1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Device Mapper Uevent Support (dm-uevent)
4 *
5 * Copyright IBM Corporation, 2007
6 *	Author: Mike Anderson <andmike@linux.vnet.ibm.com>
7 */
8#include <linux/list.h>
9#include <linux/slab.h>
10#include <linux/kobject.h>
11#include <linux/dm-ioctl.h>
12#include <linux/export.h>
13
14#include "dm.h"
15#include "dm-uevent.h"
16
17#define DM_MSG_PREFIX "uevent"
18
19static const struct {
20	enum dm_uevent_type type;
21	enum kobject_action action;
22	char *name;
23} _dm_uevent_type_names[] = {
24	{DM_UEVENT_PATH_FAILED, KOBJ_CHANGE, "PATH_FAILED"},
25	{DM_UEVENT_PATH_REINSTATED, KOBJ_CHANGE, "PATH_REINSTATED"},
26};
27
28static struct kmem_cache *_dm_event_cache;
29
30struct dm_uevent {
31	struct mapped_device *md;
32	enum kobject_action action;
33	struct kobj_uevent_env ku_env;
34	struct list_head elist;
35	char name[DM_NAME_LEN];
36	char uuid[DM_UUID_LEN];
37};
38
39static void dm_uevent_free(struct dm_uevent *event)
40{
41	kmem_cache_free(_dm_event_cache, event);
42}
43
44static struct dm_uevent *dm_uevent_alloc(struct mapped_device *md)
45{
46	struct dm_uevent *event;
47
48	event = kmem_cache_zalloc(_dm_event_cache, GFP_ATOMIC);
49	if (!event)
50		return NULL;
51
52	INIT_LIST_HEAD(&event->elist);
53	event->md = md;
54
55	return event;
56}
57
58static struct dm_uevent *dm_build_path_uevent(struct mapped_device *md,
59					      struct dm_target *ti,
60					      enum kobject_action action,
61					      const char *dm_action,
62					      const char *path,
63					      unsigned int nr_valid_paths)
64{
65	struct dm_uevent *event;
66
67	event = dm_uevent_alloc(md);
68	if (!event) {
69		DMERR("%s: dm_uevent_alloc() failed", __func__);
70		goto err_nomem;
71	}
72
73	event->action = action;
74
75	if (add_uevent_var(&event->ku_env, "DM_TARGET=%s", ti->type->name)) {
76		DMERR("%s: add_uevent_var() for DM_TARGET failed",
77		      __func__);
78		goto err_add;
79	}
80
81	if (add_uevent_var(&event->ku_env, "DM_ACTION=%s", dm_action)) {
82		DMERR("%s: add_uevent_var() for DM_ACTION failed",
83		      __func__);
84		goto err_add;
85	}
86
87	if (add_uevent_var(&event->ku_env, "DM_SEQNUM=%u",
88			   dm_next_uevent_seq(md))) {
89		DMERR("%s: add_uevent_var() for DM_SEQNUM failed",
90		      __func__);
91		goto err_add;
92	}
93
94	if (add_uevent_var(&event->ku_env, "DM_PATH=%s", path)) {
95		DMERR("%s: add_uevent_var() for DM_PATH failed", __func__);
96		goto err_add;
97	}
98
99	if (add_uevent_var(&event->ku_env, "DM_NR_VALID_PATHS=%d",
100			   nr_valid_paths)) {
101		DMERR("%s: add_uevent_var() for DM_NR_VALID_PATHS failed",
102		      __func__);
103		goto err_add;
104	}
105
106	return event;
107
108err_add:
109	dm_uevent_free(event);
110err_nomem:
111	return ERR_PTR(-ENOMEM);
112}
113
114/**
115 * dm_send_uevents - send uevents for given list
116 *
117 * @events:	list of events to send
118 * @kobj:	kobject generating event
119 *
120 */
121void dm_send_uevents(struct list_head *events, struct kobject *kobj)
122{
123	int r;
124	struct dm_uevent *event, *next;
125
126	list_for_each_entry_safe(event, next, events, elist) {
127		list_del_init(&event->elist);
128
129		/*
130		 * When a device is being removed this copy fails and we
131		 * discard these unsent events.
132		 */
133		if (dm_copy_name_and_uuid(event->md, event->name,
134					  event->uuid)) {
135			DMINFO("%s: skipping sending uevent for lost device",
136			       __func__);
137			goto uevent_free;
138		}
139
140		if (add_uevent_var(&event->ku_env, "DM_NAME=%s", event->name)) {
141			DMERR("%s: add_uevent_var() for DM_NAME failed",
142			      __func__);
143			goto uevent_free;
144		}
145
146		if (add_uevent_var(&event->ku_env, "DM_UUID=%s", event->uuid)) {
147			DMERR("%s: add_uevent_var() for DM_UUID failed",
148			      __func__);
149			goto uevent_free;
150		}
151
152		r = kobject_uevent_env(kobj, event->action, event->ku_env.envp);
153		if (r)
154			DMERR("%s: kobject_uevent_env failed", __func__);
155uevent_free:
156		dm_uevent_free(event);
157	}
158}
159EXPORT_SYMBOL_GPL(dm_send_uevents);
160
161/**
162 * dm_path_uevent - called to create a new path event and queue it
163 *
164 * @event_type:	path event type enum
165 * @ti:			pointer to a dm_target
166 * @path:		string containing pathname
167 * @nr_valid_paths:	number of valid paths remaining
168 *
169 */
170void dm_path_uevent(enum dm_uevent_type event_type, struct dm_target *ti,
171		   const char *path, unsigned int nr_valid_paths)
172{
173	struct mapped_device *md = dm_table_get_md(ti->table);
174	struct dm_uevent *event;
175
176	if (event_type >= ARRAY_SIZE(_dm_uevent_type_names)) {
177		DMERR("%s: Invalid event_type %d", __func__, event_type);
178		return;
179	}
180
181	event = dm_build_path_uevent(md, ti,
182				     _dm_uevent_type_names[event_type].action,
183				     _dm_uevent_type_names[event_type].name,
184				     path, nr_valid_paths);
185	if (IS_ERR(event))
186		return;
187
188	dm_uevent_add(md, &event->elist);
189}
190EXPORT_SYMBOL_GPL(dm_path_uevent);
191
192int dm_uevent_init(void)
193{
194	_dm_event_cache = KMEM_CACHE(dm_uevent, 0);
195	if (!_dm_event_cache)
196		return -ENOMEM;
197
198	DMINFO("version 1.0.3");
199
200	return 0;
201}
202
203void dm_uevent_exit(void)
204{
205	kmem_cache_destroy(_dm_event_cache);
206}
207