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#define _GNU_SOURCE
#include <libbacklight.h>
#include <stdio.h>
#include <sys/types.h>
#include <dirent.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <malloc.h>
#include <string.h>
static const char *output_names[] = { "None",
"VGA",
"DVI",
"DVI",
"DVI",
"Composite",
"TV",
"LVDS",
"CTV",
"DIN",
"DP",
"HDMI",
"HDMI",
};
static long backlight_get(struct backlight *backlight, char *node)
{
char buffer[100];
char *path;
int fd;
long value, ret;
asprintf(&path, "%s/%s", backlight->path, node);
fd = open(path, O_RDONLY);
if (fd < 0) {
ret = -1;
goto out;
}
ret = read(fd, &buffer, sizeof(buffer));
if (ret < 1) {
ret = -1;
goto out;
}
value = strtol(buffer, NULL, 10);
ret = value;
out:
close(fd);
if (path)
free(path);
return ret;
}
long backlight_get_brightness(struct backlight *backlight)
{
return backlight_get(backlight, "brightness");
}
long backlight_get_max_brightness(struct backlight *backlight)
{
return backlight_get(backlight, "max_brightness");
}
long backlight_get_actual_brightness(struct backlight *backlight)
{
return backlight_get(backlight, "actual_brightness");
}
long backlight_set_brightness(struct backlight *backlight, long brightness)
{
char *path;
char *buffer = NULL;
int fd;
long value, ret;
asprintf(&path, "%s/%s", backlight->path, "brightness");
fd = open(path, O_RDWR);
if (fd < 0) {
ret = -1;
goto out;
}
ret = read(fd, &buffer, sizeof(buffer));
if (ret < 1) {
ret = -1;
goto out;
}
asprintf(&buffer, "%ld", brightness);
ret = write(fd, buffer, strlen(buffer));
if (ret < 0) {
ret = -1;
goto out;
}
ret = backlight_get_brightness(backlight);
out:
if (buffer)
free(buffer);
if (path)
free(path);
close(fd);
return ret;
}
struct backlight *backlight_init(struct pci_device *dev, int card,
int connector_type, int connector_type_id)
{
char *pci_name;
char *drm_name;
char *chosen_path = NULL;
DIR *backlights;
struct dirent *entry;
enum backlight_type type = 0;
char buffer[100];
struct backlight *backlight;
asprintf(&pci_name, "%04x:%02x:%02x.%d", dev->domain, dev->bus,
dev->dev, dev->func);
asprintf(&drm_name, "card%d-%s-%d", card, output_names[connector_type],
connector_type_id);
backlights = opendir("/sys/class/backlight");
if (!backlights)
return NULL;
while ((entry = readdir(backlights))) {
char *backlight_path;
char *parent;
char *path;
enum backlight_type entry_type;
int fd, ret;
if (entry->d_name[0] == '.')
continue;
asprintf(&backlight_path, "%s/%s", "/sys/class/backlight",
entry->d_name);
asprintf(&path, "%s/%s", backlight_path, "type");
fd = open(path, O_RDONLY);
if (fd < 0)
goto out;
ret = read (fd, &buffer, sizeof(buffer));
close (fd);
if (ret < 1)
goto out;
buffer[ret] = '\0';
if (!strncmp(buffer, "raw\n", sizeof(buffer)))
entry_type = BACKLIGHT_RAW;
else if (!strncmp(buffer, "platform\n", sizeof(buffer)))
entry_type = BACKLIGHT_PLATFORM;
else if (!strncmp(buffer, "firmware\n", sizeof(buffer)))
entry_type = BACKLIGHT_FIRMWARE;
else
goto out;
free (path);
asprintf(&path, "%s/%s", backlight_path, "device");
ret = readlink(path, buffer, sizeof(buffer));
if (ret < 0)
goto out;
parent = basename(buffer);
if (entry_type == BACKLIGHT_RAW) {
if (strcmp(drm_name, parent) &&
strcmp(pci_name, parent)) {
goto out;
}
}
if (entry_type == BACKLIGHT_FIRMWARE) {
/* Older kernels won't provide a valid path here... */
unsigned int domain, bus, device, function;
ret = sscanf(parent, "%04x:%02x:%02x.%u", &domain, &bus,
&device, &function);
if (ret == 4) {
if (strcmp(pci_name, parent))
goto out;
}
}
if (entry_type < type)
goto out;
type = entry_type;
if (chosen_path)
free(chosen_path);
chosen_path = strdup(backlight_path);
out:
free(backlight_path);
free(path);
}
if (!chosen_path)
return NULL;
backlight = malloc(sizeof(struct backlight));
if (!backlight)
goto err;
backlight->path = chosen_path;
backlight->type = type;
backlight->max_brightness = backlight_get_max_brightness(backlight);
if (backlight->max_brightness < 0)
goto err;
backlight->brightness = backlight_get_actual_brightness(backlight);
if (backlight->brightness < 0)
goto err;
return backlight;
err:
if (chosen_path)
free(chosen_path);
free (backlight);
return NULL;
}
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