alsa-lib/src/pcm/pcm_shm.c

/*
 *  PCM - SHM Client
 *  Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org>
 *
 *
 *   This library is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Library General Public License as
 *   published by the Free Software Foundation; either version 2 of
 *   the License, or (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU Library General Public License for more details.
 *
 *   You should have received a copy of the GNU Library General Public
 *   License along with this library; if not, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */
  
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/shm.h>
#include <sys/socket.h>
#include <sys/poll.h>
#include <sys/un.h>
#include <sys/mman.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <netdb.h>
#include "aserver.h"

typedef struct {
	int socket;
	volatile snd_pcm_shm_ctrl_t *ctrl;
	snd_pcm_mmap_info_t *slave_mmap_info;
} snd_pcm_shm_t;

int receive_fd(int socket, void *data, size_t len, int *fd)
{
    int ret;
    size_t cmsg_len = CMSG_LEN(sizeof(int));
    struct cmsghdr *cmsg = alloca(cmsg_len);
    int *fds = (int *) CMSG_DATA(cmsg);
    struct msghdr msghdr;
    struct iovec vec;

    vec.iov_base = (void *)&data;
    vec.iov_len = len;

    cmsg->cmsg_len = cmsg_len;
    cmsg->cmsg_level = SOL_SOCKET;
    cmsg->cmsg_type = SCM_RIGHTS;
    *fds = -1;

    msghdr.msg_name = NULL;
    msghdr.msg_namelen = 0;
    msghdr.msg_iov = &vec;
    msghdr.msg_iovlen = 1;
    msghdr.msg_control = cmsg;
    msghdr.msg_controllen = cmsg_len;
    msghdr.msg_flags = 0;

    ret = recvmsg(socket, &msghdr, 0);
    if (ret < 0) {
	    SYSERR("recvmsg failed");
	    return -errno;
    }
    *fd = *fds;
    return ret;
}

static int snd_pcm_shm_action(snd_pcm_t *pcm)
{
	snd_pcm_shm_t *shm = pcm->private;
	int err;
	char buf[1];
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	err = write(shm->socket, buf, 1);
	if (err != 1)
		return -EBADFD;
	err = read(shm->socket, buf, 1);
	if (err != 1)
		return -EBADFD;
	if (ctrl->cmd) {
		fprintf(stderr, "Server has not done the cmd\n");
		return -EBADFD;
	}
	return ctrl->result;
}

static int snd_pcm_shm_action_fd(snd_pcm_t *pcm, int *fd)
{
	snd_pcm_shm_t *shm = pcm->private;
	int err;
	char buf[1];
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	err = write(shm->socket, buf, 1);
	if (err != 1)
		return -EBADFD;
	err = receive_fd(shm->socket, buf, 1, fd);
	if (err != 1)
		return -EBADFD;
	if (ctrl->cmd) {
		fprintf(stderr, "Server has not done the cmd\n");
		return -EBADFD;
	}
	return ctrl->result;
}

static int snd_pcm_shm_nonblock(snd_pcm_t *pcm ATTRIBUTE_UNUSED, int nonblock ATTRIBUTE_UNUSED)
{
	return 0;
}

static int snd_pcm_shm_async(snd_pcm_t *pcm, int sig, pid_t pid)
{
	snd_pcm_shm_t *shm = pcm->private;
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	ctrl->cmd = SND_PCM_IOCTL_ASYNC;
	ctrl->u.async.sig = sig;
	if (pid == 0)
		pid = getpid();
	ctrl->u.async.pid = pid;
	return snd_pcm_shm_action(pcm);
}

static int snd_pcm_shm_info(snd_pcm_t *pcm, snd_pcm_info_t * info)
{
	snd_pcm_shm_t *shm = pcm->private;
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	int err;
//	ctrl->u.info = *info;
	ctrl->cmd = SND_PCM_IOCTL_INFO;
	err = snd_pcm_shm_action(pcm);
	if (err < 0)
		return err;
	*info = ctrl->u.info;
	return err;
}

static int snd_pcm_shm_params_info(snd_pcm_t *pcm, snd_pcm_params_info_t * info)
{
	snd_pcm_shm_t *shm = pcm->private;
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	int err;
	ctrl->cmd = SND_PCM_IOCTL_PARAMS_INFO;
	ctrl->u.params_info = *info;
	err = snd_pcm_shm_action(pcm);
	if (err < 0)
		return err;
	*info = ctrl->u.params_info;
	return err;
}

static int snd_pcm_shm_params(snd_pcm_t *pcm, snd_pcm_params_t * params)
{
	snd_pcm_shm_t *shm = pcm->private;
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	int err;
	ctrl->cmd = SND_PCM_IOCTL_PARAMS;
	ctrl->u.params = *params;
	err = snd_pcm_shm_action(pcm);
	if (err < 0)
		return err;
	*params = ctrl->u.params;
	return err;
}

static int snd_pcm_shm_setup(snd_pcm_t *pcm, snd_pcm_setup_t * setup)
{
	snd_pcm_shm_t *shm = pcm->private;
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	int err;
	ctrl->cmd = SND_PCM_IOCTL_SETUP;
	// ctrl->u.setup = *setup;
	err = snd_pcm_shm_action(pcm);
	if (err < 0)
		return err;
	*setup = ctrl->u.setup;
	return err;
}

static int snd_pcm_shm_channel_info(snd_pcm_t *pcm, snd_pcm_channel_info_t * info)
{
	snd_pcm_shm_t *shm = pcm->private;
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	int err;
	ctrl->cmd = SND_PCM_IOCTL_CHANNEL_INFO;
	ctrl->u.channel_info = *info;
	err = snd_pcm_shm_action(pcm);
	if (err < 0)
		return err;
	*info = ctrl->u.channel_info;
	return err;
}

static int snd_pcm_shm_channel_params(snd_pcm_t *pcm, snd_pcm_channel_params_t * params)
{
	snd_pcm_shm_t *shm = pcm->private;
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	int err;
	ctrl->cmd = SND_PCM_IOCTL_CHANNEL_PARAMS;
	ctrl->u.channel_params = *params;
	err = snd_pcm_shm_action(pcm);
	if (err < 0)
		return err;
	*params = ctrl->u.channel_params;
	return err;
}

static void *convert_addr(void *addr, size_t count, snd_pcm_mmap_info_t *old, snd_pcm_mmap_info_t *new)
{
	size_t k;
	size_t mindist = ULONG_MAX;
	int idx = -1;
	for (k = 0; k < count; ++k) {
		if (addr >= old[k].addr) {
			size_t dist = addr - old[k].addr;
			if (dist < mindist) {
				mindist = dist;
				idx = k;
			}
		}
	}
	assert(idx >= 0);
	return new[idx].addr + mindist;
}

static int snd_pcm_shm_channel_setup(snd_pcm_t *pcm, snd_pcm_channel_setup_t * setup)
{
	snd_pcm_shm_t *shm = pcm->private;
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	int err;
	ctrl->cmd = SND_PCM_IOCTL_CHANNEL_SETUP;
	ctrl->u.channel_setup = *setup;
	err = snd_pcm_shm_action(pcm);
	if (err < 0)
		return err;
	*setup = ctrl->u.channel_setup;
	if (pcm->mmap_info) {
		setup->running_area.addr = convert_addr(setup->running_area.addr, pcm->mmap_info_count, shm->slave_mmap_info, pcm->mmap_info);
		setup->stopped_area.addr = convert_addr(setup->stopped_area.addr, pcm->mmap_info_count, shm->slave_mmap_info, pcm->mmap_info);
	}
	return err;
}

static int snd_pcm_shm_status(snd_pcm_t *pcm, snd_pcm_status_t * status)
{
	snd_pcm_shm_t *shm = pcm->private;
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	int err;
	ctrl->cmd = SND_PCM_IOCTL_STATUS;
	// ctrl->u.status = *status;
	err = snd_pcm_shm_action(pcm);
	if (err < 0)
		return err;
	*status = ctrl->u.status;
	return err;
}

static int snd_pcm_shm_state(snd_pcm_t *pcm)
{
	snd_pcm_shm_t *shm = pcm->private;
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	ctrl->cmd = SND_PCM_IOCTL_STATE;
	return snd_pcm_shm_action(pcm);
}

static int snd_pcm_shm_delay(snd_pcm_t *pcm, ssize_t *delayp)
{
	snd_pcm_shm_t *shm = pcm->private;
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	int err;
	ctrl->cmd = SND_PCM_IOCTL_DELAY;
	err = snd_pcm_shm_action(pcm);
	if (err < 0)
		return err;
	*delayp = ctrl->u.delay.frames;
	return err;
}

static ssize_t snd_pcm_shm_avail_update(snd_pcm_t *pcm)
{
	snd_pcm_shm_t *shm = pcm->private;
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	int err;
	ctrl->cmd = SND_PCM_IOCTL_AVAIL_UPDATE;
	err = snd_pcm_shm_action(pcm);
	if (err < 0)
		return err;
	return err;
}

static int snd_pcm_shm_prepare(snd_pcm_t *pcm)
{
	snd_pcm_shm_t *shm = pcm->private;
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	ctrl->cmd = SND_PCM_IOCTL_PREPARE;
	return snd_pcm_shm_action(pcm);
}

static int snd_pcm_shm_start(snd_pcm_t *pcm)
{
	snd_pcm_shm_t *shm = pcm->private;
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	ctrl->cmd = SND_PCM_IOCTL_START;
	return snd_pcm_shm_action(pcm);
}

static int snd_pcm_shm_drop(snd_pcm_t *pcm)
{
	snd_pcm_shm_t *shm = pcm->private;
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	ctrl->cmd = SND_PCM_IOCTL_DROP;
	return snd_pcm_shm_action(pcm);
}

static int snd_pcm_shm_drain(snd_pcm_t *pcm)
{
	snd_pcm_shm_t *shm = pcm->private;
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	int err;
	ctrl->cmd = SND_PCM_IOCTL_DRAIN;
	err = snd_pcm_shm_action(pcm);
	if (err < 0)
		return err;
	if (!(pcm->mode & SND_PCM_NONBLOCK))
		snd_pcm_wait(pcm, -1);
	return err;
}

static int snd_pcm_shm_pause(snd_pcm_t *pcm, int enable)
{
	snd_pcm_shm_t *shm = pcm->private;
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	ctrl->cmd = SND_PCM_IOCTL_PAUSE;
	ctrl->u.pause.enable = enable;
	return snd_pcm_shm_action(pcm);
}

static ssize_t snd_pcm_shm_rewind(snd_pcm_t *pcm, size_t frames)
{
	snd_pcm_shm_t *shm = pcm->private;
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	ctrl->cmd = SND_PCM_IOCTL_REWIND;
	ctrl->u.rewind.frames = frames;
	return snd_pcm_shm_action(pcm);
}

static int snd_pcm_shm_mmap(snd_pcm_t *pcm)
{
	snd_pcm_shm_t *shm = pcm->private;
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	int count, k, err, fd;
	ctrl->cmd = SND_PCM_IOCTL_MMAP;
	count = snd_pcm_shm_action(pcm);
	if (count < 0)
		return count;
	pcm->mmap_info_count = count;
	pcm->mmap_info = malloc(count * sizeof(*pcm->mmap_info));
	shm->slave_mmap_info = malloc(count * sizeof(*shm->slave_mmap_info));
	for (k = 0; k < count; ++k) {
		snd_pcm_mmap_info_t *i = &pcm->mmap_info[k];
		void *ptr;
		ctrl->cmd = SND_PCM_IOCTL_MMAP_INFO;
		ctrl->u.mmap_info.index = k;
		err = snd_pcm_shm_action_fd(pcm, &fd);
		if (err < 0)
			return err;
		shm->slave_mmap_info[k] = ctrl->u.mmap_info;
		*i = ctrl->u.mmap_info;
		if (i->type == SND_PCM_MMAP_KERNEL) {
			i->u.kernel.fd = fd;
			ptr = mmap(NULL, i->size, PROT_WRITE | PROT_READ,
				   MAP_FILE | MAP_SHARED, 
				   fd, SND_PCM_MMAP_OFFSET_DATA);
			close(fd);
			if (ptr == MAP_FAILED || ptr == NULL) {
				SYSERR("mmap failed");
				free(pcm->mmap_info);
				return -errno;
			}
		} else {
			ptr = shmat(i->u.user.shmid, 0, 0);
			if (ptr == (void*)-1) {
				SYSERR("shmat failed");
				free(pcm->mmap_info);
				return -errno;
			}
		}
		i->addr = ptr;
	}
	return 0;
}

static int snd_pcm_shm_munmap(snd_pcm_t *pcm)
{
	snd_pcm_shm_t *shm = pcm->private;
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	int err;
	unsigned int k;
	ctrl->cmd = SND_PCM_IOCTL_MUNMAP;
	err = snd_pcm_shm_action(pcm);
	if (err < 0)
		return err;
	for (k = 0; k < pcm->mmap_info_count; ++k) {
		snd_pcm_mmap_info_t *i = &pcm->mmap_info[k];
		if (i->type == SND_PCM_MMAP_KERNEL) {
			err = munmap(i->addr, i->size);
			if (err < 0)
				SYSERR("munmap failed");
			return -errno;
		} else {
			err = shmdt(i->addr);
			if (err < 0)
				SYSERR("shmdt failed");
			return -errno;
		}
	}
	pcm->mmap_info_count = 0;
	free(pcm->mmap_info);
	free(shm->slave_mmap_info);
	pcm->mmap_info = 0;
	shm->slave_mmap_info = 0;
	return ctrl->result;
}

static ssize_t snd_pcm_shm_mmap_forward(snd_pcm_t *pcm, size_t size)
{
	snd_pcm_shm_t *shm = pcm->private;
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	ctrl->cmd = SND_PCM_IOCTL_MMAP_FORWARD;
	ctrl->u.mmap_forward.frames = size;
	return snd_pcm_shm_action(pcm);
}

static int snd_pcm_shm_poll_descriptor(snd_pcm_t *pcm)
{
	snd_pcm_shm_t *shm = pcm->private;
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	int fd, err;
	ctrl->cmd = SND_PCM_IOCTL_POLL_DESCRIPTOR;
	err = snd_pcm_shm_action_fd(pcm, &fd);
	if (err < 0)
		return err;
	return fd;
}

static int snd_pcm_shm_channels_mask(snd_pcm_t *pcm ATTRIBUTE_UNUSED,
					bitset_t *cmask ATTRIBUTE_UNUSED)
{
	return 0;
}

static int snd_pcm_shm_close(snd_pcm_t *pcm)
{
	snd_pcm_shm_t *shm = pcm->private;
	volatile snd_pcm_shm_ctrl_t *ctrl = shm->ctrl;
	int result;
	if (!(pcm->mode & SND_PCM_NONBLOCK) &&
	    snd_pcm_shm_state(pcm) == SND_PCM_STATE_RUNNING)
		snd_pcm_shm_drain(pcm);
	ctrl->cmd = SND_PCM_IOCTL_CLOSE;
	result = snd_pcm_shm_action(pcm);
	shmdt((void *)ctrl);
	close(shm->socket);
	close(pcm->poll_fd);
	free(shm);
	return result;
}

static void snd_pcm_shm_dump(snd_pcm_t *pcm, FILE *fp)
{
	fprintf(fp, "Shm PCM\n");
	if (pcm->valid_setup) {
		fprintf(fp, "\nIts setup is:\n");
		snd_pcm_dump_setup(pcm, fp);
	}
}

snd_pcm_ops_t snd_pcm_shm_ops = {
	close: snd_pcm_shm_close,
	info: snd_pcm_shm_info,
	params_info: snd_pcm_shm_params_info,
	params: snd_pcm_shm_params,
	setup: snd_pcm_shm_setup,
	channel_info: snd_pcm_shm_channel_info,
	channel_params: snd_pcm_shm_channel_params,
	channel_setup: snd_pcm_shm_channel_setup,
	dump: snd_pcm_shm_dump,
	nonblock: snd_pcm_shm_nonblock,
	async: snd_pcm_shm_async,
	mmap: snd_pcm_shm_mmap,
	munmap: snd_pcm_shm_munmap,
};

snd_pcm_fast_ops_t snd_pcm_shm_fast_ops = {
	status: snd_pcm_shm_status,
	state: snd_pcm_shm_state,
	delay: snd_pcm_shm_delay,
	prepare: snd_pcm_shm_prepare,
	start: snd_pcm_shm_start,
	drop: snd_pcm_shm_drop,
	drain: snd_pcm_shm_drain,
	pause: snd_pcm_shm_pause,
	rewind: snd_pcm_shm_rewind,
	writei: snd_pcm_mmap_writei,
	writen: snd_pcm_mmap_writen,
	readi: snd_pcm_mmap_readi,
	readn: snd_pcm_mmap_readn,
	channels_mask: snd_pcm_shm_channels_mask,
	avail_update: snd_pcm_shm_avail_update,
	mmap_forward: snd_pcm_shm_mmap_forward,
};

static int make_local_socket(const char *filename)
{
	size_t l = strlen(filename);
	size_t size = offsetof(struct sockaddr_un, sun_path) + l;
	struct sockaddr_un *addr = alloca(size);
	int sock;

	sock = socket(PF_LOCAL, SOCK_STREAM, 0);
	if (sock < 0) {
		SYSERR("socket failed");
		return -errno;
	}
	
	addr->sun_family = AF_LOCAL;
	memcpy(addr->sun_path, filename, l);

	if (connect(sock, (struct sockaddr *) addr, size) < 0) {
		SYSERR("connect failed");
		return -errno;
	}
	return sock;
}

#if 0
static int make_inet_socket(const char *host, int port)
{
	struct sockaddr_in addr;
	int sock;
	struct hostent *h = gethostbyname(host);
	if (!h)
		return -ENOENT;

	sock = socket(PF_INET, SOCK_STREAM, 0);
	if (sock < 0) {
		SYSERR("socket failed");
		return -errno;
	}
	
	addr.sin_family = AF_INET;
	addr.sin_port = htons(port);
	memcpy(&addr.sin_addr, h->h_addr_list[0], sizeof(struct in_addr));

	if (connect(sock, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
		SYSERR("connect failed");
		return -errno;
	}
	return sock;
}
#endif

int snd_pcm_shm_open(snd_pcm_t **pcmp, char *name, char *socket, char *sname, int stream, int mode)
{
	snd_pcm_t *pcm;
	snd_pcm_shm_t *shm = NULL;
	snd_client_open_request_t *req;
	snd_client_open_answer_t ans;
	size_t snamelen, reqlen;
	int err;
	int result;
	snd_pcm_shm_ctrl_t *ctrl = NULL;
	int sock = -1;
	snamelen = strlen(sname);
	if (snamelen > 255)
		return -EINVAL;

	result = make_local_socket(socket);
	if (result < 0) {
		ERR("server for socket %s is not running", socket);
		goto _err;
	}
	sock = result;

	reqlen = sizeof(*req) + snamelen;
	req = alloca(reqlen);
	memcpy(req->name, sname, snamelen);
	req->dev_type = SND_DEV_TYPE_PCM;
	req->transport_type = SND_TRANSPORT_TYPE_SHM;
	req->stream = stream;
	req->mode = mode;
	req->namelen = snamelen;
	err = write(sock, req, reqlen);
	if (err < 0) {
		SYSERR("write error");
		result = -errno;
		goto _err;
	}
	if ((size_t) err != reqlen) {
		ERR("write size error");
		result = -EINVAL;
		goto _err;
	}
	err = read(sock, &ans, sizeof(ans));
	if (err < 0) {
		SYSERR("read error");
		result = -errno;
		goto _err;
	}
	if (err != sizeof(ans)) {
		ERR("read size error");
		result = -EINVAL;
		goto _err;
	}
	result = ans.result;
	if (result < 0)
		goto _err;

	ctrl = shmat(ans.cookie, 0, 0);
	if (!ctrl) {
		SYSERR("shmat error");
		result = -errno;
		goto _err;
	}
		
	shm = calloc(1, sizeof(snd_pcm_shm_t));
	if (!shm) {
		result = -ENOMEM;
		goto _err;
	}

	shm->socket = sock;
	shm->ctrl = ctrl;

	pcm = calloc(1, sizeof(snd_pcm_t));
	if (!pcm) {
		result = -ENOMEM;
		goto _err;
	}
	if (name)
		pcm->name = strdup(name);
	pcm->type = SND_PCM_TYPE_SHM;
	pcm->stream = stream;
	pcm->mode = mode;
	pcm->mmap_auto = 1;
	pcm->ops = &snd_pcm_shm_ops;
	pcm->op_arg = pcm;
	pcm->fast_ops = &snd_pcm_shm_fast_ops;
	pcm->fast_op_arg = pcm;
	pcm->private = shm;
	err = snd_pcm_shm_poll_descriptor(pcm);
	if (err < 0) {
		snd_pcm_close(pcm);
		return err;
	}
	pcm->poll_fd = err;
	pcm->hw_ptr = &ctrl->hw_ptr;
	pcm->appl_ptr = &ctrl->appl_ptr;
	*pcmp = pcm;
	return 0;

 _err:
	close(sock);
	if (ctrl)
		shmdt(ctrl);
	if (shm)
		free(shm);
	return result;
}

int is_local(struct hostent *hent)
{
	int s;
	int err;
	struct ifconf conf;
	size_t numreqs = 10;
	size_t i;
	struct in_addr *haddr = (struct in_addr*) hent->h_addr_list[0];
	
	s = socket(PF_INET, SOCK_STREAM, 0);
	if (s < 0) {
		SYSERR("socket failed");
		return -errno;
	}
	
	conf.ifc_len = numreqs * sizeof(struct ifreq);
	conf.ifc_buf = malloc(conf.ifc_len);
	while (1) {
		err = ioctl(s, SIOCGIFCONF, &conf);
		if (err < 0) {
			SYSERR("SIOCGIFCONF failed");
			return -errno;
		}
		if ((size_t)conf.ifc_len < numreqs * sizeof(struct ifreq))
			break;
		numreqs *= 2;
		conf.ifc_len = numreqs * sizeof(struct ifreq);
		conf.ifc_buf = realloc(conf.ifc_buf, conf.ifc_len);
	}
	numreqs = conf.ifc_len / sizeof(struct ifreq);
	for (i = 0; i < numreqs; ++i) {
		struct ifreq *req = &conf.ifc_req[i];
		struct sockaddr_in *sin = (struct sockaddr_in *)&req->ifr_addr;
		sin->sin_family = AF_INET;
		err = ioctl(s, SIOCGIFADDR, req);
		if (err < 0)
			continue;
		if (haddr->s_addr == sin->sin_addr.s_addr)
			break;
	}
	close(s);
	free(conf.ifc_buf);
	return i < numreqs;
}

int _snd_pcm_shm_open(snd_pcm_t **pcmp, char *name, snd_config_t *conf,
		      int stream, int mode)
{
	snd_config_iterator_t i;
	char *server = NULL;
	char *sname = NULL;
	snd_config_t *sconfig;
	char *host = NULL;
	char *socket = NULL;
	long port = -1;
	int err;
	int local;
	struct hostent *h;
	snd_config_foreach(i, conf) {
		snd_config_t *n = snd_config_entry(i);
		if (strcmp(n->id, "comment") == 0)
			continue;
		if (strcmp(n->id, "type") == 0)
			continue;
		if (strcmp(n->id, "stream") == 0)
			continue;
		if (strcmp(n->id, "server") == 0) {
			err = snd_config_string_get(n, &server);
			if (err < 0) {
				ERR("Invalid type for server");
				return -EINVAL;
			}
			continue;
		}
		if (strcmp(n->id, "sname") == 0) {
			err = snd_config_string_get(n, &sname);
			if (err < 0) {
				ERR("Invalid type for sname");
				return -EINVAL;
			}
			continue;
		}
		ERR("Unknown field: %s", n->id);
		return -EINVAL;
	}
	if (!sname) {
		ERR("sname is not defined");
		return -EINVAL;
	}
	if (!server) {
		ERR("server is not defined");
		return -EINVAL;
	}
	err = snd_config_searchv(snd_config, &sconfig, "server", server, 0);
	if (err < 0) {
		ERR("Unknown server %s", server);
		return -EINVAL;
	}
	snd_config_foreach(i, sconfig) {
		snd_config_t *n = snd_config_entry(i);
		if (strcmp(n->id, "comment") == 0)
			continue;
		if (strcmp(n->id, "host") == 0) {
			err = snd_config_string_get(n, &host);
			if (err < 0) {
				ERR("Invalid type for host");
				return -EINVAL;
			}
			continue;
		}
		if (strcmp(n->id, "socket") == 0) {
			err = snd_config_string_get(n, &socket);
			if (err < 0) {
				ERR("Invalid type for socket");
				return -EINVAL;
			}
			continue;
		}
		if (strcmp(n->id, "port") == 0) {
			err = snd_config_integer_get(n, &port);
			if (err < 0) {
				ERR("Invalid type for port");
				return -EINVAL;
			}
			continue;
		}
		ERR("Unknown field: %s", n->id);
		return -EINVAL;
	}

	if (!host) {
		ERR("host is not defined");
		return -EINVAL;
	}
	if (!socket) {
		ERR("socket is not defined");
		return -EINVAL;
	}
	h = gethostbyname(host);
	if (!h) {
		ERR("Cannot resolve %s", host);
		return -EINVAL;
	}
	local = is_local(h);
	if (!local) {
		ERR("%s is not the local host", host);
		return -EINVAL;
	}
	return snd_pcm_shm_open(pcmp, name, socket, sname, stream, mode);
}