Fix character "@" added at end of received messages

If 7 bit message encoded on 8 bit cells has one last bit occupying
whole byte it need to be padded with 7 zero bits. To not mistake
these last 7 bits with a character with code 0 (@) we need to check
length from User Data Length field and not rely on actual length
of received data. An example can be message "abcdefg" encoded
as "61 f1 98 5c 36 9f 01", it is decoded as "abcdefg@".

Signed-off-by: SÅ‚awomir Demeszko <s.demeszko@wireless-instruments.com>

diff --git a/commands-wms.c b/commands-wms.c
index 74f50aa9bc135244cc7c39b469fb257b2e963f69..47d4d768f4cb36c795c9f2414c90bf3f35a2be35 100644 (file)
--- a/commands-wms.c
+++ b/commands-wms.c
@@ -1,5 +1,8 @@
 #include "qmi-message.h"
 
+#define MIN(a,b) (((a)<(b))?(a):(b))
+#define CEILDIV(x,y) (((x) + (y) - 1) / (y))
+
 static void cmd_wms_list_messages_cb(struct qmi_dev *qmi, struct qmi_request *req, struct qmi_msg *msg)
 {
        struct qmi_wms_list_messages_response res;
@@ -191,8 +194,9 @@ static int decode_udh(const unsigned char *data)
 
 static void decode_7bit_field(char *name, const unsigned char *data, int data_len, int bit_offset)
 {
-       char *dest = blobmsg_alloc_string_buffer(&status, name, 3 * (data_len * 8 / 7) + 2);
-       pdu_decode_7bit_str(dest, data, data_len, bit_offset);
+       char *dest = blobmsg_alloc_string_buffer(&status, name, 3 * data_len + 2);
+       pdu_decode_7bit_str(dest, data, CEILDIV(data_len * 7, 8), bit_offset);
+       dest[data_len] = 0;
        blobmsg_add_string_buffer(&status);
 }
 
@@ -366,12 +370,13 @@ static void cmd_wms_get_message_cb(struct qmi_dev *qmi, struct qmi_request *req,
                data += 7;
        }
 
-       data++;
+       int message_len = *(data++);
+       int udh_len = 0;
        int bit_offset = 0;
 
        /* User Data Header */
        if (first & 0x40) {
-               int udh_len = decode_udh(data);
+               udh_len = decode_udh(data);
                data += udh_len;
                bit_offset = udh_len % 7;
                }
@@ -382,15 +387,19 @@ static void cmd_wms_get_message_cb(struct qmi_dev *qmi, struct qmi_request *req,
        switch(dcs & 0x0c) {
                case 0x00:
                        /* 7 bit GSM alphabet */
-                       decode_7bit_field("text", data, end - data, bit_offset);
+                       message_len = message_len - CEILDIV(udh_len * 8, 7);
+                       message_len = MIN(message_len, CEILDIV((end - data) * 8, 7));
+                       decode_7bit_field("text", data, message_len, bit_offset);
                        break;
                case 0x04:
                        /* 8 bit data */
-                       blobmsg_add_hex(&status, "data", data, end - data);
+                       message_len = MIN(message_len - udh_len, end - data);
+                       blobmsg_add_hex(&status, "data", data, message_len);
                        break;
                case 0x08:
                        /* 16 bit UCS-2 string */
-                       blobmsg_add_hex(&status, "ucs-2", data, end - data);
+                       message_len = MIN(message_len - udh_len, end - data);
+                       blobmsg_add_hex(&status, "ucs-2", data, message_len);
                        break;
                default:
                        goto error;