rexy712/rexbacklight
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Works with multiple backlights now

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This commit is contained in:
rexy712 2018-01-12 16:06:48 -08:00
parent 20e7754359
commit 1bfcc97d03
4 changed files with 151 additions and 68 deletions
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3
TODO Normal file
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@ -0,0 +1,3 @@
Individual device control
Query backlight percentage (get)
allow fade in and fade out

1
brightness Normal file
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@ -0,0 +1 @@
0

2
makefile
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@ -9,6 +9,8 @@ rexbacklight: rexbacklight.c
install:
install -m4711 -o root -g root -s rexbacklight /usr/bin/rexbacklight
.PHONY: uninstall
rm /usr/bin/rexbacklight
.PHONY: clean
clean:
rm rexbacklight

199
rexbacklight.c
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@ -21,8 +21,12 @@
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <dirent.h>
#include <errno.h>
void usage(void){
static const char* backlight_dir = "/sys/class/backlight/";
void usage(int exit_val){
fprintf(stderr, "Usage: rexbacklight [option]\n\n");
fprintf(stderr, "Options:\n");
@ -33,13 +37,15 @@ void usage(void){
fprintf(stderr, " max\n");
fprintf(stderr, " min\n");
if(!exit_val){
fprintf(stderr, "\nrexbacklight Copyright (C) 2018 rexy712\n");
fprintf(stderr, "This program comes with ABSOLUTELY NO WARRANTY.\n");
fprintf(stderr, "This is free software, and you are welcome to redistribute it\n");
fprintf(stderr, "under certain conditions; see the GNU GPLv3 for details.\n");
fprintf(stderr, "A copy of the GPLv3 is available with the source in the file 'LICENSE'\n");
}
exit(-1);
exit(exit_val);
}
int check_valid_files(const char* f1, const char* f2){
@ -63,6 +69,47 @@ int check_valid_files(const char* f1, const char* f2){
return 0;
}
struct string_array{
char** list;
int size;
};
//Get a list of backlight devices in sysfs
struct string_array get_backlight_sources(void){
DIR* fd;
struct dirent* dir;
fd = opendir(backlight_dir);
if(!fd){
fprintf(stderr, "Unable to open '%s' for reading!\n", backlight_dir);
return (struct string_array){.list = NULL, .size = 0};
}
char** list = malloc(sizeof(const char*) * 8);
int i;
for(i = 0;(dir = readdir(fd));){
if(!strcmp(dir->d_name, ".") || !strcmp(dir->d_name, "..")){
continue;
}
list[i] = malloc(strlen(dir->d_name) + 1);
strcpy(list[i], dir->d_name);
i++;
}
closedir(fd);
return (struct string_array){.list = list, .size = i};
}
void free_string_array(struct string_array* s){
for(int i = 0;i < s->size;i++)
free(s->list[i]);
free(s->list);
}
int get_brightness(const char* file){
FILE* bright = fopen(file, "r");
char buff[127];
@ -79,89 +126,119 @@ int get_brightness(const char* file){
return atof(buff);
}
int process_arg(char* arg, float min, float current, float max){
//Amount to inc/dec
int delta = delta = max * atof(arg + 1) / 100.0;
//Increment
if(arg[0] == '+'){
delta = delta + current;
if(delta >= max)
return max;
else{
return delta;
}
//Decrement
}else if(arg[0] == '-'){
delta = current - delta;
if(delta <= min)
return min;
else
return delta;
//Directly set
}else if(arg[0] == '='){
if(delta >= max)
return max;
else if(delta <= min)
return min;
else
return delta;
//Set to minimum plus one (so backlight is actually on!)
}else if(!strcmp("min", arg)){
return min + 1;
//Turn off backlight
}else if(!strcmp("off", arg)){
return min;
//Set to maximum
}else if(!strcmp("max", arg)){
return max;
//Unknown option
}else{
usage(-1);
}
return current;
}
//argv[1] shall be [+-=]<percentage>|min|max|off
int main(int argc, char** argv){
const char* backlight_file = "/sys/class/backlight/intel_backlight/brightness";
const char* max_backlight_file = "/sys/class/backlight/intel_backlight/max_brightness";
const char* backlight_file = "brightness";
const char* max_backlight_file = "max_brightness";
//Make sure we have an argument and it is at least 2 characters long
if(argc < 2 || strlen(argv[1]) < 2)
usage();
else if(!strcmp(argv[1], "--help"))
usage();
if(argc < 2 || !strcmp(argv[1], "--help"))
usage(0);
else if(strlen(argv[1]) < 2)
usage(-1);
//Gain access to sysfs files
if(setuid(0)){
fprintf(stderr, "Unable to setuid to 0!\n");
return -3;
}
//Make sure we aren't in a chroot environment (prevents writing to a file we don't want to!)
if(check_valid_files("/", "/proc/1/root")){
fprintf(stderr, "No chroot today\n");
return -4;
}
//Min brightness is just 0, so set it up front
float min_brightness = 0;
float max_brightness = get_brightness(max_backlight_file);
float current_brightness = get_brightness(backlight_file);
//Now that we've verified we're in a safe environment to do the work,
//Let's get everything set up!
//Amount to inc/dec
int delta;
if(strlen(argv[1]) > 0)
delta = max_brightness * atof(argv[1] + 1) / 100.0;
else
delta = 0;
//Acquire a list of backlight devices in sysfs
struct string_array backlight_names = get_backlight_sources();
if(backlight_names.size == 0){
fprintf(stderr, "No backlights devices found!\n");
return -1;
}
//save our starting directory so we can change to each backlight directory
const char* starting_dir = getcwd(NULL, 0);
if(chdir(backlight_dir)){
fprintf(stderr, "Unable to read backlight sysfs directory!\n");
return -2;
}
//Set all backlight sources to the requested percentage
for(int i = 0;i < backlight_names.size;i++){
if(chdir(backlight_names.list[i])){
fprintf(stderr, "Unable to open backlight directory \"%s%s\"!\n", backlight_dir, backlight_names.list[i]);
continue;
}
//Open brightness file for writing
int out = process_arg(argv[1], 0, get_brightness(backlight_file), get_brightness(max_backlight_file));
FILE* bright = fopen(backlight_file, "w+");
if(!bright){
fprintf(stderr, "Unable to open brightness file \"%s\" for writing!\n", backlight_file);
return 1;
continue;
}
fprintf(bright, "%d", out);
//Increment
if(argv[1][0] == '+'){
delta = delta + current_brightness;
if(delta >= max_brightness)
fprintf(bright, "%d", (int)max_brightness);
else{
fprintf(bright, "%d", delta);
}
//Decrement
}else if(argv[1][0] == '-'){
delta = current_brightness - delta;
if(delta <= min_brightness)
fprintf(bright, "%d", (int)min_brightness);
else
fprintf(bright, "%d", delta);
//Directly set
}else if(argv[1][0] == '='){
if(delta >= max_brightness)
fprintf(bright, "%d", (int)max_brightness);
else if(delta <= min_brightness)
fprintf(bright, "%d", (int)min_brightness);
else
fprintf(bright, "%d", delta);
//Set to minimum plus one (so backlight is actually on!)
}else if(!strcmp("min", argv[1])){
fprintf(bright, "%d", (int)(min_brightness + 1));
//Turn off backlight
}else if(!strcmp("off", argv[1])){
fprintf(bright, "%d", (int)min_brightness);
//Set to maximum
}else if(!strcmp("max", argv[1])){
fprintf(bright, "%d", (int)max_brightness);
//Unknown option
}else{
fclose(bright);
usage();
}
fclose(bright);
free_string_array(&backlight_names);
if(chdir(starting_dir)){
fprintf(stderr, "Could not return to starting directory!\nWas the directory moved/deleted?\n");
if(chdir(getenv("HOME")) || chdir("/")){
return -5;
}
}
return 0;
}