Prevent reading past end of OLS hardware buffer.

[libsigrok.git] / hardware / openbench-logic-sniffer / ols.c

diff --git a/hardware/openbench-logic-sniffer/ols.c b/hardware/openbench-logic-sniffer/ols.c
index e7daa016a9e6eef9ce9eba35c2e158c8b83a6d7e..0f445a39f525d9c99175bc7ea3f0d292c032ddf6 100644 (file)
--- a/hardware/openbench-logic-sniffer/ols.c
+++ b/hardware/openbench-logic-sniffer/ols.c
@@ -592,6 +592,9 @@ static int hw_set_configuration(int device_index, int capability, void *value)
                tmp_u64 = value;
                if (*tmp_u64 < MIN_NUM_SAMPLES)
                        return SR_ERR;
+               if (*tmp_u64 > ols->max_samples) 
+                       sr_warn("ols: sample limit exceeds hw max");
+
                ols->limit_samples = *tmp_u64;
                sr_info("ols: sample limit %" PRIu64, ols->limit_samples);
                ret = SR_OK;
@@ -706,6 +709,7 @@ static int receive_data(int fd, int revents, void *session_data)
                                /* No compression. */
                                buffer = ols->sample;
                                buflen = 4;
+                               ols->num_samples++;
                        }
 
                        if (num_channels < 4) {
@@ -767,7 +771,8 @@ static int receive_data(int fd, int revents, void *session_data)
                                packet.payload = &logic;
                                logic.length = ols->trigger_at * 4;
                                logic.unitsize = 4;
-                               logic.data = ols->raw_sample_buf;
+                               logic.data = ols->raw_sample_buf + 
+                                       (ols->limit_samples - ols->num_samples) * 4;
                                sr_session_bus(session_data, &packet);
                        }
 
@@ -780,21 +785,23 @@ static int receive_data(int fd, int revents, void *session_data)
                        /* send post-trigger samples */
                        packet.type = SR_DF_LOGIC;
                        packet.timeoffset = ols->trigger_at * ols->period_ps;
-                       packet.duration = (ols->limit_samples - ols->trigger_at) * ols->period_ps;
+                       packet.duration = (ols->num_samples - ols->trigger_at) * ols->period_ps;
                        packet.payload = &logic;
-                       logic.length = (ols->limit_samples * 4) - (ols->trigger_at * 4);
+                       logic.length = (ols->num_samples * 4) - (ols->trigger_at * 4);
                        logic.unitsize = 4;
-                       logic.data = ols->raw_sample_buf + ols->trigger_at * 4;
+                       logic.data = ols->raw_sample_buf + ols->trigger_at * 4 +
+                               (ols->limit_samples - ols->num_samples) * 4;
                        sr_session_bus(session_data, &packet);
                } else {
                        /* no trigger was used */
                        packet.type = SR_DF_LOGIC;
                        packet.timeoffset = 0;
-                       packet.duration = ols->limit_samples * ols->period_ps;
+                       packet.duration = ols->num_samples * ols->period_ps;
                        packet.payload = &logic;
-                       logic.length = ols->limit_samples * 4;
+                       logic.length = ols->num_samples * 4;
                        logic.unitsize = 4;
-                       logic.data = ols->raw_sample_buf;
+                       logic.data = ols->raw_sample_buf +
+                               (ols->limit_samples - ols->num_samples) * 4;
                        sr_session_bus(session_data, &packet);
                }
                g_free(ols->raw_sample_buf);
@@ -802,7 +809,7 @@ static int receive_data(int fd, int revents, void *session_data)
                serial_flush(fd);
                serial_close(fd);
                packet.type = SR_DF_END;
-               packet.timeoffset = ols->limit_samples * ols->period_ps;
+               packet.timeoffset = ols->num_samples * ols->period_ps;
                packet.duration = 0;
                sr_session_bus(session_data, &packet);
        }
@@ -820,6 +827,7 @@ static int hw_start_acquisition(int device_index, gpointer session_data)
        uint32_t data;
        uint16_t readcount, delaycount;
        uint8_t changrp_mask;
+       int num_channels;
        int i;
 
        if (!(sdi = sr_get_device_instance(device_instances, device_index)))
@@ -830,7 +838,24 @@ static int hw_start_acquisition(int device_index, gpointer session_data)
        if (sdi->status != SR_ST_ACTIVE)
                return SR_ERR;
 
-       readcount = ols->limit_samples / 4;
+       /*
+        * Enable/disable channel groups in the flag register according to the
+        * probe mask.  Calculate this here, because num_channels is needed
+        * to limit readcount.
+        */
+       changrp_mask = 0;
+       num_channels = 0;
+       for (i = 0; i < 4; i++) {
+               if (ols->probe_mask & (0xff << (i * 8))) {
+                       changrp_mask |= (1 << i);
+                       num_channels++;
+               }
+       }
+
+       /* Limit readcount to prevent reading past the end of the hardware
+        * buffer.
+        */
+       readcount = MIN(ols->max_samples / num_channels, ols->limit_samples) / 4;
 
        memset(trigger_config, 0, 16);
        trigger_config[ols->num_stages - 1] |= 0x08;
@@ -903,16 +928,6 @@ static int hw_start_acquisition(int device_index, gpointer session_data)
        if (send_longcommand(sdi->serial->fd, CMD_CAPTURE_SIZE, reverse16(data)) != SR_OK)
                return SR_ERR;
 
-       /*
-        * Enable/disable channel groups in the flag register according to the
-        * probe mask.
-        */
-       changrp_mask = 0;
-       for (i = 0; i < 4; i++) {
-               if (ols->probe_mask & (0xff << (i * 8)))
-                       changrp_mask |= (1 << i);
-       }
-
        /* The flag register wants them here, and 1 means "disable channel". */
        ols->flag_reg |= ~(changrp_mask << 2) & 0x3c;
        ols->flag_reg |= FLAG_FILTER;