Problem with a package ora_pipe_io

From: X <X_at_X.PT>
Date: 1997/09/30
Message-ID: <01bccdb6$94c483e0$8f61a8c0_at_wspc2883>

I'm trying to use the following oracle package to execute unix commands from a PC client in forms 4.5, but it doesn't work because form 4.5 requires that the second parameter of load_library procedure be a value diferent of null.

Can anyone help, or otherwise tell me the best way to execute unix commands from de PC client.

thanks

Luis M. Santos (l-miguel-santos_at_telecom.pt)

NAME
ora_pipe_io_spec.sql - Specification for access to Unix Pipe mechanism

DESCRIPTION
Demonstration of how to use the ORA_FFI Package to provide access to the

Unix Pipe C functions.
PUBLIC FUNCTION(S)

     popen    - Open the Pipe command 
     get_line - Get a line of Text from a Pipe 
     put_line - Put a line of Text into a Pipe 
     pclose   - Close the Pipe 
     is_open  - Determine whether the Pipe descriptor is open.

NOTES

     In Order to use these routines you could write  the following 
     PL/SQL Code: 
 
        -- Example of Calls to ora_pipe_io functions 
        DECLARE 
            stream ora_pipe_io.PIPE; 
            buffer VARCHAR2(240); 
        BEGIN 
            stream := ora_pipe_io.popen('ls -l', ora_pipe_io.READ_MODE); 
 
            loop 
                exit when not ora_pipe_io.get_line(stream, buffer, 240); 
                :directory.file := buffer; 
                down; 
            end loop; 
     
            ora_pipe_io.pclose(stream); 
        END;

MODIFIED (MM/DD/YY)
smclark 08/05/94 - Creation
*/

PACKAGE ora_pipe_io is

Arguments to popen. */ READ_MODE constant VARCHAR2(1) := 'r'; WRITE_MODE constant VARCHAR2(1) := 'w';

    /* ------------- TYPE PIPE ----------- */ 
    /*

Public Type PIPE - Handle to a Un*x pipe
**
Do not modify the private members of this type */ TYPE PIPE is RECORD (file_handle ORA_FFI.POINTERTYPE, is_open boolean, read_write_mode VARCHAR2(1));

    /* ------------ FUNCTION POPEN ----------- */ 
    /*

Function POPEN -- Open a Un*x pipe command
**
Given a Unix command to execute and a Pipe read/write mode in which
to execute the instruction this Function will execute the Command
and return a handle, of type PIPE, to the resulting Input/Output
stream.
**
The command to be executed is limited to 1024 characters. */ FUNCTION popen(command in VARCHAR2, ctype in VARCHAR2) RETURN PIPE;

    /* ------------ PROCEDURE PCLOSE ----------- */ 
    /*

Procedure PCLOSE -- Close a pipe
**
Close a previously opened pipe.
**
Raises a VALUE_ERROR exception if incorrect arguments are passed. */ PROCEDURE pclose(stream in out PIPE);

    /* ------------ FUNCTION GET_LINE ----------- */ 
    /*

Function GET_LINE
-- Get a line of text into a buffer from the read mode pipe.
**
Get a line of text from a previously opened pipe.
**
Raises a VALUE_ERROR exception if incorrect arguments are passed.
For example
if you pass a pipe which has never been opened (using popen) */ FUNCTION get_line(stream in out PIPE, s in out VARCHAR2, n in PLS_INTEGER) RETURN BOOLEAN;

    /* ------------ PROCEDURE PUT_LINE ----------- */ 
    /*

Procedure PUT_LINE -- Put a line of text into a a write mode pipe.
**
Put a line of text into a previously opened pipe.
**
Raises a VALUE_ERROR exception if incorrect arguments are passed.
For example
if you pass a pipe which has never been opened (using popen)
**
The Internal buffer for the string to write is limited to 2048 bytes

*/
PROCEDURE put_line(stream in out PIPE,

                       s in VARCHAR2); 
 
 
    /* ------------ FUNCTION IS_OPEN ----------- */ 
    /*

Function IS_OPEN -- Determines whether a pipe is open.
**
Returns TRUE if the pipe is open, FALSE if the pipe is closed. */ FUNCTION is_open(stream in PIPE) RETURN BOOLEAN; END;

/* ora_pipe_io_body.sql - Body of Package for access to Unix Pipe mechanism

DESCRIPTION
Demonstration of how to use the ORA_FFI Package to provide access to the

Unix Pipe C functions.
PUBLIC FUNCTION(S)

     popen    - Open the Pipe command 
     get_line - Get a line of Text from a Pipe 
     put_line - Put a line of Text into a Pipe 
     pclose   - Close the Pipe 
     is_open  - Determine whether the Pipe descriptor is open. 
   PRIVATE FUNCTION(S) 
     icd_popen, icd_fgets, icd_fputs, icd_pclose

   NOTES
   MODIFIED (MM/DD/YY)
    smclark 11/02/94 - Modified for production release changes to ORA_FFI.
    smclark 08/05/94 - Creation
*/

 PACKAGE BODY ora_pipe_io is 
    lh_libc   ora_ffi.libHandleType; 
    fh_popen  ora_ffi.funcHandleType; 
    fh_pclose ora_ffi.funcHandleType; 
    fh_fgets  ora_ffi.funcHandleType; 
    fh_fputs  ora_ffi.funcHandleType; 
 
    /* ------------ FUNCTION ICD_POPEN ----------- */ 
    /*

Function ICD_POPEN -- Interface routine to C function popen
**
This function acts as the interface to the popen function in
libc. */ FUNCTION icd_popen(funcHandle in ora_ffi.funcHandleType, command in out VARCHAR2, ctype in out VARCHAR2) return ORA_FFI.POINTERTYPE;

pragma interface(c, icd_popen, 11265);

    /* ------------ PROCEDURE ICD_PCLOSE ----------- */ 
    /*

Function ICD_PCLOSE -- Interface routine to C function pclose
**
This function acts as the interface to the pclose function in
libc. */ PROCEDURE icd_pclose(funcHandle in ora_ffi.funcHandleType, stream in out ORA_FFI.POINTERTYPE);

pragma interface(c, icd_pclose, 11265);

    /* ------------ FUNCTION ICD_FGETS ----------- */ 
    /*

Function ICD_FGETS -- Interface routine to C function fgets
**
This function acts as the interface to the fgets function in
libc. */ FUNCTION icd_fgets(funcHandle in ora_ffi.funcHandleType, s in out VARCHAR2, n in PLS_INTEGER, stream in out ORA_FFI.POINTERTYPE) RETURN ORA_FFI.POINTERTYPE;

pragma interface(c, icd_fgets, 11265);

    /* ------------ FUNCTION ICD_FPUTS ----------- */ 
    /*

Function ICD_FPUTS -- Interface routine to C function fputs
**
This function acts as the interface to the fputs function in
libc. */ PROCEDURE icd_fputs(funcHandle in ora_ffi.funcHandleType, s in out VARCHAR2, stream in out ORA_FFI.POINTERTYPE);

pragma interface(c, icd_fputs, 11265);

    /* ------------ FUNCTION POPEN ----------- */ 
    /*

Function POPEN -- Open a Un*x pipe command */ FUNCTION popen(command in VARCHAR2, ctype in VARCHAR2) RETURN PIPE is

        /* 
        ** Take a copy of the arguments because we need to pass them 
        ** IN OUT to icd_popen, but we really don't want people to have 
        ** to call our routines in the same way. 
        */ 
        cmd varchar2(1024) := command; 
        cmode varchar2(1) := ctype; 
 
        stream PIPE; 
    BEGIN 
        if (cmode not in (READ_MODE, WRITE_MODE)) 
           or (cmode is NULL) 
           or (cmd is NULL) 
        then 
            raise VALUE_ERROR; 
        end if; 
 
        stream.file_handle := icd_popen(fh_popen, cmd, cmode); 
        stream.is_open := TRUE; 
        stream.read_write_mode := ctype; 
        return(stream); 
    END popen; 
     
 
    /* ------------ PROCEDURE PCLOSE ----------- */

Procedure PCLOSE -- Close a pipe */ PROCEDURE pclose(stream in out PIPE) is BEGIN icd_pclose(fh_pclose, stream.file_handle); stream.is_open := FALSE; END pclose;

    /* ------------ FUNCTION GET_LINE ----------- */ 
    /*

Function GET_LINE -- Get a line of text into a buffer
from the read mode pipe. */ FUNCTION get_line(stream in out PIPE, s in out VARCHAR2, n in PLS_INTEGER) RETURN BOOLEAN is buffer ORA_FFI.POINTERTYPE; BEGIN if (n <= 0) or (stream.is_open = FALSE) or (stream.is_open is NULL) or (stream.read_write_mode <> READ_MODE) then raise VALUE_ERROR; end if;

        /* 
        ** Initialise the Buffer area to reserve the correct amount of
space. 
        */ 
 
        s := rpad(' ', n); 
 
        buffer := icd_fgets(fh_fgets, s, n, stream.file_handle); 
 
        /* 
        ** Determine whether a NULL pointer was returned. 
        */ 
        return (ora_ffi.is_null_ptr(buffer) = FALSE);

END get_line;

    /* ------------ PROCEDURE PUT_LINE ----------- */ 
    /*

Procedure PUT_LINE -- Put a line of text into a a write mode pipe. */ PROCEDURE put_line(stream in out PIPE, s in VARCHAR2) is buffer varchar2(2048) := s; BEGIN if (stream.is_open = FALSE) or (stream.is_open is NULL) or (stream.read_write_mode <> WRITE_MODE) then raise VALUE_ERROR; end if;

        icd_fputs(fh_fputs, buffer, stream.file_handle); 
        buffer := chr(10); 
        icd_fputs(fh_fputs, buffer, stream.file_handle);

END put_line;

    /* ------------ FUNCTION IS_OPEN ----------- */ 
    /*

Function IS_OPEN -- Determines whether a pipe is open. */ FUNCTION is_open(stream in PIPE) RETURN BOOLEAN is BEGIN return(stream.is_open); END is_open;

BEGIN
/*

Declare a library handle as libc. (Internal so NULL,NULL) */ lh_libc := ora_ffi.load_library(NULL, NULL); if ora_ffi.is_null_ptr(lh_libc) then raise VALUE_ERROR; end if;

Register the popen function, it's return type and arguments. */ fh_popen := ora_ffi.register_function(lh_libc, 'popen'); if ora_ffi.is_null_ptr(fh_popen) then raise VALUE_ERROR; end if; ora_ffi.register_return(fh_popen, ORA_FFI.C_DVOID_PTR); ora_ffi.register_parameter(fh_popen, ORA_FFI.C_CHAR_PTR); ora_ffi.register_parameter(fh_popen, ORA_FFI.C_CHAR_PTR);

Register the pclose function, it's return type and arguments. */ fh_pclose := ora_ffi.register_function(lh_libc, 'pclose'); if ora_ffi.is_null_ptr(fh_pclose) then raise VALUE_ERROR; end if; ora_ffi.register_return(fh_pclose, ORA_FFI.C_VOID); ora_ffi.register_parameter(fh_pclose, ORA_FFI.C_DVOID_PTR);

Register the fgets function, it's return type and arguments. */ fh_fgets := ora_ffi.register_function(lh_libc, 'fgets'); if ora_ffi.is_null_ptr(fh_fgets) then raise VALUE_ERROR; end if; ora_ffi.register_return(fh_fgets, ORA_FFI.C_DVOID_PTR); ora_ffi.register_parameter(fh_fgets, ORA_FFI.C_CHAR_PTR); ora_ffi.register_parameter(fh_fgets, ORA_FFI.C_INT); ora_ffi.register_parameter(fh_fgets, ORA_FFI.C_DVOID_PTR);

Register the fputs function, it's return type and arguments. */ fh_fputs := ora_ffi.register_function(lh_libc, 'fputs'); if ora_ffi.is_null_ptr(fh_fputs) then raise VALUE_ERROR; end if; ora_ffi.register_return(fh_fputs, ORA_FFI.C_VOID); ora_ffi.register_parameter(fh_fputs, ORA_FFI.C_CHAR_PTR); ora_ffi.register_parameter(fh_fputs, ORA_FFI.C_DVOID_PTR);

END ora_pipe_io; Received on Tue Sep 30 1997 - 00:00:00 CEST

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