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/* |
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* lib/parser.c - simple parser for mount, etc. options. |
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* |
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* This source code is licensed under the GNU General Public License, |
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* Version 2. See the file COPYING for more details. |
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*/ |
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|
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#include <linux/config.h> |
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#ifdef CONFIG_MODVERSIONS |
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#define MODVERSIONS |
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#include <linux/modversions.h> |
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#endif |
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|
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#include "parser.h" |
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|
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#include <linux/ctype.h> |
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#include <linux/module.h> |
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#include <linux/slab.h> |
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#include <linux/string.h> |
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|
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/** |
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* match_one: - Determines if a string matches a simple pattern |
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* @s: the string to examine for presense of the pattern |
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* @p: the string containing the pattern |
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* @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match |
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* locations. |
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* |
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* Description: Determines if the pattern @p is present in string @s. Can only |
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* match extremely simple token=arg style patterns. If the pattern is found, |
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* the location(s) of the arguments will be returned in the @args array. |
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*/ |
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static int match_one(char *s, char *p, substring_t args[]) |
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{ |
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char *meta; |
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int argc = 0; |
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|
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if (!p) |
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return 1; |
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|
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while(1) { |
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int len = -1; |
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meta = strchr(p, '%'); |
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if (!meta) |
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return strcmp(p, s) == 0; |
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|
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if (strncmp(p, s, meta-p)) |
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return 0; |
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|
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s += meta - p; |
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p = meta + 1; |
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|
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if (isdigit(*p)) |
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len = simple_strtoul(p, &p, 10); |
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else if (*p == '%') { |
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if (*s++ != '%') |
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return 0; |
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continue; |
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} |
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|
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if (argc >= MAX_OPT_ARGS) |
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return 0; |
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|
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args[argc].from = s; |
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switch (*p++) { |
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case 's': |
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if (strlen(s) == 0) |
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return 0; |
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else if (len == -1 || len > strlen(s)) |
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len = strlen(s); |
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args[argc].to = s + len; |
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break; |
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case 'd': |
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simple_strtol(s, &args[argc].to, 0); |
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goto num; |
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case 'u': |
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simple_strtoul(s, &args[argc].to, 0); |
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goto num; |
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case 'o': |
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simple_strtoul(s, &args[argc].to, 8); |
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goto num; |
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case 'x': |
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simple_strtoul(s, &args[argc].to, 16); |
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num: |
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if (args[argc].to == args[argc].from) |
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return 0; |
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break; |
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default: |
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return 0; |
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} |
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s = args[argc].to; |
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argc++; |
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} |
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} |
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|
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/** |
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* match_token: - Find a token (and optional args) in a string |
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* @s: the string to examine for token/argument pairs |
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* @table: match_table_t describing the set of allowed option tokens and the |
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* arguments that may be associated with them. Must be terminated with a |
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* &struct match_token whose pattern is set to the NULL pointer. |
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* @args: array of %MAX_OPT_ARGS &substring_t elements. Used to return match |
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* locations. |
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* |
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* Description: Detects which if any of a set of token strings has been passed |
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* to it. Tokens can include up to MAX_OPT_ARGS instances of basic c-style |
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* format identifiers which will be taken into account when matching the |
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* tokens, and whose locations will be returned in the @args array. |
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*/ |
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int match_token(char *s, match_table_t table, substring_t args[]) |
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{ |
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struct match_token *p; |
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|
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for (p = table; !match_one(s, p->pattern, args) ; p++) |
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; |
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|
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return p->token; |
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} |
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|
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/** |
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* match_number: scan a number in the given base from a substring_t |
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* @s: substring to be scanned |
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* @result: resulting integer on success |
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* @base: base to use when converting string |
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* |
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* Description: Given a &substring_t and a base, attempts to parse the substring |
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* as a number in that base. On success, sets @result to the integer represented |
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* by the string and returns 0. Returns either -ENOMEM or -EINVAL on failure. |
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*/ |
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static int match_number(substring_t *s, int *result, int base) |
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{ |
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char *endp; |
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char *buf; |
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int ret; |
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|
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buf = kmalloc(s->to - s->from + 1, GFP_KERNEL); |
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if (!buf) |
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return -ENOMEM; |
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memcpy(buf, s->from, s->to - s->from); |
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buf[s->to - s->from] = '\0'; |
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*result = simple_strtol(buf, &endp, base); |
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ret = 0; |
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if (endp == buf) |
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ret = -EINVAL; |
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kfree(buf); |
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return ret; |
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} |
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|
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/** |
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* match_int: - scan a decimal representation of an integer from a substring_t |
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* @s: substring_t to be scanned |
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* @result: resulting integer on success |
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* |
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* Description: Attempts to parse the &substring_t @s as a decimal integer. On |
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* success, sets @result to the integer represented by the string and returns 0. |
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* Returns either -ENOMEM or -EINVAL on failure. |
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*/ |
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int match_int(substring_t *s, int *result) |
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{ |
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return match_number(s, result, 0); |
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} |
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|
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/** |
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* match_octal: - scan an octal representation of an integer from a substring_t |
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* @s: substring_t to be scanned |
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* @result: resulting integer on success |
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* |
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* Description: Attempts to parse the &substring_t @s as an octal integer. On |
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* success, sets @result to the integer represented by the string and returns |
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* 0. Returns either -ENOMEM or -EINVAL on failure. |
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*/ |
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int match_octal(substring_t *s, int *result) |
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{ |
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return match_number(s, result, 8); |
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} |
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|
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/** |
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* match_hex: - scan a hex representation of an integer from a substring_t |
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* @s: substring_t to be scanned |
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* @result: resulting integer on success |
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* |
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* Description: Attempts to parse the &substring_t @s as a hexadecimal integer. |
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* On success, sets @result to the integer represented by the string and |
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* returns 0. Returns either -ENOMEM or -EINVAL on failure. |
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*/ |
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int match_hex(substring_t *s, int *result) |
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{ |
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return match_number(s, result, 16); |
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} |
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|
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/** |
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* match_strcpy: - copies the characters from a substring_t to a string |
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* @to: string to copy characters to. |
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* @s: &substring_t to copy |
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* |
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* Description: Copies the set of characters represented by the given |
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* &substring_t @s to the c-style string @to. Caller guarantees that @to is |
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* large enough to hold the characters of @s. |
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*/ |
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void match_strcpy(char *to, substring_t *s) |
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{ |
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memcpy(to, s->from, s->to - s->from); |
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to[s->to - s->from] = '\0'; |
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} |
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|
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/** |
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* match_strdup: - allocate a new string with the contents of a substring_t |
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* @s: &substring_t to copy |
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* |
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* Description: Allocates and returns a string filled with the contents of |
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* the &substring_t @s. The caller is responsible for freeing the returned |
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* string with kfree(). |
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*/ |
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char *match_strdup(substring_t *s) |
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{ |
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char *p = kmalloc(s->to - s->from + 1, GFP_KERNEL); |
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if (p) |
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match_strcpy(p, s); |
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return p; |
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} |
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|