53853995c6
Both dir.c and namei.c need to perform the same work to figure out a directory entry's name and size. Extract this into a helper for use in the next patch. Acked-by: Anders Larsen <al@alarsen.net> Link: https://lore.kernel.org/r/20231130205120.3642477-1-keescook@chromium.org Signed-off-by: Kees Cook <keescook@chromium.org>
107 lines
3.0 KiB
C
107 lines
3.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#include <linux/fs.h>
|
|
#include <linux/qnx4_fs.h>
|
|
|
|
#define QNX4_DEBUG 0
|
|
|
|
#if QNX4_DEBUG
|
|
#define QNX4DEBUG(X) printk X
|
|
#else
|
|
#define QNX4DEBUG(X) (void) 0
|
|
#endif
|
|
|
|
struct qnx4_sb_info {
|
|
unsigned int Version; /* may be useful */
|
|
struct qnx4_inode_entry *BitMap; /* useful */
|
|
};
|
|
|
|
struct qnx4_inode_info {
|
|
struct qnx4_inode_entry raw;
|
|
loff_t mmu_private;
|
|
struct inode vfs_inode;
|
|
};
|
|
|
|
extern struct inode *qnx4_iget(struct super_block *, unsigned long);
|
|
extern struct dentry *qnx4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags);
|
|
extern unsigned long qnx4_count_free_blocks(struct super_block *sb);
|
|
extern unsigned long qnx4_block_map(struct inode *inode, long iblock);
|
|
|
|
extern const struct inode_operations qnx4_dir_inode_operations;
|
|
extern const struct file_operations qnx4_dir_operations;
|
|
extern int qnx4_is_free(struct super_block *sb, long block);
|
|
|
|
static inline struct qnx4_sb_info *qnx4_sb(struct super_block *sb)
|
|
{
|
|
return sb->s_fs_info;
|
|
}
|
|
|
|
static inline struct qnx4_inode_info *qnx4_i(struct inode *inode)
|
|
{
|
|
return container_of(inode, struct qnx4_inode_info, vfs_inode);
|
|
}
|
|
|
|
static inline struct qnx4_inode_entry *qnx4_raw_inode(struct inode *inode)
|
|
{
|
|
return &qnx4_i(inode)->raw;
|
|
}
|
|
|
|
/*
|
|
* A qnx4 directory entry is an inode entry or link info
|
|
* depending on the status field in the last byte. The
|
|
* first byte is where the name start either way, and a
|
|
* zero means it's empty.
|
|
*
|
|
* Also, due to a bug in gcc, we don't want to use the
|
|
* real (differently sized) name arrays in the inode and
|
|
* link entries, but always the 'de_name[]' one in the
|
|
* fake struct entry.
|
|
*
|
|
* See
|
|
*
|
|
* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578#c6
|
|
*
|
|
* for details, but basically gcc will take the size of the
|
|
* 'name' array from one of the used union entries randomly.
|
|
*
|
|
* This use of 'de_name[]' (48 bytes) avoids the false positive
|
|
* warnings that would happen if gcc decides to use 'inode.di_name'
|
|
* (16 bytes) even when the pointer and size were to come from
|
|
* 'link.dl_name' (48 bytes).
|
|
*
|
|
* In all cases the actual name pointer itself is the same, it's
|
|
* only the gcc internal 'what is the size of this field' logic
|
|
* that can get confused.
|
|
*/
|
|
union qnx4_directory_entry {
|
|
struct {
|
|
const char de_name[48];
|
|
u8 de_pad[15];
|
|
u8 de_status;
|
|
};
|
|
struct qnx4_inode_entry inode;
|
|
struct qnx4_link_info link;
|
|
};
|
|
|
|
static inline const char *get_entry_fname(union qnx4_directory_entry *de,
|
|
int *size)
|
|
{
|
|
/* Make sure the status byte is in the same place for all structs. */
|
|
BUILD_BUG_ON(offsetof(struct qnx4_inode_entry, di_status) !=
|
|
offsetof(struct qnx4_link_info, dl_status));
|
|
BUILD_BUG_ON(offsetof(struct qnx4_inode_entry, di_status) !=
|
|
offsetof(union qnx4_directory_entry, de_status));
|
|
|
|
if (!de->de_name[0])
|
|
return NULL;
|
|
if (!(de->de_status & (QNX4_FILE_USED|QNX4_FILE_LINK)))
|
|
return NULL;
|
|
if (!(de->de_status & QNX4_FILE_LINK))
|
|
*size = sizeof(de->inode.di_fname);
|
|
else
|
|
*size = sizeof(de->link.dl_fname);
|
|
|
|
*size = strnlen(de->de_name, *size);
|
|
|
|
return de->de_name;
|
|
}
|