Re: [PULL 06/21] test-cutils: Test more integer corner cases

[Eric Blake]

On Thu, Jun 01, 2023 at 05:02:50PM -0500, Eric Blake wrote:
> We have quite a few undertested and underdocumented integer parsing
> corner cases.  To ensure that any changes we make in the code are
> intentional rather than accidental semantic changes, it is time to add
> more unit tests of existing behavior.
> 
>  static void test_qemu_strtol_overflow(void)
>  {
> -    const char *str = "99999999999999999999999999999999999999999999";
> +    const char *str;
> +    const char *endptr;
> +    long res;
> +    int err;
> +
> +    /* 1 more than LONG_MAX */
> +    str = LONG_MAX == INT_MAX ? "2147483648" : "9223372036854775808";
> +    endptr = "somewhere";
> +    res = 999;
> +    err = qemu_strtol(str, &endptr, 0, &res);
> +    g_assert_cmpint(err, ==, -ERANGE);
> +    g_assert_cmpint(res, ==, LONG_MAX);
> +    g_assert_true(endptr == str + strlen(str));
> +
> +    if (LONG_MAX == INT_MAX) {
> +        str = "0xffffffff00000001"; /* ULLONG_MAX - UINT_MAX + 1 (not 1) */
> +        endptr = "somewhere";
> +        res = 999;
> +        err = qemu_strtol(str, &endptr, 0, &res);
> +        g_assert_cmpint(err, ==, -ERANGE);
> +        g_assert_cmpint(res, ==, LONG_MIN);
> +        g_assert_true(endptr == str + strlen(str));
> +    }

Copy-paste failure, but only visible on platforms like mingw where
long is 32-bits; I had copied this...

> 
>  static void test_qemu_strtol_underflow(void)
>  {
> -    const char *str = "-99999999999999999999999999999999999999999999";
> -    char f = 'X';
> -    const char *endptr = &f;
> -    long res = 999;
> +    const char *str;
> +    const char *endptr;
> +    long res;
>      int err;
> 
> +    /* 1 less than LONG_MIN */
> +    str = LONG_MIN == INT_MIN ? "-2147483649" : "-9223372036854775809";
> +    endptr = "somewhere";
> +    res = 999;
>      err = qemu_strtol(str, &endptr, 0, &res);
> +    g_assert_cmpint(err, ==, -ERANGE);
> +    g_assert_cmpint(res, ==, LONG_MIN);
> +    g_assert_true(endptr == str + strlen(str));
> 
> +    if (LONG_MAX == INT_MAX) {
> +        str = "-18446744073709551615"; /* -UINT64_MAX (not 1) */
> +        endptr = "somewhere";
> +        res = 999;
> +        err = qemu_strtol(str, &endptr, 0, &res);
> +        g_assert_cmpint(err, ==, -ERANGE);
> +        g_assert_cmpint(res, ==, LONG_MIN);
> +        g_assert_true(endptr == str + strlen(str));
> +    }

...from here, but failed to s/MIN/MAX/ when dealing with the changed
sign.  Yay for CI catching it.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org