From c29743cdbdd8f5b526704705de7cc2ae3d0790c7 Mon Sep 17 00:00:00 2001

From: "Richard W.M. Jones" <rjones@redhat.com>

Date: Tue, 22 Mar 2016 14:04:26 +0000

Subject: [PATCH] launch: direct: Don't run qemu -version.

Dr. David Gilbert pointed out to me that the first line of the

qemu -help output includes the qemu version, so we don't need

to run qemu -version at all.

This saves about 0.04s on the launch time when using the direct

backend.

(cherry picked from commit b7b34119766349522528fdfe56237bede0794b6a)

---

 src/launch-direct.c | 54 +++++++++++++++++++----------------------------------

 1 file changed, 19 insertions(+), 35 deletions(-)

diff --git a/src/launch-direct.c b/src/launch-direct.c

index cbaf4f3..646f9c6 100644

--- a/src/launch-direct.c

+++ b/src/launch-direct.c

@@ -61,7 +61,6 @@ struct backend_direct_data {

   pid_t recoverypid;          /* Recovery process PID. */

   char *qemu_help;            /* Output of qemu -help. */

-  char *qemu_version;         /* Output of qemu -version. */

   char *qemu_devices;         /* Output of qemu -device ? */

   /* qemu version (0, 0 if unable to parse). */

@@ -935,22 +934,18 @@ print_qemu_command_line (guestfs_h *g, char **argv)

 static void parse_qemu_version (guestfs_h *g, struct backend_direct_data *data);

 static void read_all (guestfs_h *g, void *retv, const char *buf, size_t len);

-/* Test qemu binary (or wrapper) runs, and do 'qemu -help' and

- * 'qemu -version' so we know what options this qemu supports and

- * the version.

+/* Test qemu binary (or wrapper) runs, and do 'qemu -help' so we know

+ * the version of qemu what options this qemu supports.

  */

 static int

 test_qemu (guestfs_h *g, struct backend_direct_data *data)

 {

   CLEANUP_CMD_CLOSE struct command *cmd1 = guestfs_int_new_command (g);

   CLEANUP_CMD_CLOSE struct command *cmd2 = guestfs_int_new_command (g);

-  CLEANUP_CMD_CLOSE struct command *cmd3 = guestfs_int_new_command (g);

   int r;

   free (data->qemu_help);

   data->qemu_help = NULL;

-  free (data->qemu_version);

-  data->qemu_version = NULL;

   free (data->qemu_devices);

   data->qemu_devices = NULL;

@@ -964,34 +959,24 @@ test_qemu (guestfs_h *g, struct backend_direct_data *data)

   if (r == -1 || !WIFEXITED (r) || WEXITSTATUS (r) != 0)

     goto error;

+  parse_qemu_version (g, data);

+

   guestfs_int_cmd_add_arg (cmd2, g->hv);

   guestfs_int_cmd_add_arg (cmd2, "-display");

   guestfs_int_cmd_add_arg (cmd2, "none");

-  guestfs_int_cmd_add_arg (cmd2, "-version");

-  guestfs_int_cmd_set_stdout_callback (cmd2, read_all, &data->qemu_version,

-				       CMD_STDOUT_FLAG_WHOLE_BUFFER);

-  r = guestfs_int_cmd_run (cmd2);

-  if (r == -1 || !WIFEXITED (r) || WEXITSTATUS (r) != 0)

-    goto error;

-

-  parse_qemu_version (g, data);

-

-  guestfs_int_cmd_add_arg (cmd3, g->hv);

-  guestfs_int_cmd_add_arg (cmd3, "-display");

-  guestfs_int_cmd_add_arg (cmd3, "none");

-  guestfs_int_cmd_add_arg (cmd3, "-machine");

-  guestfs_int_cmd_add_arg (cmd3,

+  guestfs_int_cmd_add_arg (cmd2, "-machine");

+  guestfs_int_cmd_add_arg (cmd2,

 #ifdef MACHINE_TYPE

                            MACHINE_TYPE ","

 #endif

                            "accel=kvm:tcg");

-  guestfs_int_cmd_add_arg (cmd3, "-device");

-  guestfs_int_cmd_add_arg (cmd3, "?");

-  guestfs_int_cmd_clear_capture_errors (cmd3);

-  guestfs_int_cmd_set_stderr_to_stdout (cmd3);

-  guestfs_int_cmd_set_stdout_callback (cmd3, read_all, &data->qemu_devices,

+  guestfs_int_cmd_add_arg (cmd2, "-device");

+  guestfs_int_cmd_add_arg (cmd2, "?");

+  guestfs_int_cmd_clear_capture_errors (cmd2);

+  guestfs_int_cmd_set_stderr_to_stdout (cmd2);

+  guestfs_int_cmd_set_stdout_callback (cmd2, read_all, &data->qemu_devices,

 				       CMD_STDOUT_FLAG_WHOLE_BUFFER);

-  r = guestfs_int_cmd_run (cmd3);

+  r = guestfs_int_cmd_run (cmd2);

   if (r == -1 || !WIFEXITED (r) || WEXITSTATUS (r) != 0)

     goto error;

@@ -1005,8 +990,9 @@ test_qemu (guestfs_h *g, struct backend_direct_data *data)

   return -1;

 }

-/* Parse data->qemu_version (if not NULL) into the major and minor

- * version of qemu, but don't fail if parsing is not possible.

+/* Parse the first line of data->qemu_help (if not NULL) into the

+ * major and minor version of qemu, but don't fail if parsing is not

+ * possible.

  */

 static void

 parse_qemu_version (guestfs_h *g, struct backend_direct_data *data)

@@ -1017,13 +1003,13 @@ parse_qemu_version (guestfs_h *g, struct backend_direct_data *data)

   data->qemu_version_major = 0;

   data->qemu_version_minor = 0;

-  if (!data->qemu_version)

+  if (!data->qemu_help)

     return;

-  if (!match2 (g, data->qemu_version, re_major_minor, &major_s, &minor_s)) {

+  if (!match2 (g, data->qemu_help, re_major_minor, &major_s, &minor_s)) {

   parse_failed:

-    debug (g, "%s: failed to parse qemu version string '%s'",

-           __func__, data->qemu_version);

+    debug (g, "%s: failed to parse qemu version string from the first line of the output of '%s -help'.  When reporting this bug please include the -help output.",

+           __func__, g->hv);

     return;

   }

@@ -1505,8 +1491,6 @@ shutdown_direct (guestfs_h *g, void *datav, int check_for_errors)

   free (data->qemu_help);

   data->qemu_help = NULL;

-  free (data->qemu_version);

-  data->qemu_version = NULL;

   free (data->qemu_devices);

   data->qemu_devices = NULL;

-- 

2.7.4