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 <dirent.h>
  13 #include <sys/soundcard.h>
  14 #include <stdbool.h>
  15
  16 #include "para.h"
  17 #include "fd.h"
  18 #include "string.h"
  19 #include "list.h"
  20 #include "sched.h"
  21 #include "ggo.h"
  22 #include "buffer_tree.h"
  23 #include "write.h"
  24 #include "write_common.h"
  25 #include "oss_write.cmdline.h"
  26 #include "error.h"
  27
  28 /** Data specific to the oss writer. */
  29 struct private_oss_write_data {
  30         /** The file handle of the device. */
  31         int fd;
  32         /** Four bytes for stereo streams, two bytes for mono streams. */
  33         int bytes_per_frame;
  34 };
  35
  36 static int get_oss_format(enum sample_format sf)
  37 {
  38         switch (sf) {
  39         case SF_S8: return AFMT_S8;
  40         case SF_U8: return AFMT_U8;
  41         case SF_S16_LE: return AFMT_S16_LE;
  42         case SF_S16_BE: return AFMT_S16_BE;
  43         case SF_U16_LE: return AFMT_U16_LE;
  44         case SF_U16_BE: return AFMT_U16_BE;
  45         default: return AFMT_S16_LE;
  46         }
  47 }
  48
  49 static void oss_pre_select(struct sched *s, struct task *t)
  50 {
  51         struct writer_node *wn = container_of(t, struct writer_node, task);
  52         struct private_oss_write_data *powd = wn->private_data;
  53         int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
  54
  55         if (ret == 0)
  56                 return;
  57         if (ret < 0 || !powd)
  58                 return sched_min_delay(s);
  59         para_fd_set(powd->fd, &s->wfds, &s->max_fileno);
  60 }
  61
  62 static void oss_close(struct writer_node *wn)
  63 {
  64         struct private_oss_write_data *powd = wn->private_data;
  65
  66         if (!powd)
  67                 return;
  68         close(powd->fd);
  69         free(powd);
  70 }
  71
  72 /*
  73  * The Open Sound System Programmer's Guide sayeth:
  74  *
  75  * Set sampling parameters always so that number of channels (mono/stereo) is
  76  * set before selecting sampling rate (speed).  Failing to do this will make
  77  * your program incompatible with cards such as the SoundBlaster Pro which
  78  * supports 44.1 kHz in mono but just 22.05 kHz in stereo. A program which
  79  * selects 44.1 kHz speed and then sets the device to stereo mode will
  80  * incorrectly believe that the device is still in 44.1 kHz mode when actually
  81  * the speed is decreased to 22.05 kHz.
  82  */
  83 static int oss_init(struct writer_node *wn, unsigned sample_rate,
  84                 unsigned channels, int sample_format)
  85 {
  86         int ret, format;
  87         unsigned ch, rate;
  88         struct oss_write_args_info *conf = wn->conf;
  89         struct private_oss_write_data *powd = para_calloc(sizeof(*powd));
  90
  91         wn->private_data = powd;
  92         PARA_INFO_LOG("opening %s\n", conf->device_arg);
  93         ret = para_open(conf->device_arg, O_WRONLY, 0);
  94         if (ret < 0)
  95                 goto err_free;
  96         powd->fd = ret;
  97         ret = mark_fd_nonblocking(powd->fd);
  98         if (ret < 0)
  99                 goto err;
 100         /* set PCM format */
 101         sample_format = format = get_oss_format(sample_format);
 102         ret = ioctl(powd->fd, SNDCTL_DSP_SETFMT, &format);
 103         if (ret < 0) {
 104                 ret = -ERRNO_TO_PARA_ERROR(errno);
 105                 goto err;
 106         }
 107         ret = -E_BAD_SAMPLE_FORMAT;
 108         if (format != sample_format)
 109                 goto err;
 110         /* set number of channels */
 111         ch = channels;
 112         ret = ioctl(powd->fd, SNDCTL_DSP_CHANNELS, &ch);
 113         if (ret < 0) {
 114                 ret = -ERRNO_TO_PARA_ERROR(errno);
 115                 goto err;
 116         }
 117         ret = -E_BAD_CHANNEL_COUNT;
 118         if (ch != channels)
 119                 goto err;
 120         if (format == SF_U8 || format == SF_S8)
 121                 powd->bytes_per_frame = ch;
 122         else
 123                 powd->bytes_per_frame = ch * 2;
 124
 125         /*
 126          * Set sampling rate
 127          *
 128          * If we request a higher sampling rate than is supported by the
 129          * device, the the highest possible speed is automatically used. The
 130          * value actually used is returned as the new value of the argument.
 131          */
 132         rate = sample_rate;
 133         ret = ioctl(powd->fd, SNDCTL_DSP_SPEED, &rate);
 134         if (ret < 0) {
 135                 ret = -ERRNO_TO_PARA_ERROR(errno);
 136                 goto err;
 137         }
 138         if (rate != sample_rate) {
 139                 unsigned min = PARA_MIN(rate, sample_rate),
 140                         max = PARA_MAX(rate, sample_rate);
 141                 /*
 142                  * Check whether the returned sample rate differs significantly
 143                  * from the requested one.
 144                  */
 145                 ret = -E_BAD_SAMPLERATE;
 146                 if (100 * max > 110 * min) /* more than 10% deviation */
 147                         goto err;
 148                 PARA_NOTICE_LOG("using %dHz rather than %dHz\n", rate,
 149                         sample_rate);
 150         }
 151         wn->min_iqs = powd->bytes_per_frame;
 152         return 1;
 153 err:
 154         close(powd->fd);
 155 err_free:
 156         free(powd);
 157         return ret;
 158 }
 159
 160 static void oss_post_select(__a_unused struct sched *s,
 161                 struct task *t)
 162 {
 163         struct writer_node *wn = container_of(t, struct writer_node, task);
 164         struct private_oss_write_data *powd = wn->private_data;
 165         struct btr_node *btrn = wn->btrn;
 166         size_t frames, bytes;
 167         int ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
 168         char *data;
 169
 170         if (ret < 0)
 171                 goto out;
 172         if (ret == 0)
 173                 return;
 174         if (!powd) {
 175                 int32_t rate, ch, format;
 176                 get_btr_sample_rate(btrn, &rate);
 177                 get_btr_channels(btrn, &ch);
 178                 get_btr_sample_format(btrn, &format);
 179                 ret = oss_init(wn, rate, ch, format);
 180                 if (ret < 0)
 181                         goto out;
 182                 return;
 183         }
 184         btr_merge(btrn, wn->min_iqs);
 185         bytes = btr_next_buffer(btrn, &data);
 186         frames = bytes / powd->bytes_per_frame;
 187         if (!frames) { /* eof and less than a single frame available */
 188                 ret = -E_OSS_EOF;
 189                 goto out;
 190         }
 191         ret = 0;
 192         if (!FD_ISSET(powd->fd, &s->wfds))
 193                 goto out;
 194         ret = write_nonblock(powd->fd, data, frames * powd->bytes_per_frame);
 195         if (ret < 0)
 196                 goto out;
 197         btr_consume(btrn, ret);
 198         ret = 0;
 199 out:
 200         t->error = ret;
 201         if (ret < 0)
 202                 btr_remove_node(btrn);
 203 }
 204
 205 __malloc static void *oss_parse_config_or_die(const char *options)
 206 {
 207         struct oss_write_args_info *conf = para_calloc(sizeof(*conf));
 208
 209         /* exits on errors */
 210         oss_cmdline_parser_string(options, conf, "oss_write");
 211         return conf;
 212 }
 213
 214 static void oss_free_config(void *conf)
 215 {
 216         oss_cmdline_parser_free(conf);
 217 }
 218
 219 /**
 220  * The init function of the oss writer.
 221  *
 222  * \param w Pointer to the writer to initialize.
 223  *
 224  * \sa struct writer.
 225  */
 226 void oss_write_init(struct writer *w)
 227 {
 228         struct oss_write_args_info dummy;
 229
 230         oss_cmdline_parser_init(&dummy);
 231         w->close = oss_close;
 232         w->pre_select = oss_pre_select;
 233         w->post_select = oss_post_select;
 234         w->parse_config_or_die = oss_parse_config_or_die;
 235         w->free_config = oss_free_config;
 236         w->shutdown = NULL;
 237         w->help = (struct ggo_help) {
 238                 .short_help = oss_write_args_info_help,
 239                 .detailed_help = oss_write_args_info_detailed_help
 240         };
 241         oss_cmdline_parser_free(&dummy);
 242 }