143 строки
3.6 KiB
C
143 строки
3.6 KiB
C
/*
|
|
* dir.c
|
|
*
|
|
* PURPOSE
|
|
* Directory handling routines for the OSTA-UDF(tm) filesystem.
|
|
*
|
|
* COPYRIGHT
|
|
* This file is distributed under the terms of the GNU General Public
|
|
* License (GPL). Copies of the GPL can be obtained from:
|
|
* ftp://prep.ai.mit.edu/pub/gnu/GPL
|
|
* Each contributing author retains all rights to their own work.
|
|
*
|
|
* (C) 1998-2004 Ben Fennema
|
|
*
|
|
* HISTORY
|
|
*
|
|
* 10/05/98 dgb Split directory operations into its own file
|
|
* Implemented directory reads via do_udf_readdir
|
|
* 10/06/98 Made directory operations work!
|
|
* 11/17/98 Rewrote directory to support ICBTAG_FLAG_AD_LONG
|
|
* 11/25/98 blf Rewrote directory handling (readdir+lookup) to support reading
|
|
* across blocks.
|
|
* 12/12/98 Split out the lookup code to namei.c. bulk of directory
|
|
* code now in directory.c:udf_fileident_read.
|
|
*/
|
|
|
|
#include "udfdecl.h"
|
|
|
|
#include <linux/string.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/bio.h>
|
|
#include <linux/iversion.h>
|
|
|
|
#include "udf_i.h"
|
|
#include "udf_sb.h"
|
|
|
|
static int udf_readdir(struct file *file, struct dir_context *ctx)
|
|
{
|
|
struct inode *dir = file_inode(file);
|
|
loff_t nf_pos, emit_pos = 0;
|
|
int flen;
|
|
unsigned char *fname = NULL;
|
|
int ret = 0;
|
|
struct super_block *sb = dir->i_sb;
|
|
bool pos_valid = false;
|
|
struct udf_fileident_iter iter;
|
|
|
|
if (ctx->pos == 0) {
|
|
if (!dir_emit_dot(file, ctx))
|
|
return 0;
|
|
ctx->pos = 1;
|
|
}
|
|
nf_pos = (ctx->pos - 1) << 2;
|
|
if (nf_pos >= dir->i_size)
|
|
goto out;
|
|
|
|
/*
|
|
* Something changed since last readdir (either lseek was called or dir
|
|
* changed)? We need to verify the position correctly points at the
|
|
* beginning of some dir entry so that the directory parsing code does
|
|
* not get confused. Since UDF does not have any reliable way of
|
|
* identifying beginning of dir entry (names are under user control),
|
|
* we need to scan the directory from the beginning.
|
|
*/
|
|
if (!inode_eq_iversion(dir, file->f_version)) {
|
|
emit_pos = nf_pos;
|
|
nf_pos = 0;
|
|
} else {
|
|
pos_valid = true;
|
|
}
|
|
|
|
fname = kmalloc(UDF_NAME_LEN, GFP_NOFS);
|
|
if (!fname) {
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
for (ret = udf_fiiter_init(&iter, dir, nf_pos);
|
|
!ret && iter.pos < dir->i_size;
|
|
ret = udf_fiiter_advance(&iter)) {
|
|
struct kernel_lb_addr tloc;
|
|
udf_pblk_t iblock;
|
|
|
|
/* Still not at offset where user asked us to read from? */
|
|
if (iter.pos < emit_pos)
|
|
continue;
|
|
|
|
/* Update file position only if we got past the current one */
|
|
pos_valid = true;
|
|
ctx->pos = (iter.pos >> 2) + 1;
|
|
|
|
if (iter.fi.fileCharacteristics & FID_FILE_CHAR_DELETED) {
|
|
if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNDELETE))
|
|
continue;
|
|
}
|
|
|
|
if (iter.fi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) {
|
|
if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNHIDE))
|
|
continue;
|
|
}
|
|
|
|
if (iter.fi.fileCharacteristics & FID_FILE_CHAR_PARENT) {
|
|
if (!dir_emit_dotdot(file, ctx))
|
|
goto out_iter;
|
|
continue;
|
|
}
|
|
|
|
flen = udf_get_filename(sb, iter.name,
|
|
iter.fi.lengthFileIdent, fname, UDF_NAME_LEN);
|
|
if (flen < 0)
|
|
continue;
|
|
|
|
tloc = lelb_to_cpu(iter.fi.icb.extLocation);
|
|
iblock = udf_get_lb_pblock(sb, &tloc, 0);
|
|
if (!dir_emit(ctx, fname, flen, iblock, DT_UNKNOWN))
|
|
goto out_iter;
|
|
}
|
|
|
|
if (!ret) {
|
|
ctx->pos = (iter.pos >> 2) + 1;
|
|
pos_valid = true;
|
|
}
|
|
out_iter:
|
|
udf_fiiter_release(&iter);
|
|
out:
|
|
if (pos_valid)
|
|
file->f_version = inode_query_iversion(dir);
|
|
kfree(fname);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* readdir and lookup functions */
|
|
const struct file_operations udf_dir_operations = {
|
|
.llseek = generic_file_llseek,
|
|
.read = generic_read_dir,
|
|
.iterate_shared = udf_readdir,
|
|
.unlocked_ioctl = udf_ioctl,
|
|
.fsync = generic_file_fsync,
|
|
};
|