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/**
* crt-calibrator – Calibration utility for CRT monitors
* Copyright © 2014 Mattias Andrée (maandree@member.fsf.org)
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*/
#include "drmgamma.h"
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <fcntl.h>
/**
* Close on exec flag for `open`
*/
#ifndef O_CLOEXEC
# define O_CLOEXEC 02000000
#endif
/**
* The number of elements to allocates to a buffer for a DRM device pathname
*/
#define DRM_DEV_NAME_MAX_LEN \
((sizeof(DRM_DEV_NAME) + sizeof(DRM_DIR_NAME)) / sizeof(char) + 3 * sizeof(int))
/**
* Figure out how many graphics cards there are on the system
*
* @return The number of graphics cards on the system
*/
size_t drm_card_count(void)
{
char buf[DRM_DEV_NAME_MAX_LEN];
size_t count = 0;
for (;; count++)
{
sprintf(buf, DRM_DEV_NAME, DRM_DIR_NAME, (int)count);
if (access(buf, F_OK) < 0)
return count;
}
}
/**
* Acquire access to a graphics card
*
* @param index The index of the graphics card
* @param card Graphics card information to fill in
* @return Zero on success, -1 on error
*/
int drm_card_open(size_t index, drm_card_t* restrict card)
{
char buf[DRM_DEV_NAME_MAX_LEN];
int old_errno;
card->fd = -1;
card->res = NULL;
sprintf(buf, DRM_DEV_NAME, DRM_DIR_NAME, (int)index);
card->fd = open(buf, O_RDWR | O_CLOEXEC);
if (card->fd == -1)
goto fail;
card->res = drmModeGetResources(card->fd);
if (card->res == NULL)
goto fail;
card->crtc_count = (size_t)(card->res->count_crtcs);
return 0;
fail:
old_errno = errno;
drm_card_close(card);
errno = old_errno;
return -1;
}
/**
* Release access to a graphics card
*
* @param card The graphics card information
*/
void drm_card_close(drm_card_t* restrict card)
{
if (card->res != NULL)
drmModeFreeResources(card->res), card->res = NULL;
if (card->fd != -1)
close(card->fd), card->fd = -1;
}
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