coregrind/linux/core_os.c

/*--------------------------------------------------------------------*/
/*--- OS-specific stuff.                           linux/core_os.c ---*/
/*--------------------------------------------------------------------*/

/*
   This file is part of Valgrind, a dynamic binary instrumentation
   framework.

   Copyright (C) 2000-2005 Nicholas Nethercote
      njn@valgrind.org

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307, USA.

   The GNU General Public License is contained in the file COPYING.
*/

#include "core.h"
#include "pub_core_libcbase.h"
#include "pub_core_debuglog.h"
#include "pub_core_libcassert.h"
#include "pub_core_libcprint.h"
#include "pub_core_libcsignal.h"
#include "pub_core_options.h"
#include "pub_core_signals.h"
#include "pub_core_tooliface.h"

void VGO_(os_state_clear)(ThreadState *tst)
{
   tst->os_state.lwpid = 0;
   tst->os_state.threadgroup = 0;
}

void VGO_(os_state_init)(ThreadState *tst)
{
   tst->os_state.valgrind_stack_base = 0;
   tst->os_state.valgrind_stack_szB  = 0;

   VGO_(os_state_clear)(tst);
}

static Bool i_am_the_only_thread ( void )
{
   Int c = VG_(count_living_threads)();
   vg_assert(c >= 1); /* stay sane */
   return c == 1;
}


void VGO_(terminate_NORETURN)(ThreadId tid, VgSchedReturnCode src)
{
   VG_(debugLog)(1, "core_os", 
                    "VGO_(terminate_NORETURN)(tid=%lld)\n", (ULong)tid);

   vg_assert(VG_(count_living_threads)() == 0);

   //--------------------------------------------------------------
   // Exit, according to the scheduler's return code
   //--------------------------------------------------------------
   switch (src) {
   case VgSrc_ExitSyscall: /* the normal way out */
      VG_(exit)( VG_(threads)[tid].os_state.exitcode );
      /* NOT ALIVE HERE! */
      VG_(core_panic)("entered the afterlife in main() -- ExitSyscall");
      break; /* what the hell :) */

   case VgSrc_FatalSig:
      /* We were killed by a fatal signal, so replicate the effect */
      vg_assert(VG_(threads)[tid].os_state.fatalsig != 0);
      VG_(kill_self)(VG_(threads)[tid].os_state.fatalsig);
      VG_(core_panic)("main(): signal was supposed to be fatal");
      break;

   default:
      VG_(core_panic)("main(): unexpected scheduler return code");
   }
}


/* Run a thread from beginning to end and return the thread's
   scheduler-return-code. */

VgSchedReturnCode VGO_(thread_wrapper)(Word /*ThreadId*/ tidW)
{
   VG_(debugLog)(1, "core_os", 
                    "VGO_(thread_wrapper)(tid=%lld): entry\n", 
                    (ULong)tidW);

   VgSchedReturnCode ret;
   ThreadId     tid = (ThreadId)tidW;
   ThreadState* tst = VG_(get_ThreadState)(tid);

   vg_assert(tst->status == VgTs_Init);

   /* make sure we get the CPU lock before doing anything significant */
   VG_(set_running)(tid);

   if (0)
      VG_(printf)("thread tid %d started: stack = %p\n",
		  tid, &tid);

   VG_TRACK ( post_thread_create, tst->os_state.parent, tid );

   tst->os_state.lwpid = VG_(gettid)();
   tst->os_state.threadgroup = VG_(getpid)();

   /* Thread created with all signals blocked; scheduler will set the
      appropriate mask */

   ret = VG_(scheduler)(tid);

   vg_assert(VG_(is_exiting)(tid));
   
   vg_assert(tst->status == VgTs_Runnable);
   vg_assert(VG_(is_running_thread)(tid));

   VG_(debugLog)(1, "core_os", 
                    "VGO_(thread_wrapper)(tid=%lld): done\n", 
                    (ULong)tidW);

   /* Return to caller, still holding the lock. */
   return ret;
}


/* Wait until all other threads disappear. */
void VGA_(reap_threads)(ThreadId self)
{
   while (!i_am_the_only_thread()) {
      /* Let other thread(s) run */
      VG_(vg_yield)();
      VG_(poll_signals)(self);
   }
   vg_assert(i_am_the_only_thread());
}

/* The we need to know the address of it so it can be
   called at program exit. */
static Addr __libc_freeres_wrapper;

void VGA_(intercept_libc_freeres_wrapper)(Addr addr)
{
   __libc_freeres_wrapper = addr;
}

/* Final clean-up before terminating the process.  
   Clean up the client by calling __libc_freeres() (if requested) */
void VGA_(final_tidyup)(ThreadId tid)
{
   vg_assert(VG_(is_running_thread)(tid));
   
   if (!VG_(needs).libc_freeres ||
       !VG_(clo_run_libc_freeres) ||
       __libc_freeres_wrapper == 0)
      return;			/* can't/won't do it */

   if (VG_(clo_verbosity) > 2  ||
       VG_(clo_trace_syscalls) ||
       VG_(clo_trace_sched))
      VG_(message)(Vg_DebugMsg, 
		   "Caught __NR_exit; running __libc_freeres()");
      
   /* point thread context to point to libc_freeres_wrapper */
   INSTR_PTR(VG_(threads)[tid].arch) = __libc_freeres_wrapper;
   // XXX should we use a special stack?

   /* Block all blockable signals by copying the real block state into
      the thread's block state*/
   VG_(sigprocmask)(VKI_SIG_BLOCK, NULL, &VG_(threads)[tid].sig_mask);
   VG_(threads)[tid].tmp_sig_mask = VG_(threads)[tid].sig_mask;

   /* and restore handlers to default */
   VG_(set_default_handler)(VKI_SIGSEGV);
   VG_(set_default_handler)(VKI_SIGBUS);
   VG_(set_default_handler)(VKI_SIGILL);
   VG_(set_default_handler)(VKI_SIGFPE);

   // We were exiting, so assert that...
   vg_assert(VG_(is_exiting)(tid));
   // ...but now we're not again
   VG_(threads)[tid].exitreason = VgSrc_None;

   // run until client thread exits - ideally with LIBC_FREERES_DONE,
   // but exit/exitgroup/signal will do
   VG_(scheduler)(tid);

   vg_assert(VG_(is_exiting)(tid));
}

// Arch-specific client requests
Bool VGA_(client_request)(ThreadId tid, UWord *args)
{
   Bool handled = True;

   vg_assert(VG_(is_running_thread)(tid));

   switch(args[0]) {
   case VG_USERREQ__LIBC_FREERES_DONE:
      /* This is equivalent to an exit() syscall, but we don't set the
	 exitcode (since it might already be set) */
      if (0 || VG_(clo_trace_syscalls) || VG_(clo_trace_sched))
	 VG_(message)(Vg_DebugMsg, 
		      "__libc_freeres() done; really quitting!");
      VG_(threads)[tid].exitreason = VgSrc_ExitSyscall;
      break;

   default:
      handled = False;
      break;
   }

   return handled;
}

/*--------------------------------------------------------------------*/
/*--- end                                                          ---*/
/*--------------------------------------------------------------------*/