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Consolidate Linux getdents{64} implementation

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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.
This commit is contained in:
Adhemerval Zanella
2018-02-28 15:37:17 -03:00
parent 0085be1415
commit 298d0e3129
19 changed files with 316 additions and 449 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
sysdeps/unix/sysv/linux/generic/getdents.c
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@ -1 +0,0 @@
/* Defined in getdents64.c */

37
sysdeps/unix/sysv/linux/generic/getdents64.c
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@ -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

115
sysdeps/unix/sysv/linux/generic/wordsize-32/getdents.c
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@ -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;
}