v4.19.13 snapshot.
diff --git a/lib/parser.c b/lib/parser.c
new file mode 100644
index 0000000..3278958
--- /dev/null
+++ b/lib/parser.c
@@ -0,0 +1,336 @@
+/*
+ * 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_u64int: scan a number in the given base from a substring_t
+ * @s: substring to be scanned
+ * @result: resulting u64 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_u64int(substring_t *s, u64 *result, int base)
+{
+ char *buf;
+ int ret;
+ u64 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 = kstrtoull(buf, base, &val);
+ if (!ret)
+ *result = 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_u64: - scan a decimal representation of a u64 from
+ * a substring_t
+ * @s: substring_t to be scanned
+ * @result: resulting unsigned long long on success
+ *
+ * Description: Attempts to parse the &substring_t @s as a long 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_u64(substring_t *s, u64 *result)
+{
+ return match_u64int(s, result, 0);
+}
+EXPORT_SYMBOL(match_u64);
+
+/**
+ * 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);