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DWARF_GET_RELOCATION_... BSD Library Functions Manual DWARF_GET_RELOCATION_...

NAME
     dwarf_get_relocation_info -- retrieve generated relocation	arrays

LIBRARY
     DWARF Access Library (libdwarf, -ldwarf)

SYNOPSIS
     #include <libdwarf.h>

     int
     dwarf_get_relocation_info(Dwarf_P_Debug dbg,
	 Dwarf_Signed *elf_section_index, Dwarf_Signed *elf_section_link,
	 Dwarf_Unsigned	*reloc_entry_count, Dwarf_Relocation_Data *reloc_buf,
	 Dwarf_Error *err);

DESCRIPTION
     The function dwarf_get_relocation_info() is used to retrieve the reloca-
     tion arrays generated by a	prior call to dwarf_transform_to_disk_form(3).

     Each call to this function	retrieves the next available relocation	array.
     Application code should call this function	repeatly to retrieve all the
     relocation	arrays.	 The total number of generated relocation arrays re-
     trievable by this function	may be obtained	by calling function
     dwarf_get_relocation_info_count(3).

     Argument dbg should reference a DWARF producer instance allocated using
     dwarf_producer_init(3) in sequence. or dwarf_producer_init_b(3).  The
     DW_DLC_SYMBOLIC_RELOCATIONS flag should have been set on the DWARF	pro-
     ducer instance.

     Argument elf_section_index	should point to	a location which will be set
     to	the ELF	section	index of the relocation	section	to which the retrieved
     relocation	array belongs.

     Argument elf_section_link should point to a location which	will be	set to
     the section index of the ELF section to which the retrieved relocation
     array applies.

     Argument reloc_entry_count	should point to	a location which will be set
     to	the total number of relocation entries contained in the	relocation ar-
     ray.

     Argument reloc_buf	should point to	a location which will be set to	a
     pointer to	the retrieved array of relocation entries.

     If	argument err is	not NULL, it will be used to store error information
     in	case of	an error.

     The retrieved relocation entries are described using structure
     Dwarf_Relocation_Data_s, defined in the header file <libdwarf.h>:

	   typedef struct Dwarf_Relocation_Data_s {
		   unsigned char drd_type;
		   unsigned char drd_length;
		   Dwarf_Unsigned drd_offset;
		   Dwarf_Unsigned drd_symbol_index;
	   } *Dwarf_Relocation_Data;

     Struct Dwarf_Relocation_Data_s consists of	following fields:
	   drd_type	     The type code of the relocation entry.  The
			     Dwarf_Rel_Type enumeration	defined	in the header
			     file <libdwarf.h> specifies legal values for this
			     field.
	   drd_length	     The size in bytes of the field to be relocated.
	   drd_offset	     The section-relative offset of the	field to be
			     relocated.
	   drd_symbol_index  The symbol	index associated with the relocation
			     entry.

   Memory Management
     The memory	area used for the relocation arrays is managed by the DWARF
     Access Library (libdwarf, -ldwarf).  The function dwarf_producer_finish()
     may be used to release it,	along with other resources associated with the
     producer instance.

RETURN VALUES
     On	success, function dwarf_get_relocation_info() returns DW_DLV_OK.  It
     returns DW_DLV_NO_ENTRY if	there were no more relocation arrays to	re-
     trieve, or	if the flag DW_DLC_SYMBOLIC_RELOCATIONS	was not	set on the
     producer instance.	 In case of an error, function
     dwarf_get_relocation_info() returns DW_DLV_ERROR and sets the argument
     err.

ERRORS
     Function dwarf_get_relocation_info() can fail with:

     [DW_DLE_ARGUMENT]	One of the arguments dbg, elf_section_index,
			elf_section_link, reloc_entry_count or reloc_buf was
			NULL.

     [DW_DLE_NO_ENTRY]	There were no more ELF relocation arrays to retrieve.

     [DW_DLE_NO_ENTRY]	The flag DW_DLC_SYMBOLIC_RELOCATIONS was not set on
			the producer instance.

     [DW_DLE_NO_ENTRY]	Function dwarf_transform_to_disk_form(3) was not
			called prior to	calling	function
			dwarf_get_relocation_info().

EXAMPLES
     To	generate relocation entries and	retrieve them, use:

	   Dwarf_P_Debug dbg;
	   Dwarf_Relocation_Data buf;
	   Dwarf_Signed	count, index, link;
	   Dwarf_Unsigned reloc_cnt, entry_cnt;
	   Dwarf_Error de;
	   int version,	i, j;

	   /*
	    * Assume that dbg refers to	a DWARF	producer instance created
	    * created with DW_DLC_SYMBOLIC_RELOCATIONS flag set	and that
	    * application code has added DWARF debugging information
	    * to the producer instance.
	    */
	   if ((count =	dwarf_transform_to_disk_form(dbg, &de))	==
	       DW_DLV_NOCOUNT) {
		   warnx("dwarf_transform_to_disk_form failed: %s",
		       dwarf_errmsg(-1));
		   return;
	   }

	   /* ... process generated section byte streams ... */
	   if (dwarf_get_relocation_info_count(dbg, &reloc_cnt,	&version, &de) !=
	       DW_DLV_OK) {
		   warnx("dwarf_get_relocation_info_count failed: %s",
		       dwarf_errmsg(-1));
		   return;
	   }

	   for (i = 0; (Dwarf_Unsigned)	i < reloc_cnt; i++) {
		   if (dwarf_get_relocation_info(dbg, &index, &link, &entry_cnt,
		       &buf, &de) != DW_DLV_OK)	{
			   warnx("dwarf_get_relocation_info failed: %s",
			       dwarf_errmsg(-1));
			   continue;
		   }
		   for (j = 0; (Dwarf_Unsigned)	j < entry_cnt; j++) {
			   /* ...use each reloc	data in	buf[j]... */
		   }
	   }

	   dwarf_producer_finish(dbg, &de);

SEE ALSO
     dwarf(3), dwarf_get_relocation_info_count(3),
     dwarf_reset_section_bytes(3), dwarf_producer_finish(3),
     dwarf_producer_init(3), dwarf_producer_init_b(3),
     dwarf_transform_to_disk_form(3)

BSD			       September 3, 2011			   BSD

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | EXAMPLES | SEE ALSO

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