[RFC PATCH 5/8] libxl: libxl_{primary_, }console_exec now take notify_fd argument

[Wei Liu <wei.liu2@citrix.com>]

The new argument will be passed down to xenconsole process, which then
uses it to notify readiness.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 tools/libxl/libxl.c | 15 +++++++++++----
 tools/libxl/libxl.h | 43 ++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 51 insertions(+), 7 deletions(-)

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index a611b29..7f2f2b6 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -1777,13 +1777,14 @@ out:
 }
 
 int libxl_console_exec(libxl_ctx *ctx, uint32_t domid, int cons_num,
-                       libxl_console_type type)
+                       libxl_console_type type, int notify_fd)
 {
     GC_INIT(ctx);
     int rc;
     char *p = GCSPRINTF("%s/xenconsole", libxl__private_bindir_path());
     char *domid_s = GCSPRINTF("%d", domid);
     char *cons_num_s = GCSPRINTF("%d", cons_num);
+    char *notify_fd_s;
     char *cons_type_s;
     char *tty_path;
     const char *tty;
@@ -1822,7 +1823,13 @@ int libxl_console_exec(libxl_ctx *ctx, uint32_t domid, int cons_num,
         goto out;
     }
 
-    execl(p, p, domid_s, "--num", cons_num_s, "--type", cons_type_s, (void *)NULL);
+    if (notify_fd != -1) {
+        notify_fd_s = GCSPRINTF("%d", notify_fd);
+        execl(p, p, domid_s, "--num", cons_num_s, "--type", cons_type_s,
+              "--start-notify-fd", notify_fd_s, (void *)NULL);
+    } else
+        execl(p, p, domid_s, "--num", cons_num_s, "--type", cons_type_s,
+              (void *)NULL);
 
 out:
     GC_FREE;
@@ -1894,7 +1901,7 @@ out:
     return rc;
 }
 
-int libxl_primary_console_exec(libxl_ctx *ctx, uint32_t domid_vm)
+int libxl_primary_console_exec(libxl_ctx *ctx, uint32_t domid_vm, int notify_fd)
 {
     uint32_t domid;
     int cons_num;
@@ -1903,7 +1910,7 @@ int libxl_primary_console_exec(libxl_ctx *ctx, uint32_t domid_vm)
 
     rc = libxl__primary_console_find(ctx, domid_vm, &domid, &cons_num, &type);
     if ( rc ) return rc;
-    return libxl_console_exec(ctx, domid, cons_num, type);
+    return libxl_console_exec(ctx, domid, cons_num, type, notify_fd);
 }
 
 int libxl_primary_console_get_tty(libxl_ctx *ctx, uint32_t domid_vm,
diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index 48a43ce..f821e05 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -67,6 +67,14 @@
  * the same $(XEN_VERSION) (e.g. throughout a major release).
  */
 
+/* LIBXL_HAVE_CONSOLE_NOTIFY_FD
+ *
+ * If this is defined, libxl_console_exec and
+ * libxl_primary_console_exe take a notify_fd parameter. That
+ * parameter will be used to notify the caller that the console is connected.
+ */
+#define LIBXL_HAVE_CONSOLE_NOTIFY_FD 1
+
 /* LIBXL_HAVE_CONST_COPY_AND_LENGTH_FUNCTIONS
  *
  * If this is defined, the copy functions have constified src parameter and the
@@ -1413,15 +1421,44 @@ int libxl_wait_for_free_memory(libxl_ctx *ctx, uint32_t domid, uint32_t memory_k
 int libxl_wait_for_memory_target(libxl_ctx *ctx, uint32_t domid, int wait_secs);
 
 int libxl_vncviewer_exec(libxl_ctx *ctx, uint32_t domid, int autopass);
-int libxl_console_exec(libxl_ctx *ctx, uint32_t domid, int cons_num, libxl_console_type type);
+
+/*
+ * If notify_fd is not -1, xenconsole will write 0x00 to it to nofity
+ * the caller that it has connected to the guest console.
+ */
+int libxl_console_exec(libxl_ctx *ctx, uint32_t domid, int cons_num,
+                       libxl_console_type type, int notify_fd);
 /* libxl_primary_console_exec finds the domid and console number
  * corresponding to the primary console of the given vm, then calls
  * libxl_console_exec with the right arguments (domid might be different
  * if the guest is using stubdoms).
  * This function can be called after creating the device model, in
  * case of HVM guests, and before libxl_run_bootloader in case of PV
- * guests using pygrub. */
-int libxl_primary_console_exec(libxl_ctx *ctx, uint32_t domid_vm);
+ * guests using pygrub.
+ * If notify_fd is not -1, xenconsole will write 0x00 to it to nofity
+ * the caller that it has connected to the guest console.
+ */
+int libxl_primary_console_exec(libxl_ctx *ctx, uint32_t domid_vm,
+                               int notify_fd);
+
+#if defined(LIBXL_API_VERSION) && LIBXL_API_VERSION < 0x040800
+
+static inline int libxl_console_exec_0x040700(libxl_ctx *ctx,
+                                              uint32_t domid, int cons_num,
+                                              libxl_console_type type)
+{
+    return libxl_console_exec(ctx, domid, cons_num, type, -1);
+}
+#define libxl_console_exec libxl_console_exec_0x040700
+
+static inline libxl_primary_console_exec_0x040700(libxl_ctx *ctx,
+                                                  uint32_t domid_vm)
+{
+    return libxl_primary_console_exec(ctx, domid_vm, -1);
+}
+#define libxl_primary_console_exec libxl_primary_console_exec_0x040700
+
+#endif
 
 /* libxl_console_get_tty retrieves the specified domain's console tty path
  * and stores it in path. Caller is responsible for freeing the memory.
-- 
2.1.4


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