diff --git a/ps/parser.c b/ps/parser.c
index 4263a1f..b33f319 100644
--- a/ps/parser.c
+++ b/ps/parser.c
@@ -31,7 +31,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 
-#include "../proc/alloc.h"
+#include "xalloc.h"
 
 #include "common.h"
 #include "c.h"
@@ -184,8 +184,8 @@ static const char *parse_list(const char *arg, const char *(*parse_fn)(char *, s
   const char *err;       /* error code that could or did happen */
   /*** prepare to operate ***/
   node = malloc(sizeof(selection_node));
-  node->u = malloc(strlen(arg)*sizeof(sel_union)); /* waste is insignificant */
   node->n = 0;
+  node->u = NULL;
   buf = strdup(arg);
   /*** sanity check and count items ***/
   need_item = 1; /* true */
@@ -199,12 +199,13 @@ static const char *parse_list(const char *arg, const char *(*parse_fn)(char *, s
       need_item=1;
       break;
     default:
-      if(need_item) items++;
+      if(need_item && items<INT_MAX) items++;
       need_item=0;
     }
   } while (*++walk);
   if(need_item) goto parse_error;
   node->n = items;
+  node->u = xcalloc(items, sizeof(sel_union));
   /*** actually parse the list ***/
   walk = buf;
   while(items--){
@@ -1031,15 +1032,15 @@ static const char *parse_trailing_pids(void){
   thisarg = ps_argc - 1;   /* we must be at the end now */
 
   pidnode = malloc(sizeof(selection_node));
-  pidnode->u = malloc(i*sizeof(sel_union)); /* waste is insignificant */
+  pidnode->u = xcalloc(i, sizeof(sel_union)); /* waste is insignificant */
   pidnode->n = 0;
 
   grpnode = malloc(sizeof(selection_node));
-  grpnode->u = malloc(i*sizeof(sel_union)); /* waste is insignificant */
+  grpnode->u = xcalloc(i, sizeof(sel_union)); /* waste is insignificant */
   grpnode->n = 0;
 
   sidnode = malloc(sizeof(selection_node));
-  sidnode->u = malloc(i*sizeof(sel_union)); /* waste is insignificant */
+  sidnode->u = xcalloc(i, sizeof(sel_union)); /* waste is insignificant */
   sidnode->n = 0;
 
   while(i--){
-- 
2.40.1