apparmor: dfa move character match into a macro

Signed-off-by: John Johansen <john.johansen@canonical.com>

security/apparmor/match.c

@@ -329,6 +329,18 @@ struct aa_dfa *aa_dfa_unpack(void *blob, size_t size, int flags)
 	return ERR_PTR(error);
 }
 
+#define match_char(state, def, base, next, check, C)	\
+do {							\
+	u32 b = (base)[(state)];			\
+	unsigned int pos = base_idx(b) + (C);		\
+	if ((check)[pos] != (state)) {			\
+		(state) = (def)[(state)];		\
+		break;					\
+	}						\
+	(state) = (next)[pos];				\
+	break;						\
+} while (1)
+
 /**
  * aa_dfa_match_len - traverse @dfa to find state @str stops at
  * @dfa: the dfa to match @str against  (NOT NULL)
@@ -352,7 +364,7 @@ unsigned int aa_dfa_match_len(struct aa_dfa *dfa, unsigned int start,
 	u32 *base = BASE_TABLE(dfa);
 	u16 *next = NEXT_TABLE(dfa);
 	u16 *check = CHECK_TABLE(dfa);
-	unsigned int state = start, pos;
+	unsigned int state = start;
 
 	if (state == 0)
 		return 0;
@@ -361,23 +373,13 @@ unsigned int aa_dfa_match_len(struct aa_dfa *dfa, unsigned int start,
 	if (dfa->tables[YYTD_ID_EC]) {
 		/* Equivalence class table defined */
 		u8 *equiv = EQUIV_TABLE(dfa);
-		/* default is direct to next state */
-		for (; len; len--) {
-			pos = base_idx(base[state]) + equiv[(u8) *str++];
-			if (check[pos] == state)
-				state = next[pos];
-			else
-				state = def[state];
-		}
+		for (; len; len--)
+			match_char(state, def, base, next, check,
+				   equiv[(u8) *str++]);
 	} else {
 		/* default is direct to next state */
-		for (; len; len--) {
-			pos = base_idx(base[state]) + (u8) *str++;
-			if (check[pos] == state)
-				state = next[pos];
-			else
-				state = def[state];
-		}
+		for (; len; len--)
+			match_char(state, def, base, next, check, (u8) *str++);
 	}
 
 	return state;
@@ -402,7 +404,7 @@ unsigned int aa_dfa_match(struct aa_dfa *dfa, unsigned int start,
 	u32 *base = BASE_TABLE(dfa);
 	u16 *next = NEXT_TABLE(dfa);
 	u16 *check = CHECK_TABLE(dfa);
-	unsigned int state = start, pos;
+	unsigned int state = start;
 
 	if (state == 0)
 		return 0;
@@ -412,22 +414,13 @@ unsigned int aa_dfa_match(struct aa_dfa *dfa, unsigned int start,
 		/* Equivalence class table defined */
 		u8 *equiv = EQUIV_TABLE(dfa);
 		/* default is direct to next state */
-		while (*str) {
-			pos = base_idx(base[state]) + equiv[(u8) *str++];
-			if (check[pos] == state)
-				state = next[pos];
-			else
-				state = def[state];
-		}
+		while (*str)
+			match_char(state, def, base, next, check,
+				   equiv[(u8) *str++]);
 	} else {
 		/* default is direct to next state */
-		while (*str) {
-			pos = base_idx(base[state]) + (u8) *str++;
-			if (check[pos] == state)
-				state = next[pos];
-			else
-				state = def[state];
-		}
+		while (*str)
+			match_char(state, def, base, next, check, (u8) *str++);
 	}
 
 	return state;
@@ -450,27 +443,14 @@ unsigned int aa_dfa_next(struct aa_dfa *dfa, unsigned int state,
 	u32 *base = BASE_TABLE(dfa);
 	u16 *next = NEXT_TABLE(dfa);
 	u16 *check = CHECK_TABLE(dfa);
-	unsigned int pos;
 
 	/* current state is <state>, matching character *str */
 	if (dfa->tables[YYTD_ID_EC]) {
 		/* Equivalence class table defined */
 		u8 *equiv = EQUIV_TABLE(dfa);
-		/* default is direct to next state */
-
-		pos = base_idx(base[state]) + equiv[(u8) c];
-		if (check[pos] == state)
-			state = next[pos];
-		else
-			state = def[state];
-	} else {
-		/* default is direct to next state */
-		pos = base_idx(base[state]) + (u8) c;
-		if (check[pos] == state)
-			state = next[pos];
-		else
-			state = def[state];
-	}
+		match_char(state, def, base, next, check, equiv[(u8) c]);
+	} else
+		match_char(state, def, base, next, check, (u8) c);
 
 	return state;
 }