linux: Consolidate fstatfs implementations

The __NR_fstatfs64 syscall is supported on all architectures but
aarch64, mips64, riscv64, and x86_64.  And newer ABIs also uses
the new fstatfs64 interface (where the struct size is used as
first argument).

So the default implementation now uses:

  1. __NR_fstatfs64 for non-LFS call and handle overflow directly
     There is no need to handle __NR_fstatfs since all architectures
     that only support are LFS only.

  2. __NR_fstatfs if defined or __NR_fstatfs64 otherwise for LFS
     call.

Alpha is the only outlier, it is a 64-bit architecture which
provides non-LFS interface and only provides __NR_fstatfs64 on
newer kernels (5.1+).

Checked on x86_64-linux-gnu.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

1 files changed, 62 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/fstatfs.c b/sysdeps/unix/sysv/linux/fstatfs.c
new file mode 100644
index 0000000000..38d621967e
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/fstatfs.c
@@ -0,0 +1,62 @@
+/* Get filesystem statistics.  Linux version.
+   Copyright (C) 2021 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/statfs.h>
+#include <time.h>
+#include <sysdep.h>
+#include <kernel_stat.h>
+
+#if !STATFS_IS_STATFS64
+
+/* Return information about the filesystem on which FILE resides.  */
+int
+__fstatfs (int fd, struct statfs *buf)
+{
+  struct statfs64 buf64;
+  int rc = INLINE_SYSCALL_CALL (fstatfs64, fd, sizeof (buf64), &buf64);
+  if (rc != 0)
+    return rc;
+
+  buf->f_type = buf64.f_type;
+  buf->f_bsize = buf64.f_bsize;
+  buf->f_blocks = buf64.f_blocks;
+  buf->f_bfree = buf64.f_bfree;
+  buf->f_bavail = buf64.f_bavail;
+  buf->f_files = buf64.f_files;
+  buf->f_ffree = buf64.f_ffree;
+  buf->f_fsid = buf64.f_fsid;
+  buf->f_namelen = buf64.f_namelen;
+  buf->f_frsize = buf64.f_frsize;
+  buf->f_flags = buf64.f_flags;
+  memcpy (buf->f_spare, buf64.f_spare, sizeof (buf64.f_spare));
+
+  if ((fsblkcnt_t) buf64.f_blocks != buf64.f_blocks
+      || (fsblkcnt_t) buf64.f_bfree != buf64.f_bfree
+      || (fsblkcnt_t) buf64.f_bavail != buf64.f_bavail
+      || (fsblkcnt_t) buf64.f_files != buf64.f_files
+      || (fsblkcnt_t) buf64.f_ffree != buf64.f_ffree)
+   {
+     __set_errno (EOVERFLOW);
+     return -1;
+   }
+
+  return 0;
+}
+libc_hidden_def (__fstatfs)
+weak_alias (__fstatfs, fstatfs)
+#endif