[RFC-v5] Fix .text section offset for windows DLL (was Calling __stdcall functions in the inferior)

Pierre Muller
2012-11-27T14:59:01Z

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Thanks, Tom...
it really seems that this is the culprit:
I was freeing again already freed memory, which of course
created random crashes later.

I send here rapidly a new patch version.
I really tested the allocation problems by adding
allocation + free'ing of each of the first parameters
used in prim_record_minimal_symbol
and it does seem that freeing of char array doesn't lead to any problem.

So the only trouble was related to the
reallocation of section_data and seems to be fixed
thanks to Tom's proposal.

Yuanhui Zhang,
could you please check if the new patch
suppresses the crash you had when you tried the previous version?

Thanks to everyone...

Pierre Muller

2012-11-25 Pierre Muller <muller@sourceware.org>

* coff-pe-read.h (pe_text_section_offset): Declare new function.
* coff-pe-read.c (debug_coff_pe_read): New static variable.
(struct read_pe_section_data): Add section_name field.
(IMAGE_SCN_CNT_CODE): New macro, if not already defined.
(IMAGE_SCN_CNT_INITIALIZED_DATA): Ditto.
(IMAGE_SCN_CNT_UNINITIALIZED_DATA): Ditto.
(get_pe_section_index): New function.
(struct pe_sections_info): New type.
(get_section_vmas): Use new struct pe_sections_info.
(add_pe_exported_sym): Handle unnamed exported function.
(add_pe_forwarded_sym): New function.
(read_pe_truncate_name): Truncate at last dot.
(pe_as16): New function.
(read_pe_exported_syms): Use ordinal of function to
retrieve correct RVA address of function and handle
forwarded symbol.
(pe_text_section_offset): New function.
(show_debug_coff_pe_read): New function.
(_initialize_coff_pe_read): New function adding
'set/show debug coff_pe_read' commands.

* windows-tdep.c (windows_xfer_shared_library): Use
pe_text_section_offset function instead of possibly wrong
0x1000 constant for .text sextion offset.

> -----Message d'origine-----
> De : gdb-patches-owner@sourceware.org [mailto:gdb-patches-
> owner@sourceware.org] De la part de Tom Tromey
> Envoyé : lundi 26 novembre 2012 17:54
> À : Pierre Muller
> Cc : 'Joel Brobecker'; 'Pedro Alves'; 'Eli Zaretskii'; gdb-
> patches@sourceware.org
> Objet : Re: [RFC-v4] Fix .text section offset for windows DLL (was Calling
> __stdcall functions in the inferior)
>
> >>>>> "Pierre" == Pierre Muller <pierre.muller@ics-cnrs.unistra.fr>
writes:
>
> Joel> Are we missing a cleanup/xfree?
>
> Pierre> I added some, please check that part, as I have
> Pierre> no experience at all with using make_cleanup
> Pierre> related functions...
> Pierre> In particular, I didn't really get if it is OK to call
> Pierre> do_cleanups with a possibly NULL argument...
>
> The simplest way to approach cleanups, which I recommend in nearly all
> cases, is to treat them as block-scoped and to always pass the result of
> a make_cleanup call to do_cleanups. Try to avoid tricks with conditions
> and possibly-NULL cleanup pointers, this usually leads to trouble.
>
> Pierre> + struct cleanup *section_cleanup = 0;
>
> I think there's no need to initialize this, since you re-set it later.
>
> Pierre> + section_data = xzalloc (PE_SECTION_TABLE_SIZE
> Pierre> + * sizeof (struct read_pe_section_data));
> Pierre> +
> Pierre> + section_cleanup = make_cleanup (xfree, section_data);
>
> Ok so far, but...
>
> Pierre> + section_data = xrealloc (section_data, otherix
> Pierre> + * sizeof (struct
read_pe_section_data));
>
> ... this can free the original pointer.
>
> What you want is:
>
> section_cleanup = make_cleanup (free_current_contents, &section_data);
>
> This will free the current value of the pointer, instead of capturing
> the value when the cleanup is made.
>
> Pierre> /* Discard expdata. */
> Pierre> do_cleanups (back_to);
> Pierre> + /* Discard section_data. */
> Pierre> + do_cleanups (section_cleanup);
>
> Cleanups are a stack, so you can just invoke do_cleanups on the
> outermost one. Just delete the local variable 'back_to'.
>
> Tom

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2012-11-25 Pierre Muller <muller@sourceware.org>

* coff-pe-read.h (pe_text_section_offset): Declare new function.
* coff-pe-read.c (debug_coff_pe_read): New static variable.
(struct read_pe_section_data): Add section_name field.
(IMAGE_SCN_CNT_CODE): New macro, if not already defined.
(IMAGE_SCN_CNT_INITIALIZED_DATA): Ditto.
(IMAGE_SCN_CNT_UNINITIALIZED_DATA): Ditto.
(get_pe_section_index): New function.
(struct pe_sections_info): New type.
(get_section_vmas): Use new struct pe_sections_info.
(add_pe_exported_sym): Handle unnamed exported function.
(add_pe_forwarded_sym): New function.
(read_pe_truncate_name): Truncate at last dot.
(pe_as16): New function.
(read_pe_exported_syms): Use ordinal of function to
retrieve correct RVA address of function and handle
forwarded symbol.
(pe_text_section_offset): New function.
(show_debug_coff_pe_read): New function.
(_initialize_coff_pe_read): New function adding
'set/show debug coff_pe_read' commands.

* windows-tdep.c (windows_xfer_shared_library): Use
pe_text_section_offset function instead of possibly wrong
0x1000 constant for .text sextion offset.

Index: coff-pe-read.h
===================================================================
RCS file: /cvs/src/src/gdb/coff-pe-read.h,v
retrieving revision 1.11
diff -u -p -r1.11 coff-pe-read.h
--- coff-pe-read.h 4 Jan 2012 08:17:00 -0000 1.11
+++ coff-pe-read.h 27 Nov 2012 14:45:02 -0000
@@ -23,9 +23,14 @@
#define COFF_PE_READ_H

struct objfile;
+struct bfd;

/* Read the export table and convert it to minimal symbol table
entries */
extern void read_pe_exported_syms (struct objfile *objfile);

+/* Extract from ABFD the offset of the .text section.
+ Returns default value 0x1000 if information is not found. */
+extern CORE_ADDR pe_text_section_offset (struct bfd *abfd);
+
#endif /* !defined (COFF_PE_READ_H) */
Index: coff-pe-read.c
===================================================================
RCS file: /cvs/src/src/gdb/coff-pe-read.c,v
retrieving revision 1.18
diff -u -p -r1.18 coff-pe-read.c
--- coff-pe-read.c 7 Nov 2012 20:10:13 -0000 1.18
+++ coff-pe-read.c 27 Nov 2012 14:45:02 -0000
@@ -28,12 +28,23 @@
#include "bfd.h"
#include "gdbtypes.h"

+#include "command.h"
+#include "gdbcmd.h"
#include "symtab.h"
#include "symfile.h"
#include "objfiles.h"
+#include "common/common-utils.h"
+
+#include <ctype.h>

/* Internal section information */

+/* Coff PE read debugging flag:
+ default value is 0,
+ value 1 outputs problems encountered while parsing PE file,
+ value above 1 also lists all generated minimal symbols. */
+static unsigned int debug_coff_pe_read;
+
struct read_pe_section_data
{
CORE_ADDR vma_offset; /* Offset to loaded address of section. */
@@ -41,8 +52,18 @@ struct read_pe_section_data
unsigned long rva_end; /* End offset within the pe. */
enum minimal_symbol_type ms_type; /* Type to assign symbols in
section. */
+ char *section_name; /* Recorded section name. */
};

+#ifndef IMAGE_SCN_CNT_CODE
+# define IMAGE_SCN_CNT_CODE 0x20
+#endif
+#ifndef IMAGE_SCN_CNT_INITIALIZED_DATA
+# define IMAGE_SCN_CNT_INITIALIZED_DATA 0x40
+#endif
+#ifndef IMAGE_SCN_CNT_UNINITIALIZED_DATA
+# define IMAGE_SCN_CNT_UNINITIALIZED_DATA 0x80
+#endif
#define PE_SECTION_INDEX_TEXT 0
#define PE_SECTION_INDEX_DATA 1
#define PE_SECTION_INDEX_BSS 2
@@ -77,13 +98,40 @@ read_pe_section_index (const char *secti
}
}

+/* Get the index of the named section in our own full arrayi.
+ text, data and bss in that order. Return PE_SECTION_INDEX_INVALID
+ if passed an unrecognised section name. */
+
+static int
+get_pe_section_index (const char *section_name,
+ struct read_pe_section_data *sections,
+ int nb_sections)
+{
+ int i;
+ for (i = 0; i < nb_sections; i++)
+ if (strcmp (sections[i].section_name, section_name) == 0)
+ return i;
+ return PE_SECTION_INDEX_INVALID;
+}
+
+/* Structure used by get_section_vmas function below
+ to access section_data array and the size of the array
+ stored in nb_sections field. */
+struct pe_sections_info
+{
+ int nb_sections;
+ struct read_pe_section_data *sections;
+};
+
/* 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);
+ struct pe_sections_info *data = context;
+ struct read_pe_section_data *sections = data->sections;
+ int sectix = get_pe_section_index (sectp->name, sections,
+ data->nb_sections);

if (sectix != PE_SECTION_INDEX_INVALID)
{
@@ -95,58 +143,148 @@ get_section_vmas (bfd *abfd, asection *s
}
}
\f
-/* Create a minimal symbol entry for an exported symbol. */
+/* Create a minimal symbol entry for an exported symbol.
+ SYM_NAME contains the exported name or NULL if exported by ordinal,
+ FUNC_RVA contains the Relative Virtual Address of the symbol,
+ ORDINAL is the ordinal index value of the symbol,
+ SECTION_DATA contains information about the section in which the
+ symbol is declared,
+ DLL_NAME is the internal name of the DLL file,
+ OBJFILE is the objfile struct of DLL_NAME. */

static void
-add_pe_exported_sym (char *sym_name,
+add_pe_exported_sym (const char *sym_name,
unsigned long func_rva,
+ int ordinal,
const struct read_pe_section_data *section_data,
const char *dll_name, struct objfile *objfile)
{
+ char *qualified_name, *bare_name;
/* 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);
+ if (sym_name == NULL || *sym_name == '\0')
+ bare_name = xstrprintf ("#%d", ordinal);
+ else
+ bare_name = xstrdup (sym_name);

- strncpy (qualified_name, dll_name, dll_name_len);
- qualified_name[dll_name_len] = '!';
- strcpy (qualified_name + dll_name_len + 1, sym_name);
+ qualified_name = xstrprintf ("%s!%s", dll_name, bare_name);

- prim_record_minimal_symbol (qualified_name,
- vma, section_data->ms_type, objfile);
+ if ((section_data->ms_type == mst_unknown) && debug_coff_pe_read)
+ fprintf_unfiltered (gdb_stdlog , _("Unknown section type for \"%s\""
+ " for entry \"%s\" in dll \"%s\"\n"),
+ section_data->section_name, sym_name, dll_name);

+ prim_record_minimal_symbol (qualified_name, vma,
+ section_data->ms_type, objfile);
+
+ /* Enter the plain name as well, which might not be unique. */
+ prim_record_minimal_symbol (bare_name, vma, section_data->ms_type, objfile);
+ if (debug_coff_pe_read > 1)
+ fprintf_unfiltered (gdb_stdlog, _("Adding exported symbol \"%s\""
+ " in dll \"%s\"\n"), sym_name, dll_name);
xfree (qualified_name);
+ xfree (bare_name);
+}
+
+/* Create a minimal symbol entry for an exported forward symbol.
+ Return 1 if the forwarded function was found 0 otherwise.
+ SYM_NAME contains the exported name or NULL if exported by ordinal,
+ FORWARD_DLL_NAME is the name of the DLL in which the target symobl resides,
+ FORWARD_FUNC_NAME is the name of the target symbol in that DLL,
+ ORDINAL is the ordinal index value of the symbol,
+ DLL_NAME is the internal name of the DLL file,
+ OBJFILE is the objfile struct of DLL_NAME. */
+
+
+static int
+add_pe_forwarded_sym (const char *sym_name, const char *forward_dll_name,
+ const char *forward_func_name, int ordinal,
+ const char *dll_name, struct objfile *objfile)
+{
+ CORE_ADDR vma;
+ struct objfile *forward_objfile;
+ struct minimal_symbol *msymbol;
+ short section;
+ enum minimal_symbol_type msymtype;
+ int dll_name_len = strlen (dll_name);
+ char *qualified_name, *bare_name;
+ int forward_dll_name_len = strlen (forward_dll_name);
+ int forward_func_name_len = strlen (forward_func_name);
+ int forward_len = forward_dll_name_len + forward_func_name_len + 2;
+ char *forward_qualified_name = alloca (forward_len);
+
+ xsnprintf (forward_qualified_name, forward_len, "%s!%s", forward_dll_name,
+ forward_func_name);
+
+
+ msymbol = lookup_minimal_symbol_and_objfile (forward_qualified_name,
+ &forward_objfile);
+
+ if (!msymbol)
+ {
+ int i;
+
+ for (i = 0; i < forward_dll_name_len; i++)
+ forward_qualified_name[i] = tolower (forward_qualified_name[i]);
+ msymbol = lookup_minimal_symbol_and_objfile (forward_qualified_name,
+ &forward_objfile);
+ }
+
+ if (!msymbol)
+ {
+ if (debug_coff_pe_read)
+ fprintf_unfiltered (gdb_stdlog, _("Unable to find function \"%s\" in"
+ " dll \"%s\", forward of \"%s\" in dll \"%s\"\n"),
+ forward_func_name, forward_dll_name, sym_name,
+ dll_name);
+ return 0;
+ }
+
+ if (debug_coff_pe_read > 1)
+ fprintf_unfiltered (gdb_stdlog, _("Adding forwarded exported symbol"
+ " \"%s\" in dll \"%s\", pointing to \"%s\"\n"),
+ sym_name, dll_name, forward_qualified_name);
+
+ vma = SYMBOL_VALUE_ADDRESS (msymbol);
+ section = SYMBOL_SECTION (msymbol);
+ msymtype = MSYMBOL_TYPE (msymbol);
+
+ /* 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". */
+
+ if (sym_name == NULL || *sym_name == '\0')
+ bare_name = xstrprintf ("#%d", ordinal);
+ else
+ bare_name = xstrdup (sym_name);
+
+ qualified_name = xstrprintf ("%s!%s", dll_name, bare_name);
+
+ prim_record_minimal_symbol (qualified_name, vma, msymtype, objfile);

/* Enter the plain name as well, which might not be unique. */
- prim_record_minimal_symbol (sym_name, vma,
- section_data->ms_type, objfile);
+ prim_record_minimal_symbol (bare_name, vma, msymtype, objfile);
+ xfree (qualified_name);
+ xfree (bare_name);
+
+ return 1;
}

-/* Truncate a dll_name at the first dot character. */
+/* Truncate a dll_name at the last 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. */
- }
+ char * last_point = strrchr (dll_name, '.');

- else
- {
- ++dll_name;
- }
- }
+ if (last_point != NULL)
+ *last_point = '\0';
}
\f
/* Low-level support functions, direct from the ld module pe-dll.c. */
@@ -171,6 +309,14 @@ pe_get32 (bfd *abfd, int where)
}

static unsigned int
+pe_as16 (void *ptr)
+{
+ unsigned char *b = ptr;
+
+ return b[0] + (b[1] << 8);
+}
+
+static unsigned int
pe_as32 (void *ptr)
{
unsigned char *b = ptr;
@@ -186,35 +332,53 @@ void
read_pe_exported_syms (struct objfile *objfile)
{
bfd *dll = objfile->obfd;
+ unsigned long nbnormal, nbforward;
unsigned long pe_header_offset, opthdr_ofs, num_entries, i;
+ unsigned long export_opthdrrva, export_opthdrsize;
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;
+ char *dll_name = (char *) dll->filename;
+ int otherix = PE_SECTION_TABLE_SIZE;
+ int exportix = -1;
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
+ Initialization with RVA_START > RVA_END 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 read_pe_section_data *section_data;
+ struct pe_sections_info pe_sections_info;

- struct cleanup *back_to = 0;
+ struct cleanup *back_to = make_cleanup (null_cleanup, 0);

char const *target = bfd_get_target (objfile->obfd);

+ section_data = xzalloc (PE_SECTION_TABLE_SIZE
+ * sizeof (struct read_pe_section_data));
+
+ make_cleanup (free_current_contents, &section_data);
+
+ for (i=0; i < PE_SECTION_TABLE_SIZE; i++)
+ {
+ section_data[i].vma_offset = 0;
+ section_data[i].rva_start = 1;
+ section_data[i].rva_end = 0;
+ };
+ section_data[PE_SECTION_INDEX_TEXT].ms_type = mst_text;
+ section_data[PE_SECTION_INDEX_TEXT].section_name = ".text";
+ section_data[PE_SECTION_INDEX_DATA].ms_type = mst_data;
+ section_data[PE_SECTION_INDEX_DATA].section_name = ".data";
+ section_data[PE_SECTION_INDEX_BSS].ms_type = mst_bss;
+ section_data[PE_SECTION_INDEX_BSS].section_name = ".bss";
+
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
@@ -235,21 +399,21 @@ read_pe_exported_syms (struct objfile *o
{
return;
}
-
if (is_pe64)
{
- export_rva = pe_get32 (dll, opthdr_ofs + 112);
- export_size = pe_get32 (dll, opthdr_ofs + 116);
+ export_opthdrrva = pe_get32 (dll, opthdr_ofs + 112);
+ export_opthdrsize = pe_get32 (dll, opthdr_ofs + 116);
}
else
{
- export_rva = pe_get32 (dll, opthdr_ofs + 96);
- export_size = pe_get32 (dll, opthdr_ofs + 100);
+ export_opthdrrva = pe_get32 (dll, opthdr_ofs + 96);
+ export_opthdrsize = 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;
+ export_size = 0;

/* Get the rva and size of the export section. */
for (i = 0; i < nsections; i++)
@@ -261,17 +425,31 @@ read_pe_exported_syms (struct objfile *o
unsigned long fptr = pe_get32 (dll, secptr1 + 20);

bfd_seek (dll, (file_ptr) secptr1, SEEK_SET);
- bfd_bread (sname, (bfd_size_type) 8, dll);
+ bfd_bread (sname, (bfd_size_type) sizeof (sname), dll);

- if (vaddr <= export_rva && vaddr + vsize > export_rva)
+ if ((strcmp (sname, ".edata") == 0)
+ || (vaddr <= export_opthdrrva && export_opthdrrva < vaddr + vsize))
{
- expptr = fptr + (export_rva - vaddr);
- if (export_rva + export_size > vaddr + vsize)
- export_size = vsize - (export_rva - vaddr);
+ if (strcmp (sname, ".edata") != 0)
+ {
+ if (debug_coff_pe_read)
+ fprintf_unfiltered (gdb_stdlog, _("Export RVA for dll "
+ "\"%s\" is in section \"%s\"\n"),
+ dll_name, sname);
+ }
+ else if (export_opthdrrva != vaddr && debug_coff_pe_read)
+ fprintf_unfiltered (gdb_stdlog, _("Wrong value of export RVA"
+ " for dll \"%s\": 0x%lx instead of 0x%lx\n"),
+ dll_name, export_opthdrrva, vaddr);
+ expptr = fptr + (export_opthdrrva - vaddr);
+ exportix = i;
break;
}
}

+ export_rva = export_opthdrrva;
+ export_size = export_opthdrsize;
+
if (export_size == 0)
{
/* Empty export table. */
@@ -285,10 +463,11 @@ read_pe_exported_syms (struct objfile *o
unsigned long secptr1 = secptr + 40 * i;
unsigned long vsize = pe_get32 (dll, secptr1 + 8);
unsigned long vaddr = pe_get32 (dll, secptr1 + 12);
+ unsigned long characteristics = pe_get32 (dll, secptr1 + 36);
char sec_name[9];
int sectix;

- sec_name[8] = '\0';
+ memset (sec_name, 0, sizeof (sec_name));
bfd_seek (dll, (file_ptr) secptr1 + 0, SEEK_SET);
bfd_bread (sec_name, (bfd_size_type) 8, dll);

@@ -299,10 +478,32 @@ read_pe_exported_syms (struct objfile *o
section_data[sectix].rva_start = vaddr;
section_data[sectix].rva_end = vaddr + vsize;
}
+ else
+ {
+ char *name;
+
+ otherix++;
+ section_data = xrealloc (section_data, otherix
+ * sizeof (struct read_pe_section_data));
+ name = xstrdup (sec_name);
+ section_data[otherix - 1].section_name = name;
+ make_cleanup (xfree, name);
+ section_data[otherix - 1].rva_start = vaddr;
+ section_data[otherix - 1].rva_end = vaddr + vsize;
+ section_data[otherix - 1].vma_offset = 0;
+ if (characteristics & IMAGE_SCN_CNT_CODE)
+ section_data[otherix - 1].ms_type = mst_text;
+ else if (characteristics & IMAGE_SCN_CNT_INITIALIZED_DATA)
+ section_data[otherix - 1].ms_type = mst_data;
+ else if (characteristics & IMAGE_SCN_CNT_UNINITIALIZED_DATA)
+ section_data[otherix - 1].ms_type = mst_bss;
+ else
+ section_data[otherix - 1].ms_type = mst_unknown;
+ }
}

expdata = (unsigned char *) xmalloc (export_size);
- back_to = make_cleanup (xfree, expdata);
+ make_cleanup (xfree, expdata);

bfd_seek (dll, (file_ptr) expptr, SEEK_SET);
bfd_bread (expdata, (bfd_size_type) export_size, dll);
@@ -317,12 +518,15 @@ read_pe_exported_syms (struct objfile *o
/* 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);
+ pe_sections_info.nb_sections = otherix;
+ pe_sections_info.sections = section_data;
+
+ bfd_map_over_sections (dll, get_section_vmas, &pe_sections_info);

/* 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++)
+ for (i = 0; i < otherix; i++)
{
section_data[i].vma_offset
+= ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
@@ -332,31 +536,185 @@ read_pe_exported_syms (struct objfile *o
lower case for convenience on Windows. */
read_pe_truncate_name (dll_name);

+ if (debug_coff_pe_read)
+ fprintf_unfiltered (gdb_stdlog, _("DLL \"%s\" has %ld export entries,"
+ " base=%ld\n"), dll_name, nexp, ordbase);
+ nbforward = 0;
+ nbnormal = 0;
/* 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);
+ /* Retrieve ordinal value. */
+
+ unsigned long ordinal = pe_as16 (erva + ordinals + i * 2);
+

/* Pointer to the function address vector. */
- unsigned long func_rva = pe_as32 (erva + exp_funcbase + i * 4);
+ /* This is relatived to ordinal value. */
+ unsigned long func_rva = pe_as32 (erva + exp_funcbase +
+ ordinal * 4);

/* Find this symbol's section in our own array. */
int sectix = 0;
+ int section_found = 0;
+
+ /* First handle forward cases. */
+ if ((func_rva >= export_rva)
+ && (func_rva < export_rva + export_size))
+ {
+ char *forward_name = (char *) (erva + func_rva);
+ char *funcname = (char *) (erva + name_rva);
+ char *forward_dll_name = forward_name;
+ char *forward_func_name = forward_name;
+ char *sep = strrchr (forward_name, '.');
+
+ if (sep)
+ {
+ int len = (int) (sep - forward_name);

- for (sectix = 0; sectix < PE_SECTION_TABLE_SIZE; ++sectix)
+ forward_dll_name = alloca (len + 1);
+ strncpy (forward_dll_name, forward_name, len);
+ forward_dll_name[len] = '\0';
+ forward_func_name = ++sep;
+ }
+ if (add_pe_forwarded_sym (funcname, forward_dll_name,
+ forward_func_name, ordinal,
+ dll_name, objfile) != 0)
+ ++nbforward;
+ continue;
+ }
+
+ for (sectix = 0; sectix < otherix; ++sectix)
{
if ((func_rva >= section_data[sectix].rva_start)
&& (func_rva < section_data[sectix].rva_end))
{
+ section_found = 1;
add_pe_exported_sym (erva + name_rva,
- func_rva,
+ func_rva, ordinal,
section_data + sectix, dll_name, objfile);
+ ++nbnormal;
break;
}
}
+ if (!section_found)
+ {
+ char *funcname = (char *) (erva + name_rva);
+
+ if (name_rva == 0)
+ {
+ add_pe_exported_sym (NULL, func_rva, ordinal,
+ section_data, dll_name, objfile);
+ ++nbnormal;
+ }
+ else if (debug_coff_pe_read)
+ fprintf_unfiltered (gdb_stdlog, _("Export name \"%s\" ord. %lu,"
+ " RVA 0x%lx in dll \"%s\" not handled\n"),
+ funcname, ordinal, func_rva, dll_name);
+ }
}

- /* Discard expdata. */
+ if (debug_coff_pe_read)
+ fprintf_unfiltered (gdb_stdlog, _("Finished reading \"%s\", exports %ld,"
+ " forwards %ld, total %ld/%ld.\n"), dll_name, nbnormal,
+ nbforward, nbnormal + nbforward, nexp);
+ /* Discard expdata and section_data. */
do_cleanups (back_to);
}
+
+/* Extract from ABFD the offset of the .text section.
+ This offset is mainly related to the offset within the file.
+ The value was previously expected to be 0x1000 for all files,
+ but some Windows OS core DLLs seem to use 0x10000 section alignement
+ which modified the return value of that function.
+ Still return default 0x1000 value if ABFD is NULL or
+ if '.text' section is not found, but that should not happen... */
+
+#define DEFAULT_COFF_PE_TEXT_SECTION_OFFSET 0x1000
+
+CORE_ADDR
+pe_text_section_offset (struct bfd *abfd)
+
+{
+ 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;
+ char const *target;
+
+ if (!abfd)
+ return DEFAULT_COFF_PE_TEXT_SECTION_OFFSET;
+
+ target = bfd_get_target (abfd);
+
+ 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 DEFAULT_COFF_PE_TEXT_SECTION_OFFSET;
+ }
+
+ /* Get pe_header, optional header and numbers of sections. */
+ pe_header_offset = pe_get32 (abfd, 0x3c);
+ opthdr_ofs = pe_header_offset + 4 + 20;
+ nsections = pe_get16 (abfd, pe_header_offset + 4 + 2);
+ secptr = (pe_header_offset + 4 + 20 +
+ pe_get16 (abfd, pe_header_offset + 4 + 16));
+
+ /* 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 (abfd, secptr1 + 12);
+
+ bfd_seek (abfd, (file_ptr) secptr1, SEEK_SET);
+ bfd_bread (sname, (bfd_size_type) 8, abfd);
+ if (strcmp (sname, ".text") == 0)
+ return vaddr;
+ }
+
+ return DEFAULT_COFF_PE_TEXT_SECTION_OFFSET;
+}
+
+/* Implements "show debug coff_pe_read" command. */
+
+static void
+show_debug_coff_pe_read (struct ui_file *file, int from_tty,
+ struct cmd_list_element *c, const char *value)
+{
+ fprintf_filtered (file, _("Coff PE read debugging is %s.\n"), value);
+}
+
+/* Provide a prototype to silence -Wmissing-prototypes. */
+
+void _initialize_coff_pe_read (void);
+
+/* Adds "Set/show debug coff_pe_read" commands. */
+
+void
+_initialize_coff_pe_read (void)
+{
+ add_setshow_uinteger_cmd ("coff_pe_read", class_maintenance,
+ &debug_coff_pe_read,
+ _("Set coff PE read debugging."),
+ _("Show coff PE read debugging."),
+ _("When set, debugging messages for coff reading "
+ "of exported symbols are displayed."),
+ NULL, show_debug_coff_pe_read,
+ &setdebuglist, &showdebuglist);
+}
Index: windows-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/windows-tdep.c,v
retrieving revision 1.17
diff -u -p -r1.17 windows-tdep.c
--- windows-tdep.c 9 Nov 2012 19:58:02 -0000 1.17
+++ windows-tdep.c 27 Nov 2012 14:45:02 -0000
@@ -27,6 +27,10 @@
#include "gdbcmd.h"
#include "gdbthread.h"
#include "objfiles.h"
+#include "symfile.h"
+#include "coff-pe-read.h"
+#include "gdb_bfd.h"
+#include "complaints.h"

struct cmd_list_element *info_w32_cmdlist;

@@ -387,15 +391,21 @@ windows_xfer_shared_library (const char*
struct gdbarch *gdbarch, struct obstack *obstack)
{
char *p;
+ struct bfd * dll;
+ CORE_ADDR text_offset;
+
obstack_grow_str (obstack, "<library name=\"");
p = xml_escape_text (so_name);
obstack_grow_str (obstack, p);
xfree (p);
obstack_grow_str (obstack, "\"><segment address=\"");
- /* The symbols in a dll are offset by 0x1000, which is the
- offset from 0 of the first byte in an image - because of the file
- header and the section alignment. */
- obstack_grow_str (obstack, paddress (gdbarch, load_addr + 0x1000));
+ dll = gdb_bfd_open_maybe_remote (so_name);
+ /* The following calls are OK even if dll is NULL.
+ The default value 0x1000 is returned by pe_text_section_offset
+ in that case. */
+ text_offset = pe_text_section_offset (dll);
+ gdb_bfd_unref (dll);
+ obstack_grow_str (obstack, paddress (gdbarch, load_addr + text_offset));
obstack_grow_str (obstack, "\"/></library>");
}