// SPDX-License-Identifier: GPL-2.0-only #include <linux/bitmap.h>#include <linux/ctype.h>#include <linux/errno.h>#include <linux/err.h>#include <linux/export.h>#include <linux/hex.h>#include <linux/kernel.h>#include <linux/mm.h>#include <linux/string.h> #include "kstrtox.h" /** * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap * * @ubuf: pointer to user buffer containing string. * @ulen: buffer size in bytes.  If string is smaller than this *    then it must be terminated with a \0. * @maskp: pointer to bitmap array that will contain result. * @nmaskbits: size of bitmap, in bits. */int bitmap_parse_user(const char __user *ubuf,			unsigned int ulen, unsigned long *maskp,			int nmaskbits){	char *buf;	int ret; 	buf = memdup_user_nul(ubuf, ulen);	if (IS_ERR(buf))		return PTR_ERR(buf); 	ret = bitmap_parse(buf, UINT_MAX, maskp, nmaskbits); 	kfree(buf);	return ret;}EXPORT_SYMBOL(bitmap_parse_user); /** * bitmap_print_to_buf  - convert bitmap to list or hex format ASCII string * @list: indicates whether the bitmap must be list *      true:  print in decimal list format *      false: print in hexadecimal bitmask format * @buf: buffer into which string is placed * @maskp: pointer to bitmap to convert * @nmaskbits: size of bitmap, in bits * @off: in the string from which we are copying, We copy to @buf * @count: the maximum number of bytes to print */static int bitmap_print_to_buf(bool list, char *buf, const unsigned long *maskp,		int nmaskbits, loff_t off, size_t count){	const char *fmt = list ? "%*pbl\n" : "%*pb\n";	ssize_t size;	void *data; 	data = kasprintf(GFP_KERNEL, fmt, nmaskbits, maskp);	if (!data)		return -ENOMEM; 	size = memory_read_from_buffer(buf, count, &off, data, strlen(data) + 1);	kfree(data); 	return size;} /** * bitmap_print_bitmask_to_buf  - convert bitmap to hex bitmask format ASCII string * @buf: buffer into which string is placed * @maskp: pointer to bitmap to convert * @nmaskbits: size of bitmap, in bits * @off: in the string from which we are copying, We copy to @buf * @count: the maximum number of bytes to print * * The sprintf("%*pb[l]") format is used by drivers to export hexadecimal * bitmask and decimal list to userspace by sysfs ABI. * Drivers might be using a normal attribute for this kind of ABIs. A * normal attribute typically has show entry as below:: * *   static ssize_t example_attribute_show(struct device *dev, *		struct device_attribute *attr, char *buf) *   { *	... *	return scnprintf(buf, PAGE_SIZE - offset_in_page(buf), nr_trig_max, &mask); *   } * * show entry of attribute has no offset and count parameters and this * means the file is limited to one page only. * * The problem is once we have a large bitmap, we have a chance to get a * bitmask or list more than one page. Especially for list, it could be * as complex as 0,3,5,7,9,... We have no simple way to know it exact size. * It turns out bin_attribute is a way to break this limit. bin_attribute * has show entry as below:: * *   static ssize_t *   example_bin_attribute_show(struct file *filp, struct kobject *kobj, *		struct bin_attribute *attr, char *buf, *		loff_t offset, size_t count) *   { *	... *   } * * With the new offset and count parameters, this makes sysfs ABI be able * to support file size more than one page. For example, offset could be * >= 4096. * bitmap_print_bitmask_to_buf(), bitmap_print_list_to_buf() wit their * cpumap wrapper cpumap_print_bitmask_to_buf(), cpumap_print_list_to_buf() * make those drivers be able to support large bitmask and list after they * move to use bin_attribute. In result, we have to pass the corresponding * parameters such as off, count from bin_attribute show entry to this API. * * The role of cpumap_print_bitmask_to_buf() and cpumap_print_list_to_buf() * is similar to direct sysfs_emit("%*pb[l]") formatting, but the latter * assumes the destination buffer is exactly one page and won't be more than * one page. * cpumap_print_bitmask_to_buf() and cpumap_print_list_to_buf(), on the other * hand, mainly serves bin_attribute which doesn't work with exact one page, * and it can break the size limit of converted decimal list and hexadecimal * bitmask. * * WARNING! * * This function is not a replacement for sprintf(). * * It is intended to workaround sysfs limitations discussed above and should be * used carefully in general case for the following reasons: * *  - Time complexity is O(nbits^2/count), comparing to O(nbits) for snprintf(). *  - Memory complexity is O(nbits), comparing to O(1) for snprintf(). *  - @off and @count are NOT offset and number of bits to print. *  - If printing part of bitmap as list, the resulting string is not a correct *    list representation of bitmap. Particularly, some bits within or out of *    related interval may be erroneously set or unset. The format of the string *    may be broken, so bitmap_parselist-like parser may fail parsing it. *  - If printing the whole bitmap as list by parts, user must ensure the order *    of calls of the function such that the offset is incremented linearly. *  - If printing the whole bitmap as list by parts, user must keep bitmap *    unchanged between the very first and very last call. Otherwise concatenated *    result may be incorrect, and format may be broken. * * Returns the number of characters actually printed to @buf */int bitmap_print_bitmask_to_buf(char *buf, const unsigned long *maskp,				int nmaskbits, loff_t off, size_t count){	return bitmap_print_to_buf(false, buf, maskp, nmaskbits, off, count);}EXPORT_SYMBOL(bitmap_print_bitmask_to_buf); /** * bitmap_print_list_to_buf  - convert bitmap to decimal list format ASCII string * @buf: buffer into which string is placed * @maskp: pointer to bitmap to convert * @nmaskbits: size of bitmap, in bits * @off: in the string from which we are copying, We copy to @buf * @count: the maximum number of bytes to print * * Everything is same with the above bitmap_print_bitmask_to_buf() except * the print format. */int bitmap_print_list_to_buf(char *buf, const unsigned long *maskp,			     int nmaskbits, loff_t off, size_t count){	return bitmap_print_to_buf(true, buf, maskp, nmaskbits, off, count);}EXPORT_SYMBOL(bitmap_print_list_to_buf); /* * Region 9-38:4/10 describes the following bitmap structure: * 0	   9  12    18			38	     N * .........****......****......****.................. *	    ^  ^     ^			 ^	     ^ *      start  off   group_len	       end	 nbits */struct region {	unsigned int start;	unsigned int off;	unsigned int group_len;	unsigned int end;	unsigned int nbits;}; static void bitmap_set_region(const struct region *r, unsigned long *bitmap){	unsigned int start; 	for (start = r->start; start <= r->end; start += r->group_len)		bitmap_set(bitmap, start, min(r->end - start + 1, r->off));} static int bitmap_check_region(const struct region *r){	if (r->start > r->end || r->group_len == 0 || r->off > r->group_len)		return -EINVAL; 	if (r->end >= r->nbits)		return -ERANGE; 	return 0;} static const char *bitmap_getnum(const char *str, unsigned int *num,				 unsigned int lastbit){	unsigned long long n;	unsigned int len; 	if (str[0] == 'N') {		*num = lastbit;		return str + 1;	} 	len = _parse_integer(str, 10, &n);	if (!len)		return ERR_PTR(-EINVAL);	if (len & KSTRTOX_OVERFLOW || n != (unsigned int)n)		return ERR_PTR(-EOVERFLOW); 	*num = n;	return str + len;} static inline bool end_of_str(char c){	return c == '\0' || c == '\n';} static inline bool __end_of_region(char c){	return isspace(c) || c == ',';} static inline bool end_of_region(char c){	return __end_of_region(c) || end_of_str(c);} /* * The format allows commas and whitespaces at the beginning * of the region. */static const char *bitmap_find_region(const char *str){	while (__end_of_region(*str))		str++; 	return end_of_str(*str) ? NULL : str;} static const char *bitmap_find_region_reverse(const char *start, const char *end){	while (start <= end && __end_of_region(*end))		end--; 	return end;} static const char *bitmap_parse_region(const char *str, struct region *r){	unsigned int lastbit = r->nbits - 1; 	if (!strncasecmp(str, "all", 3)) {		r->start = 0;		r->end = lastbit;		str += 3; 		goto check_pattern;	} 	str = bitmap_getnum(str, &r->start, lastbit);	if (IS_ERR(str))		return str; 	if (end_of_region(*str))		goto no_end; 	if (*str != '-')		return ERR_PTR(-EINVAL); 	str = bitmap_getnum(str + 1, &r->end, lastbit);	if (IS_ERR(str))		return str; check_pattern:	if (end_of_region(*str))		goto no_pattern; 	if (*str != ':')		return ERR_PTR(-EINVAL); 	str = bitmap_getnum(str + 1, &r->off, lastbit);	if (IS_ERR(str))		return str; 	if (*str != '/')		return ERR_PTR(-EINVAL); 	return bitmap_getnum(str + 1, &r->group_len, lastbit); no_end:	r->end = r->start;no_pattern:	r->off = r->end + 1;	r->group_len = r->end + 1; 	return end_of_str(*str) ? NULL : str;} /** * bitmap_parselist - convert list format ASCII string to bitmap * @buf: read user string from this buffer; must be terminated *    with a \0 or \n. * @maskp: write resulting mask here * @nmaskbits: number of bits in mask to be written * * Input format is a comma-separated list of decimal numbers and * ranges.  Consecutively set bits are shown as two hyphen-separated * decimal numbers, the smallest and largest bit numbers set in * the range. * Optionally each range can be postfixed to denote that only parts of it * should be set. The range will divided to groups of specific size. * From each group will be used only defined amount of bits. * Syntax: range:used_size/group_size * Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769 * The value 'N' can be used as a dynamically substituted token for the * maximum allowed value; i.e (nmaskbits - 1).  Keep in mind that it is * dynamic, so if system changes cause the bitmap width to change, such * as more cores in a CPU list, then any ranges using N will also change. * * Returns: 0 on success, -errno on invalid input strings. Error values: * *   - ``-EINVAL``: wrong region format *   - ``-EINVAL``: invalid character in string *   - ``-ERANGE``: bit number specified too large for mask *   - ``-EOVERFLOW``: integer overflow in the input parameters */int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits){	struct region r;	long ret; 	r.nbits = nmaskbits;	bitmap_zero(maskp, r.nbits); 	while (buf) {		buf = bitmap_find_region(buf);		if (buf == NULL)			return 0; 		buf = bitmap_parse_region(buf, &r);		if (IS_ERR(buf))			return PTR_ERR(buf); 		ret = bitmap_check_region(&r);		if (ret)			return ret; 		bitmap_set_region(&r, maskp);	} 	return 0;}EXPORT_SYMBOL(bitmap_parselist);  /** * bitmap_parselist_user() - convert user buffer's list format ASCII * string to bitmap * * @ubuf: pointer to user buffer containing string. * @ulen: buffer size in bytes.  If string is smaller than this *    then it must be terminated with a \0. * @maskp: pointer to bitmap array that will contain result. * @nmaskbits: size of bitmap, in bits. * * Wrapper for bitmap_parselist(), providing it with user buffer. */int bitmap_parselist_user(const char __user *ubuf,			unsigned int ulen, unsigned long *maskp,			int nmaskbits){	char *buf;	int ret; 	buf = memdup_user_nul(ubuf, ulen);	if (IS_ERR(buf))		return PTR_ERR(buf); 	ret = bitmap_parselist(buf, maskp, nmaskbits); 	kfree(buf);	return ret;}EXPORT_SYMBOL(bitmap_parselist_user); static const char *bitmap_get_x32_reverse(const char *start,					const char *end, u32 *num){	u32 ret = 0;	int c, i; 	for (i = 0; i < 32; i += 4) {		c = hex_to_bin(*end--);		if (c < 0)			return ERR_PTR(-EINVAL); 		ret |= c << i; 		if (start > end || __end_of_region(*end))			goto out;	} 	if (hex_to_bin(*end--) >= 0)		return ERR_PTR(-EOVERFLOW);out:	*num = ret;	return end;} /** * bitmap_parse - convert an ASCII hex string into a bitmap. * @start: pointer to buffer containing string. * @buflen: buffer size in bytes.  If string is smaller than this *    then it must be terminated with a \0 or \n. In that case, *    UINT_MAX may be provided instead of string length. * @maskp: pointer to bitmap array that will contain result. * @nmaskbits: size of bitmap, in bits. * * Commas group hex digits into chunks.  Each chunk defines exactly 32 * bits of the resultant bitmask.  No chunk may specify a value larger * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value * then leading 0-bits are prepended.  %-EINVAL is returned for illegal * characters. Grouping such as "1,,5", ",44", "," or "" is allowed. * Leading, embedded and trailing whitespace accepted. */int bitmap_parse(const char *start, unsigned int buflen,		unsigned long *maskp, int nmaskbits){	const char *end = strnchrnul(start, buflen, '\n') - 1;	int chunks = BITS_TO_U32(nmaskbits);	u32 *bitmap = (u32 *)maskp;	int unset_bit;	int chunk; 	for (chunk = 0; ; chunk++) {		end = bitmap_find_region_reverse(start, end);		if (start > end)			break; 		if (!chunks--)			return -EOVERFLOW; #if defined(CONFIG_64BIT) && defined(__BIG_ENDIAN)		end = bitmap_get_x32_reverse(start, end, &bitmap[chunk ^ 1]);#else		end = bitmap_get_x32_reverse(start, end, &bitmap[chunk]);#endif		if (IS_ERR(end))			return PTR_ERR(end);	} 	unset_bit = (BITS_TO_U32(nmaskbits) - chunks) * 32;	if (unset_bit < nmaskbits) {		bitmap_clear(maskp, unset_bit, nmaskbits - unset_bit);		return 0;	} 	if (find_next_bit(maskp, unset_bit, nmaskbits) != unset_bit)		return -EOVERFLOW; 	return 0;}EXPORT_SYMBOL(bitmap_parse);