oss_write.c

   1 /*
   2  * Copyright (C) 2009-2011 Andre Noll <maan@systemlinux.org>
   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 #include <stdbool.h>
  14
  15 #include "para.h"
  16 #include "fd.h"
  17 #include "string.h"
  18 #include "list.h"
  19 #include "sched.h"
  20 #include "ggo.h"
  21 #include "buffer_tree.h"
  22 #include "write.h"
  23 #include "write_common.h"
  24 #include "oss_write.cmdline.h"
  25 #include "error.h"
  26
  27 /** Data specific to the oss writer. */
  28 struct private_oss_write_data {
  29         /** The file handle of the device. */
  30         int fd;
  31         /** Four bytes for stereo streams, two bytes for mono streams. */
  32         int bytes_per_frame;
  33 };
  34
  35 static int get_oss_format(enum sample_format sf)
  36 {
  37         switch (sf) {
  38         case SF_S8: return AFMT_S8;
  39         case SF_U8: return AFMT_U8;
  40         case SF_S16_LE: return AFMT_S16_LE;
  41         case SF_S16_BE: return AFMT_S16_BE;
  42         case SF_U16_LE: return AFMT_U16_LE;
  43         case SF_U16_BE: return AFMT_U16_BE;
  44         default: return AFMT_S16_LE;
  45         }
  46 }
  47
  48 static void oss_pre_select(struct sched *s, struct task *t)
  49 {
  50         struct writer_node *wn = container_of(t, struct writer_node, task);
  51         struct private_oss_write_data *powd = wn->private_data;
  52         int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
  53
  54         if (ret == 0)
  55                 return;
  56         if (ret < 0 || !powd)
  57                 return sched_min_delay(s);
  58         para_fd_set(powd->fd, &s->wfds, &s->max_fileno);
  59 }
  60
  61 static void oss_close(struct writer_node *wn)
  62 {
  63         struct private_oss_write_data *powd = wn->private_data;
  64
  65         if (!powd)
  66                 return;
  67         close(powd->fd);
  68         free(powd);
  69 }
  70
  71 /*
  72  * The Open Sound System Programmer's Guide sayeth:
  73  *
  74  * Set sampling parameters always so that number of channels (mono/stereo) is
  75  * set before selecting sampling rate (speed).  Failing to do this will make
  76  * your program incompatible with cards such as the SoundBlaster Pro which
  77  * supports 44.1 kHz in mono but just 22.05 kHz in stereo. A program which
  78  * selects 44.1 kHz speed and then sets the device to stereo mode will
  79  * incorrectly believe that the device is still in 44.1 kHz mode when actually
  80  * the speed is decreased to 22.05 kHz.
  81  */
  82 static int oss_init(struct writer_node *wn, unsigned sample_rate,
  83                 unsigned channels, int sample_format)
  84 {
  85         int ret, format;
  86         unsigned ch, rate;
  87         struct oss_write_args_info *conf = wn->conf;
  88         struct private_oss_write_data *powd = para_calloc(sizeof(*powd));
  89
  90         PARA_INFO_LOG("opening %s\n", conf->device_arg);
  91         ret = para_open(conf->device_arg, O_WRONLY, 0);
  92         if (ret < 0)
  93                 goto err_free;
  94         powd->fd = ret;
  95         ret = mark_fd_nonblocking(powd->fd);
  96         if (ret < 0)
  97                 goto err;
  98         /* set PCM format */
  99         sample_format = format = get_oss_format(sample_format);
 100         ret = ioctl(powd->fd, SNDCTL_DSP_SETFMT, &format);
 101         if (ret < 0) {
 102                 ret = -ERRNO_TO_PARA_ERROR(errno);
 103                 goto err;
 104         }
 105         ret = -E_BAD_SAMPLE_FORMAT;
 106         if (format != sample_format)
 107                 goto err;
 108         /* set number of channels */
 109         ch = channels;
 110         ret = ioctl(powd->fd, SNDCTL_DSP_CHANNELS, &ch);
 111         if (ret < 0) {
 112                 ret = -ERRNO_TO_PARA_ERROR(errno);
 113                 goto err;
 114         }
 115         ret = -E_BAD_CHANNEL_COUNT;
 116         if (ch != channels)
 117                 goto err;
 118         if (format == SF_U8 || format == SF_S8)
 119                 powd->bytes_per_frame = ch;
 120         else
 121                 powd->bytes_per_frame = ch * 2;
 122
 123         /*
 124          * Set sampling rate
 125          *
 126          * If we request a higher sampling rate than is supported by the
 127          * device, the the highest possible speed is automatically used. The
 128          * value actually used is returned as the new value of the argument.
 129          */
 130         rate = sample_rate;
 131         ret = ioctl(powd->fd, SNDCTL_DSP_SPEED, &rate);
 132         if (ret < 0) {
 133                 ret = -ERRNO_TO_PARA_ERROR(errno);
 134                 goto err;
 135         }
 136         if (rate != sample_rate) {
 137                 unsigned min = PARA_MIN(rate, sample_rate),
 138                         max = PARA_MAX(rate, sample_rate);
 139                 /*
 140                  * Check whether the returned sample rate differs significantly
 141                  * from the requested one.
 142                  */
 143                 ret = -E_BAD_SAMPLERATE;
 144                 if (100 * max > 110 * min) /* more than 10% deviation */
 145                         goto err;
 146                 PARA_NOTICE_LOG("using %dHz rather than %dHz\n", rate,
 147                         sample_rate);
 148         }
 149         wn->min_iqs = powd->bytes_per_frame;
 150         wn->private_data = powd;
 151         return 1;
 152 err:
 153         close(powd->fd);
 154 err_free:
 155         free(powd);
 156         return ret;
 157 }
 158
 159 static void oss_post_select(__a_unused struct sched *s,
 160                 struct task *t)
 161 {
 162         struct writer_node *wn = container_of(t, struct writer_node, task);
 163         struct private_oss_write_data *powd = wn->private_data;
 164         struct btr_node *btrn = wn->btrn;
 165         size_t frames, bytes;
 166         int ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
 167         char *data;
 168
 169         if (ret < 0)
 170                 goto out;
 171         if (ret == 0)
 172                 return;
 173         if (!powd) {
 174                 int32_t rate, ch, format;
 175                 get_btr_sample_rate(btrn, &rate);
 176                 get_btr_channels(btrn, &ch);
 177                 get_btr_sample_format(btrn, &format);
 178                 ret = oss_init(wn, rate, ch, format);
 179                 if (ret < 0)
 180                         goto out;
 181                 return;
 182         }
 183         btr_merge(btrn, wn->min_iqs);
 184         bytes = btr_next_buffer(btrn, &data);
 185         frames = bytes / powd->bytes_per_frame;
 186         if (!frames) { /* eof and less than a single frame available */
 187                 ret = -E_WRITE_COMMON_EOF;
 188                 goto out;
 189         }
 190         ret = 0;
 191         if (!FD_ISSET(powd->fd, &s->wfds))
 192                 goto out;
 193         ret = write_nonblock(powd->fd, data, frames * powd->bytes_per_frame);
 194         if (ret < 0)
 195                 goto out;
 196         btr_consume(btrn, ret);
 197         ret = 0;
 198 out:
 199         t->error = ret;
 200         if (ret < 0)
 201                 btr_remove_node(btrn);
 202 }
 203
 204 __malloc static void *oss_parse_config_or_die(const char *options)
 205 {
 206         struct oss_write_args_info *conf = para_calloc(sizeof(*conf));
 207
 208         /* exits on errors */
 209         oss_cmdline_parser_string(options, conf, "oss_write");
 210         return conf;
 211 }
 212
 213 static void oss_free_config(void *conf)
 214 {
 215         oss_cmdline_parser_free(conf);
 216 }
 217
 218 /**
 219  * The init function of the oss writer.
 220  *
 221  * \param w Pointer to the writer to initialize.
 222  *
 223  * \sa struct writer.
 224  */
 225 void oss_write_init(struct writer *w)
 226 {
 227         struct oss_write_args_info dummy;
 228
 229         oss_cmdline_parser_init(&dummy);
 230         w->close = oss_close;
 231         w->pre_select = oss_pre_select;
 232         w->post_select = oss_post_select;
 233         w->parse_config_or_die = oss_parse_config_or_die;
 234         w->free_config = oss_free_config;
 235         w->shutdown = NULL;
 236         w->help = (struct ggo_help) {
 237                 .short_help = oss_write_args_info_help,
 238                 .detailed_help = oss_write_args_info_detailed_help
 239         };
 240         oss_cmdline_parser_free(&dummy);
 241 }