linux: Consolidate lxstat{64}

The LFS support is implemented on lxstat64.c, instead of lxstat.c for
64-bit architectures.  The xstat.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_fstat64 with AT_SYMLINK_NOFOLLOW plus handles
     the possible overflow off 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_lstat, otherwise it isseus __NR_lstat64 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 syscall 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. Old 64-bit kABI (ia64, powerpc64*, s390x, sparc64, x86_64): it
         issues __NR_lstat for _STAT_VER_KERNEL or _STAT_VER_LINUX.

    1.2. Old 64-bit kABI with defines __NR_lstat64 instead of __NR_lstat
         (sparc64): it issues __NR_lstat for _STAT_VER_KERNEL or
         __NR_lstat64 and convert to struct stat64.

    1.3. New kABIs which uses generic 64-bit Linux ABI (aarch64 and
         riscv64): it issues __NR_newfstatat with AT_SYMLINK_NOFOLLOW
	 and only for _STAT_VER_KERNEL.

    1.4. 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:

    2.1. New kABIs which uses generic pre 64-bit time Linux ABI (csky
	 and nios2): it issues __NR_fstatat64 for _STAT_VER_KERNEL.

    2.2. Old kABIs with old non-LFS support (arm, i386, hppa, m68k,
	 microblaze, s390, sh, mips32, powerpc32, and sparc32): it
	 issues __NR_lstat64.

Also, two special cases requires specific LFS implementations:

  1. alpha: it requires to handle _STAT_VER_KERNEL64 to issue
     __NR_lstat64 and use the kernel_stat with __NR_lstat otherwise.

  2. mips64: as for non-LFS implementation its ABIs differ from
     glibc exported one, which requires a 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>

2 files changed, 44 insertions, 12 deletions

diff --git a/sysdeps/unix/sysv/linux/mips/lxstat.c b/sysdeps/unix/sysv/linux/mips/lxstat.c
new file mode 100644
index 0000000000..eb07549adf
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/mips/lxstat.c
@@ -0,0 +1,42 @@
+/* lxstat using old-style Unix stat 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 NAME in BUF.  */
+int
+__lxstat (int vers, const char *name, struct stat *buf)
+{
+  switch (vers)
+    {
+    case _STAT_VER_KERNEL:
+      return INLINE_SYSCALL_CALL (lstat, name, buf);
+
+    default:
+      {
+	struct kernel_stat kbuf;
+	int r = INTERNAL_SYSCALL_CALL (lstat, name, &kbuf);
+	return r ?: __xstat_conv (vers, &kbuf, buf);
+      }
+    }
+}
+hidden_def (__lxstat)
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/lxstat64.c b/sysdeps/unix/sysv/linux/mips/mips64/lxstat64.c
index 62d4fe70eb..28bac57e58 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/lxstat64.c
+++ b/sysdeps/unix/sysv/linux/mips/mips64/lxstat64.c
@@ -16,28 +16,18 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#include <errno.h>
-#include <stddef.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.  */
 int
 __lxstat64 (int vers, const char *name, struct stat64 *buf)
 {
-  int result;
   struct kernel_stat kbuf;
-
-  result = INLINE_SYSCALL (lstat, 2, name, &kbuf);
-  if (result == 0)
-    result = __xstat64_conv (vers, &kbuf, buf);
-
-  return result;
+  int r = INLINE_SYSCALL_CALL (lstat, name, &kbuf);
+  return r ?: __xstat64_conv (vers, &kbuf, buf);
 }
 
 hidden_def (__lxstat64)