# HG changeset patch
# User cl349@xxxxxxxxxxxxxxxxxxxx
# Node ID 6d4c0bfc3c1c15d1871d17698bfd78a9ea05aff5
# Parent f41f8d753b7a94a06ec77727ca1c0db557b49e1e
Wait a little bit for tty to appear.
There is a race condition that occurs after xend creates a domain.
The console client might be running before the console daemon has
noticed the new domain and setup a pty for it.
Signed-off-by: Anthony Liguori <aliguori@xxxxxxxxxx>
Signed-off-by: Christian Limpach <Christian.Limpach@xxxxxxxxxxxx>
diff -r f41f8d753b7a -r 6d4c0bfc3c1c tools/console/client/main.c
--- a/tools/console/client/main.c Wed Aug 31 09:32:52 2005
+++ b/tools/console/client/main.c Wed Aug 31 10:24:43 2005
@@ -176,6 +176,7 @@
unsigned int len = 0;
struct xs_handle *xs;
char *end;
+ time_t now;
while((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
switch(ch) {
@@ -215,13 +216,37 @@
snprintf(path, sizeof(path), "/console/%d/tty", domid);
str_pty = xs_read(xs, path, &len);
+
/* FIXME consoled currently does not assume domain-0 doesn't have a
console which is good when we break domain-0 up. To keep us
user friendly, we'll bail out here since no data will ever show
up on domain-0. */
- if (domid == 0 || str_pty == NULL) {
+ if (domid == 0) {
err(errno, "Could not read tty from store");
}
+
+ /* Wait a little bit for tty to appear. There is a race
+ condition that occurs after xend creates a domain. This
+ code might be running before consoled has noticed the new
+ domain and setup a pty for it.
+
+ A xenstore watch would slightly improve responsiveness but
+ a timeout would still be needed since we don't want to
+ block forever if given an invalid domain or worse yet, a
+ domain that someone else has connected to. */
+
+ now = time(0);
+ while (str_pty == NULL && (now + 5) > time(0)) {
+ struct timeval tv = { 0, 500 };
+ select(0, NULL, NULL, NULL, &tv); /* pause briefly */
+
+ str_pty = xs_read(xs, path, &len);
+ }
+
+ if (str_pty == NULL) {
+ err(errno, "Could not read tty from store");
+ }
+
spty = open(str_pty, O_RDWR | O_NOCTTY);
if (spty == -1) {
err(errno, "Could not open tty `%s'", str_pty);
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