BFD question

BFD question

[Bloch, Jack]

Can anyone help. I am writing an application that needs to read symbols from
an executable file.
I am running a stock SuSE 2.4.19 Kernel. I have libbfd version 2.12.90.0.15.

My code reads as follows :

bfd         *l_bfd          = NULL;
      char        *l_target	      = "elf32-i386";
      const char  *l_err          = NULL;
      long        l_storage       = 0;
      long        l_symnum	      = 0;
      long        l_ndx           = 0;
      int         l_dyn           = 0;
      int         l_flags         = 0;
      int         l_access        = (EXEC_P | HAS_SYMS);
      asymbol     **l_symbol      = NULL;
                         
      if (!p_file)
      { /* invalid file name */
         printf("INVALID FILE NAME FOR EXTRACT SYMBOLS !!!\n");
         return(-1); /* set error indicator */
      }   	
      printf("EXTRACTING SYMBOLS FOR FILE %s\n",p_file);
      
      /*****************/
      /* open the file */
      /*****************/ 
      
      if ((l_bfd = bfd_openr(p_file,l_target)) == NULL)
      { /* unable to open file */
       	l_err = bfd_errmsg(bfd_get_error ()); /* read BFD error */
         printf("ERROR %s OPENing FILE %s FOR SYMBOL EXTRACTION
!!!\n",l_err,p_file);
         return(-1); /* set error indicator */
      }
                 
      /***********************************/
      /* check the file format to ensure */
      /* an executable file.             */
      /***********************************/
      
      if (!bfd_check_format(l_bfd,bfd_object))
      { /* not an executable file */
         l_err = bfd_errmsg(bfd_get_error ()); /* read BFD error */
         printf("BFD ERROR %s VALIDATING EXECUTABLE SYMBOL FORMAT ON
%s\n",l_err,p_file);
         bfd_close(l_bfd); /* close file */
         return(-1); /* set error indicator */
      }     
      
      /*****************************************************/
      /* ensure that the given file has symbols associated */
      /* with it.                                          */
      /*****************************************************/
      
      l_flags = bfd_get_file_flags(l_bfd);
      if ((l_flags & l_access) == 0)
      { /* no symbols associated with this file */
         printf("NO SYMBOLIC INFORMATION FOUND FOR %s !!!\n",p_file);
         return(-1); /* set error indicator */
      }   	
      
      /******************************************************/
      /* determine the amount of memory needed to store the */
      /* program symbols. this can be static or dynamic     */
      /* storage.                                           */
      /******************************************************/
      
      l_storage = bfd_get_symtab_upper_bound(l_bfd);
      if (l_storage == 0);
      { /* static failed so try dynamic */
         printf("RETRIEVING STATIC STORAGE FAILED, TRYING DYNAMIC !!!\n");
         l_storage = bfd_get_dynamic_symtab_upper_bound(l_bfd);
         if (l_storage == 0);
         { /* cannot retrieve dynamic storage size */
            printf("FAILED TO RETRIEVE DYNAMIC STORAGE SIZE !!!\n");
            return(-1); /* set eror indicator */
         }
      }      
      return(0); /* set success indicator */

The call to bfd_get_file_flags returns a 0. The file is indeed an elf32-i386
target.


Please respond to jack.bloch@icn.siemens.com


Thanks in advance.

Re: BFD question

[Ian Lance Taylor]

"Bloch, Jack" <Jack.Bloch@icn.siemens.com> writes:

> The call to bfd_get_file_flags returns a 0. The file is indeed an elf32-i386
> target.

What does objdump -f return on the file?

Has the file perhaps been stripped?

Ian

RE: BFD question

[Bloch, Jack]

 Here is the output 


objdump -f Coregen

Coregen:     file format elf32-i386
architecture: i386, flags 0x00000112:
EXEC_P, HAS_SYMS, D_PAGED
start address 0x08048400


This looks good to me.

By the way, I forgot to show in my code listing that p_file is a char *
passed in as a parameter ans is set to "/usr/coretest/Coregen"

-----Original Message-----
From: Ian Lance Taylor
To: Bloch, Jack
Cc: 'gdb@sources.redhat.com'
Sent: 5/17/2004 4:01 PM
Subject: Re: BFD question

"Bloch, Jack" <Jack.Bloch@icn.siemens.com> writes:

> The call to bfd_get_file_flags returns a 0. The file is indeed an
elf32-i386
> target.

What does objdump -f return on the file?

Has the file perhaps been stripped?

Ian

Re: BFD question

[Ian Lance Taylor]

"Bloch, Jack" <Jack.Bloch@icn.siemens.com> writes:

> objdump -f Coregen
> 
> Coregen:     file format elf32-i386
> architecture: i386, flags 0x00000112:
> EXEC_P, HAS_SYMS, D_PAGED
> start address 0x08048400
> 
> 
> This looks good to me.
> 
> By the way, I forgot to show in my code listing that p_file is a char *
> passed in as a parameter ans is set to "/usr/coretest/Coregen"

Well, objdump thinks the value of bfd_get_file_flags is 0x112.

Your code looks OK at a cursory glance.  I don't know what the problem
is.  Sorry.

Ian