4922 all calloc() implementations should check for overflow

*** 25,44 ****
   */
  
  /*      Copyright (c) 1988 AT&T */
  /*        All Rights Reserved   */
  
- #pragma ident   "%Z%%M% %I%     %E% SMI"
- 
  #include <sys/types.h>
  
  #ifndef debug
  #define NDEBUG
  #endif
  
  #include <stdlib.h>
  #include <string.h>
  #include "assert.h"
  #include "malloc.h"
  #include "mallint.h"
  #include <thread.h>
  #include <pthread.h>
--- 25,43 ----
   */
  
  /*      Copyright (c) 1988 AT&T */
  /*        All Rights Reserved   */
  
  #include <sys/types.h>
  
  #ifndef debug
  #define NDEBUG
  #endif
  
  #include <stdlib.h>
  #include <string.h>
+ #include <errno.h>
  #include "assert.h"
  #include "malloc.h"
  #include "mallint.h"
  #include <thread.h>
  #include <pthread.h>
*** 843,858 ****
  
  void *
  calloc(size_t num, size_t size)
  {
          char *mp;
  
!         num *= size;
!         mp = malloc(num);
          if (mp == NULL)
                  return (NULL);
!         (void) memset(mp, 0, num);
          return (mp);
  }
  
  
  /*
--- 842,869 ----
  
  void *
  calloc(size_t num, size_t size)
  {
          char *mp;
+         size_t total;
+ 
+         if (num == 0 || size == 0) {
+                 total = 0;
+         } else {
+                 total = num * size;
+ 
+                 /* check for overflow */
+                 if ((total / num) != size) {
+                         errno = ENOMEM;
+                         return (NULL);
+                 }
+         }
  
!         mp = malloc(total);
          if (mp == NULL)
                  return (NULL);
!         (void) memset(mp, 0, total);
          return (mp);
  }
  
  
  /*