/**
* libgamma — Display server abstraction layer for gamma ramp adjustments
* Copyright © 2014 Mattias Andrée (maandree@member.fsf.org)
*
* This library 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 library 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 library. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef HAVE_GAMMA_METHOD_LINUX_DRM
# error Compiling gamma-linux-drm.c without HAVE_GAMMA_METHOD_LINUX_DRM
#endif
#define _GNU_SOURCE
#include "gamma-linux-drm.h"
#include "libgamma-error.h"
#include <limits.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <grp.h>
#include <unistd.h>
#include <stdio.h>
#include <xf86drm.h>
#include <xf86drmMode.h>
#ifndef O_CLOEXEC
# define O_CLOEXEC 02000000
#endif
#ifndef NGROUPS_MAX
# define NGROUPS_MAX 65536
#endif
#ifndef PATH_MAX
# define PATH_MAX 4096
#endif
/**
* Graphics card data for the Direct Rendering Manager adjustment method
*/
typedef struct libgamma_drm_card_data
{
/**
* File descriptor for the connection to the graphics card
*/
int fd;
/**
* The graphics card's mode resources
*/
drmModeRes* res;
} libgamma_drm_card_data_t;
/**
* Return the capabilities of the adjustment method
*
* @param this The data structure to fill with the method's capabilities
*/
void libgamma_linux_drm_method_capabilities(libgamma_method_capabilities_t* restrict this)
{
this->crtc_information = CRTC_INFO_EDID
| CRTC_INFO_WIDTH_MM
| CRTC_INFO_HEIGHT_MM
| CRTC_INFO_WIDTH_MM_EDID
| CRTC_INFO_HEIGHT_MM_EDID
| CRTC_INFO_GAMMA_SIZE
| CRTC_INFO_GAMMA_DEPTH
| CRTC_INFO_SUBPIXEL_ORDER
| CRTC_INFO_CONNECTOR_NAME
| CRTC_INFO_CONNECTOR_TYPE
| CRTC_INFO_GAMMA;
this->default_site_known = 1;
this->multiple_sites = 0;
this->multiple_partitions = 1;
this->multiple_crtcs = 1;
this->partitions_are_graphics_cards = 1;
this->site_restore = 0;
this->partition_restore = 0;
this->crtc_restore = 0;
this->identical_gamma_sizes = 1;
this->fixed_gamma_size = 0;
this->fixed_gamma_depth = 1;
this->real = 1;
this->fake = 0;
}
/**
* Initialise an allocated site state
*
* @param this The site state to initialise
* @param site The site identifier, unless it is `NULL` it must a
* `free`:able. One the state is destroyed the library
* will attempt to free it. There you should not free
* it yourself, and it must not be a string constant
* or allocate on the stack. Note however that it will
* not be free:d if this function fails.
* @return Zero on success, otherwise (negative) the value of an
* error identifier provided by this library
*/
int libgamma_linux_drm_site_initialise(libgamma_site_state_t* restrict this,
char* restrict site)
{
char pathname[PATH_MAX];
struct stat _attr;
if (site != NULL)
return LIBGAMMA_NO_SUCH_SITE;
/* Count the number of available graphics cards by
* stat:ing there existence in an API filesystem. */
this->partitions_available = 0;
for (;;)
{
snprintf(pathname, sizeof(pathname) / sizeof(char),
DRM_DEV_NAME, DRM_DIR_NAME, (int)(this->partitions_available));
if (stat(pathname, &_attr))
break;
if (this->partitions_available++ > INT_MAX)
return LIBGAMMA_IMPOSSIBLE_AMOUNT;
}
return 0;
}
/**
* Release all resources held by a site state
*
* @param this The site state
*/
void libgamma_linux_drm_site_destroy(libgamma_site_state_t* restrict this)
{
(void) this;
}
/**
* Restore the gamma ramps all CRTCS with a site to the system settings
*
* @param this The site state
* @return Zero on success, otherwise (negative) the value of an
* error identifier provided by this library
*/
int libgamma_linux_drm_site_restore(libgamma_site_state_t* restrict this)
{
(void) this;
return errno = ENOTSUP, LIBGAMMA_ERRNO_SET;
}
/**
* Initialise an allocated partition state
*
* @param this The partition state to initialise
* @param site The site state for the site that the partition belongs to
* @param partition The the index of the partition within the site
* @return Zero on success, otherwise (negative) the value of an
* error identifier provided by this library
*/
int libgamma_linux_drm_partition_initialise(libgamma_partition_state_t* restrict this,
libgamma_site_state_t* restrict site, size_t partition)
{ /* FIXME: This function is too large. */
int rc = 0;
libgamma_drm_card_data_t* data;
char pathname[PATH_MAX];
(void) site;
/* Check for partition index overflow. */
if (partition > INT_MAX)
return LIBGAMMA_NO_SUCH_PARTITION;
/* Allocate and initialise graphics card data. */
this->data = NULL;
data = malloc(sizeof(libgamma_drm_card_data_t));
if (data == NULL)
return LIBGAMMA_ERRNO_SET;
data->fd = -1;
data->res = NULL;
/* Get the pathname for the graphics card. */
snprintf(pathname, sizeof(pathname) / sizeof(char),
DRM_DEV_NAME, DRM_DIR_NAME, (int)partition);
/* Acquire access to the graphics card. */
data->fd = open(pathname, O_RDWR | O_CLOEXEC);
if (data->fd < 0)
{
if ((errno == ENXIO) || (errno == ENODEV))
rc = LIBGAMMA_NO_SUCH_PARTITION;
else if (errno == EACCES)
{
struct stat attr;
int r;
r = stat(pathname, &attr);
rc = LIBGAMMA_NO_SUCH_PARTITION;
#define __test(R, W) ((attr.st_mode & (R | W)) == (R | W))
if (r)
rc = errno == EACCES ? LIBGAMMA_NO_SUCH_PARTITION : LIBGAMMA_ERRNO_SET;
else if ((attr.st_uid == geteuid() && __test(S_IRUSR, S_IWUSR)) ||
(attr.st_gid == getegid() && __test(S_IRGRP, S_IWGRP)) ||
__test(S_IROTH, S_IWOTH))
rc = LIBGAMMA_DEVICE_ACCESS_FAILED;
else if (attr.st_gid == 0 /* root group */ || __test(S_IRGRP, S_IWGRP))
rc = LIBGAMMA_DEVICE_RESTRICTED;
else
{
gid_t supplemental_groups[NGROUPS_MAX];
struct group* group;
int i, n;
n = getgroups(NGROUPS_MAX, supplemental_groups);
if (n < 0)
{
rc = LIBGAMMA_ERRNO_SET;
goto fail_data;
}
for (i = 0; i < n; i++)
if (supplemental_groups[i] == attr.st_gid)
break;
if (i != n)
{
rc = LIBGAMMA_DEVICE_ACCESS_FAILED;
goto fail_data;
}
rc = LIBGAMMA_DEVICE_REQUIRE_GROUP;
errno = 0;
group = getgrgid(attr.st_gid); /* TODO: Not thread-safe. */
libgamma_group_gid = attr.st_gid;
libgamma_group_name = group != NULL ? group->gr_name : NULL;
}
#undef __test
}
else
rc = LIBGAMMA_ERRNO_SET;
goto fail_data;
}
/* Acquire mode resources. */
data->res = drmModeGetResources(data->fd);
if (data->res == NULL)
{
rc = LIBGAMMA_ACQUIRING_MODE_RESOURCES_FAILED;
goto fail_fd;
}
/* Get the number of CRTC:s that are available in the partition. */
if (data->res->count_crtcs < 0)
{
rc = LIBGAMMA_NEGATIVE_CRTC_COUNT;
goto fail_res;
}
this->crtcs_available = (size_t)(data->res->count_crtcs);
return 0;
fail_res:
drmModeFreeResources(data->res);
fail_fd:
close(data->fd);
fail_data:
free(data);
return rc;
}
/**
* Release all resources held by a partition state
*
* @param this The partition state
*/
void libgamma_linux_drm_partition_destroy(libgamma_partition_state_t* restrict this)
{
libgamma_drm_card_data_t* data = this->data;
if (data->res != NULL)
drmModeFreeResources(data->res);
if (data->fd >= 0)
close(data->fd);
free(data);
}
/**
* Restore the gamma ramps all CRTCS with a partition to the system settings
*
* @param this The partition state
* @return Zero on success, otherwise (negative) the value of an
* error identifier provided by this library
*/
int libgamma_linux_drm_partition_restore(libgamma_partition_state_t* restrict this)
{
(void) this;
return errno = ENOTSUP, LIBGAMMA_ERRNO_SET;
}
/**
* Initialise an allocated CRTC state
*
* @param this The CRTC state to initialise
* @param partition The partition state for the partition that the CRTC belongs to
* @param crtc The the index of the CRTC within the site
* @return Zero on success, otherwise (negative) the value of an
* error identifier provided by this library
*/
int libgamma_linux_drm_crtc_initialise(libgamma_crtc_state_t* restrict this,
libgamma_partition_state_t* restrict partition, size_t crtc)
{
libgamma_drm_card_data_t* card;
uint32_t crtc_id;
if (crtc >= partition->crtcs_available)
return LIBGAMMA_NO_SUCH_CRTC;
card = partition->data;
crtc_id = card->res->crtcs[crtc];
this->data = (void*)(size_t)crtc_id;
return 0;
}
/**
* Release all resources held by a CRTC state
*
* @param this The CRTC state
*/
void libgamma_linux_drm_crtc_destroy(libgamma_crtc_state_t* restrict this)
{
(void) this;
}
/**
* Restore the gamma ramps for a CRTC to the system settings for that CRTC
*
* @param this The CRTC state
* @return Zero on success, otherwise (negative) the value of an
* error identifier provided by this library
*/
int libgamma_linux_drm_crtc_restore(libgamma_crtc_state_t* restrict this)
{
(void) this;
return errno = ENOTSUP, LIBGAMMA_ERRNO_SET;
}
/**
* Read information about a CRTC
*
* @param this Instance of a data structure to fill with the information about the CRTC
* @param crtc The state of the CRTC whose information should be read
* @param fields OR:ed identifiers for the information about the CRTC that should be read
* @return Zero on success, -1 on error. On error refer to the error reports in `this`.
*/
int libgamma_linux_drm_get_crtc_information(libgamma_crtc_information_t* restrict this,
libgamma_crtc_state_t* restrict crtc, int32_t fields)
{
}
/**
* Get current the gamma ramps for a CRTC, 16-bit gamma-depth version
*
* @param this The CRTC state
* @param ramps The gamma ramps to fill with the current values
* @return Zero on success, otherwise (negative) the value of an
* error identifier provided by this library
*/
int libgamma_linux_drm_crtc_get_gamma_ramps(libgamma_crtc_state_t* restrict this,
libgamma_gamma_ramps_t* restrict ramps)
{
libgamma_drm_card_data_t* card = this->partition->data;
int r;
#ifdef DEBUG
if ((ramps->red_size != ramps->green_size) ||
(ramps->red_size != ramps->blue_size))
return LIBGAMMA_MIXED_GAMMA_RAMP_SIZE;
#endif
r = drmModeCrtcGetGamma(card->fd, (uint32_t)(this->crtc), (uint32_t)(ramps->red_size),
ramps->red, ramps->green, ramps->blue);
return r ? LIBGAMMA_GAMMA_RAMP_READ_FAILED : 0;
}
/**
* Set the gamma ramps for a CRTC, 16-bit gamma-depth version
*
* @param this The CRTC state
* @param ramps The gamma ramps to apply
* @return Zero on success, otherwise (negative) the value of an
* error identifier provided by this library
*/
int libgamma_linux_drm_crtc_set_gamma_ramps(libgamma_crtc_state_t* restrict this,
libgamma_gamma_ramps_t ramps)
{
libgamma_drm_card_data_t* card = this->partition->data;
int r;
#ifdef DEBUG
if ((ramps.red_size != ramps.green_size) ||
(ramps.red_size != ramps.blue_size))
return LIBGAMMA_MIXED_GAMMA_RAMP_SIZE;
#endif
r = drmModeCrtcSetGamma(card->fd, (uint32_t)(size_t)(this->data),
(uint32_t)(ramps.red_size), ramps.red, ramps.green, ramps.blue);
if (r)
switch (errno)
{
case EACCES:
case EAGAIN:
case EIO:
/* Permission denied errors must be ignored, because we do not
* have permission to do this while a display server is active.
* We are also checking for some other error codes just in case. */
case EBUSY:
case EINPROGRESS:
/* It is hard to find documentation for DRM (in fact all of this is
* just based on the functions names and some testing,) perhaps we
* could get this if we are updating to fast. */
break;
case EBADF:
case ENODEV:
case ENXIO:
/* XXX: I have not actually tested removing my graphics card or,
* monitor but I imagine either of these is what would happen. */
return LIBGAMMA_GRAPHICS_CARD_REMOVED;
default:
return LIBGAMMA_ERRNO_SET;
}
return 0;
}
