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1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2013 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 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 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
14228c0d MB |
22 | #include "util.h" |
23 | #include "mkdir.h" | |
24 | #include "fileio.h" | |
60f067b4 JS |
25 | #include "libudev.h" |
26 | #include "udev-util.h" | |
27 | #include "def.h" | |
28 | ||
29 | static struct udev_device *find_pci_or_platform_parent(struct udev_device *device) { | |
30 | struct udev_device *parent; | |
31 | const char *subsystem, *sysname; | |
32 | ||
33 | assert(device); | |
34 | ||
35 | parent = udev_device_get_parent(device); | |
36 | if (!parent) | |
37 | return NULL; | |
38 | ||
39 | subsystem = udev_device_get_subsystem(parent); | |
40 | if (!subsystem) | |
41 | return NULL; | |
42 | ||
43 | sysname = udev_device_get_sysname(parent); | |
44 | if (!sysname) | |
45 | return NULL; | |
46 | ||
47 | if (streq(subsystem, "drm")) { | |
48 | const char *c; | |
49 | ||
50 | c = startswith(sysname, "card"); | |
51 | if (!c) | |
52 | return NULL; | |
53 | ||
54 | c += strspn(c, DIGITS); | |
55 | if (*c == '-') { | |
56 | /* A connector DRM device, let's ignore all but LVDS and eDP! */ | |
57 | ||
58 | if (!startswith(c, "-LVDS-") && | |
59 | !startswith(c, "-Embedded DisplayPort-")) | |
60 | return NULL; | |
61 | } | |
62 | ||
63 | } else if (streq(subsystem, "pci")) { | |
64 | const char *value; | |
65 | ||
66 | value = udev_device_get_sysattr_value(parent, "class"); | |
67 | if (value) { | |
68 | unsigned long class = 0; | |
69 | ||
70 | if (safe_atolu(value, &class) < 0) { | |
71 | log_warning("Cannot parse PCI class %s of device %s:%s.", | |
72 | value, subsystem, sysname); | |
73 | return NULL; | |
74 | } | |
75 | ||
76 | /* Graphics card */ | |
77 | if (class == 0x30000) | |
78 | return parent; | |
79 | } | |
80 | ||
81 | } else if (streq(subsystem, "platform")) | |
82 | return parent; | |
83 | ||
84 | return find_pci_or_platform_parent(parent); | |
85 | } | |
86 | ||
87 | static bool same_device(struct udev_device *a, struct udev_device *b) { | |
88 | assert(a); | |
89 | assert(b); | |
90 | ||
91 | if (!streq_ptr(udev_device_get_subsystem(a), udev_device_get_subsystem(b))) | |
92 | return false; | |
93 | ||
94 | if (!streq_ptr(udev_device_get_sysname(a), udev_device_get_sysname(b))) | |
95 | return false; | |
96 | ||
97 | return true; | |
98 | } | |
99 | ||
100 | static bool validate_device(struct udev *udev, struct udev_device *device) { | |
101 | _cleanup_udev_enumerate_unref_ struct udev_enumerate *enumerate = NULL; | |
102 | struct udev_list_entry *item = NULL, *first = NULL; | |
103 | struct udev_device *parent; | |
104 | const char *v, *subsystem; | |
105 | int r; | |
106 | ||
107 | assert(udev); | |
108 | assert(device); | |
109 | ||
110 | /* Verify whether we should actually care for a specific | |
111 | * backlight device. For backlight devices there might be | |
112 | * multiple ways to access the same control: "firmware" | |
113 | * (i.e. ACPI), "platform" (i.e. via the machine's EC) and | |
114 | * "raw" (via the graphics card). In general we should prefer | |
115 | * "firmware" (i.e. ACPI) or "platform" access over "raw" | |
116 | * access, in order not to confuse the BIOS/EC, and | |
117 | * compatibility with possible low-level hotkey handling of | |
118 | * screen brightness. The kernel will already make sure to | |
119 | * expose only one of "firmware" and "platform" for the same | |
120 | * device to userspace. However, we still need to make sure | |
121 | * that we use "raw" only if no "firmware" or "platform" | |
122 | * device for the same device exists. */ | |
123 | ||
124 | subsystem = udev_device_get_subsystem(device); | |
125 | if (!streq_ptr(subsystem, "backlight")) | |
126 | return true; | |
127 | ||
128 | v = udev_device_get_sysattr_value(device, "type"); | |
129 | if (!streq_ptr(v, "raw")) | |
130 | return true; | |
131 | ||
132 | parent = find_pci_or_platform_parent(device); | |
133 | if (!parent) | |
134 | return true; | |
135 | ||
136 | subsystem = udev_device_get_subsystem(parent); | |
137 | if (!subsystem) | |
138 | return true; | |
139 | ||
140 | enumerate = udev_enumerate_new(udev); | |
141 | if (!enumerate) | |
142 | return true; | |
143 | ||
144 | r = udev_enumerate_add_match_subsystem(enumerate, "backlight"); | |
145 | if (r < 0) | |
146 | return true; | |
147 | ||
148 | r = udev_enumerate_scan_devices(enumerate); | |
149 | if (r < 0) | |
150 | return true; | |
151 | ||
152 | first = udev_enumerate_get_list_entry(enumerate); | |
153 | udev_list_entry_foreach(item, first) { | |
154 | _cleanup_udev_device_unref_ struct udev_device *other; | |
155 | struct udev_device *other_parent; | |
156 | const char *other_subsystem; | |
157 | ||
158 | other = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item)); | |
159 | if (!other) | |
160 | return true; | |
161 | ||
162 | if (same_device(device, other)) | |
163 | continue; | |
164 | ||
165 | v = udev_device_get_sysattr_value(other, "type"); | |
166 | if (!streq_ptr(v, "platform") && !streq_ptr(v, "firmware")) | |
167 | continue; | |
168 | ||
169 | /* OK, so there's another backlight device, and it's a | |
170 | * platform or firmware device, so, let's see if we | |
171 | * can verify it belongs to the same device as | |
172 | * ours. */ | |
173 | other_parent = find_pci_or_platform_parent(other); | |
174 | if (!other_parent) | |
175 | continue; | |
176 | ||
177 | if (same_device(parent, other_parent)) { | |
178 | /* Both have the same PCI parent, that means | |
179 | * we are out. */ | |
180 | log_debug("Skipping backlight device %s, since device %s is on same PCI device and takes precedence.", | |
181 | udev_device_get_sysname(device), | |
182 | udev_device_get_sysname(other)); | |
183 | return false; | |
184 | } | |
185 | ||
186 | other_subsystem = udev_device_get_subsystem(other_parent); | |
187 | if (streq_ptr(other_subsystem, "platform") && streq_ptr(subsystem, "pci")) { | |
188 | /* The other is connected to the platform bus | |
189 | * and we are a PCI device, that also means we | |
190 | * are out. */ | |
191 | log_debug("Skipping backlight device %s, since device %s is a platform device and takes precedence.", | |
192 | udev_device_get_sysname(device), | |
193 | udev_device_get_sysname(other)); | |
194 | return false; | |
195 | } | |
196 | } | |
197 | ||
198 | return true; | |
199 | } | |
200 | ||
201 | static unsigned get_max_brightness(struct udev_device *device) { | |
202 | int r; | |
203 | const char *max_brightness_str; | |
204 | unsigned max_brightness; | |
205 | ||
206 | max_brightness_str = udev_device_get_sysattr_value(device, "max_brightness"); | |
207 | if (!max_brightness_str) { | |
208 | log_warning("Failed to read 'max_brightness' attribute."); | |
209 | return 0; | |
210 | } | |
211 | ||
212 | r = safe_atou(max_brightness_str, &max_brightness); | |
213 | if (r < 0) { | |
f47781d8 | 214 | log_warning_errno(r, "Failed to parse 'max_brightness' \"%s\": %m", max_brightness_str); |
60f067b4 JS |
215 | return 0; |
216 | } | |
217 | ||
218 | if (max_brightness <= 0) { | |
219 | log_warning("Maximum brightness is 0, ignoring device."); | |
220 | return 0; | |
221 | } | |
222 | ||
223 | return max_brightness; | |
224 | } | |
225 | ||
226 | /* Some systems turn the backlight all the way off at the lowest levels. | |
227 | * clamp_brightness clamps the saved brightness to at least 1 or 5% of | |
228 | * max_brightness in case of 'backlight' subsystem. This avoids preserving | |
229 | * an unreadably dim screen, which would otherwise force the user to | |
230 | * disable state restoration. */ | |
231 | static void clamp_brightness(struct udev_device *device, char **value, unsigned max_brightness) { | |
232 | int r; | |
233 | unsigned brightness, new_brightness, min_brightness; | |
234 | const char *subsystem; | |
235 | ||
236 | r = safe_atou(*value, &brightness); | |
237 | if (r < 0) { | |
f47781d8 | 238 | log_warning_errno(r, "Failed to parse brightness \"%s\": %m", *value); |
60f067b4 JS |
239 | return; |
240 | } | |
241 | ||
242 | subsystem = udev_device_get_subsystem(device); | |
243 | if (streq_ptr(subsystem, "backlight")) | |
244 | min_brightness = MAX(1U, max_brightness/20); | |
245 | else | |
246 | min_brightness = 0; | |
247 | ||
248 | new_brightness = CLAMP(brightness, min_brightness, max_brightness); | |
249 | if (new_brightness != brightness) { | |
250 | char *old_value = *value; | |
251 | ||
252 | r = asprintf(value, "%u", new_brightness); | |
253 | if (r < 0) { | |
254 | log_oom(); | |
255 | return; | |
256 | } | |
257 | ||
258 | log_info("Saved brightness %s %s to %s.", old_value, | |
259 | new_brightness > brightness ? | |
260 | "too low; increasing" : "too high; decreasing", | |
261 | *value); | |
262 | ||
263 | free(old_value); | |
264 | } | |
265 | } | |
14228c0d MB |
266 | |
267 | int main(int argc, char *argv[]) { | |
60f067b4 JS |
268 | _cleanup_udev_unref_ struct udev *udev = NULL; |
269 | _cleanup_udev_device_unref_ struct udev_device *device = NULL; | |
270 | _cleanup_free_ char *saved = NULL, *ss = NULL, *escaped_ss = NULL, *escaped_sysname = NULL, *escaped_path_id = NULL; | |
271 | const char *sysname, *path_id; | |
272 | unsigned max_brightness; | |
14228c0d MB |
273 | int r; |
274 | ||
275 | if (argc != 3) { | |
276 | log_error("This program requires two arguments."); | |
277 | return EXIT_FAILURE; | |
278 | } | |
279 | ||
280 | log_set_target(LOG_TARGET_AUTO); | |
281 | log_parse_environment(); | |
282 | log_open(); | |
283 | ||
284 | umask(0022); | |
285 | ||
286 | r = mkdir_p("/var/lib/systemd/backlight", 0755); | |
287 | if (r < 0) { | |
f47781d8 | 288 | log_error_errno(r, "Failed to create backlight directory /var/lib/systemd/backlight: %m"); |
60f067b4 | 289 | return EXIT_FAILURE; |
14228c0d MB |
290 | } |
291 | ||
292 | udev = udev_new(); | |
293 | if (!udev) { | |
60f067b4 JS |
294 | log_oom(); |
295 | return EXIT_FAILURE; | |
296 | } | |
297 | ||
298 | sysname = strchr(argv[2], ':'); | |
299 | if (!sysname) { | |
300 | log_error("Requires a subsystem and sysname pair specifying a backlight device."); | |
301 | return EXIT_FAILURE; | |
302 | } | |
303 | ||
304 | ss = strndup(argv[2], sysname - argv[2]); | |
305 | if (!ss) { | |
306 | log_oom(); | |
307 | return EXIT_FAILURE; | |
308 | } | |
309 | ||
310 | sysname++; | |
311 | ||
312 | if (!streq(ss, "backlight") && !streq(ss, "leds")) { | |
313 | log_error("Not a backlight or LED device: '%s:%s'", ss, sysname); | |
314 | return EXIT_FAILURE; | |
14228c0d MB |
315 | } |
316 | ||
317 | errno = 0; | |
60f067b4 | 318 | device = udev_device_new_from_subsystem_sysname(udev, ss, sysname); |
14228c0d | 319 | if (!device) { |
60f067b4 | 320 | if (errno != 0) |
f47781d8 | 321 | log_error_errno(errno, "Failed to get backlight or LED device '%s:%s': %m", ss, sysname); |
60f067b4 JS |
322 | else |
323 | log_oom(); | |
14228c0d | 324 | |
60f067b4 | 325 | return EXIT_FAILURE; |
14228c0d MB |
326 | } |
327 | ||
60f067b4 JS |
328 | /* If max_brightness is 0, then there is no actual backlight |
329 | * device. This happens on desktops with Asus mainboards | |
330 | * that load the eeepc-wmi module. | |
331 | */ | |
332 | max_brightness = get_max_brightness(device); | |
333 | if (max_brightness == 0) | |
334 | return EXIT_SUCCESS; | |
335 | ||
336 | escaped_ss = cescape(ss); | |
337 | if (!escaped_ss) { | |
338 | log_oom(); | |
339 | return EXIT_FAILURE; | |
340 | } | |
341 | ||
342 | escaped_sysname = cescape(sysname); | |
343 | if (!escaped_sysname) { | |
344 | log_oom(); | |
345 | return EXIT_FAILURE; | |
14228c0d MB |
346 | } |
347 | ||
60f067b4 JS |
348 | path_id = udev_device_get_property_value(device, "ID_PATH"); |
349 | if (path_id) { | |
350 | escaped_path_id = cescape(path_id); | |
351 | if (!escaped_path_id) { | |
352 | log_oom(); | |
353 | return EXIT_FAILURE; | |
354 | } | |
355 | ||
356 | saved = strjoin("/var/lib/systemd/backlight/", escaped_path_id, ":", escaped_ss, ":", escaped_sysname, NULL); | |
357 | } else | |
358 | saved = strjoin("/var/lib/systemd/backlight/", escaped_ss, ":", escaped_sysname, NULL); | |
359 | ||
14228c0d | 360 | if (!saved) { |
60f067b4 JS |
361 | log_oom(); |
362 | return EXIT_FAILURE; | |
14228c0d MB |
363 | } |
364 | ||
60f067b4 JS |
365 | /* If there are multiple conflicting backlight devices, then |
366 | * their probing at boot-time might happen in any order. This | |
367 | * means the validity checking of the device then is not | |
368 | * reliable, since it might not see other devices conflicting | |
369 | * with a specific backlight. To deal with this, we will | |
370 | * actively delete backlight state files at shutdown (where | |
371 | * device probing should be complete), so that the validity | |
372 | * check at boot time doesn't have to be reliable. */ | |
373 | ||
5eef597e | 374 | if (streq(argv[1], "load")) { |
14228c0d MB |
375 | _cleanup_free_ char *value = NULL; |
376 | ||
5eef597e MP |
377 | if (!shall_restore_state()) |
378 | return EXIT_SUCCESS; | |
379 | ||
60f067b4 JS |
380 | if (!validate_device(udev, device)) |
381 | return EXIT_SUCCESS; | |
382 | ||
14228c0d MB |
383 | r = read_one_line_file(saved, &value); |
384 | if (r < 0) { | |
385 | ||
60f067b4 JS |
386 | if (r == -ENOENT) |
387 | return EXIT_SUCCESS; | |
14228c0d | 388 | |
f47781d8 | 389 | log_error_errno(r, "Failed to read %s: %m", saved); |
60f067b4 | 390 | return EXIT_FAILURE; |
14228c0d MB |
391 | } |
392 | ||
60f067b4 JS |
393 | clamp_brightness(device, &value, max_brightness); |
394 | ||
14228c0d MB |
395 | r = udev_device_set_sysattr_value(device, "brightness", value); |
396 | if (r < 0) { | |
f47781d8 | 397 | log_error_errno(r, "Failed to write system 'brightness' attribute: %m"); |
60f067b4 | 398 | return EXIT_FAILURE; |
14228c0d MB |
399 | } |
400 | ||
401 | } else if (streq(argv[1], "save")) { | |
402 | const char *value; | |
403 | ||
60f067b4 JS |
404 | if (!validate_device(udev, device)) { |
405 | unlink(saved); | |
406 | return EXIT_SUCCESS; | |
407 | } | |
408 | ||
14228c0d MB |
409 | value = udev_device_get_sysattr_value(device, "brightness"); |
410 | if (!value) { | |
60f067b4 JS |
411 | log_error("Failed to read system 'brightness' attribute"); |
412 | return EXIT_FAILURE; | |
14228c0d MB |
413 | } |
414 | ||
415 | r = write_string_file(saved, value); | |
416 | if (r < 0) { | |
f47781d8 | 417 | log_error_errno(r, "Failed to write %s: %m", saved); |
60f067b4 | 418 | return EXIT_FAILURE; |
14228c0d MB |
419 | } |
420 | ||
421 | } else { | |
422 | log_error("Unknown verb %s.", argv[1]); | |
60f067b4 | 423 | return EXIT_FAILURE; |
14228c0d MB |
424 | } |
425 | ||
60f067b4 | 426 | return EXIT_SUCCESS; |
14228c0d | 427 | } |