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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 | /* * 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/module.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 presense 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': if (strlen(s) == 0) return 0; else if (len == -1 || len > strlen(s)) len = strlen(s); 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, 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; } /** * 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 either -ENOMEM or -EINVAL on failure. */ static int match_number(substring_t *s, int *result, int base) { char *endp; char *buf; int ret; buf = kmalloc(s->to - s->from + 1, GFP_KERNEL); if (!buf) return -ENOMEM; memcpy(buf, s->from, s->to - s->from); buf[s->to - s->from] = '\0'; *result = simple_strtol(buf, &endp, base); ret = 0; if (endp == buf) ret = -EINVAL; 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 either -ENOMEM or -EINVAL on failure. */ int match_int(substring_t *s, int *result) { return match_number(s, result, 0); } /** * 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 either -ENOMEM or -EINVAL on failure. */ int match_octal(substring_t *s, int *result) { return match_number(s, result, 8); } /** * 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 either -ENOMEM or -EINVAL on failure. */ int match_hex(substring_t *s, int *result) { return match_number(s, result, 16); } /** * 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; } /** * 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_token); EXPORT_SYMBOL(match_int); EXPORT_SYMBOL(match_octal); EXPORT_SYMBOL(match_hex); EXPORT_SYMBOL(match_strlcpy); EXPORT_SYMBOL(match_strdup); |