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: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Peter Wu 2016-06-05 16:35:48 +02:00 committed by Peter Maydell
parent de5dca1b79
commit 5819e3e072

View File

@ -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)