readdir64.c

Newlib 嵌入式 C库 标准实现代码

/*
 * Copyright (c) 1983 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/* Modified from newlib/libc/posix/readdir.c */

#include <dirent.h>
#include <machine/syscall.h>

#define __NR___getdents64 __NR_getdents64

static _syscall3(int,__getdents64,int,fd,struct dirent64 *,dirp,unsigned int,count)

/*
 * get next entry in a directory.
 */
struct dirent64 *
__readdir64 (dirp)
register DIR *dirp; {
  register struct dirent64 *dp;
 
#ifdef HAVE_DD_LOCK
  __lock_acquire_recursive(dirp->dd_lock);
#endif

  if (dirp->dd_fd == -1)
    return NULL;
 
  for (;;) {
    if (dirp->dd_loc == 0) {
      dirp->dd_size = __getdents64 (dirp->dd_fd,
				    (void *)dirp->dd_buf,
				    dirp->dd_len);
      
      if (dirp->dd_size <= 0) {
#ifdef HAVE_DD_LOCK
        __lock_release_recursive(dirp->dd_lock);
#endif
	return NULL;
      }
    }
    if (dirp->dd_loc >= dirp->dd_size) {
      dirp->dd_loc = 0;
      continue;
    }
    dp = (struct dirent64 *)(dirp->dd_buf + dirp->dd_loc);
    if ((int)dp & 03) {	/* bogus pointer check */
#ifdef HAVE_DD_LOCK
      __lock_release_recursive(dirp->dd_lock);
#endif
      return NULL;
    }
    if (dp->d_reclen <= 0 ||
	dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc) {
#ifdef HAVE_DD_LOCK
      __lock_release_recursive(dirp->dd_lock);
#endif
      return NULL;
    }
    dirp->dd_loc += dp->d_reclen;
    if (dp->d_ino == 0)
      continue;
#ifdef HAVE_DD_LOCK
    __lock_release_recursive(dirp->dd_lock);
#endif
    return (dp);
  }
}