/* Read the export table symbols from a portable executable and convert to internal format, for GDB. Used as a last resort if no debugging symbols recognized. Copyright (C) 2003, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc. This file is part of GDB. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. Contributed by Raoul M. Gough (RaoulGough@yahoo.co.uk). */ #include "coff-pe-read.h" #include "bfd.h" #include "defs.h" #include "gdbtypes.h" #include "symtab.h" #include "symfile.h" #include "objfiles.h" /* Internal section information */ struct read_pe_section_data { CORE_ADDR vma_offset; /* Offset to loaded address of section. */ unsigned long rva_start; /* Start offset within the pe. */ unsigned long rva_end; /* End offset within the pe. */ enum minimal_symbol_type ms_type; /* Type to assign symbols in section. */ }; #define PE_SECTION_INDEX_TEXT 0 #define PE_SECTION_INDEX_DATA 1 #define PE_SECTION_INDEX_BSS 2 #define PE_SECTION_TABLE_SIZE 3 #define PE_SECTION_INDEX_INVALID -1 /* Get the index of the named section in our own array, which contains text, data and bss in that order. Return PE_SECTION_INDEX_INVALID if passed an unrecognised section name. */ static int read_pe_section_index (const char *section_name) { if (strcmp (section_name, ".text") == 0) { return PE_SECTION_INDEX_TEXT; } else if (strcmp (section_name, ".data") == 0) { return PE_SECTION_INDEX_DATA; } else if (strcmp (section_name, ".bss") == 0) { return PE_SECTION_INDEX_BSS; } else { return PE_SECTION_INDEX_INVALID; } } /* Record the virtual memory address of a section. */ static void get_section_vmas (bfd *abfd, asection *sectp, void *context) { struct read_pe_section_data *sections = context; int sectix = read_pe_section_index (sectp->name); if (sectix != PE_SECTION_INDEX_INVALID) { /* Data within the section start at rva_start in the pe and at bfd_get_section_vma() within memory. Store the offset. */ sections[sectix].vma_offset = bfd_get_section_vma (abfd, sectp) - sections[sectix].rva_start; } } /* Create a minimal symbol entry for an exported symbol. */ static void add_pe_exported_sym (char *sym_name, unsigned long func_rva, const struct read_pe_section_data *section_data, const char *dll_name, struct objfile *objfile) { /* Add the stored offset to get the loaded address of the symbol. */ CORE_ADDR vma = func_rva + section_data->vma_offset; char *qualified_name = 0; int dll_name_len = strlen (dll_name); /* Generate a (hopefully unique) qualified name using the first part of the dll name, e.g. KERNEL32!AddAtomA. This matches the style used by windbg from the "Microsoft Debugging Tools for Windows". */ qualified_name = xmalloc (dll_name_len + strlen (sym_name) + 2); strncpy (qualified_name, dll_name, dll_name_len); qualified_name[dll_name_len] = '!'; strcpy (qualified_name + dll_name_len + 1, sym_name); prim_record_minimal_symbol (qualified_name, vma, section_data->ms_type, objfile); xfree (qualified_name); /* Enter the plain name as well, which might not be unique. */ prim_record_minimal_symbol (sym_name, vma, section_data->ms_type, objfile); } /* Truncate a dll_name at the first dot character. */ static void read_pe_truncate_name (char *dll_name) { while (*dll_name) { if ((*dll_name) == '.') { *dll_name = '\0'; /* truncates and causes loop exit. */ } else { ++dll_name; } } } /* Low-level support functions, direct from the ld module pe-dll.c. */ static unsigned int pe_get16 (bfd *abfd, int where) { unsigned char b[2]; bfd_seek (abfd, (file_ptr) where, SEEK_SET); bfd_bread (b, (bfd_size_type) 2, abfd); return b[0] + (b[1] << 8); } static unsigned int pe_get32 (bfd *abfd, int where) { unsigned char b[4]; bfd_seek (abfd, (file_ptr) where, SEEK_SET); bfd_bread (b, (bfd_size_type) 4, abfd); return b[0] + (b[1] << 8) + (b[2] << 16) + (b[3] << 24); } static unsigned int pe_as32 (void *ptr) { unsigned char *b = ptr; return b[0] + (b[1] << 8) + (b[2] << 16) + (b[3] << 24); } /* Read the (non-debug) export symbol table from a portable executable. Code originally lifted from the ld function pe_implied_import_dll in pe-dll.c. */ void read_pe_exported_syms (struct objfile *objfile) { bfd *dll = objfile->obfd; unsigned long pe_header_offset, opthdr_ofs, num_entries, i; unsigned long export_rva, export_size, nsections, secptr, expptr; unsigned long exp_funcbase; unsigned char *expdata, *erva; unsigned long name_rvas, ordinals, nexp, ordbase; char *dll_name; int is_pe64 = 0; int is_pe32 = 0; /* Array elements are for text, data and bss in that order Initialization with start_rva > end_rva guarantees that unused sections won't be matched. */ struct read_pe_section_data section_data[PE_SECTION_TABLE_SIZE] = { {0, 1, 0, mst_text}, {0, 1, 0, mst_data}, {0, 1, 0, mst_bss} }; struct cleanup *back_to = 0; char const *target = bfd_get_target (objfile->obfd); is_pe64 = (strcmp (target, "pe-x86-64") == 0 || strcmp (target, "pei-x86-64") == 0); is_pe32 = (strcmp (target, "pe-i386") == 0 || strcmp (target, "pei-i386") == 0 || strcmp (target, "pe-arm-wince-little") == 0 || strcmp (target, "pei-arm-wince-little") == 0); if (!is_pe32 && !is_pe64) { /* This is not a recognized PE format file. Abort now, because the code is untested on anything else. *FIXME* test on further architectures and loosen or remove this test. */ return; } /* Get pe_header, optional header and numbers of export entries. */ pe_header_offset = pe_get32 (dll, 0x3c); opthdr_ofs = pe_header_offset + 4 + 20; if (is_pe64) num_entries = pe_get32 (dll, opthdr_ofs + 108); else num_entries = pe_get32 (dll, opthdr_ofs + 92); if (num_entries < 1) /* No exports. */ { return; } if (is_pe64) { export_rva = pe_get32 (dll, opthdr_ofs + 112); export_size = pe_get32 (dll, opthdr_ofs + 116); } else { export_rva = pe_get32 (dll, opthdr_ofs + 96); export_size = pe_get32 (dll, opthdr_ofs + 100); } nsections = pe_get16 (dll, pe_header_offset + 4 + 2); secptr = (pe_header_offset + 4 + 20 + pe_get16 (dll, pe_header_offset + 4 + 16)); expptr = 0; /* Get the rva and size of the export section. */ for (i = 0; i < nsections; i++) { char sname[8]; unsigned long secptr1 = secptr + 40 * i; unsigned long vaddr = pe_get32 (dll, secptr1 + 12); unsigned long vsize = pe_get32 (dll, secptr1 + 16); unsigned long fptr = pe_get32 (dll, secptr1 + 20); bfd_seek (dll, (file_ptr) secptr1, SEEK_SET); bfd_bread (sname, (bfd_size_type) 8, dll); if (vaddr <= export_rva && vaddr + vsize > export_rva) { expptr = fptr + (export_rva - vaddr); if (export_rva + export_size > vaddr + vsize) export_size = vsize - (export_rva - vaddr); break; } } if (export_size == 0) { /* Empty export table. */ return; } /* Scan sections and store the base and size of the relevant sections. */ for (i = 0; i < nsections; i++) { unsigned long secptr1 = secptr + 40 * i; unsigned long vsize = pe_get32 (dll, secptr1 + 8); unsigned long vaddr = pe_get32 (dll, secptr1 + 12); char sec_name[9]; int sectix; sec_name[8] = '\0'; bfd_seek (dll, (file_ptr) secptr1 + 0, SEEK_SET); bfd_bread (sec_name, (bfd_size_type) 8, dll); sectix = read_pe_section_index (sec_name); if (sectix != PE_SECTION_INDEX_INVALID) { section_data[sectix].rva_start = vaddr; section_data[sectix].rva_end = vaddr + vsize; } } expdata = (unsigned char *) xmalloc (export_size); back_to = make_cleanup (xfree, expdata); bfd_seek (dll, (file_ptr) expptr, SEEK_SET); bfd_bread (expdata, (bfd_size_type) export_size, dll); erva = expdata - export_rva; nexp = pe_as32 (expdata + 24); name_rvas = pe_as32 (expdata + 32); ordinals = pe_as32 (expdata + 36); ordbase = pe_as32 (expdata + 16); exp_funcbase = pe_as32 (expdata + 28); /* Use internal dll name instead of full pathname. */ dll_name = pe_as32 (expdata + 12) + erva; bfd_map_over_sections (dll, get_section_vmas, section_data); /* Adjust the vma_offsets in case this PE got relocated. This assumes that *all* sections share the same relocation offset as the text section. */ for (i = 0; i < PE_SECTION_TABLE_SIZE; i++) { section_data[i].vma_offset += ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile)); } /* Truncate name at first dot. Should maybe also convert to all lower case for convenience on Windows. */ read_pe_truncate_name (dll_name); /* Iterate through the list of symbols. */ for (i = 0; i < nexp; i++) { /* Pointer to the names vector. */ unsigned long name_rva = pe_as32 (erva + name_rvas + i * 4); /* Pointer to the function address vector. */ unsigned long func_rva = pe_as32 (erva + exp_funcbase + i * 4); /* Find this symbol's section in our own array. */ int sectix = 0; for (sectix = 0; sectix < PE_SECTION_TABLE_SIZE; ++sectix) { if ((func_rva >= section_data[sectix].rva_start) && (func_rva < section_data[sectix].rva_end)) { add_pe_exported_sym (erva + name_rva, func_rva, section_data + sectix, dll_name, objfile); break; } } } /* Discard expdata. */ do_cleanups (back_to); }