vsprintf.c

 * The return value is the number of characters which would be
 * generated for the given input, excluding the trailing null,
 * as per ISO C99.  If the return is greater than or equal to
 * @size, the resulting string is truncated.
 *
 * See the vsnprintf() documentation for format string extensions over C99.
 */
int snprintf(char *buf, size_t size, const char *fmt, ...)
{
	va_list args;
	int i;

	va_start(args, fmt);
	i = vsnprintf(buf, size, fmt, args);
	va_end(args);

	return i;
}
EXPORT_SYMBOL(snprintf);

/**
 * scnprintf - Format a string and place it in a buffer
 * @buf: The buffer to place the result into
 * @size: The size of the buffer, including the trailing null space
 * @fmt: The format string to use
 * @...: Arguments for the format string
 *
 * The return value is the number of characters written into @buf not including
 * the trailing '\0'. If @size is == 0 the function returns 0.
 */

int scnprintf(char *buf, size_t size, const char *fmt, ...)
{
	va_list args;
	int i;

	va_start(args, fmt);
	i = vscnprintf(buf, size, fmt, args);
	va_end(args);

	return i;
}
EXPORT_SYMBOL(scnprintf);

/**
 * vsprintf - Format a string and place it in a buffer
 * @buf: The buffer to place the result into
 * @fmt: The format string to use
 * @args: Arguments for the format string
 *
 * The function returns the number of characters written
 * into @buf. Use vsnprintf() or vscnprintf() in order to avoid
 * buffer overflows.
 *
 * If you're not already dealing with a va_list consider using sprintf().
 *
 * See the vsnprintf() documentation for format string extensions over C99.
 */
int vsprintf(char *buf, const char *fmt, va_list args)
{
	return vsnprintf(buf, INT_MAX, fmt, args);
}
EXPORT_SYMBOL(vsprintf);

/**
 * sprintf - Format a string and place it in a buffer
 * @buf: The buffer to place the result into
 * @fmt: The format string to use
 * @...: Arguments for the format string
 *
 * The function returns the number of characters written
 * into @buf. Use snprintf() or scnprintf() in order to avoid
 * buffer overflows.
 *
 * See the vsnprintf() documentation for format string extensions over C99.
 */
int sprintf(char *buf, const char *fmt, ...)
{
	va_list args;
	int i;

	va_start(args, fmt);
	i = vsnprintf(buf, INT_MAX, fmt, args);
	va_end(args);

	return i;
}
EXPORT_SYMBOL(sprintf);

#ifdef CONFIG_BINARY_PRINTF
/*
 * bprintf service:
 * vbin_printf() - VA arguments to binary data
 * bstr_printf() - Binary data to text string
 */

/**
 * vbin_printf - Parse a format string and place args' binary value in a buffer
 * @bin_buf: The buffer to place args' binary value
 * @size: The size of the buffer(by words(32bits), not characters)
 * @fmt: The format string to use
 * @args: Arguments for the format string
 *
 * The format follows C99 vsnprintf, except %n is ignored, and its argument
 * is skipped.
 *
 * The return value is the number of words(32bits) which would be generated for
 * the given input.
 *
 * NOTE:
 * If the return value is greater than @size, the resulting bin_buf is NOT
 * valid for bstr_printf().
 */
int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args)
{
	struct printf_spec spec = {0};
	char *str, *end;

	str = (char *)bin_buf;
	end = (char *)(bin_buf + size);

#define save_arg(type)							\
do {									\
	if (sizeof(type) == 8) {					\
		unsigned long long value;				\
		str = PTR_ALIGN(str, sizeof(u32));			\
		value = va_arg(args, unsigned long long);		\
		if (str + sizeof(type) <= end) {			\
			*(u32 *)str = *(u32 *)&value;			\
			*(u32 *)(str + 4) = *((u32 *)&value + 1);	\
		}							\
	} else {							\
		unsigned long value;					\
		str = PTR_ALIGN(str, sizeof(type));			\
		value = va_arg(args, int);				\
		if (str + sizeof(type) <= end)				\
			*(typeof(type) *)str = (type)value;		\
	}								\
	str += sizeof(type);						\
} while (0)

	while (*fmt) {
		int read = format_decode(fmt, &spec);

		fmt += read;

		switch (spec.type) {
		case FORMAT_TYPE_NONE:
		case FORMAT_TYPE_INVALID:
		case FORMAT_TYPE_PERCENT_CHAR:
			break;

		case FORMAT_TYPE_WIDTH:
		case FORMAT_TYPE_PRECISION:
			save_arg(int);
			break;

		case FORMAT_TYPE_CHAR:
			save_arg(char);
			break;

		case FORMAT_TYPE_STR: {
			const char *save_str = va_arg(args, char *);
			size_t len;

			if ((unsigned long)save_str > (unsigned long)-PAGE_SIZE
					|| (unsigned long)save_str < PAGE_SIZE)
				save_str = "(null)";
			len = strlen(save_str) + 1;
			if (str + len < end)
				memcpy(str, save_str, len);
			str += len;
			break;
		}

		case FORMAT_TYPE_PTR:
			save_arg(void *);
			/* skip all alphanumeric pointer suffixes */
			while (isalnum(*fmt))
				fmt++;
			break;

		default:
			switch (spec.type) {

			case FORMAT_TYPE_LONG_LONG:
				save_arg(long long);
				break;
			case FORMAT_TYPE_ULONG:
			case FORMAT_TYPE_LONG:
				save_arg(unsigned long);
				break;
			case FORMAT_TYPE_SIZE_T:
				save_arg(size_t);
				break;
			case FORMAT_TYPE_PTRDIFF:
				save_arg(ptrdiff_t);
				break;
			case FORMAT_TYPE_UBYTE:
			case FORMAT_TYPE_BYTE:
				save_arg(char);
				break;
			case FORMAT_TYPE_USHORT:
			case FORMAT_TYPE_SHORT:
				save_arg(short);
				break;
			default:
				save_arg(int);
			}
		}
	}

	return (u32 *)(PTR_ALIGN(str, sizeof(u32))) - bin_buf;
#undef save_arg
}
EXPORT_SYMBOL_GPL(vbin_printf);

/**
 * bstr_printf - Format a string from binary arguments and place it in a buffer
 * @buf: The buffer to place the result into
 * @size: The size of the buffer, including the trailing null space
 * @fmt: The format string to use
 * @bin_buf: Binary arguments for the format string
 *
 * This function like C99 vsnprintf, but the difference is that vsnprintf gets
 * arguments from stack, and bstr_printf gets arguments from @bin_buf which is
 * a binary buffer that generated by vbin_printf.
 *
 * The format follows C99 vsnprintf, but has some extensions:
 *  see vsnprintf comment for details.
 *
 * The return value is the number of characters which would
 * be generated for the given input, excluding the trailing
 * '\0', as per ISO C99. If you want to have the exact
 * number of characters written into @buf as return value
 * (not including the trailing '\0'), use vscnprintf(). If the
 * return is greater than or equal to @size, the resulting
 * string is truncated.
 */
int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf)
{
	struct printf_spec spec = {0};
	char *str, *end;
	const char *args = (const char *)bin_buf;

	if (WARN_ON_ONCE((int) size < 0))
		return 0;

	str = buf;
	end = buf + size;

#define get_arg(type)							\
({									\
	typeof(type) value;						\
	if (sizeof(type) == 8) {					\
		args = PTR_ALIGN(args, sizeof(u32));			\
		*(u32 *)&value = *(u32 *)args;				\
		*((u32 *)&value + 1) = *(u32 *)(args + 4);		\
	} else {							\
		args = PTR_ALIGN(args, sizeof(type));			\
		value = *(typeof(type) *)args;				\
	}								\
	args += sizeof(type);						\
	value;								\
})

	/* Make sure end is always >= buf */
	if (end < buf) {
		end = ((void *)-1);
		size = end - buf;
	}

	while (*fmt) {
		const char *old_fmt = fmt;
		int read = format_decode(fmt, &spec);

		fmt += read;

		switch (spec.type) {
		case FORMAT_TYPE_NONE: {
			int copy = read;
			if (str < end) {
				if (copy > end - str)
					copy = end - str;
				memcpy(str, old_fmt, copy);
			}
			str += read;
			break;
		}

		case FORMAT_TYPE_WIDTH:
			spec.field_width = get_arg(int);
			break;

		case FORMAT_TYPE_PRECISION:
			spec.precision = get_arg(int);
			break;

		case FORMAT_TYPE_CHAR: {
			char c;

			if (!(spec.flags & LEFT)) {
				while (--spec.field_width > 0) {
					if (str < end)
						*str = ' ';
					++str;
				}
			}
			c = (unsigned char) get_arg(char);
			if (str < end)
				*str = c;
			++str;
			while (--spec.field_width > 0) {
				if (str < end)
					*str = ' ';
				++str;
			}
			break;
		}

		case FORMAT_TYPE_STR: {
			const char *str_arg = args;
			args += strlen(str_arg) + 1;
			str = string(str, end, (char *)str_arg, spec);
			break;
		}

		case FORMAT_TYPE_PTR:
			str = pointer(fmt, str, end, get_arg(void *), spec);
			while (isalnum(*fmt))
				fmt++;
			break;

		case FORMAT_TYPE_PERCENT_CHAR:
		case FORMAT_TYPE_INVALID:
			if (str < end)
				*str = '%';
			++str;
			break;

		default: {
			unsigned long long num;

			switch (spec.type) {

			case FORMAT_TYPE_LONG_LONG:
				num = get_arg(long long);
				break;
			case FORMAT_TYPE_ULONG:
			case FORMAT_TYPE_LONG:
				num = get_arg(unsigned long);
				break;
			case FORMAT_TYPE_SIZE_T:
				num = get_arg(size_t);
				break;
			case FORMAT_TYPE_PTRDIFF:
				num = get_arg(ptrdiff_t);
				break;
			case FORMAT_TYPE_UBYTE:
				num = get_arg(unsigned char);
				break;
			case FORMAT_TYPE_BYTE:
				num = get_arg(signed char);
				break;
			case FORMAT_TYPE_USHORT:
				num = get_arg(unsigned short);
				break;
			case FORMAT_TYPE_SHORT:
				num = get_arg(short);
				break;
			case FORMAT_TYPE_UINT:
				num = get_arg(unsigned int);
				break;
			default:
				num = get_arg(int);
			}

			str = number(str, end, num, spec);
		} /* default: */
		} /* switch(spec.type) */
	} /* while(*fmt) */

	if (size > 0) {
		if (str < end)
			*str = '\0';
		else
			end[-1] = '\0';
	}

#undef get_arg

	/* the trailing null byte doesn't count towards the total */
	return str - buf;
}
EXPORT_SYMBOL_GPL(bstr_printf);

/**
 * bprintf - Parse a format string and place args' binary value in a buffer
 * @bin_buf: The buffer to place args' binary value
 * @size: The size of the buffer(by words(32bits), not characters)
 * @fmt: The format string to use
 * @...: Arguments for the format string
 *
 * The function returns the number of words(u32) written
 * into @bin_buf.
 */
int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...)
{
	va_list args;
	int ret;

	va_start(args, fmt);
	ret = vbin_printf(bin_buf, size, fmt, args);
	va_end(args);

	return ret;
}
EXPORT_SYMBOL_GPL(bprintf);

#endif /* CONFIG_BINARY_PRINTF */

/**
 * vsscanf - Unformat a buffer into a list of arguments
 * @buf:	input buffer
 * @fmt:	format of buffer
 * @args:	arguments
 */
int vsscanf(const char *buf, const char *fmt, va_list args)
{
	const char *str = buf;
	char *next;
	char digit;
	int num = 0;
	u8 qualifier;
	unsigned int base;
	union {
		long long s;
		unsigned long long u;
	} val;
	s16 field_width;
	bool is_sign;

	while (*fmt) {
		/* skip any white space in format */
		/* white space in format matchs any amount of
		 * white space, including none, in the input.
		 */
		if (isspace(*fmt)) {
			fmt = skip_spaces(++fmt);
			str = skip_spaces(str);
		}

		/* anything that is not a conversion must match exactly */
		if (*fmt != '%' && *fmt) {
			if (*fmt++ != *str++)
				break;
			continue;
		}

		if (!*fmt)
			break;
		++fmt;

		/* skip this conversion.
		 * advance both strings to next white space
		 */
		if (*fmt == '*') {
			if (!*str)
				break;
			while (!isspace(*fmt) && *fmt != '%' && *fmt)
				fmt++;
			while (!isspace(*str) && *str)
				str++;
			continue;
		}

		/* get field width */
		field_width = -1;
		if (isdigit(*fmt)) {
			field_width = skip_atoi(&fmt);
			if (field_width <= 0)
				break;
		}

		/* get conversion qualifier */
		qualifier = -1;
		if (*fmt == 'h' || _tolower(*fmt) == 'l' ||
		    _tolower(*fmt) == 'z') {
			qualifier = *fmt++;
			if (unlikely(qualifier == *fmt)) {
				if (qualifier == 'h') {
					qualifier = 'H';
					fmt++;
				} else if (qualifier == 'l') {
					qualifier = 'L';
					fmt++;
				}
			}
		}

		if (!*fmt)
			break;

		if (*fmt == 'n') {
			/* return number of characters read so far */
			*va_arg(args, int *) = str - buf;
			++fmt;
			continue;
		}

		if (!*str)
			break;

		base = 10;
		is_sign = false;

		switch (*fmt++) {
		case 'c':
		{
			char *s = (char *)va_arg(args, char*);
			if (field_width == -1)
				field_width = 1;
			do {
				*s++ = *str++;
			} while (--field_width > 0 && *str);
			num++;
		}
		continue;
		case 's':
		{
			char *s = (char *)va_arg(args, char *);
			if (field_width == -1)
				field_width = SHRT_MAX;
			/* first, skip leading white space in buffer */
			str = skip_spaces(str);

			/* now copy until next white space */
			while (*str && !isspace(*str) && field_width--)
				*s++ = *str++;
			*s = '\0';
			num++;
		}
		continue;
		case 'o':
			base = 8;
			break;
		case 'x':
		case 'X':
			base = 16;
			break;
		case 'i':
			base = 0;
		case 'd':
			is_sign = true;
		case 'u':
			break;
		case '%':
			/* looking for '%' in str */
			if (*str++ != '%')
				return num;
			continue;
		default:
			/* invalid format; stop here */
			return num;
		}

		/* have some sort of integer conversion.
		 * first, skip white space in buffer.
		 */
		str = skip_spaces(str);

		digit = *str;
		if (is_sign && digit == '-')
			digit = *(str + 1);

		if (!digit
		    || (base == 16 && !isxdigit(digit))
		    || (base == 10 && !isdigit(digit))
		    || (base == 8 && (!isdigit(digit) || digit > '7'))
		    || (base == 0 && !isdigit(digit)))
			break;

		if (is_sign)
			val.s = qualifier != 'L' ?
				simple_strtol(str, &next, base) :
				simple_strtoll(str, &next, base);
		else
			val.u = qualifier != 'L' ?
				simple_strtoul(str, &next, base) :
				simple_strtoull(str, &next, base);

		if (field_width > 0 && next - str > field_width) {
			if (base == 0)
				_parse_integer_fixup_radix(str, &base);
			while (next - str > field_width) {
				if (is_sign)
					val.s = div_s64(val.s, base);
				else
					val.u = div_u64(val.u, base);
				--next;
			}
		}

		switch (qualifier) {
		case 'H':	/* that's 'hh' in format */
			if (is_sign)
				*va_arg(args, signed char *) = val.s;
			else
				*va_arg(args, unsigned char *) = val.u;
			break;
		case 'h':
			if (is_sign)
				*va_arg(args, short *) = val.s;
			else
				*va_arg(args, unsigned short *) = val.u;
			break;
		case 'l':
			if (is_sign)
				*va_arg(args, long *) = val.s;
			else
				*va_arg(args, unsigned long *) = val.u;
			break;
		case 'L':
			if (is_sign)
				*va_arg(args, long long *) = val.s;
			else
				*va_arg(args, unsigned long long *) = val.u;
			break;
		case 'Z':
		case 'z':
			*va_arg(args, size_t *) = val.u;
			break;
		default:
			if (is_sign)
				*va_arg(args, int *) = val.s;
			else
				*va_arg(args, unsigned int *) = val.u;
			break;
		}
		num++;

		if (!next)
			break;
		str = next;
	}

	return num;
}
EXPORT_SYMBOL(vsscanf);

/**
 * sscanf - Unformat a buffer into a list of arguments
 * @buf:	input buffer
 * @fmt:	formatting of buffer
 * @...:	resulting arguments
 */
int sscanf(const char *buf, const char *fmt, ...)
{
	va_list args;
	int i;

	va_start(args, fmt);
	i = vsscanf(buf, fmt, args);
	va_end(args);

	return i;
}
EXPORT_SYMBOL(sscanf);