(integer_overflow): New function.

(eval4, eval3): Check for integer overflow.

diff --git a/src/expr.c b/src/expr.c
index c5b1ae87bf3bac0a9039448af947d02ce185efde..ab36350e58767767684d4ec639d0f37fb55c4fe4 100644 (file)
--- a/src/expr.c
+++ b/src/expr.c
@@ -175,6 +175,13 @@ syntax_error (void)
   error (EXPR_INVALID, 0, _("syntax error"));
 }
 
+/* Report an integer overflow for operation OP and exit.  */
+static void
+integer_overflow (char op)
+{
+  error (EXPR_FAILURE, ERANGE, "%c", op);
+}
+
 int
 main (int argc, char **argv)
 {
@@ -631,12 +638,26 @@ eval4 (bool evaluate)
          if (!toarith (l) || !toarith (r))
            error (EXPR_INVALID, 0, _("non-numeric argument"));
          if (fxn == multiply)
-           val = l->u.i * r->u.i;
+           {
+             val = l->u.i * r->u.i;
+             if (! (l->u.i == 0 || val / l->u.i == r->u.i))
+               integer_overflow ('*');
+           }
          else
            {
              if (r->u.i == 0)
                error (EXPR_INVALID, 0, _("division by zero"));
-             val = fxn == divide ? l->u.i / r->u.i : l->u.i % r->u.i;
+             if (l->u.i < - INTMAX_MAX && r->u.i == -1)
+               {
+                 /* Some x86-style hosts erroneously raise an
+                    exception for INT_MIN / -1 and INT_MIN % -1, so
+                    handle these problematic cases specially.  */
+                 if (fxn == divide)
+                   integer_overflow ('/');
+                 val = 0;
+               }
+             else
+               val = fxn == divide ? l->u.i / r->u.i : l->u.i % r->u.i;
            }
        }
       freev (l);
@@ -672,7 +693,18 @@ eval3 (bool evaluate)
        {
          if (!toarith (l) || !toarith (r))
            error (EXPR_INVALID, 0, _("non-numeric argument"));
-         val = fxn == plus ? l->u.i + r->u.i : l->u.i - r->u.i;
+         if (fxn == plus)
+           {
+             val = l->u.i + r->u.i;
+             if ((val < l->u.i) != (r->u.i < 0))
+               integer_overflow ('+');
+           }
+         else
+           {
+             val = l->u.i - r->u.i;
+             if ((l->u.i < val) != (r->u.i < 0))
+               integer_overflow ('-');
+           }
        }
       freev (l);
       freev (r);