malloc: Remove LD_TRACE_PRELINKING usage from mtrace

The fix for BZ#22716 replacde LD_TRACE_LOADED_OBJECTS with
LD_TRACE_PRELINKING so mtrace could record executable address
position.

To provide the same information, LD_TRACE_LOADED_OBJECTS is
extended where a value or '2' also prints the executable address
as well.  It avoid adding another loader environment variable
to be used solely for mtrace.  The vDSO will be printed as
a default library (with '=>' pointing the same name), which is
ok since both mtrace and ldd already handles it.

The mtrace script is changed to also parse the new format.  To
correctly support PIE and non-PIE executables, both the default
mtrace address and the one calculated as used (it fixes mtrace
for non-PIE exectuable as for BZ#22716 for PIE).

Checked on x86_64-linux-gnu.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

1 files changed, 13 insertions, 9 deletions

diff --git a/elf/rtld.c b/elf/rtld.c
index 5f089038e1..aa18256d86 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -2104,18 +2104,18 @@ dl_main (const ElfW(Phdr) *phdr,
 	_dl_printf ("\tstatically linked\n");
       else
 	{
-	  for (l = main_map->l_next; l; l = l->l_next)
+	  for (l = state.mode_trace_program ? main_map : main_map->l_next;
+	       l; l = l->l_next) {
 	    if (l->l_faked)
 	      /* The library was not found.  */
-	      _dl_printf ("\t%s => not found\n", l->l_libname->name);
-	    else if (strcmp (l->l_libname->name, l->l_name) == 0)
-	      _dl_printf ("\t%s (0x%0*Zx)\n", l->l_libname->name,
-			  (int) sizeof l->l_map_start * 2,
-			  (size_t) l->l_map_start);
+	      _dl_printf ("\t%s => not found\n",  l->l_libname->name);
 	    else
-	      _dl_printf ("\t%s => %s (0x%0*Zx)\n", l->l_libname->name,
-			  l->l_name, (int) sizeof l->l_map_start * 2,
+	      _dl_printf ("\t%s => %s (0x%0*Zx)\n",
+			  DSO_FILENAME (l->l_libname->name),
+			  DSO_FILENAME (l->l_name),
+			  (int) sizeof l->l_map_start * 2,
 			  (size_t) l->l_map_start);
+	  }
 	}
 
       if (__glibc_unlikely (state.mode != rtld_mode_trace))
@@ -2676,7 +2676,11 @@ process_envvars (struct dl_main_state *state)
 	case 20:
 	  /* The mode of the dynamic linker can be set.  */
 	  if (memcmp (envline, "TRACE_LOADED_OBJECTS", 20) == 0)
-	    state->mode = rtld_mode_trace;
+	    {
+	      state->mode = rtld_mode_trace;
+	      state->mode_trace_program
+		= _dl_strtoul (&envline[21], NULL) > 1;
+	    }
 	  break;
 
 	  /* We might have some extra environment variable to handle.  This