1 files changed, 148 insertions, 0 deletions
diff --git a/src/libsystemd/sd-bus/bus-signature.c b/src/libsystemd/sd-bus/bus-signature.c
new file mode 100644
index 0000000..bd0842f
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-signature.c
@@ -0,0 +1,148 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <util.h>
+
+#include "sd-bus.h"
+
+#include "bus-signature.h"
+#include "bus-type.h"
+
+static int signature_element_length_internal(
+                const char *s,
+                bool allow_dict_entry,
+                unsigned array_depth,
+                unsigned struct_depth,
+                size_t *l) {
+
+        int r;
+
+        if (!s)
+                return -EINVAL;
+
+        assert(l);
+
+        if (bus_type_is_basic(*s) || *s == SD_BUS_TYPE_VARIANT) {
+                *l = 1;
+                return 0;
+        }
+
+        if (*s == SD_BUS_TYPE_ARRAY) {
+                size_t t;
+
+                if (array_depth >= 32)
+                        return -EINVAL;
+
+                r = signature_element_length_internal(s + 1, true, array_depth+1, struct_depth, &t);
+                if (r < 0)
+                        return r;
+
+                *l = t + 1;
+                return 0;
+        }
+
+        if (*s == SD_BUS_TYPE_STRUCT_BEGIN) {
+                const char *p = s + 1;
+
+                if (struct_depth >= 32)
+                        return -EINVAL;
+
+                while (*p != SD_BUS_TYPE_STRUCT_END) {
+                        size_t t;
+
+                        r = signature_element_length_internal(p, false, array_depth, struct_depth+1, &t);
+                        if (r < 0)
+                                return r;
+
+                        p += t;
+                }
+
+                if (p - s < 2)
+                        /* D-Bus spec: Empty structures are not allowed; there
+                         * must be at least one type code between the parentheses.
+                         */
+                        return -EINVAL;
+
+                *l = p - s + 1;
+                return 0;
+        }
+
+        if (*s == SD_BUS_TYPE_DICT_ENTRY_BEGIN && allow_dict_entry) {
+                const char *p = s + 1;
+                unsigned n = 0;
+
+                if (struct_depth >= 32)
+                        return -EINVAL;
+
+                while (*p != SD_BUS_TYPE_DICT_ENTRY_END) {
+                        size_t t;
+
+                        if (n == 0 && !bus_type_is_basic(*p))
+                                return -EINVAL;
+
+                        r = signature_element_length_internal(p, false, array_depth, struct_depth+1, &t);
+                        if (r < 0)
+                                return r;
+
+                        p += t;
+                        n++;
+                }
+
+                if (n != 2)
+                        return -EINVAL;
+
+                *l = p - s + 1;
+                return 0;
+        }
+
+        return -EINVAL;
+}
+
+int signature_element_length(const char *s, size_t *l) {
+        return signature_element_length_internal(s, true, 0, 0, l);
+}
+
+bool signature_is_single(const char *s, bool allow_dict_entry) {
+        int r;
+        size_t t;
+
+        if (!s)
+                return false;
+
+        r = signature_element_length_internal(s, allow_dict_entry, 0, 0, &t);
+        if (r < 0)
+                return false;
+
+        return s[t] == 0;
+}
+
+bool signature_is_pair(const char *s) {
+
+        if (!s)
+                return false;
+
+        if (!bus_type_is_basic(*s))
+                return false;
+
+        return signature_is_single(s + 1, false);
+}
+
+bool signature_is_valid(const char *s, bool allow_dict_entry) {
+        const char *p;
+        int r;
+
+        if (!s)
+                return false;
+
+        p = s;
+        while (*p) {
+                size_t t;
+
+                r = signature_element_length_internal(p, allow_dict_entry, 0, 0, &t);
+                if (r < 0)
+                        return false;
+
+                p += t;
+        }
+
+        return p - s <= SD_BUS_MAXIMUM_SIGNATURE_LENGTH;
+}