linux-stable/fs/udf/dir.c
Jan Kara 979a6e28dd udf: Get rid of 0-length arrays in struct fileIdentDesc
Get rid of 0-length arrays in struct fileIdentDesc. This requires a bit
of cleaning up as the second variable length array in this structure is
often used and the code abuses the fact that the first two arrays have
the same type and offset in struct fileIdentDesc.

Signed-off-by: Jan Kara <jack@suse.cz>
2021-08-11 16:54:44 +02:00

208 lines
5.2 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 "udf_i.h"
#include "udf_sb.h"
static int udf_readdir(struct file *file, struct dir_context *ctx)
{
struct inode *dir = file_inode(file);
struct udf_inode_info *iinfo = UDF_I(dir);
struct udf_fileident_bh fibh = { .sbh = NULL, .ebh = NULL};
struct fileIdentDesc *fi = NULL;
struct fileIdentDesc cfi;
udf_pblk_t block, iblock;
loff_t nf_pos;
int flen;
unsigned char *fname = NULL, *copy_name = NULL;
unsigned char *nameptr;
uint16_t liu;
uint8_t lfi;
loff_t size = udf_ext0_offset(dir) + dir->i_size;
struct buffer_head *tmp, *bha[16];
struct kernel_lb_addr eloc;
uint32_t elen;
sector_t offset;
int i, num, ret = 0;
struct extent_position epos = { NULL, 0, {0, 0} };
struct super_block *sb = dir->i_sb;
if (ctx->pos == 0) {
if (!dir_emit_dot(file, ctx))
return 0;
ctx->pos = 1;
}
nf_pos = (ctx->pos - 1) << 2;
if (nf_pos >= size)
goto out;
fname = kmalloc(UDF_NAME_LEN, GFP_NOFS);
if (!fname) {
ret = -ENOMEM;
goto out;
}
if (nf_pos == 0)
nf_pos = udf_ext0_offset(dir);
fibh.soffset = fibh.eoffset = nf_pos & (sb->s_blocksize - 1);
if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
if (inode_bmap(dir, nf_pos >> sb->s_blocksize_bits,
&epos, &eloc, &elen, &offset)
!= (EXT_RECORDED_ALLOCATED >> 30)) {
ret = -ENOENT;
goto out;
}
block = udf_get_lb_pblock(sb, &eloc, offset);
if ((++offset << sb->s_blocksize_bits) < elen) {
if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
epos.offset -= sizeof(struct short_ad);
else if (iinfo->i_alloc_type ==
ICBTAG_FLAG_AD_LONG)
epos.offset -= sizeof(struct long_ad);
} else {
offset = 0;
}
if (!(fibh.sbh = fibh.ebh = udf_tread(sb, block))) {
ret = -EIO;
goto out;
}
if (!(offset & ((16 >> (sb->s_blocksize_bits - 9)) - 1))) {
i = 16 >> (sb->s_blocksize_bits - 9);
if (i + offset > (elen >> sb->s_blocksize_bits))
i = (elen >> sb->s_blocksize_bits) - offset;
for (num = 0; i > 0; i--) {
block = udf_get_lb_pblock(sb, &eloc, offset + i);
tmp = udf_tgetblk(sb, block);
if (tmp && !buffer_uptodate(tmp) && !buffer_locked(tmp))
bha[num++] = tmp;
else
brelse(tmp);
}
if (num) {
ll_rw_block(REQ_OP_READ, REQ_RAHEAD, num, bha);
for (i = 0; i < num; i++)
brelse(bha[i]);
}
}
}
while (nf_pos < size) {
struct kernel_lb_addr tloc;
ctx->pos = (nf_pos >> 2) + 1;
fi = udf_fileident_read(dir, &nf_pos, &fibh, &cfi, &epos, &eloc,
&elen, &offset);
if (!fi)
goto out;
liu = le16_to_cpu(cfi.lengthOfImpUse);
lfi = cfi.lengthFileIdent;
if (fibh.sbh == fibh.ebh) {
nameptr = udf_get_fi_ident(fi);
} else {
int poffset; /* Unpaded ending offset */
poffset = fibh.soffset + sizeof(struct fileIdentDesc) + liu + lfi;
if (poffset >= lfi) {
nameptr = (char *)(fibh.ebh->b_data + poffset - lfi);
} else {
if (!copy_name) {
copy_name = kmalloc(UDF_NAME_LEN,
GFP_NOFS);
if (!copy_name) {
ret = -ENOMEM;
goto out;
}
}
nameptr = copy_name;
memcpy(nameptr, udf_get_fi_ident(fi),
lfi - poffset);
memcpy(nameptr + lfi - poffset,
fibh.ebh->b_data, poffset);
}
}
if ((cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) != 0) {
if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNDELETE))
continue;
}
if ((cfi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) != 0) {
if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNHIDE))
continue;
}
if (cfi.fileCharacteristics & FID_FILE_CHAR_PARENT) {
if (!dir_emit_dotdot(file, ctx))
goto out;
continue;
}
flen = udf_get_filename(sb, nameptr, lfi, fname, UDF_NAME_LEN);
if (flen < 0)
continue;
tloc = lelb_to_cpu(cfi.icb.extLocation);
iblock = udf_get_lb_pblock(sb, &tloc, 0);
if (!dir_emit(ctx, fname, flen, iblock, DT_UNKNOWN))
goto out;
} /* end while */
ctx->pos = (nf_pos >> 2) + 1;
out:
if (fibh.sbh != fibh.ebh)
brelse(fibh.ebh);
brelse(fibh.sbh);
brelse(epos.bh);
kfree(fname);
kfree(copy_name);
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,
};