libxl, xl: fix bootloader immediate console attach

Fix bugs related to console handling:

 * In libxl_primary_console_exec, if libxl__domain_type fails, do
   not abort, but instead log and return an error.  This can occur
   if the domid is invalid.

 * In xl's autoconnect_console, rename the ctx formal parameter so
   that when postfork creates a new ctx and puts it in the global ctx,
   we don't end up using the old one (via the formal parameter which
   has shadowed the global).

 * In xl's autoconnect_console, pass the domid from the event
   to libxl_primary_console_exec, rather than using the global domid
   (which has not yet been set, since it is only set at completion
   of the ao).

This causes xl create -c to once more work with pygrub.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 38c572674a..a3201dd0b7 100644
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -1496,9 +1496,11 @@ static int freemem(libxl_domain_build_info *b_info)
     return ERROR_NOMEM;
 }
 
-static void autoconnect_console(libxl_ctx *ctx, libxl_event *ev, void *priv)
+static void autoconnect_console(libxl_ctx *ctx_ignored,
+                                libxl_event *ev, void *priv)
 {
     pid_t *pid = priv;
+    uint32_t bldomid = ev->domid;
 
     libxl_event_free(ctx, ev);
 
@@ -1512,7 +1514,7 @@ static void autoconnect_console(libxl_ctx *ctx, libxl_event *ev, void *priv)
     postfork();
 
     sleep(1);
-    libxl_primary_console_exec(ctx, domid);
+    libxl_primary_console_exec(ctx, bldomid);
     /* Do not return. xl continued in child process */
     fprintf(stderr, "Unable to attach console\n");
     _exit(1);