cutils: Improve qemu_strtosz handling of fractions

We have several limitations and bugs worth fixing; they are
inter-related enough that it is not worth splitting this patch into
smaller pieces:

*

cutils: Improve qemu_strtosz handling of fractions

We have several limitations and bugs worth fixing; they are
inter-related enough that it is not worth splitting this patch into
smaller pieces:

* ".5k" should work to specify 512, just as "0.5k" does
* "1.9999k" and "1." + "9"*50 + "k" should both produce the same
result of 2048 after rounding
* "1." + "0"*350 + "1B" should not be treated the same as "1.0B";
underflow in the fraction should not be lost
* "7.99e99" and "7.99e999" look similar, but our code was doing a
read-out-of-bounds on the latter because it was not expecting ERANGE
due to overflow. While we document that scientific notation is not
supported, and the previous patch actually fixed
qemu_strtod_finite() to no longer return ERANGE overflows, it is
easier to pre-filter than to try and determine after the fact if
strtod() consumed more than we wanted. Note that this is a
low-level semantic change (when endptr is not NULL, we can now
successfully parse with a scale of 'E' and then report trailing
junk, instead of failing outright with EINVAL); but an earlier
commit already argued that this is not a high-level semantic change
since the only caller passing in a non-NULL endptr also checks that
the tail is whitespace-only.

Fixes: https://gitlab.com/qemu-project/qemu/-/issues/1629
Fixes: cf923b78 ("utils: Improve qemu_strtosz() to have 64 bits of precision", 6.0.0)
Fixes: 7625a1ed ("utils: Use fixed-point arithmetic in qemu_strtosz", 6.0.0)
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-20-eblake@redhat.com>
[eblake: tweak function comment for accuracy]

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cutils: Improve qemu_strtod* error paths

Previous patches changed all integral qemu_strto*() error paths to
guarantee that *value is never left uninitialized. Do likewise for
qemu_strtod. Also, ti

cutils: Improve qemu_strtod* error paths

Previous patches changed all integral qemu_strto*() error paths to
guarantee that *value is never left uninitialized. Do likewise for
qemu_strtod. Also, tighten qemu_strtod_finite() to never return a
non-finite value (prior to this patch, we were rejecting "inf" with
-EINVAL and unspecified result 0.0, but failing "9e999" with -ERANGE
and HUGE_VAL - which is infinite on IEEE machines - despite our
function claiming to recognize only finite values).

Auditing callers, we have no external callers of qemu_strtod, and
among the callers of qemu_strtod_finite:

- qapi/qobject-input-visitor.c:qobject_input_type_number_keyval() and
qapi/string-input-visitor.c:parse_type_number() which reject all
errors (does not matter what we store)

- utils/cutils.c:do_strtosz() incorrectly assumes that *endptr points
to '.' on all failures (that is, it is not distinguishing between
EINVAL and ERANGE; and therefore still does the WRONG THING for
"9.9e999". The change here does not entirely fix that (a later
patch will tackle this more systematically), but at least it fixes
the read-out-of-bounds first diagnosed in
https://gitlab.com/qemu-project/qemu/-/issues/1629

- our testsuite, which we can update to match what we document

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
CC: qemu-stable@nongnu.org
Message-Id: <20230522190441.64278-19-eblake@redhat.com>

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cutils: Use parse_uint in qemu_strtosz for negative rejection

Rather than open-coding two different ways to check for an unwanted
negative sign, reuse the same code in both functions. That way, if

cutils: Use parse_uint in qemu_strtosz for negative rejection

Rather than open-coding two different ways to check for an unwanted
negative sign, reuse the same code in both functions. That way, if we
decide down the road to accept "-0" instead of rejecting it, we have
fewer places to change. Also, it means we now get ERANGE instead of
EINVAL for negative values in qemu_strtosz, which is reasonable for
what it represents. This in turn changes the expected output of a
couple of iotests.

The change is not quite complete: negative fractional scaled values
can trip us up. This will be fixed in a later patch addressing other
issues with fractional scaled values.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-18-eblake@redhat.com>

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cutils: Set value in all integral qemu_strto* error paths

Our goal in writing qemu_strtoi() and friends is to have an interface
harder to abuse than libc's strtol(). Leaving the return value
uninit

cutils: Set value in all integral qemu_strto* error paths

Our goal in writing qemu_strtoi() and friends is to have an interface
harder to abuse than libc's strtol(). Leaving the return value
uninitialized on some but not all error paths does not lend itself
well to this goal; and our documentation wasn't helpful on what to
expect.

Note that the previous patch changed all qemu_strtosz() EINVAL error
paths to slam value to 0 rather than stay uninitialized, even when the
EINVAL eror occurs because of trailing junk. But for the remaining
integral qemu_strto*, it's easier to return the parsed value than to
force things back to zero, in part because of how check_strtox_error
works; in part because people expect that from libc strto* (while
there is no libc strtosz to compare to), and in part because doing so
creates less churn in the testsuite.

Here, the list of affected callers is much longer ('git grep
"qemu_strto[ui]" "*.c" "**/*.c" | grep -v tests/ |wc -l' outputs 107,
although a few of those are the implementation in in cutils.c), so
touching as little as possible is the wisest course of action.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-17-eblake@redhat.com>

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cutils: Set value in all qemu_strtosz* error paths

Making callers determine whether or not *value was populated on error
is not nice for usability. Pre-patch, we have unit tests that check
that *re

cutils: Set value in all qemu_strtosz* error paths

Making callers determine whether or not *value was populated on error
is not nice for usability. Pre-patch, we have unit tests that check
that *result is left unchanged on most EINVAL errors and set to 0 on
many ERANGE errors. This is subtly different from libc strtoumax()
behavior which returns UINT64_MAX on ERANGE errors, as well as
different from our parse_uint() which slams to 0 on EINVAL on the
grounds that we want our functions to be harder to mis-use than
strtoumax().

Let's audit callers:

- hw/core/numa.c:parse_numa() fixed in the previous patch to check for
errors

- migration/migration-hmp-cmds.c:hmp_migrate_set_parameter(),
monitor/hmp.c:monitor_parse_arguments(),
qapi/opts-visitor.c:opts_type_size(),
qapi/qobject-input-visitor.c:qobject_input_type_size_keyval(),
qemu-img.c:cvtnum_full(), qemu-io-cmds.c:cvtnum(),
target/i386/cpu.c:x86_cpu_parse_featurestr(), and
util/qemu-option.c:parse_option_size() appear to reject all failures
(although some with distinct messages for ERANGE as opposed to
EINVAL), so it doesn't matter what is in the value parameter on
error.

- All remaining callers are in the testsuite, where we can tweak our
expectations to match our new desired behavior.

Advancing to the end of the string parsed on overflow (ERANGE), while
still returning 0, makes sense (UINT64_MAX as a size is unlikely to be
useful); likewise, our size parsing code is complex enough that it's
easier to always return 0 when endptr is NULL but trailing garbage was
found, rather than trying to return the value of the prefix actually
parsed (no current caller cared about the value of the prefix).

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-16-eblake@redhat.com>

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test-cutils: Add more coverage to qemu_strtosz

Add some more strings that the user might send our way. In
particular, some of these additions include FIXME comments showing
where our parser doesn't

test-cutils: Add more coverage to qemu_strtosz

Add some more strings that the user might send our way. In
particular, some of these additions include FIXME comments showing
where our parser doesn't quite behave the way we want.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-15-eblake@redhat.com>

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cutils: Allow NULL str in qemu_strtosz

All the other qemu_strto* and parse_uint allow a NULL str. Having
qemu_strtosz not crash on qemu_strtosz(NULL, NULL, &value) is an easy
fix that adds some con

cutils: Allow NULL str in qemu_strtosz

All the other qemu_strto* and parse_uint allow a NULL str. Having
qemu_strtosz not crash on qemu_strtosz(NULL, NULL, &value) is an easy
fix that adds some consistency between our string parsers.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-13-eblake@redhat.com>

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test-cutils: Refactor qemu_strtosz tests for less boilerplate

No need to copy-and-paste lots of boilerplate per string tested, when
we can consolidate that behind helper functions. Plus, this adds

test-cutils: Refactor qemu_strtosz tests for less boilerplate

No need to copy-and-paste lots of boilerplate per string tested, when
we can consolidate that behind helper functions. Plus, this adds a
bit more coverage (we now test all strings both with and without
endptr, whereas before some tests skipped the NULL endptr case), which
exposed a SEGFAULT on qemu_strtosz(NULL, NULL, &val) that will be
fixed in an upcoming patch.

Note that duplicating boilerplate has one advantage lost here - a
failed test tells you which line number failed; but a helper function
does not show the call stack that reached the failure. Since we call
the helper more than once within many of the "unit tests", even the
unit test name doesn't point out which call is failing. But that only
matters when tests fail (they normally pass); at which point I'm
debugging the failures under gdb anyways, so I'm not too worried about
it.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-12-eblake@redhat.com>

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test-cutils: Prepare for upcoming semantic change in qemu_strtosz

A quick search for 'qemu_strtosz' in the code base shows that outside
of the testsuite, the ONLY place that passes a non-NULL pointe

test-cutils: Prepare for upcoming semantic change in qemu_strtosz

A quick search for 'qemu_strtosz' in the code base shows that outside
of the testsuite, the ONLY place that passes a non-NULL pointer to
@endptr of any variant of a size parser is in hmp.c (the 'o' parser of
monitor_parse_arguments), and that particular caller warns of
"extraneous characters at the end of line" unless the trailing bytes
are purely whitespace. Thus, it makes no semantic difference at the
high level whether we parse "1.5e1k" as "1" + ".5e1" + "k" (an attempt
to use scientific notation in strtod with a scaling suffix of 'k' with
no trailing junk, but which qemu_strtosz says should fail with
EINVAL), or as "1.5e" + "1k" (a valid size with scaling suffix of 'e'
for exabytes, followed by two junk bytes) - either way, any user
passing such a string will get an error message about a parse failure.

However, an upcoming patch to qemu_strtosz will fix other corner case
bugs in handling the fractional portion of a size, and in doing so, it
is easier to declare that qemu_strtosz() itself stops parsing at the
first 'e' rather than blindly consuming whatever strtod() will
recognize. Once that is fixed, the difference will be visible at the
low level (getting a valid parse with trailing garbage when @endptr is
non-NULL, while continuing to get -EINVAL when @endptr is NULL); this
is easier to demonstrate by moving the affected strings from
test_qemu_strtosz_invalid() (which declares them as always -EINVAL) to
test_qemu_strtosz_trailing() (where @endptr affects behavior, for now
with FIXME comments).

Note that a similar argument could be made for having "0x1.5" or
"0x1M" parse as 0x1 with ".5" or "M" as trailing junk, instead of
blindly treating it as -EINVAL; however, as these cases do not suffer
from the same problems as floating point, they are not worth changing
at this time.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-11-eblake@redhat.com>

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test-cutils: Add coverage of qemu_strtod

It's hard to tweak code for consistency if I can't prove what will or
won't break from those tweaks. Time to add unit tests for
qemu_strtod() and qemu_strto

test-cutils: Add coverage of qemu_strtod

It's hard to tweak code for consistency if I can't prove what will or
won't break from those tweaks. Time to add unit tests for
qemu_strtod() and qemu_strtod_finite().

Among other things, I wrote a check whether we have C99 semantics for
strtod("0x1") (which MUST parse hex numbers) rather than C89 (which
must stop parsing at 'x'). These days, I suspect that is okay; but if
it fails CI checks, knowing the difference will help us decide what we
want to do about it. Note that C2x, while not final at the time of
this patch, has been considering whether to make strtol("0b1") parse
as 1 with no slop instead of the C17 parse of 0 with slop "b1"; that
decision may also bleed over to strtod(). But for now, I didn't think
it worth adding unit tests on that front (to strtol or strtod) as
things may still change.

Likewise, there are plenty more corner cases of strtod proper that I
don't explicitly test here, but there are enough unit tests added here
that it covers all the branches reached in our wrappers. In
particular, it demonstrates the difference on when *value is left
uninitialized, which an upcoming patch will normalize.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-10-eblake@redhat.com>

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cutils: Allow NULL endptr in parse_uint()

All the qemu_strto*() functions permit a NULL endptr, just like their
libc counterparts, leaving parse_uint() as the oddball that caused
SEGFAULT on NULL an

cutils: Allow NULL endptr in parse_uint()

All the qemu_strto*() functions permit a NULL endptr, just like their
libc counterparts, leaving parse_uint() as the oddball that caused
SEGFAULT on NULL and required the user to call parse_uint_full()
instead. Relax things for consistency, even though the testsuite is
the only impacted caller. Add one more unit test to ensure even
parse_uint_full(NULL, 0, &value) works. This also fixes our code to
uniformly favor EINVAL over ERANGE when both apply.

Also fixes a doc mismatch @v vs. a parameter named value.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-9-eblake@redhat.com>

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cutils: Adjust signature of parse_uint[_full]

It's already confusing that we have two very similar functions for
wrapping the parse of a 64-bit unsigned value, differing mainly on
whether they permi

cutils: Adjust signature of parse_uint[_full]

It's already confusing that we have two very similar functions for
wrapping the parse of a 64-bit unsigned value, differing mainly on
whether they permit leading '-'. Adjust the signature of parse_uint()
and parse_uint_full() to be like all of qemu_strto*(): put the result
parameter last, use the same types (uint64_t and unsigned long long
have the same width, but are not always the same type), and mark
endptr const (this latter change only affects the rare caller of
parse_uint). Adjust all callers in the tree.

While at it, note that since cutils.c already includes:

QEMU_BUILD_BUG_ON(sizeof(int64_t) != sizeof(long long));

we are guaranteed that the result of parse_uint* cannot exceed
UINT64_MAX (or the build would have failed), so we can drop
pre-existing dead comparisons in opts-visitor.c that were never false.

Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-8-eblake@redhat.com>
[eblake: Drop dead code spotted by Markus]
Signed-off-by: Eric Blake <eblake@redhat.com>

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cutils: Fix wraparound parsing in qemu_strtoui

While we were matching 32-bit strtol in qemu_strtoi, our use of a
64-bit parse was leaking through for some inaccurate answers in
qemu_strtoui in compa

cutils: Fix wraparound parsing in qemu_strtoui

While we were matching 32-bit strtol in qemu_strtoi, our use of a
64-bit parse was leaking through for some inaccurate answers in
qemu_strtoui in comparison to a 32-bit strtoul (see the unit test for
examples). The comment for that function even described what we have
to do for a correct parse, but didn't implement it correctly: since
strtoull checks for overflow against the wrong values and then
negates, we have to temporarily undo negation before checking for
overflow against our desired value.

Our int wrappers would be a lot easier to write if libc had a
guaranteed 32-bit parser even on platforms with 64-bit long.

Whether we parse C2x binary strings like "0b1000" is currently up to
what libc does; our unit tests intentionally don't cover that at the
moment, though.

Fixes: 473a2a331e ("cutils: add qemu_strtoi & qemu_strtoui parsers for int/unsigned int types", v2.12.0)
Signed-off-by: Eric Blake <eblake@redhat.com>
CC: qemu-stable@nongnu.org
Message-Id: <20230522190441.64278-6-eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>

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test-cutils: Test more integer corner cases

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 t

test-cutils: Test more integer corner cases

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.

In particular, this demonstrates that parse_uint() and qemu_strtou64()
behave differently. For "-0", it's hard to argue why parse_uint needs
to reject it (it's not a negative integer), but the documentation sort
of mentions it; but it is intentional that all other negative values
are treated as ERANGE with value 0 (compared to qemu_strtou64()
treating "-2" as success and UINT64_MAX-1, for example).

Also, when mixing overflow/underflow with a check for no trailing
junk, parse_uint_full favors ERANGE over EINVAL, while qemu_strto[iu]*
favor EINVAL. This behavior is outside the C standard, so we can pick
whatever we want, but it would be nice to be consistent.

Note that C requires that "9223372036854775808" fail strtoll() with
ERANGE/INT64_MAX, but "-9223372036854775808" pass with INT64_MIN; we
weren't testing this. For strtol(), the behavior depends on whether
long is 32- or 64-bits (the cutoff point either being the same as
strtoll() or at "-2147483648"). Meanwhile, C is clear that
"-18446744073709551615" pass stroull() (but not strtoll) with value 1,
even though we want it to fail parse_uint(). And although
qemu_strtoui() has no C counterpart, it makes more sense if we design
it like 32-bit strtoul() (that is, where "-4294967296" be an alternate
acceptable spelling for "1", but "-0xffffffff00000001" should be
treated as overflow and return 0xffffffff rather than 1). We aren't
there yet, so some of the tests added in this patch have FIXME
comments.

However, note that C2x will (likely) be adding a SILENT semantic
change, where C17 strtol("0b1", &ep, 2) returns 0 with ep="b1", but
C2x will have it return 1 with ep="". I did not feel like adding
testing for those corner cases, in part because the next version of C
is not standard and libc support for binary parsing is not yet
wide-spread (as of this patch, glibc.git still misparses bare "0b":
https://sourceware.org/bugzilla/show_bug.cgi?id=30371).

Message-Id: <20230522190441.64278-5-eblake@redhat.com>
[eblake: fix a few typos spotted by Hanna]
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
[eblake: fix typo on platforms with 32-bit long]
Signed-off-by: Eric Blake <eblake@redhat.com>

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test-cutils: Test integral qemu_strto* value on failures

We are inconsistent on the contents of *value after a strto* parse
failure. I found the following behaviors:

- parse_uint() and parse_uint_

test-cutils: Test integral qemu_strto* value on failures

We are inconsistent on the contents of *value after a strto* parse
failure. I found the following behaviors:

- parse_uint() and parse_uint_full(), which document that *value is
slammed to 0 on all EINVAL failures and 0 or UINT_MAX on ERANGE
failures, and has unit tests for that (note that parse_uint requires
non-NULL endptr, and does not fail with EINVAL for trailing junk)

- qemu_strtosz(), which leaves *value untouched on all failures (both
EINVAL and ERANGE), and has unit tests but not documentation for
that

- qemu_strtoi() and other integral friends, which document *value on
ERANGE failures but is unspecified on EINVAL (other than implicitly
by comparison to libc strto*); there, *value is untouched for NULL
string, slammed to 0 on no conversion, and left at the prefix value
on NULL endptr; unit tests do not consistently check the value

- qemu_strtod(), which documents *value on ERANGE failures but is
unspecified on EINVAL; there, *value is untouched for NULL string,
slammed to 0.0 for no conversion, and left at the prefix value on
NULL endptr; there are no unit tests (other than indirectly through
qemu_strtosz)

- qemu_strtod_finite(), which documents *value on ERANGE failures but
is unspecified on EINVAL; there, *value is left at the prefix for
'inf' or 'nan' and untouched in all other cases; there are no unit
tests (other than indirectly through qemu_strtosz)

Upcoming patches will change behaviors for consistency, but it's best
to first have more unit test coverage to see the impact of those
changes.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-4-eblake@redhat.com>

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test-cutils: Use g_assert_cmpuint where appropriate

When debugging test failures, seeing unsigned values as large positive
values rather than negative values matters (assuming glib 2.78+; given
that

test-cutils: Use g_assert_cmpuint where appropriate

When debugging test failures, seeing unsigned values as large positive
values rather than negative values matters (assuming glib 2.78+; given
that I just fixed a bug in glib 2.76 [1] where g_assert_cmpuint
displays signed instead of unsigned values). No impact when the test
is passing, but using a consistent style will matter more in upcoming
test additions. Also, some tests are better with cmphex.

While at it, fix some spacing and minor typing issues spotted nearby.

[1] https://gitlab.gnome.org/GNOME/glib/-/issues/2997

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-3-eblake@redhat.com>

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test-cutils: Avoid g_assert in unit tests

glib documentation[1] is clear: g_assert() should be avoided in unit
tests because it is ineffective if G_DISABLE_ASSERT is defined; unit
tests should stick

test-cutils: Avoid g_assert in unit tests

glib documentation[1] is clear: g_assert() should be avoided in unit
tests because it is ineffective if G_DISABLE_ASSERT is defined; unit
tests should stick to constructs based on g_assert_true() instead.
Note that since commit 262a69f428, we intentionally state that you
cannot define G_DISABLE_ASSERT while building qemu; but our code can
be copied to other projects without that restriction, so we should be
consistent.

For most of the replacements in this patch, using g_assert_cmpstr()
would be a regression in quality - although it would helpfully display
the string contents of both pointers on test failure, here, we really
do care about pointer equality, not just string content equality. But
when a NULL pointer is expected, g_assert_null works fine.

[1] https://libsoup.org/glib/glib-Testing.html#g-assert

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230522190441.64278-2-eblake@redhat.com>

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cutils: Improve qemu_strtosz handling of fractions

We have several limitations and bugs worth fixing; they are
inter-related enough that it is not worth splitting this patch into
smaller pieces:

*

cutils: Improve qemu_strtosz handling of fractions

We have several limitations and bugs worth fixing; they are
inter-related enough that it is not worth splitting this patch into
smaller pieces:

* ".5k" should work to specify 512, just as "0.5k" does
* "1.9999k" and "1." + "9"*50 + "k" should both produce the same
result of 2048 after rounding
* "1." + "0"*350 + "1B" should not be treated the same as "1.0B";
underflow in the fraction should not be lost
* "7.99e99" and "7.99e999" look similar, but our code was doing a
read-out-of-bounds on the latter because it was not expecting ERANGE
due to overflow. While we document that scientific notation is not
supported, and the previous patch actually fixed
qemu_strtod_finite() to no longer return ERANGE overflows, it is
easier to pre-filter than to try and determine after the fact if
strtod() consumed more than we wanted. Note that this is a
low-level semantic change (when endptr is not NULL, we can now
successfully parse with a scale of 'E' and then report trailing
junk, instead of failing outright with EINVAL); but an earlier
commit already argued that this is not a high-level semantic change
since the only caller passing in a non-NULL endptr also checks that
the tail is whitespace-only.

Fixes: https://gitlab.com/qemu-project/qemu/-/issues/1629
Fixes: cf923b78 ("utils: Improve qemu_strtosz() to have 64 bits of precision", 6.0.0)
Fixes: 7625a1ed ("utils: Use fixed-point arithmetic in qemu_strtosz", 6.0.0)
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-20-eblake@redhat.com>
[eblake: tweak function comment for accuracy]

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cutils: Improve qemu_strtod* error paths

Previous patches changed all integral qemu_strto*() error paths to
guarantee that *value is never left uninitialized. Do likewise for
qemu_strtod. Also, ti

cutils: Improve qemu_strtod* error paths

Previous patches changed all integral qemu_strto*() error paths to
guarantee that *value is never left uninitialized. Do likewise for
qemu_strtod. Also, tighten qemu_strtod_finite() to never return a
non-finite value (prior to this patch, we were rejecting "inf" with
-EINVAL and unspecified result 0.0, but failing "9e999" with -ERANGE
and HUGE_VAL - which is infinite on IEEE machines - despite our
function claiming to recognize only finite values).

Auditing callers, we have no external callers of qemu_strtod, and
among the callers of qemu_strtod_finite:

- qapi/qobject-input-visitor.c:qobject_input_type_number_keyval() and
qapi/string-input-visitor.c:parse_type_number() which reject all
errors (does not matter what we store)

- utils/cutils.c:do_strtosz() incorrectly assumes that *endptr points
to '.' on all failures (that is, it is not distinguishing between
EINVAL and ERANGE; and therefore still does the WRONG THING for
"9.9e999". The change here does not entirely fix that (a later
patch will tackle this more systematically), but at least it fixes
the read-out-of-bounds first diagnosed in
https://gitlab.com/qemu-project/qemu/-/issues/1629

- our testsuite, which we can update to match what we document

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
CC: qemu-stable@nongnu.org
Message-Id: <20230522190441.64278-19-eblake@redhat.com>

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cutils: Use parse_uint in qemu_strtosz for negative rejection

Rather than open-coding two different ways to check for an unwanted
negative sign, reuse the same code in both functions. That way, if

cutils: Use parse_uint in qemu_strtosz for negative rejection

Rather than open-coding two different ways to check for an unwanted
negative sign, reuse the same code in both functions. That way, if we
decide down the road to accept "-0" instead of rejecting it, we have
fewer places to change. Also, it means we now get ERANGE instead of
EINVAL for negative values in qemu_strtosz, which is reasonable for
what it represents. This in turn changes the expected output of a
couple of iotests.

The change is not quite complete: negative fractional scaled values
can trip us up. This will be fixed in a later patch addressing other
issues with fractional scaled values.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-18-eblake@redhat.com>

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cutils: Set value in all integral qemu_strto* error paths

Our goal in writing qemu_strtoi() and friends is to have an interface
harder to abuse than libc's strtol(). Leaving the return value
uninit

cutils: Set value in all integral qemu_strto* error paths

Our goal in writing qemu_strtoi() and friends is to have an interface
harder to abuse than libc's strtol(). Leaving the return value
uninitialized on some but not all error paths does not lend itself
well to this goal; and our documentation wasn't helpful on what to
expect.

Note that the previous patch changed all qemu_strtosz() EINVAL error
paths to slam value to 0 rather than stay uninitialized, even when the
EINVAL eror occurs because of trailing junk. But for the remaining
integral qemu_strto*, it's easier to return the parsed value than to
force things back to zero, in part because of how check_strtox_error
works; in part because people expect that from libc strto* (while
there is no libc strtosz to compare to), and in part because doing so
creates less churn in the testsuite.

Here, the list of affected callers is much longer ('git grep
"qemu_strto[ui]" "*.c" "**/*.c" | grep -v tests/ |wc -l' outputs 107,
although a few of those are the implementation in in cutils.c), so
touching as little as possible is the wisest course of action.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-17-eblake@redhat.com>

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cutils: Set value in all qemu_strtosz* error paths

Making callers determine whether or not *value was populated on error
is not nice for usability. Pre-patch, we have unit tests that check
that *re

cutils: Set value in all qemu_strtosz* error paths

Making callers determine whether or not *value was populated on error
is not nice for usability. Pre-patch, we have unit tests that check
that *result is left unchanged on most EINVAL errors and set to 0 on
many ERANGE errors. This is subtly different from libc strtoumax()
behavior which returns UINT64_MAX on ERANGE errors, as well as
different from our parse_uint() which slams to 0 on EINVAL on the
grounds that we want our functions to be harder to mis-use than
strtoumax().

Let's audit callers:

- hw/core/numa.c:parse_numa() fixed in the previous patch to check for
errors

- migration/migration-hmp-cmds.c:hmp_migrate_set_parameter(),
monitor/hmp.c:monitor_parse_arguments(),
qapi/opts-visitor.c:opts_type_size(),
qapi/qobject-input-visitor.c:qobject_input_type_size_keyval(),
qemu-img.c:cvtnum_full(), qemu-io-cmds.c:cvtnum(),
target/i386/cpu.c:x86_cpu_parse_featurestr(), and
util/qemu-option.c:parse_option_size() appear to reject all failures
(although some with distinct messages for ERANGE as opposed to
EINVAL), so it doesn't matter what is in the value parameter on
error.

- All remaining callers are in the testsuite, where we can tweak our
expectations to match our new desired behavior.

Advancing to the end of the string parsed on overflow (ERANGE), while
still returning 0, makes sense (UINT64_MAX as a size is unlikely to be
useful); likewise, our size parsing code is complex enough that it's
easier to always return 0 when endptr is NULL but trailing garbage was
found, rather than trying to return the value of the prefix actually
parsed (no current caller cared about the value of the prefix).

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-16-eblake@redhat.com>

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test-cutils: Add more coverage to qemu_strtosz

Add some more strings that the user might send our way. In
particular, some of these additions include FIXME comments showing
where our parser doesn't

test-cutils: Add more coverage to qemu_strtosz

Add some more strings that the user might send our way. In
particular, some of these additions include FIXME comments showing
where our parser doesn't quite behave the way we want.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-15-eblake@redhat.com>

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cutils: Allow NULL str in qemu_strtosz

All the other qemu_strto* and parse_uint allow a NULL str. Having
qemu_strtosz not crash on qemu_strtosz(NULL, NULL, &value) is an easy
fix that adds some con

cutils: Allow NULL str in qemu_strtosz

All the other qemu_strto* and parse_uint allow a NULL str. Having
qemu_strtosz not crash on qemu_strtosz(NULL, NULL, &value) is an easy
fix that adds some consistency between our string parsers.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-13-eblake@redhat.com>

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test-cutils: Refactor qemu_strtosz tests for less boilerplate

No need to copy-and-paste lots of boilerplate per string tested, when
we can consolidate that behind helper functions. Plus, this adds

test-cutils: Refactor qemu_strtosz tests for less boilerplate

No need to copy-and-paste lots of boilerplate per string tested, when
we can consolidate that behind helper functions. Plus, this adds a
bit more coverage (we now test all strings both with and without
endptr, whereas before some tests skipped the NULL endptr case), which
exposed a SEGFAULT on qemu_strtosz(NULL, NULL, &val) that will be
fixed in an upcoming patch.

Note that duplicating boilerplate has one advantage lost here - a
failed test tells you which line number failed; but a helper function
does not show the call stack that reached the failure. Since we call
the helper more than once within many of the "unit tests", even the
unit test name doesn't point out which call is failing. But that only
matters when tests fail (they normally pass); at which point I'm
debugging the failures under gdb anyways, so I'm not too worried about
it.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-Id: <20230522190441.64278-12-eblake@redhat.com>

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