Commit 5819e3e0 authored by Peter Wu's avatar Peter Wu Committed by Peter Maydell
Browse files

gdbstub: avoid busy loop while waiting for gdb 

While waiting for a gdb response, or while sending an acknowledgement
there is not much to do, so do not mark the socket as non-blocking to
avoid a busy loop while paused at gdb. This only affects the user-mode
emulation (qemu-arm -g 1234 ./a.out).

Note that this issue was reported before at
https://lists.nongnu.org/archive/html/qemu-devel/2013-02/msg02277.html

.

While at it, close the gdb client fd on EOF or error while reading.

Signed-off-by: default avatarPeter Wu <peter@lekensteyn.nl>
Reviewed-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
parent de5dca1b

gdbstub.c

+7 −5
Original line number Diff line number Diff line
@@ -333,7 +333,7 @@ static int get_char(GDBState *s) 
        if (ret < 0) {

            if (errno == ECONNRESET)

                s->fd = -1;

            if (errno != EINTR && errno != EAGAIN)

            if (errno != EINTR)

                return -1;

        } else if (ret == 0) {

            close(s->fd);
@@ -394,7 +394,7 @@ static void put_buffer(GDBState *s, const uint8_t *buf, int len) 
    while (len > 0) {

        ret = send(s->fd, buf, len, 0);

        if (ret < 0) {

            if (errno != EINTR && errno != EAGAIN)

            if (errno != EINTR)

                return;

        } else {

            buf += ret;
@@ -1543,9 +1543,13 @@ gdb_handlesig(CPUState *cpu, int sig) 
            for (i = 0; i < n; i++) {

                gdb_read_byte(s, buf[i]);

            }

        } else if (n == 0 || errno != EAGAIN) {

        } else {

            /* XXX: Connection closed.  Should probably wait for another

               connection before continuing.  */

            if (n == 0) {

                close(s->fd);

            }

            s->fd = -1;

            return sig;

        }

    }
@@ -1600,8 +1604,6 @@ static void gdb_accept(void) 
    gdb_has_xml = false;



    gdbserver_state = s;



    fcntl(fd, F_SETFL, O_NONBLOCK);

}



static int gdbserver_open(int port)