aboutsummaryrefslogtreecommitdiffstats
path: root/binding/radio_impl_rtlsdr.c
blob: 9a1c492b25fd5da654f3624323a025f30e32d862 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
/*
 * Copyright (C) 2017,2018 Konsulko Group
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include <unistd.h>
#include <pthread.h>
#include <sys/stat.h>
#include <errno.h>
#include <glib.h>
#define AFB_BINDING_VERSION 2
#include <afb/afb-binding.h>

#include "radio_impl.h"

#define HELPER_NAME	"rtl_fm_helper"
#define HELPER_MAX	PATH_MAX + 64

// Structure to describe FM band plans, all values in Hz.
typedef struct {
	char *name;
	uint32_t min;
	uint32_t max;
	uint32_t step;
} fm_band_plan_t;

static fm_band_plan_t known_fm_band_plans[5] = {
	{ .name = "US", .min = 87900000, .max = 107900000, .step = 200000 },
	{ .name = "JP", .min = 76000000, .max = 95000000, .step = 100000 },
	{ .name = "EU", .min = 87500000, .max = 108000000, .step = 50000 },
	{ .name = "ITU-1", .min = 87500000, .max = 108000000, .step = 50000 },
	{ .name = "ITU-2", .min = 87900000, .max = 107900000, .step = 50000 }
};

static unsigned int bandplan;
static pid_t helper_pid;
static int helper_in;
static int helper_out;
static pthread_mutex_t helper_mutex = PTHREAD_MUTEX_INITIALIZER;
static bool present;
static bool active;
static bool scanning;
static uint32_t current_frequency;
static radio_freq_callback_t freq_callback;
static void *freq_callback_data;

static uint32_t rtlsdr_get_min_frequency(radio_band_t band);
static void rtlsdr_set_frequency(uint32_t frequency);
static void rtlsdr_scan_stop(void);

/*
 * Bi-directional popen implementation
 * Based on one of the versions given in:
 *
 * https://stackoverflow.com/questions/12778672/killing-process-that-has-been-created-with-popen2
 */
static pid_t popen2(char *command, int *in_fd, int *out_fd)
{
	int     pin[2], pout[2];
	pid_t   pid;

	if(out_fd != NULL) {
		if(pipe(pin) != 0)
			return -1;
	}
	if(in_fd != NULL) {
		if (pipe(pout) != 0) {
			if(out_fd != NULL) {
				close(pin[0]);
				close(pin[1]);
			}
			return -1;
		}
	}

	pid = fork();
	if(pid < 0) {
		if(out_fd != NULL) {
			close(pin[0]);
			close(pin[1]);
		}
		if(in_fd != NULL) {
			close(pout[0]);
			close(pout[1]);
		}
		return pid;
	}
	if(pid == 0) {
		if(out_fd != NULL) {
			close(pin[1]);
			dup2(pin[0], 0);
		}
		if(in_fd != NULL) {
			close(pout[0]);
			dup2(pout[1], 1);
		}
		execlp(command, command, NULL);
		perror("Error:");
		exit(1);
	}
	if(in_fd != NULL) {
		close(pout[1]);
		*in_fd = pout[0];
	}
	if(out_fd != NULL) {
		close(pin[0]);
		*out_fd = pin[1];
	}
	return pid;
}

static int rtlsdr_init(const char *output)
{
	GKeyFile *conf_file;
	char *value_str;
	char *rootdir;
	char *helper_path;

	if(present)
		return 0;

	// Load settings from configuration file if it exists
	conf_file = g_key_file_new();
	if(conf_file &&
	   g_key_file_load_from_dirs(conf_file,
				     "AGL.conf",
				     (const gchar**) g_get_system_config_dirs(),
				     NULL,
				     G_KEY_FILE_KEEP_COMMENTS,
				     NULL) == TRUE) {

		// Set band plan if it is specified
		value_str = g_key_file_get_string(conf_file,
						  "radio",
						  "fmbandplan",
						  NULL);
		if(value_str) {
			unsigned int i;
			for(i = 0;
			    i < sizeof(known_fm_band_plans) / sizeof(fm_band_plan_t);
			    i++) {
				if(!strcasecmp(value_str, known_fm_band_plans[i].name)) {
					bandplan = i;
					break;
				}
			}
		}
	}

	// Start off with minimum bandplan frequency
	current_frequency = rtlsdr_get_min_frequency(BAND_FM);

	rootdir = getenv("AFM_APP_INSTALL_DIR");
	if(!rootdir)
		return -1;

	// Run helper to detect adapter
	helper_path = malloc(HELPER_MAX);
	if(!helper_path)
		return -ENOMEM;
	if(snprintf(helper_path, HELPER_MAX, "%s/bin/%s --detect", rootdir, HELPER_NAME) == HELPER_MAX) {
		AFB_ERROR("Could not create command for \"%s --detect\"", HELPER_NAME);
		return -EINVAL;
	}
	if(system(helper_path) != 0) {
		free(helper_path);
		return -1;
	}

	if(output) {
		// Indicate desired output to helper
		AFB_INFO("Setting RADIO_OUTPUT=%s", output);
		setenv("RADIO_OUTPUT", output, 1);
	}

	// Run helper
	if(snprintf(helper_path, PATH_MAX, "%s/bin/%s", rootdir, HELPER_NAME) == PATH_MAX) {
		AFB_ERROR("Could not create path to %s", HELPER_NAME);
		return -EINVAL;
	}
	helper_pid = popen2(helper_path, &helper_out, &helper_in);
	if(helper_pid < 0) {
		AFB_ERROR("Could not run %s!", HELPER_NAME);
		return -1;
	}
	AFB_DEBUG("%s started", HELPER_NAME);
	free(helper_path);

	present = true;
	rtlsdr_set_frequency(current_frequency);

	return 0;
}

static uint32_t rtlsdr_get_frequency(void)
{
	return current_frequency;
}

static void rtlsdr_set_frequency(uint32_t frequency)
{
	char cmd[64];
	char output[128];
	bool found = false;
	ssize_t rc;
	uint32_t n;

	if(!present)
		return;

	if(frequency < known_fm_band_plans[bandplan].min ||
	   frequency > known_fm_band_plans[bandplan].max)
		return;

	if(scanning)
		rtlsdr_scan_stop();

	current_frequency = frequency;
	sprintf(cmd, "F=%u\n", frequency);
	pthread_mutex_lock(&helper_mutex);
	rc = write(helper_in, cmd, strlen(cmd));
	if(rc < 0) {
		pthread_mutex_unlock(&helper_mutex);
		return;
	}
	while(!found) {
		rc = read(helper_out, output, 128);
		if(rc <= 0)
			break;
		if(rc == 128)
			rc = 127;
		output[rc] = '\0';
		if(output[0] == 'F') {
			if(sscanf(output, "F=%u\n", &n) == 1) {
				if(freq_callback)
					freq_callback(n, freq_callback_data);
				found = true;
			}
		}
	}
	pthread_mutex_unlock(&helper_mutex);
}

static void rtlsdr_set_frequency_callback(radio_freq_callback_t callback,
					  void *data)
{
	freq_callback = callback;
	freq_callback_data = data;
}

static radio_band_t rtlsdr_get_band(void)
{
	// We only support FM
	return BAND_FM;
}

static void rtlsdr_set_band(radio_band_t band)
{
	// We only support FM, so do nothing
}

static int rtlsdr_band_supported(radio_band_t band)
{
	if(band == BAND_FM)
		return 1;
	return 0;
}

static uint32_t rtlsdr_get_min_frequency(radio_band_t band)
{
	return known_fm_band_plans[bandplan].min;
}

static uint32_t rtlsdr_get_max_frequency(radio_band_t band)
{
	return known_fm_band_plans[bandplan].max;
}

static uint32_t rtlsdr_get_frequency_step(radio_band_t band)
{
	uint32_t ret = 0;

	switch (band) {
	case BAND_AM:
		ret = 1000; // 1 kHz
		break;
	case BAND_FM:
		ret = known_fm_band_plans[bandplan].step;
		break;
	default:
		break;
	}
	return ret;
}

static void rtlsdr_start(void)
{
	if(!present)
		return;

	if(!active) {
		ssize_t rc;
		char cmd[64];

		sprintf(cmd, "START\n");
		pthread_mutex_lock(&helper_mutex);
		rc = write(helper_in, cmd, strlen(cmd));
		pthread_mutex_unlock(&helper_mutex);
		if(rc < 0)
			return;
		active = true;
	}
}

static void rtlsdr_stop(void)
{
	if(!present)
		return;

	if(active) {
		char cmd[64];

		active = false;
		sprintf(cmd, "STOP\n");
		pthread_mutex_lock(&helper_mutex);
		write(helper_in, cmd, strlen(cmd));
		pthread_mutex_unlock(&helper_mutex);
	}
}

static void rtlsdr_scan_start(radio_scan_direction_t direction,
			      radio_scan_callback_t callback,
			      void *data)
{
	ssize_t rc;
	char cmd[64];
	char output[128];
	bool found = false;
	uint32_t n;

	if(!active || scanning)
		return;

	scanning = true;
	sprintf(cmd, "S=%s\n", direction == SCAN_FORWARD ? "UP" : "DOWN");
	pthread_mutex_lock(&helper_mutex);
	if(!scanning) {
		pthread_mutex_unlock(&helper_mutex);
		return;
	}
	rc = write(helper_in, cmd, strlen(cmd));
	pthread_mutex_unlock(&helper_mutex);
	if(rc < 0)
		return;
	while(!found) {
		pthread_mutex_lock(&helper_mutex);
		if(!scanning) {
			pthread_mutex_unlock(&helper_mutex);
			break;
		}
		rc = read(helper_out, output, 128);
		pthread_mutex_unlock(&helper_mutex);
		if(rc <= 0)
			break;
		if(rc == 128)
			rc = 127;
		output[rc] = '\0';
		if(output[0] == 'F') {
			if(sscanf(output, "F=%u\n", &n) == 1) {
				current_frequency = n;
				if(freq_callback)
					freq_callback(n, freq_callback_data);
			}
		}
		if(output[0] == 'S') {
			if(sscanf(output, "S=%u\n", &n) == 1) {
				if(callback)
					callback(n, data);
				found = true;
				scanning = false;
			}
		}
	}
}

static void rtlsdr_scan_stop(void)
{
	char cmd[64];

	sprintf(cmd, "S=STOP\n");
	pthread_mutex_lock(&helper_mutex);
	scanning = false;
	write(helper_in, cmd, strlen(cmd));
	pthread_mutex_unlock(&helper_mutex);
}

static radio_stereo_mode_t rtlsdr_get_stereo_mode(void)
{
	// We only support stereo
	return STEREO;
}

static void rtlsdr_set_stereo_mode(radio_stereo_mode_t mode)
{
	// We only support stereo, so do nothing
}

radio_impl_ops_t rtlsdr_impl_ops = {
	.name = "RTL-SDR USB adapter",
	.init = rtlsdr_init,
	.get_frequency = rtlsdr_get_frequency,
	.set_frequency = rtlsdr_set_frequency,
	.set_frequency_callback = rtlsdr_set_frequency_callback,
	.get_band = rtlsdr_get_band,
	.set_band = rtlsdr_set_band,
	.band_supported = rtlsdr_band_supported,
	.get_min_frequency = rtlsdr_get_min_frequency,
	.get_max_frequency = rtlsdr_get_max_frequency,
	.get_frequency_step = rtlsdr_get_frequency_step,
	.start = rtlsdr_start,
	.stop = rtlsdr_stop,
	.scan_start = rtlsdr_scan_start,
	.scan_stop = rtlsdr_scan_stop,
	.get_stereo_mode = rtlsdr_get_stereo_mode,
	.set_stereo_mode = rtlsdr_set_stereo_mode
};