1 /*-
2 * Copyright (c) 2021 Hans Petter Selasky <hselasky@freebsd.org>
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 */
25
26 #include <sys/soundcard.h>
27
28 #include <capsicum_helpers.h>
29 #include <err.h>
30 #include <errno.h>
31 #include <fcntl.h>
32 #include <math.h>
33 #include <paths.h>
34 #include <stdbool.h>
35 #include <stdint.h>
36 #include <stdio.h>
37 #include <stdlib.h>
38 #include <string.h>
39 #include <unistd.h>
40
41 #define SAMPLE_RATE_DEF 48000 /* hz */
42 #define SAMPLE_RATE_MAX 48000 /* hz */
43 #define SAMPLE_RATE_MIN 8000 /* hz */
44
45 #define DURATION_DEF 150 /* ms */
46 #define DURATION_MAX 2000 /* ms */
47 #define DURATION_MIN 50 /* ms */
48
49 #define GAIN_DEF 75
50 #define GAIN_MAX 100
51 #define GAIN_MIN 0
52
53 #define WAVE_POWER 1.25f
54
55 #define DEFAULT_HZ 440
56
57 #define DEFAULT_DEVICE _PATH_DEV "dsp"
58
59 static int frequency = DEFAULT_HZ;
60 static int duration_ms = DURATION_DEF;
61 static int sample_rate = SAMPLE_RATE_DEF;
62 static int gain = GAIN_DEF;
63 static const char *oss_dev = DEFAULT_DEVICE;
64 static bool background;
65
66 /*
67 * wave_function_16
68 *
69 * "phase" should be in the range [0.0f .. 1.0f>
70 * "power" should be in the range <0.0f .. 2.0f>
71 *
72 * The return value is in the range [-1.0f .. 1.0f]
73 */
74 static float
wave_function_16(float phase,float power)75 wave_function_16(float phase, float power)
76 {
77 uint16_t x = phase * (1U << 16);
78 float retval;
79 uint8_t num;
80
81 /* Handle special cases, if any */
82 switch (x) {
83 case 0xffff:
84 case 0x0000:
85 return (1.0f);
86 case 0x3fff:
87 case 0x4000:
88 case 0xBfff:
89 case 0xC000:
90 return (0.0f);
91 case 0x7FFF:
92 case 0x8000:
93 return (-1.0f);
94 default:
95 break;
96 }
97
98 /* Apply Gray coding */
99 for (uint16_t mask = 1U << 15; mask != 1; mask /= 2) {
100 if (x & mask)
101 x ^= (mask - 1);
102 }
103
104 /* Find first set bit */
105 for (num = 0; num != 14; num++) {
106 if (x & (1U << num)) {
107 num++;
108 break;
109 }
110 }
111
112 /* Initialize return value */
113 retval = 0.0;
114
115 /* Compute the rest of the power series */
116 for (; num != 14; num++) {
117 if (x & (1U << num)) {
118 retval = (1.0f - retval) / 2.0f;
119 retval = powf(retval, power);
120 } else {
121 retval = (1.0f + retval) / 2.0f;
122 retval = powf(retval, power);
123 }
124 }
125
126 /* Check if halfway */
127 if (x & (1ULL << 14))
128 retval = -retval;
129
130 return (retval);
131 }
132
133 static void
usage(void)134 usage(void)
135 {
136 fprintf(stderr, "Usage: %s [-Bh] [-D duration_ms] [-F frequency_hz] "
137 "[-d oss_device] [-g gain] [-r sample_rate_hz]\n"
138 "\t" "-B Run in background\n"
139 "\t" "-D <duration in ms, from %d ms to %d ms, default %d ms>\n"
140 "\t" "-F <frequency in Hz, default %d Hz>\n"
141 "\t" "-d <OSS device, default %s>\n"
142 "\t" "-g <gain from %d to %d, default %d>\n"
143 "\t" "-h Show usage\n"
144 "\t" "-r <sample rate in Hz, from %d Hz to %d Hz, default %d Hz>\n",
145 getprogname(),
146 DURATION_MIN, DURATION_MAX, DURATION_DEF,
147 DEFAULT_HZ,
148 DEFAULT_DEVICE,
149 GAIN_MIN, GAIN_MAX, GAIN_DEF,
150 SAMPLE_RATE_MIN, SAMPLE_RATE_MAX, SAMPLE_RATE_DEF);
151 exit(1);
152 }
153
154 int
main(int argc,char ** argv)155 main(int argc, char **argv)
156 {
157 float *buffer;
158 size_t slope;
159 size_t size;
160 size_t off;
161 float a;
162 float d;
163 float p;
164 int c;
165 int f;
166
167 while ((c = getopt(argc, argv, "BF:D:r:g:d:h")) != -1) {
168 switch (c) {
169 case 'F':
170 frequency = strtol(optarg, NULL, 10);
171 break;
172 case 'D':
173 duration_ms = strtol(optarg, NULL, 10);
174 if (duration_ms < DURATION_MIN ||
175 duration_ms > DURATION_MAX)
176 usage();
177 break;
178 case 'r':
179 sample_rate = strtol(optarg, NULL, 10);
180 if (sample_rate < SAMPLE_RATE_MIN ||
181 sample_rate > SAMPLE_RATE_MAX)
182 usage();
183 break;
184 case 'g':
185 gain = strtol(optarg, NULL, 10);
186 if (gain < GAIN_MIN ||
187 gain > GAIN_MAX)
188 usage();
189 break;
190 case 'd':
191 oss_dev = optarg;
192 break;
193 case 'B':
194 background = true;
195 break;
196 default:
197 usage();
198 break;
199 }
200 }
201
202 if (background && daemon(0, 0) != 0)
203 errx(1, "daemon(0,0) failed");
204
205 f = open(oss_dev, O_WRONLY);
206 if (f < 0)
207 err(1, "Failed to open '%s'", oss_dev);
208
209 if (caph_enter() == -1)
210 err(1, "Failed to enter capability mode");
211
212 c = 1; /* mono */
213 if (ioctl(f, SOUND_PCM_WRITE_CHANNELS, &c) != 0)
214 errx(1, "ioctl SOUND_PCM_WRITE_CHANNELS(1) failed");
215
216 c = AFMT_FLOAT;
217 if (ioctl(f, SNDCTL_DSP_SETFMT, &c) != 0)
218 errx(1, "ioctl SNDCTL_DSP_SETFMT(AFMT_FLOAT) failed");
219
220 if (ioctl(f, SNDCTL_DSP_SPEED, &sample_rate) != 0)
221 errx(1, "ioctl SNDCTL_DSP_SPEED(%d) failed", sample_rate);
222
223 c = (2 << 16);
224 while ((1ULL << (c & 63)) < (size_t)(4 * sample_rate / 50))
225 c++;
226 if (ioctl(f, SNDCTL_DSP_SETFRAGMENT, &c))
227 errx(1, "ioctl SNDCTL_DSP_SETFRAGMENT(0x%x) failed", c);
228
229 if (ioctl(f, SNDCTL_DSP_GETODELAY, &c) != 0)
230 errx(1, "ioctl SNDCTL_DSP_GETODELAY failed");
231
232 size = ((sample_rate * duration_ms) + 999) / 1000;
233 buffer = malloc(sizeof(buffer[0]) * size);
234 if (buffer == NULL)
235 errx(1, "out of memory");
236
237 /* compute slope duration in samples */
238 slope = (DURATION_MIN * sample_rate) / 2000;
239
240 /* compute base gain */
241 a = powf(65536.0f, (float)gain / (float)GAIN_MAX) / 65536.0f;
242
243 /* set initial phase and delta */
244 p = 0;
245 d = (float)frequency / (float)sample_rate;
246
247 /* compute wave */
248 for (p = off = 0; off != size; off++, p += d) {
249 float sample;
250
251 p = p - floorf(p);
252 sample = a * wave_function_16(p, WAVE_POWER);
253
254 if (off < slope)
255 sample = sample * off / (float)slope;
256 else if (off > (size - slope))
257 sample = sample * (size - off - 1) / (float)slope;
258
259 buffer[off] = sample;
260 }
261
262 if (write(f, buffer, size * sizeof(buffer[0])) !=
263 (ssize_t)(size * sizeof(buffer[0])))
264 errx(1, "failed writing to DSP device(%s)", oss_dev);
265
266 free(buffer);
267
268 /* wait for data to be written */
269 while (ioctl(f, SNDCTL_DSP_GETODELAY, &c) == 0) {
270 if (c == 0)
271 break;
272 usleep(10000);
273 }
274
275 /* wait for audio to go out */
276 usleep(50000);
277 close(f);
278
279 return (0);
280 }
281