// 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/parser.h>
#include <linux/slab.h>
#include <linux/string.h>
/**
* 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. On success, sets @result to the integer represented
* by the string and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
*/
static int match_number(substring_t *s, int *result, int base)
{
char *endp;
char *buf;
int ret;
long val;
buf = match_strdup(s);
if (!buf)
return -ENOMEM;
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;
kfree(buf);
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. On success, sets @result to the integer represented
* by the string and returns 0. Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
*/
static int match_u64int(substring_t *s, u64 *result, int base)
{
char *buf;
int ret;
u64 val;
buf = match_strdup(s);
if (!buf)
return -ENOMEM;
ret = kstrtoull(buf, base, &val);
if (!ret)
*result = val;
kfree(buf);
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. On
* success, sets @result to the integer represented by the string and returns 0.
* Returns -ENOMEM, -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. On
* success, sets @result to the integer represented by the string and returns 0.
* Returns -ENOMEM, -EINVAL, or -ERANGE on failure.
*/
int match_uint(substring_t *s, unsigned int *result)
{
int err = -ENOMEM;
char *buf = match_strdup(s);
if (buf) {
err = kstrtouint(buf, 10, result);
kfree(buf);
}
return err;
}
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. On success, sets @result to the integer represented by the
* string and returns 0.
* Returns -ENOMEM, -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. On
* success, sets @result to the integer represented by the string and returns
* 0. Returns -ENOMEM, -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.
* On success, sets @result to the integer represented by the string and
* returns 0. Returns -ENOMEM, -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 type wildcardes:
* '*' - matches zero or more characters
* '?' - matches one character
* If it's matched, 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().
*/
char *match_strdup(const substring_t *s)
{
return kmemdup_nul(s->from, s->to - s->from, GFP_KERNEL);
}
EXPORT_SYMBOL(match_strdup);
