fileinfo: Obey POSIX in pattern conversion

Signed-off-by: Anatol Belski <[email protected]>

Author: weltling

ext/fileinfo/libmagic/softmagic.c

@@ -2025,6 +2025,7 @@ public zend_string* convert_libmagic_pattern(const char *val, size_t len, uint32
 	j = 0;
 	ZSTR_VAL(t)[j++] = '~';
 
+	bool add_newline = false;
 	for (i = 0; i < len; i++, j++) {
 		switch (val[i]) {
 			case '~':
@@ -2037,6 +2038,21 @@ public zend_string* convert_libmagic_pattern(const char *val, size_t len, uint32
 				ZSTR_VAL(t)[j++] = '0';
 				ZSTR_VAL(t)[j] = '0';
 				break;
+			/* If POSIX regex class negates, make sure possible '\n' is taken into
+			   account. For example "[^;]" is converted to "[^;]\n?" to obey POSIX. */
+			case '^':
+				ZSTR_VAL(t)[j] = val[i];
+				add_newline = (j >= 1 && '[' == ZSTR_VAL(t)[j-1]);
+				break;
+			case ']':
+				ZSTR_VAL(t)[j] = val[i];
+				if (add_newline) {
+					t = zend_string_realloc(t, ZSTR_LEN(t) + 3, GC_TYPE_INFO(t) & IS_STR_PERSISTENT);
+					ZSTR_VAL(t)[j++] = '\\';
+					ZSTR_VAL(t)[j++] = 'n';
+					ZSTR_VAL(t)[j++] = '?';
+					add_newline = false;
+				}
 			default:
 				ZSTR_VAL(t)[j] = val[i];
 				break;