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