dwarf_get_section_bytes —
retrieve ELF section byte streams
DWARF Access Library (libdwarf, -ldwarf)
#include
<libdwarf.h>
Dwarf_Ptr
dwarf_get_section_bytes(
Dwarf_P_Debug
dbg,
Dwarf_Signed dwarf_section,
Dwarf_Signed *elf_section_index,
Dwarf_Unsigned *length,
Dwarf_Error *err);
Function
dwarf_get_section_bytes() returns the ELF
section byte streams generated by a prior call to function
dwarf_transform_to_disk_form(3).
Each call to function
dwarf_get_section_bytes()
will return the byte stream for one ELF section. The first call to this
function will always return the first ELF section, and the subsequent calls
will return the rest of sections in the order when they were generated, until
the last one. The total number of sections generated is returned by the
function
dwarf_transform_to_disk_form(3).
Argument
dbg should reference a DWARF producer
instance allocated using the functions
dwarf_producer_init(3)
or
dwarf_producer_init_b(3).
Argument
dwarf_section is currently ignored.
Argument
elf_section_index should point to a
location which will be set to the section index value of the returned ELF
section.
Argument
length should point to a location
which will hold the length in bytes of the returned ELF section.
If argument
err is not NULL, it will be used to
store error information in case of an error.
The memory areas used for the returned ELF section byte streams should be freed
using the function
dwarf_producer_finish().
On success, function
dwarf_get_section_bytes()
returns a pointer to a ELF section byte stream. In case of an error, function
dwarf_get_section_bytes() will return NULL and
set the argument
err.
To generate and retrieve ELF section byte streams, use:
Dwarf_P_Debug dbg;
Dwarf_Signed count, i, sec_index;
Dwarf_Unsigned len;
Dwarf_Ptr bytes;
Dwarf_Error de;
/* ... Assume that `dbg' refers to a DWARF producer instance,
* 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;
}
/* Retrieve section data. */
for (i = 0; i < count; i++) {
bytes = dwarf_get_section_bytes(dbg, i, &sec_index, &len,
&de);
if (bytes == NULL) {
warnx("dwarf_get_section_bytes failed: %s",
dwarf_errmsg(-1));
continue;
}
/* ... use the returned byte stream ... */
}
/* Release resources. */
dwarf_producer_finish(dbg, &de);
Function
dwarf_get_section_bytes() can fail with:
-
-
- [
DW_DLE_ARGUMENT
]
- One of the arguments dbg,
elf_section_index, or
length was NULL.
-
-
- [
DW_DLE_NO_ENTRY
]
- There were no more ELF sections to retrieve, or the
function was called before a call to
dwarf_transform_to_disk_form(3).
dwarf(3),
dwarf_producer_finish(3),
dwarf_producer_init(3),
dwarf_producer_init_b(3),
dwarf_reset_section_bytes(3),
dwarf_transform_to_disk_form(3)