IABSD.fr/src/bin/ksh/alloc.c

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• Author : jca
  Date : 2018-01-16 22:52:32
  Hash : 6c72b531
  Message : Introduce internal_warningf() and mark internal_errorf() as noreturn This helps tools like scan-build, and follows the example of warningf() and errorf(). ok anton@

• bin/ksh/alloc.c

• /*	$OpenBSD: alloc.c,v 1.19 2018/01/16 22:52:32 jca Exp $	*/
  
  /* Public domain, like most of the rest of ksh */
  
  /*
   * area-based allocation built on malloc/free
   */
  
  #include <stdint.h>
  #include <stdlib.h>
  
  #include "sh.h"
  
  struct link {
  	struct link *prev;
  	struct link *next;
  };
  
  Area *
  ainit(Area *ap)
  {
  	ap->freelist = NULL;
  	return ap;
  }
  
  void
  afreeall(Area *ap)
  {
  	struct link *l, *l2;
  
  	for (l = ap->freelist; l != NULL; l = l2) {
  		l2 = l->next;
  		free(l);
  	}
  	ap->freelist = NULL;
  }
  
  #define L2P(l)	( (void *)(((char *)(l)) + sizeof(struct link)) )
  #define P2L(p)	( (struct link *)(((char *)(p)) - sizeof(struct link)) )
  
  void *
  alloc(size_t size, Area *ap)
  {
  	struct link *l;
  
  	/* ensure that we don't overflow by allocating space for link */
  	if (size > SIZE_MAX - sizeof(struct link))
  		internal_errorf("unable to allocate memory");
  
  	l = malloc(sizeof(struct link) + size);
  	if (l == NULL)
  		internal_errorf("unable to allocate memory");
  	l->next = ap->freelist;
  	l->prev = NULL;
  	if (ap->freelist)
  		ap->freelist->prev = l;
  	ap->freelist = l;
  
  	return L2P(l);
  }
  
  /*
   * Copied from calloc().
   *
   * 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	(1UL << (sizeof(size_t) * 4))
  
  void *
  areallocarray(void *ptr, size_t nmemb, size_t size, Area *ap)
  {
  	/* condition logic cloned from calloc() */
  	if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
  	    nmemb > 0 && SIZE_MAX / nmemb < size) {
  		internal_errorf("unable to allocate memory");
  	}
  
  	return aresize(ptr, nmemb * size, ap);
  }
  
  void *
  aresize(void *ptr, size_t size, Area *ap)
  {
  	struct link *l, *l2, *lprev, *lnext;
  
  	if (ptr == NULL)
  		return alloc(size, ap);
  
  	/* ensure that we don't overflow by allocating space for link */
  	if (size > SIZE_MAX - sizeof(struct link))
  		internal_errorf("unable to allocate memory");
  
  	l = P2L(ptr);
  	lprev = l->prev;
  	lnext = l->next;
  
  	l2 = realloc(l, sizeof(struct link) + size);
  	if (l2 == NULL)
  		internal_errorf("unable to allocate memory");
  	if (lprev)
  		lprev->next = l2;
  	else
  		ap->freelist = l2;
  	if (lnext)
  		lnext->prev = l2;
  
  	return L2P(l2);
  }
  
  void
  afree(void *ptr, Area *ap)
  {
  	struct link *l;
  
  	if (!ptr)
  		return;
  
  	l = P2L(ptr);
  	if (l->prev)
  		l->prev->next = l->next;
  	else
  		ap->freelist = l->next;
  	if (l->next)
  		l->next->prev = l->prev;
  
  	free(l);
  }