Files
sysprof/elfparser.c
Soren Sandmann 2bc2e3658d Add beginning of an ELF parser.
2006-08-15  Soren Sandmann  <sandmann@redhat.com>

	Add beginning of an ELF parser.

	* binparser.[ch]: New files
	* elfparser.[ch]: New files
	* testelf.c: New file
	* Makefile.am (testelf_SOURCES): Add new testelf program.
2006-08-16 03:31:10 +00:00

459 lines
9.9 KiB
C

#include <string.h>
#include <elf.h>
#include "binparser.h"
#include "elfparser.h"
typedef struct SymbolTable SymbolTable;
struct SymbolTable
{
};
struct ElfSym
{
};
struct ElfParser
{
BinParser *parser;
BinFormat *header;
BinFormat *strtab_format;
BinFormat *shn_entry;
BinFormat *sym_format;
gsize strtab_offset;
gsize str_table;
};
static void make_formats (ElfParser *parser,
gboolean is_64,
gboolean is_big_endian);
#if 0
BinFormat *str_tab = bin_field_new_string ("string", make_string());
gsize offset = find_it();
#endif
#if 0
static void
parse_elf (const guchar *data,
gsize length)
{
gboolean is_64, is_big_endian;
BinFormat *elf_header;
BinFormat *shn_entry;
BinParser *parser;
BinParser *sh_parser;
BinFormat *sym;
int i;
find_elf_type (data, length, &is_64, &is_big_endian);
parser = bin_parser_new (data, length);
bin_parser_begin (parser, elf_header, 0);
g_print ("section header offset: %u\n",
bin_parser_get_uint ("e_shoff"));
g_print ("There are %llu sections\n",
bin_parser_get_uint (parser, "e_shnum"));
}
#endif
static const char *
elf_lookup_string (ElfParser *parser, int offset)
{
const char *result;
/* This function has a midleading name. In reality
* it only looks up in the section header table
*/
bin_parser_begin (parser->parser,
NULL, parser->strtab_offset + offset);
result = bin_parser_get_string (parser->parser);
bin_parser_end (parser->parser);
return result;
}
static gboolean
find_elf_type (const guchar *data, gsize length,
gboolean *is_64, gboolean *is_be)
{
/* FIXME: this function should be able to return an error */
if (length < EI_NIDENT)
return FALSE;
/* 32 or 64? */
if (data[EI_CLASS] == ELFCLASS32)
{
*is_64 = FALSE;
}
else if (data[EI_CLASS] == ELFCLASS64)
{
*is_64 = TRUE;
}
else
{
/* FIXME: set_error */
return FALSE;
}
/* big or little endian? */
if (data[EI_DATA] == ELFDATA2LSB)
{
*is_be = FALSE;
}
else if (data[EI_DATA] == ELFDATA2MSB)
{
*is_be = TRUE;
}
else
{
/* FIXME: set error */
return FALSE;
}
g_print ("This elf file is %s %s\n",
*is_64? "64 bit" : "32 bit",
*is_be? "big endiann" : "little endian");
return TRUE;
}
static BinField *
make_word (gboolean is_64)
{
if (is_64)
return bin_field_new_uint64 ();
else
return bin_field_new_uint32 ();
}
static void
dump_symbol_table (ElfParser *parser,
gsize offset,
gsize size)
{
int i;
if (!parser->str_table)
{
g_print ("no string table\n");
return;
}
g_print ("dumping symbol table at %d\n", offset);
bin_parser_begin (parser->parser, parser->sym_format, offset);
for (i = 0; i < 200; ++i)
{
guint64 idx;
bin_parser_index (parser->parser, i);
idx = bin_parser_get_uint (parser->parser, "st_name");
const char *result;
gsize size;
#if 0
g_print ("addr: %p\n", bin_parser_get_address (parser->parser, "st_name"));
#endif
#if 0
g_print ("idx: %d\n", idx);
#endif
size = bin_parser_get_uint (parser->parser, "st_size");
bin_parser_begin (parser->parser,
NULL, parser->str_table + idx);
result = bin_parser_get_string (parser->parser);
bin_parser_end (parser->parser);
g_print ("%d symbol: size: %d, %s.\n",
i, size, result);
}
bin_parser_end (parser->parser);
}
ElfParser *
elf_parser_new (const guchar *data, gsize length)
{
ElfParser *parser;
gboolean is_64, is_big_endian;
int n_sections;
int section_name_table;
int i;
if (!find_elf_type (data, length, &is_64, &is_big_endian))
{
/* FIXME: set error */
return NULL;
}
parser = g_new0 (ElfParser, 1);
parser->parser = bin_parser_new (data, length);
make_formats (parser, is_64, is_big_endian);
bin_parser_begin (parser->parser, parser->header, 0);
n_sections =
bin_parser_get_uint (parser->parser, "e_shnum");
section_name_table =
bin_parser_get_uint (parser->parser, "e_shstrndx");
bin_parser_begin (
parser->parser, parser->shn_entry,
bin_parser_get_uint (parser->parser, "e_shoff"));
bin_parser_index (parser->parser, section_name_table);
parser->strtab_offset =
bin_parser_get_uint (parser->parser, "sh_offset");
for (i = 0; i < n_sections; ++i)
{
const char *name;
int offset;
bin_parser_index (parser->parser, i);
offset = bin_parser_get_uint (parser->parser, "sh_name");
name = elf_lookup_string (parser, offset);
if (strcmp (name, ".strtab") == 0)
{
parser->str_table = bin_parser_get_uint (
parser->parser, "sh_offset");
}
}
for (i = 0; i < n_sections; ++i)
{
const char *name;
int offset;
const char *type;
bin_parser_index (parser->parser, i);
offset = bin_parser_get_uint (parser->parser, "sh_name");
name = elf_lookup_string (parser, offset);
switch (bin_parser_get_uint (parser->parser, "sh_type"))
{
case SHT_NULL:
type = "undefined";
break;
case SHT_PROGBITS:
type = "progbits";
break;
case SHT_SYMTAB:
type = "symbol table";
dump_symbol_table (
parser,
bin_parser_get_uint (parser->parser, "sh_offset"),
bin_parser_get_uint (parser->parser, "sh_size"));
break;
case SHT_STRTAB:
type = "string table";
break;
case SHT_RELA:
type = "relocations with explicit addends";
break;
case SHT_HASH:
type = "symbol hash table";
break;
case SHT_DYNAMIC:
type = "Information for dynamic linking";
break;
case SHT_NOTE:
type = "note";
break;
case SHT_NOBITS:
type = "nobits";
break;
case SHT_REL:
type = "relocations without explicit addends";
break;
case SHT_SHLIB:
type = "reserved with unspecified semantics";
break;
case SHT_DYNSYM:
type = "dynamic symbols";
break;
case SHT_LOPROC:
type = "loproc";
break;
case SHT_HIPROC:
type = "hiproc";
break;
case SHT_LOUSER:
type = "louser:";
break;
case SHT_HIUSER:
type = "hiuser";
break;
default:
type = "<unknown>";
break;
}
g_print ("%s [%s] (%d)\n", name, type, offset);
}
bin_parser_end (parser->parser);
bin_parser_end (parser->parser);
return parser;
}
static const char *
get_string (BinParser *parser,
gsize table,
gsize offset)
{
const char *result = NULL;
bin_parser_begin (parser, NULL, table + offset);
result = bin_parser_get_string (parser);
bin_parser_end (parser);
return result;
}
static gssize
find_section (ElfParser *parser,
const char *name)
{
int n_sections;
int section_name_table;
int section_headers_offset;
int section_name_table_offset;
BinParser *bparser = parser->parser;
int i;
gssize result;
bin_parser_begin (parser->parser, parser->header, 0);
n_sections = bin_parser_get_uint (bparser, "e_shnum");
section_name_table = bin_parser_get_uint (bparser, "e_shstrndx");
section_headers_offset = bin_parser_get_uint (bparser, "e_shoff");
bin_parser_begin (bparser, parser->shn_entry, section_headers_offset);
bin_parser_index (bparser, section_name_table);
section_name_table_offset = bin_parser_get_uint (bparser, "sh_offset");
result = -1;
for (i = 0; i < n_sections; ++i)
{
const char *section_name;
gsize name_offset;
bin_parser_index (bparser, i);
name_offset = bin_parser_get_uint (bparser, "sh_name");
section_name = get_string (
bparser, section_name_table_offset, name_offset);
if (strcmp (section_name, name) == 0)
{
result = bin_parser_get_uint (bparser, "sh_offset");
goto out;
}
}
out:
bin_parser_end (bparser);
g_print ("found %s at %d\n", name, result);
return result;
}
const ElfSym *
elf_parser_lookup_symbol (ElfParser *parser,
gulong address)
{
gssize symtab_offset = find_section (parser, ".symtab");
gssize strtab_offset = find_section (parser, ".strtab");
gssize dynsym_offset = find_section (parser, ".dynsym");
gssize dynstr_offset = find_section (parser, ".dynstr");
return NULL;
}
static void
make_formats (ElfParser *parser, gboolean is_64, gboolean is_big_endian)
{
parser->header = bin_format_new (
is_big_endian,
"e_ident", bin_field_new_fixed_array (EI_NIDENT, 1),
"e_type", bin_field_new_uint16 (),
"e_machine", bin_field_new_uint16 (),
"e_version", bin_field_new_uint32 (),
"e_entry", make_word (is_64),
"e_phoff", make_word (is_64),
"e_shoff", make_word (is_64),
"e_flags", bin_field_new_uint32 (),
"e_ehsize", bin_field_new_uint16 (),
"e_phentsize", bin_field_new_uint16 (),
"e_phnum", bin_field_new_uint16 (),
"e_shentsize", bin_field_new_uint16 (),
"e_shnum", bin_field_new_uint16 (),
"e_shstrndx", bin_field_new_uint16 (),
NULL);
parser->shn_entry = bin_format_new (
is_big_endian,
"sh_name", bin_field_new_uint32 (),
"sh_type", bin_field_new_uint32 (),
"sh_flags", make_word (is_64),
"sh_addr", make_word (is_64),
"sh_offset", make_word (is_64),
"sh_size", make_word (is_64),
"sh_link", bin_field_new_uint32 (),
"sh_info", bin_field_new_uint32 (),
"sh_addralign", make_word (is_64),
"sh_entsize", make_word (is_64),
NULL);
if (is_64)
{
parser->sym_format = bin_format_new (
is_big_endian,
"st_name", bin_field_new_uint32 (),
"st_info", bin_field_new_uint8 (),
"st_other", bin_field_new_uint8 (),
"st_shndx", bin_field_new_uint16 (),
"st_value", bin_field_new_uint64 (),
"st_size", bin_field_new_uint64 (),
NULL);
}
else
{
parser->sym_format = bin_format_new (
is_big_endian,
"st_name", bin_field_new_uint32 (),
"st_value", bin_field_new_uint32 (),
"st_size", bin_field_new_uint32 (),
"st_info", bin_field_new_uint8 (),
"st_other", bin_field_new_uint8 (),
"st_shndx", bin_field_new_uint16 (),
NULL);
}
}