+++ /dev/null
-/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
-
-/***
- This file is part of systemd.
-
- Copyright 2013 Lennart Poettering
-
- systemd is free software; you can redistribute it and/or modify it
- under the terms of the GNU Lesser General Public License as published by
- the Free Software Foundation; either version 2.1 of the License, or
- (at your option) any later version.
-
- systemd is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public License
- along with systemd; If not, see <http://www.gnu.org/licenses/>.
-***/
-
-#include "util.h"
-#include "mkdir.h"
-#include "fileio.h"
-#include "libudev.h"
-#include "udev-util.h"
-#include "def.h"
-
-static struct udev_device *find_pci_or_platform_parent(struct udev_device *device) {
- struct udev_device *parent;
- const char *subsystem, *sysname;
-
- assert(device);
-
- parent = udev_device_get_parent(device);
- if (!parent)
- return NULL;
-
- subsystem = udev_device_get_subsystem(parent);
- if (!subsystem)
- return NULL;
-
- sysname = udev_device_get_sysname(parent);
- if (!sysname)
- return NULL;
-
- if (streq(subsystem, "drm")) {
- const char *c;
-
- c = startswith(sysname, "card");
- if (!c)
- return NULL;
-
- c += strspn(c, DIGITS);
- if (*c == '-') {
- /* A connector DRM device, let's ignore all but LVDS and eDP! */
-
- if (!startswith(c, "-LVDS-") &&
- !startswith(c, "-Embedded DisplayPort-"))
- return NULL;
- }
-
- } else if (streq(subsystem, "pci")) {
- const char *value;
-
- value = udev_device_get_sysattr_value(parent, "class");
- if (value) {
- unsigned long class = 0;
-
- if (safe_atolu(value, &class) < 0) {
- log_warning("Cannot parse PCI class %s of device %s:%s.",
- value, subsystem, sysname);
- return NULL;
- }
-
- /* Graphics card */
- if (class == 0x30000)
- return parent;
- }
-
- } else if (streq(subsystem, "platform"))
- return parent;
-
- return find_pci_or_platform_parent(parent);
-}
-
-static bool same_device(struct udev_device *a, struct udev_device *b) {
- assert(a);
- assert(b);
-
- if (!streq_ptr(udev_device_get_subsystem(a), udev_device_get_subsystem(b)))
- return false;
-
- if (!streq_ptr(udev_device_get_sysname(a), udev_device_get_sysname(b)))
- return false;
-
- return true;
-}
-
-static bool validate_device(struct udev *udev, struct udev_device *device) {
- _cleanup_udev_enumerate_unref_ struct udev_enumerate *enumerate = NULL;
- struct udev_list_entry *item = NULL, *first = NULL;
- struct udev_device *parent;
- const char *v, *subsystem;
- int r;
-
- assert(udev);
- assert(device);
-
- /* Verify whether we should actually care for a specific
- * backlight device. For backlight devices there might be
- * multiple ways to access the same control: "firmware"
- * (i.e. ACPI), "platform" (i.e. via the machine's EC) and
- * "raw" (via the graphics card). In general we should prefer
- * "firmware" (i.e. ACPI) or "platform" access over "raw"
- * access, in order not to confuse the BIOS/EC, and
- * compatibility with possible low-level hotkey handling of
- * screen brightness. The kernel will already make sure to
- * expose only one of "firmware" and "platform" for the same
- * device to userspace. However, we still need to make sure
- * that we use "raw" only if no "firmware" or "platform"
- * device for the same device exists. */
-
- subsystem = udev_device_get_subsystem(device);
- if (!streq_ptr(subsystem, "backlight"))
- return true;
-
- v = udev_device_get_sysattr_value(device, "type");
- if (!streq_ptr(v, "raw"))
- return true;
-
- parent = find_pci_or_platform_parent(device);
- if (!parent)
- return true;
-
- subsystem = udev_device_get_subsystem(parent);
- if (!subsystem)
- return true;
-
- enumerate = udev_enumerate_new(udev);
- if (!enumerate)
- return true;
-
- r = udev_enumerate_add_match_subsystem(enumerate, "backlight");
- if (r < 0)
- return true;
-
- r = udev_enumerate_scan_devices(enumerate);
- if (r < 0)
- return true;
-
- first = udev_enumerate_get_list_entry(enumerate);
- udev_list_entry_foreach(item, first) {
- _cleanup_udev_device_unref_ struct udev_device *other;
- struct udev_device *other_parent;
- const char *other_subsystem;
-
- other = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item));
- if (!other)
- return true;
-
- if (same_device(device, other))
- continue;
-
- v = udev_device_get_sysattr_value(other, "type");
- if (!streq_ptr(v, "platform") && !streq_ptr(v, "firmware"))
- continue;
-
- /* OK, so there's another backlight device, and it's a
- * platform or firmware device, so, let's see if we
- * can verify it belongs to the same device as
- * ours. */
- other_parent = find_pci_or_platform_parent(other);
- if (!other_parent)
- continue;
-
- if (same_device(parent, other_parent)) {
- /* Both have the same PCI parent, that means
- * we are out. */
- log_debug("Skipping backlight device %s, since device %s is on same PCI device and takes precedence.",
- udev_device_get_sysname(device),
- udev_device_get_sysname(other));
- return false;
- }
-
- other_subsystem = udev_device_get_subsystem(other_parent);
- if (streq_ptr(other_subsystem, "platform") && streq_ptr(subsystem, "pci")) {
- /* The other is connected to the platform bus
- * and we are a PCI device, that also means we
- * are out. */
- log_debug("Skipping backlight device %s, since device %s is a platform device and takes precedence.",
- udev_device_get_sysname(device),
- udev_device_get_sysname(other));
- return false;
- }
- }
-
- return true;
-}
-
-static unsigned get_max_brightness(struct udev_device *device) {
- int r;
- const char *max_brightness_str;
- unsigned max_brightness;
-
- max_brightness_str = udev_device_get_sysattr_value(device, "max_brightness");
- if (!max_brightness_str) {
- log_warning("Failed to read 'max_brightness' attribute.");
- return 0;
- }
-
- r = safe_atou(max_brightness_str, &max_brightness);
- if (r < 0) {
- log_warning_errno(r, "Failed to parse 'max_brightness' \"%s\": %m", max_brightness_str);
- return 0;
- }
-
- if (max_brightness <= 0) {
- log_warning("Maximum brightness is 0, ignoring device.");
- return 0;
- }
-
- return max_brightness;
-}
-
-/* Some systems turn the backlight all the way off at the lowest levels.
- * clamp_brightness clamps the saved brightness to at least 1 or 5% of
- * max_brightness in case of 'backlight' subsystem. This avoids preserving
- * an unreadably dim screen, which would otherwise force the user to
- * disable state restoration. */
-static void clamp_brightness(struct udev_device *device, char **value, unsigned max_brightness) {
- int r;
- unsigned brightness, new_brightness, min_brightness;
- const char *subsystem;
-
- r = safe_atou(*value, &brightness);
- if (r < 0) {
- log_warning_errno(r, "Failed to parse brightness \"%s\": %m", *value);
- return;
- }
-
- subsystem = udev_device_get_subsystem(device);
- if (streq_ptr(subsystem, "backlight"))
- min_brightness = MAX(1U, max_brightness/20);
- else
- min_brightness = 0;
-
- new_brightness = CLAMP(brightness, min_brightness, max_brightness);
- if (new_brightness != brightness) {
- char *old_value = *value;
-
- r = asprintf(value, "%u", new_brightness);
- if (r < 0) {
- log_oom();
- return;
- }
-
- log_info("Saved brightness %s %s to %s.", old_value,
- new_brightness > brightness ?
- "too low; increasing" : "too high; decreasing",
- *value);
-
- free(old_value);
- }
-}
-
-int main(int argc, char *argv[]) {
- _cleanup_udev_unref_ struct udev *udev = NULL;
- _cleanup_udev_device_unref_ struct udev_device *device = NULL;
- _cleanup_free_ char *saved = NULL, *ss = NULL, *escaped_ss = NULL, *escaped_sysname = NULL, *escaped_path_id = NULL;
- const char *sysname, *path_id;
- unsigned max_brightness;
- int r;
-
- if (argc != 3) {
- log_error("This program requires two arguments.");
- return EXIT_FAILURE;
- }
-
- log_set_target(LOG_TARGET_AUTO);
- log_parse_environment();
- log_open();
-
- umask(0022);
-
- r = mkdir_p("/var/lib/systemd/backlight", 0755);
- if (r < 0) {
- log_error_errno(r, "Failed to create backlight directory /var/lib/systemd/backlight: %m");
- return EXIT_FAILURE;
- }
-
- udev = udev_new();
- if (!udev) {
- log_oom();
- return EXIT_FAILURE;
- }
-
- sysname = strchr(argv[2], ':');
- if (!sysname) {
- log_error("Requires a subsystem and sysname pair specifying a backlight device.");
- return EXIT_FAILURE;
- }
-
- ss = strndup(argv[2], sysname - argv[2]);
- if (!ss) {
- log_oom();
- return EXIT_FAILURE;
- }
-
- sysname++;
-
- if (!streq(ss, "backlight") && !streq(ss, "leds")) {
- log_error("Not a backlight or LED device: '%s:%s'", ss, sysname);
- return EXIT_FAILURE;
- }
-
- errno = 0;
- device = udev_device_new_from_subsystem_sysname(udev, ss, sysname);
- if (!device) {
- if (errno != 0)
- log_error_errno(errno, "Failed to get backlight or LED device '%s:%s': %m", ss, sysname);
- else
- log_oom();
-
- return EXIT_FAILURE;
- }
-
- /* If max_brightness is 0, then there is no actual backlight
- * device. This happens on desktops with Asus mainboards
- * that load the eeepc-wmi module.
- */
- max_brightness = get_max_brightness(device);
- if (max_brightness == 0)
- return EXIT_SUCCESS;
-
- escaped_ss = cescape(ss);
- if (!escaped_ss) {
- log_oom();
- return EXIT_FAILURE;
- }
-
- escaped_sysname = cescape(sysname);
- if (!escaped_sysname) {
- log_oom();
- return EXIT_FAILURE;
- }
-
- path_id = udev_device_get_property_value(device, "ID_PATH");
- if (path_id) {
- escaped_path_id = cescape(path_id);
- if (!escaped_path_id) {
- log_oom();
- return EXIT_FAILURE;
- }
-
- saved = strjoin("/var/lib/systemd/backlight/", escaped_path_id, ":", escaped_ss, ":", escaped_sysname, NULL);
- } else
- saved = strjoin("/var/lib/systemd/backlight/", escaped_ss, ":", escaped_sysname, NULL);
-
- if (!saved) {
- log_oom();
- return EXIT_FAILURE;
- }
-
- /* If there are multiple conflicting backlight devices, then
- * their probing at boot-time might happen in any order. This
- * means the validity checking of the device then is not
- * reliable, since it might not see other devices conflicting
- * with a specific backlight. To deal with this, we will
- * actively delete backlight state files at shutdown (where
- * device probing should be complete), so that the validity
- * check at boot time doesn't have to be reliable. */
-
- if (streq(argv[1], "load")) {
- _cleanup_free_ char *value = NULL;
- const char *clamp;
-
- if (!shall_restore_state())
- return EXIT_SUCCESS;
-
- if (!validate_device(udev, device))
- return EXIT_SUCCESS;
-
- r = read_one_line_file(saved, &value);
- if (r < 0) {
-
- if (r == -ENOENT)
- return EXIT_SUCCESS;
-
- log_error_errno(r, "Failed to read %s: %m", saved);
- return EXIT_FAILURE;
- }
-
- clamp = udev_device_get_property_value(device, "ID_BACKLIGHT_CLAMP");
- if (!clamp || parse_boolean(clamp) != 0) /* default to clamping */
- clamp_brightness(device, &value, max_brightness);
-
- r = udev_device_set_sysattr_value(device, "brightness", value);
- if (r < 0) {
- log_error_errno(r, "Failed to write system 'brightness' attribute: %m");
- return EXIT_FAILURE;
- }
-
- } else if (streq(argv[1], "save")) {
- const char *value;
-
- if (!validate_device(udev, device)) {
- unlink(saved);
- return EXIT_SUCCESS;
- }
-
- value = udev_device_get_sysattr_value(device, "brightness");
- if (!value) {
- log_error("Failed to read system 'brightness' attribute");
- return EXIT_FAILURE;
- }
-
- r = write_string_file(saved, value);
- if (r < 0) {
- log_error_errno(r, "Failed to write %s: %m", saved);
- return EXIT_FAILURE;
- }
-
- } else {
- log_error("Unknown verb %s.", argv[1]);
- return EXIT_FAILURE;
- }
-
- return EXIT_SUCCESS;
-}
~ianmdlvl / elogind.git / commitdiff