[PATCH v6 2/7] chardev/char: split chardev_init_common() out of qemu_char_open()

Vladimir Sementsov-Ogievskiy posted 7 patches 1 week, 3 days ago
Maintainers: "Marc-André Lureau" <marcandre.lureau@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, "Daniel P. Berrangé" <berrange@redhat.com>, Eduardo Habkost <eduardo@habkost.net>
[PATCH v6 2/7] chardev/char: split chardev_init_common() out of qemu_char_open()
Posted by Vladimir Sementsov-Ogievskiy 1 week, 3 days ago
We are going to share new chardev_init_logfd() with further
alternative initialization interface. Let qemu_char_open() be
a wrapper for .open(), and its artifacts (handle be_opened if
was not set to false by backend, and filename).

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 chardev/char.c | 50 ++++++++++++++++++++++++++++++++------------------
 1 file changed, 32 insertions(+), 18 deletions(-)

diff --git a/chardev/char.c b/chardev/char.c
index 3e432195a5..216c95c053 100644
--- a/chardev/char.c
+++ b/chardev/char.c
@@ -250,22 +250,6 @@ static void qemu_char_open(Chardev *chr, ChardevBackend *backend,
                            bool *be_opened, Error **errp)
 {
     ChardevClass *cc = CHARDEV_GET_CLASS(chr);
-    /* Any ChardevCommon member would work */
-    ChardevCommon *common = backend ? backend->u.null.data : NULL;
-
-    if (common && common->logfile) {
-        int flags = O_WRONLY;
-        if (common->has_logappend &&
-            common->logappend) {
-            flags |= O_APPEND;
-        } else {
-            flags |= O_TRUNC;
-        }
-        chr->logfd = qemu_create(common->logfile, flags, 0666, errp);
-        if (chr->logfd < 0) {
-            return;
-        }
-    }
 
     if (cc->open) {
         cc->open(chr, backend, be_opened, errp);
@@ -1000,6 +984,29 @@ void qemu_chr_set_feature(Chardev *chr,
     return set_bit(feature, chr->features);
 }
 
+static bool chardev_init_common(Chardev *chr, ChardevBackend *backend,
+                                Error **errp)
+{
+    /* Any ChardevCommon member would work */
+    ChardevCommon *common = backend ? backend->u.null.data : NULL;
+
+    if (common && common->logfile) {
+        int flags = O_WRONLY;
+        if (common->has_logappend &&
+            common->logappend) {
+            flags |= O_APPEND;
+        } else {
+            flags |= O_TRUNC;
+        }
+        chr->logfd = qemu_create(common->logfile, flags, 0666, errp);
+        if (chr->logfd < 0) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
 static Chardev *chardev_new(const char *id, const char *typename,
                             ChardevBackend *backend,
                             GMainContext *gcontext,
@@ -1020,11 +1027,14 @@ static Chardev *chardev_new(const char *id, const char *typename,
     chr->label = g_strdup(id);
     chr->gcontext = gcontext;
 
+    if (!chardev_init_common(chr, backend, errp)) {
+        goto fail;
+    }
+
     qemu_char_open(chr, backend, &be_opened, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
-        object_unref(obj);
-        return NULL;
+        goto fail;
     }
 
     if (!chr->filename) {
@@ -1035,6 +1045,10 @@ static Chardev *chardev_new(const char *id, const char *typename,
     }
 
     return chr;
+
+fail:
+    object_unref(obj);
+    return NULL;
 }
 
 Chardev *qemu_chardev_new(const char *id, const char *typename,
-- 
2.48.1


Re: [PATCH v6 2/7] chardev/char: split chardev_init_common() out of qemu_char_open()
Posted by Vladimir Sementsov-Ogievskiy 1 week ago
On 04.11.25 13:17, Vladimir Sementsov-Ogievskiy wrote:
> We are going to share new chardev_init_logfd() with further
> alternative initialization interface. Let qemu_char_open() be
> a wrapper for .open(), and its artifacts (handle be_opened if
> was not set to false by backend, and filename).
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> ---
>   chardev/char.c | 50 ++++++++++++++++++++++++++++++++------------------
>   1 file changed, 32 insertions(+), 18 deletions(-)
> 
> diff --git a/chardev/char.c b/chardev/char.c
> index 3e432195a5..216c95c053 100644
> --- a/chardev/char.c
> +++ b/chardev/char.c
> @@ -250,22 +250,6 @@ static void qemu_char_open(Chardev *chr, ChardevBackend *backend,
>                              bool *be_opened, Error **errp)
>   {
>       ChardevClass *cc = CHARDEV_GET_CLASS(chr);
> -    /* Any ChardevCommon member would work */
> -    ChardevCommon *common = backend ? backend->u.null.data : NULL;
> -
> -    if (common && common->logfile) {
> -        int flags = O_WRONLY;
> -        if (common->has_logappend &&
> -            common->logappend) {
> -            flags |= O_APPEND;
> -        } else {
> -            flags |= O_TRUNC;
> -        }
> -        chr->logfd = qemu_create(common->logfile, flags, 0666, errp);
> -        if (chr->logfd < 0) {
> -            return;
> -        }
> -    }
>   
>       if (cc->open) {
>           cc->open(chr, backend, be_opened, errp);
> @@ -1000,6 +984,29 @@ void qemu_chr_set_feature(Chardev *chr,
>       return set_bit(feature, chr->features);
>   }
>   
> +static bool chardev_init_common(Chardev *chr, ChardevBackend *backend,
> +                                Error **errp)
> +{
> +    /* Any ChardevCommon member would work */
> +    ChardevCommon *common = backend ? backend->u.null.data : NULL;
> +
> +    if (common && common->logfile) {
> +        int flags = O_WRONLY;
> +        if (common->has_logappend &&
> +            common->logappend) {
> +            flags |= O_APPEND;
> +        } else {
> +            flags |= O_TRUNC;
> +        }
> +        chr->logfd = qemu_create(common->logfile, flags, 0666, errp);
> +        if (chr->logfd < 0) {
> +            return false;
> +        }
> +    }
> +
> +    return true;
> +}
> +
>   static Chardev *chardev_new(const char *id, const char *typename,
>                               ChardevBackend *backend,
>                               GMainContext *gcontext,
> @@ -1020,11 +1027,14 @@ static Chardev *chardev_new(const char *id, const char *typename,
>       chr->label = g_strdup(id);
>       chr->gcontext = gcontext;
>   
> +    if (!chardev_init_common(chr, backend, errp)) {
> +        goto fail;
> +    }
> +
>       qemu_char_open(chr, backend, &be_opened, &local_err);
>       if (local_err) {
>           error_propagate(errp, local_err);
> -        object_unref(obj);
> -        return NULL;
> +        goto fail;
>       }
>   
>       if (!chr->filename) {
> @@ -1035,6 +1045,10 @@ static Chardev *chardev_new(const char *id, const char *typename,
>       }
>   
>       return chr;
> +
> +fail:
> +    object_unref(obj);
> +    return NULL;
>   }
>   
>   Chardev *qemu_chardev_new(const char *id, const char *typename,


This commit means that we'll not migrate the logfd.. But why not? I have not current plans
to support migration of serial port devices, but seems good to save a possibility for it
now.

At least, if not support now, I should explicitly error-out on trying to migreate chardev
with logfd, instead of silently recreate the file on target (which will actually break
source, which continue writing to it)

-- 
Best regards,
Vladimir