static int c_variant_write_one(CVariant *cv, char basic, const void *arg, size_t n_arg) {
CVariantLevel *level;
CVariantType info;
void *front;
int r;
assert(n_arg > 0);
level = cv->state->levels + cv->state->i_levels;
if (_unlikely_(level->n_type < 1))
return c_variant_poison(cv, -EBADRQC);
r = c_variant_signature_next(level->type, level->n_type, &info);
assert(r == 1);
r = c_variant_append(cv, basic, &info, 0, n_arg, &front, 0, NULL);
if (r < 0)
return r;
memcpy(front, arg, n_arg);
return 0;
}
static int c_variant_insert_one(CVariant *cv, const char *type, const struct iovec *vecs, size_t n_vecs, size_t size) {
CVariantLevel *level;
CVariantType info;
size_t n_type, i, idx;
struct iovec *v;
uint64_t frame;
int r;
level = cv->state->levels + cv->state->i_levels;
if (_unlikely_(level->n_type < 1))
return c_variant_poison(cv, -EBADRQC);
r = c_variant_signature_next(level->type, level->n_type, &info);
assert(r == 1);
n_type = strlen(type);
if (_unlikely_(n_type != info.n_type || strncmp(type, info.type, n_type)))
return c_variant_poison(cv, -EBADRQC);
if (_unlikely_(info.size > 0 && size != info.size))
return c_variant_poison(cv, -EBADMSG);
r = c_variant_append(cv, *type, &info, n_vecs + 1, 0, NULL, 0, NULL);
if (r < 0)
return r;
/* make sure there are at least 'n_vecs + 1' unused vectors */
assert(cv->n_vecs - level->v_front - level->v_tail - 2U >= n_vecs + 1U);
/*
* Clip the current front and prepare the next vector with the
* remaining buffer space. Then insert the requested vectors in between
* both and verify alignment restrictions.
*/
v = cv->vecs + level->v_front;
v[n_vecs + 1].iov_base = (char *)v->iov_base + level->i_front;
v[n_vecs + 1].iov_len = v->iov_len - level->i_front;
v->iov_len = level->i_front;
for (i = 0; i < n_vecs; ++i) {
idx = level->v_front + i + 1;
if (((char *)(cv->vecs + cv->n_vecs))[idx]) {
((char *)(cv->vecs + cv->n_vecs))[idx] = false;
free((cv->vecs + idx)->iov_base);
}
cv->vecs[idx] = vecs[i];
}
level->v_front += n_vecs + 1;
level->i_front = 0;
level->offset += size;
/* see c_variant_end_one(); we have to update the framing offset */
if (info.size < 1) {
switch (level->enclosing) {
case C_VARIANT_TUPLE_OPEN:
case C_VARIANT_PAIR_OPEN:
/* last element never stores framing offsets */
if (level->n_type < 1)
break;
/* fallthrough */
case C_VARIANT_ARRAY:
assert(level->i_tail >= 8);
assert(!(level->i_tail & 7));
v = cv->vecs + cv->n_vecs - level->v_tail - 1;
frame = level->offset;
memcpy((char *)v->iov_base + level->i_tail - 8, &frame, 8);
break;
}
}
return 0;
}
static int c_variant_begin_one(CVariant *cv, char container, const char *variant) {
CVariantLevel *next, *level;
CVariantType info;
size_t n_tail;
void *tail;
int r;
r = c_variant_ensure_level(cv);
if (r < 0)
return r;
if (container == C_VARIANT_VARIANT)
n_tail = strlen(variant);
else
n_tail = 0;
level = cv->state->levels + cv->state->i_levels;
if (_unlikely_(level->n_type < 1))
return c_variant_poison(cv, -EBADRQC);
r = c_variant_signature_next(level->type, level->n_type, &info);
assert(r == 1);
r = c_variant_append(cv, container, &info, 0, 0, NULL, n_tail, &tail);
if (r < 0)
return r;
c_variant_push_level(cv);
next = cv->state->levels + cv->state->i_levels;
next->size = info.size;
next->i_tail = level->i_tail;
next->v_tail = level->v_tail;
/* wordsize is unused */
next->enclosing = container;
next->v_front = level->v_front;
next->i_front = level->i_front;
next->index = 0;
next->offset = 0;
switch (container) {
case C_VARIANT_VARIANT:
memcpy(tail, variant, n_tail);
next->i_tail += n_tail;
next->n_type = n_tail;
next->index = n_tail;
next->type = tail;
break;
case C_VARIANT_MAYBE:
case C_VARIANT_ARRAY:
next->n_type = info.n_type - 1;
next->type = info.type + 1;
break;
case C_VARIANT_TUPLE_OPEN:
case C_VARIANT_PAIR_OPEN:
next->n_type = info.n_type - 2;
next->type = info.type + 1;
break;
default:
assert(0);
break;
}
return 0;
}
static void test_signature_api(void) {
CVariantType t;
int r;
/*
* Verify that we never read more data from the signature than
* requested by the caller. Hence, this call should never see the
* invalid '$' element.
*/
r = c_variant_signature_next("$foobar", 0, &t);
assert(r == 0);
assert(t.alignment == 0);
assert(t.size == 0);
assert(t.bound_size == 0);
assert(t.n_levels == 0);
assert(t.n_type == 0);
/*
* Verify that we never look ahead of a parsed type. That is, parsing
* the valid element 'b' should return before looking at the invalid
* element '$' ahead.
* But if we then strip it (that is, we continue after the parsed
* element), it should immediately fail but leave 't' untouched.
*/
r = c_variant_signature_next("b$foobar", 8, &t);
assert(r == 1);
assert(t.alignment == 0);
assert(t.size == 1);
assert(t.bound_size == 0);
assert(t.n_levels == 0);
assert(t.n_type == 1);
assert(!strncmp(t.type, "b", t.n_type));
r = c_variant_signature_next(t.type + t.n_type, 8 - t.n_type, &t);
assert(r < 0);
assert(r == -EMEDIUMTYPE);
/* @t must not have been touched! */
assert(t.alignment == 0);
assert(t.size == 1);
assert(t.bound_size == 0);
assert(t.n_levels == 0);
assert(t.n_type == 1);
assert(!strncmp(t.type, "b", t.n_type));
/*
* Make sure an inappropriately sized signature will result in an
* immediate error without the data being looked at.
* This is not explicitly part of the *ABI*, but reasonable enough to
* test for.
*/
r = c_variant_signature_next(NULL, SIZE_MAX, &t);
assert(r < 0);
assert(r == -EMSGSIZE);
/*
* Make sure API-types are rejected in type-strings. This includes
* anything that is not a valid element.
*/
r = c_variant_signature_next("r", 1, &t);
assert(r < 0);
assert(r == -EMEDIUMTYPE);
r = c_variant_signature_next("e", 1, &t);
assert(r < 0);
assert(r == -EMEDIUMTYPE);
r = c_variant_signature_next("?", 1, &t);
assert(r < 0);
assert(r == -EMEDIUMTYPE);
r = c_variant_signature_next("*", 1, &t);
assert(r < 0);
assert(r == -EMEDIUMTYPE);
}