memcheck/mac_malloc_wrappers.c

/*--------------------------------------------------------------------*/
/*--- malloc/free wrappers for detecting errors and updating bits. ---*/
/*---                                        mac_malloc_wrappers.c ---*/
/*--------------------------------------------------------------------*/

/*
   This file is part of MemCheck, a heavyweight Valgrind tool for
   detecting memory errors, and AddrCheck, a lightweight Valgrind tool 
   for detecting memory errors.

   Copyright (C) 2000-2003 Julian Seward 
      jseward@acm.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 "mac_shared.h"

/*------------------------------------------------------------*/
/*--- Defns                                                ---*/
/*------------------------------------------------------------*/

/* Stats ... */
static UInt cmalloc_n_mallocs  = 0;
static UInt cmalloc_n_frees    = 0;
static UInt cmalloc_bs_mallocd = 0;

/* We want a 16B redzone on heap blocks for Addrcheck and Memcheck */
UInt VG_(vg_malloc_redzone_szB) = 16;

/* Function pointers for the two skins to track interesting events. */
void (*MAC_(new_mem_heap)) ( Addr a, UInt len, Bool is_inited )  = NULL;
void (*MAC_(ban_mem_heap)) ( Addr a, UInt len )                  = NULL;
void (*MAC_(die_mem_heap)) ( Addr a, UInt len )                  = NULL;
void (*MAC_(copy_mem_heap))( Addr from, Addr to, UInt len )      = NULL;

/* Function pointers for internal sanity checking. */
Bool (*MAC_(check_noaccess))( Addr a, UInt len, Addr* bad_addr ) = NULL;


/*------------------------------------------------------------*/
/*--- Tracking malloc'd and free'd blocks                  ---*/
/*------------------------------------------------------------*/

/* Record malloc'd blocks.  Nb: Addrcheck and Memcheck construct this
   separately in their respective initialisation functions. */
VgHashTable MAC_(malloc_list) = NULL;
   
/* Records blocks after freeing. */
static MAC_Chunk* freed_list_start  = NULL;
static MAC_Chunk* freed_list_end    = NULL;
static Int        freed_list_volume = 0;

/* Put a shadow chunk on the freed blocks queue, possibly freeing up
   some of the oldest blocks in the queue at the same time. */
static void add_to_freed_queue ( MAC_Chunk* mc )
{
   MAC_Chunk* sc1;

   /* Put it at the end of the freed list */
   if (freed_list_end == NULL) {
      sk_assert(freed_list_start == NULL);
      freed_list_end    = freed_list_start = mc;
      freed_list_volume = mc->size;
   } else {
      sk_assert(freed_list_end->next == NULL);
      freed_list_end->next = mc;
      freed_list_end       = mc;
      freed_list_volume += mc->size;
   }
   mc->next = NULL;

   /* Release enough of the oldest blocks to bring the free queue
      volume below vg_clo_freelist_vol. */

   while (freed_list_volume > MAC_(clo_freelist_vol)) {
      sk_assert(freed_list_start != NULL);
      sk_assert(freed_list_end != NULL);

      sc1 = freed_list_start;
      freed_list_volume -= sc1->size;
      /* VG_(printf)("volume now %d\n", freed_list_volume); */
      sk_assert(freed_list_volume >= 0);

      if (freed_list_start == freed_list_end) {
         freed_list_start = freed_list_end = NULL;
      } else {
         freed_list_start = sc1->next;
      }
      sc1->next = NULL; /* just paranoia */

      /* free MAC_Chunk */
      VG_(cli_free) ( (void*)(sc1->data) );
      VG_(free) ( sc1 );
   }
}

/* Return the first shadow chunk satisfying the predicate p. */
MAC_Chunk* MAC_(first_matching_freed_MAC_Chunk) ( Bool (*p)(MAC_Chunk*) )
{
   MAC_Chunk* mc;

   /* No point looking through freed blocks if we're not keeping
      them around for a while... */
   for (mc = freed_list_start; mc != NULL; mc = mc->next)
      if (p(mc))
         return mc;

   return NULL;
}

/* Allocate its shadow chunk, put it on the appropriate list. */
static
void add_MAC_Chunk ( Addr p, UInt size, MAC_AllocKind kind )
{
   MAC_Chunk* mc;

   mc            = VG_(malloc)(sizeof(MAC_Chunk));
   mc->data      = p;
   mc->size      = size;
   mc->allockind = kind;
   mc->where     = VG_(get_ExeContext)(VG_(get_current_or_recent_tid)());

   /* Paranoia ... ensure this area is off-limits to the client, so
      the mc->data field isn't visible to the leak checker.  If memory
      management is working correctly, anything pointer returned by
      VG_(malloc) should be noaccess as far as the client is
      concerned. */
   if (!MAC_(check_noaccess)( (Addr)mc, sizeof(MAC_Chunk), NULL )) {
      VG_(skin_panic)("add_MAC_chunk: shadow area is accessible");
   } 

   VG_(HT_add_node)( MAC_(malloc_list), (VgHashNode*)mc );
}

/*------------------------------------------------------------*/
/*--- client_malloc(), etc                                 ---*/
/*------------------------------------------------------------*/

/* Allocate memory and note change in memory available */
__inline__
void MAC_(new_block) ( Addr p, UInt size,
                       UInt rzB, Bool is_zeroed, MAC_AllocKind kind )
{
   VGP_PUSHCC(VgpCliMalloc);

   cmalloc_n_mallocs ++;
   cmalloc_bs_mallocd += size;

   add_MAC_Chunk( p, size, kind );

   MAC_(ban_mem_heap)( p-rzB, rzB );
   MAC_(new_mem_heap)( p, size, is_zeroed );
   MAC_(ban_mem_heap)( p+size, rzB );

   VGP_POPCC(VgpCliMalloc);
}

void* SK_(malloc) ( Int n )
{
   if (n < 0) {
      VG_(message)(Vg_UserMsg, "Warning: silly arg (%d) to malloc()", n );
      return NULL;
   } else {
      Addr p = (Addr)VG_(cli_malloc)( VG_(clo_alignment), n );
      MAC_(new_block) ( p, n, VG_(vg_malloc_redzone_szB),
                        /*is_zeroed*/False, MAC_AllocMalloc );
      return (void*)p;
   }
}

void* SK_(__builtin_new) ( Int n )
{
   if (n < 0) {
      VG_(message)(Vg_UserMsg, "Warning: silly arg (%d) to __builtin_new()", n);
      return NULL;
   } else {
      Addr p = (Addr)VG_(cli_malloc)( VG_(clo_alignment), n );
      MAC_(new_block) ( p, n, VG_(vg_malloc_redzone_szB),
                        /*is_zeroed*/False, MAC_AllocNew );
      return (void*)p;
   }
}

void* SK_(__builtin_vec_new) ( Int n )
{
   if (n < 0) {
      VG_(message)(Vg_UserMsg, 
                   "Warning: silly arg (%d) to __builtin_vec_new()", n );
      return NULL;
   } else {
      Addr p = (Addr)VG_(cli_malloc)( VG_(clo_alignment), n );
      MAC_(new_block) ( p, n, VG_(vg_malloc_redzone_szB),
                        /*is_zeroed*/False, MAC_AllocNewVec );
      return (void*)p;
   }
}

void* SK_(memalign) ( Int align, Int n )
{
   if (n < 0) {
      VG_(message)(Vg_UserMsg, "Warning: silly arg (%d) to memalign()", n);
      return NULL;
   } else {
      Addr p = (Addr)VG_(cli_malloc)( align, n );
      MAC_(new_block) ( p, n, VG_(vg_malloc_redzone_szB),
                        /*is_zeroed*/False, MAC_AllocMalloc );
      return (void*)p;
   }
}

void* SK_(calloc) ( Int nmemb, Int size1 )
{
   Int   n, i;

   n = nmemb * size1;

   if (nmemb < 0 || size1 < 0) {
      VG_(message)(Vg_UserMsg, "Warning: silly args (%d,%d) to calloc()",
                               nmemb, size1 );
      return NULL;
   } else {
      Addr p = (Addr)VG_(cli_malloc)( VG_(clo_alignment), n );
      MAC_(new_block) ( p, n, VG_(vg_malloc_redzone_szB),
                        /*is_zeroed*/True, MAC_AllocMalloc );
      for (i = 0; i < n; i++) 
         ((UChar*)p)[i] = 0;
      return (void*)p;
   }
}

static
void die_and_free_mem ( MAC_Chunk* mc,
                        MAC_Chunk** prev_chunks_next_ptr, UInt rzB )
{
   /* Note: ban redzones again -- just in case user de-banned them
      with a client request... */
   MAC_(ban_mem_heap)( mc->data-rzB, rzB );
   MAC_(die_mem_heap)( mc->data, mc->size );
   MAC_(ban_mem_heap)( mc->data+mc->size, rzB );

   /* Remove mc from the malloclist using prev_chunks_next_ptr to
      avoid repeating the hash table lookup.  Can't remove until at least
      after free and free_mismatch errors are done because they use
      describe_addr() which looks for it in malloclist. */
   *prev_chunks_next_ptr = mc->next;

   /* Record where freed */
   mc->where = VG_(get_ExeContext) ( VG_(get_current_or_recent_tid)() );

   /* Put it out of harm's way for a while, if not from a client request */
   if (MAC_AllocCustom != mc->allockind)
      add_to_freed_queue ( mc );
   else
      VG_(free) ( mc );
}


__inline__
void MAC_(handle_free) ( Addr p, UInt rzB, MAC_AllocKind kind )
{
   MAC_Chunk*  mc;
   MAC_Chunk** prev_chunks_next_ptr;
   ThreadId    tid = VG_(get_current_or_recent_tid)();

   VGP_PUSHCC(VgpCliMalloc);

   cmalloc_n_frees++;

   mc = (MAC_Chunk*)VG_(HT_get_node) ( MAC_(malloc_list), (UInt)p,
                                       (VgHashNode***)&prev_chunks_next_ptr );
   if (mc == NULL) {
      MAC_(record_free_error) ( tid, p );
      VGP_POPCC(VgpCliMalloc);
      return;
   }

   /* check if its a matching free() / delete / delete [] */
   if (kind != mc->allockind) {
      MAC_(record_freemismatch_error) ( tid, p );
   }

   die_and_free_mem ( mc, prev_chunks_next_ptr, rzB );
   VGP_POPCC(VgpCliMalloc);
}

void SK_(free) ( void* p )
{
   MAC_(handle_free)((Addr)p, VG_(vg_malloc_redzone_szB), MAC_AllocMalloc);
}

void SK_(__builtin_delete) ( void* p )
{
   MAC_(handle_free)((Addr)p, VG_(vg_malloc_redzone_szB), MAC_AllocNew);
}

void SK_(__builtin_vec_delete) ( void* p )
{
   MAC_(handle_free)((Addr)p, VG_(vg_malloc_redzone_szB), MAC_AllocNewVec);
}

void* SK_(realloc) ( void* p, Int new_size )
{
   MAC_Chunk  *mc;
   MAC_Chunk **prev_chunks_next_ptr;
   UInt        i;
   ThreadId    tid = VG_(get_current_or_recent_tid)();

   VGP_PUSHCC(VgpCliMalloc);

   cmalloc_n_frees ++;
   cmalloc_n_mallocs ++;
   cmalloc_bs_mallocd += new_size;

   if (new_size < 0) {
      VG_(message)(Vg_UserMsg, 
                   "Warning: silly arg (%d) to realloc()", new_size );
      return NULL;
   }

   /* First try and find the block. */
   mc = (MAC_Chunk*)VG_(HT_get_node) ( MAC_(malloc_list), (UInt)p,
                                       (VgHashNode***)&prev_chunks_next_ptr );

   if (mc == NULL) {
      MAC_(record_free_error) ( tid, (Addr)p );
      /* Perhaps we should return to the program regardless. */
      VGP_POPCC(VgpCliMalloc);
      return NULL;
   }
  
   /* check if its a matching free() / delete / delete [] */
   if (MAC_AllocMalloc != mc->allockind) {
      /* can not realloc a range that was allocated with new or new [] */
      MAC_(record_freemismatch_error) ( tid, (Addr)p );
      /* but keep going anyway */
   }

   if (mc->size == new_size) {
      /* size unchanged */
      mc->where = VG_(get_ExeContext)(tid);
      VGP_POPCC(VgpCliMalloc);
      return p;
      
   } else if (mc->size > new_size) {
      /* new size is smaller */
      MAC_(die_mem_heap)( mc->data+new_size, mc->size-new_size );
      mc->size = new_size;
      mc->where = VG_(get_ExeContext)(tid);
      VGP_POPCC(VgpCliMalloc);
      return p;

   } else {
      /* new size is bigger */
      Addr p_new;

      /* Get new memory */
      p_new = (Addr)VG_(cli_malloc)(VG_(clo_alignment), new_size);

      /* First half kept and copied, second half new, 
         red zones as normal */
      MAC_(ban_mem_heap) ( p_new-VG_(vg_malloc_redzone_szB), 
                                 VG_(vg_malloc_redzone_szB) );
      MAC_(copy_mem_heap)( (Addr)p, p_new, mc->size );
      MAC_(new_mem_heap) ( p_new+mc->size, new_size-mc->size, /*inited*/False );
      MAC_(ban_mem_heap) ( p_new+new_size, VG_(vg_malloc_redzone_szB) );

      /* Copy from old to new */
      for (i = 0; i < mc->size; i++)
         ((UChar*)p_new)[i] = ((UChar*)p)[i];

      /* Free old memory */
      die_and_free_mem ( mc, prev_chunks_next_ptr,
                         VG_(vg_malloc_redzone_szB) );

      /* this has to be after die_and_free_mem, otherwise the
         former succeeds in shorting out the new block, not the
         old, in the case when both are on the same list.  */
      add_MAC_Chunk ( p_new, new_size, MAC_AllocMalloc );

      VGP_POPCC(VgpCliMalloc);
      return (void*)p_new;
   }  
}

void MAC_(print_malloc_stats) ( void )
{
   UInt nblocks = 0, nbytes = 0;
   
   /* Mmm... more lexical scoping */
   void count_one_chunk(VgHashNode* node) {
      MAC_Chunk* mc = (MAC_Chunk*)node;
      nblocks ++;
      nbytes  += mc->size;
   }

   if (VG_(clo_verbosity) == 0)
      return;

   /* Count memory still in use. */
   VG_(HT_apply_to_all_nodes)(MAC_(malloc_list), count_one_chunk);

   VG_(message)(Vg_UserMsg, 
                "malloc/free: in use at exit: %d bytes in %d blocks.",
                nbytes, nblocks);
   VG_(message)(Vg_UserMsg, 
                "malloc/free: %d allocs, %d frees, %u bytes allocated.",
                cmalloc_n_mallocs,
                cmalloc_n_frees, cmalloc_bs_mallocd);
   if (VG_(clo_verbosity) > 1)
      VG_(message)(Vg_UserMsg, "");
}

/*--------------------------------------------------------------------*/
/*--- end                                    mac_malloc_wrappers.c ---*/
/*--------------------------------------------------------------------*/