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#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include "dbmi.h"
#define READ 0
#define WRITE 1
extern char *getenv();
/*!
\fn
\brief
\return
\param
*/
dbDriver *
db_start_driver(name)
char *name;
{
dbDriver *driver;
dbDbmscap *list, *cur;
char *startup;
int p1[2], p2[2];
int pid;
int stat;
dbConnection connection;
char ebuf[5];
/* Set some enviroment variables which are later read by driver.
* This is necessary when application is running without GISRC file and all
* gis variables are set by application.
* Even if GISRC is set, application may change some variables during runtime,
* if for example reads data from different gdatabase, location or mapset*/
/* setenv() is not portable, putenv() is POSIX, putenv() in glibc 2.0-2.1.1 doesn't conform to SUSv2,
* G_putenv() as well, but that is what we want, makes a copy of string */
if ( G_get_gisrc_mode() == G_GISRC_MODE_MEMORY )
{
sprintf ( ebuf, "%d", G_GISRC_MODE_MEMORY );
G_putenv("GRASS_DB_DRIVER_GISRC_MODE", ebuf); /* to tell driver that it must read variables */
if ( G__getenv ( "DEBUG" ) ) {
G_putenv( "DEBUG", G__getenv ( "DEBUG" ) );
} else {
G_putenv("DEBUG", "0");
}
G_putenv( "GISDBASE", G__getenv("GISDBASE") );
G_putenv( "LOCATION_NAME", G__getenv("LOCATION_NAME") );
G_putenv( "MAPSET", G__getenv("MAPSET") );
}
else
{
/* Warning: GISRC_MODE_MEMORY _must_ be set to G_GISRC_MODE_FILE, because the module can be
* run from an application which previously set enviroment variable to G_GISRC_MODE_MEMORY */
sprintf ( ebuf, "%d", G_GISRC_MODE_FILE );
G_putenv("GRASS_DB_DRIVER_GISRC_MODE", ebuf);
}
/* read the dbmscap file */
if(NULL == (list = db_read_dbmscap()))
return (dbDriver *) NULL;
/* if name is empty use connection.driverName, added by RB 4/2000 */
if( name == '\0' )
{
db_get_connection( &connection );
if(NULL == (name = connection.driverName) )
return (dbDriver *) NULL;
}
/* find this system name */
for (cur = list; cur; cur = cur->next)
if (strcmp (cur->driverName, name) == 0)
break;
if (cur == NULL)
{
char msg[256];
db_free_dbmscap (list);
sprintf (msg, "%s: no such driver available", name );
db_error (msg);
return (dbDriver *) NULL;
}
/* allocate a driver structure */
driver = (dbDriver *) db_malloc (sizeof(dbDriver));
if (driver == NULL)
{
db_free_dbmscap (list);
return (dbDriver *) NULL;
}
/* copy the relevant info from the dbmscap entry into the driver structure */
db_copy_dbmscap_entry (&driver->dbmscap, cur);
startup = driver->dbmscap.startup;
/* free the dbmscap list */
db_free_dbmscap (list);
/* run the driver as a child process and create pipes to its stdin, stdout */
/* open the pipes */
if ((pipe(p1) < 0 ) || (pipe(p2) < 0 ))
{
db_syserror ("can't open any pipes");
return (dbDriver *) NULL;
}
/* create a child */
if ((pid = fork()) < 0)
{
db_syserror ("can't create fork");
return (dbDriver *) NULL;
}
if (pid > 0) /* parent */
{
close(p1[READ]);
close(p2[WRITE]);
/* record driver process id in driver struct */
driver->pid = pid;
/* convert pipes to FILE* */
driver->send = fdopen (p1[WRITE], "w");
driver->recv = fdopen (p2[READ], "r");
/* most systems will have to use unbuffered io to get the send/recv to work */
#ifndef USE_BUFFERED_IO
setbuf (driver->send, NULL);
setbuf (driver->recv, NULL);
#endif
db__set_protocol_fds (driver->send, driver->recv);
if(db__recv_return_code(&stat) !=DB_OK || stat != DB_OK)
driver = NULL;
return driver;
}
else /* child process */
{
close(p1[WRITE]);
close(p2[READ]);
close (0);
close (1);
if (dup(p1[READ]) != 0)
{
db_syserror("dup r");
_exit(127) ;
}
if (dup(p2[WRITE]) != 1)
{
db_syserror("dup w");
_exit(127) ;
}
execl ("/bin/sh", "sh", "-c", startup, 0);
db_syserror ("execl");
return NULL; /* to keep lint, et. al. happy */
}
}
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