Commit 533dcaf3 authored by Nicolas Pitre's avatar Nicolas Pitre Committed by Anas Nashif
Browse files

lib/os/cbprintf_nano.c: avoid sign extension on unsigned formats 



There might be a sign extension when a long is promoted to
int_value_type and the former type is smaller than the later.
This produces the wrong output if the specified format is unsigned.

Let's avoid this problem by handling signed and unsigned cases
explicitly. When the type already matches int_value_type then the
compiler is smart enough to recognize the redundancy and removes
unneeded duplications automatically, meaning that the code will stay
small when code size matters.

A similar issue also existed in the restricted %llu case.
The fix is the same as above.

Those fixes exposed wrong results in the printk.c test with %llx
so fix that as well.

Signed-off-by: default avatarNicolas Pitre <npitre@baylibre.com>
parent ea55ebfa

lib/os/cbprintf_nano.c

+41 −12
Original line number Diff line number Diff line
@@ -174,20 +174,40 @@ start: 
			uint_value_type d;



			if (length_mod == 'z') {

				if (*fmt == 'u') {

					d = va_arg(ap, size_t);

				} else {

					d = va_arg(ap, ssize_t);

				}

			} else if (length_mod == 'l') {

				if (*fmt == 'u') {

					d = va_arg(ap, unsigned long);

				} else {

					d = va_arg(ap, long);

				}

			} else if (length_mod == 'L') {

				if (*fmt == 'u') {

					unsigned long long llu =

						va_arg(ap, unsigned long long);



					if (llu != (uint_value_type) llu) {

						data = "ERR";

						data_len = 3;

						precision = 0;

						break;

					}

					d = (uint_value_type) llu;

				} else {

					long long lld = va_arg(ap, long long);



				if (sizeof(int_value_type) < 8U &&

				    lld != (int_value_type) lld) {

					if (lld != (int_value_type) lld) {

						data = "ERR";

						data_len = 3;

						precision = 0;

						break;

					}

				d = (uint_value_type) lld;

					d = (int_value_type) lld;

				}

			} else if (*fmt == 'u') {

				d = va_arg(ap, unsigned int);

			} else {
@@ -229,7 +249,16 @@ start: 
			} else if (length_mod == 'l') {

				x = va_arg(ap, unsigned long);

			} else if (length_mod == 'L') {

				x = va_arg(ap, unsigned long long);

				unsigned long long llx =

					va_arg(ap, unsigned long long);



				if (llx != (uint_value_type) llx) {

					data = "ERR";

					data_len = 3;

					precision = 0;

					break;

				}

				x = (uint_value_type) llx;

			} else {

				x = va_arg(ap, unsigned int);

			}

tests/kernel/common/src/printk.c

+1 −1
Original line number Diff line number Diff line
@@ -51,7 +51,7 @@ char *expected = "22 113 10000 32768 40000 22\n" 
		 "42 42   42       42\n"

		 "42 42 0042 00000042\n"

		 "255     42    abcdef        42\n"

		 "ERR -1 4294967295 ffffffff\n"

		 "ERR -1 ERR ERR\n"

		 "0xcafebabe 0xbeef 0x2a\n"

;

#endif

tests/unit/cbprintf/main.c

+8 −7
Original line number Diff line number Diff line
@@ -502,6 +502,7 @@ static void test_d_length(void) 
	int max = 1876543210;

	long long svll = 123LL << 48;

	long long svll2 = -2LL;

	unsigned long long uvll = 4000000000LLU;

	int rc;



	TEST_PRF(&rc, "%d/%d", min, max);
@@ -518,22 +519,22 @@ static void test_d_length(void) 
		PRF_CHECK("46/-22", rc);

	}



	TEST_PRF(&rc, "%ld/%ld", (long)min, (long)max);

	TEST_PRF(&rc, "%ld/%ld/%lu/", (long)min, (long)max, 4000000000UL);

	if (IS_ENABLED(CONFIG_CBPRINTF_FULL_INTEGRAL)

	    || (sizeof(long) <= 4)

	    || IS_ENABLED(CONFIG_CBPRINTF_NANO)) {

		PRF_CHECK("-1234567890/1876543210", rc);

		PRF_CHECK("-1234567890/1876543210/4000000000/", rc);

	} else {

		PRF_CHECK("%ld/%ld", rc);

		PRF_CHECK("%ld/%ld/%lu/", rc);

	}



	TEST_PRF(&rc, "/%lld/%lld/%lld/", svll, -svll, svll2);

	TEST_PRF(&rc, "/%lld/%lld/%lld/%llu/", svll, -svll, svll2, uvll);

	if (IS_ENABLED(CONFIG_CBPRINTF_FULL_INTEGRAL)) {

		PRF_CHECK("/34621422135410688/-34621422135410688/-2/", rc);

		PRF_CHECK("/34621422135410688/-34621422135410688/-2/4000000000/", rc);

	} else if (IS_ENABLED(CONFIG_CBPRINTF_COMPLETE)) {

		PRF_CHECK("/%lld/%lld/%lld/", rc);

		PRF_CHECK("/%lld/%lld/%lld/%llu/", rc);

	} else if (IS_ENABLED(CONFIG_CBPRINTF_NANO)) {

		PRF_CHECK("/ERR/ERR/-2/", rc);

		PRF_CHECK("/ERR/ERR/-2/4000000000/", rc);

	} else {

		zassert_true(false, "Missed case!");

	}

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