PAM-Linux in FPC
lazarus / 32-Linux

----------------------------------------------------------------------
RedCat · 2022-02-19 05:51

Hi all!
I needed to use PAM-Linux in my project, does the FPC have ported
header files (pam_appl, pam_client, etc.). I tried first to find these
files, but I couldn't, then I tried to translate it myself, but there
are a few things I don't understand. All I need from PAM is to verify
that the username and password are entered correctly.

----------------------------------------------------------------------
Thaddy · 2022-02-19 10:48

They are really plain C header files, so can be 99% translated with
h2pas and h2paspp.
Just make sure the calling conventions are correct.

----------------------------------------------------------------------
RedCat · 2022-02-19 11:40

h2pas produces several syntax errors, h2paspp translates almost
nothing, and I can't translate this structure by hand:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i typedef
struct pam_handle pam_handle_t;the problem is that the pam_handle
description is in the pam_private.h file, which is not in the
libpam0g-dev package, and the structure has a comment:
Quote/* This is a blind structure; users aren't allowed to see inside
a
  * pam_handle_t, so we don't define struct pam_handle here. This is
  * defined in a file private to the PAM library. (i.e., it's private
  * to PAM service modules, too!) */
but if I translate this structure like this:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
typepam_handle_t = pam_handle; the compiler will give an error saying
that it doesn't know anything about pam_handle

----------------------------------------------------------------------
Thaddy · 2022-02-19 11:46

FPC supports such opaque data in system:
https://www.freepascal.org/docs-html/rtl/system/topaquedata.html
May be you need to tweak some settings in the headers, but AFICS there
is not really a problem.

----------------------------------------------------------------------
RedCat · 2022-02-19 11:50

Thanks I'll try it now

----------------------------------------------------------------------
MarkMLl · 2022-02-19 12:14

Let us know how you get on, since header conversion- and making sure
that extra libraries work- is of universal interest.

MarkMLl

----------------------------------------------------------------------
RedCat · 2022-02-19 13:14

I tried to translate so far only the main functions I need, it turned
out badly, I have very superficial knowledge of C syntax, I did this:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i unit
pam_types;{$IFDEF FPC}  {$mode objfpc}{$H+}{$ENDIF} interface  uses 
Classes, SysUtils; const  {$IFDEF FPC}    {$IFDEF LINUX}      libPAM =
'libpam.so';    {$ENDIF}   {$ENDIF}typepam_handle_t=recordend; type 
pam_message = record      msg_style : long      msg : ^char;   
end; type  pam_response = record      resp : ^char;      resp_retcode
: longint;    end; typeppam_message = ^pam_message;ppam_response =
^pam_response;pppam_message = ^ppam_message;ppam_response =
^ppam_response;    typepam_conv_t = record          conv : function
(num_msg:longint; msg:PPpam_message; resp:PPpam_response;
appdata_ptr:pointer):longint;cdecl;          appdata_ptr : pointer;  
    end; typeppam_handle_t = ^pam_handle_t;PPpam_handle_t =
^Ppam_handle_t;   typeppam_conv = pam_conv_t; function pam_start(const
service_name : PByte; const user : PByte; const pam_conversation :
Ppam_conv; pamh : PPpam_handle_t):integer; cdecl; external
libPAM;function pam_end(pamh :
PPpam_handle_t;pam_status:integer):integer; cdecl; external
libPAM;implementationend. I call like this:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i varres:inte
ger;pam_hannn:Ppam_handle_t; pam_cconv:pam_conv_t;beginres:=pam_start(
Pbyte(PChar('check')),Pbyte(Pchar('redcat')),pam_cconv,@pam_hannn);Mem
o1.Lines.Add(IntToStr(res));end; and received in response when the
application was launched
External: SIGSEGV (Accesss violation)

----------------------------------------------------------------------
MarkMLl · 2022-02-19 13:32

Use h2pas, as somebody has said already. That will result in a
separate file into which the command line will be embedded so that
people can duplicate what you're doing.

https://www.freepascal.org/tools/h2pas.html
https://wiki.freepascal.org/H2Pas
https://wiki.freepascal.org/Creating_bindings_for_C_libraries
https://wiki.freepascal.org/Common_problems_when_converting_C_header_f
iles

MarkMLl

----------------------------------------------------------------------
RedCat · 2022-02-19 13:55

Maybe I'm doing something wrong, but the pam_appl.h h2pas file does
not want to translate at all, this is how the original file looks
like:
Code: Text  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i /* *
<security/pam_appl.h> * * This header file collects definitions for
the PAM API --- that is, * public interface between the PAM library
and an application program * that wishes to use it. * * Note, the
copyright information is at end of file. */ #ifndef
_SECURITY_PAM_APPL_H#define _SECURITY_PAM_APPL_H #ifdef
__cplusplusextern "C" {#endif #include <security/_pam_types.h>      /*
Linux-PAM common defined types */ /* -------------- The Linux-PAM
Framework layer API ------------- */ extern int
PAM_NONNULL((1,3,4))pam_start(const char *service_name, const char
*user,          const struct pam_conv *pam_conversation,         
pam_handle_t **pamh); extern int PAM_NONNULL((1))pam_end(pam_handle_t
*pamh, int pam_status); /* Authentication API's */ extern int
PAM_NONNULL((1))pam_authenticate(pam_handle_t *pamh, int
flags); extern int PAM_NONNULL((1))pam_setcred(pam_handle_t *pamh, int
flags); /* Account Management API's */ extern int
PAM_NONNULL((1))pam_acct_mgmt(pam_handle_t *pamh, int flags); /*
Session Management API's */ extern int
PAM_NONNULL((1))pam_open_session(pam_handle_t *pamh, int
flags); extern int PAM_NONNULL((1))pam_close_session(pam_handle_t
*pamh, int flags); /* Password Management API's */ extern int
PAM_NONNULL((1))pam_chauthtok(pam_handle_t *pamh, int flags);  /* take
care of any compatibility issues */#include
<security/_pam_compat.h> #ifdef __cplusplus}#endif /* * Copyright
Theodore Ts'o, 1996.  All rights reserved. * * Redistribution and use
in source and binary forms, with or without * modification, are
permitted provided that the following conditions * are met: * 1.
Redistributions of source code must retain the above copyright *  
 notice, and the entire permission notice in its entirety, *  
 including the disclaimer of warranties. * 2. Redistributions in
binary form must reproduce the above copyright *    notice, this list
of conditions and the following disclaimer in the *    documentation
and/or other materials provided with the distribution. * 3. The name
of the author may not be used to endorse or promote *    products
derived from this software without specific prior *    written
permission. * * ALTERNATIVELY, this product may be distributed under
the terms of * the GNU Public License, in which case the provisions of
the GPL are * required INSTEAD OF the above restrictions.  (This
clause is * necessary due to a potential bad interaction between the
GPL and * the restrictions contained in a BSD-style copyright.) * *
THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED *
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED.
 IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, * INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING,
BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR * SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED * OF THE
POSSIBILITY OF SUCH DAMAGE. */ #endif /* _SECURITY_PAM_APPL_H */ and
after processing h2pas:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i unit
pam_appl;interface {  Automatically converted by H2Pas 1.0.0 from
D:\Projects\Lazarus\RTS_Configurator\LibPAM\pam_appl.h  The following
command line parameters were used:   
D:\Projects\Lazarus\RTS_Configurator\LibPAM\pam_appl.h} {$IFDEF
FPC}{$PACKRECORDS C}{$ENDIF}    {   * <security/pam_appl.h>   *   *
This header file collects definitions for the PAM API --- that is,   *
public interface between the PAM library and an application program 
 * that wishes to use it.   *   * Note, the copyright information is
at end of file.    }{$ifndef _SECURITY_PAM_APPL_H}{$define
_SECURITY_PAM_APPL_H}  { C++ extern C conditionnal removed }{$include
<security/_pam_types.h>      /* Linux-PAM common defined types */}  {
-------------- The Linux-PAM Framework layer API -------------  }(*
error extern int PAM_NONNULL((1,3,4))(* error extern int
PAM_NONNULL((1,3,4))(* error extern int PAM_NONNULL((1,3,4))(* error
pam_start(const char *service_name, const char *user,(* error        
 const struct pam_conv *pam_conversation,(* error          
pam_handle_t **pamh); in declarator_list *) in declarator_list *) in
declarator_list *) in declarator_list *) in declarator_list *) in
declarator_list *)(* error extern int PAM_NONNULL((1))(* error
pam_end(pam_handle_t *pamh, int pam_status); in declarator_list *) in
declarator_list *)  { Authentication API's  }(* error extern int
PAM_NONNULL((1))(* error pam_authenticate(pam_handle_t *pamh, int
flags); in declarator_list *) in declarator_list *)(* error extern int
PAM_NONNULL((1))(* error pam_setcred(pam_handle_t *pamh, int
flags); in declarator_list *) in declarator_list *)  { Account
Management API's  }(* error extern int PAM_NONNULL((1))(* error
pam_acct_mgmt(pam_handle_t *pamh, int flags); in declarator_list *) in
declarator_list *)  { Session Management API's  }(* error extern int
PAM_NONNULL((1))(* error pam_open_session(pam_handle_t *pamh, int
flags); in declarator_list *) in declarator_list *)(* error extern int
PAM_NONNULL((1))(* error pam_close_session(pam_handle_t *pamh, int
flags); in declarator_list *) in declarator_list *)  { Password
Management API's  }(* error extern int PAM_NONNULL((1))(* error
pam_chauthtok(pam_handle_t *pamh, int flags); in declarator_list *) in
declarator_list *)  { take care of any compatibility issues
 }{$include <security/_pam_compat.h>}{ C++ end of extern C
conditionnal removed }  {   * Copyright Theodore Ts'o, 1996.  All
rights reserved.   *   * Redistribution and use in source and binary
forms, with or without   * modification, are permitted provided that
the following conditions   * are met:   * 1. Redistributions of source
code must retain the above copyright   *    notice, and the entire
permission notice in its entirety,   *    including the disclaimer of
warranties.   * 2. Redistributions in binary form must reproduce the
above copyright   *    notice, this list of conditions and the
following disclaimer in the   *    documentation and/or other
materials provided with the distribution.   * 3. The name of the
author may not be used to endorse or promote   *    products derived
from this software without specific prior   *    written permission. 
 *   * ALTERNATIVELY, this product may be distributed under the terms
of   * the GNU Public License, in which case the provisions of the GPL
are   * required INSTEAD OF the above restrictions.  (This clause is 
 * necessary due to a potential bad interaction between the GPL and 
 * the restrictions contained in a BSD-style copyright.)   *   * THIS
SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED   *
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES   *
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE   *
DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, 
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT,   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
OTHERWISE)   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
EVEN IF ADVISED   * OF THE POSSIBILITY OF SUCH DAMAGE.    }{$endif}  {
_SECURITY_PAM_APPL_H  } implementation  end.

----------------------------------------------------------------------
RedCat · 2022-02-19 14:05

And if you run from the IDE, lazarus first freezes, and then gives an
error: QuoteTRegExpr exec: empty input string

----------------------------------------------------------------------
MarkMLl · 2022-02-19 14:14

Quote from: RedCat on February 19, 2022, 02:55:21 pmMaybe I'm doing
something wrong, but the pam_appl.h h2pas file does not want to
translate at all, this is how the original file looks like:

OK, I'm not the local expert but I'm here while the other guys have
hopefully got more fun things to do :-)

First, pam_appl.h isn't on my (Debian x86_64) system: where did you
get it?

MarkMLl

----------------------------------------------------------------------
RedCat · 2022-02-19 14:19

There is a contact! The error was that I declared one of the
parameters
type
ppam_conv = pam_conv_t;
And should have
type
ppam_conv = ^pam_conv_t;
Now there is no Access Violation and there is a return code from
LibPAM
Code 4 is:
  { system error }
     PAM_SYSTEM_ERR = 4;

----------------------------------------------------------------------
RedCat · 2022-02-19 14:41

Have code 0
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i unit
pam_types;{$IFDEF FPC}  {$mode objfpc}{$H+}{$ENDIF} interface  uses 
Classes, SysUtils; const  {$IFDEF FPC}    {$IFDEF LINUX}      libPAM =
'libpam.so';    {$ENDIF}   {$ENDIF} const  {$IFDEF FPC}    {$IFDEF
LINUX}      libPAM_misc = 'libpam_misc.so';    {$ENDIF} 
 {$ENDIF}  const    __LINUX_PAM__ = 1;    __LINUX_PAM_MINOR__ = 0;  {
----------------- The Linux-PAM return values ------------------  }  {
Successful function return  }    PAM_SUCCESS = 0;  { dlopen() failure
when dynamically  }    PAM_OPEN_ERR = 1;  { loading a service module
 }  { Symbol not found  }    PAM_SYMBOL_ERR = 2;  { Error in service
module  }    PAM_SERVICE_ERR = 3;  { System error  }    PAM_SYSTEM_ERR
= 4;  { Memory buffer error  }    PAM_BUF_ERR = 5;  { Permission
denied  }    PAM_PERM_DENIED = 6;  { Authentication failure  }   
PAM_AUTH_ERR = 7;  { Can not access authentication data  }   
PAM_CRED_INSUFFICIENT = 8;  { due to insufficient credentials  }  {
Underlying authentication service  }    PAM_AUTHINFO_UNAVAIL = 9;  {
can not retrieve authentication  }  { information   }  { User not
known to the underlying  }    PAM_USER_UNKNOWN = 10;  { authenticaiton
module  }  { An authentication service has  }    PAM_MAXTRIES = 11;  {
maintained a retry count which has  }  { been reached.  No further
retries  }  { should be attempted  }  { New authentication token
required.  }    PAM_NEW_AUTHTOK_REQD = 12;  { This is normally
returned if the  }  { machine security policies require  }  { that the
password should be changed  }  { beccause the password is NULL or it
 }  { has aged  }  { User account has expired  }    PAM_ACCT_EXPIRED =
13;  { Can not make/remove an entry for  }    PAM_SESSION_ERR = 14;  {
the specified session  }  { Underlying authentication service  }   
PAM_CRED_UNAVAIL = 15;  { can not retrieve user credentials  }  {
unavailable  }  { User credentials expired  }    PAM_CRED_EXPIRED =
16;  { Failure setting user credentials  }    PAM_CRED_ERR = 17;  { No
module specific data is present  }    PAM_NO_MODULE_DATA = 18;  {
Conversation error  }    PAM_CONV_ERR = 19;  { Authentication token
manipulation error  }    PAM_AUTHTOK_ERR = 20;  { Authentication
information  }    PAM_AUTHTOK_RECOVERY_ERR = 21;  { cannot be
recovered  }  { Authentication token lock busy  }   
PAM_AUTHTOK_LOCK_BUSY = 22;  { Authentication token aging disabled  } 
  PAM_AUTHTOK_DISABLE_AGING = 23;  { Preliminary check by password
service  }    PAM_TRY_AGAIN = 24;  { Ignore underlying account module
 }    PAM_IGNORE = 25;  { regardless of whether the control  }  { flag
is required, optional, or sufficient  }  { Critical error (?module
fail now request)  }    PAM_ABORT = 26;  { user's authentication token
has expired  }    PAM_AUTHTOK_EXPIRED = 27;  { module is not known  } 
  PAM_MODULE_UNKNOWN = 28;  { Bad item passed to pam_*_item()  }   
PAM_BAD_ITEM = 29;  { conversation function is event driven          
                         and data is not available yet  }   
PAM_CONV_AGAIN = 30;  { please call this function again to           
                      complete authentication stack. Before          
                       calling again, verify that conversation       
                          is completed  }    PAM_INCOMPLETE = 31;  { 
 * Add new #define's here - take care to also extend the libpam code: 
 * pam_strerror() and "libpam/pam_tokens.h" .    }  { this is the
number of return values  }    _PAM_RETURN_VALUES = 32;  {
---------------------- The Linux-PAM flags --------------------  }  {
Authentication service should not generate any messages  }   
PAM_SILENT = $8000;  { Note: these flags are used by
pam_authenticate,_secondary()  }  { The authentication service should
return PAM_AUTH_ERROR if the   * user has a null authentication token
 }    PAM_DISALLOW_NULL_AUTHTOK = $0001;  { Note: these flags are used
for pam_setcred()  }  { Set user credentials for an authentication
service  }    PAM_ESTABLISH_CRED = $0002;  { Delete user credentials
associated with an authentication service  }    PAM_DELETE_CRED =
$0004;  { Reinitialize user credentials  }    PAM_REINITIALIZE_CRED =
$0008;  { Extend lifetime of user credentials  }    PAM_REFRESH_CRED =
$0010;  { Note: these flags are used by pam_chauthtok  }  { The
password service should only update those passwords that have   *
aged.  If this flag is not passed, the password service should   *
update all passwords.  }    PAM_CHANGE_EXPIRED_AUTHTOK = $0020;  {
------------------ The Linux-PAM item types -------------------  }  {
These defines are used by pam_set_item() and pam_get_item().   
 Please check the spec which are allowed for use by applications   
 and which are only allowed for use by modules.  }  { The service name
 }    PAM_SERVICE = 1;  { The user name  }    PAM_USER = 2;  { The tty
name  }    PAM_TTY = 3;  { The remote host name  }    PAM_RHOST = 4; 
{ The pam_conv structure  }    PAM_CONV = 5;  { The authentication
token (password)  }    PAM_AUTHTOK = 6;  { The old authentication
token  }    PAM_OLDAUTHTOK = 7;  { The remote user name  }   
PAM_RUSER = 8;  { the prompt for getting a username  }   
PAM_USER_PROMPT = 9;  { Linux-PAM extensions  }  { app supplied
function to override failure                                   delays
 }    PAM_FAIL_DELAY = 10;  { X display name  }    PAM_XDISPLAY = 11; 
{ X server authentication data  }    PAM_XAUTHDATA = 12;  { The type
for pam_get_authtok  }    PAM_AUTHTOK_TYPE =
13; typepam_handle_t=recordend; type  pam_message = record     
msg_style : longint;      msg : ^char;    end; type  pam_response =
record      resp : ^char;      resp_retcode : longint;   
end; typePpam_message  = ^pam_message;Ppam_response  =
^pam_response;PPpam_message  = ^Ppam_message;PPpam_response  =
^Ppam_response;    typepam_conv_t = record          conv : function
(num_msg:longint; msg:PPpam_message; resp:PPpam_response;
appdata_ptr:pointer):longint;cdecl;          appdata_ptr : pointer;  
    end; typePpam_handle_t = ^pam_handle_t;PPpam_handle_t =
^Ppam_handle_t;   typePpam_conv = ^pam_conv_t; function
pam_start(const service_name : PByte; const user : PByte; const
pam_conversation : Ppam_conv; pamh : PPpam_handle_t):integer; cdecl;
external libPAM;function pam_end(pamh :
PPpam_handle_t;pam_status:integer):integer; cdecl; external
libPAM;function misc_conv(num_msg:longint; msg:PPpam_message;
resp:PPpam_response; appdata_ptr:pointer):longint; cdecl; external
libPAM_misc; implementationend. I call like this:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TForm1.Button1Click(Sender: TObject);varres:integer;pam_hannn:Ppam_han
dle_t;TestConv:pam_conv_t;beginTestConv.conv:=@misc_conv;TestConv.appd
ata_ptr:=nil;res:=pam_start(Pbyte(PChar('check')),Pbyte(Pchar('redcat'
)),@TestConv,@pam_hannn);Memo1.Lines.Add(IntToStr(res));end; end. As
functions are added, I will post pam_types.pas here

----------------------------------------------------------------------
RedCat · 2022-02-20 04:33

The first version of the translation of titles (Some functions have
not been tested, and some have not yet been translated). There is also
a console application for testing authentication, but until the
problem of redirecting the output of the password request by the
library to its application has been resolved, this prevents the
library from being used in the GUI application
https://github.com/RedCatN1/LibPAM_Pascal-headers

----------------------------------------------------------------------
MarkMLl · 2022-02-20 08:39

Quote from: RedCat on February 20, 2022, 05:33:18 amuntil the problem
of redirecting the output of the password request by the library to
its application has been resolved, this prevents the library from
being used in the GUI application

That's likely to be a problem. Research the way that e.g. Subversion
does it: IIRC there's a daemon involved which pops up a dialog(u)e.

I've previously looked at this to some extent in the context of
getting the IDE to set POSIX capabilities etc. post-compilation. I
can't remember the details, the patch is somewhere in whatever's taken
over from Mantis.

MarkMLl

----------------------------------------------------------------------
RedCat · 2022-02-20 09:55

There is an easier way to write my own conversion implementation, I'm
trying now, I'm confused about pointers, who knows C well please help
me, I do this:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i function
conversation(num_msg:longint; msg:PPpam_message; resp:PPpam_response;
appdata_ptr:pointer):longint;cdecl;vari:longint;passstr:string;m:ppam_
message;r:ppam_response;begin    appdata_ptr:=nil;    { check the
count of message }    if (num_msg <= 0 ) or (num_msg >=
PAM_MAX_MSG_SIZE) then    begin        writeln('invalid num_msg
'+inttostr(num_msg));        result:=PAM_CONV_ERR;    end;    { alloc
memory for response }    r:=CAlloc(num_msg,SizeOf(pam_response));   
if r=nil then    begin      writeln('bad alloc ');     
result:=PAM_BUF_ERR;    end;    { response for message }    for i:= 0
to num_msg-1 do    Begin        m:=msg[i];      if m^.msg_style =
PAM_PROMPT_ECHO_OFF then          begin            
writeln('MyMessage: '+Pchar(m^.msg));            readln(passstr);    
      r^.resp:=Pchar(passstr);            r^.resp_retcode:= 0;       
   resp:=@r[i];            break;         end;    end;   
result:=PAM_SUCCESS;end; And so it is done in the example to the
source codes of LibPAM:
Code: C  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i static int
conversation(int num_msg, const struct pam_message **msg, struct
pam_response **resp, void *appdata_ptr){    (void)(appdata_ptr);   
int i;     /* check the count of message */    if (num_msg <= 0 ||
num_msg >= PAM_MAX_MSG_SIZE)    {        fprintf(stderr, "invalid
num_msg(%d)\n", num_msg);        return PAM_CONV_ERR;    }     /*
alloc memory for response */    if ((resp[0] = malloc(num_msg *
sizeof(struct pam_response))) == NULL)    {        fprintf(stderr,
"bad alloc\n");        return PAM_BUF_ERR;    }     /* response for
message */    for (i = 0; i < num_msg; i++)    {        const struct
pam_message *m = *msg + i;        struct pam_response *r = *resp + i; 
      r->resp_retcode = 0;    /* currently un-used, zero expected */ 
     switch (m->msg_style)        {        case PAM_PROMPT_ECHO_OFF: 
/* get the input with echo off, like the password */           
printf("%s", m->msg);            echoOffStdin();            r->resp =
readline();            echoOnStdin();            printf("\n");       
   break;         case PAM_PROMPT_ECHO_ON:    /* get the input with
echo on, like the username */            printf("%s", m->msg);       
   r->resp = readline();            break;         case PAM_TEXT_INFO:
        /* normal info */            printf("%s\n", m->msg);         
 break;         case PAM_ERROR_MSG:         /* error info */         
 fprintf(stderr, "%s\n", m->msg);            break;         default: 
         fprintf(stderr, "unexpected msg_style: %d\n", m->msg_style); 
          break;        }    }    return PAM_SUCCESS;} I get Access
Violation, or with other parameters error free unknown pointer, or
else malloc corrupted top size , and with this code, the authorization
function returns code 7 just a few pointers to pointers completely
confused me

----------------------------------------------------------------------
RedCat · 2022-02-20 10:43

I especially don't understand these lines:
Code: C  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i resp[0] =
malloc(num_msg * sizeof(struct pam_response)) here it is not clear to
me whether resp[0] is the same as resp[0] in FPC? If struct
pam_response **resp and in fpc resp:PPpam_response?
Code: C  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i        
 const struct pam_message *m = *msg + i;         struct pam_response
*r = *resp + i;  And here, too, it is not entirely clear how the
assignment is obtained

----------------------------------------------------------------------
MarkMLl · 2022-02-20 11:40

You've still not said what package etc. you got the original files
from.

The first of those will depend on how you're defining the resp[]
array, but if I'm reading your example properly malloc() is allocating
a block of memory sufficient for the size of a response multiplied by
the number of responses and saving a pointer to the start (remember
the array/pointer duality in C).

I the second I /think/ the addition is incrementing by the size of the
message or response, i.e. is stepping on to the next element in the
array.

MarkMLl

----------------------------------------------------------------------
RedCat · 2022-02-20 12:28

Source files taken from here: https://github.com/linux-pam
Do I understand correctly that resp[0] = malloc(num_msg *
sizeof(struct pam_response)) is the same as resp[0]:= GetMem(num_msg *
sizeof(pam_response)) in fpc?
And what about the assignment of r to resp? and is it possible to
directly specify resp[0]^^. resp := Phar(pass )
I have a feeling that there is a confusion with addresses, since
resp:PPpam_response and the library reads the wrong thing, and I can’t
find out in any way what is really transferred to LibPAM with this
callback

----------------------------------------------------------------------
MarkMLl · 2022-02-20 13:09

No promises but I'll try to take a bit of a look later... particularly
if the I2C stuff I'm playing with continues in its intransigence. Note
however that I'm not the most experienced guy around at doing this, so
trust almost anybody else's advice before mine :-)

I've seen where your h2pas commandline is noted. Have you checked that
the C variant of that project actually compiles and runs successfully
on your system? I've seen plenty of other projects where Github etc.
contained sources which didn't quite match the kernel and standard
libraries that the rest of the World assumed were "stable".

MarkMLl

----------------------------------------------------------------------
RedCat · 2022-02-20 14:35

No, to be honest, I have not tried to collect these sources, but what
has already been translated without my implementation of the
conversion function works fine, (meaning with the conversion function
from the pam_misc.so library) I understand that the problem is in
pointers and arrays, I know very little and I don’t know English well,
and as luck would have it, I didn’t find a description of my problem
in my language, for some reason I found a description in English.
description in attached
As far as I understand, I'm trying to work with a pointer to an array
of pointers

----------------------------------------------------------------------
RedCat · 2022-02-22 12:34

Updated header file and test project, now has its own function
CatConversion for transferring login and password to LibPAM
https://github.com/RedCatN1/LibPAM_Pascal-headers