359 lines
10 KiB
C
359 lines
10 KiB
C
/* Read the export table symbols from a portable executable and
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convert to internal format, for GDB. Used as a last resort if no
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debugging symbols recognized.
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Copyright (C) 2003, 2007, 2008, 2009 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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Contributed by Raoul M. Gough (RaoulGough@yahoo.co.uk). */
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#include "coff-pe-read.h"
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#include "bfd.h"
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#include "defs.h"
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#include "gdbtypes.h"
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#include "symtab.h"
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#include "symfile.h"
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#include "objfiles.h"
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/* Internal section information */
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struct read_pe_section_data
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{
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CORE_ADDR vma_offset; /* Offset to loaded address of section. */
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unsigned long rva_start; /* Start offset within the pe. */
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unsigned long rva_end; /* End offset within the pe. */
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enum minimal_symbol_type ms_type; /* Type to assign symbols in section. */
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};
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#define PE_SECTION_INDEX_TEXT 0
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#define PE_SECTION_INDEX_DATA 1
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#define PE_SECTION_INDEX_BSS 2
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#define PE_SECTION_TABLE_SIZE 3
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#define PE_SECTION_INDEX_INVALID -1
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/* Get the index of the named section in our own array, which contains
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text, data and bss in that order. Return PE_SECTION_INDEX_INVALID
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if passed an unrecognised section name. */
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static int
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read_pe_section_index (const char *section_name)
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{
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if (strcmp (section_name, ".text") == 0)
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{
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return PE_SECTION_INDEX_TEXT;
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}
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else if (strcmp (section_name, ".data") == 0)
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{
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return PE_SECTION_INDEX_DATA;
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}
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else if (strcmp (section_name, ".bss") == 0)
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{
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return PE_SECTION_INDEX_BSS;
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}
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else
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{
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return PE_SECTION_INDEX_INVALID;
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}
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}
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/* Record the virtual memory address of a section. */
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static void
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get_section_vmas (bfd *abfd, asection *sectp, void *context)
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{
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struct read_pe_section_data *sections = context;
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int sectix = read_pe_section_index (sectp->name);
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if (sectix != PE_SECTION_INDEX_INVALID)
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{
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/* Data within the section start at rva_start in the pe and at
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bfd_get_section_vma() within memory. Store the offset. */
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sections[sectix].vma_offset
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= bfd_get_section_vma (abfd, sectp) - sections[sectix].rva_start;
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}
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}
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/* Create a minimal symbol entry for an exported symbol. */
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static void
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add_pe_exported_sym (char *sym_name,
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unsigned long func_rva,
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const struct read_pe_section_data *section_data,
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const char *dll_name, struct objfile *objfile)
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{
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/* Add the stored offset to get the loaded address of the symbol. */
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CORE_ADDR vma = func_rva + section_data->vma_offset;
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char *qualified_name = 0;
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int dll_name_len = strlen (dll_name);
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int count;
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/* Generate a (hopefully unique) qualified name using the first part
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of the dll name, e.g. KERNEL32!AddAtomA. This matches the style
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used by windbg from the "Microsoft Debugging Tools for Windows". */
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qualified_name = xmalloc (dll_name_len + strlen (sym_name) + 2);
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strncpy (qualified_name, dll_name, dll_name_len);
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qualified_name[dll_name_len] = '!';
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strcpy (qualified_name + dll_name_len + 1, sym_name);
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prim_record_minimal_symbol (qualified_name,
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vma, section_data->ms_type, objfile);
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xfree (qualified_name);
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/* Enter the plain name as well, which might not be unique. */
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prim_record_minimal_symbol (sym_name, vma, section_data->ms_type, objfile);
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}
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/* Truncate a dll_name at the first dot character. */
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static void
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read_pe_truncate_name (char *dll_name)
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{
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while (*dll_name)
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{
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if ((*dll_name) == '.')
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{
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*dll_name = '\0'; /* truncates and causes loop exit. */
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}
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else
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{
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++dll_name;
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}
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}
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}
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/* Low-level support functions, direct from the ld module pe-dll.c. */
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static unsigned int
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pe_get16 (bfd *abfd, int where)
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{
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unsigned char b[2];
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bfd_seek (abfd, (file_ptr) where, SEEK_SET);
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bfd_bread (b, (bfd_size_type) 2, abfd);
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return b[0] + (b[1] << 8);
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}
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static unsigned int
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pe_get32 (bfd *abfd, int where)
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{
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unsigned char b[4];
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bfd_seek (abfd, (file_ptr) where, SEEK_SET);
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bfd_bread (b, (bfd_size_type) 4, abfd);
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return b[0] + (b[1] << 8) + (b[2] << 16) + (b[3] << 24);
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}
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static unsigned int
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pe_as32 (void *ptr)
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{
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unsigned char *b = ptr;
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return b[0] + (b[1] << 8) + (b[2] << 16) + (b[3] << 24);
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}
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/* Read the (non-debug) export symbol table from a portable
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executable. Code originally lifted from the ld function
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pe_implied_import_dll in pe-dll.c. */
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void
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read_pe_exported_syms (struct objfile *objfile)
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{
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bfd *dll = objfile->obfd;
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unsigned long pe_header_offset, opthdr_ofs, num_entries, i;
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unsigned long export_rva, export_size, nsections, secptr, expptr;
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unsigned long exp_funcbase;
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unsigned char *expdata, *erva;
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unsigned long name_rvas, ordinals, nexp, ordbase;
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char *dll_name;
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int is_pe64 = 0;
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int is_pe32 = 0;
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/* Array elements are for text, data and bss in that order
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Initialization with start_rva > end_rva guarantees that
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unused sections won't be matched. */
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struct read_pe_section_data section_data[PE_SECTION_TABLE_SIZE]
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= { {0, 1, 0, mst_text},
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{0, 1, 0, mst_data},
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{0, 1, 0, mst_bss}
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};
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struct cleanup *back_to = 0;
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char const *target = bfd_get_target (objfile->obfd);
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is_pe64 = ((strcmp (target, "pe-x86-64") == 0)
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|| (strcmp (target, "pei-x86-64") == 0));
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is_pe32 = ((strcmp (target, "pe-i386") == 0)
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|| (strcmp (target, "pei-i386") == 0));
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if (!is_pe32 && !is_pe64)
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{
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/* This is not an i386 format file. Abort now, because the code
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is untested on anything else. *FIXME* test on further
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architectures and loosen or remove this test. */
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return;
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}
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/* Get pe_header, optional header and numbers of export entries. */
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pe_header_offset = pe_get32 (dll, 0x3c);
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opthdr_ofs = pe_header_offset + 4 + 20;
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if (is_pe64)
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num_entries = pe_get32 (dll, opthdr_ofs + 108);
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else
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num_entries = pe_get32 (dll, opthdr_ofs + 92);
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if (num_entries < 1) /* No exports. */
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{
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return;
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}
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if (is_pe64)
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{
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export_rva = pe_get32 (dll, opthdr_ofs + 112);
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export_size = pe_get32 (dll, opthdr_ofs + 116);
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}
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else
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{
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export_rva = pe_get32 (dll, opthdr_ofs + 96);
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export_size = pe_get32 (dll, opthdr_ofs + 100);
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}
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nsections = pe_get16 (dll, pe_header_offset + 4 + 2);
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secptr = (pe_header_offset + 4 + 20 +
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pe_get16 (dll, pe_header_offset + 4 + 16));
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expptr = 0;
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/* Get the rva and size of the export section. */
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for (i = 0; i < nsections; i++)
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{
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char sname[8];
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unsigned long secptr1 = secptr + 40 * i;
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unsigned long vaddr = pe_get32 (dll, secptr1 + 12);
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unsigned long vsize = pe_get32 (dll, secptr1 + 16);
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unsigned long fptr = pe_get32 (dll, secptr1 + 20);
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bfd_seek (dll, (file_ptr) secptr1, SEEK_SET);
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bfd_bread (sname, (bfd_size_type) 8, dll);
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if (vaddr <= export_rva && vaddr + vsize > export_rva)
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{
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expptr = fptr + (export_rva - vaddr);
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if (export_rva + export_size > vaddr + vsize)
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export_size = vsize - (export_rva - vaddr);
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break;
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}
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}
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if (export_size == 0)
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{
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/* Empty export table. */
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return;
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}
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/* Scan sections and store the base and size of the relevant sections. */
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for (i = 0; i < nsections; i++)
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{
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unsigned long secptr1 = secptr + 40 * i;
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unsigned long vsize = pe_get32 (dll, secptr1 + 8);
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unsigned long vaddr = pe_get32 (dll, secptr1 + 12);
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unsigned long flags = pe_get32 (dll, secptr1 + 36);
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char sec_name[9];
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int sectix;
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sec_name[8] = '\0';
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bfd_seek (dll, (file_ptr) secptr1 + 0, SEEK_SET);
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bfd_bread (sec_name, (bfd_size_type) 8, dll);
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sectix = read_pe_section_index (sec_name);
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if (sectix != PE_SECTION_INDEX_INVALID)
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{
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section_data[sectix].rva_start = vaddr;
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section_data[sectix].rva_end = vaddr + vsize;
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}
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}
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expdata = (unsigned char *) xmalloc (export_size);
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back_to = make_cleanup (xfree, expdata);
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bfd_seek (dll, (file_ptr) expptr, SEEK_SET);
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bfd_bread (expdata, (bfd_size_type) export_size, dll);
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erva = expdata - export_rva;
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nexp = pe_as32 (expdata + 24);
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name_rvas = pe_as32 (expdata + 32);
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ordinals = pe_as32 (expdata + 36);
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ordbase = pe_as32 (expdata + 16);
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exp_funcbase = pe_as32 (expdata + 28);
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/* Use internal dll name instead of full pathname. */
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dll_name = pe_as32 (expdata + 12) + erva;
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bfd_map_over_sections (dll, get_section_vmas, section_data);
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/* Adjust the vma_offsets in case this PE got relocated. This
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assumes that *all* sections share the same relocation offset
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as the text section. */
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for (i = 0; i < PE_SECTION_TABLE_SIZE; i++)
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{
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section_data[i].vma_offset
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+= ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
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}
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/* Truncate name at first dot. Should maybe also convert to all
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lower case for convenience on Windows. */
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read_pe_truncate_name (dll_name);
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/* Iterate through the list of symbols. */
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for (i = 0; i < nexp; i++)
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{
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/* Pointer to the names vector. */
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unsigned long name_rva = pe_as32 (erva + name_rvas + i * 4);
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/* Pointer to the function address vector. */
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unsigned long func_rva = pe_as32 (erva + exp_funcbase + i * 4);
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/* Find this symbol's section in our own array. */
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int sectix = 0;
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for (sectix = 0; sectix < PE_SECTION_TABLE_SIZE; ++sectix)
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{
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if ((func_rva >= section_data[sectix].rva_start)
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&& (func_rva < section_data[sectix].rva_end))
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{
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add_pe_exported_sym (erva + name_rva,
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func_rva,
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section_data + sectix, dll_name, objfile);
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break;
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}
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}
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}
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/* discard expdata. */
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do_cleanups (back_to);
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}
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