[Xen-devel] [PATCH V3] libxl: Set path to console on domain startup.

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

The path to the pty of a Xen PV console is set only in
virDomainOpenConsole. But this is done too late. A call to
virDomainGetXMLDesc done before OpenConsole will not have the path to
the pty, but a call after OpenConsole will.

e.g. of the current issue.
Starting a domain with '<console type="pty"/>'
Then:
virDomainGetXMLDesc():
  <devices>
    <console type='pty'>
      <target type='xen' port='0'/>
    </console>
  </devices>
virDomainOpenConsole()
virDomainGetXMLDesc():
  <devices>
    <console type='pty' tty='/dev/pts/30'>
      <source path='/dev/pts/30'/>
      <target type='xen' port='0'/>
    </console>
  </devices>

The patch intend to have the TTY path on the first call of GetXMLDesc.
This is done by setting up the path at domain start up instead of in
OpenConsole.

https://bugzilla.redhat.com/show_bug.cgi?id=1170743

Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>

---
Change in V3:
  Using aop_console_how from libxl_domain_create_new()
  Ignore empty string that can return libxl_console_get_tty()

Change in V2:
  Adding bug report link.
  Reword the last part of the patch description.
  Cleanup the code.
  Use VIR_FREE before VIR_STRDUP.
  Remove the code from OpenConsole as it is now a duplicate.

CC: Jim Fehlig <jfehlig@xxxxxxxx>
CC: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
CC: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
---
 src/libxl/libxl_domain.c | 47 ++++++++++++++++++++++++++++++++++++++++++++---
 src/libxl/libxl_driver.c | 15 ---------------
 2 files changed, 44 insertions(+), 18 deletions(-)

diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c
index 9185117..804f9b9 100644
--- a/src/libxl/libxl_domain.c
+++ b/src/libxl/libxl_domain.c
@@ -1149,6 +1149,42 @@ libxlDomainFreeMem(libxlDomainObjPrivatePtr priv, 
libxl_domain_config *d_config)
     return ret;
 }
 
+static void
+libxlConsoleCallback(libxl_ctx *ctx, libxl_event* ev, void *for_callback)
+{
+    virDomainObjPtr vm = for_callback;
+    libxlDomainObjPrivatePtr priv = vm->privateData;
+    int i;
+
+    virObjectLock(vm);
+    for (i = 0; i < vm->def->nconsoles; i++) {
+        virDomainChrDefPtr chr = vm->def->consoles[i];
+        if (chr && chr->source.type == VIR_DOMAIN_CHR_TYPE_PTY) {
+            libxl_console_type console_type;
+            char *console = NULL;
+            int ret;
+
+            console_type =
+                (chr->targetType == VIR_DOMAIN_CHR_CONSOLE_TARGET_TYPE_SERIAL ?
+                 LIBXL_CONSOLE_TYPE_SERIAL : LIBXL_CONSOLE_TYPE_PV);
+            ret = libxl_console_get_tty(priv->ctx, ev->domid,
+                                        chr->target.port, console_type,
+                                        &console);
+            if (!ret) {
+                VIR_FREE(chr->source.data.file.path);
+                if (console && console[0] != '\0') {
+                    ignore_value(VIR_STRDUP(chr->source.data.file.path,
+                                            console));
+                }
+            }
+            VIR_FREE(console);
+        }
+    }
+    virObjectUnlock(vm);
+    libxl_event_free(ctx, ev);
+}
+
+
 /*
  * Start a domain through libxenlight.
  *
@@ -1173,6 +1209,7 @@ libxlDomainStart(libxlDriverPrivatePtr driver, 
virDomainObjPtr vm,
     libxl_domain_restore_params params;
 #endif
     virHostdevManagerPtr hostdev_mgr = driver->hostdevMgr;
+    libxl_asyncprogress_how aop_console_how;
 
     libxl_domain_config_init(&d_config);
 
@@ -1242,17 +1279,21 @@ libxlDomainStart(libxlDriverPrivatePtr driver, 
virDomainObjPtr vm,
 
     /* Unlock virDomainObj while creating the domain */
     virObjectUnlock(vm);
+
+    aop_console_how.for_callback = vm;
+    aop_console_how.callback = libxlConsoleCallback;
     if (restore_fd < 0) {
         ret = libxl_domain_create_new(priv->ctx, &d_config,
-                                      &domid, NULL, NULL);
+                                      &domid, NULL, &aop_console_how);
     } else {
 #ifdef LIBXL_HAVE_DOMAIN_CREATE_RESTORE_PARAMS
         params.checkpointed_stream = 0;
         ret = libxl_domain_create_restore(priv->ctx, &d_config, &domid,
-                                          restore_fd, &params, NULL, NULL);
+                                          restore_fd, &params, NULL,
+                                          &aop_console_how);
 #else
         ret = libxl_domain_create_restore(priv->ctx, &d_config, &domid,
-                                          restore_fd, NULL, NULL);
+                                          restore_fd, NULL, &aop_console_how);
 #endif
     }
     virObjectLock(vm);
diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c
index cad5101..fc0949d 100644
--- a/src/libxl/libxl_driver.c
+++ b/src/libxl/libxl_driver.c
@@ -3982,10 +3982,8 @@ libxlDomainOpenConsole(virDomainPtr dom,
 {
     virDomainObjPtr vm = NULL;
     int ret = -1;
-    libxl_console_type console_type;
     virDomainChrDefPtr chr = NULL;
     libxlDomainObjPrivatePtr priv;
-    char *console = NULL;
 
     virCheckFlags(VIR_DOMAIN_CONSOLE_FORCE, -1);
 
@@ -4027,18 +4025,6 @@ libxlDomainOpenConsole(virDomainPtr dom,
         goto cleanup;
     }
 
-    console_type =
-        (chr->targetType == VIR_DOMAIN_CHR_CONSOLE_TARGET_TYPE_SERIAL ?
-                            LIBXL_CONSOLE_TYPE_SERIAL : LIBXL_CONSOLE_TYPE_PV);
-
-    ret = libxl_console_get_tty(priv->ctx, vm->def->id, chr->target.port,
-                                console_type, &console);
-    if (ret)
-        goto cleanup;
-
-    if (VIR_STRDUP(chr->source.data.file.path, console) < 0)
-        goto cleanup;
-
     /* handle mutually exclusive access to console devices */
     ret = virChrdevOpen(priv->devs,
                         &chr->source,
@@ -4052,7 +4038,6 @@ libxlDomainOpenConsole(virDomainPtr dom,
     }
 
  cleanup:
-    VIR_FREE(console);
     if (vm)
         virObjectUnlock(vm);
     return ret;
-- 
Anthony PERARD


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