/* NAME
 *     do_unix.c
 *
 * DESCRIPTION
 *     Executes a unix command with popen, returns the results as a set.
 *     Note that the command is executed as user miadmin.
 *
 * BUILD INSTRUCTIONS
 *
 *     OSF1:     cc -I$MI_HOME/h -c do_unix.c
 *               ld -shared -expect_unresolved '*' -o do_unix.so do_unix.o
 *
 *     chmod a+x do_unix.so
 *
 * DATABASE CREATE
 *
 *      create function do_unix (text) returns setof(text)
 *      as external name '/FULLPATH/do_unix.so(do_unix)' language C;
 *
 *      create type unix_t (unix_results text);
 *
 *      create function unix (text)
 *      returns setof(unix_t)
 *      as select unix_results from do_unix($1) unix_results;
 *
 * SAMPLE USAGE
 *
 *      % msql template1 -w0
 *
 *      * select * from unix ('uname -a');
 *      ----------------------------
 *      |unix_results              |
 *      ----------------------------
 *      |OSF1 mighty V1.3 111 alpha|
 *      ----------------------------
 *      one row selected
 *      
 *      * select * from unix ('who');
 *      -----------------------------------------------------------------
 *      |unix_results                                                   |
 *      -----------------------------------------------------------------
 *      |jta         :0           Oct 06 08:14                          |
 *      |miadmin     ttyp5        Oct 06 09:18          (mighty.sdsc.edu)|
 *      -----------------------------------------------------------------
 *      2 rows selected
 *
 * $Header: /usr/local/devel/montage/samples/functions/RCS/do_unix.c,v 1.1 1994/10/06 16:27:13 jta Exp $
 */

#include "mi.h"
#include <string.h>
#include <stdio.h>

typedef struct unixstate {
     MI_CONNECTION  *conn;
     FILE           *strm;
} UnixState;

mi_text * do_unix ARGS(( mi_text *command, MI_FPARAM *fParam));

mi_text *
do_unix(str, fParam)
mi_text    *str;
MI_FPARAM  *fParam;
{

     mi_text   *retval;
     char      *r = "do_unix",
               *command,
               msg_buf[100],
               result[256];

     UnixState *unixState;
     FILE      *popen();

     switch(MI_FP_REQUEST(fParam))
     {
          case SET_INIT:
               unixState = (UnixState *) mi_alloc(sizeof(UnixState));
               MI_FP_SETFUNCSTATE(fParam, (void *) unixState);
               mi_set_mem_duration(unixState, PER_COMMAND);
               if(MI_FP_ARGISNULL(fParam, 0)) 
               {    MI_FP_SETRETURNISNULL(fParam, MI_TRUE);
                    break;
               }

               if ((unixState->conn = mi_open(NULL, NULL, NULL)) 
                    == (MI_CONNECTION *)NULL) 
               {    sprintf(msg_buf, "%s: could not get illustra connection",r);
                    mi_db_error_raise(unixState->conn, MI_EXCEPTION, msg_buf);
               }

               command = mi_text_to_string(str);

               /* execute the command.... */
               if((unixState->strm = popen(command, "r")) == NULL)
               {    sprintf(msg_buf, "popen failed");
                    mi_db_error_raise(unixState->conn, MI_MESSAGE, msg_buf);
               }
               break;
          case SET_RETONE:
               unixState = (UnixState *) MI_FP_FUNCSTATE(fParam);
               if(fgets(result, sizeof(result), unixState->strm) == NULL) 
               {    MI_FP_SETISDONE(fParam, MI_TRUE);
                    break;
               }

               if(result[strlen(result)-1] == '\n') /* Get rid of newline */
                   result[strlen(result)-1] = '\0';

               retval = mi_string_to_text(result);
               return(retval);
          case SET_END:
               unixState = (UnixState *) MI_FP_FUNCSTATE(fParam);
               pclose(unixState->strm);
               if (mi_close(unixState->conn) == MI_ERROR) 
               {    sprintf(msg_buf, "%s: could not close %s connection", r);
                    mi_db_error_raise(unixState->conn, MI_MESSAGE, msg_buf);
               }
               mi_free(unixState);
               break;
     }
}