Add snd_pcm_hw_params_get/set_export_buffer()

Add snd_pcm_hw_params_get/set_export_buffer() API functions.
They control to ensure the buffer export to other processes.
If this flag is set, the local buffer of a plugin is exported over IPC shm.
Otherwise the buffer can be handled only locally (no shm).

Also fixed Version file for 1.0.9.

include/pcm.h

@@ -585,6 +585,8 @@ int snd_pcm_hw_params_set_rate_first(snd_pcm_t *pcm, snd_pcm_hw_params_t *params
 int snd_pcm_hw_params_set_rate_last(snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val, int *dir);
 int snd_pcm_hw_params_set_rate_resample(snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val);
 int snd_pcm_hw_params_get_rate_resample(snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val);
+int snd_pcm_hw_params_set_export_buffer(snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val);
+int snd_pcm_hw_params_get_export_buffer(snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val);
 
 int snd_pcm_hw_params_get_period_time(const snd_pcm_hw_params_t *params, unsigned int *val, int *dir);
 int snd_pcm_hw_params_get_period_time_min(const snd_pcm_hw_params_t *params, unsigned int *val, int *dir);

include/sound/asound.h

@@ -344,6 +344,7 @@ enum sndrv_pcm_hw_param {
 };
 
 #define SNDRV_PCM_HW_PARAMS_NORESAMPLE	(1<<0)  /* avoid rate resampling */
+#define SNDRV_PCM_HW_PARAMS_EXPORT_BUFFER	(1<<1)  /* export buffer */
 
 struct sndrv_interval {
 	unsigned int min, max;

src/Versions

@@ -179,6 +179,8 @@ ALSA_1.0.9 {
 
     snd_pcm_hw_params_set_rate_resample;
     snd_pcm_hw_params_get_rate_resample;
+    snd_pcm_hw_params_set_export_buffer;
+    snd_pcm_hw_params_get_export_buffer;
 
     snd_pcm_ioplug_create;
     snd_pcm_ioplug_delete;
@@ -215,4 +217,4 @@ ALSA_1.0.9 {
     snd_timer_ginfo_get_resolution_max;
     snd_timer_ginfo_get_clients;
 
-} ALSA_1.0.5;
+} ALSA_1.0.8;

src/pcm/pcm.c

@@ -3959,6 +3959,36 @@ int snd_pcm_hw_params_get_rate_resample(snd_pcm_t *pcm, snd_pcm_hw_params_t *par
 	return 0;
 }
 
+/**
+ * \brief Restrict a configuration space to allow the buffer accessible from outside
+ * \param pcm PCM handle
+ * \param params Configuration space
+ * \param val 0 = disable, 1 = enable (default) exporting buffer
+ * \return 0 otherwise a negative error code
+ */
+int snd_pcm_hw_params_set_export_buffer(snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int val)
+{
+	assert(pcm && params);
+	if (val)
+		params->flags |= SND_PCM_HW_PARAMS_EXPORT_BUFFER;
+	else
+		params->flags &= ~SND_PCM_HW_PARAMS_EXPORT_BUFFER;
+	return snd_pcm_hw_refine(pcm, params);
+}
+
+/**
+ * \brief Extract buffer accessibility from a configuration space
+ * \param pcm PCM handle
+ * \param *val 0 = disable, 1 = enable exporting buffer
+ * \return 0 otherwise a negative error code
+ */
+int snd_pcm_hw_params_get_export_buffer(snd_pcm_t *pcm, snd_pcm_hw_params_t *params, unsigned int *val)
+{
+	assert(pcm && params && val);
+	*val = params->flags & SND_PCM_HW_PARAMS_EXPORT_BUFFER ? 1 : 0;
+	return 0;
+}
+
 /**
  * \brief Extract period time from a configuration space
  * \param params Configuration space

src/pcm/pcm_local.h

@@ -92,11 +92,8 @@ typedef enum sndrv_pcm_hw_param snd_pcm_hw_param_t;
 /** device can do a kind of synchronized start */
 #define SND_PCM_INFO_SYNC_START SNDRV_PCM_INFO_SYNC_START
 
-#ifndef SNDRV_PCM_HW_PARAMS_NORESAMPLE
-#define SND_PCM_HW_PARAMS_NORESAMPLE (1<<0)
-#else
 #define SND_PCM_HW_PARAMS_NORESAMPLE SNDRV_PCM_HW_PARAMS_NORESAMPLE
-#endif
+#define SND_PCM_HW_PARAMS_EXPORT_BUFFER SNDRV_PCM_HW_PARAMS_EXPORT_BUFFER
 
 typedef struct _snd_pcm_rbptr {
 	snd_pcm_t *master;
@@ -114,7 +111,7 @@ typedef struct _snd_pcm_channel_info {
 	void *addr;			/* base address of channel samples */
 	unsigned int first;		/* offset to first sample in bits */
 	unsigned int step;		/* samples distance in bits */
-	enum { SND_PCM_AREA_SHM, SND_PCM_AREA_MMAP } type;
+	enum { SND_PCM_AREA_SHM, SND_PCM_AREA_MMAP, SND_PCM_AREA_LOCAL } type;
 	union {
 		struct {
 			struct snd_shm_area *area;
@@ -214,9 +211,9 @@ struct _snd_pcm {
 	snd_pcm_rbptr_t appl;
 	snd_pcm_rbptr_t hw;
 	snd_pcm_uframes_t min_align;
-	int mmap_rw: 1,
+	unsigned int mmap_rw: 1;
-	    mmap_shadow: 1,
+	unsigned int mmap_shadow: 1;
-	    donot_close: 1;
+	unsigned int donot_close: 1;
 	snd_pcm_channel_info_t *mmap_channels;
 	snd_pcm_channel_area_t *running_areas;
 	snd_pcm_channel_area_t *stopped_areas;

src/pcm/pcm_mmap.c

@@ -285,9 +285,12 @@ int snd_pcm_channel_info_shm(snd_pcm_t *pcm, snd_pcm_channel_info_t *info, int s
 		return -EINVAL;
 	}
 	info->addr = 0;
-	info->type = SND_PCM_AREA_SHM;
+	if (pcm->hw_flags & SND_PCM_HW_PARAMS_EXPORT_BUFFER) {
-	info->u.shm.shmid = shmid;
+		info->type = SND_PCM_AREA_SHM;
-	info->u.shm.area = NULL;
+		info->u.shm.shmid = shmid;
+		info->u.shm.area = NULL;
+	} else
+		info->type = SND_PCM_AREA_LOCAL;
 	return 0;
 }	
 
@@ -347,6 +350,8 @@ int snd_pcm_mmap(snd_pcm_t *pcm)
 					if (i1->u.shm.shmid != i->u.shm.shmid)
 						continue;
 					break;
+				case SND_PCM_AREA_LOCAL:
+					break;
 				default:
 					assert(0);
 				}
@@ -368,6 +373,7 @@ int snd_pcm_mmap(snd_pcm_t *pcm)
 			case SND_PCM_AREA_SHM:
 				if (i->u.shm.shmid < 0) {
 					int id;
+					/* FIXME: safer permission? */
 					id = shmget(IPC_PRIVATE, size, 0666);
 					if (id < 0) {
 						SYSERR("shmget failed");
@@ -409,6 +415,14 @@ int snd_pcm_mmap(snd_pcm_t *pcm)
 				}
 				i->addr = ptr;
 				break;
+			case SND_PCM_AREA_LOCAL:
+				ptr = malloc(size);
+				if (ptr == NULL) {
+					SYSERR("malloc failed");
+					return -errno;
+				}
+				i->addr = ptr;
+				break;
 			default:
 				assert(0);
 			}
@@ -427,6 +441,8 @@ int snd_pcm_mmap(snd_pcm_t *pcm)
 				if (i1->u.shm.shmid != i->u.shm.shmid)
 					continue;
 				break;
+			case SND_PCM_AREA_LOCAL:
+				break;
 			default:
 				assert(0);
 			}
@@ -494,6 +510,10 @@ int snd_pcm_munmap(snd_pcm_t *pcm)
 				}
 			}
 			break;
+		case SND_PCM_AREA_LOCAL:
+			free(i->addr);
+			i->addr = NULL;
+			break;
 		default:
 			assert(0);
 		}

src/pcm/pcm_shm.c

@@ -288,6 +288,7 @@ static int snd_pcm_shm_hw_params_slave(snd_pcm_t *pcm,
 	snd_pcm_shm_t *shm = pcm->private_data;
 	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
 	int err;
+	params->flags |= SND_PCM_HW_PARAMS_EXPORT_BUFFER;
 	ctrl->cmd = SNDRV_PCM_IOCTL_HW_PARAMS;
 	ctrl->u.hw_params = *params;
 	err = snd_pcm_shm_action(pcm);