Status: submitted similar patch 2004-12-08

 This patch cleans up the initialization of thread_db.  It works for static

 binaries now.  The vsyscall patches hide this problem, since new static

 binaries will load the vsyscall DSO and then trigger thread_db; but

 this is still a good cleanup.

 Index: gdb-6.3/gdb/thread-db.c

 ===================================================================

 --- gdb-6.3.orig/gdb/thread-db.c	2004-10-08 16:29:56.000000000 -0400

 +++ gdb-6.3/gdb/thread-db.c	2004-11-10 00:19:30.626530413 -0500

 @@ -34,6 +34,7 @@

  #include "target.h"

  #include "regcache.h"

  #include "solib-svr4.h"

 +#include "observer.h"

  #ifdef HAVE_GNU_LIBC_VERSION_H

  #include <gnu/libc-version.h>

 @@ -627,59 +628,49 @@ check_thread_signals (void)

  #endif

  }

 +/* Check whether thread_db is usable.  This function is called when

 +   an inferior is created (or otherwise acquired, e.g. attached to)

 +   and when new shared libraries are loaded into a running process.  */

 +

  static void

 -thread_db_new_objfile (struct objfile *objfile)

 +check_for_thread_db (void)

  {

    td_err_e err;

 +  static int already_loaded;

    /* First time through, report that libthread_db was successfuly

       loaded.  Can't print this in in thread_db_load as, at that stage,

 -     the interpreter and it's console haven't started.  The real

 -     problem here is that libthread_db is loaded too early - it should

 -     only be loaded when there is a program to debug.  */

 -  {

 -    static int dejavu;

 -    if (!dejavu)

 -      {

 -	Dl_info info;

 -	const char *library = NULL;

 -	/* Try dladdr.  */

 -	if (dladdr ((*td_ta_new_p), &info) != 0)

 -	  library = info.dli_fname;

 -	/* Try dlinfo?  */

 -	if (library == NULL)

 -	  /* Paranoid - don't let a NULL path slip through.  */

 -	  library = LIBTHREAD_DB_SO;

 -	printf_unfiltered ("Using host libthread_db library \"%s\".\n",

 -			   library);

 -	dejavu = 1;

 -      }

 -  }

 +     the interpreter and it's console haven't started.  */

 -  /* Don't attempt to use thread_db on targets which can not run

 -     (core files).  */

 -  if (objfile == NULL || !target_has_execution)

 +  if (!already_loaded)

      {

 -      /* All symbols have been discarded.  If the thread_db target is

 -         active, deactivate it now.  */

 -      if (using_thread_db)

 -	{

 -	  gdb_assert (proc_handle.pid == 0);

 -	  unpush_target (&thread_db_ops);

 -	  using_thread_db = 0;

 -	}

 +      Dl_info info;

 +      const char *library = NULL;

 +      if (dladdr ((*td_ta_new_p), &info) != 0)

 +	library = info.dli_fname;

 +

 +      /* Try dlinfo?  */

 -      goto quit;

 +      if (library == NULL)

 +	/* Paranoid - don't let a NULL path slip through.  */

 +	library = LIBTHREAD_DB_SO;

 +

 +      printf_unfiltered ("Using host libthread_db library \"%s\".\n",

 +			 library);

 +      already_loaded = 1;

      }

    if (using_thread_db)

      /* Nothing to do.  The thread library was already detected and the

         target vector was already activated.  */

 -    goto quit;

 +    return;

 +

 +  /* Don't attempt to use thread_db on targets which can not run

 +     (executables not running yet, core files) for now.  */

 +  if (!target_has_execution)

 +    return;

 -  /* Initialize the structure that identifies the child process.  Note

 -     that at this point there is no guarantee that we actually have a

 -     child process.  */

 +  /* Initialize the structure that identifies the child process.  */

    proc_handle.pid = GET_PID (inferior_ptid);

    /* Now attempt to open a connection to the thread library.  */

 @@ -706,12 +697,24 @@ thread_db_new_objfile (struct objfile *o

  	       thread_db_err_str (err));

        break;

      }

 +}

 +

 +static void

 +thread_db_new_objfile (struct objfile *objfile)

 +{

 +  if (objfile != NULL)

 +    check_for_thread_db ();

 -quit:

    if (target_new_objfile_chain)

      target_new_objfile_chain (objfile);

  }

 +static void

 +check_for_thread_db_observer (struct target_ops *target, int from_tty)

 +{

 +  check_for_thread_db ();

 +}

 +

  /* Attach to a new thread.  This function is called when we receive a

     TD_CREATE event or when we iterate over all threads and find one

     that wasn't already in our list.  */

 @@ -1366,5 +1369,8 @@ _initialize_thread_db (void)

        /* Add ourselves to objfile event chain.  */

        target_new_objfile_chain = deprecated_target_new_objfile_hook;

        deprecated_target_new_objfile_hook = thread_db_new_objfile;

 +

 +      /* Register ourselves for the new inferior observer.  */

 +      observer_attach_inferior_created (check_for_thread_db_observer);

      }

  }

 Index: gdb-6.3/gdb/Makefile.in

 ===================================================================

 --- gdb-6.3.orig/gdb/Makefile.in	2004-11-09 23:04:57.000000000 -0500

 +++ gdb-6.3/gdb/Makefile.in	2004-11-10 00:19:26.440347022 -0500

 @@ -2626,7 +2626,8 @@ thread.o: thread.c $(defs_h) $(symtab_h)

  	$(gdbcmd_h) $(regcache_h) $(gdb_h) $(gdb_string_h) $(ui_out_h)

  thread-db.o: thread-db.c $(defs_h) $(gdb_assert_h) $(gdb_proc_service_h) \

  	$(gdb_thread_db_h) $(bfd_h) $(gdbthread_h) $(inferior_h) \

 -	$(symfile_h) $(objfiles_h) $(target_h) $(regcache_h) $(solib_svr4_h)

 +	$(symfile_h) $(objfiles_h) $(target_h) $(regcache_h) $(solib_svr4_h) \

 +	$(observer_h)

  top.o: top.c $(defs_h) $(gdbcmd_h) $(call_cmds_h) $(cli_cmds_h) \

  	$(cli_script_h) $(cli_setshow_h) $(cli_decode_h) $(symtab_h) \

  	$(inferior_h) $(target_h) $(breakpoint_h) $(gdbtypes_h) \