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[readdir] convert efs 

* sanity checks belong before risky operation, not after it
* don't quit as soon as we'd found an entry

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2013-05-16 01:41:10 -04:00
parent 52018855e6
commit 7aa123a0dc
1 changed files with 33 additions and 42 deletions
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75
fs/efs/dir.c
View File

@ -7,40 +7,38 @@
#include <linux/buffer_head.h>
#include "efs.h"
static int efs_readdir(struct file *, void *, filldir_t);
static int efs_readdir(struct file *, struct dir_context *);
const struct file_operations efs_dir_operations = {
.llseek = generic_file_llseek,
.read = generic_read_dir,
.readdir = efs_readdir,
.iterate = efs_readdir,
};
const struct inode_operations efs_dir_inode_operations = {
.lookup = efs_lookup,
};
static int efs_readdir(struct file *filp, void *dirent, filldir_t filldir) {
struct inode *inode = file_inode(filp);
struct buffer_head *bh;
struct efs_dir *dirblock;
struct efs_dentry *dirslot;
efs_ino_t inodenum;
static int efs_readdir(struct file *file, struct dir_context *ctx)
{
struct inode *inode = file_inode(file);
efs_block_t block;
int slot, namelen;
char *nameptr;
int slot;
if (inode->i_size & (EFS_DIRBSIZE-1))
printk(KERN_WARNING "EFS: WARNING: readdir(): directory size not a multiple of EFS_DIRBSIZE\n");
/* work out where this entry can be found */
block = filp->f_pos >> EFS_DIRBSIZE_BITS;
block = ctx->pos >> EFS_DIRBSIZE_BITS;
/* each block contains at most 256 slots */
slot = filp->f_pos & 0xff;
slot = ctx->pos & 0xff;
/* look at all blocks */
while (block < inode->i_blocks) {
struct efs_dir *dirblock;
struct buffer_head *bh;
/* read the dir block */
bh = sb_bread(inode->i_sb, efs_bmap(inode, block));
@ -57,11 +55,14 @@ static int efs_readdir(struct file *filp, void *dirent, filldir_t filldir) {
break;
}
while (slot < dirblock->slots) {
if (dirblock->space[slot] == 0) {
slot++;
for (; slot < dirblock->slots; slot++) {
struct efs_dentry *dirslot;
efs_ino_t inodenum;
const char *nameptr;
int namelen;
if (dirblock->space[slot] == 0)
continue;
}
dirslot = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot));
@ -72,39 +73,29 @@ static int efs_readdir(struct file *filp, void *dirent, filldir_t filldir) {
#ifdef DEBUG
printk(KERN_DEBUG "EFS: readdir(): block %d slot %d/%d: inode %u, name \"%s\", namelen %u\n", block, slot, dirblock->slots-1, inodenum, nameptr, namelen);
#endif
if (namelen > 0) {
/* found the next entry */
filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot;
if (!namelen)
continue;
/* found the next entry */
ctx->pos = (block << EFS_DIRBSIZE_BITS) | slot;
/* copy filename and data in dirslot */
filldir(dirent, nameptr, namelen, filp->f_pos, inodenum, DT_UNKNOWN);
/* sanity check */
if (nameptr - (char *) dirblock + namelen > EFS_DIRBSIZE) {
printk(KERN_WARNING "EFS: directory entry %d exceeds directory block\n", slot);
slot++;
continue;
}
/* store position of next slot */
if (++slot == dirblock->slots) {
slot = 0;
block++;
}
brelse(bh);
filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot;
goto out;
/* sanity check */
if (nameptr - (char *) dirblock + namelen > EFS_DIRBSIZE) {
printk(KERN_WARNING "EFS: directory entry %d exceeds directory block\n", slot);
continue;
}
/* copy filename and data in dirslot */
if (!dir_emit(ctx, nameptr, namelen, inodenum, DT_UNKNOWN)) {
brelse(bh);
return 0;
}
slot++;
}
brelse(bh);
slot = 0;
block++;
}
filp->f_pos = (block << EFS_DIRBSIZE_BITS) | slot;
out:
ctx->pos = (block << EFS_DIRBSIZE_BITS) | slot;
return 0;
}