stlink (tcp): manage scattered stlink-server responses

detected in ubuntu 20.04
sometimes, the stlink-server response could be segmented on multiple
packets.

this causes stlink_tcp_send_cmd to fail with the following msg:
Error: failed to receive USB CMD response
because the received_size < expected size

to fix the issue, do recv in a loop till all data is received
or timeout is reached.

Change-Id: I46cc60c231b4cc52f150ead268f843bc60c41149
Signed-off-by: Tarek BOCHKATI <tarek.bouchkati@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/6671
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
Tested-by: jenkins

diff --git a/src/jtag/drivers/stlink_usb.c b/src/jtag/drivers/stlink_usb.c
index b51a0c2bacd23d51232657e510ed3c0848c54d48..87e6ddc20f3066aef72b93407acd71aa04c72527 100644 (file)
--- a/src/jtag/drivers/stlink_usb.c
+++ b/src/jtag/drivers/stlink_usb.c
@@ -37,6 +37,7 @@
 #include <helper/binarybuffer.h>
 #include <helper/bits.h>
 #include <helper/system.h>
+#include <helper/time_support.h>
 #include <jtag/interface.h>
 #include <jtag/hla/hla_layout.h>
 #include <jtag/hla/hla_transport.h>
@@ -926,17 +927,35 @@ static int stlink_tcp_send_cmd(void *handle, int send_size, int recv_size, bool
                return ERROR_FAIL;
        }
 
-       keep_alive();
-
        /* read the TCP response */
-       int received_size = recv(h->tcp_backend_priv.fd, (void *)h->tcp_backend_priv.recv_buf, recv_size, 0);
-       if (received_size != recv_size) {
-               LOG_ERROR("failed to receive USB CMD response");
-               if (received_size == -1)
+       int retval = ERROR_OK;
+       int remaining_bytes = recv_size;
+       uint8_t *recv_buf = h->tcp_backend_priv.recv_buf;
+       const int64_t timeout = timeval_ms() + 1000; /* 1 second */
+
+       while (remaining_bytes > 0) {
+               if (timeval_ms() > timeout) {
+                       LOG_DEBUG("received size %d (expected %d)", recv_size - remaining_bytes, recv_size);
+                       retval = ERROR_TIMEOUT_REACHED;
+                       break;
+               }
+
+               keep_alive();
+               int received = recv(h->tcp_backend_priv.fd, (void *)recv_buf, remaining_bytes, 0);
+
+               if (received == -1) {
                        LOG_DEBUG("socket recv error: %s (errno %d)", strerror(errno), errno);
-               else
-                       LOG_DEBUG("received size %d (expected %d)", received_size, recv_size);
-               return ERROR_FAIL;
+                       retval = ERROR_FAIL;
+                       break;
+               }
+
+               recv_buf += received;
+               remaining_bytes -= received;
+       }
+
+       if (retval != ERROR_OK) {
+               LOG_ERROR("failed to receive USB CMD response");
+               return retval;
        }
 
        if (check_tcp_status) {