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/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/fsnotify_backend.h>
#include <linux/path.h>
#include <linux/slab.h>
#include <linux/exportfs.h>
extern struct kmem_cache *fanotify_mark_cache;
extern struct kmem_cache *fanotify_fid_event_cachep;
extern struct kmem_cache *fanotify_path_event_cachep;
extern struct kmem_cache *fanotify_perm_event_cachep;
/* Possible states of the permission event */
enum {
FAN_EVENT_INIT,
FAN_EVENT_REPORTED,
FAN_EVENT_ANSWERED,
FAN_EVENT_CANCELED,
};
/*
* 3 dwords are sufficient for most local fs (64bit ino, 32bit generation).
* fh buf should be dword aligned. On 64bit arch, the ext_buf pointer is
* stored in either the first or last 2 dwords.
*/
#define FANOTIFY_INLINE_FH_LEN (3 << 2)
struct fanotify_fh {
unsigned char buf[FANOTIFY_INLINE_FH_LEN];
u8 type;
u8 len;
} __aligned(4);
static inline bool fanotify_fh_has_ext_buf(struct fanotify_fh *fh)
{
return fh->len > FANOTIFY_INLINE_FH_LEN;
}
static inline char **fanotify_fh_ext_buf_ptr(struct fanotify_fh *fh)
{
BUILD_BUG_ON(__alignof__(char *) - 4 + sizeof(char *) >
FANOTIFY_INLINE_FH_LEN);
return (char **)ALIGN((unsigned long)(fh->buf), __alignof__(char *));
}
static inline void *fanotify_fh_ext_buf(struct fanotify_fh *fh)
{
return *fanotify_fh_ext_buf_ptr(fh);
}
static inline void *fanotify_fh_buf(struct fanotify_fh *fh)
{
return fanotify_fh_has_ext_buf(fh) ? fanotify_fh_ext_buf(fh) : fh->buf;
}
/*
* Common structure for fanotify events. Concrete structs are allocated in
* fanotify_handle_event() and freed when the information is retrieved by
* userspace. The type of event determines how it was allocated, how it will
* be freed and which concrete struct it may be cast to.
*/
enum fanotify_event_type {
FANOTIFY_EVENT_TYPE_FID, /* fixed length */
FANOTIFY_EVENT_TYPE_FID_NAME, /* variable length */
FANOTIFY_EVENT_TYPE_PATH,
FANOTIFY_EVENT_TYPE_PATH_PERM,
};
struct fanotify_event {
struct fsnotify_event fse;
u32 mask;
enum fanotify_event_type type;
struct pid *pid;
};
struct fanotify_fid_event {
struct fanotify_event fae;
__kernel_fsid_t fsid;
struct fanotify_fh object_fh;
};
static inline struct fanotify_fid_event *
FANOTIFY_FE(struct fanotify_event *event)
{
return container_of(event, struct fanotify_fid_event, fae);
}
struct fanotify_name_event {
struct fanotify_event fae;
__kernel_fsid_t fsid;
struct fanotify_fh dir_fh;
u8 name_len;
char name[0];
};
static inline struct fanotify_name_event *
FANOTIFY_NE(struct fanotify_event *event)
{
return container_of(event, struct fanotify_name_event, fae);
}
static inline __kernel_fsid_t *fanotify_event_fsid(struct fanotify_event *event)
{
if (event->type == FANOTIFY_EVENT_TYPE_FID)
return &FANOTIFY_FE(event)->fsid;
else if (event->type == FANOTIFY_EVENT_TYPE_FID_NAME)
return &FANOTIFY_NE(event)->fsid;
else
return NULL;
}
static inline struct fanotify_fh *fanotify_event_object_fh(
struct fanotify_event *event)
{
if (event->type == FANOTIFY_EVENT_TYPE_FID)
return &FANOTIFY_FE(event)->object_fh;
else
return NULL;
}
static inline struct fanotify_fh *fanotify_event_dir_fh(
struct fanotify_event *event)
{
if (event->type == FANOTIFY_EVENT_TYPE_FID_NAME)
return &FANOTIFY_NE(event)->dir_fh;
else
return NULL;
}
static inline int fanotify_event_object_fh_len(struct fanotify_event *event)
{
struct fanotify_fh *fh = fanotify_event_object_fh(event);
return fh ? fh->len : 0;
}
static inline bool fanotify_event_has_name(struct fanotify_event *event)
{
return event->type == FANOTIFY_EVENT_TYPE_FID_NAME;
}
static inline int fanotify_event_name_len(struct fanotify_event *event)
{
return fanotify_event_has_name(event) ?
FANOTIFY_NE(event)->name_len : 0;
}
struct fanotify_path_event {
struct fanotify_event fae;
struct path path;
};
static inline struct fanotify_path_event *
FANOTIFY_PE(struct fanotify_event *event)
{
return container_of(event, struct fanotify_path_event, fae);
}
/*
* Structure for permission fanotify events. It gets allocated and freed in
* fanotify_handle_event() since we wait there for user response. When the
* information is retrieved by userspace the structure is moved from
* group->notification_list to group->fanotify_data.access_list to wait for
* user response.
*/
struct fanotify_perm_event {
struct fanotify_event fae;
struct path path;
unsigned short response; /* userspace answer to the event */
unsigned short state; /* state of the event */
int fd; /* fd we passed to userspace for this event */
};
static inline struct fanotify_perm_event *
FANOTIFY_PERM(struct fanotify_event *event)
{
return container_of(event, struct fanotify_perm_event, fae);
}
static inline bool fanotify_is_perm_event(u32 mask)
{
return IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS) &&
mask & FANOTIFY_PERM_EVENTS;
}
static inline struct fanotify_event *FANOTIFY_E(struct fsnotify_event *fse)
{
return container_of(fse, struct fanotify_event, fse);
}
static inline bool fanotify_event_has_path(struct fanotify_event *event)
{
return event->type == FANOTIFY_EVENT_TYPE_PATH ||
event->type == FANOTIFY_EVENT_TYPE_PATH_PERM;
}
static inline struct path *fanotify_event_path(struct fanotify_event *event)
{
if (event->type == FANOTIFY_EVENT_TYPE_PATH)
return &FANOTIFY_PE(event)->path;
else if (event->type == FANOTIFY_EVENT_TYPE_PATH_PERM)
return &FANOTIFY_PERM(event)->path;
else
return NULL;
}
struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
struct inode *inode, u32 mask,
const void *data, int data_type,
const struct qstr *file_name,
__kernel_fsid_t *fsid);
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