[RFC PATCH 18/30] codetag: add codetag query helper functions

[Suren Baghdasaryan <surenb@google.com>]

From: Kent Overstreet <kent.overstreet@linux.dev>

Provide codetag_query_parse() to parse codetag queries and
codetag_matches_query() to check if the query affects a given codetag.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---
 include/linux/codetag.h |  27 ++++++++
 lib/codetag.c           | 135 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 162 insertions(+)

diff --git a/include/linux/codetag.h b/include/linux/codetag.h
index 386733e89b31..0c605417ebbe 100644
--- a/include/linux/codetag.h
+++ b/include/linux/codetag.h
@@ -80,4 +80,31 @@ static inline void codetag_load_module(struct module *mod) {}
 static inline void codetag_unload_module(struct module *mod) {}
 #endif
 
+/* Codetag query parsing */
+
+struct codetag_query {
+	const char	*filename;
+	const char	*module;
+	const char	*function;
+	const char	*class;
+	unsigned int	first_line, last_line;
+	unsigned int	first_index, last_index;
+	unsigned int	cur_index;
+
+	bool		match_line:1;
+	bool		match_index:1;
+
+	unsigned int	set_enabled:1;
+	unsigned int	enabled:2;
+
+	unsigned int	set_frequency:1;
+	unsigned int	frequency;
+};
+
+char *codetag_query_parse(struct codetag_query *q, char *buf);
+bool codetag_matches_query(struct codetag_query *q,
+			   const struct codetag *ct,
+			   const struct codetag_module *mod,
+			   const char *class);
+
 #endif /* _LINUX_CODETAG_H */
diff --git a/lib/codetag.c b/lib/codetag.c
index f0a3174f9b71..288ccfd5cbd0 100644
--- a/lib/codetag.c
+++ b/lib/codetag.c
@@ -246,3 +246,138 @@ void codetag_unload_module(struct module *mod)
 	}
 	mutex_unlock(&codetag_lock);
 }
+
+/* Codetag query parsing */
+
+#define CODETAG_QUERY_TOKENS()	\
+	x(func)			\
+	x(file)			\
+	x(line)			\
+	x(module)		\
+	x(class)		\
+	x(index)
+
+enum tokens {
+#define x(name)		TOK_##name,
+	CODETAG_QUERY_TOKENS()
+#undef x
+};
+
+static const char * const token_strs[] = {
+#define x(name)		#name,
+	CODETAG_QUERY_TOKENS()
+#undef x
+	NULL
+};
+
+static int parse_range(char *str, unsigned int *first, unsigned int *last)
+{
+	char *first_str = str;
+	char *last_str = strchr(first_str, '-');
+
+	if (last_str)
+		*last_str++ = '\0';
+
+	if (kstrtouint(first_str, 10, first))
+		return -EINVAL;
+
+	if (!last_str)
+		*last = *first;
+	else if (kstrtouint(last_str, 10, last))
+		return -EINVAL;
+
+	return 0;
+}
+
+char *codetag_query_parse(struct codetag_query *q, char *buf)
+{
+	while (1) {
+		char *p = buf;
+		char *str1 = strsep_no_empty(&p, " \t\r\n");
+		char *str2 = strsep_no_empty(&p, " \t\r\n");
+		int ret, token;
+
+		if (!str1 || !str2)
+			break;
+
+		token = match_string(token_strs, ARRAY_SIZE(token_strs), str1);
+		if (token < 0)
+			break;
+
+		switch (token) {
+		case TOK_func:
+			q->function = str2;
+			break;
+		case TOK_file:
+			q->filename = str2;
+			break;
+		case TOK_line:
+			ret = parse_range(str2, &q->first_line, &q->last_line);
+			if (ret)
+				return ERR_PTR(ret);
+			q->match_line = true;
+			break;
+		case TOK_module:
+			q->module = str2;
+			break;
+		case TOK_class:
+			q->class = str2;
+			break;
+		case TOK_index:
+			ret = parse_range(str2, &q->first_index, &q->last_index);
+			if (ret)
+				return ERR_PTR(ret);
+			q->match_index = true;
+			break;
+		}
+
+		buf = p;
+	}
+
+	return buf;
+}
+
+bool codetag_matches_query(struct codetag_query *q,
+			   const struct codetag *ct,
+			   const struct codetag_module *mod,
+			   const char *class)
+{
+	size_t classlen = q->class ? strlen(q->class) : 0;
+
+	if (q->module &&
+	    (!mod->mod ||
+	     strcmp(q->module, ct->modname)))
+		return false;
+
+	if (q->filename &&
+	    strcmp(q->filename, ct->filename) &&
+	    strcmp(q->filename, kbasename(ct->filename)))
+		return false;
+
+	if (q->function &&
+	    strcmp(q->function, ct->function))
+		return false;
+
+	/* match against the line number range */
+	if (q->match_line &&
+	    (ct->lineno < q->first_line ||
+	     ct->lineno > q->last_line))
+		return false;
+
+	/* match against the class */
+	if (classlen &&
+	    (strncmp(q->class, class, classlen) ||
+	     (class[classlen] && class[classlen] != ':')))
+		return false;
+
+	/* match against the fault index */
+	if (q->match_index &&
+	    (q->cur_index < q->first_index ||
+	     q->cur_index > q->last_index)) {
+		q->cur_index++;
+		return false;
+	}
+
+	q->cur_index++;
+	return true;
+}
-- 
2.37.2.672.g94769d06f0-goog