linux: Consolidate fxstatat{64}

The LFS support is implemented on fxstat64.c, instead of fxstat.c for
64-bit architectures.  The fxstatat.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 issues __NR_fstatat64 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, mips32,
     microblaze, s390, sh, powerpc, and sparc32).  it issues
     __NR_fstatat64 and convert to non-LFS stat struct based on the
     version.

Also non-LFS mips64 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 issues __NR_newfstatat for _STAT_VER_KERNEL or
         _STAT_VER_LINUX.

    1.2. 64-bit kABI outlier (sparc64): it issuess fstatat64 with a
         temporary stat64 and convert to output stat64 based on the
         input version (and using a sparc64 specific __xstat32_conv).

    1.3. New 32-bit kABIs with only 64-bit time_t support (arc and
	 riscv32): it issues __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 uses the __NR_fstatat64 syscall instead.

  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>

3 files changed, 38 insertions, 24 deletions

diff --git a/sysdeps/unix/sysv/linux/mips/mips32/fxstatat.c b/sysdeps/unix/sysv/linux/mips/mips32/fxstatat.c
deleted file mode 100644
index 0f8b3135d8..0000000000
--- a/sysdeps/unix/sysv/linux/mips/mips32/fxstatat.c
+++ /dev/null
@@ -1 +0,0 @@
-#include <sysdeps/unix/sysv/linux/i386/fxstatat.c>
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/fxstatat.c b/sysdeps/unix/sysv/linux/mips/mips64/fxstatat.c
new file mode 100644
index 0000000000..58410a1441
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/mips/mips64/fxstatat.c
@@ -0,0 +1,33 @@
+/* fxstat using old-style Unix fstat system call.
+   Copyright (C) 1991-2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <kernel_stat.h>
+#include <sysdep.h>
+#include <xstatconv.h>
+
+/* Get information about the file FD in BUF.  */
+int
+__fxstatat (int vers, int fd, const char *file, struct stat *st, int flag)
+{
+  struct kernel_stat kst;
+  int r = INLINE_SYSCALL_CALL (newfstatat, fd, file, &kst, flag);
+  return r ?: __xstat_conv (vers, &kst, st);
+}
+libc_hidden_def (__fxstatat)
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/fxstatat64.c b/sysdeps/unix/sysv/linux/mips/mips64/fxstatat64.c
index 62df5fb26c..e5416d8971 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/fxstatat64.c
+++ b/sysdeps/unix/sysv/linux/mips/mips64/fxstatat64.c
@@ -15,17 +15,9 @@
    License along with the GNU C Library.  If not, see
    <https://www.gnu.org/licenses/>.  */
 
-#include <errno.h>
-#include <fcntl.h>
-#include <stddef.h>
-#include <stdio.h>
-#include <string.h>
 #include <sys/stat.h>
 #include <kernel_stat.h>
-
 #include <sysdep.h>
-#include <sys/syscall.h>
-
 #include <xstatconv.h>
 
 /* Get information about the file NAME in BUF.  */
@@ -33,22 +25,12 @@
 int
 __fxstatat64 (int vers, int fd, const char *file, struct stat64 *st, int flag)
 {
-  if (__builtin_expect (vers != _STAT_VER_LINUX, 0))
-    {
-      __set_errno (EINVAL);
-      return -1;
-    }
-
-  int result;
-  struct kernel_stat kst;
-
-  result = INTERNAL_SYSCALL_CALL (newfstatat, fd, file, &kst, flag);
-  if (!__glibc_likely (INTERNAL_SYSCALL_ERROR_P (result)))
-    return __xstat64_conv (vers, &kst, st);
-  else
+  if (vers == _STAT_VER_LINUX)
     {
-      __set_errno (INTERNAL_SYSCALL_ERRNO (result));
-      return -1;
+      struct kernel_stat kst;
+      int r = INLINE_SYSCALL_CALL (newfstatat, fd, file, &kst, flag);;
+      return r ?: __xstat64_conv (vers, &kst, st);
     }
+  return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
 }
 libc_hidden_def (__fxstatat64)