oss_write.c

   1 /*
   2  * Copyright (C) 2009 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         /**
  36          * The samplerate given by command line option or the decoder
  37          * of the writer node group.
  38          */
  39         int samplerate;
  40         /**
  41          * The number of channels, given by command line option or the
  42          * decoder of the writer node group.
  43          */
  44         int channels;
  45         /** Four bytes for stereo streams, two bytes for mono streams. */
  46         int bytes_per_frame;
  47 };
  48
  49 static void oss_pre_select_btr(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         t->error = 0;
  56         if (ret < 0)
  57                 goto min_delay;
  58         if (ret == 0)
  59                 return;
  60         if (!powd)
  61                 goto min_delay;
  62         para_fd_set(powd->fd, &s->wfds, &s->max_fileno);
  63         return;
  64 min_delay:
  65         s->timeout.tv_sec = 0;
  66         s->timeout.tv_usec = 1;
  67 }
  68
  69 static void oss_close(struct writer_node *wn)
  70 {
  71         struct private_oss_write_data *powd = wn->private_data;
  72
  73         close(powd->fd);
  74         oss_cmdline_parser_free(wn->conf);
  75         free(powd);
  76 }
  77
  78 /*
  79  * The Open Sound System Programmer's Guide sayeth:
  80  *
  81  * Set sampling parameters always so that number of channels (mono/stereo) is
  82  * set before selecting sampling rate (speed).  Failing to do this will make
  83  * your program incompatible with cards such as the SoundBlaster Pro which
  84  * supports 44.1 kHz in mono but just 22.05 kHz in stereo. A program which
  85  * selects 44.1 kHz speed and then sets the device to stereo mode will
  86  * incorrectly believe that the device is still in 44.1 kHz mode when actually
  87  * the speed is decreased to 22.05 kHz.
  88  */
  89 static int oss_init(struct writer_node *wn, unsigned samplerate, unsigned channels)
  90 {
  91         int ret, format = FORMAT, ch, rate;
  92         struct oss_write_args_info *conf = wn->conf;
  93         struct private_oss_write_data *powd = wn->private_data;
  94
  95         PARA_INFO_LOG("opening %s\n", conf->device_arg);
  96         ret = para_open(conf->device_arg, O_WRONLY, 0);
  97         if (ret < 0)
  98                 return ret;
  99         powd->fd = ret;
 100         ret = mark_fd_nonblocking(powd->fd);
 101         if (ret < 0)
 102                 goto err;
 103         /* set PCM format */
 104         ret = ioctl(powd->fd, SNDCTL_DSP_SETFMT, &format);
 105         if (ret < 0) {
 106                 ret = -ERRNO_TO_PARA_ERROR(errno);
 107                 goto err;
 108         }
 109         ret = -E_BAD_SAMPLE_FORMAT;
 110         if (format != FORMAT)
 111                 goto err;
 112         /* set number of channels */
 113         if (!conf->channels_given && channels != 0)
 114                 ch = channels;
 115         else
 116                 ch = conf->channels_arg;
 117         ret = -E_BAD_CHANNEL_COUNT;
 118         if (ch == 0)
 119                 goto err;
 120         powd->channels = ch;
 121         ret = ioctl(powd->fd, SNDCTL_DSP_CHANNELS, &ch);
 122         if (ret < 0) {
 123                 ret = -ERRNO_TO_PARA_ERROR(errno);
 124                 goto err;
 125         }
 126         if (powd->channels != ch)
 127                 goto err;
 128         powd->bytes_per_frame = ch * 2;
 129
 130         /*
 131          * Set sampling rate
 132          *
 133          * If we request a higher sampling rate than is supported by the
 134          * device, the the highest possible speed is automatically used. The
 135          * value actually used is returned as the new value of the argument.
 136          */
 137         if (!conf->samplerate_given && samplerate != 0)
 138                 rate = samplerate;
 139         else
 140                 rate = conf->samplerate_arg;
 141         powd->samplerate = rate;
 142         ret = ioctl(powd->fd, SNDCTL_DSP_SPEED, &rate);
 143         if (ret < 0) {
 144                 ret = -ERRNO_TO_PARA_ERROR(errno);
 145                 goto err;
 146         }
 147         if (rate != powd->samplerate) {
 148                 int min = PARA_MIN(rate, powd->samplerate),
 149                         max = PARA_MAX(rate, powd->samplerate);
 150                 /*
 151                  * Check whether the returned sample rate differs significantly
 152                  * from the requested one.
 153                  */
 154                 ret = -E_BAD_SAMPLERATE;
 155                 if (100 * max > 110 * min) /* more than 10% deviation */
 156                         goto err;
 157                 PARA_NOTICE_LOG("using %dHz rather than %dHz\n", rate,
 158                         powd->samplerate);
 159         }
 160         wn->min_iqs = powd->bytes_per_frame;
 161         return 1;
 162 err:
 163         close(powd->fd);
 164         free(powd);
 165         return ret;
 166 }
 167
 168 static void oss_post_select_btr(__a_unused struct sched *s,
 169                 struct task *t)
 170 {
 171         struct writer_node *wn = container_of(t, struct writer_node, task);
 172         struct oss_write_args_info *conf = wn->conf;
 173         struct private_oss_write_data *powd = wn->private_data;
 174         struct btr_node *btrn = wn->btrn;
 175         size_t frames, bytes;
 176         int ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
 177         char *data;
 178
 179         if (ret < 0)
 180                 goto out;
 181         if (ret == 0)
 182                 return;
 183         if (powd->fd < 0) {
 184                 int32_t rate, ch;
 185                 ret = -1;
 186                 if (!conf->samplerate_given) /* config option trumps btr_exec */
 187                         ret = get_btr_samplerate(wn->btrn, &rate);
 188                 if (ret < 0)
 189                         rate = conf->samplerate_arg;
 190                 ret = -1;
 191                 if (!conf->channels_given)
 192                         ret = get_btr_channels(wn->btrn, &ch);
 193                 if (ret < 0)
 194                         ch = conf->channels_arg;
 195                 ret = oss_init(wn, rate, ch);
 196                 if (ret < 0)
 197                         goto out;
 198                 return;
 199         }
 200         bytes = btr_next_buffer(btrn, &data);
 201         frames = bytes / powd->bytes_per_frame;
 202         if (!frames) { /* eof and less than a single frame available */
 203                 ret = -E_OSS_EOF;
 204                 goto out;
 205         }
 206         ret = 0;
 207         if (!FD_ISSET(powd->fd, &s->wfds))
 208                 goto out;
 209         ret = write_nonblock(powd->fd, data, frames * powd->bytes_per_frame, 0);
 210         if (ret < 0)
 211                 goto out;
 212         btr_consume(btrn, ret);
 213         ret = 0;
 214 out:
 215         t->error = ret;
 216         if (ret < 0)
 217                 btr_remove_node(btrn);
 218 }
 219
 220 static int oss_open(struct writer_node *wn)
 221 {
 222         struct writer_node_group *wng;
 223         struct private_oss_write_data *powd;
 224
 225         powd = para_calloc(sizeof(*powd));
 226         wn->private_data = powd;
 227         if (!wn->btrn) {
 228                 wng = wn->wng;
 229                 return oss_init(wn, wng->samplerate ? *wng->samplerate : 0,
 230                         wng->channels? *wng->channels : 0);
 231         }
 232         powd->fd = -1;
 233         return 1;
 234 }
 235
 236 __malloc static void *oss_parse_config(const char *options)
 237 {
 238         int ret;
 239         struct oss_write_args_info *conf = para_calloc(sizeof(*conf));
 240
 241         PARA_INFO_LOG("options: %s, %zd\n", options, strcspn(options, " \t"));
 242         ret = oss_cmdline_parser_string(options, conf, "oss_write");
 243         if (ret)
 244                 goto err_out;
 245         return conf;
 246 err_out:
 247         free(conf);
 248         return NULL;
 249 }
 250
 251 static void oss_free_config(void *conf)
 252 {
 253         oss_cmdline_parser_free(conf);
 254 }
 255
 256 /**
 257  * The init function of the oss writer.
 258  *
 259  * \param w Pointer to the writer to initialize.
 260  *
 261  * \sa struct writer.
 262  */
 263 void oss_write_init(struct writer *w)
 264 {
 265         struct oss_write_args_info dummy;
 266
 267         oss_cmdline_parser_init(&dummy);
 268         w->open = oss_open;
 269         w->close = oss_close;
 270         w->pre_select_btr = oss_pre_select_btr;
 271         w->post_select_btr = oss_post_select_btr;
 272         w->parse_config = oss_parse_config;
 273         w->free_config = oss_free_config;
 274         w->shutdown = NULL;
 275         w->help = (struct ggo_help) {
 276                 .short_help = oss_write_args_info_help,
 277                 .detailed_help = oss_write_args_info_detailed_help
 278         };
 279         oss_cmdline_parser_free(&dummy);
 280 }