// SPDX-License-Identifier: GPL-2.0-only /* * lib/parser.c - simple parser for mount, etc. options. */ #include <linux/ctype.h> #include <linux/types.h> #include <linux/export.h> #include <linux/kstrtox.h> #include <linux/parser.h> #include <linux/slab.h> #include <linux/string.h> /* * max size needed by different bases to express U64 * HEX: "0xFFFFFFFFFFFFFFFF" --> 18 * DEC: "18446744073709551615" --> 20 * OCT: "01777777777777777777777" --> 23 * pick the max one to define NUMBER_BUF_LEN */ #define NUMBER_BUF_LEN 24 /** * match_one - Determines if a string matches a simple pattern * @s: the string to examine for presence of the pattern * @p: the string containing the pattern * @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match * locations. * * Description: Determines if the pattern @p is present in string @s. Can only * match extremely simple token=arg style patterns. If the pattern is found, * the location(s) of the arguments will be returned in the @args array. */ static int match_one(char *s, const char *p, substring_t args[]) { char *meta; int argc = 0; if (!p) return 1; while(1) { int len = -1; meta = strchr(p, '%'); if (!meta) return strcmp(p, s) == 0; if (strncmp(p, s, meta-p)) return 0; s += meta - p; p = meta + 1; if (isdigit(*p)) len = simple_strtoul(p, (char **) &p, 10); else if (*p == '%') { if (*s++ != '%') return 0; p++; continue; } if (argc >= MAX_OPT_ARGS) return 0; args[argc].from = s; switch (*p++) { case 's': { size_t str_len = strlen(s); if (str_len == 0) return 0; if (len == -1 || len > str_len) len = str_len; args[argc].to = s + len; break; } case 'd': simple_strtol(s, &args[argc].to, 0); goto num; case 'u': simple_strtoul(s, &args[argc].to, 0); goto num; case 'o': simple_strtoul(s, &args[argc].to, 8); goto num; case 'x': simple_strtoul(s, &args[argc].to, 16); num: if (args[argc].to == args[argc].from) return 0; break; default: return 0; } s = args[argc].to; argc++; } } /** * match_token - Find a token (and optional args) in a string * @s: the string to examine for token/argument pairs * @table: match_table_t describing the set of allowed option tokens and the * arguments that may be associated with them. Must be terminated with a * &struct match_token whose pattern is set to the NULL pointer. * @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match * locations. * * Description: Detects which if any of a set of token strings has been passed * to it. Tokens can include up to %MAX_OPT_ARGS instances of basic c-style * format identifiers which will be taken into account when matching the * tokens, and whose locations will be returned in the @args array. */ int match_token(char *s, const match_table_t table, substring_t args[]) { const struct match_token *p; for (p = table; !match_one(s, p->pattern, args) ; p++) ; return p->token; } EXPORT_SYMBOL(match_token); /** * match_number - scan a number in the given base from a substring_t * @s: substring to be scanned * @result: resulting integer on success * @base: base to use when converting string * * Description: Given a &substring_t and a base, attempts to parse the substring * as a number in that base. * * Return: On success, sets @result to the integer represented by the * string and returns 0. Returns -EINVAL or -ERANGE on failure. */ static int match_number(substring_t *s, int *result, int base) { char *endp; char buf[NUMBER_BUF_LEN]; int ret; long val; if (match_strlcpy(buf, s, NUMBER_BUF_LEN) >= NUMBER_BUF_LEN) return -ERANGE; ret = 0; val = simple_strtol(buf, &endp, base); if (endp == buf) ret = -EINVAL; else if (val < (long)INT_MIN || val > (long)INT_MAX) ret = -ERANGE; else *result = (int) val; return ret; } /** * match_u64int - scan a number in the given base from a substring_t * @s: substring to be scanned * @result: resulting u64 on success * @base: base to use when converting string * * Description: Given a &substring_t and a base, attempts to parse the substring * as a number in that base. * * Return: On success, sets @result to the integer represented by the * string and returns 0. Returns -EINVAL or -ERANGE on failure. */ static int match_u64int(substring_t *s, u64 *result, int base) { char buf[NUMBER_BUF_LEN]; int ret; u64 val; if (match_strlcpy(buf, s, NUMBER_BUF_LEN) >= NUMBER_BUF_LEN) return -ERANGE; ret = kstrtoull(buf, base, &val); if (!ret) *result = val; return ret; } /** * match_int - scan a decimal representation of an integer from a substring_t * @s: substring_t to be scanned * @result: resulting integer on success * * Description: Attempts to parse the &substring_t @s as a decimal integer. * * Return: On success, sets @result to the integer represented by the string * and returns 0. Returns -EINVAL or -ERANGE on failure. */ int match_int(substring_t *s, int *result) { return match_number(s, result, 0); } EXPORT_SYMBOL(match_int); /** * match_uint - scan a decimal representation of an integer from a substring_t * @s: substring_t to be scanned * @result: resulting integer on success * * Description: Attempts to parse the &substring_t @s as a decimal integer. * * Return: On success, sets @result to the integer represented by the string * and returns 0. Returns -EINVAL or -ERANGE on failure. */ int match_uint(substring_t *s, unsigned int *result) { char buf[NUMBER_BUF_LEN]; if (match_strlcpy(buf, s, NUMBER_BUF_LEN) >= NUMBER_BUF_LEN) return -ERANGE; return kstrtouint(buf, 10, result); } EXPORT_SYMBOL(match_uint); /** * match_u64 - scan a decimal representation of a u64 from * a substring_t * @s: substring_t to be scanned * @result: resulting unsigned long long on success * * Description: Attempts to parse the &substring_t @s as a long decimal * integer. * * Return: On success, sets @result to the integer represented by the string * and returns 0. Returns -EINVAL or -ERANGE on failure. */ int match_u64(substring_t *s, u64 *result) { return match_u64int(s, result, 0); } EXPORT_SYMBOL(match_u64); /** * match_octal - scan an octal representation of an integer from a substring_t * @s: substring_t to be scanned * @result: resulting integer on success * * Description: Attempts to parse the &substring_t @s as an octal integer. * * Return: On success, sets @result to the integer represented by the string * and returns 0. Returns -EINVAL or -ERANGE on failure. */ int match_octal(substring_t *s, int *result) { return match_number(s, result, 8); } EXPORT_SYMBOL(match_octal); /** * match_hex - scan a hex representation of an integer from a substring_t * @s: substring_t to be scanned * @result: resulting integer on success * * Description: Attempts to parse the &substring_t @s as a hexadecimal integer. * * Return: On success, sets @result to the integer represented by the string * and returns 0. Returns -EINVAL or -ERANGE on failure. */ int match_hex(substring_t *s, int *result) { return match_number(s, result, 16); } EXPORT_SYMBOL(match_hex); /** * match_wildcard - parse if a string matches given wildcard pattern * @pattern: wildcard pattern * @str: the string to be parsed * * Description: Parse the string @str to check if matches wildcard * pattern @pattern. The pattern may contain two types of wildcards: * * * '*' - matches zero or more characters * * '?' - matches one character * * Return: If the @str matches the @pattern, return true, else return false. */ bool match_wildcard(const char *pattern, const char *str) { const char *s = str; const char *p = pattern; bool star = false; while (*s) { switch (*p) { case '?': s++; p++; break; case '*': star = true; str = s; if (!*++p) return true; pattern = p; break; default: if (*s == *p) { s++; p++; } else { if (!star) return false; str++; s = str; p = pattern; } break; } } if (*p == '*') ++p; return !*p; } EXPORT_SYMBOL(match_wildcard); /** * match_strlcpy - Copy the characters from a substring_t to a sized buffer * @dest: where to copy to * @src: &substring_t to copy * @size: size of destination buffer * * Description: Copy the characters in &substring_t @src to the * c-style string @dest. Copy no more than @size - 1 characters, plus * the terminating NUL. * * Return: length of @src. */ size_t match_strlcpy(char *dest, const substring_t *src, size_t size) { size_t ret = src->to - src->from; if (size) { size_t len = ret >= size ? size - 1 : ret; memcpy(dest, src->from, len); dest[len] = '\0'; } return ret; } EXPORT_SYMBOL(match_strlcpy); /** * match_strdup - allocate a new string with the contents of a substring_t * @s: &substring_t to copy * * Description: Allocates and returns a string filled with the contents of * the &substring_t @s. The caller is responsible for freeing the returned * string with kfree(). * * Return: the address of the newly allocated NUL-terminated string or * %NULL on error. */ char *match_strdup(const substring_t *s) { return kmemdup_nul(s->from, s->to - s->from, GFP_KERNEL); } EXPORT_SYMBOL(match_strdup);
