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3731acf1 LP |
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 | ||
3731acf1 LP |
22 | #include "util.h" |
23 | #include "mkdir.h" | |
24 | #include "fileio.h" | |
1ca208fb ZJS |
25 | #include "libudev.h" |
26 | #include "udev-util.h" | |
3731acf1 | 27 | |
0f4ba83c LP |
28 | static struct udev_device *find_pci_or_platform_parent(struct udev_device *device) { |
29 | struct udev_device *parent; | |
30 | const char *subsystem, *sysname; | |
31 | ||
32 | assert(device); | |
33 | ||
34 | parent = udev_device_get_parent(device); | |
35 | if (!parent) | |
36 | return NULL; | |
37 | ||
38 | subsystem = udev_device_get_subsystem(parent); | |
39 | if (!subsystem) | |
40 | return NULL; | |
41 | ||
42 | sysname = udev_device_get_sysname(parent); | |
43 | if (!sysname) | |
44 | return NULL; | |
45 | ||
46 | if (streq(subsystem, "drm")) { | |
47 | const char *c; | |
48 | ||
49 | c = startswith(sysname, "card"); | |
50 | if (!c) | |
51 | return NULL; | |
52 | ||
53 | c += strspn(c, "0123456789"); | |
54 | if (*c == '-') { | |
55 | /* A connector DRM device, let's ignore all but LVDS and eDP! */ | |
56 | ||
57 | if (!startswith(c, "-LVDS-") && | |
58 | !startswith(c, "-Embedded DisplayPort-")) | |
59 | return NULL; | |
60 | } | |
61 | ||
62 | } else if (streq(subsystem, "pci")) { | |
63 | const char *value; | |
64 | ||
65 | value = udev_device_get_sysattr_value(parent, "class"); | |
66 | if (value) { | |
67 | unsigned long class; | |
68 | ||
69 | if (safe_atolu(value, &class) < 0) { | |
70 | log_warning("Cannot parse PCI class %s of device %s:%s.", value, subsystem, sysname); | |
71 | return NULL; | |
72 | } | |
73 | ||
74 | /* Graphics card */ | |
75 | if (class == 0x30000) | |
76 | return parent; | |
77 | } | |
78 | ||
79 | } else if (streq(subsystem, "platform")) | |
80 | return parent; | |
81 | ||
82 | return find_pci_or_platform_parent(parent); | |
83 | } | |
84 | ||
85 | static bool same_device(struct udev_device *a, struct udev_device *b) { | |
86 | assert(a); | |
87 | assert(b); | |
88 | ||
89 | if (!streq_ptr(udev_device_get_subsystem(a), udev_device_get_subsystem(b))) | |
90 | return false; | |
91 | ||
92 | if (!streq_ptr(udev_device_get_sysname(a), udev_device_get_sysname(b))) | |
93 | return false; | |
94 | ||
95 | return true; | |
96 | } | |
97 | ||
98 | static bool validate_device(struct udev *udev, struct udev_device *device) { | |
99 | _cleanup_udev_enumerate_unref_ struct udev_enumerate *enumerate = NULL; | |
100 | struct udev_list_entry *item = NULL, *first = NULL; | |
101 | struct udev_device *parent; | |
102 | const char *v, *subsystem; | |
103 | int r; | |
104 | ||
105 | assert(udev); | |
106 | assert(device); | |
107 | ||
108 | /* Verify whether we should actually care for a specific | |
109 | * backlight device. For backlight devices there might be | |
110 | * multiple ways to access the same control: "firmware" | |
111 | * (i.e. ACPI), "platform" (i.e. via the machine's EC) and | |
112 | * "raw" (via the graphics card). In general we should prefer | |
113 | * "firmware" (i.e. ACPI) or "platform" access over "raw" | |
114 | * access, in order not to confuse the BIOS/EC, and | |
115 | * compatibility with possible low-level hotkey handling of | |
116 | * screen brightness. The kernel will already make sure to | |
117 | * expose only one of "firmware" and "platform" for the same | |
118 | * device to userspace. However, we still need to make sure | |
119 | * that we use "raw" only if no "firmware" or "platform" | |
120 | * device for the same device exists. */ | |
121 | ||
122 | subsystem = udev_device_get_subsystem(device); | |
123 | if (!streq_ptr(subsystem, "backlight")) | |
124 | return true; | |
125 | ||
126 | v = udev_device_get_sysattr_value(device, "type"); | |
127 | if (!streq_ptr(v, "raw")) | |
128 | return true; | |
129 | ||
130 | parent = find_pci_or_platform_parent(device); | |
131 | if (!parent) | |
132 | return true; | |
133 | ||
134 | subsystem = udev_device_get_subsystem(parent); | |
135 | if (!subsystem) | |
136 | return true; | |
137 | ||
138 | enumerate = udev_enumerate_new(udev); | |
139 | if (!enumerate) | |
140 | return true; | |
141 | ||
142 | r = udev_enumerate_add_match_subsystem(enumerate, "backlight"); | |
143 | if (r < 0) | |
144 | return true; | |
145 | ||
146 | r = udev_enumerate_scan_devices(enumerate); | |
147 | if (r < 0) | |
148 | return true; | |
149 | ||
150 | first = udev_enumerate_get_list_entry(enumerate); | |
151 | udev_list_entry_foreach(item, first) { | |
152 | _cleanup_udev_device_unref_ struct udev_device *other; | |
153 | struct udev_device *other_parent; | |
154 | const char *other_subsystem; | |
155 | ||
156 | other = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item)); | |
157 | if (!other) | |
158 | return true; | |
159 | ||
160 | if (same_device(device, other)) | |
161 | continue; | |
162 | ||
163 | v = udev_device_get_sysattr_value(other, "type"); | |
164 | if (!streq_ptr(v, "platform") && !streq_ptr(v, "firmware")) | |
165 | continue; | |
166 | ||
167 | /* OK, so there's another backlight device, and it's a | |
168 | * platform or firmware device, so, let's see if we | |
169 | * can verify it belongs to the same device as | |
170 | * ours. */ | |
171 | other_parent = find_pci_or_platform_parent(other); | |
172 | if (!other_parent) | |
173 | continue; | |
174 | ||
175 | if (same_device(parent, other_parent)) { | |
176 | /* Both have the same PCI parent, that means | |
177 | * we are out. */ | |
178 | log_debug("Skipping backlight device %s, since backlight device %s is on same PCI device and, takes precedence.", udev_device_get_sysname(device), udev_device_get_sysname(other)); | |
179 | return false; | |
180 | } | |
181 | ||
182 | other_subsystem = udev_device_get_subsystem(other_parent); | |
183 | if (streq_ptr(other_subsystem, "platform") && streq_ptr(subsystem, "pci")) { | |
184 | /* The other is connected to the platform bus | |
185 | * and we are a PCI device, that also means we | |
186 | * are out. */ | |
187 | log_debug("Skipping backlight device %s, since backlight device %s is a platform device and takes precedence.", udev_device_get_sysname(device), udev_device_get_sysname(other)); | |
188 | return false; | |
189 | } | |
190 | } | |
191 | ||
192 | return true; | |
193 | } | |
194 | ||
3731acf1 | 195 | int main(int argc, char *argv[]) { |
1ca208fb ZJS |
196 | _cleanup_udev_unref_ struct udev *udev = NULL; |
197 | _cleanup_udev_device_unref_ struct udev_device *device = NULL; | |
be3f52f4 LP |
198 | _cleanup_free_ char *saved = NULL, *ss = NULL, *escaped_ss = NULL, *escaped_sysname = NULL, *escaped_path_id = NULL; |
199 | const char *sysname, *path_id; | |
3731acf1 LP |
200 | int r; |
201 | ||
202 | if (argc != 3) { | |
203 | log_error("This program requires two arguments."); | |
204 | return EXIT_FAILURE; | |
205 | } | |
206 | ||
207 | log_set_target(LOG_TARGET_AUTO); | |
208 | log_parse_environment(); | |
209 | log_open(); | |
210 | ||
211 | umask(0022); | |
212 | ||
ef5bfcf6 | 213 | r = mkdir_p("/var/lib/systemd/backlight", 0755); |
3731acf1 LP |
214 | if (r < 0) { |
215 | log_error("Failed to create backlight directory: %s", strerror(-r)); | |
1ca208fb | 216 | return EXIT_FAILURE; |
3731acf1 LP |
217 | } |
218 | ||
219 | udev = udev_new(); | |
220 | if (!udev) { | |
1ca208fb ZJS |
221 | log_oom(); |
222 | return EXIT_FAILURE; | |
3731acf1 LP |
223 | } |
224 | ||
0f4ba83c LP |
225 | sysname = strchr(argv[2], ':'); |
226 | if (!sysname) { | |
227 | log_error("Requires pair of subsystem and sysname for specifying backlight device."); | |
228 | return EXIT_FAILURE; | |
229 | } | |
230 | ||
231 | ss = strndup(argv[2], sysname - argv[2]); | |
232 | if (!ss) { | |
233 | log_oom(); | |
234 | return EXIT_FAILURE; | |
235 | } | |
236 | ||
237 | sysname++; | |
238 | ||
239 | if (!streq(ss, "backlight") && !streq(ss, "leds")) { | |
240 | log_error("Not a backlight or LED device: '%s:%s'", ss, sysname); | |
241 | return EXIT_FAILURE; | |
242 | } | |
243 | ||
875c6e1b | 244 | errno = 0; |
0f4ba83c | 245 | device = udev_device_new_from_subsystem_sysname(udev, ss, sysname); |
3731acf1 | 246 | if (!device) { |
1ca208fb | 247 | if (errno != 0) |
0f4ba83c | 248 | log_error("Failed to get backlight or LED device '%s:%s': %m", ss, sysname); |
1ca208fb | 249 | else |
0f4ba83c | 250 | log_oom(); |
3731acf1 | 251 | |
1ca208fb | 252 | return EXIT_FAILURE; |
3731acf1 LP |
253 | } |
254 | ||
be3f52f4 LP |
255 | escaped_ss = cescape(ss); |
256 | if (!escaped_ss) { | |
257 | log_oom(); | |
258 | return EXIT_FAILURE; | |
259 | } | |
260 | ||
261 | escaped_sysname = cescape(sysname); | |
262 | if (!escaped_sysname) { | |
263 | log_oom(); | |
264 | return EXIT_FAILURE; | |
265 | } | |
266 | ||
267 | path_id = udev_device_get_property_value(device, "ID_PATH"); | |
268 | if (path_id) { | |
269 | escaped_path_id = cescape(path_id); | |
270 | if (!escaped_path_id) { | |
271 | log_oom(); | |
272 | return EXIT_FAILURE; | |
273 | } | |
274 | ||
275 | saved = strjoin("/var/lib/systemd/backlight/", escaped_path_id, ":", escaped_ss, ":", escaped_sysname, NULL); | |
276 | } else | |
277 | saved = strjoin("/var/lib/systemd/backlight/", escaped_ss, ":", escaped_sysname, NULL); | |
278 | ||
3731acf1 | 279 | if (!saved) { |
1ca208fb ZJS |
280 | log_oom(); |
281 | return EXIT_FAILURE; | |
3731acf1 LP |
282 | } |
283 | ||
0f4ba83c LP |
284 | /* If there are multiple conflicting backlight devices, then |
285 | * their probing at boot-time might happen in any order. This | |
286 | * means the validity checking of the device then is not | |
287 | * reliable, since it might not see other devices conflicting | |
288 | * with a specific backlight. To deal with this we will | |
289 | * actively delete backlight state files at shutdown (where | |
290 | * device probing should be complete), so that the validity | |
291 | * check at boot time doesn't have to be reliable. */ | |
292 | ||
3731acf1 LP |
293 | if (streq(argv[1], "load")) { |
294 | _cleanup_free_ char *value = NULL; | |
295 | ||
0f4ba83c LP |
296 | if (!validate_device(udev, device)) |
297 | return EXIT_SUCCESS; | |
298 | ||
3731acf1 LP |
299 | r = read_one_line_file(saved, &value); |
300 | if (r < 0) { | |
301 | ||
1ca208fb ZJS |
302 | if (r == -ENOENT) |
303 | return EXIT_SUCCESS; | |
3731acf1 LP |
304 | |
305 | log_error("Failed to read %s: %s", saved, strerror(-r)); | |
1ca208fb | 306 | return EXIT_FAILURE; |
3731acf1 LP |
307 | } |
308 | ||
309 | r = udev_device_set_sysattr_value(device, "brightness", value); | |
310 | if (r < 0) { | |
311 | log_error("Failed to write system attribute: %s", strerror(-r)); | |
1ca208fb | 312 | return EXIT_FAILURE; |
3731acf1 LP |
313 | } |
314 | ||
315 | } else if (streq(argv[1], "save")) { | |
316 | const char *value; | |
317 | ||
0f4ba83c LP |
318 | if (!validate_device(udev, device)) { |
319 | unlink(saved); | |
320 | return EXIT_SUCCESS; | |
321 | } | |
322 | ||
3731acf1 LP |
323 | value = udev_device_get_sysattr_value(device, "brightness"); |
324 | if (!value) { | |
325 | log_error("Failed to read system attribute: %s", strerror(-r)); | |
1ca208fb | 326 | return EXIT_FAILURE; |
3731acf1 LP |
327 | } |
328 | ||
329 | r = write_string_file(saved, value); | |
330 | if (r < 0) { | |
331 | log_error("Failed to write %s: %s", saved, strerror(-r)); | |
1ca208fb | 332 | return EXIT_FAILURE; |
3731acf1 LP |
333 | } |
334 | ||
335 | } else { | |
336 | log_error("Unknown verb %s.", argv[1]); | |
1ca208fb | 337 | return EXIT_FAILURE; |
3731acf1 LP |
338 | } |
339 | ||
1ca208fb | 340 | return EXIT_SUCCESS; |
3731acf1 | 341 | } |