2:05 p.m.
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.
---
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 e8450e1..25b0349 100644
--- a/src/launch-direct.c
+++ b/src/launch-direct.c
@@ -54,7 +54,6 @@ 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). */
@@ -931,22 +930,18 @@ 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;
@@ -960,34 +955,24 @@ 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;
@@ -1001,8 +986,9 @@ 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)
@@ -1013,13 +999,13 @@ 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;
}
@@ -1508,8 +1494,6 @@ 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