xref: /linux/lib/test_scanf.c (revision 53b0fe36ab7c6eb3ce8ca711e636806649273463)

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Test cases for sscanf facility.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/bitops.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/overflow.h>
#include <linux/printk.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/string.h>

#include "../tools/testing/selftests/kselftest_module.h"

#define BUF_SIZE 1024

KSTM_MODULE_GLOBALS();
static char *test_buffer __initdata;
static char *fmt_buffer __initdata;
static struct rnd_state rnd_state __initdata;

typedef int (*check_fn)(const void *check_data, const char *string,
			const char *fmt, int n_args, va_list ap);

static void __scanf(4, 6) __init
_test(check_fn fn, const void *check_data, const char *string, const char *fmt,
	int n_args, ...)
{
	va_list ap, ap_copy;
	int ret;

	total_tests++;

	va_start(ap, n_args);
	va_copy(ap_copy, ap);
	ret = vsscanf(string, fmt, ap_copy);
	va_end(ap_copy);

	if (ret != n_args) {
		pr_warn("vsscanf(\"%s\", \"%s\", ...) returned %d expected %d\n",
			string, fmt, ret, n_args);
		goto fail;
	}

	ret = (*fn)(check_data, string, fmt, n_args, ap);
	if (ret)
		goto fail;

	va_end(ap);

	return;

fail:
	failed_tests++;
	va_end(ap);
}

#define _check_numbers_template(arg_fmt, expect, str, fmt, n_args, ap)		\
do {										\
	pr_debug("\"%s\", \"%s\" ->\n", str, fmt);				\
	for (; n_args > 0; n_args--, expect++) {				\
		typeof(*expect) got = *va_arg(ap, typeof(expect));		\
		pr_debug("\t" arg_fmt "\n", got);				\
		if (got != *expect) {						\
			pr_warn("vsscanf(\"%s\", \"%s\", ...) expected " arg_fmt " got " arg_fmt "\n", \
				str, fmt, *expect, got);			\
			return 1;						\
		}								\
	}									\
	return 0;								\
} while (0)

static int __init check_ull(const void *check_data, const char *string,
			    const char *fmt, int n_args, va_list ap)
{
	const unsigned long long *pval = check_data;

	_check_numbers_template("%llu", pval, string, fmt, n_args, ap);
}

static int __init check_ll(const void *check_data, const char *string,
			   const char *fmt, int n_args, va_list ap)
{
	const long long *pval = check_data;

	_check_numbers_template("%lld", pval, string, fmt, n_args, ap);
}

static int __init check_ulong(const void *check_data, const char *string,
			   const char *fmt, int n_args, va_list ap)
{
	const unsigned long *pval = check_data;

	_check_numbers_template("%lu", pval, string, fmt, n_args, ap);
}

static int __init check_long(const void *check_data, const char *string,
			  const char *fmt, int n_args, va_list ap)
{
	const long *pval = check_data;

	_check_numbers_template("%ld", pval, string, fmt, n_args, ap);
}

static int __init check_uint(const void *check_data, const char *string,
			     const char *fmt, int n_args, va_list ap)
{
	const unsigned int *pval = check_data;

	_check_numbers_template("%u", pval, string, fmt, n_args, ap);
}

static int __init check_int(const void *check_data, const char *string,
			    const char *fmt, int n_args, va_list ap)
{
	const int *pval = check_data;

	_check_numbers_template("%d", pval, string, fmt, n_args, ap);
}

static int __init check_ushort(const void *check_data, const char *string,
			       const char *fmt, int n_args, va_list ap)
{
	const unsigned short *pval = check_data;

	_check_numbers_template("%hu", pval, string, fmt, n_args, ap);
}

static int __init check_short(const void *check_data, const char *string,
			       const char *fmt, int n_args, va_list ap)
{
	const short *pval = check_data;

	_check_numbers_template("%hd", pval, string, fmt, n_args, ap);
}

static int __init check_uchar(const void *check_data, const char *string,
			       const char *fmt, int n_args, va_list ap)
{
	const unsigned char *pval = check_data;

	_check_numbers_template("%hhu", pval, string, fmt, n_args, ap);
}

static int __init check_char(const void *check_data, const char *string,
			       const char *fmt, int n_args, va_list ap)
{
	const signed char *pval = check_data;

	_check_numbers_template("%hhd", pval, string, fmt, n_args, ap);
}

/* Selection of interesting numbers to test, copied from test-kstrtox.c */
static const unsigned long long numbers[] __initconst = {
	0x0ULL,
	0x1ULL,
	0x7fULL,
	0x80ULL,
	0x81ULL,
	0xffULL,
	0x100ULL,
	0x101ULL,
	0x7fffULL,
	0x8000ULL,
	0x8001ULL,
	0xffffULL,
	0x10000ULL,
	0x10001ULL,
	0x7fffffffULL,
	0x80000000ULL,
	0x80000001ULL,
	0xffffffffULL,
	0x100000000ULL,
	0x100000001ULL,
	0x7fffffffffffffffULL,
	0x8000000000000000ULL,
	0x8000000000000001ULL,
	0xfffffffffffffffeULL,
	0xffffffffffffffffULL,
};

#define value_representable_in_type(T, val)					 \
(is_signed_type(T)								 \
	? ((long long)(val) >= type_min(T)) && ((long long)(val) <= type_max(T)) \
	: ((unsigned long long)(val) <= type_max(T)))


#define test_one_number(T, gen_fmt, scan_fmt, val, fn)			\
do {									\
	const T expect_val = (T)(val);					\
	T result = ~expect_val; /* should be overwritten */		\
									\
	snprintf(test_buffer, BUF_SIZE, gen_fmt, expect_val);		\
	_test(fn, &expect_val, test_buffer, "%" scan_fmt, 1, &result);	\
} while (0)

#define simple_numbers_loop(T, gen_fmt, scan_fmt, fn)			\
do {									\
	int i;								\
									\
	for (i = 0; i < ARRAY_SIZE(numbers); i++) {			\
		if (value_representable_in_type(T, numbers[i]))		\
			test_one_number(T, gen_fmt, scan_fmt,		\
					numbers[i], fn);		\
									\
		if (value_representable_in_type(T, -numbers[i]))	\
			test_one_number(T, gen_fmt, scan_fmt,		\
					-numbers[i], fn);		\
	}								\
} while (0)

static void __init numbers_simple(void)
{
	simple_numbers_loop(unsigned long long,	"%llu",	  "llu", check_ull);
	simple_numbers_loop(long long,		"%lld",	  "lld", check_ll);
	simple_numbers_loop(long long,		"%lld",	  "lli", check_ll);
	simple_numbers_loop(unsigned long long,	"%llx",	  "llx", check_ull);
	simple_numbers_loop(long long,		"%llx",	  "llx", check_ll);
	simple_numbers_loop(long long,		"0x%llx", "lli", check_ll);
	simple_numbers_loop(unsigned long long, "0x%llx", "llx", check_ull);
	simple_numbers_loop(long long,		"0x%llx", "llx", check_ll);

	simple_numbers_loop(unsigned long,	"%lu",	  "lu", check_ulong);
	simple_numbers_loop(long,		"%ld",	  "ld", check_long);
	simple_numbers_loop(long,		"%ld",	  "li", check_long);
	simple_numbers_loop(unsigned long,	"%lx",	  "lx", check_ulong);
	simple_numbers_loop(long,		"%lx",	  "lx", check_long);
	simple_numbers_loop(long,		"0x%lx",  "li", check_long);
	simple_numbers_loop(unsigned long,	"0x%lx",  "lx", check_ulong);
	simple_numbers_loop(long,		"0x%lx",  "lx", check_long);

	simple_numbers_loop(unsigned int,	"%u",	  "u", check_uint);
	simple_numbers_loop(int,		"%d",	  "d", check_int);
	simple_numbers_loop(int,		"%d",	  "i", check_int);
	simple_numbers_loop(unsigned int,	"%x",	  "x", check_uint);
	simple_numbers_loop(int,		"%x",	  "x", check_int);
	simple_numbers_loop(int,		"0x%x",   "i", check_int);
	simple_numbers_loop(unsigned int,	"0x%x",   "x", check_uint);
	simple_numbers_loop(int,		"0x%x",   "x", check_int);

	simple_numbers_loop(unsigned short,	"%hu",	  "hu", check_ushort);
	simple_numbers_loop(short,		"%hd",	  "hd", check_short);
	simple_numbers_loop(short,		"%hd",	  "hi", check_short);
	simple_numbers_loop(unsigned short,	"%hx",	  "hx", check_ushort);
	simple_numbers_loop(short,		"%hx",	  "hx", check_short);
	simple_numbers_loop(short,		"0x%hx",  "hi", check_short);
	simple_numbers_loop(unsigned short,	"0x%hx",  "hx", check_ushort);
	simple_numbers_loop(short,		"0x%hx",  "hx", check_short);

	simple_numbers_loop(unsigned char,	"%hhu",	  "hhu", check_uchar);
	simple_numbers_loop(signed char,	"%hhd",	  "hhd", check_char);
	simple_numbers_loop(signed char,	"%hhd",	  "hhi", check_char);
	simple_numbers_loop(unsigned char,	"%hhx",	  "hhx", check_uchar);
	simple_numbers_loop(signed char,	"%hhx",	  "hhx", check_char);
	simple_numbers_loop(signed char,	"0x%hhx", "hhi", check_char);
	simple_numbers_loop(unsigned char,	"0x%hhx", "hhx", check_uchar);
	simple_numbers_loop(signed char,	"0x%hhx", "hhx", check_char);
}

/*
 * This gives a better variety of number "lengths" in a small sample than
 * the raw prandom*() functions (Not mathematically rigorous!!).
 * Variabilty of length and value is more important than perfect randomness.
 */
static u32 __init next_test_random(u32 max_bits)
{
	u32 n_bits = hweight32(prandom_u32_state(&rnd_state)) % (max_bits + 1);

	return prandom_u32_state(&rnd_state) & (UINT_MAX >> (32 - n_bits));
}

static unsigned long long __init next_test_random_ull(void)
{
	u32 rand1 = prandom_u32_state(&rnd_state);
	u32 n_bits = (hweight32(rand1) * 3) % 64;
	u64 val = (u64)prandom_u32_state(&rnd_state) * rand1;

	return val & (ULLONG_MAX >> (64 - n_bits));
}

#define random_for_type(T)				\
	((T)(sizeof(T) <= sizeof(u32)			\
		? next_test_random(BITS_PER_TYPE(T))	\
		: next_test_random_ull()))

/*
 * Define a pattern of negative and positive numbers to ensure we get
 * some of both within the small number of samples in a test string.
 */
#define NEGATIVES_PATTERN 0x3246	/* 00110010 01000110 */

#define fill_random_array(arr)							\
do {										\
	unsigned int neg_pattern = NEGATIVES_PATTERN;				\
	int i;									\
										\
	for (i = 0; i < ARRAY_SIZE(arr); i++, neg_pattern >>= 1) {		\
		(arr)[i] = random_for_type(typeof((arr)[0]));			\
		if (is_signed_type(typeof((arr)[0])) && (neg_pattern & 1))	\
			(arr)[i] = -(arr)[i];					\
	}									\
} while (0)

/*
 * Convenience wrapper around snprintf() to append at buf_pos in buf,
 * updating buf_pos and returning the number of characters appended.
 * On error buf_pos is not changed and return value is 0.
 */
static int __init __printf(4, 5)
append_fmt(char *buf, int *buf_pos, int buf_len, const char *val_fmt, ...)
{
	va_list ap;
	int field_len;

	va_start(ap, val_fmt);
	field_len = vsnprintf(buf + *buf_pos, buf_len - *buf_pos, val_fmt, ap);
	va_end(ap);

	if (field_len < 0)
		field_len = 0;

	*buf_pos += field_len;

	return field_len;
}

/*
 * Convenience function to append the field delimiter string
 * to both the value string and format string buffers.
 */
static void __init append_delim(char *str_buf, int *str_buf_pos, int str_buf_len,
				char *fmt_buf, int *fmt_buf_pos, int fmt_buf_len,
				const char *delim_str)
{
	append_fmt(str_buf, str_buf_pos, str_buf_len, delim_str);
	append_fmt(fmt_buf, fmt_buf_pos, fmt_buf_len, delim_str);
}

#define test_array_8(fn, check_data, string, fmt, arr)				\
do {										\
	BUILD_BUG_ON(ARRAY_SIZE(arr) != 8);					\
	_test(fn, check_data, string, fmt, 8,					\
		&(arr)[0], &(arr)[1], &(arr)[2], &(arr)[3],			\
		&(arr)[4], &(arr)[5], &(arr)[6], &(arr)[7]);			\
} while (0)

#define numbers_list_8(T, gen_fmt, field_sep, scan_fmt, fn)			\
do {										\
	int i, pos = 0, fmt_pos = 0;						\
	T expect[8], result[8];							\
										\
	fill_random_array(expect);						\
										\
	for (i = 0; i < ARRAY_SIZE(expect); i++) {				\
		if (i != 0)							\
			append_delim(test_buffer, &pos, BUF_SIZE,		\
				     fmt_buffer, &fmt_pos, BUF_SIZE,		\
				     field_sep);				\
										\
		append_fmt(test_buffer, &pos, BUF_SIZE, gen_fmt, expect[i]);	\
		append_fmt(fmt_buffer, &fmt_pos, BUF_SIZE, "%%%s", scan_fmt);	\
	}									\
										\
	test_array_8(fn, expect, test_buffer, fmt_buffer, result);		\
} while (0)

#define numbers_list_fix_width(T, gen_fmt, field_sep, width, scan_fmt, fn)	\
do {										\
	char full_fmt[16];							\
										\
	snprintf(full_fmt, sizeof(full_fmt), "%u%s", width, scan_fmt);		\
	numbers_list_8(T, gen_fmt, field_sep, full_fmt, fn);			\
} while (0)

#define numbers_list_val_width(T, gen_fmt, field_sep, scan_fmt, fn)		\
do {										\
	int i, val_len, pos = 0, fmt_pos = 0;					\
	T expect[8], result[8];							\
										\
	fill_random_array(expect);						\
										\
	for (i = 0; i < ARRAY_SIZE(expect); i++) {				\
		if (i != 0)							\
			append_delim(test_buffer, &pos, BUF_SIZE,		\
				     fmt_buffer, &fmt_pos, BUF_SIZE, field_sep);\
										\
		val_len = append_fmt(test_buffer, &pos, BUF_SIZE, gen_fmt,	\
				     expect[i]);				\
		append_fmt(fmt_buffer, &fmt_pos, BUF_SIZE,			\
			   "%%%u%s", val_len, scan_fmt);			\
	}									\
										\
	test_array_8(fn, expect, test_buffer, fmt_buffer, result);		\
} while (0)

static void __init numbers_list(const char *delim)
{
	numbers_list_8(unsigned long long, "%llu",   delim, "llu", check_ull);
	numbers_list_8(long long,	   "%lld",   delim, "lld", check_ll);
	numbers_list_8(long long,	   "%lld",   delim, "lli", check_ll);
	numbers_list_8(unsigned long long, "%llx",   delim, "llx", check_ull);
	numbers_list_8(unsigned long long, "0x%llx", delim, "llx", check_ull);
	numbers_list_8(long long,	   "0x%llx", delim, "lli", check_ll);

	numbers_list_8(unsigned long,	   "%lu",    delim, "lu", check_ulong);
	numbers_list_8(long,		   "%ld",    delim, "ld", check_long);
	numbers_list_8(long,		   "%ld",    delim, "li", check_long);
	numbers_list_8(unsigned long,	   "%lx",    delim, "lx", check_ulong);
	numbers_list_8(unsigned long,	   "0x%lx",  delim, "lx", check_ulong);
	numbers_list_8(long,		   "0x%lx",  delim, "li", check_long);

	numbers_list_8(unsigned int,	   "%u",     delim, "u", check_uint);
	numbers_list_8(int,		   "%d",     delim, "d", check_int);
	numbers_list_8(int,		   "%d",     delim, "i", check_int);
	numbers_list_8(unsigned int,	   "%x",     delim, "x", check_uint);
	numbers_list_8(unsigned int,	   "0x%x",   delim, "x", check_uint);
	numbers_list_8(int,		   "0x%x",   delim, "i", check_int);

	numbers_list_8(unsigned short,	   "%hu",    delim, "hu", check_ushort);
	numbers_list_8(short,		   "%hd",    delim, "hd", check_short);
	numbers_list_8(short,		   "%hd",    delim, "hi", check_short);
	numbers_list_8(unsigned short,	   "%hx",    delim, "hx", check_ushort);
	numbers_list_8(unsigned short,	   "0x%hx",  delim, "hx", check_ushort);
	numbers_list_8(short,		   "0x%hx",  delim, "hi", check_short);

	numbers_list_8(unsigned char,	   "%hhu",   delim, "hhu", check_uchar);
	numbers_list_8(signed char,	   "%hhd",   delim, "hhd", check_char);
	numbers_list_8(signed char,	   "%hhd",   delim, "hhi", check_char);
	numbers_list_8(unsigned char,	   "%hhx",   delim, "hhx", check_uchar);
	numbers_list_8(unsigned char,	   "0x%hhx", delim, "hhx", check_uchar);
	numbers_list_8(signed char,	   "0x%hhx", delim, "hhi", check_char);
}

/*
 * List of numbers separated by delim. Each field width specifier is the
 * maximum possible digits for the given type and base.
 */
static void __init numbers_list_field_width_typemax(const char *delim)
{
	numbers_list_fix_width(unsigned long long, "%llu",   delim, 20, "llu", check_ull);
	numbers_list_fix_width(long long,	   "%lld",   delim, 20, "lld", check_ll);
	numbers_list_fix_width(long long,	   "%lld",   delim, 20, "lli", check_ll);
	numbers_list_fix_width(unsigned long long, "%llx",   delim, 16, "llx", check_ull);
	numbers_list_fix_width(unsigned long long, "0x%llx", delim, 18, "llx", check_ull);
	numbers_list_fix_width(long long,	   "0x%llx", delim, 18, "lli", check_ll);

#if BITS_PER_LONG == 64
	numbers_list_fix_width(unsigned long,	"%lu",	     delim, 20, "lu", check_ulong);
	numbers_list_fix_width(long,		"%ld",	     delim, 20, "ld", check_long);
	numbers_list_fix_width(long,		"%ld",	     delim, 20, "li", check_long);
	numbers_list_fix_width(unsigned long,	"%lx",	     delim, 16, "lx", check_ulong);
	numbers_list_fix_width(unsigned long,	"0x%lx",     delim, 18, "lx", check_ulong);
	numbers_list_fix_width(long,		"0x%lx",     delim, 18, "li", check_long);
#else
	numbers_list_fix_width(unsigned long,	"%lu",	     delim, 10, "lu", check_ulong);
	numbers_list_fix_width(long,		"%ld",	     delim, 11, "ld", check_long);
	numbers_list_fix_width(long,		"%ld",	     delim, 11, "li", check_long);
	numbers_list_fix_width(unsigned long,	"%lx",	     delim, 8,  "lx", check_ulong);
	numbers_list_fix_width(unsigned long,	"0x%lx",     delim, 10, "lx", check_ulong);
	numbers_list_fix_width(long,		"0x%lx",     delim, 10, "li", check_long);
#endif

	numbers_list_fix_width(unsigned int,	"%u",	     delim, 10, "u", check_uint);
	numbers_list_fix_width(int,		"%d",	     delim, 11, "d", check_int);
	numbers_list_fix_width(int,		"%d",	     delim, 11, "i", check_int);
	numbers_list_fix_width(unsigned int,	"%x",	     delim, 8,  "x", check_uint);
	numbers_list_fix_width(unsigned int,	"0x%x",	     delim, 10, "x", check_uint);
	numbers_list_fix_width(int,		"0x%x",	     delim, 10, "i", check_int);

	numbers_list_fix_width(unsigned short,	"%hu",	     delim, 5, "hu", check_ushort);
	numbers_list_fix_width(short,		"%hd",	     delim, 6, "hd", check_short);
	numbers_list_fix_width(short,		"%hd",	     delim, 6, "hi", check_short);
	numbers_list_fix_width(unsigned short,	"%hx",	     delim, 4, "hx", check_ushort);
	numbers_list_fix_width(unsigned short,	"0x%hx",     delim, 6, "hx", check_ushort);
	numbers_list_fix_width(short,		"0x%hx",     delim, 6, "hi", check_short);

	numbers_list_fix_width(unsigned char,	"%hhu",	     delim, 3, "hhu", check_uchar);
	numbers_list_fix_width(signed char,	"%hhd",	     delim, 4, "hhd", check_char);
	numbers_list_fix_width(signed char,	"%hhd",	     delim, 4, "hhi", check_char);
	numbers_list_fix_width(unsigned char,	"%hhx",	     delim, 2, "hhx", check_uchar);
	numbers_list_fix_width(unsigned char,	"0x%hhx",    delim, 4, "hhx", check_uchar);
	numbers_list_fix_width(signed char,	"0x%hhx",    delim, 4, "hhi", check_char);
}

/*
 * List of numbers separated by delim. Each field width specifier is the
 * exact length of the corresponding value digits in the string being scanned.
 */
static void __init numbers_list_field_width_val_width(const char *delim)
{
	numbers_list_val_width(unsigned long long, "%llu",   delim, "llu", check_ull);
	numbers_list_val_width(long long,	   "%lld",   delim, "lld", check_ll);
	numbers_list_val_width(long long,	   "%lld",   delim, "lli", check_ll);
	numbers_list_val_width(unsigned long long, "%llx",   delim, "llx", check_ull);
	numbers_list_val_width(unsigned long long, "0x%llx", delim, "llx", check_ull);
	numbers_list_val_width(long long,	   "0x%llx", delim, "lli", check_ll);

	numbers_list_val_width(unsigned long,	"%lu",	     delim, "lu", check_ulong);
	numbers_list_val_width(long,		"%ld",	     delim, "ld", check_long);
	numbers_list_val_width(long,		"%ld",	     delim, "li", check_long);
	numbers_list_val_width(unsigned long,	"%lx",	     delim, "lx", check_ulong);
	numbers_list_val_width(unsigned long,	"0x%lx",     delim, "lx", check_ulong);
	numbers_list_val_width(long,		"0x%lx",     delim, "li", check_long);

	numbers_list_val_width(unsigned int,	"%u",	     delim, "u", check_uint);
	numbers_list_val_width(int,		"%d",	     delim, "d", check_int);
	numbers_list_val_width(int,		"%d",	     delim, "i", check_int);
	numbers_list_val_width(unsigned int,	"%x",	     delim, "x", check_uint);
	numbers_list_val_width(unsigned int,	"0x%x",	     delim, "x", check_uint);
	numbers_list_val_width(int,		"0x%x",	     delim, "i", check_int);

	numbers_list_val_width(unsigned short,	"%hu",	     delim, "hu", check_ushort);
	numbers_list_val_width(short,		"%hd",	     delim, "hd", check_short);
	numbers_list_val_width(short,		"%hd",	     delim, "hi", check_short);
	numbers_list_val_width(unsigned short,	"%hx",	     delim, "hx", check_ushort);
	numbers_list_val_width(unsigned short,	"0x%hx",     delim, "hx", check_ushort);
	numbers_list_val_width(short,		"0x%hx",     delim, "hi", check_short);

	numbers_list_val_width(unsigned char,	"%hhu",	     delim, "hhu", check_uchar);
	numbers_list_val_width(signed char,	"%hhd",	     delim, "hhd", check_char);
	numbers_list_val_width(signed char,	"%hhd",	     delim, "hhi", check_char);
	numbers_list_val_width(unsigned char,	"%hhx",	     delim, "hhx", check_uchar);
	numbers_list_val_width(unsigned char,	"0x%hhx",    delim, "hhx", check_uchar);
	numbers_list_val_width(signed char,	"0x%hhx",    delim, "hhi", check_char);
}

/*
 * Slice a continuous string of digits without field delimiters, containing
 * numbers of varying length, using the field width to extract each group
 * of digits. For example the hex values c0,3,bf01,303 would have a
 * string representation of "c03bf01303" and extracted with "%2x%1x%4x%3x".
 */
static void __init numbers_slice(void)
{
	numbers_list_field_width_val_width("");
}

#define test_number_prefix(T, str, scan_fmt, expect0, expect1, n_args, fn)	\
do {										\
	const T expect[2] = { expect0, expect1 };				\
	T result[2] = {~expect[0], ~expect[1]};					\
										\
	_test(fn, &expect, str, scan_fmt, n_args, &result[0], &result[1]);	\
} while (0)

/*
 * Number prefix is >= field width.
 * Expected behaviour is derived from testing userland sscanf.
 */
static void __init numbers_prefix_overflow(void)
{
	/*
	 * Negative decimal with a field of width 1, should quit scanning
	 * and return 0.
	 */
	test_number_prefix(long long,	"-1 1", "%1lld %lld",	0, 0, 0, check_ll);
	test_number_prefix(long,	"-1 1", "%1ld %ld",	0, 0, 0, check_long);
	test_number_prefix(int,		"-1 1", "%1d %d",	0, 0, 0, check_int);
	test_number_prefix(short,	"-1 1", "%1hd %hd",	0, 0, 0, check_short);
	test_number_prefix(signed char,	"-1 1", "%1hhd %hhd",	0, 0, 0, check_char);

	test_number_prefix(long long,	"-1 1", "%1lli %lli",	0, 0, 0, check_ll);
	test_number_prefix(long,	"-1 1", "%1li %li",	0, 0, 0, check_long);
	test_number_prefix(int,		"-1 1", "%1i %i",	0, 0, 0, check_int);
	test_number_prefix(short,	"-1 1", "%1hi %hi",	0, 0, 0, check_short);
	test_number_prefix(signed char,	"-1 1", "%1hhi %hhi",	0, 0, 0, check_char);

	/*
	 * 0x prefix in a field of width 1: 0 is a valid digit so should
	 * convert. Next field scan starts at the 'x' which isn't a digit so
	 * scan quits with one field converted.
	 */
	test_number_prefix(unsigned long long,	"0xA7", "%1llx%llx", 0, 0, 1, check_ull);
	test_number_prefix(unsigned long,	"0xA7", "%1lx%lx",   0, 0, 1, check_ulong);
	test_number_prefix(unsigned int,	"0xA7", "%1x%x",     0, 0, 1, check_uint);
	test_number_prefix(unsigned short,	"0xA7", "%1hx%hx",   0, 0, 1, check_ushort);
	test_number_prefix(unsigned char,	"0xA7", "%1hhx%hhx", 0, 0, 1, check_uchar);
	test_number_prefix(long long,		"0xA7", "%1lli%llx", 0, 0, 1, check_ll);
	test_number_prefix(long,		"0xA7", "%1li%lx",   0, 0, 1, check_long);
	test_number_prefix(int,			"0xA7", "%1i%x",     0, 0, 1, check_int);
	test_number_prefix(short,		"0xA7", "%1hi%hx",   0, 0, 1, check_short);
	test_number_prefix(char,		"0xA7", "%1hhi%hhx", 0, 0, 1, check_char);

	/*
	 * 0x prefix in a field of width 2 using %x conversion: first field
	 * converts to 0. Next field scan starts at the character after "0x".
	 * Both fields will convert.
	 */
	test_number_prefix(unsigned long long,	"0xA7", "%2llx%llx", 0, 0xa7, 2, check_ull);
	test_number_prefix(unsigned long,	"0xA7", "%2lx%lx",   0, 0xa7, 2, check_ulong);
	test_number_prefix(unsigned int,	"0xA7", "%2x%x",     0, 0xa7, 2, check_uint);
	test_number_prefix(unsigned short,	"0xA7", "%2hx%hx",   0, 0xa7, 2, check_ushort);
	test_number_prefix(unsigned char,	"0xA7", "%2hhx%hhx", 0, 0xa7, 2, check_uchar);

	/*
	 * 0x prefix in a field of width 2 using %i conversion: first field
	 * converts to 0. Next field scan starts at the character after "0x",
	 * which will convert if can be interpreted as decimal but will fail
	 * if it contains any hex digits (since no 0x prefix).
	 */
	test_number_prefix(long long,	"0x67", "%2lli%lli", 0, 67, 2, check_ll);
	test_number_prefix(long,	"0x67", "%2li%li",   0, 67, 2, check_long);
	test_number_prefix(int,		"0x67", "%2i%i",     0, 67, 2, check_int);
	test_number_prefix(short,	"0x67", "%2hi%hi",   0, 67, 2, check_short);
	test_number_prefix(char,	"0x67", "%2hhi%hhi", 0, 67, 2, check_char);

	test_number_prefix(long long,	"0xA7", "%2lli%lli", 0, 0,  1, check_ll);
	test_number_prefix(long,	"0xA7", "%2li%li",   0, 0,  1, check_long);
	test_number_prefix(int,		"0xA7", "%2i%i",     0, 0,  1, check_int);
	test_number_prefix(short,	"0xA7", "%2hi%hi",   0, 0,  1, check_short);
	test_number_prefix(char,	"0xA7", "%2hhi%hhi", 0, 0,  1, check_char);
}

#define _test_simple_strtoxx(T, fn, gen_fmt, expect, base)			\
do {										\
	T got;									\
	char *endp;								\
	int len;								\
	bool fail = false;							\
										\
	total_tests++;								\
	len = snprintf(test_buffer, BUF_SIZE, gen_fmt, expect);			\
	got = (fn)(test_buffer, &endp, base);					\
	pr_debug(#fn "(\"%s\", %d) -> " gen_fmt "\n", test_buffer, base, got);	\
	if (got != (expect)) {							\
		fail = true;							\
		pr_warn(#fn "(\"%s\", %d): got " gen_fmt " expected " gen_fmt "\n", \
			test_buffer, base, got, expect);			\
	} else if (endp != test_buffer + len) {					\
		fail = true;							\
		pr_warn(#fn "(\"%s\", %d) startp=0x%px got endp=0x%px expected 0x%px\n", \
			test_buffer, base, test_buffer,				\
			test_buffer + len, endp);				\
	}									\
										\
	if (fail)								\
		failed_tests++;							\
} while (0)

#define test_simple_strtoxx(T, fn, gen_fmt, base)				\
do {										\
	int i;									\
										\
	for (i = 0; i < ARRAY_SIZE(numbers); i++) {				\
		_test_simple_strtoxx(T, fn, gen_fmt, (T)numbers[i], base);	\
										\
		if (is_signed_type(T))						\
			_test_simple_strtoxx(T, fn, gen_fmt,			\
					      -(T)numbers[i], base);		\
	}									\
} while (0)

static void __init test_simple_strtoull(void)
{
	test_simple_strtoxx(unsigned long long, simple_strtoull, "%llu",   10);
	test_simple_strtoxx(unsigned long long, simple_strtoull, "%llu",   0);
	test_simple_strtoxx(unsigned long long, simple_strtoull, "%llx",   16);
	test_simple_strtoxx(unsigned long long, simple_strtoull, "0x%llx", 16);
	test_simple_strtoxx(unsigned long long, simple_strtoull, "0x%llx", 0);
}

static void __init test_simple_strtoll(void)
{
	test_simple_strtoxx(long long, simple_strtoll, "%lld",	 10);
	test_simple_strtoxx(long long, simple_strtoll, "%lld",	 0);
	test_simple_strtoxx(long long, simple_strtoll, "%llx",	 16);
	test_simple_strtoxx(long long, simple_strtoll, "0x%llx", 16);
	test_simple_strtoxx(long long, simple_strtoll, "0x%llx", 0);
}

static void __init test_simple_strtoul(void)
{
	test_simple_strtoxx(unsigned long, simple_strtoul, "%lu",   10);
	test_simple_strtoxx(unsigned long, simple_strtoul, "%lu",   0);
	test_simple_strtoxx(unsigned long, simple_strtoul, "%lx",   16);
	test_simple_strtoxx(unsigned long, simple_strtoul, "0x%lx", 16);
	test_simple_strtoxx(unsigned long, simple_strtoul, "0x%lx", 0);
}

static void __init test_simple_strtol(void)
{
	test_simple_strtoxx(long, simple_strtol, "%ld",   10);
	test_simple_strtoxx(long, simple_strtol, "%ld",   0);
	test_simple_strtoxx(long, simple_strtol, "%lx",   16);
	test_simple_strtoxx(long, simple_strtol, "0x%lx", 16);
	test_simple_strtoxx(long, simple_strtol, "0x%lx", 0);
}

/* Selection of common delimiters/separators between numbers in a string. */
static const char * const number_delimiters[] __initconst = {
	" ", ":", ",", "-", "/",
};

static void __init test_numbers(void)
{
	int i;

	/* String containing only one number. */
	numbers_simple();

	/* String with multiple numbers separated by delimiter. */
	for (i = 0; i < ARRAY_SIZE(number_delimiters); i++) {
		numbers_list(number_delimiters[i]);

		/* Field width may be longer than actual field digits. */
		numbers_list_field_width_typemax(number_delimiters[i]);

		/* Each field width exactly length of actual field digits. */
		numbers_list_field_width_val_width(number_delimiters[i]);
	}

	/* Slice continuous sequence of digits using field widths. */
	numbers_slice();

	numbers_prefix_overflow();
}

static void __init selftest(void)
{
	test_buffer = kmalloc(BUF_SIZE, GFP_KERNEL);
	if (!test_buffer)
		return;

	fmt_buffer = kmalloc(BUF_SIZE, GFP_KERNEL);
	if (!fmt_buffer) {
		kfree(test_buffer);
		return;
	}

	prandom_seed_state(&rnd_state, 3141592653589793238ULL);

	test_numbers();

	test_simple_strtoull();
	test_simple_strtoll();
	test_simple_strtoul();
	test_simple_strtol();

	kfree(fmt_buffer);
	kfree(test_buffer);
}

KSTM_MODULE_LOADERS(test_scanf);
MODULE_AUTHOR("Richard Fitzgerald <rf@opensource.cirrus.com>");
MODULE_LICENSE("GPL v2");