2099

Committed 09 Apr 2026 07:36PM UTC coverage: 80.342% (-0.6%) from 80.922%

Build # 2099

Build Type

push

travis-ci

Committed by

ivmai

Commit Message

Prevent abort in GC_suspend in case of thread terminated by DllMain

Issue #886 (bdwgc).

A race condition is possible where we read `pending_delete_thread` as
false but the thread terminates before we reach the suspend.  In this
case, there is we should not abort because the thread has terminated
and does not need suspension.  We should be able to recognize this case
by checking the last error code (`SuspendThread()` on a terminated
thread should set an error code of `ERROR_ACCESS_DENIED` or
`ERROR_NO_MORE_ITEMS`).

* win32_threads.c [!MSWINCE] (GC_suspend): Code refactoring to have
`SuspendThread()` call in a single place.
* win32_threads.c [!MSWINCE && !GC_NO_THREADS_DISCOVERY] (GC_suspend):
If `SuspendThread()` failed with `ERROR_ACCESS_DENIED` or
`ERROR_NO_MORE_ITEMS`, then assume the thread has been just terminated
(set `t->pending_delete_thread` and return).

Co-authored-by: Tobiasz Laskowski <tobil4sk@outlook.com>

Coverage Stats

7197 of 8958 relevant lines covered (80.34%)

20016292.6 hits per line

Source File
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89.49

/malloc.c

/*
 * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
 * Copyright (c) 1991-1994 by Xerox Corporation.  All rights reserved.
 * Copyright (c) 1999-2004 Hewlett-Packard Development Company, L.P.
 * Copyright (c) 2008-2025 Ivan Maidanski
 *
 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
 * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
 *
 * Permission is hereby granted to use or copy this program
 * for any purpose, provided the above notices are retained on all copies.
 * Permission to modify the code and to distribute modified code is granted,
 * provided the above notices are retained, and a notice that the code was
 * modified is included with the above copyright notice.
 */

#include "private/gc_priv.h"

#include <string.h>

/* Allocate reclaim list for the kind.  Returns `TRUE` on success. */
STATIC GC_bool
GC_alloc_reclaim_list(struct obj_kind *ok)
{
  struct hblk **result;

  GC_ASSERT(I_HOLD_LOCK());
  result = (struct hblk **)GC_scratch_alloc((MAXOBJGRANULES + 1)
                                            * sizeof(struct hblk *));
  if (UNLIKELY(NULL == result))
    return FALSE;

  BZERO(result, (MAXOBJGRANULES + 1) * sizeof(struct hblk *));
  ok->ok_reclaim_list = result;
  return TRUE;
}

/*
 * Allocate a large block of size `lb_adjusted` bytes with the requested
 * alignment (`align_m1 + 1`).  The block is not cleared.  We assume that
 * the size is nonzero and a multiple of `GC_GRANULE_BYTES`, and that
 * it already includes `EXTRA_BYTES` value.  The `flags` argument should
 * be `IGNORE_OFF_PAGE` or 0.  Calls `GC_allochblk()` to do the actual
 * allocation, but also triggers collection and/or heap expansion
 * as appropriate.  Updates value of `GC_bytes_allocd`; does also other
 * accounting.
 */
STATIC ptr_t
GC_alloc_large(size_t lb_adjusted, int kind, unsigned flags, size_t align_m1)
{
  /*
   * TODO: It is unclear which retries limit is sufficient (value of 3 leads
   * to fail in some 32-bit applications, 10 is a kind of arbitrary value).
   */
#define MAX_ALLOCLARGE_RETRIES 10

  int retry_cnt;
  size_t n_blocks; /*< includes alignment */
  struct hblk *h;
  ptr_t result;

  GC_ASSERT(I_HOLD_LOCK());
  if (UNLIKELY(!GC_is_initialized)) {
    UNLOCK(); /*< just to unset `GC_lock_holder` */
    GC_init();
    LOCK();
  }
  GC_ASSERT(lb_adjusted != 0 && (lb_adjusted & (GC_GRANULE_BYTES - 1)) == 0);
  n_blocks = OBJ_SZ_TO_BLOCKS_CHECKED(SIZET_SAT_ADD(lb_adjusted, align_m1));

  /* Do our share of marking work. */
  if (GC_incremental && !GC_dont_gc) {
    GC_collect_a_little_inner(n_blocks);
  }

  h = GC_allochblk(lb_adjusted, kind, flags, align_m1);
#ifdef USE_MUNMAP
  if (NULL == h && GC_merge_unmapped()) {
    h = GC_allochblk(lb_adjusted, kind, flags, align_m1);
  }
#endif
  for (retry_cnt = 0; NULL == h; retry_cnt++) {
    /*
     * Only a few iterations are expected at most, otherwise something
     * is wrong in one of the functions called below.
     */
    if (retry_cnt > MAX_ALLOCLARGE_RETRIES)
      ABORT("Too many retries in GC_alloc_large");
    if (UNLIKELY(!GC_collect_or_expand(n_blocks, flags, retry_cnt > 0)))
      return NULL;
    h = GC_allochblk(lb_adjusted, kind, flags, align_m1);
  }

  GC_bytes_allocd += lb_adjusted;
  if (lb_adjusted > HBLKSIZE) {
    GC_large_allocd_bytes += HBLKSIZE * OBJ_SZ_TO_BLOCKS(lb_adjusted);
    if (GC_large_allocd_bytes > GC_max_large_allocd_bytes)
      GC_max_large_allocd_bytes = GC_large_allocd_bytes;
  }
  /* FIXME: Do we need some way to reset `GC_max_large_allocd_bytes`? */
  result = h->hb_body;
  GC_ASSERT((ADDR(result) & align_m1) == 0);
  return result;
}

/*
 * Allocate a large block of given size in bytes, clear it if appropriate.
 * We assume that the size is nonzero and a multiple of `GC_GRANULE_BYTES`,
 * and that it already includes `EXTRA_BYTES` value.  Update value of
 * `GC_bytes_allocd`.
 */
STATIC ptr_t
GC_alloc_large_and_clear(size_t lb_adjusted, int kind, unsigned flags)
{
  ptr_t result;

  GC_ASSERT(I_HOLD_LOCK());
  result = GC_alloc_large(lb_adjusted, kind, flags, 0 /* `align_m1` */);
  if (LIKELY(result != NULL)
      && (GC_debugging_started || GC_obj_kinds[kind].ok_init)) {
    /* Clear the whole block, in case of `GC_realloc` call. */
    BZERO(result, HBLKSIZE * OBJ_SZ_TO_BLOCKS(lb_adjusted));
  }
  return result;
}

/*
 * Fill in additional entries in `GC_size_map`, including the `i`-th one.
 * Note that a filled in section of the array ending at `n` always has
 * the length of at least `n / 4`.
 */
STATIC void
GC_extend_size_map(size_t i)
{
  size_t original_lg = ALLOC_REQUEST_GRANS(i);
  size_t lg;
  /*
   * The size we try to preserve.  Close to `i`, unless this would
   * introduce too many distinct sizes.
   */
  size_t byte_sz = GRANULES_TO_BYTES(original_lg);
  size_t smaller_than_i = byte_sz - (byte_sz >> 3);
  /* The lowest indexed entry we initialize. */
  size_t low_limit;
  size_t number_of_objs;

  GC_ASSERT(I_HOLD_LOCK());
  GC_ASSERT(0 == GC_size_map[i]);
  if (0 == GC_size_map[smaller_than_i]) {
    low_limit = byte_sz - (byte_sz >> 2); /*< much smaller than `i` */
    lg = original_lg;
    while (GC_size_map[low_limit] != 0)
      low_limit++;
  } else {
    low_limit = smaller_than_i + 1;
    while (GC_size_map[low_limit] != 0)
      low_limit++;

    lg = ALLOC_REQUEST_GRANS(low_limit);
    lg += lg >> 3;
    if (lg < original_lg)
      lg = original_lg;
  }

  /*
   * For these larger sizes, we use an even number of granules.
   * This makes it easier to, e.g., construct a 16-byte-aligned
   * allocator even if `GC_GRANULE_BYTES` is 8.
   */
  lg = (lg + 1) & ~(size_t)1;
  if (lg > MAXOBJGRANULES)
    lg = MAXOBJGRANULES;

  /* If we can fit the same number of larger objects in a block, do so. */
  GC_ASSERT(lg != 0);
  number_of_objs = HBLK_GRANULES / lg;
  GC_ASSERT(number_of_objs != 0);
  lg = (HBLK_GRANULES / number_of_objs) & ~(size_t)1;

  /*
   * We may need one extra byte; do not always fill in
   * `GC_size_map[byte_sz]`.
   */
  byte_sz = GRANULES_TO_BYTES(lg) - EXTRA_BYTES;

  for (; low_limit <= byte_sz; low_limit++)
    GC_size_map[low_limit] = lg;
}

STATIC void *
GC_generic_malloc_inner_small(size_t lb, int kind)
{
  struct obj_kind *ok = &GC_obj_kinds[kind];
  size_t lg = GC_size_map[lb];
  void **opp = &ok->ok_freelist[lg];
  void *op = *opp;

  GC_ASSERT(I_HOLD_LOCK());
  if (UNLIKELY(NULL == op)) {
    if (0 == lg) {
      if (UNLIKELY(!GC_is_initialized)) {
        UNLOCK(); /*< just to unset `GC_lock_holder` */
        GC_init();
        LOCK();
        lg = GC_size_map[lb];
      }
      if (0 == lg) {
        GC_extend_size_map(lb);
        lg = GC_size_map[lb];
        GC_ASSERT(lg != 0);
      }
      /* Retry. */
      opp = &ok->ok_freelist[lg];
      op = *opp;
    }
    if (NULL == op) {
      if (NULL == ok->ok_reclaim_list && !GC_alloc_reclaim_list(ok))
        return NULL;
      op = GC_allocobj(lg, kind);
      if (NULL == op)
        return NULL;
    }
  }
  *opp = obj_link(op);
  obj_link(op) = NULL;
  GC_bytes_allocd += GRANULES_TO_BYTES((word)lg);
  return op;
}

GC_INNER void *
GC_generic_malloc_inner(size_t lb, int kind, unsigned flags)
{
  size_t lb_adjusted;

  GC_ASSERT(I_HOLD_LOCK());
  GC_ASSERT(kind < MAXOBJKINDS);
  if (SMALL_OBJ(lb)) {
    return GC_generic_malloc_inner_small(lb, kind);
  }

#if MAX_EXTRA_BYTES > 0
  if ((flags & IGNORE_OFF_PAGE) != 0 && lb >= HBLKSIZE) {
    /* No need to add `EXTRA_BYTES`. */
    lb_adjusted = lb;
  } else
#endif
  /* else */ {
    lb_adjusted = ADD_EXTRA_BYTES(lb);
  }
  return GC_alloc_large_and_clear(ROUNDUP_GRANULE_SIZE(lb_adjusted), kind,
                                  flags);
}

#ifdef GC_COLLECT_AT_MALLOC
size_t GC_dbg_collect_at_malloc_min_lb = (GC_COLLECT_AT_MALLOC);
#endif

GC_INNER void *
GC_generic_malloc_aligned(size_t lb, int kind, unsigned flags, size_t align_m1)
{
  void *result;

  GC_ASSERT(kind < MAXOBJKINDS);
  if (UNLIKELY(get_have_errors()))
    GC_print_all_errors();
  GC_notify_or_invoke_finalizers();
  GC_DBG_COLLECT_AT_MALLOC(lb);
  if (SMALL_OBJ(lb) && LIKELY(align_m1 < GC_GRANULE_BYTES)) {
    LOCK();
    result = GC_generic_malloc_inner_small(lb, kind);
    UNLOCK();
  } else {
    size_t lg;
    size_t lb_adjusted;
    GC_bool init;

#if MAX_EXTRA_BYTES > 0
    if ((flags & IGNORE_OFF_PAGE) != 0 && lb >= HBLKSIZE) {
      /* No need to add `EXTRA_BYTES`. */
      lb_adjusted = ROUNDUP_GRANULE_SIZE(lb);
#  ifdef THREADS
      lg = BYTES_TO_GRANULES(lb_adjusted);
#  endif
    } else
#endif
    /* else */ {
      if (UNLIKELY(0 == lb))
        lb = 1;
      lg = ALLOC_REQUEST_GRANS(lb);
      lb_adjusted = GRANULES_TO_BYTES(lg);
    }

    init = GC_obj_kinds[kind].ok_init;
    if (LIKELY(align_m1 < GC_GRANULE_BYTES)) {
      align_m1 = 0;
    } else if (align_m1 < HBLKSIZE) {
      align_m1 = HBLKSIZE - 1;
    }
    LOCK();
    result = GC_alloc_large(lb_adjusted, kind, flags, align_m1);
    if (LIKELY(result != NULL)) {
      if (GC_debugging_started
#ifndef THREADS
          || init
#endif
      ) {
        BZERO(result, HBLKSIZE * OBJ_SZ_TO_BLOCKS(lb_adjusted));
      } else {
#ifdef THREADS
        GC_ASSERT(GRANULES_TO_PTRS(lg) >= 2);
        /*
         * Clear any memory that might be used for the GC descriptors
         * before we release the allocator lock.
         */
        ((ptr_t *)result)[0] = NULL;
        ((ptr_t *)result)[1] = NULL;
        ((ptr_t *)result)[GRANULES_TO_PTRS(lg) - 1] = NULL;
        ((ptr_t *)result)[GRANULES_TO_PTRS(lg) - 2] = NULL;
#endif
      }
    }
    UNLOCK();
#ifdef THREADS
    if (init && !GC_debugging_started && result != NULL) {
      /* Clear the rest (i.e. excluding the initial 2 words). */
      BZERO((ptr_t *)result + 2,
            HBLKSIZE * OBJ_SZ_TO_BLOCKS(lb_adjusted) - 2 * sizeof(ptr_t));
    }
#endif
  }
  if (UNLIKELY(NULL == result)) {
    result = (*GC_get_oom_fn())(lb);
    /* Note: result might be misaligned. */
  }
  return result;
}

GC_API GC_ATTR_MALLOC void *GC_CALL
GC_generic_malloc(size_t lb, int kind)
{
  return GC_generic_malloc_aligned(lb, kind, 0 /* `flags` */,
                                   0 /* `align_m1` */);
}

GC_API GC_ATTR_MALLOC void *GC_CALL
GC_malloc_kind_global(size_t lb, int kind)
{
  return GC_malloc_kind_aligned_global(lb, kind, 0 /* `align_m1` */);
}

GC_INNER void *
GC_malloc_kind_aligned_global(size_t lb, int kind, size_t align_m1)
{
  GC_ASSERT(kind < MAXOBJKINDS);
  if (SMALL_OBJ(lb) && LIKELY(align_m1 < HBLKSIZE / 2)) {
    void *op;
    void **opp;
    size_t lg;

    GC_DBG_COLLECT_AT_MALLOC(lb);
    LOCK();
    lg = GC_size_map[lb];
    opp = &GC_obj_kinds[kind].ok_freelist[lg];
    op = *opp;
    if (UNLIKELY(align_m1 >= GC_GRANULE_BYTES)) {
      /* TODO: Avoid linear search. */
      for (; (ADDR(op) & align_m1) != 0; op = *opp) {
        opp = &obj_link(op);
      }
    }
    if (LIKELY(op != NULL)) {
      GC_ASSERT(PTRFREE == kind || NULL == obj_link(op)
                || (ADDR(obj_link(op)) < GC_greatest_real_heap_addr
                    && GC_least_real_heap_addr < ADDR(obj_link(op))));
      *opp = obj_link(op);
      if (kind != PTRFREE)
        obj_link(op) = NULL;
      GC_bytes_allocd += GRANULES_TO_BYTES((word)lg);
      UNLOCK();
      GC_ASSERT((ADDR(op) & align_m1) == 0);
      return op;
    }
    UNLOCK();
  }

  /*
   * We make the `GC_clear_stack()` call a tail one, hoping to get more
   * of the stack.
   */
  return GC_clear_stack(
      GC_generic_malloc_aligned(lb, kind, 0 /* `flags` */, align_m1));
}

#if defined(THREADS) && !defined(THREAD_LOCAL_ALLOC)
GC_API GC_ATTR_MALLOC void *GC_CALL
GC_malloc_kind(size_t lb, int kind)
{
  return GC_malloc_kind_global(lb, kind);
}
#endif

GC_API GC_ATTR_MALLOC void *GC_CALL
GC_malloc_atomic(size_t lb)
{
  /* Allocate `lb` bytes of atomic (pointer-free) data. */
  return GC_malloc_kind(lb, PTRFREE);
}

GC_API GC_ATTR_MALLOC void *GC_CALL
GC_malloc(size_t lb)
{
  /* Allocate `lb` bytes of composite (pointer-containing) data. */
  return GC_malloc_kind(lb, NORMAL);
}

GC_API GC_ATTR_MALLOC void *GC_CALL
GC_generic_malloc_uncollectable(size_t lb, int kind)
{
  void *op;
  size_t lb_orig = lb;

  GC_ASSERT(kind < MAXOBJKINDS);
  if (EXTRA_BYTES != 0 && LIKELY(lb != 0)) {
    /*
     * We do not need the extra byte, since this will not be collected
     * anyway.
     */
    lb--;
  }

  if (SMALL_OBJ(lb)) {
    void **opp;
    size_t lg;

    if (UNLIKELY(get_have_errors()))
      GC_print_all_errors();
    GC_notify_or_invoke_finalizers();
    GC_DBG_COLLECT_AT_MALLOC(lb_orig);
    LOCK();
    lg = GC_size_map[lb];
    opp = &GC_obj_kinds[kind].ok_freelist[lg];
    op = *opp;
    if (LIKELY(op != NULL)) {
      *opp = obj_link(op);
      obj_link(op) = NULL;
      GC_bytes_allocd += GRANULES_TO_BYTES((word)lg);
      /*
       * Mark bit was already set on free list.  It will be cleared only
       * temporarily during a collection, as a result of the normal
       * free-list mark bit clearing.
       */
      GC_non_gc_bytes += GRANULES_TO_BYTES((word)lg);
    } else {
      op = GC_generic_malloc_inner_small(lb, kind);
      if (NULL == op) {
        GC_oom_func oom_fn = GC_oom_fn;
        UNLOCK();
        return (*oom_fn)(lb_orig);
      }
      /* For small objects, the free lists are completely marked. */
    }
    GC_ASSERT(GC_is_marked(op));
    UNLOCK();
  } else {
    op = GC_generic_malloc_aligned(lb, kind, 0 /* `flags` */,
                                   0 /* `align_m1` */);
    if (op != NULL) {
      hdr *hhdr;

      GC_ASSERT(HBLKDISPL(op) == 0); /*< large block */
      LOCK();
      hhdr = HDR(op);
      set_mark_bit_from_hdr(hhdr, 0); /*< the only object */
#ifndef THREADS
      /*
       * This is not guaranteed in the multi-threaded case because the
       * counter could be updated before locking.
       */
      GC_ASSERT(0 == hhdr->hb_n_marks);
#endif
      hhdr->hb_n_marks = 1;
      UNLOCK();
    }
  }
  return op;
}

GC_API GC_ATTR_MALLOC void *GC_CALL
GC_malloc_uncollectable(size_t lb)
{
  /*
   * Allocate `lb` bytes of pointer-containing, traced, but not collectible
   * data.
   */
  return GC_generic_malloc_uncollectable(lb, UNCOLLECTABLE);
}

#ifdef GC_ATOMIC_UNCOLLECTABLE
GC_API GC_ATTR_MALLOC void *GC_CALL
GC_malloc_atomic_uncollectable(size_t lb)
{
  return GC_generic_malloc_uncollectable(lb, AUNCOLLECTABLE);
}
#endif /* GC_ATOMIC_UNCOLLECTABLE */

#if defined(REDIRECT_MALLOC) && !defined(REDIRECT_MALLOC_IN_HEADER)

#  ifndef MSWINCE
#    include <errno.h>
#  endif

#  ifdef REDIRECT_MALLOC_DEBUG
#    include "private/dbg_mlc.h"
#    ifndef REDIRECT_MALLOC_UNCOLLECTABLE
#      define REDIRECT_MALLOC_F(lb) \
        GC_debug_malloc_inner(lb, TRUE /* `is_redirect` */, GC_DBG_EXTRAS)
#    else
#      define REDIRECT_MALLOC_F(lb) \
        GC_debug_malloc_uncollectable_inner(lb, TRUE, GC_DBG_EXTRAS)
#    endif
#  elif defined(REDIRECT_MALLOC_UNCOLLECTABLE)
#    define REDIRECT_MALLOC_F GC_malloc_uncollectable
#  else
#    define REDIRECT_MALLOC_F GC_malloc
#  endif

GC_API void *
malloc(size_t lb)
{
  /*
   * It might help to manually inline the `GC_malloc` call here.
   * But any decent compiler should reduce the extra procedure call
   * to at most a jump instruction in this case.
   */
  return REDIRECT_MALLOC_F(lb);
}

#  if defined(REDIR_MALLOC_AND_LINUX_THREADS)                    \
      && (defined(IGNORE_FREE) || defined(REDIRECT_MALLOC_DEBUG) \
          || !defined(REDIRECT_MALLOC_UNCOLLECTABLE))
#    ifdef HAVE_LIBPTHREAD_SO
STATIC ptr_t GC_libpthread_start = NULL;
STATIC ptr_t GC_libpthread_end = NULL;
#    endif
STATIC ptr_t GC_libld_start = NULL;
STATIC ptr_t GC_libld_end = NULL;
static GC_bool lib_bounds_set = FALSE;

GC_INNER void
GC_init_lib_bounds(void)
{
  IF_CANCEL(int cancel_state;)

  /*
   * This test does not need to ensure memory visibility, since the bounds
   * will be set when/if we create another thread.
   */
  if (LIKELY(lib_bounds_set))
    return;

  DISABLE_CANCEL(cancel_state);
  GC_init(); /*< if not called yet */

#    if defined(GC_ASSERTIONS) && defined(GC_ALWAYS_MULTITHREADED)
  LOCK(); /*< just to set `GC_lock_holder` */
#    endif
#    ifdef HAVE_LIBPTHREAD_SO
  if (!GC_text_mapping("libpthread-", &GC_libpthread_start,
                       &GC_libpthread_end)) {
    WARN("Failed to find libpthread.so text mapping: Expect crash\n", 0);
    /*
     * This might still work with some versions of `libpthread`,
     * so we do not `abort`.
     */
  }
#    endif
  if (!GC_text_mapping("ld-", &GC_libld_start, &GC_libld_end)) {
    WARN("Failed to find ld.so text mapping: Expect crash\n", 0);
  }
#    if defined(GC_ASSERTIONS) && defined(GC_ALWAYS_MULTITHREADED)
  UNLOCK();
#    endif
  RESTORE_CANCEL(cancel_state);
  lib_bounds_set = TRUE;
}
#  endif

GC_API void *
calloc(size_t n, size_t lb)
{
  if (UNLIKELY((lb | n) > GC_SQRT_SIZE_MAX) /*< fast initial test */
      && lb && n > GC_SIZE_MAX / lb)
    return (*GC_get_oom_fn())(GC_SIZE_MAX); /*< `n * lb` overflow */
#  ifdef REDIR_MALLOC_AND_LINUX_THREADS
#    if defined(REDIRECT_MALLOC_DEBUG) \
        || !defined(REDIRECT_MALLOC_UNCOLLECTABLE)
  /*
   * The linker may allocate some memory that is only pointed to by
   * memory-mapped thread stacks.  Make sure it is not collectible.
   */
  {
    ptr_t caller = (ptr_t)__builtin_return_address(0);

    GC_init_lib_bounds();
    if (ADDR_INSIDE(caller, GC_libld_start, GC_libld_end)
#      ifdef HAVE_LIBPTHREAD_SO
        /*
         * Note: the two ranges are actually usually adjacent, so there
         * may be a way to speed this up.
         */
        || ADDR_INSIDE(caller, GC_libpthread_start, GC_libpthread_end)
#      endif
    ) {
      return GC_generic_malloc_uncollectable(n * lb, UNCOLLECTABLE);
    }
  }
#    elif defined(IGNORE_FREE)
  /* Just to ensure `static` variables used by `free()` are initialized. */
  GC_init_lib_bounds();
#    endif
#  endif
  return REDIRECT_MALLOC_F(n * lb);
}

#  ifndef strdup
GC_API char *
strdup(const char *s)
{
  size_t lb = strlen(s) + 1;
  char *result = (char *)REDIRECT_MALLOC_F(lb);

  if (UNLIKELY(NULL == result)) {
#    ifndef MSWINCE
    errno = ENOMEM;
#    endif
    return NULL;
  }
  BCOPY(s, result, lb);
  return result;
}
#  else
/*
 * If `strdup` is macro defined, we assume that it actually calls `malloc`,
 * and thus the right thing will happen even without overriding it.
 * This seems to be true on most Linux systems.
 */
#  endif /* strdup */

#  ifndef strndup
/* This is similar to `strdup()`. */
GC_API char *
strndup(const char *str, size_t size)
{
  char *copy;
  size_t len = strlen(str);
  if (UNLIKELY(len > size))
    len = size;
  copy = (char *)REDIRECT_MALLOC_F(len + 1);
  if (UNLIKELY(NULL == copy)) {
#    ifndef MSWINCE
    errno = ENOMEM;
#    endif
    return NULL;
  }
  if (LIKELY(len > 0))
    BCOPY(str, copy, len);
  copy[len] = '\0';
  return copy;
}
#  endif /* !strndup */

#  ifdef REDIRECT_MALLOC_DEBUG
#    define REDIRECT_FREE_F GC_debug_free
#    define REDIRECT_FREEZERO_F GC_debug_freezero
#  else
#    define REDIRECT_FREE_F GC_free
#    define REDIRECT_FREEZERO_F GC_freezero
#  endif

GC_API void
free(void *p)
{
#  if defined(REDIR_MALLOC_AND_LINUX_THREADS) \
      && !defined(USE_PROC_FOR_LIBRARIES)     \
      && (defined(REDIRECT_MALLOC_DEBUG) || defined(IGNORE_FREE))
  /*
   * Do not bother with initialization checks.  If nothing has been
   * initialized, then the check fails, and that is safe, since we have
   * not allocated uncollectible objects neither.
   */
  ptr_t caller = (ptr_t)__builtin_return_address(0);

  /*
   * This test does not need to ensure memory visibility, since the bounds
   * will be set when/if we create another thread.
   */
  if (ADDR_INSIDE(caller, GC_libld_start, GC_libld_end)
#    ifdef HAVE_LIBPTHREAD_SO
      || ADDR_INSIDE(caller, GC_libpthread_start, GC_libpthread_end)
#    endif
  ) {
    GC_free(p);
    return;
  }
#  endif
#  ifdef IGNORE_FREE
  UNUSED_ARG(p);
#  else
  REDIRECT_FREE_F(p);
#  endif
}

EXTERN_C_BEGIN
GC_API void free_sized(void *p, size_t lb);
GC_API void freezero(void *p, size_t clear_lb);
GC_API void freezeroall(void *p);
EXTERN_C_END

GC_API void
free_sized(void *p, size_t lb)
{
  UNUSED_ARG(lb);
  free(p);
}

GC_API void
freezero(void *p, size_t clear_lb)
{
  /* We do not expect the caller is in `libdl` or `libpthread`. */
#  ifdef IGNORE_FREE
  if (UNLIKELY(NULL == p) || UNLIKELY(0 == clear_lb))
    return;

  LOCK();
  {
    size_t lb;
#    ifdef REDIRECT_MALLOC_DEBUG
    ptr_t base = (ptr_t)GC_base(p);

    GC_ASSERT(base != NULL);
    lb = HDR(p)->hb_sz - (size_t)((ptr_t)p - base); /*< `sizeof(oh)` */
#    else
    GC_ASSERT(GC_base(p) == p);
    lb = HDR(p)->hb_sz;
#    endif
    if (LIKELY(clear_lb > lb))
      clear_lb = lb;
  }
  /* Skip deallocation but clear the object. */
  UNLOCK();
  BZERO(p, clear_lb);
#  else
  REDIRECT_FREEZERO_F(p, clear_lb);
#  endif
}

GC_API void
freezeroall(void *p)
{
  freezero(p, GC_SIZE_MAX);
}

#endif /* REDIRECT_MALLOC && !REDIRECT_MALLOC_IN_HEADER */

GC_INNER void
GC_free_internal(void *base, const hdr *hhdr, size_t clear_ofs,
                 size_t clear_lb)
{
  size_t lb = hhdr->hb_sz;           /*< size in bytes */
  size_t lg = BYTES_TO_GRANULES(lb); /*< size in granules */
  int kind = hhdr->hb_obj_kind;

  GC_ASSERT(I_HOLD_LOCK());
#ifdef LOG_ALLOCS
  GC_log_printf("Free %p after GC #%lu\n", base, (unsigned long)GC_gc_no);
#endif
  GC_bytes_freed += lb;
  if (IS_UNCOLLECTABLE(kind))
    GC_non_gc_bytes -= lb;

  /*
   * Ensure the part of object to clear does not overrun the object.
   * Note: `SIZET_SAT_ADD(clear_ofs, clear_lb) > lb` cannot be used instead as
   * otherwise "memset specified bound exceeds maximum object size" warning
   * (a false positive) is reported by gcc-13.
   */
  if (UNLIKELY(clear_ofs >= GC_SIZE_MAX - clear_lb)
      || UNLIKELY(clear_ofs + clear_lb > lb))
    clear_lb = lb > clear_ofs ? lb - clear_ofs : 0;

  if (LIKELY(lg <= MAXOBJGRANULES)) {
    struct obj_kind *ok = &GC_obj_kinds[kind];
    void **flh;

    if (ok->ok_init && LIKELY(lb > sizeof(ptr_t))) {
      clear_ofs = sizeof(ptr_t);
      clear_lb = lb - sizeof(ptr_t);
    }
    if (clear_lb > 0)
      BZERO((ptr_t)base + clear_ofs, clear_lb);

    /*
     * It is unnecessary to clear the mark bit.  If the object is reallocated,
     * it does not matter.  Otherwise, the collector will do it, since it is
     * on a free list.
     */

    flh = &ok->ok_freelist[lg];
    obj_link(base) = *flh;
    *flh = (ptr_t)base;
  } else {
    if (clear_lb > 0)
      BZERO((ptr_t)base + clear_ofs, clear_lb);
    if (lb > HBLKSIZE) {
      GC_large_allocd_bytes -= HBLKSIZE * OBJ_SZ_TO_BLOCKS(lb);
    }
    GC_ASSERT(ADDR(HBLKPTR(base)) == ADDR(hhdr->hb_block));
    GC_freehblk(hhdr->hb_block);
  }
  FREE_PROFILER_HOOK(base);
}

GC_API void GC_CALL
GC_free(void *p)
{
  const hdr *hhdr;

  if (UNLIKELY(NULL == p)) {
    /* Required by ANSI. */
    return;
  }

  LOCK();
  hhdr = HDR(p);
#if defined(REDIRECT_MALLOC)                                           \
    && ((defined(NEED_CALLINFO) && defined(GC_HAVE_BUILTIN_BACKTRACE)) \
        || defined(REDIR_MALLOC_AND_LINUX_THREADS) || defined(MSWIN32))
  /*
   * This might be called indirectly by `GC_print_callers` to free the
   * result of `backtrace_symbols()`.  For the other cases, this seems
   * to happen implicitly.  Do not try to deallocate that memory.
   */
  if (UNLIKELY(NULL == hhdr)) {
    UNLOCK();
    return;
  }
#endif
  GC_ASSERT(GC_base(p) == p);
  GC_free_internal(p, hhdr, 0 /* `clear_ofs` */, 0 /* `clear_lb` */);
  UNLOCK();
}

GC_API void GC_CALL
GC_freezero(void *p, size_t clear_lb)
{
  if (UNLIKELY(NULL == p))
    return;

  LOCK();
  GC_ASSERT(GC_base(p) == p);
  GC_free_internal(p, HDR(p), 0 /* `clear_ofs` */, clear_lb);
  UNLOCK();
}

bdwgc / bdwgc / 2099

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