[Qemu-devel] [PATCH for 2.6 1/1] qemu-char: append opt to stop truncation of serial file

[Qemu-devel] [PATCH for 2.6 1/1] qemu-char: append opt to stop truncation of serial file

[Denis V. Lunev]

From: Olga Krishtal <okrishtal@parallels.com>

Our QA teams wants to preserve serial output of the guest in between QEMU
runs to perform post-analysis.

By default this behavior is off (file is truncated each time QEMU is started
or device is plugged).

Signed-off-by: Olga Krishtal <okrishtal@parallels.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Eric Blake <eblake@redhat.com>
CC: Markus Armbruster <armbru@redhat.com>
CC: Paolo Bonzini <pbonzini@redhat.com>
---
 qapi-schema.json |  7 ++++++-
 qemu-char.c      | 12 +++++++++++-
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/qapi-schema.json b/qapi-schema.json
index 8b1a423..802c138 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -3020,11 +3020,16 @@
 #
 # @in:  #optional The name of the input file
 # @out: The name of the output file
+# @append: #optional Open the file in append mode to preserve the content in
+#          between QEMU runs.
+#
+#          Since: 2.6
 #
 # Since: 1.4
 ##
 { 'struct': 'ChardevFile', 'data': { '*in' : 'str',
-                                   'out' : 'str' } }
+                                   'out' : 'str',
+                                   '*append': 'bool' } }
 
 ##
 # @ChardevHostdev:
diff --git a/qemu-char.c b/qemu-char.c
index 5448b0f..58454e2 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -3479,6 +3479,7 @@ static void qemu_chr_parse_file_out(QemuOpts *opts, ChardevBackend *backend,
     }
     backend->u.file = g_new0(ChardevFile, 1);
     backend->u.file->out = g_strdup(path);
+    backend->u.file->append = qemu_opt_get_bool(opts, "append", false);
 }
 
 static void qemu_chr_parse_stdio(QemuOpts *opts, ChardevBackend *backend,
@@ -4036,6 +4037,9 @@ QemuOptsList qemu_chardev_opts = {
         },{
             .name = "chardev",
             .type = QEMU_OPT_STRING,
+        },{
+            .name = "append",
+            .type = QEMU_OPT_BOOL,
         },
         { /* end of list */ }
     },
@@ -4096,7 +4100,13 @@ static CharDriverState *qmp_chardev_open_file(const char *id,
     ChardevFile *file = backend->u.file;
     int flags, in = -1, out;
 
-    flags = O_WRONLY | O_TRUNC | O_CREAT | O_BINARY;
+    flags = O_WRONLY | O_CREAT | O_BINARY;
+    if (file->append) {
+        flags |= O_APPEND;
+    } else {
+        flags |= O_TRUNC;
+    }
+
     out = qmp_chardev_open_file_source(file->out, flags, errp);
     if (out < 0) {
         return NULL;
-- 
2.1.4

Re: [Qemu-devel] [PATCH for 2.6 1/1] qemu-char: append opt to stop truncation of serial file

[Denis V. Lunev]

On 12/03/2015 09:24 AM, Denis V. Lunev wrote:
> From: Olga Krishtal <okrishtal@parallels.com>
>
> Our QA teams wants to preserve serial output of the guest in between QEMU
> runs to perform post-analysis.
>
> By default this behavior is off (file is truncated each time QEMU is started
> or device is plugged).
>
> Signed-off-by: Olga Krishtal <okrishtal@parallels.com>
> Signed-off-by: Denis V. Lunev <den@openvz.org>
> CC: Eric Blake <eblake@redhat.com>
> CC: Markus Armbruster <armbru@redhat.com>
> CC: Paolo Bonzini <pbonzini@redhat.com>
> ---
>   qapi-schema.json |  7 ++++++-
>   qemu-char.c      | 12 +++++++++++-
>   2 files changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 8b1a423..802c138 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -3020,11 +3020,16 @@
>   #
>   # @in:  #optional The name of the input file
>   # @out: The name of the output file
> +# @append: #optional Open the file in append mode to preserve the content in
> +#          between QEMU runs.
> +#
> +#          Since: 2.6
>   #
>   # Since: 1.4
>   ##
>   { 'struct': 'ChardevFile', 'data': { '*in' : 'str',
> -                                   'out' : 'str' } }
> +                                   'out' : 'str',
> +                                   '*append': 'bool' } }
>   
>   ##
>   # @ChardevHostdev:
> diff --git a/qemu-char.c b/qemu-char.c
> index 5448b0f..58454e2 100644
> --- a/qemu-char.c
> +++ b/qemu-char.c
> @@ -3479,6 +3479,7 @@ static void qemu_chr_parse_file_out(QemuOpts *opts, ChardevBackend *backend,
>       }
>       backend->u.file = g_new0(ChardevFile, 1);
>       backend->u.file->out = g_strdup(path);
> +    backend->u.file->append = qemu_opt_get_bool(opts, "append", false);
>   }
>   
>   static void qemu_chr_parse_stdio(QemuOpts *opts, ChardevBackend *backend,
> @@ -4036,6 +4037,9 @@ QemuOptsList qemu_chardev_opts = {
>           },{
>               .name = "chardev",
>               .type = QEMU_OPT_STRING,
> +        },{
> +            .name = "append",
> +            .type = QEMU_OPT_BOOL,
>           },
>           { /* end of list */ }
>       },
> @@ -4096,7 +4100,13 @@ static CharDriverState *qmp_chardev_open_file(const char *id,
>       ChardevFile *file = backend->u.file;
>       int flags, in = -1, out;
>   
> -    flags = O_WRONLY | O_TRUNC | O_CREAT | O_BINARY;
> +    flags = O_WRONLY | O_CREAT | O_BINARY;
> +    if (file->append) {
> +        flags |= O_APPEND;
> +    } else {
> +        flags |= O_TRUNC;
> +    }
> +
>       out = qmp_chardev_open_file_source(file->out, flags, errp);
>       if (out < 0) {
>           return NULL;
pls disregard. Originator e-mails are wrong. Sorry :(

Re: [Qemu-devel] [PATCH for 2.6 1/1] qemu-char: append opt to stop truncation of serial file

[Eric Blake]

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On 12/02/2015 11:24 PM, Denis V. Lunev wrote:
> From: Olga Krishtal <okrishtal@parallels.com>
> 
> Our QA teams wants to preserve serial output of the guest in between QEMU
> runs to perform post-analysis.
> 
> By default this behavior is off (file is truncated each time QEMU is started
> or device is plugged).
> 
> Signed-off-by: Olga Krishtal <okrishtal@parallels.com>
> Signed-off-by: Denis V. Lunev <den@openvz.org>
> CC: Eric Blake <eblake@redhat.com>
> CC: Markus Armbruster <armbru@redhat.com>
> CC: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  qapi-schema.json |  7 ++++++-
>  qemu-char.c      | 12 +++++++++++-
>  2 files changed, 17 insertions(+), 2 deletions(-)
> 
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 8b1a423..802c138 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -3020,11 +3020,16 @@
>  #
>  # @in:  #optional The name of the input file
>  # @out: The name of the output file
> +# @append: #optional Open the file in append mode to preserve the content in
> +#          between QEMU runs.
> +#
> +#          Since: 2.6

The 'Since' tag is wrong.  Also, the wording might sound better as:

# @append: #optional Open the file in append mode (default false to
           truncate) (Since 2.6)

>  #
>  # Since: 1.4

The way you wrote it makes it look like the since 2.6 and since 1.4 tags
both apply to the overall struct, which is not true.

>  ##
>  { 'struct': 'ChardevFile', 'data': { '*in' : 'str',
> -                                   'out' : 'str' } }
> +                                   'out' : 'str',
> +                                   '*append': 'bool' } }
>  
>  ##
>  # @ChardevHostdev:
> diff --git a/qemu-char.c b/qemu-char.c
> index 5448b0f..58454e2 100644
> --- a/qemu-char.c
> +++ b/qemu-char.c
> @@ -3479,6 +3479,7 @@ static void qemu_chr_parse_file_out(QemuOpts *opts, ChardevBackend *backend,
>      }
>      backend->u.file = g_new0(ChardevFile, 1);
>      backend->u.file->out = g_strdup(path);
> +    backend->u.file->append = qemu_opt_get_bool(opts, "append", false);

You also need to set backend->u.file->has_append. (Because you are
always initializing it, with a default of false, you can set has_append
to true, rather than worrying about whether the user provided an
"append" option.)

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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