* coff-pe-read.c: New file - support reading of minimal symbols from a portable

executable using the export table.
* coff-pe-read.h: New file.
* coffread.c: Include coff-pe-read.h.
(coff_symtab_read): Call read_pe_exported_syms iff no recognized debugging
symbols found.
* Makefile.in (SFILES): Add coff-pe-read.o.
(coff_pe_read_h): Define.
(COMMON_OBS): Add coff-pe-read.o.
(coffread.o): Add coff_pe_read_h dependency.
(coff-pe-read.o): New target.

1 files changed, 346 insertions, 0 deletions

diff --git a/gdb/coff-pe-read.c b/gdb/coff-pe-read.c
new file mode 100644
index 0000000..2d1e854
--- /dev/null
+++ b/gdb/coff-pe-read.c
@@ -0,0 +1,346 @@
+/* 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 2003 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 2 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, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.
+
+   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);
+  int count;
+
+  /* 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;
+
+  /* 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);
+
+  if ((strcmp (target, "pe-i386") != 0) && (strcmp (target, "pei-i386") != 0))
+    {
+      /* This is not an i386 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;
+  num_entries = pe_get32 (dll, opthdr_ofs + 92);
+
+  if (num_entries < 1)		/* No exports.  */
+    {
+      return;
+    }
+
+  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);
+      unsigned long flags = pe_get32 (dll, secptr1 + 36);
+      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));
+    }
+
+  printf_filtered ("Minimal symbols from %s...", dll_name);
+  wrap_here ("");
+
+  /* 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);
+}