alsapid: initial code

This commit is contained in:
Nedko Arnaudov 2010-10-30 23:33:25 +03:00
parent 8f09afb007
commit 920f1b7225
4 changed files with 261 additions and 0 deletions

33
alsapid/alsapid.h Normal file
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/* -*- Mode: C ; c-basic-offset: 2 -*- */
/*
* LADI Session Handler (ladish)
*
* Copyright (C) 2010 Nedko Arnaudov <nedko@arnaudov.name>
*
**************************************************************************
* This file contains interface to alsapid functionality
**************************************************************************
*
* LADI Session Handler is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* LADI Session Handler 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with LADI Session Handler. If not, see <http://www.gnu.org/licenses/>
* or write to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef ALSAPID_H__0A27F284_7538_4791_8023_0FBED929EAF3__INCLUDED
#define ALSAPID_H__0A27F284_7538_4791_8023_0FBED929EAF3__INCLUDED
void alsapid_compose_src_link(int alsa_client_id, char * buffer);
void alsapid_compose_dst_link(char * buffer);
#endif /* #ifndef ALSAPID_H__0A27F284_7538_4791_8023_0FBED929EAF3__INCLUDED */

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alsapid/asound.versions Normal file
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ALSA_0.9 {
global:
snd_*;
_snd_*_open;
_snd_*_dlsym_*;
_snd_*_poll_descriptor;
_snd_pcm_hook_*;
__snd_pcm_hw_params_*;
__snd_pcm_sw_params_*;
__snd_*_dlsym_*;
local:
*;
};

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alsapid/helper.c Normal file
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/* -*- Mode: C ; c-basic-offset: 2 -*- */
/*
* LADI Session Handler (ladish)
*
* Copyright (C) 2010 Nedko Arnaudov <nedko@arnaudov.name>
*
**************************************************************************
* This file contains alsapid helper functionality
**************************************************************************
*
* LADI Session Handler is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* LADI Session Handler 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with LADI Session Handler. If not, see <http://www.gnu.org/licenses/>
* or write to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include "alsapid.h"
void alsapid_compose_src_link(int alsa_client_id, char * buffer)
{
sprintf(buffer, "/tmp/alsapid-%lld-%d", (long long)getuid(), alsa_client_id);
}
void alsapid_compose_dst_link(char * buffer)
{
sprintf(buffer, "/proc/%lld", (long long)getpid());
}

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alsapid/lib.c Normal file
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/* -*- Mode: C ; c-basic-offset: 2 -*- */
/*
* LADI Session Handler (ladish)
*
* Copyright (C) 2010 Nedko Arnaudov <nedko@arnaudov.name>
*
**************************************************************************
* This file contains implementation of the libasound LD_PRELOAD-ed alsapid library
**************************************************************************
*
* LADI Session Handler is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* LADI Session Handler 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with LADI Session Handler. If not, see <http://www.gnu.org/licenses/>
* or write to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#define _GNU_SOURCE
#include <alsa/asoundlib.h>
#include <dlfcn.h>
#include <linux/limits.h>
#include <stdio.h>
#include "alsapid.h"
#define API_VERSION "ALSA_0.9"
// gcc -g -shared -Wl,--version-script=asound.versions -o libasound.so -fPIC -ldl -Wall -Werror lib.c helper.c
// LD_LIBRARY_PATH=alsapid LD_PRELOAD=libasound.so seq24
static void create_symlink(int alsa_client_id)
{
char src[PATH_MAX];
char dst[PATH_MAX];
alsapid_compose_src_link(alsa_client_id, src);
alsapid_compose_dst_link(dst);
//printf("'%s' -> '%s'\n", src, dst);
if (symlink(dst, src) != 0)
{
fprintf(stderr, "symlink(\"%s\", \"%s\") failed with %d (%s)", dst, src, errno, strerror(errno));
}
}
static void destroy_symlink(int alsa_client_id)
{
char src[PATH_MAX];
alsapid_compose_src_link(alsa_client_id, src);
//printf("'%s'\n", src);
if (unlink(src) != 0)
{
fprintf(stderr, "unlink(\"%s\") failed with %d (%s)", src, errno, strerror(errno));
}
}
//static int (* real_snd_seq_open)(snd_seq_t ** handle, const char * name, int streams, int mode);
static int (* real_snd_seq_set_client_name)(snd_seq_t * seq, const char * name);
static int (* real_snd_seq_close)(snd_seq_t * handle);
//static int (* real_snd_seq_create_port)(snd_seq_t * handle, snd_seq_port_info_t * info);
//static int (* real_snd_seq_create_simple_port)(snd_seq_t * seq, const char * name, unsigned int caps, unsigned int type);
void __attribute__ ((constructor)) init(void);
/* Library constructor */
void init(void)
{
// real_snd_seq_open = dlvsym(RTLD_NEXT, "snd_seq_open", API_VERSION);
real_snd_seq_set_client_name = dlvsym(RTLD_NEXT, "snd_seq_set_client_name", API_VERSION);
real_snd_seq_close = dlvsym(RTLD_NEXT, "snd_seq_close", API_VERSION);
// real_snd_seq_create_port = dlvsym(RTLD_NEXT, "snd_seq_create_port", API_VERSION);
// real_snd_seq_create_simple_port = dlvsym(RTLD_NEXT, "snd_seq_create_simple_port", API_VERSION);
}
#define CHECK_FUNC(func) \
if (real_ ## func == NULL) \
{ \
fprintf(stderr, "dlvsym(\"" #func "\", \""API_VERSION"\") failed.\n"); \
return -1; \
}
#if 0
int snd_seq_open(snd_seq_t ** handle, const char * name, int streams, int mode)
{
int ret;
//printf("Attempt to create alsa client '%s', %d streams and mode %d\n", name, streams, mode);
CHECK_FUNC(snd_seq_open);
//printf("real_snd_seq_open = %p\n", real_snd_seq_open);
ret = real_snd_seq_open(handle, name, streams, mode);
if (ret == 0)
{
//printf("alsa client %p (%d) created\n", *handle, snd_seq_client_id(*handle));
}
return ret;
}
#endif
int snd_seq_set_client_name(snd_seq_t * seq, const char * name)
{
int ret;
//printf("Attempt to set alsa client name to '%s' of %p\n", name, seq); getchar();
CHECK_FUNC(snd_seq_set_client_name);
ret = real_snd_seq_set_client_name(seq, name);
//printf("name set?\n"); getchar();
if (ret == 0)
{
//printf("ALSAPID: pid = %lld SETNAME %d '%s'\n", (long long)getpid(), snd_seq_client_id(seq), name);
create_symlink(snd_seq_client_id(seq));
}
return ret;
}
int snd_seq_close(snd_seq_t * handle)
{
CHECK_FUNC(snd_seq_close);
//printf("ALSAPID: pid = %lld CLOSE %d\n", (long long)getpid(), snd_seq_client_id(handle));
destroy_symlink(snd_seq_client_id(handle));
return real_snd_seq_close(handle);
}
#if 0
int snd_seq_create_port(snd_seq_t * handle, snd_seq_port_info_t * info)
{
int ret;
CHECK_FUNC(snd_seq_create_port);
ret = real_snd_seq_create_port(handle, info);
//printf("port created?\n"); getchar();
return ret;
}
int snd_seq_create_simple_port(snd_seq_t * seq, const char * name, unsigned int caps, unsigned int type)
{
int ret;
CHECK_FUNC(snd_seq_create_simple_port);
ret = real_snd_seq_create_simple_port(seq, name, caps, type);
//printf("simple port created?\n"); getchar();
return ret;
}
#endif