On 2/5/21 4:25 AM, Vladimir Sementsov-Ogievskiy wrote:
> 04.02.2021 22:07, Eric Blake wrote:
>> Supporting '0x20M' looks odd, particularly since we have an 'E' suffix
>
> What about also deprecating 'E' suffix? (just my problem of reviewing
> previous patch)
No, we want to keep '1E' as a valid way to spell 1 exabyte. That has
uses in the wild (admittedly corner-case, as that is a LOT of storage).
It is only '0x1E' where the use of 'E' as a hex digit has priority over
'E' as a suffix meaning exabyte.
>
>> that is ambiguous between a hex digit and the extremely large exibyte
>> suffix, as well as a 'B' suffix for bytes. In practice, people using
>> hex inputs are specifying values in bytes (and would have written
>> 0x2000000, or possibly relied on default_suffix in the case of
>> qemu_strtosz_MiB), and the use of scaling suffixes makes the most
>> sense for inputs in decimal (where the user would write 32M). But
>> rather than outright dropping support for hex-with-suffix, let's
>> follow our deprecation policy. Sadly, since qemu_strtosz() does not
>> have an Err** parameter, we pollute to stderr.
>>
>> Signed-off-by: Eric Blake <eblake@xxxxxxxxxx>
>> ---
>> +++ b/util/cutils.c
>> @@ -264,7 +264,7 @@ static int do_strtosz(const char *nptr, const char
>> **end,
>> int retval;
>> const char *endptr;
>> unsigned char c;
>> - bool mul_required = false;
>> + bool mul_required = false, hex = false;
>> uint64_t val;
>> int64_t mul;
>> double fraction = 0.0;
>> @@ -309,6 +309,10 @@ static int do_strtosz(const char *nptr, const
>> char **end,
>
> you forget to set hex to true in corresponding if(){...}
>
>> c = *endptr;
>> mul = suffix_mul(c, unit);
>> if (mul > 0) {
>> + if (hex) {
>> + fprintf(stderr, "Using a multiplier suffix on hex numbers "
>> + "is deprecated: %s\n", nptr);
>> + }
D'oh. Now I get to rerun my tests to see when the warning triggers.
>> endptr++;
>> } else {
>> mul = suffix_mul(default_suffix, unit);
>
> should we also deprecate hex where default_suffix is not 'B' ?
That's exactly what this patch is (supposed to be) doing. If we parsed
a hex number, and there was an explicit suffix at all (which is
necessarily neither 'B' nor 'E', since those were already consumed while
parsing the hex number), issue a warning.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org
