NAME
dwarf_get_fde_list —
retrieve frame
information
LIBRARY
DWARF Access Library (libdwarf, -ldwarf)
SYNOPSIS
#include <libdwarf.h>
int
dwarf_get_fde_list(
Dwarf_Debug dbg,
Dwarf_Cie **cie_list,
Dwarf_Signed
*cie_count,
Dwarf_Fde **fde_list,
Dwarf_Signed *fde_count,
Dwarf_Error
*err);
int
dwarf_get_fde_list_eh(
Dwarf_Debug dbg,
Dwarf_Cie **cie_list,
Dwarf_Signed
*cie_count,
Dwarf_Fde **fde_list,
Dwarf_Signed *fde_count,
Dwarf_Error
*err);
DESCRIPTION
These functions retrieve frame related information for the specified DWARF debug
context.
Function
dwarf_get_fde_list() retrieves frame information from
the DWARF section named “.debug_frame”. For objects containing GNU
style C++ exception handling information, the function
dwarf_get_fde_list_eh() retrieves frame information from the
section named “.eh_frame”.
Frame information is returned using opaque descriptors of type
Dwarf_Cie and
Dwarf_Fde.
Applications need to use the other frame related functions in the DWARF(3) API
set to retrieve the information contained in these descriptors.
Argument
dbg should reference a DWARF debug context
allocated using
dwarf_init(3).
Argument
cie_list should point to a location that will be
set to a pointer to an array of
Dwarf_Cie descriptors.
Argument
cie_count should point to a location that will be
set to the number of
Dwarf_Cie descriptors returned.
Argument
fde_list should point to a location that will be
set to a pointer to an array of
Dwarf_Fde descriptors.
Argument
fde_count should point to a location that will be
set to the number of
Dwarf_Fde descriptors returned.
If argument
err is not NULL, it will be used to store
error information in case of an error.
Memory Management
The memory areas used for the arrays returned in arguments
cie_list and
fde_list are owned by
the
DWARF Access Library (libdwarf, -ldwarf).
Application code should not attempt to directly free these areas. Portable
applications should instead use the
dwarf_fde_cie_list_dealloc(3)
function to indicate that these memory areas may be freed.
RETURN VALUES
On success, these functions returns
DW_DLV_OK
. They
return
DW_DLV_NO_ENTRY
if there is no frame
information associated with the given DWARF debug context. In case of an
error, they return
DW_DLV_ERROR
and set the argument
err.
ERRORS
These functions may fail with the following errors:
-
-
- [
DW_DLE_ARGUMENT
]
- One of the arguments dbg,
cie_list, cie_count,
fde_list or fde_count was
NULL.
-
-
- [
DW_DLE_NO_ENTRY
]
- There is no frame information associated with the giving
DWARF debug context.
EXAMPLE
To obtain frame information from the “.debug_frame” section, use:
Dwarf_Debug dbg;
Dwarf_Cie *cie_list, cie;
Dwarf_Fde *fde_list, fde;
Dwarf_Off fde_offset, cie_offset;
Dwarf_Unsigned func_len, fde_length, fde_instlen;
Dwarf_Signed cie_count, fde_count, cie_index;
Dwarf_Addr low_pc;
Dwarf_Ptr fde_addr, fde_inst, cie_inst;
Dwarf_Error de;
int i;
if (dwarf_get_fde_list(dbg, &cie_list, &cie_count,
&fde_list, &fde_count, &de) != DW_DLV_OK) {
errx(EXIT_FAILURE, "dwarf_get_fde_list failed: %s",
dwarf_errmsg(de));
}
for (i = 0; i < fde_count; i++) {
if (dwarf_get_fde_n(fde_list, i, &fde, &de) != DW_DLV_OK) {
warnx("dwarf_get_fde_n failed: %s",
dwarf_errmsg(de));
continue;
}
if (dwarf_get_cie_of_fde(fde, &cie, &de) != DW_DLV_OK) {
warnx("dwarf_get_fde_n failed: %s",
dwarf_errmsg(de));
continue;
}
if (dwarf_get_fde_range(fde, &low_pc, &func_len, &fde_addr,
&fde_length, &cie_offset, &cie_index, &fde_offset,
&de) != DW_DLV_OK) {
warnx("dwarf_get_fde_range failed: %s",
dwarf_errmsg(de));
continue;
}
if (dwarf_get_fde_instr_bytes(fde, &fde_inst, &fde_instlen,
&de) != DW_DLV_OK) {
warnx("dwarf_get_fde_instr_bytes failed: %s",
dwarf_errmsg(de));
continue;
}
/* ... Use the retrieved frame information ... */
}
/* Indicate that the returned arrays may be freed. */
dwarf_fde_cie_list_dealloc(dbg, cie_list, cie_count, fde_list,
fde_count);
SEE ALSO
dwarf(3),
dwarf_get_cie_index(3),
dwarf_get_cie_of_fde(3),
dwarf_get_fde_at_pc(3),
dwarf_get_fde_instr_bytes(3),
dwarf_get_fde_n(3),
dwarf_get_fde_range(3),
dwarf_fde_cie_list_dealloc(3),
dwarf_set_frame_cfa_value(3),
dwarf_set_frame_rule_table_size(3),
dwarf_set_frame_rule_initial_value(3),
dwarf_set_frame_same_value(3),
dwarf_set_frame_undefined_value(3)