2009-12-11 Tristan Gingold <gingold@adacore.com>

	* symfile.h (find_separate_debug_file_by_buildid): Remove prototype.
	(bfd_open_maybe_remote): New prototype.
	* symfile.c (bfd_open_maybe_remote): New function.
	(separate_debug_file_exists, reread_symbols): Use it.
	(struct build_id, build_id_bfd_get, build_id_verify)
	(build_id_to_debug_filename)
	(find_separate_debug_file_by_buildid): Move these ...
	* elfread.c (struct build_id)
	(build_id_bfd_get, build_id_verify, build_id_to_debug_filename)
	(find_separate_debug_file_by_buildid): ... here.

1 files changed, 151 insertions, 0 deletions

diff --git a/gdb/elfread.c b/gdb/elfread.c
index a47e687fb6..5e4e473b7a 100644
--- a/gdb/elfread.c
+++ b/gdb/elfread.c
@@ -568,6 +568,157 @@ elf_symtab_read (struct objfile *objfile, int type,
     }
 }
 
+struct build_id
+  {
+    size_t size;
+    gdb_byte data[1];
+  };
+
+/* Locate NT_GNU_BUILD_ID from ABFD and return its content.  */
+
+static struct build_id *
+build_id_bfd_get (bfd *abfd)
+{
+  struct build_id *retval;
+
+  if (!bfd_check_format (abfd, bfd_object)
+      || bfd_get_flavour (abfd) != bfd_target_elf_flavour
+      || elf_tdata (abfd)->build_id == NULL)
+    return NULL;
+
+  retval = xmalloc (sizeof *retval - 1 + elf_tdata (abfd)->build_id_size);
+  retval->size = elf_tdata (abfd)->build_id_size;
+  memcpy (retval->data, elf_tdata (abfd)->build_id, retval->size);
+
+  return retval;
+}
+
+/* Return if FILENAME has NT_GNU_BUILD_ID matching the CHECK value.  */
+
+static int
+build_id_verify (const char *filename, struct build_id *check)
+{
+  bfd *abfd;
+  struct build_id *found = NULL;
+  int retval = 0;
+
+  /* We expect to be silent on the non-existing files.  */
+  abfd = bfd_open_maybe_remote (filename);
+  if (abfd == NULL)
+    return 0;
+
+  found = build_id_bfd_get (abfd);
+
+  if (found == NULL)
+    warning (_("File \"%s\" has no build-id, file skipped"), filename);
+  else if (found->size != check->size
+           || memcmp (found->data, check->data, found->size) != 0)
+    warning (_("File \"%s\" has a different build-id, file skipped"), filename);
+  else
+    retval = 1;
+
+  if (!bfd_close (abfd))
+    warning (_("cannot close \"%s\": %s"), filename,
+	     bfd_errmsg (bfd_get_error ()));
+
+  xfree (found);
+
+  return retval;
+}
+
+static char *
+build_id_to_debug_filename (struct build_id *build_id)
+{
+  char *link, *debugdir, *retval = NULL;
+
+  /* DEBUG_FILE_DIRECTORY/.build-id/ab/cdef */
+  link = alloca (strlen (debug_file_directory) + (sizeof "/.build-id/" - 1) + 1
+		 + 2 * build_id->size + (sizeof ".debug" - 1) + 1);
+
+  /* Keep backward compatibility so that DEBUG_FILE_DIRECTORY being "" will
+     cause "/.build-id/..." lookups.  */
+
+  debugdir = debug_file_directory;
+  do
+    {
+      char *s, *debugdir_end;
+      gdb_byte *data = build_id->data;
+      size_t size = build_id->size;
+
+      while (*debugdir == DIRNAME_SEPARATOR)
+	debugdir++;
+
+      debugdir_end = strchr (debugdir, DIRNAME_SEPARATOR);
+      if (debugdir_end == NULL)
+	debugdir_end = &debugdir[strlen (debugdir)];
+
+      memcpy (link, debugdir, debugdir_end - debugdir);
+      s = &link[debugdir_end - debugdir];
+      s += sprintf (s, "/.build-id/");
+      if (size > 0)
+	{
+	  size--;
+	  s += sprintf (s, "%02x", (unsigned) *data++);
+	}
+      if (size > 0)
+	*s++ = '/';
+      while (size-- > 0)
+	s += sprintf (s, "%02x", (unsigned) *data++);
+      strcpy (s, ".debug");
+
+      /* lrealpath() is expensive even for the usually non-existent files.  */
+      if (access (link, F_OK) == 0)
+	retval = lrealpath (link);
+
+      if (retval != NULL && !build_id_verify (retval, build_id))
+	{
+	  xfree (retval);
+	  retval = NULL;
+	}
+
+      if (retval != NULL)
+	break;
+
+      debugdir = debugdir_end;
+    }
+  while (*debugdir != 0);
+
+  return retval;
+}
+
+static char *
+find_separate_debug_file_by_buildid (struct objfile *objfile)
+{
+  asection *sect;
+  char *basename, *name_copy, *debugdir;
+  char *dir = NULL;
+  char *debugfile = NULL;
+  char *canon_name = NULL;
+  bfd_size_type debuglink_size;
+  unsigned long crc32;
+  int i;
+  struct build_id *build_id;
+
+  build_id = build_id_bfd_get (objfile->obfd);
+  if (build_id != NULL)
+    {
+      char *build_id_name;
+
+      build_id_name = build_id_to_debug_filename (build_id);
+      xfree (build_id);
+      /* Prevent looping on a stripped .debug file.  */
+      if (build_id_name != NULL && strcmp (build_id_name, objfile->name) == 0)
+        {
+	  warning (_("\"%s\": separate debug info file has no debug info"),
+		   build_id_name);
+	  xfree (build_id_name);
+	}
+      else if (build_id_name != NULL)
+        return build_id_name;
+    }
+  return NULL;
+}
+
 /* Scan and build partial symbols for a symbol file.
    We have been initialized by a call to elf_symfile_init, which 
    currently does nothing.