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ab9953ff | 1 | // SPDX-License-Identifier: GPL-2.0 |
1ffaa640 HB |
2 | /* |
3 | * Deliver z/VM CP special messages (SMSG) as uevents. | |
4 | * | |
5 | * The driver registers for z/VM CP special messages with the | |
6 | * "APP" prefix. Incoming messages are delivered to user space | |
7 | * as uevents. | |
8 | * | |
9 | * Copyright IBM Corp. 2010 | |
10 | * Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com> | |
11 | * | |
12 | */ | |
13 | #define KMSG_COMPONENT "smsgiucv_app" | |
14 | #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt | |
15 | ||
16 | #include <linux/ctype.h> | |
17 | #include <linux/err.h> | |
18 | #include <linux/device.h> | |
19 | #include <linux/list.h> | |
20 | #include <linux/kobject.h> | |
21 | #include <linux/module.h> | |
5a0e3ad6 | 22 | #include <linux/slab.h> |
1ffaa640 HB |
23 | #include <linux/spinlock.h> |
24 | #include <linux/workqueue.h> | |
25 | #include <net/iucv/iucv.h> | |
26 | #include "smsgiucv.h" | |
27 | ||
28 | /* prefix used for SMSG registration */ | |
29 | #define SMSG_PREFIX "APP" | |
30 | ||
31 | /* SMSG related uevent environment variables */ | |
32 | #define ENV_SENDER_STR "SMSG_SENDER=" | |
33 | #define ENV_SENDER_LEN (strlen(ENV_SENDER_STR) + 8 + 1) | |
34 | #define ENV_PREFIX_STR "SMSG_ID=" | |
35 | #define ENV_PREFIX_LEN (strlen(ENV_PREFIX_STR) + \ | |
36 | strlen(SMSG_PREFIX) + 1) | |
37 | #define ENV_TEXT_STR "SMSG_TEXT=" | |
38 | #define ENV_TEXT_LEN(msg) (strlen(ENV_TEXT_STR) + strlen((msg)) + 1) | |
39 | ||
40 | /* z/VM user ID which is permitted to send SMSGs | |
41 | * If the value is undefined or empty (""), special messages are | |
42 | * accepted from any z/VM user ID. */ | |
43 | static char *sender; | |
44 | module_param(sender, charp, 0400); | |
45 | MODULE_PARM_DESC(sender, "z/VM user ID from which CP SMSGs are accepted"); | |
46 | ||
47 | /* SMSG device representation */ | |
48 | static struct device *smsg_app_dev; | |
49 | ||
50 | /* list element for queuing received messages for delivery */ | |
51 | struct smsg_app_event { | |
52 | struct list_head list; | |
53 | char *buf; | |
54 | char *envp[4]; | |
55 | }; | |
56 | ||
57 | /* queue for outgoing uevents */ | |
58 | static LIST_HEAD(smsg_event_queue); | |
59 | static DEFINE_SPINLOCK(smsg_event_queue_lock); | |
60 | ||
61 | static void smsg_app_event_free(struct smsg_app_event *ev) | |
62 | { | |
63 | kfree(ev->buf); | |
64 | kfree(ev); | |
65 | } | |
66 | ||
67 | static struct smsg_app_event *smsg_app_event_alloc(const char *from, | |
68 | const char *msg) | |
69 | { | |
70 | struct smsg_app_event *ev; | |
71 | ||
72 | ev = kzalloc(sizeof(*ev), GFP_ATOMIC); | |
73 | if (!ev) | |
74 | return NULL; | |
75 | ||
76 | ev->buf = kzalloc(ENV_SENDER_LEN + ENV_PREFIX_LEN + | |
77 | ENV_TEXT_LEN(msg), GFP_ATOMIC); | |
78 | if (!ev->buf) { | |
79 | kfree(ev); | |
80 | return NULL; | |
81 | } | |
82 | ||
83 | /* setting up environment pointers into buf */ | |
84 | ev->envp[0] = ev->buf; | |
85 | ev->envp[1] = ev->envp[0] + ENV_SENDER_LEN; | |
86 | ev->envp[2] = ev->envp[1] + ENV_PREFIX_LEN; | |
87 | ev->envp[3] = NULL; | |
88 | ||
89 | /* setting up environment: sender, prefix name, and message text */ | |
90 | snprintf(ev->envp[0], ENV_SENDER_LEN, ENV_SENDER_STR "%s", from); | |
91 | snprintf(ev->envp[1], ENV_PREFIX_LEN, ENV_PREFIX_STR "%s", SMSG_PREFIX); | |
92 | snprintf(ev->envp[2], ENV_TEXT_LEN(msg), ENV_TEXT_STR "%s", msg); | |
93 | ||
94 | return ev; | |
95 | } | |
96 | ||
97 | static void smsg_event_work_fn(struct work_struct *work) | |
98 | { | |
99 | LIST_HEAD(event_queue); | |
100 | struct smsg_app_event *p, *n; | |
101 | struct device *dev; | |
102 | ||
103 | dev = get_device(smsg_app_dev); | |
104 | if (!dev) | |
105 | return; | |
106 | ||
107 | spin_lock_bh(&smsg_event_queue_lock); | |
108 | list_splice_init(&smsg_event_queue, &event_queue); | |
109 | spin_unlock_bh(&smsg_event_queue_lock); | |
110 | ||
111 | list_for_each_entry_safe(p, n, &event_queue, list) { | |
112 | list_del(&p->list); | |
113 | kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, p->envp); | |
114 | smsg_app_event_free(p); | |
115 | } | |
116 | ||
117 | put_device(dev); | |
118 | } | |
119 | static DECLARE_WORK(smsg_event_work, smsg_event_work_fn); | |
120 | ||
121 | static void smsg_app_callback(const char *from, char *msg) | |
122 | { | |
123 | struct smsg_app_event *se; | |
124 | ||
125 | /* check if the originating z/VM user ID matches | |
126 | * the configured sender. */ | |
127 | if (sender && strlen(sender) > 0 && strcmp(from, sender) != 0) | |
128 | return; | |
129 | ||
130 | /* get start of message text (skip prefix and leading blanks) */ | |
131 | msg += strlen(SMSG_PREFIX); | |
132 | while (*msg && isspace(*msg)) | |
133 | msg++; | |
134 | if (*msg == '\0') | |
135 | return; | |
136 | ||
137 | /* allocate event list element and its environment */ | |
138 | se = smsg_app_event_alloc(from, msg); | |
139 | if (!se) | |
140 | return; | |
141 | ||
142 | /* queue event and schedule work function */ | |
143 | spin_lock(&smsg_event_queue_lock); | |
144 | list_add_tail(&se->list, &smsg_event_queue); | |
145 | spin_unlock(&smsg_event_queue_lock); | |
146 | ||
147 | schedule_work(&smsg_event_work); | |
148 | return; | |
149 | } | |
150 | ||
151 | static int __init smsgiucv_app_init(void) | |
152 | { | |
153 | struct device_driver *smsgiucv_drv; | |
154 | int rc; | |
155 | ||
156 | if (!MACHINE_IS_VM) | |
157 | return -ENODEV; | |
158 | ||
159 | smsg_app_dev = kzalloc(sizeof(*smsg_app_dev), GFP_KERNEL); | |
160 | if (!smsg_app_dev) | |
161 | return -ENOMEM; | |
162 | ||
163 | smsgiucv_drv = driver_find(SMSGIUCV_DRV_NAME, &iucv_bus); | |
164 | if (!smsgiucv_drv) { | |
165 | kfree(smsg_app_dev); | |
166 | return -ENODEV; | |
167 | } | |
168 | ||
169 | rc = dev_set_name(smsg_app_dev, KMSG_COMPONENT); | |
170 | if (rc) { | |
171 | kfree(smsg_app_dev); | |
fde25a9b | 172 | goto fail; |
1ffaa640 HB |
173 | } |
174 | smsg_app_dev->bus = &iucv_bus; | |
175 | smsg_app_dev->parent = iucv_root; | |
176 | smsg_app_dev->release = (void (*)(struct device *)) kfree; | |
177 | smsg_app_dev->driver = smsgiucv_drv; | |
178 | rc = device_register(smsg_app_dev); | |
179 | if (rc) { | |
180 | put_device(smsg_app_dev); | |
fde25a9b | 181 | goto fail; |
1ffaa640 HB |
182 | } |
183 | ||
41b42876 HB |
184 | /* convert sender to uppercase characters */ |
185 | if (sender) { | |
186 | int len = strlen(sender); | |
187 | while (len--) | |
188 | sender[len] = toupper(sender[len]); | |
189 | } | |
190 | ||
1ffaa640 HB |
191 | /* register with the smsgiucv device driver */ |
192 | rc = smsg_register_callback(SMSG_PREFIX, smsg_app_callback); | |
193 | if (rc) { | |
194 | device_unregister(smsg_app_dev); | |
fde25a9b | 195 | goto fail; |
1ffaa640 HB |
196 | } |
197 | ||
198 | rc = 0; | |
fde25a9b | 199 | fail: |
1ffaa640 HB |
200 | return rc; |
201 | } | |
202 | module_init(smsgiucv_app_init); | |
203 | ||
204 | static void __exit smsgiucv_app_exit(void) | |
205 | { | |
206 | /* unregister callback */ | |
207 | smsg_unregister_callback(SMSG_PREFIX, smsg_app_callback); | |
208 | ||
209 | /* cancel pending work and flush any queued event work */ | |
210 | cancel_work_sync(&smsg_event_work); | |
211 | smsg_event_work_fn(&smsg_event_work); | |
212 | ||
213 | device_unregister(smsg_app_dev); | |
214 | } | |
215 | module_exit(smsgiucv_app_exit); | |
216 | ||
217 | MODULE_LICENSE("GPL v2"); | |
218 | MODULE_DESCRIPTION("Deliver z/VM CP SMSG as uevents"); | |
219 | MODULE_AUTHOR("Hendrik Brueckner <brueckner@linux.vnet.ibm.com>"); |