oss_write.c

   1 /*
   2  * Copyright (C) 2009-2014 Andre Noll <maan@tuebingen.mpg.de>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file oss_write.c Paraslash's oss output plugin. */
   8
   9 #include <regex.h>
  10 #include <sys/ioctl.h>
  11 #include <fcntl.h>
  12 #include <sys/soundcard.h>
  13
  14 #include "para.h"
  15 #include "fd.h"
  16 #include "string.h"
  17 #include "list.h"
  18 #include "sched.h"
  19 #include "ggo.h"
  20 #include "buffer_tree.h"
  21 #include "write.h"
  22 #include "write_common.h"
  23 #include "oss_write.cmdline.h"
  24 #include "error.h"
  25
  26 /** Data specific to the oss writer. */
  27 struct private_oss_write_data {
  28         /** The file handle of the device. */
  29         int fd;
  30         /** Four bytes for stereo streams, two bytes for mono streams. */
  31         int bytes_per_frame;
  32 };
  33
  34 /*
  35  * We keep one bit of static storage to make sure only one instance of the oss
  36  * writer is running at any given time.
  37  */
  38 static bool sound_device_busy;
  39
  40 static bool sound_device_is_busy(void)
  41 {
  42         return sound_device_busy;
  43 }
  44
  45 static void set_sound_device_busy(void)
  46 {
  47         assert(!sound_device_busy);
  48         sound_device_busy = true;
  49 }
  50
  51 static void set_sound_device_idle(void)
  52 {
  53         assert(sound_device_busy);
  54         sound_device_busy = false;
  55 }
  56
  57 static int get_oss_format(enum sample_format sf)
  58 {
  59         switch (sf) {
  60         case SF_S8: return AFMT_S8;
  61         case SF_U8: return AFMT_U8;
  62         case SF_S16_LE: return AFMT_S16_LE;
  63         case SF_S16_BE: return AFMT_S16_BE;
  64         case SF_U16_LE: return AFMT_U16_LE;
  65         case SF_U16_BE: return AFMT_U16_BE;
  66         default: return AFMT_S16_LE;
  67         }
  68 }
  69
  70 static void oss_pre_select(struct sched *s, void *context)
  71 {
  72         struct writer_node *wn = context;
  73         struct private_oss_write_data *powd = wn->private_data;
  74         int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
  75
  76         if (ret == 0 || (sound_device_is_busy() && !powd))
  77                 return;
  78         if (ret < 0 || !powd)
  79                 return sched_min_delay(s);
  80         para_fd_set(powd->fd, &s->wfds, &s->max_fileno);
  81 }
  82
  83 static void oss_close(struct writer_node *wn)
  84 {
  85         struct private_oss_write_data *powd = wn->private_data;
  86
  87         if (!powd)
  88                 return;
  89         close(powd->fd);
  90         free(powd);
  91         set_sound_device_idle();
  92 }
  93
  94 /*
  95  * The Open Sound System Programmer's Guide sayeth:
  96  *
  97  * Set sampling parameters always so that number of channels (mono/stereo) is
  98  * set before selecting sampling rate (speed).  Failing to do this will make
  99  * your program incompatible with cards such as the SoundBlaster Pro which
 100  * supports 44.1 kHz in mono but just 22.05 kHz in stereo. A program which
 101  * selects 44.1 kHz speed and then sets the device to stereo mode will
 102  * incorrectly believe that the device is still in 44.1 kHz mode when actually
 103  * the speed is decreased to 22.05 kHz.
 104  */
 105 static int oss_init(struct writer_node *wn, unsigned sample_rate,
 106                 unsigned channels, int sample_format)
 107 {
 108         int ret, format;
 109         unsigned ch, rate;
 110         struct oss_write_args_info *conf = wn->conf;
 111         struct private_oss_write_data *powd = para_calloc(sizeof(*powd));
 112
 113         PARA_INFO_LOG("opening %s\n", conf->device_arg);
 114         ret = para_open(conf->device_arg, O_WRONLY, 0);
 115         if (ret < 0)
 116                 goto err_free;
 117         powd->fd = ret;
 118         ret = mark_fd_nonblocking(powd->fd);
 119         if (ret < 0)
 120                 goto err;
 121         /* set PCM format */
 122         sample_format = format = get_oss_format(sample_format);
 123         ret = ioctl(powd->fd, SNDCTL_DSP_SETFMT, &format);
 124         if (ret < 0) {
 125                 ret = -ERRNO_TO_PARA_ERROR(errno);
 126                 goto err;
 127         }
 128         ret = -E_BAD_SAMPLE_FORMAT;
 129         if (format != sample_format)
 130                 goto err;
 131         /* set number of channels */
 132         ch = channels;
 133         ret = ioctl(powd->fd, SNDCTL_DSP_CHANNELS, &ch);
 134         if (ret < 0) {
 135                 ret = -ERRNO_TO_PARA_ERROR(errno);
 136                 goto err;
 137         }
 138         ret = -E_BAD_CHANNEL_COUNT;
 139         if (ch != channels)
 140                 goto err;
 141         if (format == SF_U8 || format == SF_S8)
 142                 powd->bytes_per_frame = ch;
 143         else
 144                 powd->bytes_per_frame = ch * 2;
 145
 146         /*
 147          * Set sampling rate
 148          *
 149          * If we request a higher sampling rate than is supported by the
 150          * device, the highest possible speed is automatically used. The
 151          * value actually used is returned as the new value of the argument.
 152          */
 153         rate = sample_rate;
 154         ret = ioctl(powd->fd, SNDCTL_DSP_SPEED, &rate);
 155         if (ret < 0) {
 156                 ret = -ERRNO_TO_PARA_ERROR(errno);
 157                 goto err;
 158         }
 159         if (rate != sample_rate) {
 160                 unsigned min = PARA_MIN(rate, sample_rate),
 161                         max = PARA_MAX(rate, sample_rate);
 162                 /*
 163                  * Check whether the returned sample rate differs significantly
 164                  * from the requested one.
 165                  */
 166                 ret = -E_BAD_SAMPLERATE;
 167                 if (100 * max > 110 * min) /* more than 10% deviation */
 168                         goto err;
 169                 PARA_NOTICE_LOG("using %dHz rather than %dHz\n", rate,
 170                         sample_rate);
 171         }
 172         wn->min_iqs = powd->bytes_per_frame;
 173         wn->private_data = powd;
 174         return 1;
 175 err:
 176         close(powd->fd);
 177 err_free:
 178         free(powd);
 179         PARA_ERROR_LOG("failed to init %s: %s\n", conf->device_arg,
 180                 para_strerror(-ret));
 181         return ret;
 182 }
 183
 184 static int oss_post_select(__a_unused struct sched *s, void *context)
 185 {
 186         struct writer_node *wn = context;
 187         struct private_oss_write_data *powd = wn->private_data;
 188         struct btr_node *btrn = wn->btrn;
 189         size_t frames, bytes;
 190         int ret;
 191         char *data;
 192         audio_buf_info abi;
 193
 194         ret = task_get_notification(wn->task);
 195         if (ret < 0)
 196                 goto out;
 197         ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
 198         if (ret <= 0)
 199                 goto out;
 200         if (!powd) {
 201                 int32_t rate, ch, format;
 202
 203                 if (sound_device_is_busy())
 204                         return 0;
 205                 get_btr_sample_rate(btrn, &rate);
 206                 get_btr_channels(btrn, &ch);
 207                 get_btr_sample_format(btrn, &format);
 208                 ret = oss_init(wn, rate, ch, format);
 209                 if (ret < 0)
 210                         goto out;
 211                 set_sound_device_busy();
 212                 return 0;
 213         }
 214         btr_merge(btrn, wn->min_iqs);
 215         bytes = btr_next_buffer(btrn, &data);
 216         frames = bytes / powd->bytes_per_frame;
 217         if (!frames) { /* eof and less than a single frame available */
 218                 ret = -E_WRITE_COMMON_EOF;
 219                 goto out;
 220         }
 221         ret = 0;
 222         if (!FD_ISSET(powd->fd, &s->wfds))
 223                 goto out;
 224         /* get maximal number of bytes that can be written */
 225         ret = ioctl(powd->fd, SNDCTL_DSP_GETOSPACE, &abi);
 226         if (ret >= 0) {
 227                 size_t max_frames = abi.bytes / powd->bytes_per_frame;
 228                 if (max_frames == 0)
 229                         goto out;
 230                 /* cap number of frames to avoid sound artefacts */
 231                 frames = PARA_MIN(frames, max_frames);
 232         }
 233         ret = xwrite(powd->fd, data, frames * powd->bytes_per_frame);
 234         if (ret < 0)
 235                 goto out;
 236         btr_consume(btrn, ret);
 237         ret = 0;
 238 out:
 239         if (ret < 0)
 240                 btr_remove_node(&wn->btrn);
 241         return ret;
 242 }
 243
 244 __malloc static void *oss_parse_config_or_die(int argc, char **argv)
 245 {
 246         struct oss_write_args_info *conf = para_calloc(sizeof(*conf));
 247
 248         /* exits on errors */
 249         oss_write_cmdline_parser(argc, argv, conf);
 250         return conf;
 251 }
 252
 253 static void oss_free_config(void *conf)
 254 {
 255         oss_write_cmdline_parser_free(conf);
 256 }
 257
 258 /**
 259  * The init function of the oss writer.
 260  *
 261  * \param w Pointer to the writer to initialize.
 262  *
 263  * \sa struct writer.
 264  */
 265 void oss_write_init(struct writer *w)
 266 {
 267         struct oss_write_args_info dummy;
 268
 269         oss_write_cmdline_parser_init(&dummy);
 270         w->close = oss_close;
 271         w->pre_select = oss_pre_select;
 272         w->post_select = oss_post_select;
 273         w->parse_config_or_die = oss_parse_config_or_die;
 274         w->free_config = oss_free_config;
 275         w->help = (struct ggo_help)DEFINE_GGO_HELP(oss_write);
 276         oss_write_cmdline_parser_free(&dummy);
 277 }