Consolidate Linux getdents{64} implementation

This patch consolidates Linux getdents{64} implementation on just
the default sysdeps/unix/sysv/linux/getdents{64}{_r}.c ones.

Although this symbol is used only internally, the non-LFS version
still need to be build due the non-LFS getdirentries which requires
its semantic.

The non-LFS default implementation now uses the wordsize-32 as base
which uses getdents64 syscall plus adjustment for overflow (it allows
to use the same code for architectures that does not support non-LFS
getdents syscall).  It has two main differences to wordsize-32 one:

  - DIRENT_SET_DP_INO is added to handle alpha requirement to zero
    the padding.

  - alloca is removed by allocating a bounded temporary buffer (it
    increases stack usage by roughly 276 bytes).

The default implementation handle the Linux requirements:

  * getdents is only built for _DIRENT_MATCHES_DIRENT64 being 0.

  * getdents64 is always built and aliased to getdents for ABIs
    that define _DIRENT_MATCHES_DIRENT64 to 1.

  * A compat symbol is added for getdents64 for ABI that used to
    export the old non-LFS version.

Checked on aarch64-linux-gnu, x86_64-linux-gnu, i686-linux-gnu,
sparcv9-linux-gnu, sparc64-linux-gnu, powerpc-linux-gnu, and
powerpc64le-linux-gnu.

	* sysdeps/unix/sysv/linux/alpha/getdents.c: Add comments with alpha
	requirements.
	 (_DIRENT_MATCHES_DIRENT64): Undef
	* sysdeps/unix/sysv/linux/alpha/getdents64.c: Likewise.
	* sysdeps/unix/sysv/linux/arm/getdents64.c: Remove file.
	* sysdeps/unix/sysv/linux/generic/getdents.c: Likewise.
	* sysdeps/unix/sysv/linux/generic/getdents64.c: Likewise.
	* sysdeps/unix/sysv/linux/generic/wordsize-32/getdents.c: Likewise.
	* sysdeps/unix/sysv/linux/getdents.c: Simplify implementation by
	use getdents64 syscalls as base.
	* sysdeps/unix/sysv/linux/getdents64.c: Likewise and add compatibility
	symbol if required.
	* sysdeps/unix/sysv/linux/hppa/getdents64.c: Likewise.
	* sysdeps/unix/sysv/linux/i386/getdents64.c: Likewise.
	* sysdeps/unix/sysv/linux/m68k/getdents64.c: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/getdents64.c: Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-32/getdents64.c: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc32/getdents64.c: Likewise.
	* sysdeps/unix/sysv/linux/wordsize-64/getdents.c: Likewise.
	* sysdeps/unix/sysv/linux/wordsize-64/getdents64.c: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc64/get_clockfreq.c
	(__get_clockfreq_via_proc_openprom): Use __getdents64.
	* sysdeps/unix/sysv/linux/mips/mips64/getdents64.c: New file.

3 files changed, 0 insertions, 153 deletions

diff --git a/sysdeps/unix/sysv/linux/generic/getdents.c b/sysdeps/unix/sysv/linux/generic/getdents.c
deleted file mode 100644
index 14dbbc71a0..0000000000
--- a/sysdeps/unix/sysv/linux/generic/getdents.c
+++ /dev/null
@@ -1 +0,0 @@
-/* Defined in getdents64.c */
diff --git a/sysdeps/unix/sysv/linux/generic/getdents64.c b/sysdeps/unix/sysv/linux/generic/getdents64.c
deleted file mode 100644
index 0f876b8172..0000000000
--- a/sysdeps/unix/sysv/linux/generic/getdents64.c
+++ /dev/null
@@ -1,37 +0,0 @@
-/* Copyright (C) 2011-2018 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011.
-
-   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
-   <http://www.gnu.org/licenses/>.  */
-
-#include <stddef.h>
-#include <stdint.h>
-#include <unistd.h>
-#include <sys/types.h>
-#include <bits/wordsize.h>
-
-#include <sysdep.h>
-#include <sys/syscall.h>
-
-/* The kernel struct linux_dirent64 matches the 'struct getdents64' type.  */
-ssize_t
-__getdents64 (int fd, char *buf, size_t nbytes)
-{
-  return INLINE_SYSCALL (getdents64, 3, fd, buf, nbytes);
-}
-
-#if __WORDSIZE == 64
-strong_alias (__getdents64, __getdents)
-#endif
diff --git a/sysdeps/unix/sysv/linux/generic/wordsize-32/getdents.c b/sysdeps/unix/sysv/linux/generic/wordsize-32/getdents.c
deleted file mode 100644
index 7158fd1752..0000000000
--- a/sysdeps/unix/sysv/linux/generic/wordsize-32/getdents.c
+++ /dev/null
@@ -1,115 +0,0 @@
-/* Copyright (C) 1993-2018 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Simplified from sysdeps/unix/sysv/linux/getdents.c.
-
-   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
-   <http://www.gnu.org/licenses/>.  */
-
-#include <alloca.h>
-#include <assert.h>
-#include <errno.h>
-#include <dirent.h>
-#include <stddef.h>
-#include <stdint.h>
-#include <string.h>
-#include <unistd.h>
-#include <sys/param.h>
-#include <sys/types.h>
-
-#include <sysdep.h>
-#include <sys/syscall.h>
-
-/* Pack the dirent64 struct down into 32-bit offset/inode fields, and
-   ensure that no overflow occurs.  */
-ssize_t
-__getdents (int fd, char *buf, size_t nbytes)
-{
-  union
-  {
-    struct dirent64 k;  /* Kernel structure.  */
-    struct dirent u;
-    char b[1];
-  } *kbuf = (void *) buf, *outp, *inp;
-  size_t kbytes = nbytes;
-  off64_t last_offset = -1;
-  ssize_t retval;
-
-  const size_t size_diff = (offsetof (struct dirent64, d_name)
-                            - offsetof (struct dirent, d_name));
-  if (nbytes <= sizeof (struct dirent))
-    {
-      kbytes = nbytes + offsetof (struct dirent64, d_name)
-        - offsetof (struct dirent, d_name);
-      kbuf = __alloca(kbytes);
-    }
-
-  retval = INLINE_SYSCALL (getdents64, 3, fd, kbuf, kbytes);
-  if (retval == -1)
-    return -1;
-
-  /* These two pointers might alias the same memory buffer.
-     Standard C requires that we always use the same type for them,
-     so we must use the union type.  */
-  inp = kbuf;
-  outp = (void *) buf;
-
-  while (&inp->b < &kbuf->b + retval)
-    {
-      const size_t alignment = __alignof__ (struct dirent);
-      /* Since inp->k.d_reclen is already aligned for the kernel
-         structure this may compute a value that is bigger
-         than necessary.  */
-      size_t old_reclen = inp->k.d_reclen;
-      size_t new_reclen = ((old_reclen - size_diff + alignment - 1)
-                           & ~(alignment - 1));
-
-      /* Copy the data out of the old structure into temporary space.
-         Then copy the name, which may overlap if BUF == KBUF.  */
-      const uint64_t d_ino = inp->k.d_ino;
-      const int64_t d_off = inp->k.d_off;
-      const uint8_t d_type = inp->k.d_type;
-
-      memmove (outp->u.d_name, inp->k.d_name,
-               old_reclen - offsetof (struct dirent64, d_name));
-
-      /* Now we have copied the data from INP and access only OUTP.  */
-
-      outp->u.d_ino = d_ino;
-      outp->u.d_off = d_off;
-      if ((sizeof (outp->u.d_ino) != sizeof (inp->k.d_ino)
-           && outp->u.d_ino != d_ino)
-          || (sizeof (outp->u.d_off) != sizeof (inp->k.d_off)
-              && outp->u.d_off != d_off))
-        {
-          /* Overflow.  If there was at least one entry before this one,
-             return them without error, otherwise signal overflow.  */
-          if (last_offset != -1)
-            {
-              __lseek64 (fd, last_offset, SEEK_SET);
-              return outp->b - buf;
-            }
-          __set_errno (EOVERFLOW);
-          return -1;
-        }
-
-      last_offset = d_off;
-      outp->u.d_reclen = new_reclen;
-      outp->u.d_type = d_type;
-
-      inp = (void *) inp + old_reclen;
-      outp = (void *) outp + new_reclen;
-    }
-
-  return outp->b - buf;
-}