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