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/*
* Application interface library for the AVIRT driver
*
* avirt-config.c - Main AVIRT configuration via configfs
*
* Copyright (C) 2018 Fiberdyne Systems Pty Ltd
* Author: Mark Farrugia <mark.farrugia@fiberdyne.com.au>
*
* 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 2 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/>.
*/
#include <avirt/avirt.h>
#include <stdbool.h>
#include <stdio.h>
#include <alsa/asoundlib.h>
#include <sys/stat.h>
#include <sys/mount.h>
#define AVIRT_CONFIGFS_PATH_STREAMS "/config/snd-avirt/streams/"
#define AVIRT_CONFIGFS_PATH_MAXLEN 64
#define AVIRT_ERROR(errmsg) \
fprintf(stderr, "AVIRT ERROR: %s\n", errmsg);
#define AVIRT_ERROR_V(fmt, args...) \
fprintf(stderr, "AVIRT ERROR: " fmt "\n", ##args);
#define AVIRT_DEBUG_ON
#ifdef AVIRT_DEBUG_ON
# define AVIRT_DEBUG(debugmsg) \
fprintf(stderr, "AVIRT DEBUG: %s\n", debugmsg);
# define AVIRT_DEBUG_V(fmt, args...) \
fprintf(stderr, "[%s]: AVIRT DEBUG: " fmt "\n", __func__, ##args);
#endif
/**
* Checks whether the configfs filesystem is mounted
*/
#define IS_CONFIGFS_MOUNTED() \
do { \
int err; \
if (!configfs_mounted) { \
err = mount_configfs(); \
if (err < 0) return err; \
} \
} while (0)
/**
* Write the given formatted string to a file given by path
*/
#define WRITE_TO_PATH(path, fmt, args...) \
do { \
FILE *fd = fopen(path, "w"); \
if (!fd) { \
AVIRT_ERROR_V("Failed to open file at '%s'", path); \
return -EPERM; \
} \
fprintf(fd, fmt, ##args); \
fclose(fd); \
} while (0)
static bool configfs_mounted = false;
static bool card_sealed = false;
static int mount_configfs()
{
int err;
char fsline[100];
bool configfs_supported = false;
FILE *procfs;
struct stat st = {0};
// Check for /proc/filesystem for configfs support
procfs = fopen("/proc/filesystems", "r");
if (!procfs)
return -1;
while (fgets(fsline, 100, procfs))
{
if (!strstr(fsline, "configfs"))
continue;
configfs_supported = true;
}
if (!configfs_supported)
{
AVIRT_ERROR("configfs is not supported !");
return -1;
}
// Check whether /config dir exists, if not, create it
if (stat("/config", &st) == -1)
mkdir("/config", S_IRWXU | S_IRWXG | S_IRWXO);
err = mount("none", "/config", "configfs", 0, NULL);
if (!err)
{
AVIRT_DEBUG("Successfully mounted configfs");
configfs_mounted = true;
}
else
AVIRT_ERROR("Failed to mount configfs filesystem!");
return err;
}
int snd_avirt_stream_new(const char *name, unsigned int channels, int direction,
const char *map)
{
int err;
char path[AVIRT_CONFIGFS_PATH_MAXLEN];
char path_attr[AVIRT_CONFIGFS_PATH_MAXLEN];
IS_CONFIGFS_MOUNTED();
// Check if card is already sealed
if (card_sealed)
{
AVIRT_ERROR("Card is already sealed!");
return -EPERM;
}
// This indicates to AVIRT the direction of the stream
strcpy(path, AVIRT_CONFIGFS_PATH_STREAMS);
switch (direction) {
case SND_PCM_STREAM_PLAYBACK:
strcat(path, "playback_");
break;
case SND_PCM_STREAM_CAPTURE:
strcat(path, "capture_");
break;
default:
return -EINVAL;
}
if ((AVIRT_CONFIGFS_PATH_MAXLEN - strlen(path)) < strlen(name))
{
AVIRT_ERROR_V("Cannot create stream '%s' since name is too long!", name);
return -ENOMEM;
}
strcat(path, name);
err = mkdir(path, S_IRWXU | S_IRWXG | S_IRWXO);
if (err < 0)
{
AVIRT_ERROR_V("Cannot create stream '%s' at directory '%s'", name, path);
return err;
}
// Write channels
strcpy(path_attr, path);
strcat(path_attr, "/channels");
WRITE_TO_PATH(path_attr, "%d", channels);
if (map)
{
// Write mapping
strcpy(path_attr, path);
strcat(path_attr, "/map");
WRITE_TO_PATH(path_attr, "%s", map);
}
AVIRT_DEBUG_V("Created stream: %s", name);
return 0;
}
int snd_avirt_card_seal()
{
char path_sealed[AVIRT_CONFIGFS_PATH_MAXLEN];
// Check if card is already sealed
if (card_sealed)
{
AVIRT_ERROR("Card is already sealed!");
return -EPERM;
}
IS_CONFIGFS_MOUNTED();
strcpy(path_sealed, AVIRT_CONFIGFS_PATH_STREAMS);
strcat(path_sealed, "/sealed");
WRITE_TO_PATH(path_sealed, "%d", 1);
AVIRT_DEBUG("Card sealed!");
card_sealed = true;
return 0;
}
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