linux: Consolidate fxstat{64}

The LFS support is implemented on fxstat64.c, instead of fxstat.c for
64-bit architectures.  The fxstat.c implements the non-LFS and it is
a no-op for !XSTAT_IS_XSTAT64.

The generic non-LFS implementation handles two cases:

  1. New kABIs which uses generic pre 64-bit time Linux ABI (csky and
     nios): it issuess __NR_fstat64 plus handle the overflow on st_ino,
     st_size, or st_blocks.  It only handles _STAT_VER_KERNEL.

  2. Old KABIs with old non-LFS support (arm, i386, hppa, m68k,
     microblaze, s390, sh, powerpc, and sparc32).  For _STAT_VER_KERNEL
     it issues __NR_fstat, otherwise it calls __NR_fstat64 and convert
     to non-LFS stat struct and handle possible overflows on st_ino,
     st_size, or st_blocks.

Also non-LFS mips is an outlier and it has its own implementation since
_STAT_VER_LINUX requires a different conversion function (it uses the
kernel_stat as the sysissues argument since its exported ABI is
different than the kernel one for both non-LFS and LFS implementation).

The generic LFS implementation handles multiple cases:

  1. XSTAT_IS_XSTAT64 being 1:

    1.1. 64-bit kABI (aarch64, ia64, powerpc64*, s390x, riscv64, and
	 x86_64): it issuess __NR_fstat for _STAT_VER_KERNEL or
	 _STAT_VER_LINUX.

    1.2. Old 64-bit kABI with defines __NR_fstat64 instead of __NR_fstat
         (sparc64): it issues __NR_fstat for _STAT_VER_KERNEL or
         __NR_fstat64 and convert to struct stat64.

    1.3. New 32-bit kABIs with only 64-bit time_t support (arc and
	 riscv32): it issuess __NR_statx and covert to struct stat64.

  2. Old ABIs with XSTAT_IS_XSTAT64 being 0 (arm, csky, i386, hppa,
     m68k, microblaze, mips32, nios2, sh, powerpc32, and sparc32): it
     issues __NR_fstat64.

Also, two special cases requires specific implementations:

  1. alpha: it requires to handle _STAT_VER_KERNEL64 to issues
     __NR_fstat64 and use the kernel_stat with __NR_fstat otherwise.

  2. mips64: as for non-LFS implementation its ABIs differ from
     glibc exported one, which requires an specific conversion
     function to handle the kernel_stat.

Checked with a build for all affected ABIs. I also checked on x86_64,
i686, powerpc, powerpc64le, sparcv9, sparc64, s390, and s390x.

Reviewed-by: Lukasz Majewski <lukma@denx.de>

1 files changed, 19 insertions, 29 deletions

diff --git a/sysdeps/unix/sysv/linux/alpha/fxstat.c b/sysdeps/unix/sysv/linux/alpha/fxstat64.c
index 0978610bf0..286a2f0a6c 100644
--- a/sysdeps/unix/sysv/linux/alpha/fxstat.c
+++ b/sysdeps/unix/sysv/linux/alpha/fxstat64.c
@@ -1,4 +1,4 @@
-/* fxstat using old-style Unix stat system call.
+/* fxstat64 using old-style Unix stat system call.
    Copyright (C) 2004-2020 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
@@ -16,42 +16,32 @@
    License along with the GNU C Library.  If not, see
    <https://www.gnu.org/licenses/>.  */
 
-#define __fxstat64 __fxstat64_disable
-
-#include <errno.h>
-#include <stddef.h>
+#define __fxstat __redirect___fxstat64
 #include <sys/stat.h>
+#undef __fxstat
 #include <kernel_stat.h>
 #include <sysdep.h>
-#include <sys/syscall.h>
 #include <xstatconv.h>
 
-#undef __fxstat64
-
-
 /* Get information about the file NAME in BUF.  */
 int
-__fxstat (int vers, int fd, struct stat *buf)
+__fxstat64 (int vers, int fd, struct stat64 *buf)
 {
-  int result;
-  struct kernel_stat kbuf;
-
-  if (vers == _STAT_VER_KERNEL64)
+  switch (vers)
     {
-      result = INTERNAL_SYSCALL_CALL (fstat64, fd, buf);
-      if (__glibc_likely (!INTERNAL_SYSCALL_ERROR_P (result)))
-	return result;
-      __set_errno (INTERNAL_SYSCALL_ERRNO (result));
-      return -1;
+    case _STAT_VER_KERNEL64:
+      return INLINE_SYSCALL_CALL (fstat64, fd, buf);
+
+    default:
+      {
+        struct kernel_stat kbuf;
+	int r = INTERNAL_SYSCALL_CALL (fstat, fd, &kbuf);
+	if (r == 0)
+	  return __xstat_conv (vers, &kbuf, buf);
+	return INLINE_SYSCALL_ERROR_RETURN_VALUE (-r);
+      }
     }
-
-  result = INTERNAL_SYSCALL_CALL (fstat, fd, &kbuf);
-  if (__glibc_likely (!INTERNAL_SYSCALL_ERROR_P (result)))
-    return __xstat_conv (vers, &kbuf, buf);
-  __set_errno (INTERNAL_SYSCALL_ERRNO (result));
-  return -1;
 }
-hidden_def (__fxstat)
-weak_alias (__fxstat, _fxstat);
-strong_alias (__fxstat, __fxstat64);
-hidden_ver (__fxstat, __fxstat64)
+hidden_def (__fxstat64)
+strong_alias (__fxstat64, __fxstat);
+hidden_ver (__fxstat64, __fxstat)