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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 17:51:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 17:51:51 +0000 |
commit | b0e30ceba2288eab10c6ff7be0ac0cb05a9ed0b7 (patch) | |
tree | 9f1d8a08a8cbd19d28ec2d31027f8a7ccd90de0d /plugins/power/gsd-backlight-helper.c | |
parent | Initial commit. (diff) | |
download | gnome-settings-daemon-upstream/43.0.tar.xz gnome-settings-daemon-upstream/43.0.zip |
Adding upstream version 43.0.upstream/43.0upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'plugins/power/gsd-backlight-helper.c')
-rw-r--r-- | plugins/power/gsd-backlight-helper.c | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/plugins/power/gsd-backlight-helper.c b/plugins/power/gsd-backlight-helper.c new file mode 100644 index 0000000..f0fbbb5 --- /dev/null +++ b/plugins/power/gsd-backlight-helper.c @@ -0,0 +1,149 @@ +/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- + * + * Copyright (C) 2018 Benjamin Berg <bberg@redhat.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 <stdlib.h> +#include <dirent.h> +#include <errno.h> +#include <string.h> +#include <libgen.h> +#include <stdio.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <unistd.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 + +#ifndef __linux__ +#error "gsd-backlight-helper does not work on non-Linux" +#endif + +static void +usage(int argc, char *argv[]) +{ + fprintf (stderr, "Usage: %s device brightness\n", argv[0]); + fprintf (stderr, " device: The backlight directory starting with \"/sys/class/backlight/\"\n"); + fprintf (stderr, " brightness: The new brightness to write\n"); +} + +int +main (int argc, char *argv[]) +{ + char tmp[512]; + char *device = NULL; + int fd, len, res; + int uid, euid; + int brightness; + int result = GSD_BACKLIGHT_HELPER_EXIT_CODE_FAILED; + DIR *dp = NULL; + struct dirent *ep; + + /* check calling UID */ + uid = getuid (); + euid = geteuid (); + if (uid != 0 || euid != 0) { + fprintf (stderr, "This program can only be used by the root user\n"); + result = GSD_BACKLIGHT_HELPER_EXIT_CODE_INVALID_USER; + goto done; + } + + if (argc != 3) { + fprintf (stderr, "Error: Need to be called with exactly two arguments\n"); + usage (argc, argv); + result = GSD_BACKLIGHT_HELPER_EXIT_CODE_ARGUMENTS_INVALID; + goto done; + } + + errno = 0; + brightness = strtol (argv[2], NULL, 0); + if (errno) { + fprintf (stderr, "Error: Invalid brightness argument (%d: %s)\n", errno, strerror (errno)); + usage (argc, argv); + goto done; + } + + dp = opendir ("/sys/class/backlight"); + if (dp == NULL) { + fprintf (stderr, "Error: Could not open /sys/class/backlight (%d: %s)\n", errno, strerror (errno)); + result = GSD_BACKLIGHT_HELPER_EXIT_CODE_FAILED; + goto done; + } + + /* May be NULL if the path cannot be resolved */ + device = realpath (argv[1], NULL); + + while ((ep = readdir (dp))) { + char *path; + + if (ep->d_name[0] == '.') + continue; + + /* Leave room for "/brightness" */ + snprintf (tmp, sizeof(tmp) - 11, "/sys/class/backlight/%s", ep->d_name); + path = realpath (tmp, NULL); + if (path && device && strcmp (path, device) == 0) { + free (path); + strcat (tmp, "/brightness"); + + fd = open (tmp, O_WRONLY); + if (fd < 0) { + fprintf (stderr, "Error: Could not open brightness sysfs file (%d: %s)\n", errno, strerror(errno)); + result = GSD_BACKLIGHT_HELPER_EXIT_CODE_FAILED; + goto done; + } + + len = snprintf (tmp, sizeof(tmp), "%d", brightness); + if ((res = write (fd, tmp, len)) != len) { + if (res == -1) + fprintf (stderr, "Error: Writing to file (%d: %s)\n", errno, strerror(errno)); + else + fprintf (stderr, "Error: Wrote the wrong length (%d of %d bytes)!\n", res, len); + + close (fd); + result = GSD_BACKLIGHT_HELPER_EXIT_CODE_FAILED; + goto done; + } + close (fd); + + result = GSD_BACKLIGHT_HELPER_EXIT_CODE_SUCCESS; + goto done; + } else { + free (path); + } + } + + result = GSD_BACKLIGHT_HELPER_EXIT_CODE_FAILED; + fprintf (stderr, "Error: Could not find the specified backlight \"%s\"\n", argv[1]); + +done: + if (device) + free (device); + if (dp) + closedir (dp); + + return result; +} + |