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>

1 files changed, 60 insertions, 8 deletions

diff --git a/sysdeps/unix/sysv/linux/lxstat64.c b/sysdeps/unix/sysv/linux/lxstat64.c
index 0ea8399..d0d8b5f 100644
--- a/sysdeps/unix/sysv/linux/lxstat64.c
+++ b/sysdeps/unix/sysv/linux/lxstat64.c
@@ -1,5 +1,5 @@
 /* lxstat64 using Linux lstat64 system call.
-   Copyright (C) 1997-2020 Free Software Foundation, Inc.
+   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
@@ -16,23 +16,75 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#include <errno.h>
-#include <stddef.h>
+#define __lxstat __redirect___lxstat
 #include <sys/stat.h>
+#undef __lxstat
+#include <fcntl.h>
 #include <kernel_stat.h>
-
 #include <sysdep.h>
-#include <sys/syscall.h>
+#include <xstatconv.h>
+#include <statx_cp.h>
 
 /* Get information about the file NAME in BUF.  */
+
 int
 ___lxstat64 (int vers, const char *name, struct stat64 *buf)
 {
-  int result;
-  result = INLINE_SYSCALL (lstat64, 2, name, buf);
-  return result;
+#if XSTAT_IS_XSTAT64
+# ifdef __NR_lstat64
+  /* 64-bit kABI outlier, e.g. sparc64.  */
+  if (vers == _STAT_VER_KERNEL)
+    return INLINE_SYSCALL_CALL (lstat, name, buf);
+  else
+    {
+      struct stat64 st64;
+      int r = INLINE_SYSCALL_CALL (lstat64, name, &st64);
+      return r ?: __xstat32_conv (vers, &st64, (struct stat *) buf);
+    }
+# elif defined __NR_lstat
+  /* Old 64-bit kABI, e.g. ia64, powerpc64*, s390x, and x86_64.  */
+  if (vers == _STAT_VER_KERNEL || vers == _STAT_VER_LINUX)
+    return INLINE_SYSCALL_CALL (lstat, name, buf);
+# elif defined __NR_newfstatat
+  /* New kABIs which uses generic 64-bit Linux ABI, e.g. aarch64, riscv64.  */
+  if (vers == _STAT_VER_KERNEL)
+    return INLINE_SYSCALL_CALL (newfstatat, AT_FDCWD, name, buf,
+				AT_SYMLINK_NOFOLLOW);
+# else
+  /* New 32-bit kABIs with only 64-bit time_t support, e.g. arc, riscv32.  */
+  if (vers == _STAT_VER_KERNEL)
+    {
+      struct statx tmp;
+      int r = INLINE_SYSCALL_CALL (statx, AT_FDCWD, name,
+				   AT_NO_AUTOMOUNT | AT_SYMLINK_NOFOLLOW,
+				   STATX_BASIC_STATS, &tmp);
+      if (r == 0)
+	__cp_stat64_statx (buf, &tmp);
+      return r;
+     }
+# endif
+#else
+# if STAT_IS_KERNEL_STAT
+  /* New kABIs which uses generic pre 64-bit time Linux ABI,
+     e.g. csky, nios2  */
+  if (vers == _STAT_VER_KERNEL)
+    return INLINE_SYSCALL_CALL (fstatat64, AT_FDCWD, name, buf,
+				AT_SYMLINK_NOFOLLOW);
+# else
+  /* Old kABIs with old non-LFS support, e.g. arm, i386, hppa, m68k,
+     microblaze, s390, sh, mips32, powerpc32, and sparc32.  */
+  return INLINE_SYSCALL_CALL (lstat64, name, buf);
+# endif /* STAT_IS_KERNEL_STAT  */
+#endif /* XSTAT_IS_XSTAT64  */
+
+  return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
 }
 
+#if XSTAT_IS_XSTAT64
+weak_alias (___lxstat64, __lxstat);
+weak_alias (___lxstat64, __GI___lxstat);
+#endif
+
 #include <shlib-compat.h>
 
 #if SHLIB_COMPAT(libc, GLIBC_2_1, GLIBC_2_2)