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hardened_malloc
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avoid redundant checks for large realloc

pull/50/head
Daniel Micay 2018-10-06 13:31:16 -04:00
parent eb7ced7781
commit d18b05eaf4
1 changed files with 41 additions and 41 deletions
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82
malloc.c
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@ -847,28 +847,28 @@ EXPORT void *h_realloc(void *old, size_t size) {
size_t old_rounded_size = PAGE_CEILING(old_size); size_t old_rounded_size = PAGE_CEILING(old_size);
size_t rounded_size = PAGE_CEILING(size); size_t rounded_size = PAGE_CEILING(size);
// in-place shrink if (size > max_slab_size_class) {
if (size < old_size && size > max_slab_size_class) { // in-place shrink
void *new_end = (char *)old + rounded_size; if (size < old_size) {
if (memory_map_fixed(new_end, old_guard_size)) { void *new_end = (char *)old + rounded_size;
return NULL; if (memory_map_fixed(new_end, old_guard_size)) {
return NULL;
}
void *new_guard_end = (char *)new_end + old_guard_size;
memory_unmap(new_guard_end, old_rounded_size - rounded_size);
mutex_lock(&regions_lock);
struct region_info *region = regions_find(old);
if (region == NULL) {
fatal_error("invalid realloc");
}
region->size = size;
mutex_unlock(&regions_lock);
return old;
} }
void *new_guard_end = (char *)new_end + old_guard_size;
memory_unmap(new_guard_end, old_rounded_size - rounded_size);
mutex_lock(&regions_lock); // in-place growth
struct region_info *region = regions_find(old);
if (region == NULL) {
fatal_error("invalid realloc");
}
region->size = size;
mutex_unlock(&regions_lock);
return old;
}
// in-place growth
if (size > old_size) {
void *guard_end = (char *)old + old_rounded_size + old_guard_size; void *guard_end = (char *)old + old_rounded_size + old_guard_size;
size_t extra = rounded_size - old_rounded_size; size_t extra = rounded_size - old_rounded_size;
if (!memory_remap((char *)old + old_rounded_size, old_guard_size, old_guard_size + extra)) { if (!memory_remap((char *)old + old_rounded_size, old_guard_size, old_guard_size + extra)) {
@ -886,31 +886,31 @@ EXPORT void *h_realloc(void *old, size_t size) {
return old; return old;
} }
} }
}
size_t copy_size = size < old_size ? size : old_size; size_t copy_size = size < old_size ? size : old_size;
if (copy_size >= mremap_threshold) { if (copy_size >= mremap_threshold) {
void *new = allocate(size); void *new = allocate(size);
if (new == NULL) { if (new == NULL) {
return NULL; return NULL;
} }
mutex_lock(&regions_lock); mutex_lock(&regions_lock);
struct region_info *region = regions_find(old); struct region_info *region = regions_find(old);
if (region == NULL) { if (region == NULL) {
fatal_error("invalid realloc"); fatal_error("invalid realloc");
} }
regions_delete(region); regions_delete(region);
mutex_unlock(&regions_lock); mutex_unlock(&regions_lock);
if (memory_remap_fixed(old, old_size, new, size)) { if (memory_remap_fixed(old, old_size, new, size)) {
memcpy(new, old, copy_size); memcpy(new, old, copy_size);
deallocate_pages(old, old_size, old_guard_size); deallocate_pages(old, old_size, old_guard_size);
} else { } else {
memory_unmap((char *)old - old_guard_size, old_guard_size); memory_unmap((char *)old - old_guard_size, old_guard_size);
memory_unmap((char *)old + PAGE_CEILING(old_size), old_guard_size); memory_unmap((char *)old + PAGE_CEILING(old_size), old_guard_size);
}
return new;
} }
return new;
} }
} }