlib.h>
#endif
-#include <afs/param.h>
#include "lwp.h"