[PATCH v9 07/10] mbim: Add support for nested fixed arrays in arrays/structs

In some arrays, a nested array can be a fixed array coupled with an
OL-pair, which breaks the existing assumptions of arrays and structs,
leading to wrong data being parsed. Or the parent array can have no
OL-pair in this condition.

For example:
The UICC low-level access data has a struct array, but the array itself
has no OL-pair, instead the OL-pair is of the struct, so the position is
no longer incremented in the array parser so the nested struct can parse
its OL-pair properly. Instead the global iterator position is increased,
so the properties after the OL-pair can be parsed properly.

The method for detecting a fixed array is also flawed, because a nested
array can be fixed, e.g. in the example above, the AID array inside the
struct array is a fixed array, but parsing fails due to it being treated
as a variable array.

Introduce a new argument type to parse fixed nested arrays in order to
solve this. Also remove out_n_elem for arrays, since it can be a
separate field away from the array itself.
---
 drivers/mbimmodem/gprs.c         |  2 +-
 drivers/mbimmodem/mbim-message.c | 27 +++++++++++++++++++--------
 drivers/mbimmodem/sms.c          |  5 +++--
 3 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/drivers/mbimmodem/gprs.c b/drivers/mbimmodem/gprs.c
index 06a50f3d..23953faf 100644
--- a/drivers/mbimmodem/gprs.c
+++ b/drivers/mbimmodem/gprs.c
@@ -175,7 +175,7 @@ static void provisioned_contexts_query_cb(struct mbim_m=
essage *message,
 =09if (mbim_message_get_error(message) !=3D 0)
 =09=09return;
=20
-=09if (!mbim_message_get_arguments(message, "a(u16ysssuu)",
+=09if (!mbim_message_get_arguments(message, "ua(u16ysssuu)",
 =09=09=09=09=09=09&n_contexts, &contexts))
 =09=09return;
=20
diff --git a/drivers/mbimmodem/mbim-message.c b/drivers/mbimmodem/mbim-mess=
age.c
index b6f91c1c..ccda322d 100644
--- a/drivers/mbimmodem/mbim-message.c
+++ b/drivers/mbimmodem/mbim-message.c
@@ -309,7 +309,8 @@ static bool _iter_next_entry_basic(struct mbim_message_=
iter *iter,
 }
=20
 static bool _iter_enter_array(struct mbim_message_iter *iter,
-=09=09=09=09=09struct mbim_message_iter *array)
+=09=09=09=09=09struct mbim_message_iter *array,
+=09=09=09=09=09bool fixed_array)
 {
 =09size_t pos;
 =09uint32_t n_elem;
@@ -322,7 +323,7 @@ static bool _iter_enter_array(struct mbim_message_iter =
*iter,
 =09if (iter->container_type =3D=3D CONTAINER_TYPE_ARRAY && !iter->n_elem)
 =09=09return false;
=20
-=09if (iter->sig_start[iter->sig_pos] !=3D 'a')
+=09if (iter->sig_start[iter->sig_pos] !=3D 'a' && iter->sig_start[iter->si=
g_pos] !=3D 'A')
 =09=09return false;
=20
 =09sig_start =3D iter->sig_start + iter->sig_pos + 1;
@@ -333,7 +334,7 @@ static bool _iter_enter_array(struct mbim_message_iter =
*iter,
 =09 * 1. Element Count, followed by OL_PAIR_LIST
 =09 * 2. Offset, followed by element length or size for raw buffers
 =09 */
-=09fixed =3D is_fixed_size(sig_start, sig_end);
+=09fixed =3D is_fixed_size(sig_start, sig_end) || fixed_array;
=20
 =09if (fixed) {
 =09=09pos =3D align_len(iter->pos, 4);
@@ -351,7 +352,9 @@ static bool _iter_enter_array(struct mbim_message_iter =
*iter,
=20
 =09data =3D _iter_get_data(iter, pos);
 =09n_elem =3D l_get_le32(data);
-=09pos +=3D 4;
+
+=09if (fixed)
+=09=09iter->pos +=3D 4;
=20
 =09if (iter->container_type !=3D CONTAINER_TYPE_ARRAY)
 =09=09iter->sig_pos +=3D sig_end - sig_start + 1;
@@ -445,7 +448,6 @@ static bool message_iter_next_entry_valist(struct mbim_=
message_iter *orig,
 =09struct mbim_message_iter *iter =3D orig;
 =09const char *signature =3D orig->sig_start + orig->sig_pos;
 =09const char *end;
-=09uint32_t *out_n_elem;
 =09struct mbim_message_iter *sub_iter;
 =09struct mbim_message_iter stack[MAX_NESTING];
 =09unsigned int indent =3D 0;
@@ -518,13 +520,22 @@ static bool message_iter_next_entry_valist(struct mbi=
m_message_iter *orig,
 =09=09=09=09iter =3D &stack[indent - 1];
 =09=09=09break;
 =09=09case 'a':
-=09=09=09out_n_elem =3D va_arg(args, uint32_t *);
 =09=09=09sub_iter =3D va_arg(args, void *);
=20
-=09=09=09if (!_iter_enter_array(iter, sub_iter))
+=09=09=09if (!_iter_enter_array(iter, sub_iter, false))
 =09=09=09=09return false;
=20
-=09=09=09*out_n_elem =3D sub_iter->n_elem;
+=09=09=09end =3D _signature_end(signature + 1);
+=09=09=09signature =3D end + 1;
+=09=09=09break;
+=09=09/* Fixed array with an OL pair list, no element count
+=09=09 * TODO: Implement sending fixed arrays to the modem too
+=09=09 */
+=09=09case 'A':
+=09=09=09sub_iter =3D va_arg(args, void *);
+
+=09=09=09if (!_iter_enter_array(iter, sub_iter, true))
+=09=09=09=09return false;
=20
 =09=09=09end =3D _signature_end(signature + 1);
 =09=09=09signature =3D end + 1;
diff --git a/drivers/mbimmodem/sms.c b/drivers/mbimmodem/sms.c
index 1f52ef7e..c0610ef3 100644
--- a/drivers/mbimmodem/sms.c
+++ b/drivers/mbimmodem/sms.c
@@ -211,7 +211,7 @@ static void mbim_parse_sms_read_info(struct mbim_messag=
e *message,
 =09uint32_t status;
 =09uint32_t pdu_len;
=20
-=09if (!mbim_message_get_arguments(message, "ua(uuay)",
+=09if (!mbim_message_get_arguments(message, "uua(uuay)",
 =09=09=09=09=09=09&format, &n_sms, &array))
 =09=09return;
=20
@@ -219,7 +219,8 @@ static void mbim_parse_sms_read_info(struct mbim_messag=
e *message,
 =09=09return;
=20
 =09while (mbim_message_iter_next_entry(&array, &index, &status,
-=09=09=09=09=09=09=09&pdu_len, &bytes)) {
+=09=09=09=09=09=09=09&bytes)) {
+=09=09pdu_len =3D bytes.n_elem;
 =09=09int i =3D 0;
=20
 =09=09/* Ignore Draft (2) and Sent (3) messages */
--=20
2.52.0