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/*
* VBI proxy wrapper for proxy-unaware clients
*
* Copyright (C) 2004 Tom Zoerner
*
* This program 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.
*
* 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
*
*
* Description:
*
* This is a small wrapper which executes the VBI application given
* on the command line while overloading several C library calls
* (such as open(2) and read(2)) so that the application can be forced
* to access VBI devices via the VBI proxy instead of device files
* directly.
*
* LD_PRELOAD is used to intercept C library calls and call functions
* in the libvbichain shared library instead. Parameters given on the
* command line (e.g. device path) are passed to the library by means
* of environment variables.
*
* $Log: chains.c,v $
* Revision 1.4 2008/07/26 06:22:28 mschimek
* Changed the license to GPLv2+ with Tom's permission.
*
* Revision 1.3 2007/11/27 17:39:34 mschimek
* *** empty log message ***
*
* Revision 1.2 2006/05/22 09:02:43 mschimek
* s/vbi_asprintf/asprintf.
*
* Revision 1.1 2004/10/25 16:52:43 mschimek
* main: Replaced sprintf by asprintf and fixed p_env3.
* Added from proxy-18.bak.
*
*/
static const char rcsid[] = "$Id: chains.c,v 1.4 2008/07/26 06:22:28 mschimek Exp $";
#include "config.h"
#ifdef ENABLE_PROXY
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <signal.h>
#include <assert.h>
#include "src/misc.h" /* asprintf() */
#define dprintf1(fmt, arg...) do {if (opt_debug_level >= 1) fprintf(stderr, "proxyd: " fmt, ## arg);} while (0)
#define dprintf2(fmt, arg...) do {if (opt_debug_level >= 2) fprintf(stderr, "proxyd: " fmt, ## arg);} while (0)
static char * opt_vbi_device = "";
static int opt_debug_level = 0;
/* ---------------------------------------------------------------------------
** Print usage and exit
*/
static void
usage_exit( const char *argv0, const char *argvn, const char * reason )
{
fprintf(stderr, "%s: %s: %s\n"
"Usage: %s [options ...] command ...\n"
" -dev <path> : VBI device path (default: any VBI device)\n"
" -debug <level> : enable debug output: 1=warnings, 2=all\n"
" -help : this message\n"
" -- : stop option processing\n",
argv0, reason, argvn, argv0);
exit(1);
}
/* ---------------------------------------------------------------------------
** Parse numeric value in command line options
*/
static int
parse_argv_numeric( char * p_number, int * p_value )
{
char * p_num_end;
if (*p_number != 0)
{
*p_value = strtol(p_number, &p_num_end, 0);
return (*p_num_end == 0);
}
else
return 0;
}
/* ---------------------------------------------------------------------------
** Parse command line options
*/
static void
parse_argv( int argc, char * argv[], int * p_arg_off )
{
struct stat stb;
int arg_val;
int arg_idx = 1;
while (arg_idx < argc)
{
if (strcasecmp(argv[arg_idx], "-dev") == 0)
{
if (arg_idx + 1 < argc)
{
if (stat(argv[arg_idx + 1], &stb) == -1)
usage_exit(argv[0], argv[arg_idx +1], strerror(errno));
if (!S_ISCHR(stb.st_mode))
usage_exit(argv[0], argv[arg_idx +1], "not a character device");
if (access(argv[arg_idx + 1], R_OK | W_OK) == -1)
usage_exit(argv[0], argv[arg_idx +1], strerror(errno));
opt_vbi_device = argv[arg_idx + 1];
arg_idx += 2;
}
else
usage_exit(argv[0], argv[arg_idx], "missing mode keyword after");
}
else if (strcasecmp(argv[arg_idx], "-debug") == 0)
{
if ((arg_idx + 1 < argc) && parse_argv_numeric(argv[arg_idx + 1], &arg_val))
{
opt_debug_level = arg_val;
arg_idx += 2;
}
else
usage_exit(argv[0], argv[arg_idx], "missing debug level after");
}
else if (strcasecmp(argv[arg_idx], "-help") == 0)
{
usage_exit(argv[0], "", "the following options are available");
}
else if (strcmp(argv[arg_idx], "--") == 0)
{
arg_idx += 1;
break;
}
else if (*argv[arg_idx] == '-')
{
usage_exit(argv[0], argv[arg_idx], "unknown option or argument");
}
else
break;
}
if (arg_idx >= argc)
{
usage_exit(argv[0], "", "name of application to launch is missing");
}
* p_arg_off = arg_idx;
}
/* ----------------------------------------------------------------------------
** Main
*/
#define putenv_printf(bp, tmpl, args...) \
do { \
asprintf (&(bp), tmpl ,##args ); \
assert (NULL != (bp)); \
putenv (bp); \
} while (0)
int
main( int argc, char ** argv )
{
int arg_off;
char * p_old_preload;
char * p_env1;
char * p_env2;
char * p_env3;
char * p_env4;
parse_argv(argc, argv, &arg_off);
putenv_printf(p_env1, "VBIPROXY_DEVICE=%s", opt_vbi_device);
putenv_printf(p_env2, "VBIPROXY_DEBUG=%d", opt_debug_level);
putenv_printf(p_env3, "VBIPROXY_CLIENT=%s [vbi-chains]", argv[arg_off]);
p_old_preload = getenv("LD_PRELOAD");
if (p_old_preload == NULL)
{ /* no preload defined yet */
putenv_printf(p_env4, "LD_PRELOAD=%s", LIBZVBI_CHAINS_PATH);
}
else
{ /* prepend preload to existing definition */
putenv_printf(p_env4, "LD_PRELOAD=%s:%s",
LIBZVBI_CHAINS_PATH, p_old_preload);
}
if (opt_debug_level > 0)
{
fprintf(stderr, "vbi-chains: Environment set-up:\n"
"\t%s\n\t%s\n\t%s\n\t%s\n",
p_env1, p_env2, p_env3, p_env4);
}
execvp(argv[arg_off], argv + arg_off);
fprintf(stderr, "vbi_chains: Failed to start %s: %s\n",
argv[arg_off], strerror(errno));
exit(-1);
return -1;
}
#endif /* ENABLE_PROXY */
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