Re: [PATCH] Allow [f]statfs64 to alias [f]statfs

[Steve Ellcey <sellcey@caviumnetworks.com>]

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On Mon, 2016-11-07 at 14:13 -0800, Steve Ellcey wrote:
> This is a preparatory patch for the ILP32 aarch64 patch.  On that system
> statfs and fstatfs will match statfs64 and fstatfs64.  So this patch
> follows what was already done for xstat and fxstat in making the 64
> bit entry points aliases of the regular versions.  Right now this will
> not affect any existing platform because none of them define
> STATFS_IS_STATFS64 but aarch64 will define this later.
> 
> My main question is, is this an OK use of '#ifdef' or should the
> STATFS_IS_STATFS64 be defined on all platforms (presumably in kernel_stat.h)
> so that we can check the value instead of checking to see it is defined
> or not?  I know that we want to move in that direction but I wasn't
> sure if I should include that change in this patch or not.  I also wasn't
> sure if I should try to change how XSTAT_IS_XSTAT64 or STAT_IS_KERNEL_STAT
> are used.
> 
> There are 13 kernel_stat.h files in the glibc source tree, in addition
> to a number of _HAVE_* macros, some of them define XSTAT_IS_XSTAT64
> and some define STAT_IS_KERNEL_STAT.  Those are the only defines
> in those files right now.  So the magnitude of the change isn't too large
> if we do want to define those two macros everywhere.
> 
> I tested this patch on x86 to make sure nothing broke and I tested with
> the full ILP32 aarch64 patch to make sure this part of the patch worked
> with the rest of the ILP32 changes.
> 
> Is the patch OK like this or should it be redone?
> 
> Steve Ellcey
> sellcey@caviumnetworks.com

I have modified this patch, I missed a problem in the ILP32 glibc build
and so I had to add the #define of some symbols to hide their
prototypes when aliasing them.  This in turn required me to add some
includes of kernel_stat.h.  This also matches what is being done with
xs
tat.

Steve Ellcey
sellcey@caviumnetworks.com



2016-11-09  Steve Ellcey  <sellcey@caviumnetworks.com>

	* sysdeps/unix/sysv/linux/fstatfs64.c: Hide prototypes for fstatfs
	and __fstatfs.  Make them aliases of __fstatfs64 if
	__STATFS_IS_STATFS64 is set.
	* sysdeps/unix/sysv/linux/statfs64.c: Ditto for __statfs, statfs,
	and __statfs64.
	* sysdeps/unix/sysv/linux/generic/wordsize-32/fstatfs.c: Do not
	define __fstatfs and fstatfs if __STATFS_IS_STATFS64 is set.
	* sysdeps/unix/sysv/linux/generic/wordsize-32/statfs.c: Ditto
	for __statfs and statfs.

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diff --git a/sysdeps/unix/sysv/linux/fstatfs64.c b/sysdeps/unix/sysv/linux/fstatfs64.c
index a624de6..5f56e68 100644
--- a/sysdeps/unix/sysv/linux/fstatfs64.c
+++ b/sysdeps/unix/sysv/linux/fstatfs64.c
@@ -16,9 +16,18 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
+/* Hide the prototypes for __fstatfs and fstatfs so that GCC will not
+   complain about the different function signatures if they are aliased
+   to  __fstat64.  If STATFS_IS_STATFS64 is set then the statfs and
+   statfs64 structures have an identical layout but different type names.  */
+
+#define __fstatfs __fstatfs_disable
+#define fstatfs fstatfs_disable
+
 #include <errno.h>
 #include <string.h>
 #include <sys/statfs.h>
+#include <kernel_stat.h>
 #include <stddef.h>
 #include <sysdep.h>
 #include <kernel-features.h>
@@ -70,3 +79,11 @@ __fstatfs64 (int fd, struct statfs64 *buf)
 #endif
 }
 weak_alias (__fstatfs64, fstatfs64)
+
+#undef __fstatfs
+#undef fstatfs
+
+#ifdef STATFS_IS_STATFS64
+weak_alias (__fstatfs64, __fstatfs)
+weak_alias (__fstatfs64, fstatfs)
+#endif
diff --git a/sysdeps/unix/sysv/linux/generic/wordsize-32/fstatfs.c b/sysdeps/unix/sysv/linux/generic/wordsize-32/fstatfs.c
index be9599a..3bada44 100644
--- a/sysdeps/unix/sysv/linux/generic/wordsize-32/fstatfs.c
+++ b/sysdeps/unix/sysv/linux/generic/wordsize-32/fstatfs.c
@@ -18,8 +18,10 @@
 
 #include <errno.h>
 #include <sys/statfs.h>
+#include <kernel_stat.h>
 #include <stddef.h>
 
+#ifndef STATFS_IS_STATFS64
 #include "overflow.h"
 
 /* Return information about the filesystem on which FD resides.  */
@@ -30,3 +32,4 @@ __fstatfs (int fd, struct statfs *buf)
   return rc ?: statfs_overflow (buf);
 }
 weak_alias (__fstatfs, fstatfs)
+#endif
diff --git a/sysdeps/unix/sysv/linux/generic/wordsize-32/statfs.c b/sysdeps/unix/sysv/linux/generic/wordsize-32/statfs.c
index 1937f05..aab59fd 100644
--- a/sysdeps/unix/sysv/linux/generic/wordsize-32/statfs.c
+++ b/sysdeps/unix/sysv/linux/generic/wordsize-32/statfs.c
@@ -18,8 +18,10 @@
 
 #include <errno.h>
 #include <sys/statfs.h>
+#include <kernel_stat.h>
 #include <stddef.h>
 
+#ifndef STATFS_IS_STATFS64
 #include "overflow.h"
 
 /* Return information about the filesystem on which FILE resides.  */
@@ -31,3 +33,4 @@ __statfs (const char *file, struct statfs *buf)
 }
 libc_hidden_def (__statfs)
 weak_alias (__statfs, statfs)
+#endif
diff --git a/sysdeps/unix/sysv/linux/statfs64.c b/sysdeps/unix/sysv/linux/statfs64.c
index de42261..0d881ed 100644
--- a/sysdeps/unix/sysv/linux/statfs64.c
+++ b/sysdeps/unix/sysv/linux/statfs64.c
@@ -16,9 +16,18 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
+/* Hide the prototypes for __statfs and statfs so that GCC will not
+   complain about the different function signatures if they are aliased
+   to  __stat64.  If STATFS_IS_STATFS64 is set then the statfs and
+   statfs64 structures have an identical layout but different type names.  */
+
+#define __statfs __statfs_disable
+#define statfs statfs_disable
+
 #include <errno.h>
 #include <string.h>
 #include <sys/statfs.h>
+#include <kernel_stat.h>
 #include <stddef.h>
 #include <sysdep.h>
 #include <kernel-features.h>
@@ -72,3 +81,12 @@ __statfs64 (const char *file, struct statfs64 *buf)
 #endif
 }
 weak_alias (__statfs64, statfs64)
+
+#undef __statfs
+#undef statfs
+
+#ifdef STATFS_IS_STATFS64
+weak_alias (__statfs64, __statfs)
+weak_alias (__statfs64, statfs)
+libc_hidden_ver (__statfs64, __statfs)
+#endif