Re: [Spice-devel] [PATCH (v2)] Make sure the child is able to connect to the X server before exiting the mainline.

2014-07-10 Thread Alon Levy 
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, 1)  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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[Spice-devel] [PATCH (v2)] Make sure the child is able to connect to the X server before exiting the mainline.

2014-07-09 Thread Jeremy White 
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
---
 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, 1)  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);
-- 
1.7.10.4

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