1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * net/9p/9p.c
4 *
5 * 9P entry point
6 *
7 * Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
8 * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
9 * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
10 */
11
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14 #include <linux/module.h>
15 #include <linux/errno.h>
16 #include <linux/sched.h>
17 #include <linux/moduleparam.h>
18 #include <net/9p/9p.h>
19 #include <linux/fs.h>
20 #include <linux/parser.h>
21 #include <net/9p/client.h>
22 #include <net/9p/transport.h>
23 #include <linux/list.h>
24 #include <linux/spinlock.h>
25
26 #ifdef CONFIG_NET_9P_DEBUG
27 unsigned int p9_debug_level; /* feature-rific global debug level */
28 EXPORT_SYMBOL(p9_debug_level);
29 module_param_named(debug, p9_debug_level, uint, 0);
30 MODULE_PARM_DESC(debug, "9P debugging level");
31
_p9_debug(enum p9_debug_flags level,const char * func,const char * fmt,...)32 void _p9_debug(enum p9_debug_flags level, const char *func,
33 const char *fmt, ...)
34 {
35 struct va_format vaf;
36 va_list args;
37
38 if ((p9_debug_level & level) != level)
39 return;
40
41 va_start(args, fmt);
42
43 vaf.fmt = fmt;
44 vaf.va = &args;
45
46 if (level == P9_DEBUG_9P)
47 pr_notice("(%8.8d) %pV", task_pid_nr(current), &vaf);
48 else
49 pr_notice("-- %s (%d): %pV", func, task_pid_nr(current), &vaf);
50
51 va_end(args);
52 }
53 EXPORT_SYMBOL(_p9_debug);
54 #endif
55
56 /* Dynamic Transport Registration Routines */
57
58 static DEFINE_SPINLOCK(v9fs_trans_lock);
59 static LIST_HEAD(v9fs_trans_list);
60
61 /**
62 * v9fs_register_trans - register a new transport with 9p
63 * @m: structure describing the transport module and entry points
64 *
65 */
v9fs_register_trans(struct p9_trans_module * m)66 void v9fs_register_trans(struct p9_trans_module *m)
67 {
68 spin_lock(&v9fs_trans_lock);
69 list_add_tail(&m->list, &v9fs_trans_list);
70 spin_unlock(&v9fs_trans_lock);
71 }
72 EXPORT_SYMBOL(v9fs_register_trans);
73
74 /**
75 * v9fs_unregister_trans - unregister a 9p transport
76 * @m: the transport to remove
77 *
78 */
v9fs_unregister_trans(struct p9_trans_module * m)79 void v9fs_unregister_trans(struct p9_trans_module *m)
80 {
81 spin_lock(&v9fs_trans_lock);
82 list_del_init(&m->list);
83 spin_unlock(&v9fs_trans_lock);
84 }
85 EXPORT_SYMBOL(v9fs_unregister_trans);
86
87 /**
88 * v9fs_get_trans_by_name - get transport with the matching name
89 * @s: string identifying transport
90 *
91 */
v9fs_get_trans_by_name(char * s)92 struct p9_trans_module *v9fs_get_trans_by_name(char *s)
93 {
94 struct p9_trans_module *t, *found = NULL;
95
96 spin_lock(&v9fs_trans_lock);
97
98 list_for_each_entry(t, &v9fs_trans_list, list)
99 if (strcmp(t->name, s) == 0 &&
100 try_module_get(t->owner)) {
101 found = t;
102 break;
103 }
104
105 spin_unlock(&v9fs_trans_lock);
106 return found;
107 }
108 EXPORT_SYMBOL(v9fs_get_trans_by_name);
109
110 /**
111 * v9fs_get_default_trans - get the default transport
112 *
113 */
114
v9fs_get_default_trans(void)115 struct p9_trans_module *v9fs_get_default_trans(void)
116 {
117 struct p9_trans_module *t, *found = NULL;
118
119 spin_lock(&v9fs_trans_lock);
120
121 list_for_each_entry(t, &v9fs_trans_list, list)
122 if (t->def && try_module_get(t->owner)) {
123 found = t;
124 break;
125 }
126
127 if (!found)
128 list_for_each_entry(t, &v9fs_trans_list, list)
129 if (try_module_get(t->owner)) {
130 found = t;
131 break;
132 }
133
134 spin_unlock(&v9fs_trans_lock);
135 return found;
136 }
137 EXPORT_SYMBOL(v9fs_get_default_trans);
138
139 /**
140 * v9fs_put_trans - put trans
141 * @m: transport to put
142 *
143 */
v9fs_put_trans(struct p9_trans_module * m)144 void v9fs_put_trans(struct p9_trans_module *m)
145 {
146 if (m)
147 module_put(m->owner);
148 }
149
150 /**
151 * init_p9 - Initialize module
152 *
153 */
init_p9(void)154 static int __init init_p9(void)
155 {
156 int ret;
157
158 ret = p9_client_init();
159 if (ret)
160 return ret;
161
162 p9_error_init();
163 pr_info("Installing 9P2000 support\n");
164 p9_trans_fd_init();
165
166 return ret;
167 }
168
169 /**
170 * exit_p9 - shutdown module
171 *
172 */
173
exit_p9(void)174 static void __exit exit_p9(void)
175 {
176 pr_info("Unloading 9P2000 support\n");
177
178 p9_trans_fd_exit();
179 p9_client_exit();
180 }
181
182 module_init(init_p9)
183 module_exit(exit_p9)
184
185 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
186 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
187 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
188 MODULE_LICENSE("GPL");
189 MODULE_IMPORT_NS(VFS_internal_I_am_really_a_filesystem_and_am_NOT_a_driver);
190 MODULE_DESCRIPTION("Plan 9 Resource Sharing Support (9P2000)");
191