>
> On Tue, Oct 17, 2017 at 10:09 AM, Frediano Ziglio <fziglio@xxxxxxxxxx> wrote:
> > From: Jakub Janků <janku.jakub.jj@xxxxxxxxx>
> >
> > Replace existing main while-loop with GMainLoop.
> >
> > Use GIOChannel with g_io_add_watch() to manage IO
> > from x11 connections in the main loop.
> >
> > udscs_connect() now internally creates GSources
> > by calling g_io_add_watch().
> > This enables GMainLoop integration,
> > clients no longer need to call
> > udscs_client_fill_fds() and
> > udscs_client_handle_fds() in a loop.
> > Read callback and udscs_write() functions as before.
> >
> > Signals are also handled in the main loop,
> > using g_unix_signal_add().
> > SIGQUIT is currently not supported by GLib.
> >
> > This enables further GTK+ integration in the future.
> >
> > Signed-off-by: Victor Toso <victortoso@xxxxxxxxxx>
> > ---
> > src/udscs.c | 60 +++++++++++++++++++
> > src/vdagent/vdagent.c | 159
> > +++++++++++++++++++++++++++-----------------------
> > 2 files changed, 145 insertions(+), 74 deletions(-)
> >
> > Changes since v4:
> > - remove source ids and use g_source_remove_by_user_data to remove
> > all sources, even signal ones;
> > - register first connection event with g_timeout_add instead
> > of calling the callback directly.
> >
> > diff --git a/src/udscs.c b/src/udscs.c
> > index 8b16f89..3a1ea44 100644
> > --- a/src/udscs.c
> > +++ b/src/udscs.c
> > @@ -31,6 +31,8 @@
> > #include <errno.h>
> > #include <sys/socket.h>
> > #include <sys/un.h>
> > +#include <glib.h>
> > +#include <glib-unix.h>
> > #include "udscs.h"
> >
> > struct udscs_buf {
> > @@ -66,8 +68,16 @@ struct udscs_connection {
> >
> > struct udscs_connection *next;
> > struct udscs_connection *prev;
> > +
> > + GIOChannel *io_channel;
> > + guint write_watch_id;
> > + guint read_watch_id;
> > };
> >
> > +static gboolean udscs_io_channel_cb(GIOChannel *source,
> > + GIOCondition condition,
> > + gpointer data);
> > +
> > struct udscs_connection *udscs_connect(const char *socketname,
> > udscs_read_callback read_callback,
> > udscs_disconnect_callback disconnect_callback,
> > @@ -103,6 +113,17 @@ struct udscs_connection *udscs_connect(const char
> > *socketname,
> > return NULL;
> > }
> >
> > + conn->io_channel = g_io_channel_unix_new(conn->fd);
> > + if (!conn->io_channel) {
> > + udscs_destroy_connection(&conn);
> > + return NULL;
> > + }
> > + conn->read_watch_id =
> > + g_io_add_watch(conn->io_channel,
> > + G_IO_IN | G_IO_ERR | G_IO_NVAL,
> > + udscs_io_channel_cb,
> > + conn);
> > +
> > conn->read_callback = read_callback;
> > conn->disconnect_callback = disconnect_callback;
> >
> > @@ -141,6 +162,12 @@ void udscs_destroy_connection(struct udscs_connection
> > **connp)
> >
> > close(conn->fd);
> >
> > + if (conn->write_watch_id != 0)
> > + g_source_remove(conn->write_watch_id);
> > + if (conn->read_watch_id != 0)
> > + g_source_remove(conn->read_watch_id);
> > + g_clear_pointer(&conn->io_channel, g_io_channel_unref);
> > +
> > if (conn->debug)
> > syslog(LOG_DEBUG, "%p disconnected", conn);
> >
> > @@ -198,6 +225,13 @@ int udscs_write(struct udscs_connection *conn,
> > uint32_t type, uint32_t arg1,
> > conn, type, arg1, arg2, size);
> > }
> >
> > + if (conn->io_channel && conn->write_watch_id == 0)
> > + conn->write_watch_id =
> > + g_io_add_watch(conn->io_channel,
> > + G_IO_OUT | G_IO_ERR | G_IO_NVAL,
> > + udscs_io_channel_cb,
> > + conn);
> > +
> > if (!conn->write_buf) {
> > conn->write_buf = new_wbuf;
> > return 0;
> > @@ -353,6 +387,32 @@ int udscs_client_fill_fds(struct udscs_connection
> > *conn, fd_set *readfds,
> > return conn->fd + 1;
> > }
> >
> > +static gboolean udscs_io_channel_cb(GIOChannel *source,
> > + GIOCondition condition,
> > + gpointer data)
> > +{
> > + struct udscs_connection *conn = data;
> > +
> > + if (condition & G_IO_IN) {
> > + udscs_do_read(&conn);
> > + if (conn == NULL)
> > + return G_SOURCE_REMOVE;
> > + return G_SOURCE_CONTINUE;
> > + }
> > + if (condition & G_IO_OUT) {
> > + udscs_do_write(&conn);
> > + if (conn == NULL)
> > + return G_SOURCE_REMOVE;
> > + if (conn->write_buf)
> > + return G_SOURCE_CONTINUE;
> > + conn->write_watch_id = 0;
> > + return G_SOURCE_REMOVE;
> > + }
> > +
> > + udscs_destroy_connection(&conn);
> > + return G_SOURCE_REMOVE;
> > +}
> > +
> >
> > #ifndef UDSCS_NO_SERVER
> >
> > diff --git a/src/vdagent/vdagent.c b/src/vdagent/vdagent.c
> > index 69d8786..ac90634 100644
> > --- a/src/vdagent/vdagent.c
> > +++ b/src/vdagent/vdagent.c
> > @@ -34,8 +34,8 @@
> > #include <sys/select.h>
> > #include <sys/stat.h>
> > #include <spice/vd_agent.h>
> > -#include <glib.h>
> > #include <poll.h>
> > +#include <glib-unix.h>
> >
> > #include "udscs.h"
> > #include "vdagentd-proto.h"
> > @@ -48,6 +48,9 @@ typedef struct VDAgent {
> > struct vdagent_x11 *x11;
> > struct vdagent_file_xfers *xfers;
> > struct udscs_connection *conn;
> > + GIOChannel *x11_channel;
> > +
> > + GMainLoop *loop;
> > } VDAgent;
> >
> > static int quit = 0;
> > @@ -177,7 +180,7 @@ static void daemon_read_complete(struct
> > udscs_connection **connp,
> > if (strcmp((char *)data, VERSION) != 0) {
> > syslog(LOG_INFO, "vdagentd version mismatch: got %s expected
> > %s",
> > data, VERSION);
> > - udscs_destroy_connection(connp);
> > + g_main_loop_quit(agent->loop);
> > version_mismatch = 1;
> > }
> > break;
> > @@ -235,25 +238,12 @@ static void daemon_read_complete(struct
> > udscs_connection **connp,
> > }
> > }
> >
> > -static struct udscs_connection *client_setup_sync(void)
> > -{
> > - struct udscs_connection *conn = NULL;
> > -
> > - while (!quit) {
> > - conn = udscs_connect(vdagentd_socket, daemon_read_complete, NULL,
> > - vdagentd_messages, VDAGENTD_NO_MESSAGES,
> > - debug);
> > - if (conn || !do_daemonize || quit) {
> > - break;
> > - }
> > - sleep(1);
> > - }
> > - return conn;
> > -}
> > -
> > -static void quit_handler(int sig)
> > +static void daemon_disconnect_cb(struct udscs_connection *conn)
> > {
> > - quit = 1;
> > + VDAgent *agent = udscs_get_user_data(conn);
> > + agent->conn = NULL;
> > + if (agent->loop)
> > + g_main_loop_quit(agent->loop);
> > }
> >
> > /* When we daemonize, it is useful to have the main process
> > @@ -311,10 +301,34 @@ static int file_test(const char *path)
> > return stat(path, &buffer);
> > }
> >
> > +static gboolean x11_io_channel_cb(GIOChannel *source,
> > + GIOCondition condition,
> > + gpointer data)
> > +{
> > + VDAgent *agent = data;
> > + vdagent_x11_do_read(agent->x11);
> > +
> > + return G_SOURCE_CONTINUE;
> > +}
> > +
> > +gboolean vdagent_signal_handler(gpointer user_data)
> > +{
> > + VDAgent *agent = user_data;
> > + quit = TRUE;
> > + g_main_loop_quit(agent->loop);
> > + return G_SOURCE_REMOVE;
> > +}
> > +
> > static VDAgent *vdagent_new(void)
> > {
> > VDAgent *agent = g_new0(VDAgent, 1);
> >
> > + agent->loop = g_main_loop_new(NULL, FALSE);
> > +
> > + g_unix_signal_add(SIGINT, vdagent_signal_handler, agent);
> > + g_unix_signal_add(SIGHUP, vdagent_signal_handler, agent);
> > + g_unix_signal_add(SIGTERM, vdagent_signal_handler, agent);
> > +
> > return agent;
> > }
> >
> > @@ -324,14 +338,59 @@ static void vdagent_destroy(VDAgent *agent)
> > vdagent_x11_destroy(agent->x11, agent->conn == NULL);
> > udscs_destroy_connection(&agent->conn);
> >
> > + while (g_source_remove_by_user_data(agent))
> > + continue;
> > +
> > + g_clear_pointer(&agent->x11_channel, g_io_channel_unref);
> > + g_clear_pointer(&agent->loop, g_main_loop_unref);
> > g_free(agent);
> > }
> >
> > +static gboolean vdagent_init_async_cb(gpointer user_data)
> > +{
> > + VDAgent *agent = user_data;
> > +
> > + agent->conn = udscs_connect(vdagentd_socket,
> > + daemon_read_complete,
> > daemon_disconnect_cb,
> > + vdagentd_messages, VDAGENTD_NO_MESSAGES,
> > debug);
> > + if (agent->conn == NULL) {
> > + g_timeout_add_seconds(1, vdagent_init_async_cb, agent);
> > + return G_SOURCE_REMOVE;
> > + }
> > + udscs_set_user_data(agent->conn, agent);
> > +
> > + agent->x11 = vdagent_x11_create(agent->conn, debug, x11_sync);
> > + if (agent->x11 == NULL)
> > + goto err_init;
> > + agent->x11_channel =
> > g_io_channel_unix_new(vdagent_x11_get_fd(agent->x11));
> > + if (agent->x11_channel == NULL)
> > + goto err_init;
> > +
> > + g_io_add_watch(agent->x11_channel,
> > + G_IO_IN,
> > + x11_io_channel_cb,
> > + agent);
> > +
> > + if (!vdagent_init_file_xfer(agent))
> > + syslog(LOG_WARNING, "File transfer is disabled");
> > +
> > + if (parent_socket != -1) {
> > + if (write(parent_socket, "OK", 2) != 2)
> > + syslog(LOG_WARNING, "Parent already gone.");
> > + close(parent_socket);
> > + parent_socket = -1;
> > + }
> > +
> > + return G_SOURCE_REMOVE;
> > +
> > +err_init:
> > + g_main_loop_quit(agent->loop);
> > + quit = TRUE;
> > + return G_SOURCE_REMOVE;
> > +}
> > +
> > int main(int argc, char *argv[])
> > {
> > - fd_set readfds, writefds;
> > - int n, nfds, x11_fd;
> > - struct sigaction act;
> > GOptionContext *context;
> > GError *error = NULL;
> > VDAgent *agent;
> > @@ -357,14 +416,6 @@ int main(int argc, char *argv[])
> > if (vdagentd_socket == NULL)
> > vdagentd_socket = g_strdup(VDAGENTD_SOCKET);
> >
> > - memset(&act, 0, sizeof(act));
> > - act.sa_flags = SA_RESTART;
> > - act.sa_handler = quit_handler;
> > - sigaction(SIGINT, &act, NULL);
> > - sigaction(SIGHUP, &act, NULL);
> > - sigaction(SIGTERM, &act, NULL);
> > - sigaction(SIGQUIT, &act, NULL);
> > -
> > openlog("spice-vdagent", do_daemonize ? LOG_PID : (LOG_PID |
> > LOG_PERROR),
> > LOG_USER);
> >
> > @@ -385,53 +436,13 @@ reconnect:
> >
> > agent = vdagent_new();
> >
> > - agent->conn = client_setup_sync();
> > - if (agent->conn == NULL) {
> > - return 1;
> > - }
> > - udscs_set_user_data(agent->conn, agent);
> > + g_timeout_add(0, vdagent_init_async_cb, agent);
> >
> > - agent->x11 = vdagent_x11_create(agent->conn, debug, x11_sync);
> > - if (!agent->x11) {
> > - udscs_destroy_connection(&agent->conn);
> > - return 1;
> > - }
> > -
> > - if (!vdagent_init_file_xfer(agent))
> > - syslog(LOG_WARNING, "File transfer is disabled");
> > -
> > - if (parent_socket != -1) {
> > - if (write(parent_socket, "OK", 2) != 2)
> > - syslog(LOG_WARNING, "Parent already gone.");
> > - close(parent_socket);
> > - parent_socket = -1;
> > - }
> > -
> > - while (agent->conn && !quit) {
> > - FD_ZERO(&readfds);
> > - FD_ZERO(&writefds);
> > -
> > - nfds = udscs_client_fill_fds(agent->conn, &readfds, &writefds);
> > - x11_fd = vdagent_x11_get_fd(agent->x11);
> > - FD_SET(x11_fd, &readfds);
> > - if (x11_fd >= nfds)
> > - nfds = x11_fd + 1;
> > -
> > - n = select(nfds, &readfds, &writefds, NULL, NULL);
> > - if (n == -1) {
> > - if (errno == EINTR)
> > - continue;
> > - syslog(LOG_ERR, "Fatal error select: %s", strerror(errno));
> > - break;
> > - }
> > -
> > - if (FD_ISSET(x11_fd, &readfds))
> > - vdagent_x11_do_read(agent->x11);
> > - udscs_client_handle_fds(&agent->conn, &readfds, &writefds);
> > - }
> > + g_main_loop_run(agent->loop);
> >
> > vdagent_destroy(agent);
> > agent = NULL;
> > +
> > if (!quit && do_daemonize)
> > goto reconnect;
> >
> > --
> > 2.13.6
> >
>
> Just one more note on this:
> According to GTK docs for g_timeout_add_seconds():
> "Note that the first call of the timer may not be precise for timeouts
> of one second.
> If you need finer precision and have such a timeout,
> you may want to use g_timeout_add() instead."
> (this is basically the same what Christophe pointed out)
>
Yes, first iteration uses (last patch version) g_timeout_add.
> Since we remove the source in vdagent_init_async_cb() each time,
> the interval between each call might not be regular.
>
>From g_timeout_add_seconds_full documentation:
"Note that timeout functions may be delayed, due to the processing of other
event sources. Thus they should not be relied on for precise timing. After
each call to the timeout function, the time of the next timeout is recalculated
based on the current time and the given interval"
so creating the source every time does not change much on the timing.
> One solution would be to use g_timeout_add().
>
> Another solution:
> - in main():
> replace g_timeout_add(0, vdagent_init_async_cb, agent);
> with g_idle_add(vdagent_init_async_cb, agent);
>
> - in vdagent_init_async_cb():
> if (agent->conn == NULL) {
> if (g_idle_remove_by_data(agent)) {
> g_timeout_add_seconds(1, vdagent_init_async_cb, agent);
> return G_SOURCE_REMOVE;
> }
> return G_SOURCE_CONTINUE;
> }
> This way, the source doesn't have to be recreated every single time.
>
> Jakub
>
1 seconds is quite "human" timing thing, I don't think we need big
precision. If we really need precision I would use g_file_monitor_directory
where available to avoid entirely all the polling (which would be limited
to Unix systems without inotify or other GLib compatible implementations).
This way you can detect more or less precisely when the unix socket is
created/modified in the directory without having to check every second.
The g_idle solution should work and avoid creating the source every time,
only drawback is that adding another g_idle in a possible future is
tricky and prone to bugs as potentially the g_idle_remove_by_data would
remove the wrong source.
Frediano
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