./move.sh

1 files changed, 434 insertions, 0 deletions

diff --git a/src/systemd-backlight/backlight.c b/src/systemd-backlight/backlight.c
new file mode 100644
index 0000000000..45be135a23
--- /dev/null
+++ b/src/systemd-backlight/backlight.c
@@ -0,0 +1,434 @@
+/***
+  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 "libudev.h"
+
+#include "alloc-util.h"
+#include "def.h"
+#include "escape.h"
+#include "fileio.h"
+#include "mkdir.h"
+#include "parse-util.h"
+#include "proc-cmdline.h"
+#include "string-util.h"
+#include "udev-util.h"
+#include "util.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() == 0)
+                        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, WRITE_STRING_FILE_CREATE);
+                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;
+}