test for failure of open prior before ftruncate.

CID 978588

Index: history.c
===================================================================
RCS file: /cvsroot/src/bin/ksh/history.c,v
retrieving revision 1.11
diff -u -p -u -r1.11 history.c
--- history.c	31 Aug 2011 16:24:54 -0000	1.11
+++ history.c	14 Jan 2017 18:22:31 -0000
@@ -757,13 +757,14 @@ hist_finish()
   else
     hp = histlist;
 
-  fd = open(hname, O_WRONLY | O_CREAT | O_TRUNC | O_EXLOCK, 0777);
-  /* Remove anything written before we got the lock */
-  ftruncate(fd, 0);
-  if (fd >= 0 && (fh = fdopen(fd, "w"))) {
-    for (i = 0; hp + i <= histptr && hp[i]; i++)
-      fprintf(fh, "%s%c", hp[i], '\0');
-    fclose(fh);
+  if ((fd = open(hname, O_WRONLY | O_CREAT | O_TRUNC | O_EXLOCK, 0777)) != -1) {
+    /* Remove anything written before we got the lock */
+    ftruncate(fd, 0);
+    if ((fh = fdopen(fd, "w")) != NULL) {
+      for (i = 0; hp + i <= histptr && hp[i]; i++)
+        fprintf(fh, "%s%c", hp[i], '\0');
+      fclose(fh);
+    }
   }
 }