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