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/*
* BSD Zero Clause License
*
* Copyright (c) 2022 Thomas Voss
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
* OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <dirent.h>
#include <fcntl.h>
#include <unistd.h>
#include "lux.h"
static int getdir(void);
int
luxinit(lux_t *disp)
{
/* Set the default values for the luxdisp struct. We want to be as lazy
* as possible, so we don't bother with __bstream and __max yet. We do
* need __dirfd though.
*/
*disp = (lux_t) {
.__bstream = NULL,
.__max = -1,
.__dirfd = getdir()
};
return disp->__dirfd;
}
int
getdir(void)
{
int fd, dfd;
struct dirent *dp;
DIR *dir;
/* To get the file descriptor for the directory where all the brightness
* files are located, we first need to open LUX_BACKLIGHT_DIR which is
* the directory where the backlight directories are located. Then we
* need to get a DIR* of that directory and get the 3rd entry. We need
* the third because the fist and second are the . and .. folders.
* Finally we open the folder so that we have a file descriptor we can
* return.
*/
if ((dfd = open(LUX_BACKLIGHT_DIR, O_RDONLY)) == -1)
return -1;
if ((dir = fdopendir(dfd)) == NULL) {
close(dfd);
return -1;
}
if ((dp = readdir(dir)) == NULL
|| (dp = readdir(dir)) == NULL
|| (dp = readdir(dir)) == NULL
|| (fd = openat(dfd, dp->d_name, LUX_GDIR_FLAGS)) == -1)
fd = -1;
close(dfd);
closedir(dir);
return fd;
}
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