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.
5 Copyright (C) 2003-2014 Free Software Foundation, Inc.
7 This file is part of GDB.
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.
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.
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/>.
22 Contributed by Raoul M. Gough (RaoulGough@yahoo.co.uk). */
26 #include "coff-pe-read.h"
36 #include "common/common-utils.h"
37 #include "coff/internal.h"
41 /* Internal section information */
43 /* Coff PE read debugging flag:
45 value 1 outputs problems encountered while parsing PE file,
46 value above 1 also lists all generated minimal symbols. */
47 static unsigned int debug_coff_pe_read;
49 struct read_pe_section_data
51 CORE_ADDR vma_offset; /* Offset to loaded address of section. */
52 unsigned long rva_start; /* Start offset within the pe. */
53 unsigned long rva_end; /* End offset within the pe. */
54 enum minimal_symbol_type ms_type; /* Type to assign symbols in
56 unsigned int index; /* BFD section number. */
57 char *section_name; /* Recorded section name. */
60 #define IMAGE_SCN_CNT_CODE 0x20
61 #define IMAGE_SCN_CNT_INITIALIZED_DATA 0x40
62 #define IMAGE_SCN_CNT_UNINITIALIZED_DATA 0x80
63 #define PE_SECTION_INDEX_TEXT 0
64 #define PE_SECTION_INDEX_DATA 1
65 #define PE_SECTION_INDEX_BSS 2
66 #define PE_SECTION_TABLE_SIZE 3
67 #define PE_SECTION_INDEX_INVALID -1
69 /* Get the index of the named section in our own array, which contains
70 text, data and bss in that order. Return PE_SECTION_INDEX_INVALID
71 if passed an unrecognised section name. */
74 read_pe_section_index (const char *section_name)
76 if (strcmp (section_name, ".text") == 0)
78 return PE_SECTION_INDEX_TEXT;
81 else if (strcmp (section_name, ".data") == 0)
83 return PE_SECTION_INDEX_DATA;
86 else if (strcmp (section_name, ".bss") == 0)
88 return PE_SECTION_INDEX_BSS;
93 return PE_SECTION_INDEX_INVALID;
97 /* Get the index of the named section in our own full array.
98 text, data and bss in that order. Return PE_SECTION_INDEX_INVALID
99 if passed an unrecognised section name. */
102 get_pe_section_index (const char *section_name,
103 struct read_pe_section_data *sections,
108 for (i = 0; i < nb_sections; i++)
109 if (strcmp (sections[i].section_name, section_name) == 0)
111 return PE_SECTION_INDEX_INVALID;
114 /* Structure used by get_section_vmas function below
115 to access section_data array and the size of the array
116 stored in nb_sections field. */
117 struct pe_sections_info
120 struct read_pe_section_data *sections;
123 /* Record the virtual memory address of a section. */
126 get_section_vmas (bfd *abfd, asection *sectp, void *context)
128 struct pe_sections_info *data = context;
129 struct read_pe_section_data *sections = data->sections;
130 int sectix = get_pe_section_index (sectp->name, sections,
133 if (sectix != PE_SECTION_INDEX_INVALID)
135 /* Data within the section start at rva_start in the pe and at
136 bfd_get_section_vma() within memory. Store the offset. */
138 sections[sectix].vma_offset
139 = bfd_get_section_vma (abfd, sectp) - sections[sectix].rva_start;
143 /* Create a minimal symbol entry for an exported symbol.
144 SYM_NAME contains the exported name or NULL if exported by ordinal,
145 FUNC_RVA contains the Relative Virtual Address of the symbol,
146 ORDINAL is the ordinal index value of the symbol,
147 SECTION_DATA contains information about the section in which the
149 DLL_NAME is the internal name of the DLL file,
150 OBJFILE is the objfile struct of DLL_NAME. */
153 add_pe_exported_sym (const char *sym_name,
154 unsigned long func_rva,
156 const struct read_pe_section_data *section_data,
157 const char *dll_name, struct objfile *objfile)
159 char *qualified_name, *bare_name;
160 /* Add the stored offset to get the loaded address of the symbol. */
161 CORE_ADDR vma = func_rva + section_data->vma_offset;
163 /* Generate a (hopefully unique) qualified name using the first part
164 of the dll name, e.g. KERNEL32!AddAtomA. This matches the style
165 used by windbg from the "Microsoft Debugging Tools for Windows". */
167 if (sym_name == NULL || *sym_name == '\0')
168 bare_name = xstrprintf ("#%d", ordinal);
170 bare_name = xstrdup (sym_name);
172 qualified_name = xstrprintf ("%s!%s", dll_name, bare_name);
174 if ((section_data->ms_type == mst_unknown) && debug_coff_pe_read)
175 fprintf_unfiltered (gdb_stdlog , _("Unknown section type for \"%s\""
176 " for entry \"%s\" in dll \"%s\"\n"),
177 section_data->section_name, sym_name, dll_name);
179 prim_record_minimal_symbol_and_info (qualified_name, vma,
180 section_data->ms_type,
181 section_data->index, objfile);
183 /* Enter the plain name as well, which might not be unique. */
184 prim_record_minimal_symbol_and_info (bare_name, vma, section_data->ms_type,
185 section_data->index, objfile);
186 if (debug_coff_pe_read > 1)
187 fprintf_unfiltered (gdb_stdlog, _("Adding exported symbol \"%s\""
188 " in dll \"%s\"\n"), sym_name, dll_name);
189 xfree (qualified_name);
193 /* Create a minimal symbol entry for an exported forward symbol.
194 Return 1 if the forwarded function was found 0 otherwise.
195 SYM_NAME contains the exported name or NULL if exported by ordinal,
196 FORWARD_DLL_NAME is the name of the DLL in which the target symobl resides,
197 FORWARD_FUNC_NAME is the name of the target symbol in that DLL,
198 ORDINAL is the ordinal index value of the symbol,
199 DLL_NAME is the internal name of the DLL file,
200 OBJFILE is the objfile struct of DLL_NAME. */
203 add_pe_forwarded_sym (const char *sym_name, const char *forward_dll_name,
204 const char *forward_func_name, int ordinal,
205 const char *dll_name, struct objfile *objfile)
207 CORE_ADDR vma, baseaddr;
208 struct bound_minimal_symbol msymbol;
209 enum minimal_symbol_type msymtype;
210 char *qualified_name, *bare_name;
211 int forward_dll_name_len = strlen (forward_dll_name);
212 int forward_func_name_len = strlen (forward_func_name);
213 int forward_len = forward_dll_name_len + forward_func_name_len + 2;
214 char *forward_qualified_name = alloca (forward_len);
217 xsnprintf (forward_qualified_name, forward_len, "%s!%s", forward_dll_name,
221 msymbol = lookup_minimal_symbol_and_objfile (forward_qualified_name);
227 for (i = 0; i < forward_dll_name_len; i++)
228 forward_qualified_name[i] = tolower (forward_qualified_name[i]);
229 msymbol = lookup_minimal_symbol_and_objfile (forward_qualified_name);
234 if (debug_coff_pe_read)
235 fprintf_unfiltered (gdb_stdlog, _("Unable to find function \"%s\" in"
236 " dll \"%s\", forward of \"%s\" in dll \"%s\"\n"),
237 forward_func_name, forward_dll_name, sym_name,
242 if (debug_coff_pe_read > 1)
243 fprintf_unfiltered (gdb_stdlog, _("Adding forwarded exported symbol"
244 " \"%s\" in dll \"%s\", pointing to \"%s\"\n"),
245 sym_name, dll_name, forward_qualified_name);
247 vma = BMSYMBOL_VALUE_ADDRESS (msymbol);
248 msymtype = MSYMBOL_TYPE (msymbol.minsym);
249 section = MSYMBOL_SECTION (msymbol.minsym);
251 /* Generate a (hopefully unique) qualified name using the first part
252 of the dll name, e.g. KERNEL32!AddAtomA. This matches the style
253 used by windbg from the "Microsoft Debugging Tools for Windows". */
255 if (sym_name == NULL || *sym_name == '\0')
256 bare_name = xstrprintf ("#%d", ordinal);
258 bare_name = xstrdup (sym_name);
260 qualified_name = xstrprintf ("%s!%s", dll_name, bare_name);
262 /* Note that this code makes a minimal symbol whose value may point
263 outside of any section in this objfile. These symbols can't
264 really be relocated properly, but nevertheless we make a stab at
265 it, choosing an approach consistent with the history of this
267 baseaddr = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
269 prim_record_minimal_symbol_and_info (qualified_name, vma - baseaddr,
270 msymtype, section, objfile);
272 /* Enter the plain name as well, which might not be unique. */
273 prim_record_minimal_symbol_and_info (bare_name, vma - baseaddr, msymtype,
275 xfree (qualified_name);
281 /* Truncate a dll_name at the last dot character. */
284 read_pe_truncate_name (char *dll_name)
286 char *last_point = strrchr (dll_name, '.');
288 if (last_point != NULL)
292 /* Low-level support functions, direct from the ld module pe-dll.c. */
294 pe_get16 (bfd *abfd, int where)
298 bfd_seek (abfd, (file_ptr) where, SEEK_SET);
299 bfd_bread (b, (bfd_size_type) 2, abfd);
300 return b[0] + (b[1] << 8);
304 pe_get32 (bfd *abfd, int where)
308 bfd_seek (abfd, (file_ptr) where, SEEK_SET);
309 bfd_bread (b, (bfd_size_type) 4, abfd);
310 return b[0] + (b[1] << 8) + (b[2] << 16) + (b[3] << 24);
316 unsigned char *b = ptr;
318 return b[0] + (b[1] << 8);
324 unsigned char *b = ptr;
326 return b[0] + (b[1] << 8) + (b[2] << 16) + (b[3] << 24);
329 /* Read the (non-debug) export symbol table from a portable
330 executable. Code originally lifted from the ld function
331 pe_implied_import_dll in pe-dll.c. */
334 read_pe_exported_syms (struct objfile *objfile)
336 bfd *dll = objfile->obfd;
337 unsigned long nbnormal, nbforward;
338 unsigned long pe_header_offset, opthdr_ofs, num_entries, i;
339 unsigned long export_opthdrrva, export_opthdrsize;
340 unsigned long export_rva, export_size, nsections, secptr, expptr;
341 unsigned long exp_funcbase;
342 unsigned char *expdata, *erva;
343 unsigned long name_rvas, ordinals, nexp, ordbase;
344 char *dll_name = (char *) dll->filename;
345 int otherix = PE_SECTION_TABLE_SIZE;
349 /* Array elements are for text, data and bss in that order
350 Initialization with RVA_START > RVA_END guarantees that
351 unused sections won't be matched. */
352 struct read_pe_section_data *section_data;
353 struct pe_sections_info pe_sections_info;
355 struct cleanup *back_to = make_cleanup (null_cleanup, 0);
357 char const *target = bfd_get_target (objfile->obfd);
359 section_data = xzalloc (PE_SECTION_TABLE_SIZE
360 * sizeof (struct read_pe_section_data));
362 make_cleanup (free_current_contents, §ion_data);
364 for (i=0; i < PE_SECTION_TABLE_SIZE; i++)
366 section_data[i].vma_offset = 0;
367 section_data[i].rva_start = 1;
368 section_data[i].rva_end = 0;
370 section_data[PE_SECTION_INDEX_TEXT].ms_type = mst_text;
371 section_data[PE_SECTION_INDEX_TEXT].section_name = ".text";
372 section_data[PE_SECTION_INDEX_DATA].ms_type = mst_data;
373 section_data[PE_SECTION_INDEX_DATA].section_name = ".data";
374 section_data[PE_SECTION_INDEX_BSS].ms_type = mst_bss;
375 section_data[PE_SECTION_INDEX_BSS].section_name = ".bss";
377 is_pe64 = (strcmp (target, "pe-x86-64") == 0
378 || strcmp (target, "pei-x86-64") == 0);
379 is_pe32 = (strcmp (target, "pe-i386") == 0
380 || strcmp (target, "pei-i386") == 0
381 || strcmp (target, "pe-arm-wince-little") == 0
382 || strcmp (target, "pei-arm-wince-little") == 0);
383 if (!is_pe32 && !is_pe64)
385 /* This is not a recognized PE format file. Abort now, because
386 the code is untested on anything else. *FIXME* test on
387 further architectures and loosen or remove this test. */
388 do_cleanups (back_to);
392 /* Get pe_header, optional header and numbers of export entries. */
393 pe_header_offset = pe_get32 (dll, 0x3c);
394 opthdr_ofs = pe_header_offset + 4 + 20;
396 num_entries = pe_get32 (dll, opthdr_ofs + 108);
398 num_entries = pe_get32 (dll, opthdr_ofs + 92);
400 if (num_entries < 1) /* No exports. */
402 do_cleanups (back_to);
407 export_opthdrrva = pe_get32 (dll, opthdr_ofs + 112);
408 export_opthdrsize = pe_get32 (dll, opthdr_ofs + 116);
412 export_opthdrrva = pe_get32 (dll, opthdr_ofs + 96);
413 export_opthdrsize = pe_get32 (dll, opthdr_ofs + 100);
415 nsections = pe_get16 (dll, pe_header_offset + 4 + 2);
416 secptr = (pe_header_offset + 4 + 20 +
417 pe_get16 (dll, pe_header_offset + 4 + 16));
421 /* Get the rva and size of the export section. */
422 for (i = 0; i < nsections; i++)
425 unsigned long secptr1 = secptr + 40 * i;
426 unsigned long vaddr = pe_get32 (dll, secptr1 + 12);
427 unsigned long vsize = pe_get32 (dll, secptr1 + 16);
428 unsigned long fptr = pe_get32 (dll, secptr1 + 20);
430 bfd_seek (dll, (file_ptr) secptr1, SEEK_SET);
431 bfd_bread (sname, (bfd_size_type) sizeof (sname), dll);
433 if ((strcmp (sname, ".edata") == 0)
434 || (vaddr <= export_opthdrrva && export_opthdrrva < vaddr + vsize))
436 if (strcmp (sname, ".edata") != 0)
438 if (debug_coff_pe_read)
439 fprintf_unfiltered (gdb_stdlog, _("Export RVA for dll "
440 "\"%s\" is in section \"%s\"\n"),
443 else if (export_opthdrrva != vaddr && debug_coff_pe_read)
444 fprintf_unfiltered (gdb_stdlog, _("Wrong value of export RVA"
445 " for dll \"%s\": 0x%lx instead of 0x%lx\n"),
446 dll_name, export_opthdrrva, vaddr);
447 expptr = fptr + (export_opthdrrva - vaddr);
452 export_rva = export_opthdrrva;
453 export_size = export_opthdrsize;
455 if (export_size == 0)
457 /* Empty export table. */
458 do_cleanups (back_to);
462 /* Scan sections and store the base and size of the relevant
464 for (i = 0; i < nsections; i++)
466 unsigned long secptr1 = secptr + 40 * i;
467 unsigned long vsize = pe_get32 (dll, secptr1 + 8);
468 unsigned long vaddr = pe_get32 (dll, secptr1 + 12);
469 unsigned long characteristics = pe_get32 (dll, secptr1 + 36);
470 char sec_name[SCNNMLEN + 1];
472 unsigned int bfd_section_index;
475 bfd_seek (dll, (file_ptr) secptr1 + 0, SEEK_SET);
476 bfd_bread (sec_name, (bfd_size_type) SCNNMLEN, dll);
477 sec_name[SCNNMLEN] = '\0';
479 sectix = read_pe_section_index (sec_name);
480 section = bfd_get_section_by_name (dll, sec_name);
482 bfd_section_index = section->index;
484 bfd_section_index = -1;
486 if (sectix != PE_SECTION_INDEX_INVALID)
488 section_data[sectix].rva_start = vaddr;
489 section_data[sectix].rva_end = vaddr + vsize;
490 section_data[sectix].index = bfd_section_index;
496 section_data = xrealloc (section_data, (otherix + 1)
497 * sizeof (struct read_pe_section_data));
498 name = xstrdup (sec_name);
499 section_data[otherix].section_name = name;
500 make_cleanup (xfree, name);
501 section_data[otherix].rva_start = vaddr;
502 section_data[otherix].rva_end = vaddr + vsize;
503 section_data[otherix].vma_offset = 0;
504 section_data[otherix].index = bfd_section_index;
505 if (characteristics & IMAGE_SCN_CNT_CODE)
506 section_data[otherix].ms_type = mst_text;
507 else if (characteristics & IMAGE_SCN_CNT_INITIALIZED_DATA)
508 section_data[otherix].ms_type = mst_data;
509 else if (characteristics & IMAGE_SCN_CNT_UNINITIALIZED_DATA)
510 section_data[otherix].ms_type = mst_bss;
512 section_data[otherix].ms_type = mst_unknown;
517 expdata = (unsigned char *) xmalloc (export_size);
518 make_cleanup (xfree, expdata);
520 bfd_seek (dll, (file_ptr) expptr, SEEK_SET);
521 bfd_bread (expdata, (bfd_size_type) export_size, dll);
522 erva = expdata - export_rva;
524 nexp = pe_as32 (expdata + 24);
525 name_rvas = pe_as32 (expdata + 32);
526 ordinals = pe_as32 (expdata + 36);
527 ordbase = pe_as32 (expdata + 16);
528 exp_funcbase = pe_as32 (expdata + 28);
530 /* Use internal dll name instead of full pathname. */
531 dll_name = (char *) (pe_as32 (expdata + 12) + erva);
533 pe_sections_info.nb_sections = otherix;
534 pe_sections_info.sections = section_data;
536 bfd_map_over_sections (dll, get_section_vmas, &pe_sections_info);
538 /* Truncate name at first dot. Should maybe also convert to all
539 lower case for convenience on Windows. */
540 read_pe_truncate_name (dll_name);
542 if (debug_coff_pe_read)
543 fprintf_unfiltered (gdb_stdlog, _("DLL \"%s\" has %ld export entries,"
544 " base=%ld\n"), dll_name, nexp, ordbase);
547 /* Iterate through the list of symbols. */
548 for (i = 0; i < nexp; i++)
550 /* Pointer to the names vector. */
551 unsigned long name_rva = pe_as32 (erva + name_rvas + i * 4);
552 /* Retrieve ordinal value. */
554 unsigned long ordinal = pe_as16 (erva + ordinals + i * 2);
557 /* Pointer to the function address vector. */
558 /* This is relatived to ordinal value. */
559 unsigned long func_rva = pe_as32 (erva + exp_funcbase +
562 /* Find this symbol's section in our own array. */
564 int section_found = 0;
566 /* First handle forward cases. */
567 if (func_rva >= export_rva && func_rva < export_rva + export_size)
569 char *forward_name = (char *) (erva + func_rva);
570 char *funcname = (char *) (erva + name_rva);
571 char *forward_dll_name = forward_name;
572 char *forward_func_name = forward_name;
573 char *sep = strrchr (forward_name, '.');
577 int len = (int) (sep - forward_name);
579 forward_dll_name = alloca (len + 1);
580 strncpy (forward_dll_name, forward_name, len);
581 forward_dll_name[len] = '\0';
582 forward_func_name = ++sep;
584 if (add_pe_forwarded_sym (funcname, forward_dll_name,
585 forward_func_name, ordinal,
586 dll_name, objfile) != 0)
591 for (sectix = 0; sectix < otherix; ++sectix)
593 if ((func_rva >= section_data[sectix].rva_start)
594 && (func_rva < section_data[sectix].rva_end))
596 char *sym_name = (char *) (erva + name_rva);
599 add_pe_exported_sym (sym_name, func_rva, ordinal,
600 section_data + sectix, dll_name, objfile);
607 char *funcname = (char *) (erva + name_rva);
611 add_pe_exported_sym (NULL, func_rva, ordinal,
612 section_data, dll_name, objfile);
615 else if (debug_coff_pe_read)
616 fprintf_unfiltered (gdb_stdlog, _("Export name \"%s\" ord. %lu,"
617 " RVA 0x%lx in dll \"%s\" not handled\n"),
618 funcname, ordinal, func_rva, dll_name);
622 if (debug_coff_pe_read)
623 fprintf_unfiltered (gdb_stdlog, _("Finished reading \"%s\", exports %ld,"
624 " forwards %ld, total %ld/%ld.\n"), dll_name, nbnormal,
625 nbforward, nbnormal + nbforward, nexp);
626 /* Discard expdata and section_data. */
627 do_cleanups (back_to);
630 /* Extract from ABFD the offset of the .text section.
631 This offset is mainly related to the offset within the file.
632 The value was previously expected to be 0x1000 for all files,
633 but some Windows OS core DLLs seem to use 0x10000 section alignement
634 which modified the return value of that function.
635 Still return default 0x1000 value if ABFD is NULL or
636 if '.text' section is not found, but that should not happen... */
638 #define DEFAULT_COFF_PE_TEXT_SECTION_OFFSET 0x1000
641 pe_text_section_offset (struct bfd *abfd)
644 unsigned long pe_header_offset, i;
645 unsigned long nsections, secptr;
651 return DEFAULT_COFF_PE_TEXT_SECTION_OFFSET;
653 target = bfd_get_target (abfd);
655 is_pe64 = (strcmp (target, "pe-x86-64") == 0
656 || strcmp (target, "pei-x86-64") == 0);
657 is_pe32 = (strcmp (target, "pe-i386") == 0
658 || strcmp (target, "pei-i386") == 0
659 || strcmp (target, "pe-arm-wince-little") == 0
660 || strcmp (target, "pei-arm-wince-little") == 0);
662 if (!is_pe32 && !is_pe64)
664 /* This is not a recognized PE format file. Abort now, because
665 the code is untested on anything else. *FIXME* test on
666 further architectures and loosen or remove this test. */
667 return DEFAULT_COFF_PE_TEXT_SECTION_OFFSET;
670 /* Get pe_header, optional header and numbers of sections. */
671 pe_header_offset = pe_get32 (abfd, 0x3c);
672 nsections = pe_get16 (abfd, pe_header_offset + 4 + 2);
673 secptr = (pe_header_offset + 4 + 20 +
674 pe_get16 (abfd, pe_header_offset + 4 + 16));
676 /* Get the rva and size of the export section. */
677 for (i = 0; i < nsections; i++)
679 char sname[SCNNMLEN + 1];
680 unsigned long secptr1 = secptr + 40 * i;
681 unsigned long vaddr = pe_get32 (abfd, secptr1 + 12);
683 bfd_seek (abfd, (file_ptr) secptr1, SEEK_SET);
684 bfd_bread (sname, (bfd_size_type) SCNNMLEN, abfd);
685 sname[SCNNMLEN] = '\0';
686 if (strcmp (sname, ".text") == 0)
690 return DEFAULT_COFF_PE_TEXT_SECTION_OFFSET;
693 /* Implements "show debug coff_pe_read" command. */
696 show_debug_coff_pe_read (struct ui_file *file, int from_tty,
697 struct cmd_list_element *c, const char *value)
699 fprintf_filtered (file, _("Coff PE read debugging is %s.\n"), value);
702 /* Provide a prototype to silence -Wmissing-prototypes. */
704 void _initialize_coff_pe_read (void);
706 /* Adds "Set/show debug coff_pe_read" commands. */
709 _initialize_coff_pe_read (void)
711 add_setshow_zuinteger_cmd ("coff-pe-read", class_maintenance,
713 _("Set coff PE read debugging."),
714 _("Show coff PE read debugging."),
715 _("When set, debugging messages for coff reading "
716 "of exported symbols are displayed."),
717 NULL, show_debug_coff_pe_read,
718 &setdebuglist, &showdebuglist);