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Message-Id: <20250209-nolibc-scanf-v2-1-c29dea32f1cd@weissschuh.net>
Date: Sun, 09 Feb 2025 21:27:12 +0100
From: Thomas Weißschuh <linux@...ssschuh.net>
To: Willy Tarreau <w@....eu>, Shuah Khan <shuah@...nel.org>
Cc: linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org,
Thomas Weißschuh <linux@...ssschuh.net>
Subject: [PATCH v2 1/2] tools/nolibc: add support for [v]sscanf()
These functions are used often, also in selftests.
sscanf() itself is also used by kselftest.h itself.
The implementation is limited and only supports numeric arguments.
Signed-off-by: Thomas Weißschuh <linux@...ssschuh.net>
---
tools/include/nolibc/stdio.h | 98 ++++++++++++++++++++++++++++
tools/testing/selftests/nolibc/nolibc-test.c | 68 +++++++++++++++++++
2 files changed, 166 insertions(+)
diff --git a/tools/include/nolibc/stdio.h b/tools/include/nolibc/stdio.h
index 3892034198dd566d21a5cc0a9f67cf097d428393..a403351dbf6098ac8292b9589ed8a054b4c5669f 100644
--- a/tools/include/nolibc/stdio.h
+++ b/tools/include/nolibc/stdio.h
@@ -349,6 +349,104 @@ int printf(const char *fmt, ...)
return ret;
}
+static __attribute__((unused))
+int vsscanf(const char *str, const char *format, va_list args)
+{
+ uintmax_t uval;
+ intmax_t ival;
+ int base;
+ char *endptr;
+ int matches;
+ int lpref;
+
+ matches = 0;
+
+ while (1) {
+ if (*format == '%') {
+ /* start of pattern */
+ lpref = 0;
+ format++;
+
+ if (*format == 'l') {
+ /* same as in printf() */
+ lpref = 1;
+ format++;
+ if (*format == 'l') {
+ lpref = 2;
+ format++;
+ }
+ }
+
+ if (*format == '%') {
+ /* literal % */
+ if ('%' != *str)
+ goto done;
+ str++;
+ format++;
+ continue;
+ } else if (*format == 'd') {
+ ival = strtoll(str, &endptr, 10);
+ if (lpref == 0)
+ *va_arg(args, int *) = ival;
+ else if (lpref == 1)
+ *va_arg(args, long *) = ival;
+ else if (lpref == 2)
+ *va_arg(args, long long *) = ival;
+ } else if (*format == 'u' || *format == 'x' || *format == 'X') {
+ base = *format == 'u' ? 10 : 16;
+ uval = strtoull(str, &endptr, base);
+ if (lpref == 0)
+ *va_arg(args, unsigned int *) = uval;
+ else if (lpref == 1)
+ *va_arg(args, unsigned long *) = uval;
+ else if (lpref == 2)
+ *va_arg(args, unsigned long long *) = uval;
+ } else if (*format == 'p') {
+ *va_arg(args, void **) = (void *)strtoul(str, &endptr, 16);
+ } else {
+ SET_ERRNO(EILSEQ);
+ goto done;
+ }
+
+ format++;
+ str = endptr;
+ matches++;
+
+ } else if (*format == '\0') {
+ goto done;
+ } else if (isspace(*format)) {
+ /* skip spaces in format and str */
+ while (isspace(*format))
+ format++;
+ while (isspace(*str))
+ str++;
+ } else if (*format == *str) {
+ /* literal match */
+ format++;
+ str++;
+ } else {
+ if (!matches)
+ matches = EOF;
+ goto done;
+ }
+ }
+
+done:
+ return matches;
+}
+
+static __attribute__((unused, format(scanf, 2, 3)))
+int sscanf(const char *str, const char *format, ...)
+{
+ va_list args;
+ int ret;
+
+ va_start(args, format);
+ ret = vsscanf(str, format, args);
+ va_end(args);
+ return ret;
+}
+
static __attribute__((unused))
void perror(const char *msg)
{
diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
index 798fbdcd3ff8c36b514feb3fa1c7b8d7701cccd7..81e942c7d1684a7dd59af0b05c8330378532ecc1 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -1325,6 +1325,73 @@ static int expect_vfprintf(int llen, int c, const char *expected, const char *fm
return ret;
}
+static int test_scanf(void)
+{
+ unsigned long long ull;
+ unsigned long ul;
+ unsigned int u;
+ long long ll;
+ long l;
+ void *p;
+ int i;
+
+ /* return __LINE__ to point to the specific failure */
+
+ /* test EOF */
+ if (sscanf("", "foo") != EOF)
+ return __LINE__;
+
+ /* test simple literal without placeholder */
+ if (sscanf("foo", "foo") != 0)
+ return __LINE__;
+
+ /* test single placeholder */
+ if (sscanf("123", "%d", &i) != 1)
+ return __LINE__;
+
+ if (i != 123)
+ return __LINE__;
+
+ /* test multiple place holders and separators */
+ if (sscanf("a123b456c0x90", "a%db%uc%p", &i, &u, &p) != 3)
+ return __LINE__;
+
+ if (i != 123)
+ return __LINE__;
+
+ if (u != 456)
+ return __LINE__;
+
+ if (p != (void *)0x90)
+ return __LINE__;
+
+ /* test space handling */
+ if (sscanf("a b1", "a b%d", &i) != 1)
+ return __LINE__;
+
+ if (i != 1)
+ return __LINE__;
+
+ /* test literal percent */
+ if (sscanf("a%1", "a%%%d", &i) != 1)
+ return __LINE__;
+
+ if (i != 1)
+ return __LINE__;
+
+ /* test stdint.h types */
+ if (sscanf("1|2|3|4|5|6",
+ "%d|%ld|%lld|%u|%lu|%llu",
+ &i, &l, &ll, &u, &ul, &ull) != 6)
+ return __LINE__;
+
+ if (i != 1 || l != 2 || ll != 3 ||
+ u != 4 || ul != 5 || ull != 6)
+ return __LINE__;
+
+ return 0;
+}
+
static int run_vfprintf(int min, int max)
{
int test;
@@ -1346,6 +1413,7 @@ static int run_vfprintf(int min, int max)
CASE_TEST(char); EXPECT_VFPRINTF(1, "c", "%c", 'c'); break;
CASE_TEST(hex); EXPECT_VFPRINTF(1, "f", "%x", 0xf); break;
CASE_TEST(pointer); EXPECT_VFPRINTF(3, "0x1", "%p", (void *) 0x1); break;
+ CASE_TEST(scanf); EXPECT_ZR(1, test_scanf()); break;
case __LINE__:
return ret; /* must be last */
/* note: do not set any defaults so as to permit holes above */
--
2.48.1
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