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/* Mudflap: narrow-pointer bounds-checking by tree rewriting.

   Copyright (C) 2002, 2003, 2004, 2009 Free Software Foundation, Inc.

   Contributed by Frank Ch. Eigler <fche@redhat.com>

   and Graydon Hoare <graydon@redhat.com>

This file is part of GCC.

GCC 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 3, or (at your option) any later

version.

GCC 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.

Under Section 7 of GPL version 3, you are granted additional

permissions described in the GCC Runtime Library Exception, version

3.1, as published by the Free Software Foundation.

You should have received a copy of the GNU General Public License and

a copy of the GCC Runtime Library Exception along with this program;

see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see

<http://www.gnu.org/licenses/>.  */

#include "config.h"

#ifndef HAVE_SOCKLEN_T

#define socklen_t int

#endif

/* These attempt to coax various unix flavours to declare all our

   needed tidbits in the system headers.  */

#if !defined(__FreeBSD__)  && !defined(__APPLE__)

#define _POSIX_SOURCE

#endif /* Some BSDs break <sys/socket.h> if this is defined. */

#define _GNU_SOURCE

#define _XOPEN_SOURCE

#define _BSD_TYPES

#define __EXTENSIONS__

#define _ALL_SOURCE

#define _LARGE_FILE_API

#define _XOPEN_SOURCE_EXTENDED 1

#include <string.h>

#include <stdio.h>

#include <stdlib.h>

#include <sys/time.h>

#include <sys/types.h>

#include <unistd.h>

#include <assert.h>

#include <errno.h>

#include <limits.h>

#include <time.h>

#include "mf-runtime.h"

#include "mf-impl.h"

#ifdef _MUDFLAP

#error "Do not compile this file with -fmudflap!"

#endif

/* Memory allocation related hook functions.  Some of these are

   intercepted via linker wrapping or symbol interposition.  Others

   use plain macros in mf-runtime.h.  */

#if PIC

enum { BS = 4096, NB=10 };

static char __mf_0fn_bufs[NB][BS];

static unsigned __mf_0fn_bufs_used[NB];

/* A special bootstrap variant. */

void *

__mf_0fn_malloc (size_t c)

{

  unsigned i;

  for (i=0; i<NB; i++)

    {

      if (! __mf_0fn_bufs_used[i] && c < BS)

        {

          __mf_0fn_bufs_used[i] = 1;

          return & __mf_0fn_bufs[i][0];

        }

    }

  return NULL;

}

#endif

#undef malloc

WRAPPER(void *, malloc, size_t c)

{

  size_t size_with_crumple_zones;

  DECLARE(void *, malloc, size_t c);

  void *result;

  BEGIN_PROTECT (malloc, c);

  size_with_crumple_zones =

    CLAMPADD(c,CLAMPADD(__mf_opts.crumple_zone,

                        __mf_opts.crumple_zone));

  BEGIN_MALLOC_PROTECT ();

  result = (char *) CALL_REAL (malloc, size_with_crumple_zones);

  END_MALLOC_PROTECT ();

  if (LIKELY(result))

    {

      result += __mf_opts.crumple_zone;

      __mf_register (result, c, __MF_TYPE_HEAP, "malloc region");

      /* XXX: register __MF_TYPE_NOACCESS for crumple zones.  */

    }

  return result;

}

#ifdef PIC

/* A special bootstrap variant. */

void *

__mf_0fn_calloc (size_t c, size_t n)

{

  return __mf_0fn_malloc (c * n);

}

#endif

#undef calloc

WRAPPER(void *, calloc, size_t c, size_t n)

{

  size_t size_with_crumple_zones;

  DECLARE(void *, calloc, size_t, size_t);

  DECLARE(void *, malloc, size_t);

  DECLARE(void *, memset, void *, int, size_t);

  char *result;

  BEGIN_PROTECT (calloc, c, n);

  size_with_crumple_zones =

    CLAMPADD((c * n), /* XXX: CLAMPMUL */

             CLAMPADD(__mf_opts.crumple_zone,

                      __mf_opts.crumple_zone));

  BEGIN_MALLOC_PROTECT ();

  result = (char *) CALL_REAL (malloc, size_with_crumple_zones);

  END_MALLOC_PROTECT ();

  if (LIKELY(result))

    memset (result, 0, size_with_crumple_zones);

  if (LIKELY(result))

    {

      result += __mf_opts.crumple_zone;

      __mf_register (result, c*n /* XXX: clamp */, __MF_TYPE_HEAP_I, "calloc region");

      /* XXX: register __MF_TYPE_NOACCESS for crumple zones.  */

    }

  return result;

}

#if PIC

/* A special bootstrap variant. */

void *

__mf_0fn_realloc (void *buf, size_t c)

{

  return NULL;

}

#endif

#undef realloc

WRAPPER(void *, realloc, void *buf, size_t c)

{

  DECLARE(void * , realloc, void *, size_t);

  size_t size_with_crumple_zones;

  char *base = buf;

  unsigned saved_wipe_heap;

  char *result;

  BEGIN_PROTECT (realloc, buf, c);

  if (LIKELY(buf))

    base -= __mf_opts.crumple_zone;

  size_with_crumple_zones =

    CLAMPADD(c, CLAMPADD(__mf_opts.crumple_zone,

                         __mf_opts.crumple_zone));

  BEGIN_MALLOC_PROTECT ();

  result = (char *) CALL_REAL (realloc, base, size_with_crumple_zones);

  END_MALLOC_PROTECT ();

  /* Ensure heap wiping doesn't occur during this peculiar

     unregister/reregister pair.  */

  LOCKTH ();

  __mf_set_state (reentrant);

  saved_wipe_heap = __mf_opts.wipe_heap;

  __mf_opts.wipe_heap = 0;

  if (LIKELY(buf))

    __mfu_unregister (buf, 0, __MF_TYPE_HEAP_I);

  /* NB: underlying region may have been __MF_TYPE_HEAP. */

  if (LIKELY(result))

    {

      result += __mf_opts.crumple_zone;

      __mfu_register (result, c, __MF_TYPE_HEAP_I, "realloc region");

      /* XXX: register __MF_TYPE_NOACCESS for crumple zones.  */

    }

  /* Restore previous setting.  */

  __mf_opts.wipe_heap = saved_wipe_heap;

  __mf_set_state (active);

  UNLOCKTH ();

  return result;

}

#if PIC

/* A special bootstrap variant. */

void

__mf_0fn_free (void *buf)

{

  return;

}

#endif

#undef free

WRAPPER(void, free, void *buf)

{

  /* Use a circular queue to delay some number (__mf_opts.free_queue_length) of free()s.  */

  static void *free_queue [__MF_FREEQ_MAX];

  static unsigned free_ptr = 0;

  static int freeq_initialized = 0;

  DECLARE(void, free, void *);

  BEGIN_PROTECT (free, buf);

  if (UNLIKELY(buf == NULL))

    return;

#if PIC

  /* Check whether the given buffer might have come from a

     __mf_0fn_malloc/calloc call that for whatever reason was not

     redirected back to __mf_0fn_free.  If so, we just ignore the

     call. */

  if (UNLIKELY((uintptr_t) buf >= (uintptr_t) __mf_0fn_bufs &&

               (uintptr_t) buf < ((uintptr_t) __mf_0fn_bufs + sizeof(__mf_0fn_bufs))))

  {

    VERBOSE_TRACE ("skipping free of boot (0fn) alloc buffer %p\n", buf);

    return;

  }

#endif

  LOCKTH ();

  if (UNLIKELY(!freeq_initialized))

    {

      memset (free_queue, 0,

                     __MF_FREEQ_MAX * sizeof (void *));

      freeq_initialized = 1;

    }

  UNLOCKTH ();

  __mf_unregister (buf, 0, __MF_TYPE_HEAP_I);

  /* NB: underlying region may have been __MF_TYPE_HEAP. */

  if (UNLIKELY(__mf_opts.free_queue_length > 0))

    {

      char *freeme = NULL;

      LOCKTH ();

      if (free_queue [free_ptr] != NULL)

        {

          freeme = free_queue [free_ptr];

          freeme -= __mf_opts.crumple_zone;

        }

      free_queue [free_ptr] = buf;

      free_ptr = (free_ptr == (__mf_opts.free_queue_length-1) ? 0 : free_ptr + 1);

      UNLOCKTH ();

      if (freeme)

        {

          if (__mf_opts.trace_mf_calls)

            {

              VERBOSE_TRACE ("freeing deferred pointer %p (crumple %u)\n",

                             (void *) freeme,

                             __mf_opts.crumple_zone);

            }

          BEGIN_MALLOC_PROTECT ();

          CALL_REAL (free, freeme);

          END_MALLOC_PROTECT ();

        }

    }

  else

    {

      /* back pointer up a bit to the beginning of crumple zone */

      char *base = (char *)buf;

      base -= __mf_opts.crumple_zone;

      if (__mf_opts.trace_mf_calls)

        {

          VERBOSE_TRACE ("freeing pointer %p = %p - %u\n",

                         (void *) base,

                         (void *) buf,

                         __mf_opts.crumple_zone);

        }

      BEGIN_MALLOC_PROTECT ();

      CALL_REAL (free, base);

      END_MALLOC_PROTECT ();

    }

}

/* We can only wrap mmap if the target supports it.  Likewise for munmap.

   We assume we have both if we have mmap.  */

#ifdef HAVE_MMAP

#if PIC

/* A special bootstrap variant. */

void *

__mf_0fn_mmap (void *start, size_t l, int prot, int f, int fd, off_t off)

{

#if defined(__FreeBSD__)

  if (f == 0x1000 && fd == -1 && prot == 0 && off == 0)

    return 0;

#endif /* Ignore red zone allocation request for initial thread's stack. */

  return (void *) -1;

}

#endif

#undef mmap

WRAPPER(void *, mmap,

        void  *start,  size_t length, int prot,

        int flags, int fd, off_t offset)

{

  DECLARE(void *, mmap, void *, size_t, int,

                            int, int, off_t);

  void *result;

  BEGIN_PROTECT (mmap, start, length, prot, flags, fd, offset);

  result = CALL_REAL (mmap, start, length, prot,

                        flags, fd, offset);

  /*

  VERBOSE_TRACE ("mmap (%08lx, %08lx, ...) => %08lx\n",

                 (uintptr_t) start, (uintptr_t) length,

                 (uintptr_t) result);

  */

  if (result != (void *)-1)

    {

      /* Register each page as a heap object.  Why not register it all

         as a single segment?  That's so that a later munmap() call

         can unmap individual pages.  XXX: would __MF_TYPE_GUESS make

         this more automatic?  */

      size_t ps = getpagesize ();

      uintptr_t base = (uintptr_t) result;

      uintptr_t offset;

      for (offset=0; offset<length; offset+=ps)

        {

          /* XXX: We could map PROT_NONE to __MF_TYPE_NOACCESS. */

          /* XXX: Unaccessed HEAP pages are reported as leaks.  Is this

             appropriate for unaccessed mmap pages? */

          __mf_register ((void *) CLAMPADD (base, offset), ps,

                         __MF_TYPE_HEAP_I, "mmap page");

        }

    }

  return result;

}

#if PIC

/* A special bootstrap variant. */

int

__mf_0fn_munmap (void *start, size_t length)

{

  return -1;

}

#endif

#undef munmap

WRAPPER(int , munmap, void *start, size_t length)

{

  DECLARE(int, munmap, void *, size_t);

  int result;

  BEGIN_PROTECT (munmap, start, length);

  result = CALL_REAL (munmap, start, length);

  /*

  VERBOSE_TRACE ("munmap (%08lx, %08lx, ...) => %08lx\n",

                 (uintptr_t) start, (uintptr_t) length,

                 (uintptr_t) result);

  */

  if (result == 0)

    {

      /* Unregister each page as a heap object.  */

      size_t ps = getpagesize ();

      uintptr_t base = (uintptr_t) start & (~ (ps - 1)); /* page align */

      uintptr_t offset;

      for (offset=0; offset<length; offset+=ps)

        __mf_unregister ((void *) CLAMPADD (base, offset), ps, __MF_TYPE_HEAP_I);

    }

  return result;

}

#endif /* HAVE_MMAP */

/* This wrapper is a little different, as it's called indirectly from

   __mf_fini also to clean up pending allocations.  */

void *

__mf_wrap_alloca_indirect (size_t c)

{

  DECLARE (void *, malloc, size_t);

  DECLARE (void, free, void *);

  /* This struct, a linked list, tracks alloca'd objects.  The newest

     object is at the head of the list.  If we detect that we've

     popped a few levels of stack, then the listed objects are freed

     as needed.  NB: The tracking struct is allocated with

     real_malloc; the user data with wrap_malloc.

  */

  struct alloca_tracking { void *ptr; void *stack; struct alloca_tracking* next; };

  static struct alloca_tracking *alloca_history = NULL;

  void *stack = __builtin_frame_address (0);

  void *result;

  struct alloca_tracking *track;

  TRACE ("%s\n", __PRETTY_FUNCTION__);

  VERBOSE_TRACE ("alloca stack level %p\n", (void *) stack);

  /* XXX: thread locking! */

  /* Free any previously alloca'd blocks that belong to deeper-nested functions,

     which must therefore have exited by now.  */

#define DEEPER_THAN < /* XXX: for x86; steal find_stack_direction() from libiberty/alloca.c */

  while (alloca_history &&

         ((uintptr_t) alloca_history->stack DEEPER_THAN (uintptr_t) stack))

    {

      struct alloca_tracking *next = alloca_history->next;

      __mf_unregister (alloca_history->ptr, 0, __MF_TYPE_HEAP);

      BEGIN_MALLOC_PROTECT ();

      CALL_REAL (free, alloca_history->ptr);

      CALL_REAL (free, alloca_history);

      END_MALLOC_PROTECT ();

      alloca_history = next;

    }

  /* Allocate new block.  */

  result = NULL;

  if (LIKELY (c > 0)) /* alloca(0) causes no allocation.  */

    {

      BEGIN_MALLOC_PROTECT ();

      track = (struct alloca_tracking *) CALL_REAL (malloc,

                                                    sizeof (struct alloca_tracking));

      END_MALLOC_PROTECT ();

      if (LIKELY (track != NULL))

        {

          BEGIN_MALLOC_PROTECT ();

          result = CALL_REAL (malloc, c);

          END_MALLOC_PROTECT ();

          if (UNLIKELY (result == NULL))

            {

              BEGIN_MALLOC_PROTECT ();

              CALL_REAL (free, track);

              END_MALLOC_PROTECT ();

              /* Too bad.  XXX: What about errno?  */

            }

          else

            {

              __mf_register (result, c, __MF_TYPE_HEAP, "alloca region");

              track->ptr = result;

              track->stack = stack;

              track->next = alloca_history;

              alloca_history = track;

            }

        }

    }

  return result;

}

#undef alloca

WRAPPER(void *, alloca, size_t c)

{

  return __mf_wrap_alloca_indirect (c);

}