Automatic date update in version.in

[deliverable/binutils-gdb.git] / bfd / format.c

diff --git a/bfd/format.c b/bfd/format.c
index 4d89a85e0aa4028419ed131dd3e998b06af889d7..ab98486fb4526919ffbaeddc3d1c76d331ff3606 100644 (file)
--- a/bfd/format.c
+++ b/bfd/format.c
@@ -1,6 +1,5 @@
 /* Generic BFD support for file formats.
 /* Generic BFD support for file formats.

-   Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1999, 2000, 2001, 2002,
-   2003, 2005, 2007, 2008, 2009 Free Software Foundation, Inc.
+   Copyright (C) 1990-2020 Free Software Foundation, Inc.

    Written by Cygnus Support.
 
    This file is part of BFD, the Binary File Descriptor library.
    Written by Cygnus Support.
 
    This file is part of BFD, the Binary File Descriptor library.


@@ -95,6 +94,113 @@ bfd_check_format (bfd *abfd, bfd_format format)
   return bfd_check_format_matches (abfd, format, NULL);
 }
 
   return bfd_check_format_matches (abfd, format, NULL);
 }
 

+struct bfd_preserve
+{
+  void *marker;
+  void *tdata;
+  flagword flags;
+  const struct bfd_arch_info *arch_info;
+  struct bfd_section *sections;
+  struct bfd_section *section_last;
+  unsigned int section_count;
+  unsigned int section_id;
+  struct bfd_hash_table section_htab;
+  const struct bfd_build_id *build_id;
+  bfd_cleanup cleanup;
+};
+
+/* When testing an object for compatibility with a particular target
+   back-end, the back-end object_p function needs to set up certain
+   fields in the bfd on successfully recognizing the object.  This
+   typically happens in a piecemeal fashion, with failures possible at
+   many points.  On failure, the bfd is supposed to be restored to its
+   initial state, which is virtually impossible.  However, restoring a
+   subset of the bfd state works in practice.  This function stores
+   the subset.  */
+
+static bfd_boolean
+bfd_preserve_save (bfd *abfd, struct bfd_preserve *preserve,
+                  bfd_cleanup cleanup)
+{
+  preserve->tdata = abfd->tdata.any;
+  preserve->arch_info = abfd->arch_info;
+  preserve->flags = abfd->flags;
+  preserve->sections = abfd->sections;
+  preserve->section_last = abfd->section_last;
+  preserve->section_count = abfd->section_count;
+  preserve->section_id = _bfd_section_id;
+  preserve->section_htab = abfd->section_htab;
+  preserve->marker = bfd_alloc (abfd, 1);
+  preserve->build_id = abfd->build_id;
+  preserve->cleanup = cleanup;
+  if (preserve->marker == NULL)
+    return FALSE;
+
+  return bfd_hash_table_init (&abfd->section_htab, bfd_section_hash_newfunc,
+                             sizeof (struct section_hash_entry));
+}
+
+/* Clear out a subset of BFD state.  */
+
+static void
+bfd_reinit (bfd *abfd, unsigned int section_id, bfd_cleanup cleanup)
+{
+  _bfd_section_id = section_id;
+  if (cleanup)
+    cleanup (abfd);
+  abfd->tdata.any = NULL;
+  abfd->arch_info = &bfd_default_arch_struct;
+  abfd->flags &= BFD_FLAGS_SAVED;
+  bfd_section_list_clear (abfd);
+}
+
+/* Restores bfd state saved by bfd_preserve_save.  */
+
+static bfd_cleanup
+bfd_preserve_restore (bfd *abfd, struct bfd_preserve *preserve)
+{
+  bfd_hash_table_free (&abfd->section_htab);
+
+  abfd->tdata.any = preserve->tdata;
+  abfd->arch_info = preserve->arch_info;
+  abfd->flags = preserve->flags;
+  abfd->section_htab = preserve->section_htab;
+  abfd->sections = preserve->sections;
+  abfd->section_last = preserve->section_last;
+  abfd->section_count = preserve->section_count;
+  _bfd_section_id = preserve->section_id;
+  abfd->build_id = preserve->build_id;
+
+  /* bfd_release frees all memory more recently bfd_alloc'd than
+     its arg, as well as its arg.  */
+  bfd_release (abfd, preserve->marker);
+  preserve->marker = NULL;
+  return preserve->cleanup;
+}
+
+/* Called when the bfd state saved by bfd_preserve_save is no longer
+   needed.  */
+
+static void
+bfd_preserve_finish (bfd *abfd ATTRIBUTE_UNUSED, struct bfd_preserve *preserve)
+{
+  if (preserve->cleanup)
+    {
+      /* Run the cleanup, assuming that all it will need is the
+        tdata at the time the cleanup was returned.  */
+      void *tdata = abfd->tdata.any;
+      abfd->tdata.any = preserve->tdata;
+      preserve->cleanup (abfd);
+      abfd->tdata.any = tdata;
+    }
+  /* It would be nice to be able to free more memory here, eg. old
+     tdata, but that's not possible since these blocks are sitting
+     inside bfd_alloc'd memory.  The section hash is on a separate
+     objalloc.  */
+  bfd_hash_table_free (&preserve->section_htab);
+  preserve->marker = NULL;
+}
+

 /*
 FUNCTION
        bfd_check_format_matches
 /*
 FUNCTION
        bfd_check_format_matches


@@ -119,11 +225,17 @@ bfd_boolean
 bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
 {
   extern const bfd_target binary_vec;
 bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
 {
   extern const bfd_target binary_vec;

+#if BFD_SUPPORTS_PLUGINS
+  extern const bfd_target plugin_vec;
+#endif

   const bfd_target * const *target;
   const bfd_target **matching_vector = NULL;
   const bfd_target * const *target;
   const bfd_target **matching_vector = NULL;

-  const bfd_target *save_targ, *right_targ, *ar_right_targ;
-  int match_count;
+  const bfd_target *save_targ, *right_targ, *ar_right_targ, *match_targ;
+  int match_count, best_count, best_match;

   int ar_match_index;
   int ar_match_index;

+  unsigned int initial_section_id = _bfd_section_id;
+  struct bfd_preserve preserve, preserve_match;
+  bfd_cleanup cleanup = NULL;

 
   if (matching != NULL)
     *matching = NULL;
 
   if (matching != NULL)
     *matching = NULL;


@@ -138,15 +250,9 @@ bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
   if (abfd->format != bfd_unknown)
     return abfd->format == format;
 
   if (abfd->format != bfd_unknown)
     return abfd->format == format;
 

-  /* Since the target type was defaulted, check them
-     all in the hope that one will be uniquely recognized.  */
-  save_targ = abfd->xvec;
-  match_count = 0;
-  ar_match_index = _bfd_target_vector_entries;
-

   if (matching != NULL || *bfd_associated_vector != NULL)
     {
   if (matching != NULL || *bfd_associated_vector != NULL)
     {

-      bfd_size_type amt;
+      size_t amt;

 
       amt = sizeof (*matching_vector) * 2 * _bfd_target_vector_entries;
       matching_vector = (const bfd_target **) bfd_malloc (amt);
 
       amt = sizeof (*matching_vector) * 2 * _bfd_target_vector_entries;
       matching_vector = (const bfd_target **) bfd_malloc (amt);


@@ -154,11 +260,13 @@ bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
        return FALSE;
     }
 
        return FALSE;
     }
 

-  right_targ = 0;
-  ar_right_targ = 0;
-

   /* Presume the answer is yes.  */
   abfd->format = format;
   /* Presume the answer is yes.  */
   abfd->format = format;

+  save_targ = abfd->xvec;
+
+  preserve_match.marker = NULL;
+  if (!bfd_preserve_save (abfd, &preserve, NULL))
+    goto err_ret;

 
   /* If the target type was explicitly specified, just check that target.  */
   if (!abfd->target_defaulted)
 
   /* If the target type was explicitly specified, just check that target.  */
   if (!abfd->target_defaulted)


@@ -166,9 +274,9 @@ bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
       if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0)        /* rewind! */
        goto err_ret;
 
       if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0)        /* rewind! */
        goto err_ret;
 

-      right_targ = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));
+      cleanup = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));

 
 

-      if (right_targ)
+      if (cleanup)

        goto ok_ret;
 
       /* For a long time the code has dropped through to check all
        goto ok_ret;
 
       /* For a long time the code has dropped through to check all


@@ -187,64 +295,115 @@ bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
        goto err_unrecog;
     }
 
        goto err_unrecog;
     }
 

+  /* Since the target type was defaulted, check them all in the hope
+     that one will be uniquely recognized.  */
+  right_targ = NULL;
+  ar_right_targ = NULL;
+  match_targ = NULL;
+  best_match = 256;
+  best_count = 0;
+  match_count = 0;
+  ar_match_index = _bfd_target_vector_entries;
+

   for (target = bfd_target_vector; *target != NULL; target++)
     {
   for (target = bfd_target_vector; *target != NULL; target++)
     {

-      const bfd_target *temp;
-      bfd_error_type err;
+      void **high_water;

 
 

-      /* Don't check the default target twice.  */
+      /* The binary target matches anything, so don't return it when
+        searching.  Don't match the plugin target if we have another
+        alternative since we want to properly set the input format
+        before allowing a plugin to claim the file.  Also, don't
+        check the default target twice.  */

       if (*target == &binary_vec
       if (*target == &binary_vec

+#if BFD_SUPPORTS_PLUGINS
+         || (match_count != 0 && *target == &plugin_vec)
+#endif

          || (!abfd->target_defaulted && *target == save_targ))
        continue;
 
          || (!abfd->target_defaulted && *target == save_targ))
        continue;
 

-      abfd->xvec = *target;    /* Change BFD's target temporarily.  */
+      /* If we already tried a match, the bfd is modified and may
+        have sections attached, which will confuse the next
+        _bfd_check_format call.  */
+      bfd_reinit (abfd, initial_section_id, cleanup);
+      /* Free bfd_alloc memory too.  If we have matched and preserved
+        a target then the high water mark is that much higher.  */
+      if (preserve_match.marker)
+       high_water = &preserve_match.marker;
+      else
+       high_water = &preserve.marker;
+      bfd_release (abfd, *high_water);
+      *high_water = bfd_alloc (abfd, 1);
+
+      /* Change BFD's target temporarily.  */
+      abfd->xvec = *target;

 
       if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0)
        goto err_ret;
 
 
       if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0)
        goto err_ret;
 

-      /* If _bfd_check_format neglects to set bfd_error, assume
-        bfd_error_wrong_format.  We didn't used to even pay any
-        attention to bfd_error, so I suspect that some
-        _bfd_check_format might have this problem.  */
-      bfd_set_error (bfd_error_wrong_format);
-
-      temp = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));
-
-      if (temp && (abfd->format != bfd_archive || bfd_has_map (abfd)))
+      cleanup = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));
+      if (cleanup)

        {
        {

-         /* This format checks out as ok!  */
-         right_targ = temp;
-
-         /* If this is the default target, accept it, even if other
-            targets might match.  People who want those other targets
-            have to set the GNUTARGET variable.  */
-         if (temp == bfd_default_vector[0])
+         int match_priority = abfd->xvec->match_priority;
+#if BFD_SUPPORTS_PLUGINS
+         /* If this object can be handled by a plugin, give that the
+            lowest priority; objects both handled by a plugin and
+            with an underlying object format will be claimed
+            separately by the plugin.  */
+         if (*target == &plugin_vec)
+           match_priority = (*target)->match_priority;
+#endif
+
+         if (abfd->format != bfd_archive
+             || (bfd_has_map (abfd)
+                 && bfd_get_error () != bfd_error_wrong_object_format))

            {
            {

-             match_count = 1;
-             break;
+             /* If this is the default target, accept it, even if
+                other targets might match.  People who want those
+                other targets have to set the GNUTARGET variable.  */
+             if (abfd->xvec == bfd_default_vector[0])
+               goto ok_ret;
+
+             if (matching_vector)
+               matching_vector[match_count] = abfd->xvec;
+             match_count++;
+
+             if (match_priority < best_match)
+               {
+                 best_match = match_priority;
+                 best_count = 0;
+               }
+             if (match_priority <= best_match)
+               {
+                 /* This format checks out as ok!  */
+                 right_targ = abfd->xvec;
+                 best_count++;
+               }
+           }
+         else
+           {
+             /* An archive with no armap or objects of the wrong
+                type.  We want this target to match if we get no
+                better matches.  */
+             if (ar_right_targ != bfd_default_vector[0])
+               ar_right_targ = *target;
+             if (matching_vector)
+               matching_vector[ar_match_index] = *target;
+             ar_match_index++;

            }
 
            }
 

-         if (matching_vector)
-           matching_vector[match_count] = temp;
-         match_count++;
-       }
-      else if (temp
-              || (err = bfd_get_error ()) == bfd_error_wrong_object_format
-              || err == bfd_error_file_ambiguously_recognized)
-       {
-         /* An archive with no armap or objects of the wrong type,
-            or an ambiguous match.  We want this target to match
-            if we get no better matches.  */
-         if (ar_right_targ != bfd_default_vector[0])
-           ar_right_targ = *target;
-         if (matching_vector)
-           matching_vector[ar_match_index] = *target;
-         ar_match_index++;
+         if (preserve_match.marker == NULL)
+           {
+             match_targ = abfd->xvec;
+             if (!bfd_preserve_save (abfd, &preserve_match, cleanup))
+               goto err_ret;
+             cleanup = NULL;
+           }

        }
        }

-      else if (err != bfd_error_wrong_format)
-       goto err_ret;

     }
 
     }
 

+  if (best_count == 1)
+    match_count = 1;
+

   if (match_count == 0)
     {
       /* Try partial matches.  */
   if (match_count == 0)
     {
       /* Try partial matches.  */


@@ -265,6 +424,9 @@ bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
        }
     }
 
        }
     }
 

+  /* We have more than one equally good match.  If any of the best
+     matches is a target in config.bfd targ_defvec or targ_selvecs,
+     choose it.  */

   if (match_count > 1)
     {
       const bfd_target * const *assoc = bfd_associated_vector;
   if (match_count > 1)
     {
       const bfd_target * const *assoc = bfd_associated_vector;


@@ -274,7 +436,8 @@ bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
          int i = match_count;
 
          while (--i >= 0)
          int i = match_count;
 
          while (--i >= 0)

-           if (matching_vector[i] == right_targ)
+           if (matching_vector[i] == right_targ
+               && right_targ->match_priority <= best_match)

              break;
 
          if (i >= 0)
              break;
 
          if (i >= 0)


@@ -285,11 +448,50 @@ bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
        }
     }
 
        }
     }
 

+  /* We still have more than one equally good match, and at least some
+     of the targets support match priority.  Choose the first of the
+     best matches.  */
+  if (matching_vector && match_count > 1 && best_count != match_count)
+    {
+      int i;
+
+      for (i = 0; i < match_count; i++)
+       {
+         right_targ = matching_vector[i];
+         if (right_targ->match_priority <= best_match)
+           break;
+       }
+      match_count = 1;
+    }
+
+  /* There is way too much undoing of half-known state here.  We
+     really shouldn't iterate on live bfd's.  Note that saving the
+     whole bfd and restoring it would be even worse; the first thing
+     you notice is that the cached bfd file position gets out of sync.  */
+  if (preserve_match.marker != NULL)
+    cleanup = bfd_preserve_restore (abfd, &preserve_match);
+

   if (match_count == 1)
     {
   if (match_count == 1)
     {

-    ok_ret:
-      abfd->xvec = right_targ;         /* Change BFD's target permanently.  */
+      abfd->xvec = right_targ;
+      /* If we come out of the loop knowing that the last target that
+        matched is the one we want, then ABFD should still be in a usable
+        state (except possibly for XVEC).  This is not just an
+        optimisation.  In the case of plugins a match against the
+        plugin target can result in the bfd being changed such that
+        it no longer matches the plugin target, nor will it match
+        RIGHT_TARG again.  */
+      if (match_targ != right_targ)
+       {
+         bfd_reinit (abfd, initial_section_id, cleanup);
+         bfd_release (abfd, preserve.marker);
+         if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0)
+           goto err_ret;
+         cleanup = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));
+         BFD_ASSERT (cleanup != NULL);
+       }

 
 

+    ok_ret:

       /* If the file was opened for update, then `output_has_begun'
         some time ago when the file was created.  Do not recompute
         sections sizes or alignments in _bfd_set_section_contents.
       /* If the file was opened for update, then `output_has_begun'
         some time ago when the file was created.  Do not recompute
         sections sizes or alignments in _bfd_set_section_contents.


@@ -300,7 +502,12 @@ bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
 
       if (matching_vector)
        free (matching_vector);
 
       if (matching_vector)
        free (matching_vector);

-      return TRUE;                     /* File position has moved, BTW.  */
+      if (preserve_match.marker != NULL)
+       bfd_preserve_finish (abfd, &preserve_match);
+      bfd_preserve_finish (abfd, &preserve);
+
+      /* File position has moved, BTW.  */
+      return TRUE;

     }
 
   if (match_count == 0)
     }
 
   if (match_count == 0)


@@ -308,15 +515,21 @@ bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
     err_unrecog:
       bfd_set_error (bfd_error_file_not_recognized);
     err_ret:
     err_unrecog:
       bfd_set_error (bfd_error_file_not_recognized);
     err_ret:

+      if (cleanup)
+       cleanup (abfd);

       abfd->xvec = save_targ;
       abfd->format = bfd_unknown;
       if (matching_vector)
        free (matching_vector);
       abfd->xvec = save_targ;
       abfd->format = bfd_unknown;
       if (matching_vector)
        free (matching_vector);

+      if (preserve_match.marker != NULL)
+       bfd_preserve_finish (abfd, &preserve_match);
+      bfd_preserve_restore (abfd, &preserve);

       return FALSE;
     }
 
       return FALSE;
     }
 

-  abfd->xvec = save_targ;              /* Restore original target type.  */
-  abfd->format = bfd_unknown;          /* Restore original format.  */
+  /* Restore original target type and format.  */
+  abfd->xvec = save_targ;
+  abfd->format = bfd_unknown;

   bfd_set_error (bfd_error_file_ambiguously_recognized);
 
   if (matching)
   bfd_set_error (bfd_error_file_ambiguously_recognized);
 
   if (matching)


@@ -331,6 +544,13 @@ bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
          *(const char **) &matching_vector[match_count] = name;
        }
     }
          *(const char **) &matching_vector[match_count] = name;
        }
     }

+  else if (matching_vector)
+    free (matching_vector);
+  if (cleanup)
+    cleanup (abfd);
+  if (preserve_match.marker != NULL)
+    bfd_preserve_finish (abfd, &preserve_match);
+  bfd_preserve_restore (abfd, &preserve);

   return FALSE;
 }
 
   return FALSE;
 }