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authorTimothy Pearson <tpearson@raptorengineering.com>2017-08-23 14:45:25 -0500
committerTimothy Pearson <tpearson@raptorengineering.com>2017-08-23 14:45:25 -0500
commitfcbb27b0ec6dcbc5a5108cb8fb19eae64593d204 (patch)
tree22962a4387943edc841c72a4e636a068c66d58fd /lib/parser.c
downloadast2050-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.c228
1 files changed, 228 insertions, 0 deletions
diff --git a/lib/parser.c b/lib/parser.c
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+++ b/lib/parser.c
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+/*
+ * 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);
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