It is not generally true that if (unsigned)a*(unsigned)b overflows,

then the result is less than 'a'.

diff --git a/sysdeps/generic/strtol.c b/sysdeps/generic/strtol.c
index 6ba2960..42da792 100644 (file)
--- a/sysdeps/generic/strtol.c
+++ b/sysdeps/generic/strtol.c
@@ -348,6 +348,7 @@ INTERNAL (strtol) (nptr, endptr, base, group LOCALE_PARAM)
   if (sizeof (long int) != sizeof (LONG int))
     {
       unsigned long int j = 0;
+      unsigned long int jmax = ULONG_MAX / base;
 
       for (;c != L_('\0'); c = *++s)
        {
@@ -362,18 +363,14 @@ INTERNAL (strtol) (nptr, endptr, base, group LOCALE_PARAM)
          if ((int) c >= base)
            break;
          /* Note that we never can have an overflow.  */
-         else
+         else if (j >= jmax)
            {
-             unsigned long int jj = j * (unsigned long int) base;
-             if (jj < j)
-               {
-                 /* We have an overflow.  Now use the long representation.  */
-                 i = (unsigned LONG int) j;
-                 goto use_long;
-               }
-             j = jj;
-             j += c;
+             /* We have an overflow.  Now use the long representation.  */
+             i = (unsigned LONG int) j;
+             goto use_long;
            }
+         else
+           j = j * (unsigned long int) base + c;
        }
 
       i = (unsigned LONG int) j;