On 07/09/2014 10:08 PM, Jeremy White wrote:
> This allows the vdagent to be used in the Xsetup phase of an xdm session;
> otherwise, it's X11 connection fails because of the greeter display grab.
>
> The issue is that we daemonize before attempting the X connection.
> We then immediately exit the main process; xdm then goes on to invoke the
> greeter which performs an exclusive grab on the X server, so the child
> connection fails.
>
> The change is to have the main process wait for up to 10 seconds for an 'all
> clear'
> message from the client. This lets us return a correct status on a real X
> error, as well as letting our child successfully connect to the X server.
>
> Signed-off-by: Jeremy White <jwh...@codeweavers.com>
> ---
Pushed together with the previous two v1 patches.
> src/vdagent.c | 50 ++++++++++++++++++++++++++++++++++++++++++++------
> 1 file changed, 44 insertions(+), 6 deletions(-)
>
> diff --git a/src/vdagent.c b/src/vdagent.c
> index d7f7aba..905ff5b 100644
> --- a/src/vdagent.c
> +++ b/src/vdagent.c
> @@ -35,6 +35,7 @@
> #include <sys/stat.h>
> #include <spice/vd_agent.h>
> #include <glib.h>
> +#include <poll.h>
>
> #include "udscs.h"
> #include "vdagentd-proto.h"
> @@ -151,9 +152,34 @@ static void quit_handler(int sig)
> quit = 1;
> }
>
> -void daemonize(void)
> +/* When we daemonize, it is useful to have the main process
> + wait to make sure the X connection worked. We wait up
> + to 10 seconds to get an 'all clear' from the child
> + before we exit. If we don't, we're able to exit with a
> + status that indicates an error occured */
> +void wait_and_exit(int s)
> {
> - int x, retval = 0;
> + char buf[4];
> + struct pollfd p;
> + p.fd = s;
> + p.events = POLLIN;
> +
> + if (poll(&p, 1, 10000) > 0)
> + if (read(s, buf, sizeof(buf)) > 0)
> + exit(0);
> +
> + exit(1);
> +}
> +
> +int daemonize(void)
> +{
> + int x;
> + int fd[2];
> +
> + if (socketpair(PF_LOCAL, SOCK_STREAM, 0, fd)) {
> + syslog(LOG_ERR, "socketpair : %s", strerror(errno));
> + exit(1);
> + }
>
> /* detach from terminal */
> switch (fork()) {
> @@ -161,13 +187,17 @@ void daemonize(void)
> close(0); close(1); close(2);
> setsid();
> x = open("/dev/null", O_RDWR); x = dup(x); x = dup(x);
> - break;
> + close(fd[0]);
> + return fd[1];
> case -1:
> syslog(LOG_ERR, "fork: %s", strerror(errno));
> - retval = 1;
> + exit(1);
> default:
> - exit(retval);
> + close(fd[1]);
> + wait_and_exit(fd[0]);
> }
> +
> + return 0;
> }
>
> static int file_test(const char *path)
> @@ -182,6 +212,7 @@ int main(int argc, char *argv[])
> fd_set readfds, writefds;
> int c, n, nfds, x11_fd;
> int do_daemonize = 1;
> + int parent_socket = 0;
> int x11_sync = 0;
> struct sigaction act;
>
> @@ -236,7 +267,7 @@ int main(int argc, char *argv[])
> }
>
> if (do_daemonize)
> - daemonize();
> + parent_socket = daemonize();
>
> reconnect:
> if (version_mismatch) {
> @@ -275,6 +306,13 @@ reconnect:
> vdagent_file_xfers = vdagent_file_xfers_create(client, fx_dir,
> fx_open_dir, debug);
>
> + if (parent_socket) {
> + if (write(parent_socket, "OK", 2) != 2)
> + syslog(LOG_WARNING, "Parent already gone.");
> + close(parent_socket);
> + parent_socket = 0;
> + }
> +
> while (client && !quit) {
> FD_ZERO(&readfds);
> FD_ZERO(&writefds);
>
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