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From: | Eric Blake |
Subject: | Re: [Qemu-devel] [PATCH v2 2/9] cutils: Fix qemu_strtosz() & friends to reject non-finite sizes |
Date: | Tue, 20 Nov 2018 10:29:39 -0600 |
User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.0 |
On 11/20/18 3:25 AM, David Hildenbrand wrote:
qemu_strtosz() & friends reject NaNs, but happily accept inifities.
s/inifities/infinities/
They shouldn't. Fix that. The fix makes use of qemu_strtod_finite(). To avoid ugly casts, change the @end parameter of qemu_strtosz() & friends from char ** to const char **. Also, add two test cases, testing that "inf" and "NaN" are properly rejected. Signed-off-by: David Hildenbrand <address@hidden> --- include/qemu/cutils.h | 6 +++--- monitor.c | 2 +- tests/test-cutils.c | 24 +++++++++++++++++------- util/cutils.c | 16 +++++++--------- 4 files changed, 28 insertions(+), 20 deletions(-)
+++ b/util/cutils.c @@ -206,20 +206,18 @@ static int64_t suffix_mul(char suffix, int64_t unit) * in *end, if not NULL. Return -ERANGE on overflow, Return -EINVAL on
Pre-existing, but since you're touching this area: the second 'Return' is unusual capitalization for being mid-sentence. You could even s/Return/of/
* other error. */ -static int do_strtosz(const char *nptr, char **end, +static int do_strtosz(const char *nptr, const char **end, const char default_suffix, int64_t unit, uint64_t *result) { int retval; - char *endptr; + const char *endptr; unsigned char c; int mul_required = 0; double val, mul, integral, fraction;- errno = 0;- val = strtod(nptr, &endptr); - if (isnan(val) || endptr == nptr || errno != 0) { - retval = -EINVAL; + retval = qemu_strtod_finite(nptr, &endptr, &val); + if (retval) { goto out;
Here, retval can be -EINVAL (for failure to parse, or encountering "inf" or "NaN") or -ERANGE (overflow, underflow)...
} fraction = modf(val, &integral); @@ -259,17 +257,17 @@ out:
out: if (end) { *end = endptr; } else if (*endptr) { retval = -EINVAL; }
return retval;
...if the failure was -EINVAL due to trailing garbage or empty string, nothing changes. If the failure was -EINVAL due to "inf", and the user passed in 'end', then 'end' now points to the beginning of "inf" instead of the end (probably okay). If the failure was -EINVAL due to "inf" and the user gave NULL for 'end', then we slam retval back to -EINVAL (no change). If the failure was -ERANGE, then there is no trailing garbage, so *endptr had better be NULL, and we still fail with -ERANGE. Any other way to reach the out label is unchanged from earlier logic.
It's some hairy code to think about, but I can't find anything wrong with it. Typo fixes are minor, so
Reviewed-by: Eric Blake <address@hidden> -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org
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