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
20 struct smsg_callback {
21 struct list_head list;
22 const char *prefix;
23 int len;
24 void (*callback)(const char *from, char *str);
25 };
26
27 MODULE_AUTHOR
28 ("(C) 2003 IBM Corporation by Martin Schwidefsky (schwidefsky@de.ibm.com)");
29 MODULE_DESCRIPTION ("Linux for S/390 IUCV special message driver");
30
31 static struct iucv_path *smsg_path;
32
33 static DEFINE_SPINLOCK(smsg_list_lock);
34 static LIST_HEAD(smsg_list);
35
36 static int smsg_path_pending(struct iucv_path *, u8 *, u8 *);
37 static void smsg_message_pending(struct iucv_path *, struct iucv_message *);
38
39 static struct iucv_handler smsg_handler = {
40 .path_pending = smsg_path_pending,
41 .message_pending = smsg_message_pending,
42 };
43
smsg_path_pending(struct iucv_path * path,u8 * ipvmid,u8 * ipuser)44 static 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
smsg_message_pending(struct iucv_path * path,struct iucv_message * msg)52 static 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
smsg_register_callback(const char * prefix,void (* callback)(const char * from,char * str))88 int 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
smsg_unregister_callback(const char * prefix,void (* callback)(const char * from,char * str))105 void 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
124 static struct device_driver smsg_driver = {
125 .owner = THIS_MODULE,
126 .name = SMSGIUCV_DRV_NAME,
127 .bus = &iucv_bus,
128 };
129
smsg_exit(void)130 static 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
smsg_init(void)137 static 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
164 out_free_path:
165 iucv_path_free(smsg_path);
166 smsg_path = NULL;
167 out_register:
168 iucv_unregister(&smsg_handler, 1);
169 out_driver:
170 driver_unregister(&smsg_driver);
171 out:
172 return rc;
173 }
174
175 module_init(smsg_init);
176 module_exit(smsg_exit);
177 MODULE_LICENSE("GPL");
178
179 EXPORT_SYMBOL(smsg_register_callback);
180 EXPORT_SYMBOL(smsg_unregister_callback);
181