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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v2] libxl: add "xl qemu-monitor-command"
Add a new xl command "qemu-monitor-command" to issue arbitrary commands
to a domain's device model. Syntax is:
xl qemu-monitor-command <domain> <command>
The command is issued via qmp human-monitor-command command. Any
information returned by the command is printed to stdout.
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
docs/man/xl.pod.1.in | 36 ++++++++++++++++++++++++++++++++++++
tools/libxl/libxl.h | 14 ++++++++++++++
tools/libxl/libxl_colo_qdisk.c | 2 +-
tools/libxl/libxl_internal.h | 3 ++-
tools/libxl/libxl_qmp.c | 38 ++++++++++++++++++++++++++++++++++++--
tools/libxl/xl.h | 1 +
tools/libxl/xl_cmdimpl.c | 27 +++++++++++++++++++++++++++
tools/libxl/xl_cmdtable.c | 5 +++++
8 files changed, 122 insertions(+), 4 deletions(-)
diff --git a/docs/man/xl.pod.1.in b/docs/man/xl.pod.1.in
index 1adf322..a2be541 100644
--- a/docs/man/xl.pod.1.in
+++ b/docs/man/xl.pod.1.in
@@ -1516,6 +1516,42 @@ List pass-through usb devices for a domain.
=back
+=head1 DEVICE-MODEL CONTROL
+
+=over 4
+
+=item B<qemu-monitor-command> I<domain-id> I<command>
+
+Issue a monitor command to the device model of the domain specified by
+I<domain-id>. I<command> can be any valid command qemu understands. This
+can be e.g. used to add non-standard devices or devices with non-standard
+parameters to a domain. The output of the command is printed to stdout.
+
+B<Warning:> This qemu monitor access is provided for convenience when
+debugging, troubleshooting, and experimenting. Its use is not
+supported by the Xen Project.
+
+Specifically, not all information printed by the qemu monitor will
+necessarily be accurate or complete, because in a Xen system qemu
+does not have a complete view of the guest.
+
+Furthermore, modifying the guest's setup via the qemu monitor may
+conflict with the Xen toolstack's assumptions. Resulting problems
+may include, but are not limited to: guest crashes; toolstack error
+messages; inability to migrate the guest; and security
+vulnerabilities which are not covered by the Xen Project security
+response policy.
+
+B<EXAMPLE>
+
+Obtain information of USB devices connected as such via the device model
+(only!) to a domain:
+
+ xl qemu-monitor-command vm1 'info usb'
+ Device 0.2, Port 5, Speed 480 Mb/s, Product Mass Storage
+
+=back
+
=head1 TMEM
=over 4
diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index e4c25c4..7cfa540 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -275,6 +275,12 @@
#define LIBXL_HAVE_BUILD_ID 1
/*
+ * LIBXL_HAVE_QEMU_MONITOR_COMMAND indiactes the availability of the
+ * libxl_qemu_monitor_command() function.
+ */
+#define LIBXL_HAVE_QEMU_MONITOR_COMMAND 1
+
+/*
* libxl ABI compatibility
*
* The only guarantee which libxl makes regarding ABI compatibility
@@ -2152,6 +2158,14 @@ void libxl_psr_cat_info_list_free(libxl_psr_cat_info
*list, int nr);
int libxl_fd_set_cloexec(libxl_ctx *ctx, int fd, int cloexec);
int libxl_fd_set_nonblock(libxl_ctx *ctx, int fd, int nonblock);
+/*
+ * Issue a qmp monitor command to the device model of the specified domain.
+ * The function returns the output of the command in a new allocated buffer
+ * via output.
+ */
+int libxl_qemu_monitor_command(libxl_ctx *ctx, uint32_t domid,
+ const char *command_line, char **output);
+
#include <libxl_event.h>
#endif /* LIBXL_H */
diff --git a/tools/libxl/libxl_colo_qdisk.c b/tools/libxl/libxl_colo_qdisk.c
index c23b81b..d271d1f 100644
--- a/tools/libxl/libxl_colo_qdisk.c
+++ b/tools/libxl/libxl_colo_qdisk.c
@@ -173,7 +173,7 @@ static void colo_qdisk_save_preresume(libxl__egc *egc,
"file.driver=nbd,file.host=%s,file.port=%d,"
"file.export=%s,node-name=%s,if=none",
host, port, export_name, node);
- ret = libxl__qmp_hmp(gc, domid, cmd);
+ ret = libxl__qmp_hmp(gc, domid, cmd, NULL);
if (ret)
rc = ERROR_FAIL;
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index ce8e17a..9f534c4 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -1818,7 +1818,8 @@ _hidden int libxl__qmp_x_blockdev_change(libxl__gc *gc,
int domid,
const char *parant,
const char *child, const char *node);
/* run a hmp command in qmp mode */
-_hidden int libxl__qmp_hmp(libxl__gc *gc, int domid, const char *command_line);
+_hidden int libxl__qmp_hmp(libxl__gc *gc, int domid, const char *command_line,
+ char **out);
/* close and free the QMP handler */
_hidden void libxl__qmp_close(libxl__qmp_handler *qmp);
/* remove the socket file, if the file has already been removed,
diff --git a/tools/libxl/libxl_qmp.c b/tools/libxl/libxl_qmp.c
index 63c49c5..33883b8 100644
--- a/tools/libxl/libxl_qmp.c
+++ b/tools/libxl/libxl_qmp.c
@@ -1103,14 +1103,48 @@ int libxl__qmp_x_blockdev_change(libxl__gc *gc, int
domid, const char *parent,
return qmp_run_command(gc, domid, "x-blockdev-change", args, NULL, NULL);
}
-int libxl__qmp_hmp(libxl__gc *gc, int domid, const char *command_line)
+static int hmp_callback(libxl__qmp_handler *qmp,
+ const libxl__json_object *response,
+ void *opaque)
+{
+ char **output = opaque;
+ GC_INIT(qmp->ctx);
+ int rc = 0;
+
+ if (!output)
+ goto out;
+
+ *output = NULL;
+
+ if (libxl__json_object_is_string(response)) {
+ *output = libxl__strdup(gc, libxl__json_object_get_string(response));
+ goto out;
+ }
+
+ LOG(ERROR, "Response has unexpected format");
+ rc = ERROR_FAIL;
+
+out:
+ return rc;
+}
+
+int libxl__qmp_hmp(libxl__gc *gc, int domid, const char *command_line,
+ char **output)
{
libxl__json_object *args = NULL;
qmp_parameters_add_string(gc, &args, "command-line", command_line);
return qmp_run_command(gc, domid, "human-monitor-command", args,
- NULL, NULL);
+ hmp_callback, output);
+}
+
+int libxl_qemu_monitor_command(libxl_ctx *ctx, uint32_t domid,
+ const char *command_line, char **output)
+{
+ GC_INIT(ctx);
+
+ return libxl__qmp_hmp(gc, domid, command_line, output);
}
int libxl__qmp_initializations(libxl__gc *gc, uint32_t domid,
diff --git a/tools/libxl/xl.h b/tools/libxl/xl.h
index e601ca1..0a8c813 100644
--- a/tools/libxl/xl.h
+++ b/tools/libxl/xl.h
@@ -133,6 +133,7 @@ int main_psr_cmt_show(int argc, char **argv);
int main_psr_cat_cbm_set(int argc, char **argv);
int main_psr_cat_show(int argc, char **argv);
#endif
+int main_qemu_monitor_command(int argc, char **argv);
void help(const char *command);
diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 7540fb1..ad2cba5 100644
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -9536,6 +9536,33 @@ int main_psr_hwinfo(int argc, char **argv)
#endif
+int main_qemu_monitor_command(int argc, char **argv)
+{
+ int opt;
+ uint32_t domid;
+ char *cmd;
+ char *output;
+ int ret;
+
+ SWITCH_FOREACH_OPT(opt, "", NULL, "qemu-monitor-command", 2) {
+ /* No options */
+ }
+
+ domid = find_domain(argv[optind]);
+ cmd = argv[optind + 1];
+
+ if (argc - optind > 2) {
+ fprintf(stderr, "Invalid arguments.\n");
+ return 1;
+ }
+
+ ret = libxl_qemu_monitor_command(ctx, domid, cmd, &output);
+ if (!ret && output)
+ printf("%s\n", output);
+
+ return ret;
+}
+
/*
* Local variables:
* mode: C
diff --git a/tools/libxl/xl_cmdtable.c b/tools/libxl/xl_cmdtable.c
index 85c1e0f..78786fe 100644
--- a/tools/libxl/xl_cmdtable.c
+++ b/tools/libxl/xl_cmdtable.c
@@ -584,6 +584,11 @@ struct cmd_spec cmd_table[] = {
"List information about all USB controllers and devices for a domain",
"<Domain>",
},
+ { "qemu-monitor-command",
+ &main_qemu_monitor_command, 0, 1,
+ "Issue a qemu monitor command to the device model of a domain",
+ "<Domain> <Command>",
+ },
};
int cmdtable_len = sizeof(cmd_table)/sizeof(struct cmd_spec);
--
2.6.6
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