diff options
Diffstat (limited to 'lib/parser.c')
-rw-r--r-- | lib/parser.c | 289 |
1 files changed, 289 insertions, 0 deletions
diff --git a/lib/parser.c b/lib/parser.c new file mode 100644 index 000000000..b6d116312 --- /dev/null +++ b/lib/parser.c @@ -0,0 +1,289 @@ +/* + * lib/parser.c - simple parser for mount, etc. options. + * + * This source code is licensed under the GNU General Public License, + * Version 2. See the file COPYING for more details. + */ + +#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; + size_t len = s->to - s->from; + + buf = kmalloc(len + 1, GFP_KERNEL); + if (!buf) + return -ENOMEM; + memcpy(buf, s->from, len); + buf[len] = '\0'; + + 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_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_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) +{ + size_t sz = s->to - s->from + 1; + char *p = kmalloc(sz, GFP_KERNEL); + if (p) + match_strlcpy(p, s, sz); + return p; +} +EXPORT_SYMBOL(match_strdup); |