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tools/nolibc: add support for [v]sscanf()

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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.

Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/r/20250209-nolibc-scanf-v2-1-c29dea32f1cd@weissschuh.net
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
This commit is contained in:
Thomas Weißschuh 2025-02-09 21:27:12 +01:00
parent 9c812b01f1
commit 22edf1f8d4
2 changed files with 166 additions and 0 deletions
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98
tools/include/nolibc/stdio.h
View File

@ -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)
{

68
tools/testing/selftests/nolibc/nolibc-test.c
View File

@ -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 */