diff options
Diffstat (limited to 'libc/sysdeps/linux/common/getdents.c')
| -rw-r--r-- | libc/sysdeps/linux/common/getdents.c | 119 |
1 files changed, 0 insertions, 119 deletions
diff --git a/libc/sysdeps/linux/common/getdents.c b/libc/sysdeps/linux/common/getdents.c deleted file mode 100644 index 7bb129a51..000000000 --- a/libc/sysdeps/linux/common/getdents.c +++ /dev/null @@ -1,119 +0,0 @@ -/* Copyright (C) 1993, 95, 96, 97, 98, 99 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 Library General Public License as - published by the Free Software Foundation; either version 2 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 - Library General Public License for more details. - - You should have received a copy of the GNU Library General Public - License along with the GNU C Library; see the file COPYING.LIB. If not, - write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, - Boston, MA 02111-1307, USA. */ - -#include <stdlib.h> -#include <errno.h> -#include <dirent.h> -#include <stddef.h> -#include <string.h> -#include <unistd.h> -#include <sys/param.h> -#include <sys/types.h> - -#include <sysdep.h> - -typedef long __kernel_off_t; - -#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER) - - -extern int _getdents __P ((int fd, char *buf, size_t nbytes)); - -/* For Linux we need a special version of this file since the - definition of `struct dirent' is not the same for the kernel and - the libc. There is one additional field which might be introduced - in the kernel structure in the future. Here is a copy of the kernel - struct dirent... - */ -struct kernel_dirent { - long d_ino; - __kernel_off_t d_off; - unsigned short d_reclen; - char d_name[256]; /* We must not include limits.h! */ -}; - - - -#ifdef GETDENTS64 -# define __getdents __getdents64 -# define dirent dirent64 -#endif - -/* The problem here is that we cannot simply read the next NBYTES - bytes. We need to take the additional field into account. We use - some heuristic. Assuming the directory contains names with 14 - characters on average we can compute an estimated number of entries - which fit in the buffer. Taking this number allows us to specify a - reasonable number of bytes to read. If we should be wrong, we can - reset the file descriptor. In practice the kernel is limiting the - amount of data returned much more then the reduced buffer size. */ -ssize_t getdents (int fd, char *buf, size_t nbytes) -{ - off_t last_offset = 0; - size_t red_nbytes; - struct kernel_dirent *skdp, *kdp; - struct dirent *dp; - int retval; - const size_t size_diff = (offsetof (struct dirent, d_name) - - offsetof (struct kernel_dirent, d_name)); - - red_nbytes = nbytes - ((nbytes / (offsetof (struct dirent, d_name) + 14)) - * size_diff); - - dp = (struct dirent *) buf; - skdp = kdp = malloc (red_nbytes); - - retval = _getdents(fd, (char *) kdp, red_nbytes); - - if (retval == -1) - return -1; - - while ((char *) kdp < (char *) skdp + retval) - { - const size_t alignment = __alignof__ (struct dirent); - /* 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. `last_offset' contains the last known - position. If it is zero this is the first record we are - reading. In this case do a relative search. */ - if (last_offset == 0) - lseek (fd, -retval, SEEK_CUR); - else - lseek (fd, last_offset, SEEK_SET); - 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_dirent, d_name)); - - dp = (struct dirent *) ((char *) dp + new_reclen); - kdp = (struct kernel_dirent *) (((char *) kdp) + kdp->d_reclen); - } - - return (char *) dp - buf; -} |