1/* Read the export table symbols from a portable executable and 2 convert to internal format, for GDB. Used as a last resort if no 3 debugging symbols recognized. 4 5 Copyright (C) 2003, 2007 Free Software Foundation, Inc. 6 7 This file is part of GDB. 8 9 This program is free software; you can redistribute it and/or modify 10 it under the terms of the GNU General Public License as published by 11 the Free Software Foundation; either version 3 of the License, or 12 (at your option) any later version. 13 14 This program is distributed in the hope that it will be useful, 15 but WITHOUT ANY WARRANTY; without even the implied warranty of 16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 GNU General Public License for more details. 18 19 You should have received a copy of the GNU General Public License 20 along with this program. If not, see <http://www.gnu.org/licenses/>. 21 22 Contributed by Raoul M. Gough (RaoulGough@yahoo.co.uk). */ 23 24#include "coff-pe-read.h" 25 26#include "bfd.h" 27 28#include "defs.h" 29#include "gdbtypes.h" 30 31#include "symtab.h" 32#include "symfile.h" 33#include "objfiles.h" 34 35/* Internal section information */ 36 37struct read_pe_section_data 38{ 39 CORE_ADDR vma_offset; /* Offset to loaded address of section. */ 40 unsigned long rva_start; /* Start offset within the pe. */ 41 unsigned long rva_end; /* End offset within the pe. */ 42 enum minimal_symbol_type ms_type; /* Type to assign symbols in section. */ 43}; 44 45#define PE_SECTION_INDEX_TEXT 0 46#define PE_SECTION_INDEX_DATA 1 47#define PE_SECTION_INDEX_BSS 2 48#define PE_SECTION_TABLE_SIZE 3 49#define PE_SECTION_INDEX_INVALID -1 50 51/* Get the index of the named section in our own array, which contains 52 text, data and bss in that order. Return PE_SECTION_INDEX_INVALID 53 if passed an unrecognised section name. */ 54 55static int 56read_pe_section_index (const char *section_name) 57{ 58 if (strcmp (section_name, ".text") == 0) 59 { 60 return PE_SECTION_INDEX_TEXT; 61 } 62 63 else if (strcmp (section_name, ".data") == 0) 64 { 65 return PE_SECTION_INDEX_DATA; 66 } 67 68 else if (strcmp (section_name, ".bss") == 0) 69 { 70 return PE_SECTION_INDEX_BSS; 71 } 72 73 else 74 { 75 return PE_SECTION_INDEX_INVALID; 76 } 77} 78 79/* Record the virtual memory address of a section. */ 80 81static void 82get_section_vmas (bfd *abfd, asection *sectp, void *context) 83{ 84 struct read_pe_section_data *sections = context; 85 int sectix = read_pe_section_index (sectp->name); 86 87 if (sectix != PE_SECTION_INDEX_INVALID) 88 { 89 /* Data within the section start at rva_start in the pe and at 90 bfd_get_section_vma() within memory. Store the offset. */ 91 92 sections[sectix].vma_offset 93 = bfd_get_section_vma (abfd, sectp) - sections[sectix].rva_start; 94 } 95} 96 97/* Create a minimal symbol entry for an exported symbol. */ 98 99static void 100add_pe_exported_sym (char *sym_name, 101 unsigned long func_rva, 102 const struct read_pe_section_data *section_data, 103 const char *dll_name, struct objfile *objfile) 104{ 105 /* Add the stored offset to get the loaded address of the symbol. */ 106 107 CORE_ADDR vma = func_rva + section_data->vma_offset; 108 109 char *qualified_name = 0; 110 int dll_name_len = strlen (dll_name); 111 int count; 112 113 /* Generate a (hopefully unique) qualified name using the first part 114 of the dll name, e.g. KERNEL32!AddAtomA. This matches the style 115 used by windbg from the "Microsoft Debugging Tools for Windows". */ 116 117 qualified_name = xmalloc (dll_name_len + strlen (sym_name) + 2); 118 119 strncpy (qualified_name, dll_name, dll_name_len); 120 qualified_name[dll_name_len] = '!'; 121 strcpy (qualified_name + dll_name_len + 1, sym_name); 122 123 prim_record_minimal_symbol (qualified_name, 124 vma, section_data->ms_type, objfile); 125 126 xfree (qualified_name); 127 128 /* Enter the plain name as well, which might not be unique. */ 129 prim_record_minimal_symbol (sym_name, vma, section_data->ms_type, objfile); 130} 131 132/* Truncate a dll_name at the first dot character. */ 133 134static void 135read_pe_truncate_name (char *dll_name) 136{ 137 while (*dll_name) 138 { 139 if ((*dll_name) == '.') 140 { 141 *dll_name = '\0'; /* truncates and causes loop exit. */ 142 } 143 144 else 145 { 146 ++dll_name; 147 } 148 } 149} 150 151/* Low-level support functions, direct from the ld module pe-dll.c. */ 152static unsigned int 153pe_get16 (bfd *abfd, int where) 154{ 155 unsigned char b[2]; 156 157 bfd_seek (abfd, (file_ptr) where, SEEK_SET); 158 bfd_bread (b, (bfd_size_type) 2, abfd); 159 return b[0] + (b[1] << 8); 160} 161 162static unsigned int 163pe_get32 (bfd *abfd, int where) 164{ 165 unsigned char b[4]; 166 167 bfd_seek (abfd, (file_ptr) where, SEEK_SET); 168 bfd_bread (b, (bfd_size_type) 4, abfd); 169 return b[0] + (b[1] << 8) + (b[2] << 16) + (b[3] << 24); 170} 171 172static unsigned int 173pe_as32 (void *ptr) 174{ 175 unsigned char *b = ptr; 176 177 return b[0] + (b[1] << 8) + (b[2] << 16) + (b[3] << 24); 178} 179 180/* Read the (non-debug) export symbol table from a portable 181 executable. Code originally lifted from the ld function 182 pe_implied_import_dll in pe-dll.c. */ 183 184void 185read_pe_exported_syms (struct objfile *objfile) 186{ 187 bfd *dll = objfile->obfd; 188 unsigned long pe_header_offset, opthdr_ofs, num_entries, i; 189 unsigned long export_rva, export_size, nsections, secptr, expptr; 190 unsigned long exp_funcbase; 191 unsigned char *expdata, *erva; 192 unsigned long name_rvas, ordinals, nexp, ordbase; 193 char *dll_name; 194 195 /* Array elements are for text, data and bss in that order 196 Initialization with start_rva > end_rva guarantees that 197 unused sections won't be matched. */ 198 struct read_pe_section_data section_data[PE_SECTION_TABLE_SIZE] 199 = { {0, 1, 0, mst_text}, 200 {0, 1, 0, mst_data}, 201 {0, 1, 0, mst_bss} 202 }; 203 204 struct cleanup *back_to = 0; 205 206 char const *target = bfd_get_target (objfile->obfd); 207 208 if ((strcmp (target, "pe-i386") != 0) && (strcmp (target, "pei-i386") != 0)) 209 { 210 /* This is not an i386 format file. Abort now, because the code 211 is untested on anything else. *FIXME* test on further 212 architectures and loosen or remove this test. */ 213 return; 214 } 215 216 /* Get pe_header, optional header and numbers of export entries. */ 217 pe_header_offset = pe_get32 (dll, 0x3c); 218 opthdr_ofs = pe_header_offset + 4 + 20; 219 num_entries = pe_get32 (dll, opthdr_ofs + 92); 220 221 if (num_entries < 1) /* No exports. */ 222 { 223 return; 224 } 225 226 export_rva = pe_get32 (dll, opthdr_ofs + 96); 227 export_size = pe_get32 (dll, opthdr_ofs + 100); 228 nsections = pe_get16 (dll, pe_header_offset + 4 + 2); 229 secptr = (pe_header_offset + 4 + 20 + 230 pe_get16 (dll, pe_header_offset + 4 + 16)); 231 expptr = 0; 232 233 /* Get the rva and size of the export section. */ 234 for (i = 0; i < nsections; i++) 235 { 236 char sname[8]; 237 unsigned long secptr1 = secptr + 40 * i; 238 unsigned long vaddr = pe_get32 (dll, secptr1 + 12); 239 unsigned long vsize = pe_get32 (dll, secptr1 + 16); 240 unsigned long fptr = pe_get32 (dll, secptr1 + 20); 241 242 bfd_seek (dll, (file_ptr) secptr1, SEEK_SET); 243 bfd_bread (sname, (bfd_size_type) 8, dll); 244 245 if (vaddr <= export_rva && vaddr + vsize > export_rva) 246 { 247 expptr = fptr + (export_rva - vaddr); 248 if (export_rva + export_size > vaddr + vsize) 249 export_size = vsize - (export_rva - vaddr); 250 break; 251 } 252 } 253 254 if (export_size == 0) 255 { 256 /* Empty export table. */ 257 return; 258 } 259 260 /* Scan sections and store the base and size of the relevant sections. */ 261 for (i = 0; i < nsections; i++) 262 { 263 unsigned long secptr1 = secptr + 40 * i; 264 unsigned long vsize = pe_get32 (dll, secptr1 + 8); 265 unsigned long vaddr = pe_get32 (dll, secptr1 + 12); 266 unsigned long flags = pe_get32 (dll, secptr1 + 36); 267 char sec_name[9]; 268 int sectix; 269 270 sec_name[8] = '\0'; 271 bfd_seek (dll, (file_ptr) secptr1 + 0, SEEK_SET); 272 bfd_bread (sec_name, (bfd_size_type) 8, dll); 273 274 sectix = read_pe_section_index (sec_name); 275 276 if (sectix != PE_SECTION_INDEX_INVALID) 277 { 278 section_data[sectix].rva_start = vaddr; 279 section_data[sectix].rva_end = vaddr + vsize; 280 } 281 } 282 283 expdata = (unsigned char *) xmalloc (export_size); 284 back_to = make_cleanup (xfree, expdata); 285 286 bfd_seek (dll, (file_ptr) expptr, SEEK_SET); 287 bfd_bread (expdata, (bfd_size_type) export_size, dll); 288 erva = expdata - export_rva; 289 290 nexp = pe_as32 (expdata + 24); 291 name_rvas = pe_as32 (expdata + 32); 292 ordinals = pe_as32 (expdata + 36); 293 ordbase = pe_as32 (expdata + 16); 294 exp_funcbase = pe_as32 (expdata + 28); 295 296 /* Use internal dll name instead of full pathname. */ 297 dll_name = pe_as32 (expdata + 12) + erva; 298 299 bfd_map_over_sections (dll, get_section_vmas, section_data); 300 301 /* Adjust the vma_offsets in case this PE got relocated. This 302 assumes that *all* sections share the same relocation offset 303 as the text section. */ 304 for (i = 0; i < PE_SECTION_TABLE_SIZE; i++) 305 { 306 section_data[i].vma_offset 307 += ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile)); 308 } 309 310 /* Truncate name at first dot. Should maybe also convert to all 311 lower case for convenience on Windows. */ 312 read_pe_truncate_name (dll_name); 313 314 /* Iterate through the list of symbols. */ 315 for (i = 0; i < nexp; i++) 316 { 317 /* Pointer to the names vector. */ 318 unsigned long name_rva = pe_as32 (erva + name_rvas + i * 4); 319 320 /* Pointer to the function address vector. */ 321 unsigned long func_rva = pe_as32 (erva + exp_funcbase + i * 4); 322 323 /* Find this symbol's section in our own array. */ 324 int sectix = 0; 325 326 for (sectix = 0; sectix < PE_SECTION_TABLE_SIZE; ++sectix) 327 { 328 if ((func_rva >= section_data[sectix].rva_start) 329 && (func_rva < section_data[sectix].rva_end)) 330 { 331 add_pe_exported_sym (erva + name_rva, 332 func_rva, 333 section_data + sectix, dll_name, objfile); 334 break; 335 } 336 } 337 } 338 339 /* discard expdata. */ 340 do_cleanups (back_to); 341} 342