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34#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
35
36#define DPRINTK(fmt, ...) \
37 pr_debug("(%s:%d) " fmt "\n", \
38 __func__, __LINE__, ##__VA_ARGS__)
39
40#include <linux/kernel.h>
41#include <linux/err.h>
42#include <linux/string.h>
43#include <linux/ctype.h>
44#include <linux/fcntl.h>
45#include <linux/mm.h>
46#include <linux/notifier.h>
47#include <linux/export.h>
48
49#include <asm/page.h>
50#include <asm/pgtable.h>
51#include <asm/xen/hypervisor.h>
52#include <asm/hypervisor.h>
53#include <xen/xenbus.h>
54#include <xen/features.h>
55
56#include "xenbus_comms.h"
57#include "xenbus_probe.h"
58
59
60static int backend_bus_id(char bus_id[XEN_BUS_ID_SIZE], const char *nodename)
61{
62 int domid, err;
63 const char *devid, *type, *frontend;
64 unsigned int typelen;
65
66 type = strchr(nodename, '/');
67 if (!type)
68 return -EINVAL;
69 type++;
70 typelen = strcspn(type, "/");
71 if (!typelen || type[typelen] != '/')
72 return -EINVAL;
73
74 devid = strrchr(nodename, '/') + 1;
75
76 err = xenbus_gather(XBT_NIL, nodename, "frontend-id", "%i", &domid,
77 "frontend", NULL, &frontend,
78 NULL);
79 if (err)
80 return err;
81 if (strlen(frontend) == 0)
82 err = -ERANGE;
83 if (!err && !xenbus_exists(XBT_NIL, frontend, ""))
84 err = -ENOENT;
85 kfree(frontend);
86
87 if (err)
88 return err;
89
90 if (snprintf(bus_id, XEN_BUS_ID_SIZE, "%.*s-%i-%s",
91 typelen, type, domid, devid) >= XEN_BUS_ID_SIZE)
92 return -ENOSPC;
93 return 0;
94}
95
96static int xenbus_uevent_backend(struct device *dev,
97 struct kobj_uevent_env *env)
98{
99 struct xenbus_device *xdev;
100 struct xenbus_driver *drv;
101 struct xen_bus_type *bus;
102
103 DPRINTK("");
104
105 if (dev == NULL)
106 return -ENODEV;
107
108 xdev = to_xenbus_device(dev);
109 bus = container_of(xdev->dev.bus, struct xen_bus_type, bus);
110
111 if (add_uevent_var(env, "MODALIAS=xen-backend:%s", xdev->devicetype))
112 return -ENOMEM;
113
114
115 if (add_uevent_var(env, "XENBUS_TYPE=%s", xdev->devicetype))
116 return -ENOMEM;
117
118 if (add_uevent_var(env, "XENBUS_PATH=%s", xdev->nodename))
119 return -ENOMEM;
120
121 if (add_uevent_var(env, "XENBUS_BASE_PATH=%s", bus->root))
122 return -ENOMEM;
123
124 if (dev->driver) {
125 drv = to_xenbus_driver(dev->driver);
126 if (drv && drv->uevent)
127 return drv->uevent(xdev, env);
128 }
129
130 return 0;
131}
132
133
134static int xenbus_probe_backend_unit(struct xen_bus_type *bus,
135 const char *dir,
136 const char *type,
137 const char *name)
138{
139 char *nodename;
140 int err;
141
142 nodename = kasprintf(GFP_KERNEL, "%s/%s", dir, name);
143 if (!nodename)
144 return -ENOMEM;
145
146 DPRINTK("%s\n", nodename);
147
148 err = xenbus_probe_node(bus, type, nodename);
149 kfree(nodename);
150 return err;
151}
152
153
154static int xenbus_probe_backend(struct xen_bus_type *bus, const char *type,
155 const char *domid)
156{
157 char *nodename;
158 int err = 0;
159 char **dir;
160 unsigned int i, dir_n = 0;
161
162 DPRINTK("");
163
164 nodename = kasprintf(GFP_KERNEL, "%s/%s/%s", bus->root, type, domid);
165 if (!nodename)
166 return -ENOMEM;
167
168 dir = xenbus_directory(XBT_NIL, nodename, "", &dir_n);
169 if (IS_ERR(dir)) {
170 kfree(nodename);
171 return PTR_ERR(dir);
172 }
173
174 for (i = 0; i < dir_n; i++) {
175 err = xenbus_probe_backend_unit(bus, nodename, type, dir[i]);
176 if (err)
177 break;
178 }
179 kfree(dir);
180 kfree(nodename);
181 return err;
182}
183
184static void frontend_changed(struct xenbus_watch *watch,
185 const char **vec, unsigned int len)
186{
187 xenbus_otherend_changed(watch, vec, len, 0);
188}
189
190static struct xen_bus_type xenbus_backend = {
191 .root = "backend",
192 .levels = 3,
193 .get_bus_id = backend_bus_id,
194 .probe = xenbus_probe_backend,
195 .otherend_changed = frontend_changed,
196 .bus = {
197 .name = "xen-backend",
198 .match = xenbus_match,
199 .uevent = xenbus_uevent_backend,
200 .probe = xenbus_dev_probe,
201 .remove = xenbus_dev_remove,
202 .shutdown = xenbus_dev_shutdown,
203 .dev_groups = xenbus_dev_groups,
204 },
205};
206
207static void backend_changed(struct xenbus_watch *watch,
208 const char **vec, unsigned int len)
209{
210 DPRINTK("");
211
212 xenbus_dev_changed(vec[XS_WATCH_PATH], &xenbus_backend);
213}
214
215static struct xenbus_watch be_watch = {
216 .node = "backend",
217 .callback = backend_changed,
218};
219
220static int read_frontend_details(struct xenbus_device *xendev)
221{
222 return xenbus_read_otherend_details(xendev, "frontend-id", "frontend");
223}
224
225int xenbus_dev_is_online(struct xenbus_device *dev)
226{
227 int rc, val;
228
229 rc = xenbus_scanf(XBT_NIL, dev->nodename, "online", "%d", &val);
230 if (rc != 1)
231 val = 0;
232
233 return val;
234}
235EXPORT_SYMBOL_GPL(xenbus_dev_is_online);
236
237int __xenbus_register_backend(struct xenbus_driver *drv, struct module *owner,
238 const char *mod_name)
239{
240 drv->read_otherend_details = read_frontend_details;
241
242 return xenbus_register_driver_common(drv, &xenbus_backend,
243 owner, mod_name);
244}
245EXPORT_SYMBOL_GPL(__xenbus_register_backend);
246
247static int backend_probe_and_watch(struct notifier_block *notifier,
248 unsigned long event,
249 void *data)
250{
251
252 xenbus_probe_devices(&xenbus_backend);
253 register_xenbus_watch(&be_watch);
254
255 return NOTIFY_DONE;
256}
257
258static int __init xenbus_probe_backend_init(void)
259{
260 static struct notifier_block xenstore_notifier = {
261 .notifier_call = backend_probe_and_watch
262 };
263 int err;
264
265 DPRINTK("");
266
267
268 err = bus_register(&xenbus_backend.bus);
269 if (err)
270 return err;
271
272 register_xenstore_notifier(&xenstore_notifier);
273
274 return 0;
275}
276subsys_initcall(xenbus_probe_backend_init);
277
