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author | Timothy Pearson <tpearson@raptorengineering.com> | 2017-08-23 14:45:25 -0500 |
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committer | Timothy Pearson <tpearson@raptorengineering.com> | 2017-08-23 14:45:25 -0500 |
commit | fcbb27b0ec6dcbc5a5108cb8fb19eae64593d204 (patch) | |
tree | 22962a4387943edc841c72a4e636a068c66d58fd /lib/parser.c | |
download | ast2050-linux-kernel-fcbb27b0ec6dcbc5a5108cb8fb19eae64593d204.zip ast2050-linux-kernel-fcbb27b0ec6dcbc5a5108cb8fb19eae64593d204.tar.gz |
Initial import of modified Linux 2.6.28 tree
Original upstream URL:
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git | branch linux-2.6.28.y
Diffstat (limited to 'lib/parser.c')
-rw-r--r-- | lib/parser.c | 228 |
1 files changed, 228 insertions, 0 deletions
diff --git a/lib/parser.c b/lib/parser.c new file mode 100644 index 0000000..b00d020 --- /dev/null +++ b/lib/parser.c @@ -0,0 +1,228 @@ +/* + * 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, 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; +} + +/** + * 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); |