drd/drd_cond.c

/* -*- mode: C; c-basic-offset: 3; -*- */
/*
  This file is part of drd, a thread error detector.

  Copyright (C) 2006-2009 Bart Van Assche <bart.vanassche@gmail.com>.

  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 "drd_clientobj.h"
#include "drd_cond.h"
#include "drd_error.h"
#include "drd_mutex.h"
#include "drd_suppression.h"
#include "pub_tool_errormgr.h"    /* VG_(maybe_record_error)() */
#include "pub_tool_libcassert.h"  /* tl_assert()               */
#include "pub_tool_libcprint.h"   /* VG_(printf)()             */
#include "pub_tool_machine.h"     /* VG_(get_IP)()             */
#include "pub_tool_options.h"     /* VG_(clo_backtrace_size)   */
#include "pub_tool_threadstate.h" /* VG_(get_running_tid)()    */


/* Local functions. */

static void DRD_(cond_cleanup)(struct cond_info* p);


/* Local variables. */

static Bool DRD_(s_report_signal_unlocked) = True;
static Bool DRD_(s_trace_cond);


/* Function definitions. */

void DRD_(cond_set_report_signal_unlocked)(const Bool r)
{
   DRD_(s_report_signal_unlocked) = r;
}

void DRD_(cond_set_trace)(const Bool trace_cond)
{
   DRD_(s_trace_cond) = trace_cond;
}

static
void DRD_(cond_initialize)(struct cond_info* const p, const Addr cond)
{
   tl_assert(cond != 0);
   tl_assert(p->a1         == cond);
   tl_assert(p->type       == ClientCondvar);

   p->cleanup       = (void(*)(DrdClientobj*))(DRD_(cond_cleanup));
   p->delete_thread = 0;
   p->waiter_count  = 0;
   p->mutex         = 0;
}

/**
 * Free the memory that was allocated by cond_initialize(). Called by
 * DRD_(clientobj_remove)().
 */
static void DRD_(cond_cleanup)(struct cond_info* p)
{
   tl_assert(p);
   if (p->mutex)
   {
      struct mutex_info* q;
      q = &(DRD_(clientobj_get)(p->mutex, ClientMutex)->mutex);
      tl_assert(q);
      {
         CondDestrErrInfo cde = { p->a1, q->a1, q->owner };
         VG_(maybe_record_error)(VG_(get_running_tid)(),
                                 CondDestrErr,
                                 VG_(get_IP)(VG_(get_running_tid)()),
                                 "Destroying condition variable that is being"
                                 " waited upon",
                                 &cde);
      }
   }
}

static struct cond_info* DRD_(cond_get_or_allocate)(const Addr cond)
{
   struct cond_info *p;

   tl_assert(offsetof(DrdClientobj, cond) == 0);
   p = &(DRD_(clientobj_get)(cond, ClientCondvar)->cond);
   if (p == 0)
   {
      p = &(DRD_(clientobj_add)(cond, ClientCondvar)->cond);
      DRD_(cond_initialize)(p, cond);
   }
   return p;
}

static struct cond_info* DRD_(cond_get)(const Addr cond)
{
   tl_assert(offsetof(DrdClientobj, cond) == 0);
   return &(DRD_(clientobj_get)(cond, ClientCondvar)->cond);
}

/** Called before pthread_cond_init(). */
void DRD_(cond_pre_init)(const Addr cond)
{
   struct cond_info* p;

   if (DRD_(s_trace_cond))
   {
      VG_(message)(Vg_UserMsg,
                   "[%d/%d] cond_init       cond 0x%lx",
                   VG_(get_running_tid)(),
                   DRD_(thread_get_running_tid)(),
                   cond);
   }

   p = DRD_(cond_get)(cond);

   if (p)
   {
      CondErrInfo cei = { .cond = cond };
      VG_(maybe_record_error)(VG_(get_running_tid)(),
                              CondErr,
                              VG_(get_IP)(VG_(get_running_tid)()),
                              "initialized twice",
                              &cei);
   }

   p = DRD_(cond_get_or_allocate)(cond);
}

/** Called after pthread_cond_destroy(). */
void DRD_(cond_post_destroy)(const Addr cond)
{
   struct cond_info* p;

   if (DRD_(s_trace_cond))
   {
      VG_(message)(Vg_UserMsg,
                   "[%d/%d] cond_destroy    cond 0x%lx",
                   VG_(get_running_tid)(),
                   DRD_(thread_get_running_tid)(),
                   cond);
   }

   p = DRD_(cond_get)(cond);
   if (p == 0)
   {
      CondErrInfo cei = { .cond = cond };
      VG_(maybe_record_error)(VG_(get_running_tid)(),
                              CondErr,
                              VG_(get_IP)(VG_(get_running_tid)()),
                              "not a condition variable",
                              &cei);
      return;
   }

   if (p->waiter_count != 0)
   {
      CondErrInfo cei = { .cond = cond };
      VG_(maybe_record_error)(VG_(get_running_tid)(),
                              CondErr,
                              VG_(get_IP)(VG_(get_running_tid)()),
                              "destruction of condition variable being waited"
                              " upon",
                              &cei);
   }

   DRD_(clientobj_remove)(p->a1, ClientCondvar);
}

/** Called before pthread_cond_wait(). Note: before this function is called,
 *  mutex_unlock() has already been called from drd_clientreq.c.
 */
int DRD_(cond_pre_wait)(const Addr cond, const Addr mutex)
{
   struct cond_info* p;
   struct mutex_info* q;

   if (DRD_(s_trace_cond))
   {
      VG_(message)(Vg_UserMsg,
                   "[%d/%d] cond_pre_wait   cond 0x%lx",
                   VG_(get_running_tid)(),
                   DRD_(thread_get_running_tid)(),
                   cond);
   }

   p = DRD_(cond_get_or_allocate)(cond);
   tl_assert(p);

   if (p->waiter_count == 0)
   {
      p->mutex = mutex;
   }
   else if (p->mutex != mutex)
   {
      CondWaitErrInfo cwei
         = { .cond = cond, .mutex1 = p->mutex, .mutex2 = mutex };
      VG_(maybe_record_error)(VG_(get_running_tid)(),
                              CondWaitErr,
                              VG_(get_IP)(VG_(get_running_tid)()),
                              "Inconsistent association of condition variable"
                              " and mutex",
                              &cwei);
   }
   tl_assert(p->mutex);
   q = DRD_(mutex_get)(p->mutex);
   if (q
       && q->owner == DRD_(thread_get_running_tid)() && q->recursion_count > 0)
   {
      const ThreadId vg_tid = VG_(get_running_tid)();
      MutexErrInfo MEI = { q->a1, q->recursion_count, q->owner };
      VG_(maybe_record_error)(vg_tid,
                              MutexErr,
                              VG_(get_IP)(vg_tid),
                              "Mutex locked recursively",
                              &MEI);
   }
   else if (q == 0)
   {
      DRD_(not_a_mutex)(p->mutex);
   }

   return ++p->waiter_count;
}

/** Called after pthread_cond_wait(). */
int DRD_(cond_post_wait)(const Addr cond)
{
   struct cond_info* p;

   if (DRD_(s_trace_cond))
   {
      VG_(message)(Vg_UserMsg,
                   "[%d/%d] cond_post_wait  cond 0x%lx",
                   VG_(get_running_tid)(),
                   DRD_(thread_get_running_tid)(),
                   cond);
   }

   p = DRD_(cond_get)(cond);
   if (p)
   {
      if (p->waiter_count > 0)
      {
         --p->waiter_count;
         if (p->waiter_count == 0)
         {
            p->mutex = 0;
         }
      }
      return p->waiter_count;
   }
   return 0;
}

static void DRD_(cond_signal)(Addr const cond)
{
   const ThreadId vg_tid = VG_(get_running_tid)();
   const DrdThreadId drd_tid = DRD_(VgThreadIdToDrdThreadId)(vg_tid);
   struct cond_info* const cond_p = DRD_(cond_get)(cond);

   if (cond_p && cond_p->waiter_count > 0)
   {
      if (DRD_(s_report_signal_unlocked)
          && ! DRD_(mutex_is_locked_by)(cond_p->mutex, drd_tid))
      {
         /* A signal is sent while the associated mutex has not been locked. */
         /* This can indicate but is not necessarily a race condition.       */
         CondRaceErrInfo cei;
         cei.cond  = cond;
         cei.mutex = cond_p->mutex;
         VG_(maybe_record_error)(vg_tid,
                                 CondRaceErr,
                                 VG_(get_IP)(vg_tid),
                                 "CondErr",
                                 &cei);
      }
   }
   else
   {
      /* No other thread is waiting for the signal, hence the signal will be */
      /* lost. This is normal in a POSIX threads application.                */
   }
}

/** Called before pthread_cond_signal(). */
void DRD_(cond_pre_signal)(Addr const cond)
{
   if (DRD_(s_trace_cond))
   {
      VG_(message)(Vg_UserMsg,
                   "[%d/%d] cond_signal     cond 0x%lx",
                   VG_(get_running_tid)(),
                   DRD_(thread_get_running_tid)(),
                   cond);
   }

   DRD_(cond_signal)(cond);
}

/** Called before pthread_cond_broadcast(). */
void DRD_(cond_pre_broadcast)(Addr const cond)
{
   if (DRD_(s_trace_cond))
   {
      VG_(message)(Vg_UserMsg,
                   "[%d/%d] cond_broadcast  cond 0x%lx",
                   VG_(get_running_tid)(),
                   DRD_(thread_get_running_tid)(),
                   cond);
   }

   DRD_(cond_signal)(cond);
}