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	Fixed MTP to work with TWRP
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								fs/notify/fanotify/fanotify.c
									
										
									
									
									
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								fs/notify/fanotify/fanotify.c
									
										
									
									
									
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							|  | @ -0,0 +1,269 @@ | |||
| #include <linux/fanotify.h> | ||||
| #include <linux/fdtable.h> | ||||
| #include <linux/fsnotify_backend.h> | ||||
| #include <linux/init.h> | ||||
| #include <linux/jiffies.h> | ||||
| #include <linux/kernel.h> /* UINT_MAX */ | ||||
| #include <linux/mount.h> | ||||
| #include <linux/sched.h> | ||||
| #include <linux/types.h> | ||||
| #include <linux/wait.h> | ||||
| 
 | ||||
| #include "fanotify.h" | ||||
| 
 | ||||
| static bool should_merge(struct fsnotify_event *old_fsn, | ||||
| 			 struct fsnotify_event *new_fsn) | ||||
| { | ||||
| 	struct fanotify_event_info *old, *new; | ||||
| 
 | ||||
| 	pr_debug("%s: old=%p new=%p\n", __func__, old_fsn, new_fsn); | ||||
| 	old = FANOTIFY_E(old_fsn); | ||||
| 	new = FANOTIFY_E(new_fsn); | ||||
| 
 | ||||
| 	if (old_fsn->inode == new_fsn->inode && old->tgid == new->tgid && | ||||
| 	    old->path.mnt == new->path.mnt && | ||||
| 	    old->path.dentry == new->path.dentry) | ||||
| 		return true; | ||||
| 	return false; | ||||
| } | ||||
| 
 | ||||
| /* and the list better be locked by something too! */ | ||||
| static int fanotify_merge(struct list_head *list, struct fsnotify_event *event) | ||||
| { | ||||
| 	struct fsnotify_event *test_event; | ||||
| 	bool do_merge = false; | ||||
| 
 | ||||
| 	pr_debug("%s: list=%p event=%p\n", __func__, list, event); | ||||
| 
 | ||||
| #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS | ||||
| 	/*
 | ||||
| 	 * Don't merge a permission event with any other event so that we know | ||||
| 	 * the event structure we have created in fanotify_handle_event() is the | ||||
| 	 * one we should check for permission response. | ||||
| 	 */ | ||||
| 	if (event->mask & FAN_ALL_PERM_EVENTS) | ||||
| 		return 0; | ||||
| #endif | ||||
| 
 | ||||
| 	list_for_each_entry_reverse(test_event, list, list) { | ||||
| 		if (should_merge(test_event, event)) { | ||||
| 			do_merge = true; | ||||
| 			break; | ||||
| 		} | ||||
| 	} | ||||
| 
 | ||||
| 	if (!do_merge) | ||||
| 		return 0; | ||||
| 
 | ||||
| 	test_event->mask |= event->mask; | ||||
| 	return 1; | ||||
| } | ||||
| 
 | ||||
| #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS | ||||
| static int fanotify_get_response(struct fsnotify_group *group, | ||||
| 				 struct fanotify_perm_event_info *event) | ||||
| { | ||||
| 	int ret; | ||||
| 
 | ||||
| 	pr_debug("%s: group=%p event=%p\n", __func__, group, event); | ||||
| 
 | ||||
| 	wait_event(group->fanotify_data.access_waitq, event->response || | ||||
| 				atomic_read(&group->fanotify_data.bypass_perm)); | ||||
| 
 | ||||
| 	if (!event->response) {	/* bypass_perm set */ | ||||
| 		/*
 | ||||
| 		 * Event was canceled because group is being destroyed. Remove | ||||
| 		 * it from group's event list because we are responsible for | ||||
| 		 * freeing the permission event. | ||||
| 		 */ | ||||
| 		fsnotify_remove_event(group, &event->fae.fse); | ||||
| 		return 0; | ||||
| 	} | ||||
| 
 | ||||
| 	/* userspace responded, convert to something usable */ | ||||
| 	switch (event->response) { | ||||
| 	case FAN_ALLOW: | ||||
| 		ret = 0; | ||||
| 		break; | ||||
| 	case FAN_DENY: | ||||
| 	default: | ||||
| 		ret = -EPERM; | ||||
| 	} | ||||
| 	event->response = 0; | ||||
| 
 | ||||
| 	pr_debug("%s: group=%p event=%p about to return ret=%d\n", __func__, | ||||
| 		 group, event, ret); | ||||
| 	 | ||||
| 	return ret; | ||||
| } | ||||
| #endif | ||||
| 
 | ||||
| static bool fanotify_should_send_event(struct fsnotify_mark *inode_mark, | ||||
| 				       struct fsnotify_mark *vfsmnt_mark, | ||||
| 				       u32 event_mask, | ||||
| 				       void *data, int data_type) | ||||
| { | ||||
| 	__u32 marks_mask, marks_ignored_mask; | ||||
| 	struct path *path = data; | ||||
| 
 | ||||
| 	pr_debug("%s: inode_mark=%p vfsmnt_mark=%p mask=%x data=%p" | ||||
| 		 " data_type=%d\n", __func__, inode_mark, vfsmnt_mark, | ||||
| 		 event_mask, data, data_type); | ||||
| 
 | ||||
| 	/* if we don't have enough info to send an event to userspace say no */ | ||||
| 	if (data_type != FSNOTIFY_EVENT_PATH) | ||||
| 		return false; | ||||
| 
 | ||||
| 	/* sorry, fanotify only gives a damn about files and dirs */ | ||||
| 	if (!S_ISREG(path->dentry->d_inode->i_mode) && | ||||
| 	    !S_ISDIR(path->dentry->d_inode->i_mode)) | ||||
| 		return false; | ||||
| 
 | ||||
| 	if (inode_mark && vfsmnt_mark) { | ||||
| 		marks_mask = (vfsmnt_mark->mask | inode_mark->mask); | ||||
| 		marks_ignored_mask = (vfsmnt_mark->ignored_mask | inode_mark->ignored_mask); | ||||
| 	} else if (inode_mark) { | ||||
| 		/*
 | ||||
| 		 * if the event is for a child and this inode doesn't care about | ||||
| 		 * events on the child, don't send it! | ||||
| 		 */ | ||||
| 		if ((event_mask & FS_EVENT_ON_CHILD) && | ||||
| 		    !(inode_mark->mask & FS_EVENT_ON_CHILD)) | ||||
| 			return false; | ||||
| 		marks_mask = inode_mark->mask; | ||||
| 		marks_ignored_mask = inode_mark->ignored_mask; | ||||
| 	} else if (vfsmnt_mark) { | ||||
| 		marks_mask = vfsmnt_mark->mask; | ||||
| 		marks_ignored_mask = vfsmnt_mark->ignored_mask; | ||||
| 	} else { | ||||
| 		BUG(); | ||||
| 	} | ||||
| 
 | ||||
| 	if (S_ISDIR(path->dentry->d_inode->i_mode) && | ||||
| 	    (marks_ignored_mask & FS_ISDIR)) | ||||
| 		return false; | ||||
| 
 | ||||
| 	if (event_mask & marks_mask & ~marks_ignored_mask) | ||||
| 		return true; | ||||
| 
 | ||||
| 	return false; | ||||
| } | ||||
| 
 | ||||
| struct fanotify_event_info *fanotify_alloc_event(struct inode *inode, u32 mask, | ||||
| 						 struct path *path) | ||||
| { | ||||
| 	struct fanotify_event_info *event; | ||||
| 
 | ||||
| #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS | ||||
| 	if (mask & FAN_ALL_PERM_EVENTS) { | ||||
| 		struct fanotify_perm_event_info *pevent; | ||||
| 
 | ||||
| 		pevent = kmem_cache_alloc(fanotify_perm_event_cachep, | ||||
| 					  GFP_KERNEL); | ||||
| 		if (!pevent) | ||||
| 			return NULL; | ||||
| 		event = &pevent->fae; | ||||
| 		pevent->response = 0; | ||||
| 		goto init; | ||||
| 	} | ||||
| #endif | ||||
| 	event = kmem_cache_alloc(fanotify_event_cachep, GFP_KERNEL); | ||||
| 	if (!event) | ||||
| 		return NULL; | ||||
| init: __maybe_unused | ||||
| 	fsnotify_init_event(&event->fse, inode, mask); | ||||
| 	event->tgid = get_pid(task_tgid(current)); | ||||
| 	if (path) { | ||||
| 		event->path = *path; | ||||
| 		path_get(&event->path); | ||||
| 	} else { | ||||
| 		event->path.mnt = NULL; | ||||
| 		event->path.dentry = NULL; | ||||
| 	} | ||||
| 	return event; | ||||
| } | ||||
| 
 | ||||
| static int fanotify_handle_event(struct fsnotify_group *group, | ||||
| 				 struct inode *inode, | ||||
| 				 struct fsnotify_mark *inode_mark, | ||||
| 				 struct fsnotify_mark *fanotify_mark, | ||||
| 				 u32 mask, void *data, int data_type, | ||||
| 				 const unsigned char *file_name, u32 cookie) | ||||
| { | ||||
| 	int ret = 0; | ||||
| 	struct fanotify_event_info *event; | ||||
| 	struct fsnotify_event *fsn_event; | ||||
| 
 | ||||
| 	BUILD_BUG_ON(FAN_ACCESS != FS_ACCESS); | ||||
| 	BUILD_BUG_ON(FAN_MODIFY != FS_MODIFY); | ||||
| 	BUILD_BUG_ON(FAN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE); | ||||
| 	BUILD_BUG_ON(FAN_CLOSE_WRITE != FS_CLOSE_WRITE); | ||||
| 	BUILD_BUG_ON(FAN_OPEN != FS_OPEN); | ||||
| 	BUILD_BUG_ON(FAN_EVENT_ON_CHILD != FS_EVENT_ON_CHILD); | ||||
| 	BUILD_BUG_ON(FAN_Q_OVERFLOW != FS_Q_OVERFLOW); | ||||
| 	BUILD_BUG_ON(FAN_OPEN_PERM != FS_OPEN_PERM); | ||||
| 	BUILD_BUG_ON(FAN_ACCESS_PERM != FS_ACCESS_PERM); | ||||
| 	BUILD_BUG_ON(FAN_ONDIR != FS_ISDIR); | ||||
| 
 | ||||
| 	if (!fanotify_should_send_event(inode_mark, fanotify_mark, mask, data, | ||||
| 					data_type)) | ||||
| 		return 0; | ||||
| 
 | ||||
| 	pr_debug("%s: group=%p inode=%p mask=%x\n", __func__, group, inode, | ||||
| 		 mask); | ||||
| 
 | ||||
| 	event = fanotify_alloc_event(inode, mask, data); | ||||
| 	if (unlikely(!event)) | ||||
| 		return -ENOMEM; | ||||
| 
 | ||||
| 	fsn_event = &event->fse; | ||||
| 	ret = fsnotify_add_event(group, fsn_event, fanotify_merge); | ||||
| 	if (ret) { | ||||
| 		/* Permission events shouldn't be merged */ | ||||
| 		BUG_ON(ret == 1 && mask & FAN_ALL_PERM_EVENTS); | ||||
| 		/* Our event wasn't used in the end. Free it. */ | ||||
| 		fsnotify_destroy_event(group, fsn_event); | ||||
| 
 | ||||
| 		return 0; | ||||
| 	} | ||||
| 
 | ||||
| #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS | ||||
| 	if (mask & FAN_ALL_PERM_EVENTS) { | ||||
| 		ret = fanotify_get_response(group, FANOTIFY_PE(fsn_event)); | ||||
| 		fsnotify_destroy_event(group, fsn_event); | ||||
| 	} | ||||
| #endif | ||||
| 	return ret; | ||||
| } | ||||
| 
 | ||||
| static void fanotify_free_group_priv(struct fsnotify_group *group) | ||||
| { | ||||
| 	struct user_struct *user; | ||||
| 
 | ||||
| 	user = group->fanotify_data.user; | ||||
| 	atomic_dec(&user->fanotify_listeners); | ||||
| 	free_uid(user); | ||||
| } | ||||
| 
 | ||||
| static void fanotify_free_event(struct fsnotify_event *fsn_event) | ||||
| { | ||||
| 	struct fanotify_event_info *event; | ||||
| 
 | ||||
| 	event = FANOTIFY_E(fsn_event); | ||||
| 	path_put(&event->path); | ||||
| 	put_pid(event->tgid); | ||||
| #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS | ||||
| 	if (fsn_event->mask & FAN_ALL_PERM_EVENTS) { | ||||
| 		kmem_cache_free(fanotify_perm_event_cachep, | ||||
| 				FANOTIFY_PE(fsn_event)); | ||||
| 		return; | ||||
| 	} | ||||
| #endif | ||||
| 	kmem_cache_free(fanotify_event_cachep, event); | ||||
| } | ||||
| 
 | ||||
| const struct fsnotify_ops fanotify_fsnotify_ops = { | ||||
| 	.handle_event = fanotify_handle_event, | ||||
| 	.free_group_priv = fanotify_free_group_priv, | ||||
| 	.free_event = fanotify_free_event, | ||||
| }; | ||||
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