/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*-
*
* Copyright (C) 2010-2011 Richard Hughes <richard@hughsie.com>
*
* Licensed under the GNU General Public License Version 2
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "config.h"
#include <unistd.h>
#include <glib-object.h>
#include <locale.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#define GSD_BACKLIGHT_HELPER_EXIT_CODE_SUCCESS 0
#define GSD_BACKLIGHT_HELPER_EXIT_CODE_FAILED 1
#define GSD_BACKLIGHT_HELPER_EXIT_CODE_ARGUMENTS_INVALID 3
#define GSD_BACKLIGHT_HELPER_EXIT_CODE_INVALID_USER 4
#define GSD_BACKLIGHT_HELPER_SYSFS_LOCATION "/sys/class/backlight"
static gchar *
gsd_backlight_helper_get_best_backlight ()
{
gchar *filename;
guint i;
gboolean ret;
GDir *dir = NULL;
GError *error = NULL;
const gchar *first_device;
/* available kernel interfaces in priority order */
static const gchar *backlight_interfaces[] = {
"nv_backlight",
"asus_laptop",
"toshiba",
"eeepc",
"thinkpad_screen",
"acpi_video1",
"mbp_backlight",
"acpi_video0",
"fujitsu-laptop",
"nvidia_backlight",
"samsung",
NULL,
};
/* search each one */
for (i=0; backlight_interfaces[i] != NULL; i++) {
filename = g_build_filename (GSD_BACKLIGHT_HELPER_SYSFS_LOCATION,
backlight_interfaces[i], NULL);
ret = g_file_test (filename, G_FILE_TEST_EXISTS);
if (ret)
goto out;
g_free (filename);
}
/* nothing found in the ordered list */
filename = NULL;
/* find any random ones */
dir = g_dir_open (GSD_BACKLIGHT_HELPER_SYSFS_LOCATION, 0, &error);
if (dir == NULL) {
g_warning ("failed to find any devices: %s", error->message);
g_error_free (error);
goto out;
}
/* get first device if any */
first_device = g_dir_read_name (dir);
if (first_device != NULL) {
filename = g_build_filename (GSD_BACKLIGHT_HELPER_SYSFS_LOCATION,
first_device, NULL);
}
out:
if (dir != NULL)
g_dir_close (dir);
return filename;
}
static gboolean
gsd_backlight_helper_write (const gchar *filename, gint value, GError **error)
{
gchar *text = NULL;
gint retval;
gint length;
gint fd = -1;
gboolean ret = TRUE;
fd = open (filename, O_WRONLY);
if (fd < 0) {
ret = FALSE;
g_set_error (error, 1, 0, "failed to open filename: %s", filename);
goto out;
}
/* convert to text */
text = g_strdup_printf ("%i", value);
length = strlen (text);
/* write to device file */
retval = write (fd, text, length);
if (retval != length) {
ret = FALSE;
g_set_error (error, 1, 0, "writing '%s' to %s failed", text, filename);
goto out;
}
out:
if (fd >= 0)
close (fd);
g_free (text);
return ret;
}
int
main (int argc, char *argv[])
{
GOptionContext *context;
gint uid;
gint euid;
guint retval = 0;
const gchar *pkexec_uid_str;
GError *error = NULL;
gboolean ret = FALSE;
gint set_brightness = -1;
gboolean get_brightness = FALSE;
gboolean get_max_brightness = FALSE;
gchar *filename = NULL;
gchar *filename_file = NULL;
gchar *contents = NULL;
const GOptionEntry options[] = {
{ "set-brightness", '\0', 0, G_OPTION_ARG_INT, &set_brightness,
/* command line argument */
"Set the current brightness", NULL },
{ "get-brightness", '\0', 0, G_OPTION_ARG_NONE, &get_brightness,
/* command line argument */
"Get the current brightness", NULL },
{ "get-max-brightness", '\0', 0, G_OPTION_ARG_NONE, &get_max_brightness,
/* command line argument */
"Get the number of brightness levels supported", NULL },
{ NULL}
};
/* setup type system */
g_type_init ();
context = g_option_context_new (NULL);
g_option_context_set_summary (context, "GNOME Settings Daemon Backlight Helper");
g_option_context_add_main_entries (context, options, NULL);
g_option_context_parse (context, &argc, &argv, NULL);
g_option_context_free (context);
#ifndef __linux__
/* the g-s-d plugin should only call this helper on linux */
g_critical ("Attempting to call gsb-backlight-helper on non-Linux");
g_assert_not_reached ();
#endif
/* no input */
if (set_brightness == -1 && !get_brightness && !get_max_brightness) {
g_print ("%s\n", "No valid option was specified");
retval = GSD_BACKLIGHT_HELPER_EXIT_CODE_ARGUMENTS_INVALID;
goto out;
}
/* find device */
filename = gsd_backlight_helper_get_best_backlight ();
if (filename == NULL) {
g_print ("%s\n", "No backlights were found on your system");
retval = GSD_BACKLIGHT_HELPER_EXIT_CODE_INVALID_USER;
goto out;
}
/* GetBrightness */
if (get_brightness) {
filename_file = g_build_filename (filename, "brightness", NULL);
ret = g_file_get_contents (filename_file, &contents, NULL, &error);
if (!ret) {
g_print ("%s: %s\n",
"Could not get the value of the backlight",
error->message);
g_error_free (error);
retval = GSD_BACKLIGHT_HELPER_EXIT_CODE_ARGUMENTS_INVALID;
goto out;
}
/* just print the contents to stdout */
g_print ("%s", contents);
retval = GSD_BACKLIGHT_HELPER_EXIT_CODE_SUCCESS;
goto out;
}
/* GetSteps */
if (get_max_brightness) {
filename_file = g_build_filename (filename, "max_brightness", NULL);
ret = g_file_get_contents (filename_file, &contents, NULL, &error);
if (!ret) {
g_print ("%s: %s\n",
"Could not get the maximum value of the backlight",
error->message);
g_error_free (error);
retval = GSD_BACKLIGHT_HELPER_EXIT_CODE_ARGUMENTS_INVALID;
goto out;
}
/* just print the contents to stdout */
g_print ("%s", contents);
retval = GSD_BACKLIGHT_HELPER_EXIT_CODE_SUCCESS;
goto out;
}
/* get calling process */
uid = getuid ();
euid = geteuid ();
if (uid != 0 || euid != 0) {
g_print ("%s\n",
"This program can only be used by the root user");
retval = GSD_BACKLIGHT_HELPER_EXIT_CODE_ARGUMENTS_INVALID;
goto out;
}
/* check we're not being spoofed */
pkexec_uid_str = g_getenv ("PKEXEC_UID");
if (pkexec_uid_str == NULL) {
g_print ("%s\n",
"This program must only be run through pkexec");
retval = GSD_BACKLIGHT_HELPER_EXIT_CODE_INVALID_USER;
goto out;
}
/* SetBrightness */
if (set_brightness != -1) {
filename_file = g_build_filename (filename, "brightness", NULL);
ret = gsd_backlight_helper_write (filename_file, set_brightness, &error);
if (!ret) {
g_print ("%s: %s\n",
"Could not set the value of the backlight",
error->message);
g_error_free (error);
retval = GSD_BACKLIGHT_HELPER_EXIT_CODE_ARGUMENTS_INVALID;
goto out;
}
}
/* success */
retval = GSD_BACKLIGHT_HELPER_EXIT_CODE_SUCCESS;
out:
g_free (filename);
g_free (filename_file);
g_free (contents);
return retval;
}
Adv Reply
Originally Posted by rfictus
Re: Fixing screen brightness issue in Ubuntu 12.04
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