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[elogind.git] / device.c
1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
2
3 /***
4   This file is part of systemd.
5
6   Copyright 2010 Lennart Poettering
7
8   systemd is free software; you can redistribute it and/or modify it
9   under the terms of the GNU General Public License as published by
10   the Free Software Foundation; either version 2 of the License, or
11   (at your option) any later version.
12
13   systemd is distributed in the hope that it will be useful, but
14   WITHOUT ANY WARRANTY; without even the implied warranty of
15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16   General Public License for more details.
17
18   You should have received a copy of the GNU General Public License
19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
20 ***/
21
22 #include <errno.h>
23 #include <sys/epoll.h>
24 #include <libudev.h>
25
26 #include "unit.h"
27 #include "device.h"
28 #include "strv.h"
29 #include "log.h"
30
31 static const UnitActiveState state_translation_table[_DEVICE_STATE_MAX] = {
32         [DEVICE_DEAD] = UNIT_INACTIVE,
33         [DEVICE_AVAILABLE] = UNIT_ACTIVE
34 };
35
36 static const char* const state_string_table[_DEVICE_STATE_MAX] = {
37         [DEVICE_DEAD] = "dead",
38         [DEVICE_AVAILABLE] = "available"
39 };
40
41 static void device_done(Unit *u) {
42         Device *d = DEVICE(u);
43
44         assert(d);
45         free(d->sysfs);
46 }
47
48 static void device_set_state(Device *d, DeviceState state) {
49         DeviceState old_state;
50         assert(d);
51
52         if (state == d->state)
53                 return;
54
55         old_state = d->state;
56         d->state = state;
57
58         log_debug("%s changed %s → %s", unit_id(UNIT(d)), state_string_table[old_state], state_string_table[state]);
59
60         unit_notify(UNIT(d), state_translation_table[old_state], state_translation_table[state]);
61 }
62
63 static int device_coldplug(Unit *u) {
64         Device *d = DEVICE(u);
65
66         assert(d);
67         assert(d->state == DEVICE_DEAD);
68
69         if (d->sysfs)
70                 device_set_state(d, DEVICE_AVAILABLE);
71
72         return 0;
73 }
74
75 static void device_dump(Unit *u, FILE *f, const char *prefix) {
76         Device *d = DEVICE(u);
77
78         assert(d);
79
80         fprintf(f,
81                 "%sDevice State: %s\n"
82                 "%sSysfs Path: %s\n",
83                 prefix, state_string_table[d->state],
84                 prefix, strna(d->sysfs));
85 }
86
87 static UnitActiveState device_active_state(Unit *u) {
88         assert(u);
89
90         return state_translation_table[DEVICE(u)->state];
91 }
92
93 static int device_add_escaped_name(Unit *u, const char *dn, bool make_id) {
94         char *e;
95         int r;
96
97         assert(u);
98         assert(dn);
99         assert(dn[0] == '/');
100
101         if (!(e = unit_name_escape_path(dn+1, ".device")))
102                 return -ENOMEM;
103
104         r = unit_add_name(u, e);
105
106         if (r >= 0 && make_id)
107                 unit_choose_id(u, e);
108
109         free(e);
110
111         if (r < 0 && r != -EEXIST)
112                 return r;
113
114         return 0;
115 }
116
117 static int device_process_new_device(Manager *m, struct udev_device *dev, bool update_state) {
118         const char *dn, *names, *wants, *sysfs, *expose;
119         Unit *u = NULL;
120         int r;
121         char *e, *w, *state;
122         size_t l;
123         bool delete;
124         struct udev_list_entry *item = NULL, *first = NULL;
125
126         assert(m);
127
128         if (!(sysfs = udev_device_get_syspath(dev)))
129                 return -ENOMEM;
130
131         /* Check whether this entry is even relevant for us. */
132         dn = udev_device_get_devnode(dev);
133         expose = udev_device_get_property_value(dev, "SYSTEMD_EXPOSE");
134         names = udev_device_get_property_value(dev, "SYSTEMD_NAMES");
135         wants = udev_device_get_property_value(dev, "SYSTEMD_WANTS");
136
137         if (expose) {
138                 int b;
139
140                 if ((b = parse_boolean(expose)) < 0) {
141                         log_error("Failed to parse SYSTEMD_EXPOSE udev property for device %s: %s", sysfs, expose);
142                         return 0;
143                 }
144
145                 if (!b)
146                         return 0;
147         } else
148                 if (!dn && !names && !wants)
149                         return 0;
150
151         /* Ok, seems kinda interesting. Now, let's see if this one
152          * already exists. */
153
154         assert(sysfs[0] == '/');
155         if (!(e = unit_name_escape_path(sysfs+1, ".device")))
156                 return -ENOMEM;
157
158         if (!(u = manager_get_unit(m, e))) {
159                 const char *model;
160
161                 delete = true;
162
163                 if (!(u = unit_new(m))) {
164                         free(e);
165                         return -ENOMEM;
166                 }
167
168                 r = unit_add_name(u, e);
169                 free(e);
170
171                 if (r < 0)
172                         goto fail;
173
174                 if (!(DEVICE(u)->sysfs = strdup(sysfs))) {
175                         r = -ENOMEM;
176                         goto fail;
177                 }
178
179                 if ((model = udev_device_get_property_value(dev, "ID_MODEL_FROM_DATABASE")) ||
180                     (model = udev_device_get_property_value(dev, "ID_MODEL"))) {
181                         if ((r = unit_set_description(u, model)) < 0)
182                                 goto fail;
183                 } else if (dn)
184                         if ((r = unit_set_description(u, dn)) < 0)
185                                 goto fail;
186
187                 unit_add_to_load_queue(u);
188         } else {
189                 delete = false;
190                 free(e);
191         }
192
193         if (dn)
194                 if ((r = device_add_escaped_name(u, dn, true)) < 0)
195                         goto fail;
196
197         first = udev_device_get_devlinks_list_entry(dev);
198         udev_list_entry_foreach(item, first)
199                 if ((r = device_add_escaped_name(u, udev_list_entry_get_name(item), false)) < 0)
200                         goto fail;
201
202         if (names) {
203                 FOREACH_WORD(w, l, names, state) {
204                         if (!(e = strndup(w, l))) {
205                                 r = -ENOMEM;
206                                 goto fail;
207                         }
208
209                         r = unit_add_name(u, e);
210                         free(e);
211
212                         if (r < 0 && r != -EEXIST)
213                                 goto fail;
214                 }
215         }
216
217         if (wants) {
218                 FOREACH_WORD(w, l, wants, state) {
219                         if (!(e = strndup(w, l))) {
220                                 r = -ENOMEM;
221                                 goto fail;
222                         }
223
224                         r = unit_add_dependency_by_name(u, UNIT_WANTS, e);
225                         free(e);
226
227                         if (r < 0)
228                                 goto fail;
229                 }
230         }
231
232         if (update_state) {
233                 manager_dispatch_load_queue(u->meta.manager);
234                 device_set_state(DEVICE(u), DEVICE_AVAILABLE);
235         }
236
237         unit_add_to_dbus_queue(u);
238
239         return 0;
240
241 fail:
242         if (delete && u)
243                 unit_free(u);
244         return r;
245 }
246
247 static int device_process_path(Manager *m, const char *path, bool update_state) {
248         int r;
249         struct udev_device *dev;
250
251         assert(m);
252         assert(path);
253
254         if (!(dev = udev_device_new_from_syspath(m->udev, path))) {
255                 log_warning("Failed to get udev device object from udev for path %s.", path);
256                 return -ENOMEM;
257         }
258
259         r = device_process_new_device(m, dev, update_state);
260         udev_device_unref(dev);
261         return r;
262 }
263
264 static int device_process_removed_device(Manager *m, struct udev_device *dev) {
265         const char *sysfs;
266         char *e;
267         Unit *u;
268         Device *d;
269
270         assert(m);
271         assert(dev);
272
273         if (!(sysfs = udev_device_get_syspath(dev)))
274                 return -ENOMEM;
275
276         assert(sysfs[0] == '/');
277         if (!(e = unit_name_escape_path(sysfs+1, ".device")))
278                 return -ENOMEM;
279
280         u = manager_get_unit(m, e);
281         free(e);
282
283         if (!u)
284                 return 0;
285
286         d = DEVICE(u);
287         free(d->sysfs);
288         d->sysfs = NULL;
289
290         device_set_state(d, DEVICE_DEAD);
291         return 0;
292 }
293
294 static void device_shutdown(Manager *m) {
295         assert(m);
296
297         if (m->udev_monitor)
298                 udev_monitor_unref(m->udev_monitor);
299
300         if (m->udev)
301                 udev_unref(m->udev);
302 }
303
304 static int device_enumerate(Manager *m) {
305         struct epoll_event ev;
306         int r;
307         struct udev_enumerate *e = NULL;
308         struct udev_list_entry *item = NULL, *first = NULL;
309
310         assert(m);
311
312         if (!(m->udev = udev_new()))
313                 return -ENOMEM;
314
315         if (!(m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev"))) {
316                 r = -ENOMEM;
317                 goto fail;
318         }
319
320         if (udev_monitor_enable_receiving(m->udev_monitor) < 0) {
321                 r = -EIO;
322                 goto fail;
323         }
324
325         m->udev_watch.type = WATCH_UDEV;
326         m->udev_watch.fd = udev_monitor_get_fd(m->udev_monitor);
327
328         zero(ev);
329         ev.events = EPOLLIN;
330         ev.data.ptr = &m->udev_watch;
331
332         if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->udev_watch.fd, &ev) < 0)
333                 return -errno;
334
335         if (!(e = udev_enumerate_new(m->udev))) {
336                 r = -ENOMEM;
337                 goto fail;
338         }
339
340         if (udev_enumerate_scan_devices(e) < 0) {
341                 r = -EIO;
342                 goto fail;
343         }
344
345         first = udev_enumerate_get_list_entry(e);
346         udev_list_entry_foreach(item, first)
347                 device_process_path(m, udev_list_entry_get_name(item), false);
348
349         udev_enumerate_unref(e);
350         return 0;
351
352 fail:
353         if (e)
354                 udev_enumerate_unref(e);
355
356         device_shutdown(m);
357         return r;
358 }
359
360 void device_fd_event(Manager *m, int events) {
361         struct udev_device *dev;
362         int r;
363         const char *action;
364
365         assert(m);
366         assert(events == EPOLLIN);
367
368         if (!(dev = udev_monitor_receive_device(m->udev_monitor))) {
369                 log_error("Failed to receive device.");
370                 return;
371         }
372
373         if (!(action = udev_device_get_action(dev))) {
374                 log_error("Failed to get udev action string.");
375                 goto fail;
376         }
377
378         if (streq(action, "remove")) {
379                 if ((r = device_process_removed_device(m, dev)) < 0) {
380                         log_error("Failed to process udev device event: %s", strerror(-r));
381                         goto fail;
382                 }
383         } else {
384                 if ((r = device_process_new_device(m, dev, true)) < 0) {
385                         log_error("Failed to process udev device event: %s", strerror(-r));
386                         goto fail;
387                 }
388         }
389
390 fail:
391         udev_device_unref(dev);
392 }
393
394 const UnitVTable device_vtable = {
395         .suffix = ".device",
396
397         .init = unit_load_fragment_and_dropin_optional,
398         .done = device_done,
399         .coldplug = device_coldplug,
400
401         .dump = device_dump,
402
403         .active_state = device_active_state,
404
405         .enumerate = device_enumerate,
406         .shutdown = device_shutdown
407 };