1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * IUCV special message driver
4 *
5 * Copyright IBM Corp. 2003, 2009
6 *
7 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
8 */
9
10#include <linux/module.h>
11#include <linux/init.h>
12#include <linux/errno.h>
13#include <linux/device.h>
14#include <linux/slab.h>
15#include <net/iucv/iucv.h>
16#include <asm/cpcmd.h>
17#include <asm/ebcdic.h>
18#include "smsgiucv.h"
19
20struct smsg_callback {
21	struct list_head list;
22	const char *prefix;
23	int len;
24	void (*callback)(const char *from, char *str);
25};
26
27MODULE_AUTHOR
28   ("(C) 2003 IBM Corporation by Martin Schwidefsky (schwidefsky@de.ibm.com)");
29MODULE_DESCRIPTION ("Linux for S/390 IUCV special message driver");
30
31static struct iucv_path *smsg_path;
32
33static DEFINE_SPINLOCK(smsg_list_lock);
34static LIST_HEAD(smsg_list);
35
36static int smsg_path_pending(struct iucv_path *, u8 *, u8 *);
37static void smsg_message_pending(struct iucv_path *, struct iucv_message *);
38
39static struct iucv_handler smsg_handler = {
40	.path_pending	 = smsg_path_pending,
41	.message_pending = smsg_message_pending,
42};
43
44static int smsg_path_pending(struct iucv_path *path, u8 *ipvmid, u8 *ipuser)
45{
46	if (strncmp(ipvmid, "*MSG    ", 8) != 0)
47		return -EINVAL;
48	/* Path pending from *MSG. */
49	return iucv_path_accept(path, &smsg_handler, "SMSGIUCV        ", NULL);
50}
51
52static void smsg_message_pending(struct iucv_path *path,
53				 struct iucv_message *msg)
54{
55	struct smsg_callback *cb;
56	unsigned char *buffer;
57	unsigned char sender[9];
58	int rc, i;
59
60	buffer = kmalloc(msg->length + 1, GFP_ATOMIC | GFP_DMA);
61	if (!buffer) {
62		iucv_message_reject(path, msg);
63		return;
64	}
65	rc = iucv_message_receive(path, msg, 0, buffer, msg->length, NULL);
66	if (rc == 0) {
67		buffer[msg->length] = 0;
68		EBCASC(buffer, msg->length);
69		memcpy(sender, buffer, 8);
70		sender[8] = 0;
71		/* Remove trailing whitespace from the sender name. */
72		for (i = 7; i >= 0; i--) {
73			if (sender[i] != ' ' && sender[i] != '\t')
74				break;
75			sender[i] = 0;
76		}
77		spin_lock(&smsg_list_lock);
78		list_for_each_entry(cb, &smsg_list, list)
79			if (strncmp(buffer + 8, cb->prefix, cb->len) == 0) {
80				cb->callback(sender, buffer + 8);
81				break;
82			}
83		spin_unlock(&smsg_list_lock);
84	}
85	kfree(buffer);
86}
87
88int smsg_register_callback(const char *prefix,
89			   void (*callback)(const char *from, char *str))
90{
91	struct smsg_callback *cb;
92
93	cb = kmalloc(sizeof(struct smsg_callback), GFP_KERNEL);
94	if (!cb)
95		return -ENOMEM;
96	cb->prefix = prefix;
97	cb->len = strlen(prefix);
98	cb->callback = callback;
99	spin_lock_bh(&smsg_list_lock);
100	list_add_tail(&cb->list, &smsg_list);
101	spin_unlock_bh(&smsg_list_lock);
102	return 0;
103}
104
105void smsg_unregister_callback(const char *prefix,
106			      void (*callback)(const char *from,
107					       char *str))
108{
109	struct smsg_callback *cb, *tmp;
110
111	spin_lock_bh(&smsg_list_lock);
112	cb = NULL;
113	list_for_each_entry(tmp, &smsg_list, list)
114		if (tmp->callback == callback &&
115		    strcmp(tmp->prefix, prefix) == 0) {
116			cb = tmp;
117			list_del(&cb->list);
118			break;
119		}
120	spin_unlock_bh(&smsg_list_lock);
121	kfree(cb);
122}
123
124static struct device_driver smsg_driver = {
125	.owner = THIS_MODULE,
126	.name = SMSGIUCV_DRV_NAME,
127	.bus  = &iucv_bus,
128};
129
130static void __exit smsg_exit(void)
131{
132	cpcmd("SET SMSG OFF", NULL, 0, NULL);
133	iucv_unregister(&smsg_handler, 1);
134	driver_unregister(&smsg_driver);
135}
136
137static int __init smsg_init(void)
138{
139	int rc;
140
141	if (!MACHINE_IS_VM) {
142		rc = -EPROTONOSUPPORT;
143		goto out;
144	}
145	rc = driver_register(&smsg_driver);
146	if (rc != 0)
147		goto out;
148	rc = iucv_register(&smsg_handler, 1);
149	if (rc)
150		goto out_driver;
151	smsg_path = iucv_path_alloc(255, 0, GFP_KERNEL);
152	if (!smsg_path) {
153		rc = -ENOMEM;
154		goto out_register;
155	}
156	rc = iucv_path_connect(smsg_path, &smsg_handler, "*MSG    ",
157			       NULL, NULL, NULL);
158	if (rc)
159		goto out_free_path;
160
161	cpcmd("SET SMSG IUCV", NULL, 0, NULL);
162	return 0;
163
164out_free_path:
165	iucv_path_free(smsg_path);
166	smsg_path = NULL;
167out_register:
168	iucv_unregister(&smsg_handler, 1);
169out_driver:
170	driver_unregister(&smsg_driver);
171out:
172	return rc;
173}
174
175module_init(smsg_init);
176module_exit(smsg_exit);
177MODULE_LICENSE("GPL");
178
179EXPORT_SYMBOL(smsg_register_callback);
180EXPORT_SYMBOL(smsg_unregister_callback);
181