Index: pstree.c
--- pstree.c.orig
+++ pstree.c
@@ -75,7 +75,7 @@ extern getargs(struct ProcInfo *, int, char *, int);
  * DragonFlyBSD contributed by Krzysztof Piecuch <piecuch AT kpiecuch.pl>                                                                    
  */
 #  define HAS_PGID
-#  define PSCMD 	"ps -axwwo user,pid,ppid,pgid,command"
+#  define PSCMD 	"ps -kaxwwo user,pid,ppid,pgid,command"
 #  define PSFORMAT 	"%s %ld %ld %ld %[^\n]"
 #  define PSVARS	P[i].name, &P[i].pid, &P[i].ppid, &P[i].pgid, P[i].cmd
 #  define PSVARSN	5
@@ -899,6 +899,11 @@ int main(int argc, char **argv) {
   FixParentCycle();                                                                                                                          
 #endif                                                                                                                                       
   
+  if (pledge("stdio getpw proc tty", NULL) == -1) {
+    fprintf(stderr, "%s: pledge\n", Progname);
+    exit(1);
+  }
+
   if (NProc == 0) {
     fprintf(stderr, "%s: No processes read.\n", Progname);
     exit(1);