rigol-ds: Fix partial read handling in header parser.

diff --git a/hardware/rigol-ds/protocol.c b/hardware/rigol-ds/protocol.c
index 2df69c56d8e9cedaf4e99916b0cca13e6c9b3788..de91e0709a877db19e230e54c8239216f5f19f25 100644 (file)
--- a/hardware/rigol-ds/protocol.c
+++ b/hardware/rigol-ds/protocol.c
@@ -401,49 +401,71 @@ SR_PRIV int rigol_ds_channel_start(const struct sr_dev_inst *sdi)
                                return SR_ERR;
                        if (rigol_ds_config_set(sdi, ":WAV:BEG") != SR_OK)
                                return SR_ERR;
-                       rigol_ds_set_wait_event(devc, WAIT_BLOCK);
-               } else
-                       rigol_ds_set_wait_event(devc, WAIT_NONE);
+               }
        }
 
+       rigol_ds_set_wait_event(devc, WAIT_BLOCK);
+
        devc->num_channel_bytes = 0;
+       devc->num_header_bytes = 0;
        devc->num_block_bytes = 0;
 
        return SR_OK;
 }
 
 /* Read the header of a data block */
-static int rigol_ds_read_header(struct sr_scpi_dev_inst *scpi)
+static int rigol_ds_read_header(struct sr_dev_inst *sdi)
 {
-       char start[3], length[10];
-       int len, tmp;
-
-       /* Read the hashsign and length digit. */
-       tmp = sr_scpi_read_data(scpi, start, 2);
-       start[2] = '\0';
-       if (tmp != 2) {
-               sr_err("Failed to read first two bytes of data block header.");
-               return -1;
+       struct sr_scpi_dev_inst *scpi = sdi->conn;
+       struct dev_context *devc = sdi->priv;
+       char *buf = (char *) devc->buffer;
+       int len;
+       int tmp;
+
+       /* Try to read the hashsign and length digit. */
+       if (devc->num_header_bytes < 2) {
+               tmp = sr_scpi_read_data(scpi, buf + devc->num_header_bytes,
+                               2 - devc->num_header_bytes);
+               if (tmp < 0) {
+                       sr_err("Read error while reading data header.");
+                       return SR_ERR;
+               }
+               devc->num_header_bytes += tmp;
        }
-       if (start[0] != '#' || !isdigit(start[1]) || start[1] == '0') {
-               sr_err("Received invalid data block header start '%s'.", start);
-               return -1;
+
+       if (devc->num_header_bytes < 2)
+               return 0;
+
+       if (buf[0] != '#' || !isdigit(buf[1]) || buf[1] == '0') {
+               sr_err("Received invalid data block header '%c%c'.", buf[0], buf[1]);
+               return SR_ERR;
        }
-       len = atoi(start + 1);
 
-       /* Read the data length. */
-       tmp = sr_scpi_read_data(scpi, length, len);
-       length[len] = '\0';
-       if (tmp != len) {
-               sr_err("Failed to read %d bytes of data block length.", len);
-               return -1;
+       len = buf[1] - '0';
+
+       /* Try to read the length. */
+       if (devc->num_header_bytes < 2 + len) {
+               tmp = sr_scpi_read_data(scpi, buf + devc->num_header_bytes,
+                               2 + len - devc->num_header_bytes);
+               if (tmp < 0) {
+                       sr_err("Read error while reading data header.");
+                       return SR_ERR;
+               }
+               devc->num_header_bytes += tmp;
        }
-       if (parse_int(length, &len) != SR_OK) {
-               sr_err("Received invalid data block length '%s'.", length);
+
+       if (devc->num_header_bytes < 2 + len)
+               return 0;
+
+       /* Read the data length. */
+       buf[2 + len] = '\0';
+
+       if (parse_int(buf + 2, &len) != SR_OK) {
+               sr_err("Received invalid data block length '%s'.", buf + 2);
                return -1;
        }
 
-       sr_dbg("Received data block header: %s%s -> block length %d", start, length, len);
+       sr_dbg("Received data block header: '%s' -> block length %d", buf, len);
 
        return len;
 }
@@ -512,9 +534,17 @@ SR_PRIV int rigol_ds_receive(int fd, int revents, void *cb_data)
 
                        if (devc->format == FORMAT_IEEE488_2) {
                                sr_dbg("New block header expected");
-                               len = rigol_ds_read_header(scpi);
-                               if (len == -1)
+                               len = rigol_ds_read_header(sdi);
+                               if (len == 0)
+                                       /* Still reading the header. */
+                                       return TRUE;
+                               if (len == -1) {
+                                       sr_err("Read error, aborting capture.");
+                                       packet.type = SR_DF_FRAME_END;
+                                       sr_session_send(cb_data, &packet);
+                                       sdi->driver->dev_acquisition_stop(sdi, cb_data);
                                        return TRUE;
+                               }
                                /* At slow timebases in live capture the DS2072
                                 * sometimes returns "short" data blocks, with
                                 * apparently no way to get the rest of the data.
@@ -590,6 +620,7 @@ SR_PRIV int rigol_ds_receive(int fd, int revents, void *cb_data)
                        }
                        if (devc->format == FORMAT_IEEE488_2) {
                                /* Prepare for possible next block */
+                               devc->num_header_bytes = 0;
                                devc->num_block_bytes = 0;
                                if (devc->data_source != DATA_SOURCE_LIVE)
                                        rigol_ds_set_wait_event(devc, WAIT_BLOCK);

diff --git a/hardware/rigol-ds/protocol.h b/hardware/rigol-ds/protocol.h
index 269e0f0f4677d72690fd8b696310478ffaadead9..2fe8d8653e99a80008f1a23a9f527a3600790de3 100644 (file)
--- a/hardware/rigol-ds/protocol.h
+++ b/hardware/rigol-ds/protocol.h
@@ -131,6 +131,8 @@ struct dev_context {
        GSList *channel_entry;
        /* Number of bytes received for current channel. */
        uint64_t num_channel_bytes;
+       /* Number of bytes of block header read */
+       uint64_t num_header_bytes;
        /* Number of bytes in current data block, if 0 block header expected */
        uint64_t num_block_bytes;
        /* Number of data block bytes already read */