kc3-lang/libbsd/src/recallocarray.c

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• Hash : 01f0d1ea
  Author :
  Date : 2020-12-31T12:46:03
  

  Add recallocarray() and freezero() from OpenBSD
  
  Add recallocarray(), introduced in OpenBSD 6.1, and freezero(),
  introduced in OpenBSD 6.2. The former is imported as-is from OpenBSD,
  while the latter is the non-malloc-internal branch of the same code (and
  also the OpenSSH portable variant).
  
  Both of these originated in OpenBSD, but have also been implemented by
  IllumOS, cf. https://www.illumos.org/issues/8546
  
  Documentation for these functions is in malloc(3) upstream, the relevant
  parts of which were previously imported in reallocarray(3bsd). Update
  reallocarray(3bsd) with the changes that were introduced since, and add
  the relevant bits for recallocarray() and freezero(), plus aliases.
  
  [guillem@hadrons.org: Update copyright in COPYING. ]
  
  Closes: !10
  Signed-off-by: Guillem Jover <guillem@hadrons.org>
  

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• src/recallocarray.c

• /*	$OpenBSD: recallocarray.c,v 1.1 2017/03/06 18:44:21 otto Exp $	*/
  /*
   * Copyright (c) 2008, 2017 Otto Moerbeek <otto@drijf.net>
   *
   * Permission to use, copy, modify, and distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
   * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
   * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
   * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
   * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   */
  
  #include <errno.h>
  #include <stdlib.h>
  #include <stdint.h>
  #include <string.h>
  #include <unistd.h>
  
  /*
   * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
   * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
   */
  #define MUL_NO_OVERFLOW ((size_t)1 << (sizeof(size_t) * 4))
  
  void *
  recallocarray(void *ptr, size_t oldnmemb, size_t newnmemb, size_t size)
  {
  	size_t oldsize, newsize;
  	void *newptr;
  
  	if (ptr == NULL)
  		return calloc(newnmemb, size);
  
  	if ((newnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
  	    newnmemb > 0 && SIZE_MAX / newnmemb < size) {
  		errno = ENOMEM;
  		return NULL;
  	}
  	newsize = newnmemb * size;
  
  	if ((oldnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
  	    oldnmemb > 0 && SIZE_MAX / oldnmemb < size) {
  		errno = EINVAL;
  		return NULL;
  	}
  	oldsize = oldnmemb * size;
  
  	/*
  	 * Don't bother too much if we're shrinking just a bit,
  	 * we do not shrink for series of small steps, oh well.
  	 */
  	if (newsize <= oldsize) {
  		size_t d = oldsize - newsize;
  
  		if (d < oldsize / 2 && d < (size_t)getpagesize()) {
  			memset((char *)ptr + newsize, 0, d);
  			return ptr;
  		}
  	}
  
  	newptr = malloc(newsize);
  	if (newptr == NULL)
  		return NULL;
  
  	if (newsize > oldsize) {
  		memcpy(newptr, ptr, oldsize);
  		memset((char *)newptr + oldsize, 0, newsize - oldsize);
  	} else
  		memcpy(newptr, ptr, newsize);
  
  	explicit_bzero(ptr, oldsize);
  	free(ptr);
  
  	return newptr;
  }
  

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