lcdproc/server/driver.c

/*
 * driver.c
 * This file is part of LCDd, the lcdproc server.
 *
 * This file is released under the GNU General Public License. Refer to the
 * COPYING file distributed with this package.
 *
 * Copyright (c) 2001, Joris Robijn
 *
 *
 * This code does all actions on the driver object.
 *
 */

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <sys/errno.h>
#include <dlfcn.h>

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "shared/report.h"
#include "configfile.h"

#include "driver.h"
#include "drivers.h"
#include "drivers/lcd.h"
/* lcd.h is used for the driver API definition */


typedef struct driver_symbols {
	char *name;
	short offset; /* offset in Driver structure */
	short required;
} DriverSymbols;

DriverSymbols driver_symbols[] = {
	{ "api_version", offsetof(Driver, api_version), 1 },
	{ "stay_in_foreground", offsetof(Driver, stay_in_foreground), 1 },
	{ "supports_multiple", offsetof(Driver, supports_multiple), 1 },
	{ "symbol_prefix", offsetof(Driver, symbol_prefix), 1 },
	{ "init", offsetof(Driver, init), 1 },
	{ "close", offsetof(Driver, close), 1 },
	{ "width", offsetof(Driver, width), 1 },
	{ "height", offsetof(Driver, height), 1 },
	{ "clear", offsetof(Driver, clear), 1 },
	{ "flush", offsetof(Driver, flush), 1 },
	{ "string", offsetof(Driver, string), 1 },
	{ "chr", offsetof(Driver, chr), 1 },
	{ "vbar", offsetof(Driver, vbar), 0 },
	{ "hbar", offsetof(Driver, hbar), 0 },
	{ "num", offsetof(Driver, num), 0 },
	{ "heartbeat", offsetof(Driver, heartbeat), 0 },
	{ "icon", offsetof(Driver, icon), 0 },
	{ "cursor", offsetof(Driver, cursor), 0 },
	{ "set_char", offsetof(Driver, set_char), 0 },
	{ "get_free_chars", offsetof(Driver, get_free_chars), 0 },
	{ "cellwidth", offsetof(Driver, cellwidth), 0 },
	{ "cellheight", offsetof(Driver, cellheight), 0 },
	{ "get_contrast", offsetof(Driver, get_contrast), 0 },
	{ "set_contrast", offsetof(Driver, set_contrast), 0 },
	{ "get_brightness", offsetof(Driver, get_brightness), 0 },
	{ "set_brightness", offsetof(Driver, set_brightness), 0 },
	{ "backlight", offsetof(Driver, backlight), 0 },
	{ "output", offsetof(Driver, output), 0 },
	{ "get_key", offsetof(Driver, get_key), 0 },
	{ "get_info", offsetof(Driver, get_info), 0 },
	{ NULL, 0, 0 }
};



/* Functions for the driver */
static int request_display_width();
static int request_display_height();
static int driver_store_private_ptr(Driver * driver, void * private_data);


Driver *
driver_load( char * name, char * filename, char * args )
{
	Driver * driver = NULL;
	int res;

	report( RPT_INFO, "driver_load( name=\"%.40s\", filename=\"%.80s\", args=\"%.80s\")", name, filename, args );

	/* Allocate memory for new driver struct */
	driver = malloc( sizeof( Driver ));
	memset( driver, 0, sizeof (Driver));

	/* And store its name and filename */
	driver->name = malloc( strlen( name ) + 1 );
	strcpy( driver->name, name );
	driver->filename = malloc( strlen( filename ) + 1 );
	strcpy( driver->filename, filename );

	/* Load and bind the driver module and locate the symbols */
	if( driver_bind_module( driver ) < 0 ) {
		report( RPT_ERR, "Driver [%.40s] binding failed", name );
		free( driver->name );
		free( driver->filename );
		free( driver );
		return NULL;
	}

	/* Check module version */
	if( strcmp( *(driver->api_version), API_VERSION ) != 0 ) {
		report( RPT_ERR, "Driver [%.40s] is of an incompatible version", name );
		driver_unbind_module( driver );
		free( driver->name );
		free( driver->filename );
		free( driver );
		return NULL;
	}

	/* Call the init function */
	debug( RPT_DEBUG, "Calling driver [%.40s] init function", driver->name );
	res = driver->init( driver, args );
	if( res < 0 ) {
		report( RPT_ERR, "Driver [%.40s] init failed, return code < 0", driver->name );
		/* Driver load failed, driver should not be added to list
		 * Free driver structure again
		 */
		driver_unbind_module( driver );
		free( driver->name );
		free( driver->filename );
		free( driver );
		return NULL;
	}

	debug( RPT_NOTICE, "Driver [%.40s] loaded", driver->name );

	return driver;
}


int
driver_unload( Driver * driver )
{
	debug( RPT_NOTICE, "Closing driver [%.40s]", driver->name );
	if( driver->close )
		driver->close (driver);

	/* Unlaod the module */
	driver_unbind_module( driver );

	/* Free its data */
	free( driver->filename );
	free( driver->name );
	free( driver );
	debug( RPT_DEBUG, "Driver unloaded" );

	return 0;
}


int
driver_bind_module( Driver * driver )
{
	int i;
	int missing_symbols = 0;

	/* Load the module */
	driver->module_handle = dlopen( driver->filename, RTLD_NOW );
	if( driver->module_handle == NULL ) {
		report( RPT_ERR, "Could not dlopen driver module %.40s: %s", driver->filename, dlerror() );
		return -1;
	}

	/* And locate the symbols */
	for( i=0; driver_symbols[i].name; i++ ) {
		void (**p)();
		p = (void(**)() ) ((size_t)driver + (driver_symbols[i].offset));
		*p = NULL;

		/* Add the symbol_prefix */
		if( driver->symbol_prefix ) {
			char *s = malloc( strlen( *(driver->symbol_prefix) ) + strlen( driver_symbols[i].name ) + 1 );
			strcpy( s, *(driver->symbol_prefix) ) ;
			strcat( s, driver_symbols[i].name );
			debug( RPT_DEBUG, "finding symbol: %s", s );
			*p = dlsym( driver->module_handle, s );
			free( s );
		}
		/* Retrieve the symbol */
		if( !*p ) {
			debug( RPT_DEBUG, "finding symbol: %s", driver_symbols[i].name );
			*p = dlsym( driver->module_handle, driver_symbols[i].name );
		}

		if( *p ) {
			debug( RPT_DEBUG, "found symbol at: %p", *p );
		}

		/* Was the symbol required but not found ? */
		if( !*p && driver_symbols[i].required ) {
			report( RPT_ERR, "Module [%.40s] does not have required symbol: %s", driver->name, driver_symbols[i].name );
			missing_symbols = 1;
		}
	}

	/* If errors, leave now while we can :) */
	if( missing_symbols ) {
  		report( RPT_ERR, "Driver [%.40s] does not have all obligatory symbols", driver->name );
		dlclose( driver->module_handle );
		return -1;
	}


	/* Add our exported functions */

	/* Config file functions */
	driver->config_get_bool		= config_get_bool;
	driver->config_get_int		= config_get_int;
	driver->config_get_float	= config_get_float;
	driver->config_get_string	= config_get_string;
	driver->config_has_section	= config_has_section;
	driver->config_has_key		= config_has_key;

	/* Reporting */
	driver->report			= report;

	/* Driver private data */
	driver->store_private_ptr	= driver_store_private_ptr;

	/* Display size request */
	driver->request_display_width	= request_display_width;
	driver->request_display_height	= request_display_height;

	return 0;
}


int
driver_unbind_module( Driver * driver )
{
	dlclose( driver->module_handle );

	return 0;
}


bool
driver_does_output( Driver * driver )
{
	return (driver->width != NULL
		|| driver->height != NULL
		|| driver->clear != NULL
		|| driver->string != NULL
		|| driver->chr != NULL ) ? 1 : 0;
}


bool
driver_does_input( Driver * driver )
{
	return (driver->getkey != NULL
		|| driver->get_key != NULL ) ? 1 : 0;
}


bool
driver_stay_in_foreground( Driver * driver )
{
	return *driver->stay_in_foreground;
}


bool
driver_supports_multiple( Driver * driver )
{
	return *driver->supports_multiple;
}


static int
driver_store_private_ptr(Driver * driver, void * private_data)
{
	report( RPT_INFO, "driver_store_private_ptr( driver=%p, ptr=%p )", driver, private_data );

	driver->private_data = private_data;
	return 0;
}


static int
request_display_width()
{
	if( !display_props )
		return 0;
	return display_props->width;
}


static int
request_display_height()
{
	if( !display_props )
		return 0;
	return display_props->height;
}