04.02.2021 22:07, Eric Blake wrote:
We have multiple clients of qemu_strtosz (qemu-io, the opts visitor,
the keyval visitor), and it gets annoying that edge-case testing is
impacted by implicit rounding to 53 bits of precision due to parsing
with strtod(). As an example posted by Rich Jones:
$ nbdkit memory $(( 2**63 - 2**30 )) --run \
'build/qemu-io -f raw "$uri" -c "w -P 3 $(( 2**63 - 2**30 - 512 )) 512" '
write failed: Input/output error
because 9223372035781033472 got rounded to 0x7fffffffc0000000 which is
out of bounds.
It is also worth noting that our existing parser, by virtue of using
strtod(), accepts decimal AND hex numbers, even though test-cutils
previously lacked any coverage of the latter. We do have existing
clients that expect a hex parse to work (for example, iotest 33 using
qemu-io -c "write -P 0xa 0x200 0x400"), but strtod() parses "08" as 8
rather than as an invalid octal number, so we know there are no
clients that depend on octal. Our use of strtod() also means that
"0x1.8k" would actually parse as 1536 (the fraction is 8/16), rather
than 1843 (if the fraction were 8/10); but as this was not covered in
the testsuite, I have no qualms forbidding hex fractions as invalid,
so this patch declares that the use of fractions is only supported
with decimal input, and enhances the testsuite to document that.
Our previous use of strtod() meant that -1 parsed as a negative; now
that we parse with strtoull(), negative values can wrap around module
2^64, so we have to explicitly check whether the user passed in a '-'.
We also had no testsuite coverage of "1.1e0k", which happened to parse
under strtod() but is unlikely to occur in practice; as long as we are
making things more robust, it is easy enough to reject the use of
exponents in a strtod parse.
The fix is done by breaking the parse into an integer prefix (no loss
in precision), rejecting negative values (since we can no longer rely
on strtod() to do that), determining if a decimal or hexadecimal parse
was intended (with the new restriction that a fractional hex parse is
not allowed), and where appropriate, using a floating point fractional
parse (where we also scan to reject use of exponents in the fraction).
The bulk of the patch is then updates to the testsuite to match our
new precision, as well as adding new cases we reject (whether they
were rejected or inadvertenly accepted before).
Signed-off-by: Eric Blake <ebl...@redhat.com>
---
Note that this approach differs from what has been attempted in the
past; see the thread starting at
https://lists.gnu.org/archive/html/qemu-devel/2019-12/msg00852.html
That approach tried to parse both as strtoull and strtod and take
whichever was longer, but that was harder to document.
---
tests/test-cutils.c | 79 ++++++++++++++++++++++++++++++--------
tests/test-keyval.c | 24 +++++++++---
tests/test-qemu-opts.c | 20 +++++++---
util/cutils.c | 77 +++++++++++++++++++++++++++----------
tests/qemu-iotests/049.out | 7 +++-
5 files changed, 156 insertions(+), 51 deletions(-)
diff --git a/tests/test-cutils.c b/tests/test-cutils.c
index 1aa8351520ae..0c2c89d6f113 100644
--- a/tests/test-cutils.c
+++ b/tests/test-cutils.c
@@ -1960,6 +1960,13 @@ static void test_qemu_strtosz_simple(void)
g_assert_cmpint(res, ==, 0);
g_assert(endptr == str + 1);
+ /* Leading 0 gives decimal results, not octal */
+ str = "08";
+ err = qemu_strtosz(str, &endptr, &res);
+ g_assert_cmpint(err, ==, 0);
+ g_assert_cmpint(res, ==, 8);
+ g_assert(endptr == str + 2);
+
str = "12345";
err = qemu_strtosz(str, &endptr, &res);
g_assert_cmpint(err, ==, 0);
@@ -1970,7 +1977,7 @@ static void test_qemu_strtosz_simple(void)
g_assert_cmpint(err, ==, 0);
g_assert_cmpint(res, ==, 12345);
- /* Note: precision is 53 bits since we're parsing with strtod() */
+ /* Note: If there is no '.', we get full 64 bits of precision */
str = "9007199254740991"; /* 2^53-1 */
err = qemu_strtosz(str, &endptr, &res);
@@ -1987,7 +1994,7 @@ static void test_qemu_strtosz_simple(void)
str = "9007199254740993"; /* 2^53+1 */
err = qemu_strtosz(str, &endptr, &res);
g_assert_cmpint(err, ==, 0);
- g_assert_cmpint(res, ==, 0x20000000000000); /* rounded to 53 bits */
+ g_assert_cmpint(res, ==, 0x20000000000001);
g_assert(endptr == str + 16);
str = "18446744073709549568"; /* 0xfffffffffffff800 (53 msbs set) */
@@ -1999,11 +2006,35 @@ static void test_qemu_strtosz_simple(void)
str = "18446744073709550591"; /* 0xfffffffffffffbff */
err = qemu_strtosz(str, &endptr, &res);
g_assert_cmpint(err, ==, 0);
- g_assert_cmpint(res, ==, 0xfffffffffffff800); /* rounded to 53 bits */
+ g_assert_cmpint(res, ==, 0xfffffffffffffbff);
g_assert(endptr == str + 20);
- /* 0x7ffffffffffffe00..0x7fffffffffffffff get rounded to
- * 0x8000000000000000, thus -ERANGE; see test_qemu_strtosz_erange() */
+ str = "18446744073709551615"; /* 0xffffffffffffffff */
+ err = qemu_strtosz(str, &endptr, &res);
+ g_assert_cmpint(err, ==, 0);
+ g_assert_cmpint(res, ==, 0xffffffffffffffff);
+ g_assert(endptr == str + 20);
+
+}
+
+static void test_qemu_strtosz_hex(void)
+{
+ const char *str;
+ const char *endptr;
+ int err;
+ uint64_t res = 0xbaadf00d;
+
+ str = "0x0";
+ err = qemu_strtosz(str, &endptr, &res);
+ g_assert_cmpint(err, ==, 0);
+ g_assert_cmpint(res, ==, 0);
+ g_assert(endptr == str + 3);
+
+ str = "0xa";
+ err = qemu_strtosz(str, &endptr, &res);
+ g_assert_cmpint(err, ==, 0);
+ g_assert_cmpint(res, ==, 10);
+ g_assert(endptr == str + 3);
}
static void test_qemu_strtosz_units(void)
@@ -2106,6 +2137,21 @@ static void test_qemu_strtosz_invalid(void)
err = qemu_strtosz(str, &endptr, &res);
g_assert_cmpint(err, ==, -EINVAL);
g_assert(endptr == str);
+
+ str = "1.1e5";
+ err = qemu_strtosz(str, &endptr, &res);
+ g_assert_cmpint(err, ==, -EINVAL);
+ g_assert(endptr == str);
I'd add also test with 'E'
+
+ str = "1.1B";
+ err = qemu_strtosz(str, &endptr, &res);
+ g_assert_cmpint(err, ==, -EINVAL);
+ g_assert(endptr == str);
+
+ str = "0x1.8k";
+ err = qemu_strtosz(str, &endptr, &res);
+ g_assert_cmpint(err, ==, -EINVAL);
+ g_assert(endptr == str);
ha this function looks like it should have
const cher *str[] = ["", " \t ", ... "0x1.8k"]
and all cases in a for()... and all other test cases may be ... Oh, I should say myself
"don't refactor everything you see".
}
static void test_qemu_strtosz_trailing(void)
@@ -2145,17 +2191,7 @@ static void test_qemu_strtosz_erange(void)
g_assert_cmpint(err, ==, -ERANGE);
g_assert(endptr == str + 2);
- str = "18446744073709550592"; /* 0xfffffffffffffc00 */
- err = qemu_strtosz(str, &endptr, &res);
- g_assert_cmpint(err, ==, -ERANGE);
- g_assert(endptr == str + 20);
-
- str = "18446744073709551615"; /* 2^64-1 */
- err = qemu_strtosz(str, &endptr, &res);
- g_assert_cmpint(err, ==, -ERANGE);
- g_assert(endptr == str + 20);
-
- str = "18446744073709551616"; /* 2^64 */
+ str = "18446744073709551616"; /* 2^64; see strtosz_simple for 2^64-1 */
err = qemu_strtosz(str, &endptr, &res);
g_assert_cmpint(err, ==, -ERANGE);
g_assert(endptr == str + 20);
@@ -2168,15 +2204,22 @@ static void test_qemu_strtosz_erange(void)
static void test_qemu_strtosz_metric(void)
{
- const char *str = "12345k";
+ const char *str;
int err;
const char *endptr;
uint64_t res = 0xbaadf00d;
+ str = "12345k";
err = qemu_strtosz_metric(str, &endptr, &res);
g_assert_cmpint(err, ==, 0);
g_assert_cmpint(res, ==, 12345000);
g_assert(endptr == str + 6);
+
+ str = "12.345M";
+ err = qemu_strtosz_metric(str, &endptr, &res);
+ g_assert_cmpint(err, ==, 0);
+ g_assert_cmpint(res, ==, 12345000);
+ g_assert(endptr == str + 7);
}
int main(int argc, char **argv)
@@ -2443,6 +2486,8 @@ int main(int argc, char **argv)
g_test_add_func("/cutils/strtosz/simple",
test_qemu_strtosz_simple);
+ g_test_add_func("/cutils/strtosz/hex",
+ test_qemu_strtosz_hex);
g_test_add_func("/cutils/strtosz/units",
test_qemu_strtosz_units);
g_test_add_func("/cutils/strtosz/float",
diff --git a/tests/test-keyval.c b/tests/test-keyval.c
index ee927fe4e427..13be763650b2 100644
--- a/tests/test-keyval.c
+++ b/tests/test-keyval.c
@@ -445,9 +445,9 @@ static void test_keyval_visit_size(void)
visit_end_struct(v, NULL);
visit_free(v);
- /* Note: precision is 53 bits since we're parsing with strtod() */
+ /* Note: full 64 bits of precision */
- /* Around limit of precision: 2^53-1, 2^53, 2^53+1 */
+ /* Around double limit of precision: 2^53-1, 2^53, 2^53+1 */
qdict = keyval_parse("sz1=9007199254740991,"
"sz2=9007199254740992,"
"sz3=9007199254740993",
@@ -460,7 +460,7 @@ static void test_keyval_visit_size(void)
visit_type_size(v, "sz2", &sz, &error_abort);
g_assert_cmphex(sz, ==, 0x20000000000000);
visit_type_size(v, "sz3", &sz, &error_abort);
- g_assert_cmphex(sz, ==, 0x20000000000000);
+ g_assert_cmphex(sz, ==, 0x20000000000001);
visit_check_struct(v, &error_abort);
visit_end_struct(v, NULL);
visit_free(v);
@@ -475,7 +475,7 @@ static void test_keyval_visit_size(void)
visit_type_size(v, "sz1", &sz, &error_abort);
g_assert_cmphex(sz, ==, 0x7ffffffffffffc00);
visit_type_size(v, "sz2", &sz, &error_abort);
- g_assert_cmphex(sz, ==, 0x7ffffffffffffc00);
+ g_assert_cmphex(sz, ==, 0x7ffffffffffffdff);
visit_check_struct(v, &error_abort);
visit_end_struct(v, NULL);
visit_free(v);
@@ -490,14 +490,26 @@ static void test_keyval_visit_size(void)
visit_type_size(v, "sz1", &sz, &error_abort);
g_assert_cmphex(sz, ==, 0xfffffffffffff800);
visit_type_size(v, "sz2", &sz, &error_abort);
- g_assert_cmphex(sz, ==, 0xfffffffffffff800);
+ g_assert_cmphex(sz, ==, 0xfffffffffffffbff);
+ visit_check_struct(v, &error_abort);
+ visit_end_struct(v, NULL);
+ visit_free(v);
+
+ /* Actual limit */
+ qdict = keyval_parse("sz1=18446744073709551615", /* ffffffffffffffff */
+ NULL, NULL, &error_abort);
+ v = qobject_input_visitor_new_keyval(QOBJECT(qdict));
+ qobject_unref(qdict);
+ visit_start_struct(v, NULL, NULL, 0, &error_abort);
+ visit_type_size(v, "sz1", &sz, &error_abort);
+ g_assert_cmphex(sz, ==, 0xffffffffffffffff);
visit_check_struct(v, &error_abort);
visit_end_struct(v, NULL);
visit_free(v);
/* Beyond limits */
qdict = keyval_parse("sz1=-1,"
- "sz2=18446744073709550592", /* fffffffffffffc00 */
+ "sz2=18446744073709551616", /* 2^64 */
NULL, NULL, &error_abort);
v = qobject_input_visitor_new_keyval(QOBJECT(qdict));
qobject_unref(qdict);
diff --git a/tests/test-qemu-opts.c b/tests/test-qemu-opts.c
index 8bbb17b1c726..f79b698e6715 100644
--- a/tests/test-qemu-opts.c
+++ b/tests/test-qemu-opts.c
@@ -654,9 +654,9 @@ static void test_opts_parse_size(void)
g_assert_cmpuint(opts_count(opts), ==, 1);
g_assert_cmpuint(qemu_opt_get_size(opts, "size1", 1), ==, 0);
- /* Note: precision is 53 bits since we're parsing with strtod() */
+ /* Note: full 64 bits of precision */
- /* Around limit of precision: 2^53-1, 2^53, 2^54 */
+ /* Around double limit of precision: 2^53-1, 2^53, 2^53+1 */
opts = qemu_opts_parse(&opts_list_02,
"size1=9007199254740991,"
"size2=9007199254740992,"
@@ -668,7 +668,7 @@ static void test_opts_parse_size(void)
g_assert_cmphex(qemu_opt_get_size(opts, "size2", 1),
==, 0x20000000000000);
g_assert_cmphex(qemu_opt_get_size(opts, "size3", 1),
- ==, 0x20000000000000);
+ ==, 0x20000000000001);
/* Close to signed upper limit 0x7ffffffffffffc00 (53 msbs set) */
should fix comment?
opts = qemu_opts_parse(&opts_list_02,
@@ -679,7 +679,7 @@ static void test_opts_parse_size(void)
g_assert_cmphex(qemu_opt_get_size(opts, "size1", 1),
==, 0x7ffffffffffffc00);
g_assert_cmphex(qemu_opt_get_size(opts, "size2", 1),
- ==, 0x7ffffffffffffc00);
+ ==, 0x7ffffffffffffdff);
/* Close to actual upper limit 0xfffffffffffff800 (53 msbs set) */
and here?
and probably in a previous file
opts = qemu_opts_parse(&opts_list_02,
@@ -690,14 +690,22 @@ static void test_opts_parse_size(void)
g_assert_cmphex(qemu_opt_get_size(opts, "size1", 1),
==, 0xfffffffffffff800);
g_assert_cmphex(qemu_opt_get_size(opts, "size2", 1),
- ==, 0xfffffffffffff800);
+ ==, 0xfffffffffffffbff);
+
+ /* Actual limit */
+ opts = qemu_opts_parse(&opts_list_02,
+ "size1=18446744073709551615", /* ffffffffffffffff */
+ false, &error_abort);
+ g_assert_cmpuint(opts_count(opts), ==, 1);
+ g_assert_cmphex(qemu_opt_get_size(opts, "size1", 1),
+ ==, 0xffffffffffffffff);
/* Beyond limits */
opts = qemu_opts_parse(&opts_list_02, "size1=-1", false, &err);
error_free_or_abort(&err);
g_assert(!opts);
opts = qemu_opts_parse(&opts_list_02,
- "size1=18446744073709550592", /* fffffffffffffc00 */
+ "size1=18446744073709551616", /* 2^64 */
false, &err);
error_free_or_abort(&err);
g_assert(!opts);
Test modifications above all looks OK.
diff --git a/util/cutils.c b/util/cutils.c
index 0b5073b33012..0234763bd70b 100644
--- a/util/cutils.c
+++ b/util/cutils.c
@@ -241,10 +241,21 @@ static int64_t suffix_mul(char suffix, int64_t unit)
}
/*
- * Convert string to bytes, allowing either B/b for bytes, K/k for KB,
- * M/m for MB, G/g for GB or T/t for TB. End pointer will be returned
- * in *end, if not NULL. Return -ERANGE on overflow, and -EINVAL on
- * other error.
+ * Convert size string to bytes.
+ *
+ * Allow either B/b for bytes, K/k for KB, M/m for MB, G/g for GB or
+ * T/t for TB, with scaling based on @unit, and with @default_suffix
+ * implied if no explicit suffix was given.
+ *
+ * The end pointer will be returned in *end, if not NULL. If there is
+ * no fraction, the input can be decimal or hexadecimal; if there is a
+ * fraction, then the input must be decimal and there must be a suffix
+ * (possibly by @default_suffix) larger than Byte, and the fractional
+ * portion may suffer from precision loss or rounding. The input must
+ * be positive.
+ *
+ * Return -ERANGE on overflow (with *@end advanced), and -EINVAL on
+ * other error (with *@end left unchanged).
*/
static int do_strtosz(const char *nptr, const char **end,
const char default_suffix, int64_t unit,
@@ -253,40 +264,66 @@ static int do_strtosz(const char *nptr, const char **end,
int retval;
const char *endptr;
unsigned char c;
- int mul_required = 0;
- double val, mul, integral, fraction;
+ bool mul_required = false;
+ uint64_t val;
+ int64_t mul;
+ double fraction = 0.0;
- retval = qemu_strtod_finite(nptr, &endptr, &val);
+ /* Parse integral portion as decimal. */
+ retval = qemu_strtou64(nptr, &endptr, 10, &val);
if (retval) {
goto out;
}
- fraction = modf(val, &integral);
- if (fraction != 0) {
- mul_required = 1;
+ if (strchr(nptr, '-') != NULL) {
+ retval = -ERANGE;
+ goto out;
+ }
Hmm, I have a question: does do_strtosz assumes that the whole nptr string is a
number?
If yes, then I don't understand what the matter of **end OUT-argument.
If not, this if() is wrong, as you'll redject parsing first number of "123425 -
2323" string..
+ if (val == 0 && (*endptr == 'x' || *endptr == 'X')) {
+ /* Input looks like hex, reparse, and insist on no fraction. */
+ retval = qemu_strtou64(nptr, &endptr, 16, &val);
+ if (retval) {
+ goto out;
+ }
+ if (*endptr == '.') {
+ endptr = nptr;
+ retval = -EINVAL;
+ goto out;
+ }
+ } else if (*endptr == '.') {
+ /* Input is fractional, insist on 0 <= fraction < 1, with no exponent
*/
+ retval = qemu_strtod_finite(endptr, &endptr, &fraction);
+ if (retval) {
+ endptr = nptr;
+ goto out;
+ }
+ if (fraction >= 1.0 || memchr(nptr, 'e', endptr - nptr)
+ || memchr(nptr, 'E', endptr - nptr)) {
+ endptr = nptr;
+ retval = -EINVAL;
+ goto out;
+ }
+ if (fraction != 0) {
+ mul_required = true;
+ }
}
c = *endptr;
mul = suffix_mul(c, unit);
- if (mul >= 0) {
+ if (mul > 0) {
endptr++;
} else {
mul = suffix_mul(default_suffix, unit);
- assert(mul >= 0);
+ assert(mul > 0);
}
if (mul == 1 && mul_required) {
+ endptr = nptr;
retval = -EINVAL;
goto out;
}
- /*
- * Values near UINT64_MAX overflow to 2**64 when converting to double
- * precision. Compare against the maximum representable double precision
- * value below 2**64, computed as "the next value after 2**64 (0x1p64) in
- * the direction of 0".
- */
- if ((val * mul > nextafter(0x1p64, 0)) || val < 0) {
+ if (val > UINT64_MAX / mul) {
retval = -ERANGE;
goto out;
}
- *result = val * mul;
+ *result = val * mul + (uint64_t) (fraction * mul);
retval = 0;
out:
diff --git a/tests/qemu-iotests/049.out b/tests/qemu-iotests/049.out
index b1d8fd9107ef..f38d3ccd5978 100644
--- a/tests/qemu-iotests/049.out
+++ b/tests/qemu-iotests/049.out
@@ -98,10 +98,13 @@ qemu-img create -f qcow2 -o size=-1024 TEST_DIR/t.qcow2
qemu-img: TEST_DIR/t.qcow2: Value '-1024' is out of range for parameter 'size'
qemu-img create -f qcow2 TEST_DIR/t.qcow2 -- -1k
-qemu-img: Invalid image size specified. Must be between 0 and
9223372036854775807.
+qemu-img: Invalid image size specified. You may use k, M, G, T, P or E
suffixes for
+qemu-img: kilobytes, megabytes, gigabytes, terabytes, petabytes and exabytes.
qemu-img create -f qcow2 -o size=-1k TEST_DIR/t.qcow2
-qemu-img: TEST_DIR/t.qcow2: Value '-1k' is out of range for parameter 'size'
+qemu-img: TEST_DIR/t.qcow2: Parameter 'size' expects a non-negative number
below 2^64
+Optional suffix k, M, G, T, P or E means kilo-, mega-, giga-, tera-, peta-
+and exabytes, respectively.
qemu-img create -f qcow2 TEST_DIR/t.qcow2 -- 1kilobyte
qemu-img: Invalid image size specified. You may use k, M, G, T, P or E
suffixes for
--
Best regards,
Vladimir
