oss_write.c

   1 /*
   2  * Copyright (C) 2009-2010 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 /** Always use 16 bit little endian. */
  29 #define FORMAT AFMT_S16_LE
  30
  31 /** Data specific to the oss writer. */
  32 struct private_oss_write_data {
  33         /** The file handle of the device. */
  34         int fd;
  35         /** Four bytes for stereo streams, two bytes for mono streams. */
  36         int bytes_per_frame;
  37 };
  38
  39 static void oss_pre_select(struct sched *s, struct task *t)
  40 {
  41         struct writer_node *wn = container_of(t, struct writer_node, task);
  42         struct private_oss_write_data *powd = wn->private_data;
  43         int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
  44
  45         t->error = 0;
  46         if (ret < 0)
  47                 sched_min_delay(s);
  48         else if (ret > 0)
  49                 para_fd_set(powd->fd, &s->wfds, &s->max_fileno);
  50 }
  51
  52 static void oss_close(struct writer_node *wn)
  53 {
  54         struct private_oss_write_data *powd = wn->private_data;
  55
  56         if (powd->fd >= 0)
  57                 close(powd->fd);
  58         free(powd);
  59 }
  60
  61 /*
  62  * The Open Sound System Programmer's Guide sayeth:
  63  *
  64  * Set sampling parameters always so that number of channels (mono/stereo) is
  65  * set before selecting sampling rate (speed).  Failing to do this will make
  66  * your program incompatible with cards such as the SoundBlaster Pro which
  67  * supports 44.1 kHz in mono but just 22.05 kHz in stereo. A program which
  68  * selects 44.1 kHz speed and then sets the device to stereo mode will
  69  * incorrectly believe that the device is still in 44.1 kHz mode when actually
  70  * the speed is decreased to 22.05 kHz.
  71  */
  72 static int oss_init(struct writer_node *wn, unsigned sample_rate, unsigned channels)
  73 {
  74         int ret, format = FORMAT;
  75         unsigned ch, rate;
  76         struct oss_write_args_info *conf = wn->conf;
  77         struct private_oss_write_data *powd = wn->private_data;
  78
  79         PARA_INFO_LOG("opening %s\n", conf->device_arg);
  80         ret = para_open(conf->device_arg, O_WRONLY, 0);
  81         if (ret < 0)
  82                 return ret;
  83         powd->fd = ret;
  84         ret = mark_fd_nonblocking(powd->fd);
  85         if (ret < 0)
  86                 goto err;
  87         /* set PCM format */
  88         ret = ioctl(powd->fd, SNDCTL_DSP_SETFMT, &format);
  89         if (ret < 0) {
  90                 ret = -ERRNO_TO_PARA_ERROR(errno);
  91                 goto err;
  92         }
  93         ret = -E_BAD_SAMPLE_FORMAT;
  94         if (format != FORMAT)
  95                 goto err;
  96         /* set number of channels */
  97         ret = -E_BAD_CHANNEL_COUNT;
  98         if (channels == 0)
  99                 goto err;
 100         ch = channels;
 101         ret = ioctl(powd->fd, SNDCTL_DSP_CHANNELS, &ch);
 102         if (ret < 0) {
 103                 ret = -ERRNO_TO_PARA_ERROR(errno);
 104                 goto err;
 105         }
 106         ret = -E_BAD_CHANNEL_COUNT;
 107         if (ch != channels)
 108                 goto err;
 109         powd->bytes_per_frame = ch * 2;
 110
 111         /*
 112          * Set sampling rate
 113          *
 114          * If we request a higher sampling rate than is supported by the
 115          * device, the the highest possible speed is automatically used. The
 116          * value actually used is returned as the new value of the argument.
 117          */
 118         rate = sample_rate;
 119         ret = ioctl(powd->fd, SNDCTL_DSP_SPEED, &rate);
 120         if (ret < 0) {
 121                 ret = -ERRNO_TO_PARA_ERROR(errno);
 122                 goto err;
 123         }
 124         if (rate != sample_rate) {
 125                 unsigned min = PARA_MIN(rate, sample_rate),
 126                         max = PARA_MAX(rate, sample_rate);
 127                 /*
 128                  * Check whether the returned sample rate differs significantly
 129                  * from the requested one.
 130                  */
 131                 ret = -E_BAD_SAMPLERATE;
 132                 if (100 * max > 110 * min) /* more than 10% deviation */
 133                         goto err;
 134                 PARA_NOTICE_LOG("using %dHz rather than %dHz\n", rate,
 135                         sample_rate);
 136         }
 137         wn->min_iqs = powd->bytes_per_frame;
 138         return 1;
 139 err:
 140         close(powd->fd);
 141         powd->fd = -1;
 142         return ret;
 143 }
 144
 145 static void oss_post_select(__a_unused struct sched *s,
 146                 struct task *t)
 147 {
 148         struct writer_node *wn = container_of(t, struct writer_node, task);
 149         struct oss_write_args_info *conf = wn->conf;
 150         struct private_oss_write_data *powd = wn->private_data;
 151         struct btr_node *btrn = wn->btrn;
 152         size_t frames, bytes;
 153         int ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
 154         char *data;
 155
 156         if (ret < 0)
 157                 goto out;
 158         if (ret == 0)
 159                 return;
 160         if (powd->fd < 0) {
 161                 int32_t rate, ch;
 162                 ret = -1;
 163                 if (!conf->sample_rate_given) /* config option trumps btr_exec */
 164                         ret = get_btr_sample_rate(wn->btrn, &rate);
 165                 if (ret < 0)
 166                         rate = conf->sample_rate_arg;
 167                 ret = -1;
 168                 if (!conf->channels_given)
 169                         ret = get_btr_channels(wn->btrn, &ch);
 170                 if (ret < 0)
 171                         ch = conf->channels_arg;
 172                 ret = oss_init(wn, rate, ch);
 173                 if (ret < 0)
 174                         goto out;
 175                 return;
 176         }
 177         btr_merge(btrn, wn->min_iqs);
 178         bytes = btr_next_buffer(btrn, &data);
 179         frames = bytes / powd->bytes_per_frame;
 180         if (!frames) { /* eof and less than a single frame available */
 181                 ret = -E_OSS_EOF;
 182                 goto out;
 183         }
 184         ret = 0;
 185         if (!FD_ISSET(powd->fd, &s->wfds))
 186                 goto out;
 187         ret = write_nonblock(powd->fd, data, frames * powd->bytes_per_frame);
 188         if (ret < 0)
 189                 goto out;
 190         btr_consume(btrn, ret);
 191         ret = 0;
 192 out:
 193         t->error = ret;
 194         if (ret < 0)
 195                 btr_remove_node(btrn);
 196 }
 197
 198 static int oss_open(struct writer_node *wn)
 199 {
 200         struct private_oss_write_data *powd;
 201
 202         powd = para_calloc(sizeof(*powd));
 203         wn->private_data = powd;
 204         powd->fd = -1;
 205         return 1;
 206 }
 207
 208 __malloc static void *oss_parse_config(const char *options)
 209 {
 210         int ret;
 211         struct oss_write_args_info *conf = para_calloc(sizeof(*conf));
 212
 213         ret = oss_cmdline_parser_string(options, conf, "oss_write");
 214         if (ret)
 215                 goto err_out;
 216         return conf;
 217 err_out:
 218         free(conf);
 219         return NULL;
 220 }
 221
 222 static void oss_free_config(void *conf)
 223 {
 224         oss_cmdline_parser_free(conf);
 225 }
 226
 227 /**
 228  * The init function of the oss writer.
 229  *
 230  * \param w Pointer to the writer to initialize.
 231  *
 232  * \sa struct writer.
 233  */
 234 void oss_write_init(struct writer *w)
 235 {
 236         struct oss_write_args_info dummy;
 237
 238         oss_cmdline_parser_init(&dummy);
 239         w->open = oss_open;
 240         w->close = oss_close;
 241         w->pre_select = oss_pre_select;
 242         w->post_select = oss_post_select;
 243         w->parse_config = oss_parse_config;
 244         w->free_config = oss_free_config;
 245         w->shutdown = NULL;
 246         w->help = (struct ggo_help) {
 247                 .short_help = oss_write_args_info_help,
 248                 .detailed_help = oss_write_args_info_detailed_help
 249         };
 250         oss_cmdline_parser_free(&dummy);
 251 }