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, 2008, 2009 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 37 struct 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 55 static int 56 read_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 81 static void 82 get_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 99 static void 100 add_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. */ 133 134 static void 135 read_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. */ 152 static unsigned int 153 pe_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 } 161 162 static unsigned int 163 pe_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 } 171 172 static unsigned int 173 pe_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. */ 183 184 void 185 read_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 int is_pe64 = 0; 195 int is_pe32 = 0; 196 197 /* Array elements are for text, data and bss in that order 198 Initialization with start_rva > end_rva guarantees that 199 unused sections won't be matched. */ 200 struct read_pe_section_data section_data[PE_SECTION_TABLE_SIZE] 201 = { {0, 1, 0, mst_text}, 202 {0, 1, 0, mst_data}, 203 {0, 1, 0, mst_bss} 204 }; 205 206 struct cleanup *back_to = 0; 207 208 char const *target = bfd_get_target (objfile->obfd); 209 210 is_pe64 = (strcmp (target, "pe-x86-64") == 0 211 || strcmp (target, "pei-x86-64") == 0); 212 is_pe32 = (strcmp (target, "pe-i386") == 0 213 || strcmp (target, "pei-i386") == 0 214 || strcmp (target, "pe-arm-wince-little") == 0 215 || strcmp (target, "pei-arm-wince-little") == 0); 216 217 if (!is_pe32 && !is_pe64) 218 { 219 /* This is not a recognized PE format file. Abort now, because 220 the code is untested on anything else. *FIXME* test on 221 further architectures and loosen or remove this test. */ 222 return; 223 } 224 225 /* Get pe_header, optional header and numbers of export entries. */ 226 pe_header_offset = pe_get32 (dll, 0x3c); 227 opthdr_ofs = pe_header_offset + 4 + 20; 228 if (is_pe64) 229 num_entries = pe_get32 (dll, opthdr_ofs + 108); 230 else 231 num_entries = pe_get32 (dll, opthdr_ofs + 92); 232 233 if (num_entries < 1) /* No exports. */ 234 { 235 return; 236 } 237 238 if (is_pe64) 239 { 240 export_rva = pe_get32 (dll, opthdr_ofs + 112); 241 export_size = pe_get32 (dll, opthdr_ofs + 116); 242 } 243 else 244 { 245 export_rva = pe_get32 (dll, opthdr_ofs + 96); 246 export_size = pe_get32 (dll, opthdr_ofs + 100); 247 } 248 nsections = pe_get16 (dll, pe_header_offset + 4 + 2); 249 secptr = (pe_header_offset + 4 + 20 + 250 pe_get16 (dll, pe_header_offset + 4 + 16)); 251 expptr = 0; 252 253 /* Get the rva and size of the export section. */ 254 for (i = 0; i < nsections; i++) 255 { 256 char sname[8]; 257 unsigned long secptr1 = secptr + 40 * i; 258 unsigned long vaddr = pe_get32 (dll, secptr1 + 12); 259 unsigned long vsize = pe_get32 (dll, secptr1 + 16); 260 unsigned long fptr = pe_get32 (dll, secptr1 + 20); 261 262 bfd_seek (dll, (file_ptr) secptr1, SEEK_SET); 263 bfd_bread (sname, (bfd_size_type) 8, dll); 264 265 if (vaddr <= export_rva && vaddr + vsize > export_rva) 266 { 267 expptr = fptr + (export_rva - vaddr); 268 if (export_rva + export_size > vaddr + vsize) 269 export_size = vsize - (export_rva - vaddr); 270 break; 271 } 272 } 273 274 if (export_size == 0) 275 { 276 /* Empty export table. */ 277 return; 278 } 279 280 /* Scan sections and store the base and size of the relevant sections. */ 281 for (i = 0; i < nsections; i++) 282 { 283 unsigned long secptr1 = secptr + 40 * i; 284 unsigned long vsize = pe_get32 (dll, secptr1 + 8); 285 unsigned long vaddr = pe_get32 (dll, secptr1 + 12); 286 unsigned long flags = pe_get32 (dll, secptr1 + 36); 287 char sec_name[9]; 288 int sectix; 289 290 sec_name[8] = '\0'; 291 bfd_seek (dll, (file_ptr) secptr1 + 0, SEEK_SET); 292 bfd_bread (sec_name, (bfd_size_type) 8, dll); 293 294 sectix = read_pe_section_index (sec_name); 295 296 if (sectix != PE_SECTION_INDEX_INVALID) 297 { 298 section_data[sectix].rva_start = vaddr; 299 section_data[sectix].rva_end = vaddr + vsize; 300 } 301 } 302 303 expdata = (unsigned char *) xmalloc (export_size); 304 back_to = make_cleanup (xfree, expdata); 305 306 bfd_seek (dll, (file_ptr) expptr, SEEK_SET); 307 bfd_bread (expdata, (bfd_size_type) export_size, dll); 308 erva = expdata - export_rva; 309 310 nexp = pe_as32 (expdata + 24); 311 name_rvas = pe_as32 (expdata + 32); 312 ordinals = pe_as32 (expdata + 36); 313 ordbase = pe_as32 (expdata + 16); 314 exp_funcbase = pe_as32 (expdata + 28); 315 316 /* Use internal dll name instead of full pathname. */ 317 dll_name = pe_as32 (expdata + 12) + erva; 318 319 bfd_map_over_sections (dll, get_section_vmas, section_data); 320 321 /* Adjust the vma_offsets in case this PE got relocated. This 322 assumes that *all* sections share the same relocation offset 323 as the text section. */ 324 for (i = 0; i < PE_SECTION_TABLE_SIZE; i++) 325 { 326 section_data[i].vma_offset 327 += ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile)); 328 } 329 330 /* Truncate name at first dot. Should maybe also convert to all 331 lower case for convenience on Windows. */ 332 read_pe_truncate_name (dll_name); 333 334 /* Iterate through the list of symbols. */ 335 for (i = 0; i < nexp; i++) 336 { 337 /* Pointer to the names vector. */ 338 unsigned long name_rva = pe_as32 (erva + name_rvas + i * 4); 339 340 /* Pointer to the function address vector. */ 341 unsigned long func_rva = pe_as32 (erva + exp_funcbase + i * 4); 342 343 /* Find this symbol's section in our own array. */ 344 int sectix = 0; 345 346 for (sectix = 0; sectix < PE_SECTION_TABLE_SIZE; ++sectix) 347 { 348 if ((func_rva >= section_data[sectix].rva_start) 349 && (func_rva < section_data[sectix].rva_end)) 350 { 351 add_pe_exported_sym (erva + name_rva, 352 func_rva, 353 section_data + sectix, dll_name, objfile); 354 break; 355 } 356 } 357 } 358 359 /* discard expdata. */ 360 do_cleanups (back_to); 361 } 362