[1/2] qmp/hmp: add writeconfig

Commit Message

Eduardo Otubo Feb. 15, 2017, 10:14 a.m. UTC

This patch adds support for the command `writeconfig' on the QMP and HMP
consoles. This is a simple way to keep track of current state of VM
after series of hotplugs and/or hotunplugs of different devices:

  (qemu) writeconfig qemu.conf

Signed-off-by: Eduardo Otubo <[e-mail]>
---
 hmp-commands.hx  | 14 ++++++++++++++
 hmp.c            |  9 +++++++++
 hmp.h            |  1 +
 qapi-schema.json | 20 ++++++++++++++++++++
 ui/console.c     | 14 ++++++++++++++
 5 files changed, 58 insertions(+)

Comments

Eric Blake Feb. 16, 2017, 4:12 p.m. UTC | #1

On 02/15/2017 04:14 AM, Eduardo Otubo wrote:
> This patch adds support for the command `writeconfig' on the QMP and HMP
> consoles. This is a simple way to keep track of current state of VM
> after series of hotplugs and/or hotunplugs of different devices:
> 
>   (qemu) writeconfig qemu.conf
> 
> Signed-off-by: Eduardo Otubo <[e-mail]>
> ---

> +++ b/qapi-schema.json
> @@ -4696,6 +4696,26 @@
>    'data': { 'keys': ['KeyValue'], '*hold-time': 'int' } }
>  
>  ##
> +# @writeconfig:
> +#
> +# Write config to file.
> +#
> +# @filename: the path of a new file to store the current config
> +#
> +# Returns: Nothing on success
> +#
> +# Since: 2.7.0
> +#

You've missed 2.7 by two releases.  This should be 2.9.


> +++ b/ui/console.c

>  
> +void qmp_writeconfig(const char *filename, Error **errp)
> +{
> +    if (filename == NULL) {
> +        error_setg(errp, "You must specify a filename.");
> +        return;
> +    }

Dead code; QAPI ensures that filename is non-NULL.
Even if it weren't dead code, error_setg() messages should not end in '.'.

> +
> +    FILE *fp;
> +    fp = fopen(filename, "w");

Please use qemu_fopen() - that way, the caller can also use qemu's magic
/dev/fdset to write to a pre-opened fd even when qemu itself can't
open() the file.

Patch

diff --git a/hmp-commands.hx b/hmp-commands.hx
index 88192817b2..ac562192bb 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -252,6 +252,20 @@  Password: ********
 ETEXI
 
     {
+        .name       = "writeconfig",
+        .args_type  = "filename:F",
+        .params     = "filename",
+        .help       = "write config file",
+        .cmd       = hmp_writeconfig,
+    },
+
+STEXI
+@item writeconfig @var{filename}
+@findex writeconfig
+Write config file @var{filename}.
+ETEXI
+
+    {
         .name       = "screendump",
         .args_type  = "filename:F",
         .params     = "filename",
diff --git a/hmp.c b/hmp.c
index 2bc4f062bb..4f2b8a10d2 100644
--- a/hmp.c
+++ b/hmp.c
@@ -1913,6 +1913,15 @@  err_out:
     goto out;
 }
 
+void hmp_writeconfig(Monitor *mon, const QDict *qdict)
+{
+    const char *filename = qdict_get_str(qdict, "filename");
+    Error *err = NULL;
+
+    qmp_writeconfig(filename, &err);
+    hmp_handle_error(mon, &err);
+}
+
 void hmp_screendump(Monitor *mon, const QDict *qdict)
 {
     const char *filename = qdict_get_str(qdict, "filename");
diff --git a/hmp.h b/hmp.h
index 05daf7cd5c..63d44fe50f 100644
--- a/hmp.h
+++ b/hmp.h
@@ -94,6 +94,7 @@  void hmp_getfd(Monitor *mon, const QDict *qdict);
 void hmp_closefd(Monitor *mon, const QDict *qdict);
 void hmp_sendkey(Monitor *mon, const QDict *qdict);
 void hmp_screendump(Monitor *mon, const QDict *qdict);
+void hmp_writeconfig(Monitor *mon, const QDict *qdict);
 void hmp_nbd_server_start(Monitor *mon, const QDict *qdict);
 void hmp_nbd_server_add(Monitor *mon, const QDict *qdict);
 void hmp_nbd_server_stop(Monitor *mon, const QDict *qdict);
diff --git a/qapi-schema.json b/qapi-schema.json
index 5edb08d621..c19b1ff3df 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -4696,6 +4696,26 @@ 
   'data': { 'keys': ['KeyValue'], '*hold-time': 'int' } }
 
 ##
+# @writeconfig:
+#
+# Write config to file.
+#
+# @filename: the path of a new file to store the current config
+#
+# Returns: Nothing on success
+#
+# Since: 2.7.0
+#
+# Example:
+#
+# -> { "execute": "writeconfig",
+#      "arguments": { "filename": "/tmp/qemu.conf" } }
+# <- { "return": {} }
+#
+##
+{ 'command': 'writeconfig', 'data': {'filename': 'str'} }
+
+##
 # @screendump:
 #
 # Write a PPM of the VGA screen to a file.
diff --git a/ui/console.c b/ui/console.c
index 49d0740b40..d2e3d753a8 100644
--- a/ui/console.c
+++ b/ui/console.c
@@ -30,6 +30,7 @@ 
 #include "sysemu/char.h"
 #include "trace.h"
 #include "exec/memory.h"
+#include "qemu/config-file.h"
 
 #define DEFAULT_BACKSCROLL 512
 #define CONSOLE_CURSOR_PERIOD 500
@@ -342,6 +343,19 @@  write_err:
     goto out;
 }
 
+void qmp_writeconfig(const char *filename, Error **errp)
+{
+    if (filename == NULL) {
+        error_setg(errp, "You must specify a filename.");
+        return;
+    }
+
+    FILE *fp;
+    fp = fopen(filename, "w");
+    qemu_config_write(fp);
+    fclose(fp);
+}
+
 void qmp_screendump(const char *filename, Error **errp)
 {
     QemuConsole *con = qemu_console_lookup_by_index(0);