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/* Copyright (C) 1993, 1995-2002 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, write to the Free

   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA

   02111-1307 USA.  */

#include <features.h>

#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 <sysdep.h>

#include <sys/param.h>

#include <sys/types.h>

#include <sys/syscall.h>

#if defined __UCLIBC_HAS_LFS__ && defined __NR_getdents64 

#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)

struct kernel_dirent64

{

    uint64_t            d_ino;

    int64_t             d_off;

    unsigned short      d_reclen;

    unsigned char       d_type;

    char                d_name[256];

};

#define __NR___syscall_getdents64 __NR_getdents64

static inline _syscall3(int, __syscall_getdents64, int, fd, unsigned char *, dirp, size_t, count);

ssize_t __getdents64 (int fd, char *buf, size_t nbytes)

{

    struct dirent64 *dp;

    off64_t last_offset = -1;

    ssize_t retval;

    size_t red_nbytes;

    struct kernel_dirent64 *skdp, *kdp;

    const size_t size_diff = (offsetof (struct dirent64, d_name)

            - offsetof (struct kernel_dirent64, d_name));

    red_nbytes = MIN (nbytes - ((nbytes /

                    (offsetof (struct dirent64, d_name) + 14)) * size_diff),

            nbytes - size_diff);

    dp = (struct dirent64 *) buf;

    skdp = kdp = alloca (red_nbytes);

    retval = __syscall_getdents64(fd, (char *)kdp, red_nbytes);

    if (retval == -1)

        return -1;

    while ((char *) kdp < (char *) skdp + retval) {

        const size_t alignment = __alignof__ (struct dirent64);

        /* Since kdp->d_reclen is already aligned for the kernel structure

           this may compute a value that is bigger than necessary.  */

        size_t new_reclen = ((kdp->d_reclen + size_diff + alignment - 1)

                & ~(alignment - 1));

        if ((char *) dp + new_reclen > buf + nbytes) {

            /* Our heuristic failed.  We read too many entries.  Reset

               the stream.  */

            assert (last_offset != -1);

            lseek64(fd, last_offset, SEEK_SET);

            if ((char *) dp == buf) {

                /* The buffer the user passed in is too small to hold even

                   one entry.  */

                __set_errno (EINVAL);

                return -1;

            }

            break;

        }

        last_offset = kdp->d_off;

        dp->d_ino = kdp->d_ino;

        dp->d_off = kdp->d_off;

        dp->d_reclen = new_reclen;

        dp->d_type = DT_UNKNOWN;

        memcpy (dp->d_name, kdp->d_name,

                kdp->d_reclen - offsetof (struct kernel_dirent64, d_name));

        dp = (struct dirent64 *) ((char *) dp + new_reclen);

        kdp = (struct kernel_dirent64 *) (((char *) kdp) + kdp->d_reclen);

    }

    return (char *) dp - buf;

}

#else

ssize_t __getdents (int fd, char *buf, size_t nbytes);

ssize_t __getdents64 (int fd, char *buf, size_t nbytes)

{

    return(__getdents(fd, buf, nbytes));

}

#endif /* __UCLIBC_HAS_LFS__ */