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PATCH: Re: readelf -D --reloc bug

H. J. Lu hjl@lucon.org
Mon Mar 31 17:45:00 GMT 2003 
On Mon, Mar 31, 2003 at 08:32:56AM -0800, H. J. Lu wrote:
> On Mon, Mar 31, 2003 at 08:11:51AM -0800, H. J. Lu wrote:
> > # readelf -D --reloc /bin/ls
> > 
> > There are no dynamic relocations in this file.
> > 
> > It is clearly not true.
> > 
> 
> There are several problems with -D:
> 
> 1. Not all elements in dynamic_info are filled, including those for
> relocation information.
> 2. Readelf assumes there can only be DT_REL, DT_RELA or DT_JMPREL, but
> not at the same time.
> 
> H.J.

Here is a patch.


H.J.
----
2003-03-31  H.J. Lu <hjl@gnu.org>

	* readelf.c (dynamic_relocations): New.
	(process_relocs) Properly handle dynamic relocation.
	(process_dynamic_segment): Fill relocation elements in
	dynamic_info.

--- binutils/readelf.c.dyn	2003-03-28 17:05:04.000000000 -0800
+++ binutils/readelf.c	2003-03-31 08:57:42.000000000 -0800
@@ -3798,6 +3798,21 @@ process_section_headers (file)
   return 1;
 }
 
+#define NUM_DYNAMIC_RELOCATIONS	3
+
+struct
+{
+  const char *name;
+  int reloc;
+  int size;
+  int rela;
+} dynamic_relocations [NUM_DYNAMIC_RELOCATIONS] =
+{
+    { "REL", DT_REL, DT_RELSZ, FALSE },
+    { "RELA", DT_RELA, DT_RELASZ, TRUE },
+    { "PLT", DT_JMPREL, DT_PLTRELSZ, UNKNOWN }
+};
+
 /* Process the reloc section.  */
 static int
 process_relocs (file)
@@ -3812,53 +3827,49 @@ process_relocs (file)
 
   if (do_using_dynamic)
     {
-      int is_rela = FALSE;
-
-      rel_size   = 0;
-      rel_offset = 0;
+      int is_rela;
+      const char *name;
+      int has_dynamic_reloc;
+      int i;
+      
+      has_dynamic_reloc = 0;
+
+      for (i = 0; i < NUM_DYNAMIC_RELOCATIONS; i++)
+	{
+	  is_rela = dynamic_relocations [i].rela;
+	  name = dynamic_relocations [i].name;
+	  rel_size = dynamic_info [dynamic_relocations [i].size];
+	  rel_offset = dynamic_info [dynamic_relocations [i].reloc];
 
-      if (dynamic_info[DT_REL])
-	{
-	  rel_offset = dynamic_info[DT_REL];
-	  rel_size   = dynamic_info[DT_RELSZ];
-	  is_rela    = FALSE;
-	}
-      else if (dynamic_info[DT_RELA])
-	{
-	  rel_offset = dynamic_info[DT_RELA];
-	  rel_size   = dynamic_info[DT_RELASZ];
-	  is_rela    = TRUE;
-	}
-      else if (dynamic_info[DT_JMPREL])
-	{
-	  rel_offset = dynamic_info[DT_JMPREL];
-	  rel_size   = dynamic_info[DT_PLTRELSZ];
+	  has_dynamic_reloc |= rel_size;
 
-	  switch (dynamic_info[DT_PLTREL])
+	  if (is_rela == UNKNOWN)
 	    {
-	    case DT_REL:
-	      is_rela = FALSE;
-	      break;
-	    case DT_RELA:
-	      is_rela = TRUE;
-	      break;
-	    default:
-	      is_rela = UNKNOWN;
-	      break;
+	      if (dynamic_relocations [i].reloc == DT_JMPREL)
+		switch (dynamic_info[DT_PLTREL])
+		  {
+		  case DT_REL:
+		    is_rela = FALSE;
+		    break;
+		  case DT_RELA:
+		    is_rela = TRUE;
+		    break;
+		  }
 	    }
-	}
 
-      if (rel_size)
-	{
-	  printf
-	    (_("\nRelocation section at offset 0x%lx contains %ld bytes:\n"),
-	     rel_offset, rel_size);
+	  if (rel_size)
+	    {
+	      printf
+		(_("\n'%s' relocation section at offset 0x%lx contains %ld bytes:\n"),
+		 name, rel_offset, rel_size);
 
-	  dump_relocations (file, rel_offset - loadaddr, rel_size,
-			    dynamic_symbols, num_dynamic_syms, dynamic_strings,
-			    is_rela);
+	      dump_relocations (file, rel_offset - loadaddr, rel_size,
+				dynamic_symbols, num_dynamic_syms,
+				dynamic_strings, is_rela);
+	    }
 	}
-      else
+
+      if (! has_dynamic_reloc)
 	printf (_("\nThere are no dynamic relocations in this file.\n"));
     }
   else
@@ -5001,6 +5012,7 @@ process_dynamic_segment (file)
 	  break;
 
 	case DT_PLTREL:
+	  dynamic_info[entry->d_tag] = entry->d_un.d_val;
 	  if (do_dynamic)
 	    puts (get_dynamic_type (entry->d_un.d_val));
 	  break;
@@ -5075,6 +5087,7 @@ process_dynamic_segment (file)
 	case DT_RELAENT	:
 	case DT_SYMENT	:
 	case DT_RELENT	:
+	  dynamic_info[entry->d_tag] = entry->d_un.d_val;
 	case DT_PLTPADSZ:
 	case DT_MOVEENT	:
 	case DT_MOVESZ	:
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